RU2817117C2 - Method and device for intraframe prediction - Google Patents

Abstract

FIELD: image encoding and decoding.

SUBSTANCE: invention relates to the technology of encoding and decoding an image and, in particular, to a method and device for encoding/decoding of internal prediction. Disclosed is an intraframe prediction device configured to obtain an intraframe prediction mode of the current block, determining, among a plurality of pixel lines, a pixel line for intraframe prediction of the current block and performing intraframe prediction of current block based on intraframe prediction mode and pixel line, wherein obtaining includes: obtaining an internal prediction mode based on a predetermined default mode or a group of most probable modes (MPM) candidates. In addition, the first reference pixel of the determined pixel line can be selectively filtered, and the prediction pixel of the current block can be selectively corrected, and thus the intraframe prediction accuracy can be improved.

EFFECT: high efficiency of compressing images.

20 cl, 35 dwg, 5 tbl

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

[0001] The present invention relates to an image encoding and decoding technology, and in particular to a method and apparatus for intra prediction encoding/decoding.

BACKGROUND OF THE ART

[0002] Recently, the demand for high-resolution and high-quality images, such as high-definition (HD) images and ultra-high-definition (UHD) images, has been increasing in various applications, and therefore, highly efficient image compression techniques are being developed.

[0003] As for the image compression technology, there may be various technologies, such as an inter-picture prediction technology in which the value of a pixel included in the current frame is predicted based on a frame before or after the current frame, an intra prediction technology in which the value of a pixel included in the current frame is predicted using information of the pixel in the current frame, and entropy encoding technology for assigning a short code to information having a high frequency of occurrence and assigning a long code to information having a low frequency of occurrence. These image compression technologies can be used to efficiently compress and transmit or store image data.

SUMMARY OF THE INVENTION

Technical problem

[0004] The present invention relates to an image encoding and decoding technology, and in particular to a method and apparatus for intra prediction encoding/decoding.

Technical solution

[0005] According to the method and apparatus for intra prediction according to the present invention, the intra prediction mode of the current block can be obtained, among a plurality of pixel lines, a pixel line for intra prediction of the current block can be determined, and based on the intra prediction mode and the determined pixel line intra prediction of the current block can be performed.

[0006] According to the method and apparatus for intra prediction according to the present invention, filtering can be performed on the first reference pixel of a certain line of pixels.

[0007] According to the intra prediction method and apparatus of the present invention, filtering may be selectively performed based on a first flag indicating whether the first reference pixel for intra prediction has been filtered.

[0008] According to the method and apparatus for intra prediction according to the present invention, the first flag may be obtained from the apparatus for decoding based on an encoding parameter of the current block, and the encoding parameter may comprise at least one of block size, component type, intra mode prediction or whether intra prediction was applied to the subblock elements.

[0009] According to the method and apparatus for intra prediction according to the present invention, correction can be performed with respect to the prediction pixel of the current block in accordance with the intra prediction.

[0010] According to the method and apparatus for intra prediction according to the present invention, the operation of performing correction may further include: determining at least one of the second reference pixel or weighted value for correction based on the prediction pixel position of the current block.

[0011] According to the method and apparatus for intra prediction according to the present invention, correction may be selectively performed taking into account at least one of the pixel line position of the current block, the intra prediction mode of the current block, or whether intra prediction has been performed on subblock elements of the current block. block.

[0012] According to the method and apparatus for intra prediction according to the present invention, intra prediction may be performed on subblock elements of the current block, and the subblocks may be determined based on at least one of the second flag indicating whether to perform division, information about partition direction or partition number information.

[0013] According to the method and apparatus for intra prediction according to the present invention, the intra prediction mode can be obtained based on a predetermined default mode or a plurality of most probable modes (MPM) candidates.

Technical effect

[0014] According to the present invention, by making prediction in subblock elements, encoding/decoding efficiency can be improved.

[0015] According to the present invention, by intra prediction based on multiple pixel lines, the efficiency of intra prediction encoding/decoding can be improved.

[0016] According to the present invention, by performing filtering on a reference pixel, the efficiency of intra prediction encoding/decoding can be improved.

[0017] According to the present invention, by correcting the intra prediction pixel, the efficiency of intra prediction encoding/decoding can be improved.

[0018] According to the present invention, by obtaining an intra prediction mode based on a default mode or a candidate MPM, the encoding/decoding efficiency of the intra prediction mode can be improved.

BRIEF DESCRIPTION OF GRAPHIC MATERIALS

[0019] In FIG. 1 is a block diagram of an image encoding apparatus according to an embodiment of the present invention.

[0020] In FIG. 2 is a block diagram of an image decoding apparatus according to an embodiment of the present invention.

[0021] In FIG. Figure 3 shows a schematic diagram depicting the tree-like form of the block.

[0022] In FIG. Figure 4 is a schematic diagram depicting a typical block shape.

[0023] In FIG. 5 is a schematic diagram showing various block shapes that can be obtained by using the block separating section according to the present invention.

[0024] In FIG. 6 is a schematic diagram for explaining a tree division according to an embodiment of the present invention.

[0025] In FIG. 7 is a schematic diagram for explaining a tree division according to an embodiment of the present invention.

[0026] In FIG. 8 illustrates a block division method according to an embodiment of the present invention.

[0027] In FIG. 9 is a circuit diagram showing an intra prediction mode predetermined in the image encoding/decoding apparatus.

[0028] In FIG. Figure 10 shows an example of comparing pixels from different color spaces to obtain correlation information.

[0029] In FIG. 11 is a circuit diagram for explaining the configuration of reference pixels for intra prediction.

[0030] In FIG. 12 is a circuit diagram for explaining the range of a reference pixel for intra prediction.

[0031] In FIG. 13 is a diagram showing a block adjacent to a current block for generating a prediction block.

[0032] In FIG. 14 and 15 show some examples of confirming the division information of each block.

[0033] In FIG. 16 is a schematic diagram showing various situations of block division.

[0034] In FIG. 17 illustrates an example of block division according to an embodiment of the present invention.

[0035] In FIG. 18 shows various examples of candidate intra prediction mode groups for tuning blocks generating prediction information (the prediction blocks in this example are 2N×N blocks).

[0036] In FIG. 19 illustrates various examples of candidate intra prediction mode groups for configuring blocks generating prediction information (the prediction blocks in this example are N×2N blocks).

[0037] In FIG. 20 illustrates an example of block division according to an embodiment of the present invention.

[0038] In FIG. 21 and 22 illustrate various examples of candidate intra prediction mode groups for tuning blocks generating prediction information.

[0039] In FIG. 23 to 25 show examples of generating a prediction block in accordance with the contiguous block prediction mode.

[0040] In FIG. 26 is a schematic diagram of the relationship between the current block and the adjacent block.

[0041] In FIG. 27 and 28 show intra prediction considering the directionality of the prediction mode.

[0042] In FIG. 29 is a circuit diagram for explaining the configuration of reference pixels for intra prediction.

[0043] In FIG. 30-35 show schematic diagrams regarding the configuration of reference pixels.

DETAILED DESCRIPTION

[0044] The intra prediction method and apparatus of the present invention is configured to obtain an intra prediction mode of a current block, determine among a plurality of pixel lines a pixel line for intra prediction of the current block, and perform intra prediction of the current block based on the intra prediction mode and the determined pixel line.

[0045] According to the intra prediction method and apparatus of the present invention, the first reference pixel of a certain line of pixels may be filtered.

[0046] According to the intra prediction method and apparatus of the present invention, filtering may be selectively performed based on a first flag indicating whether the first reference pixel for intra prediction has been filtered.

[0047] According to the method and apparatus for intra prediction according to the present invention, the first flag may be obtained from the apparatus for decoding based on an encoding parameter of the current block, and the encoding parameter may comprise at least one of block size, component type, intra mode prediction or whether intra prediction was applied to the subblock elements.

[0048] According to the method and apparatus for intra prediction according to the present invention, correction can be performed with respect to the prediction pixel of the current block in accordance with the intra prediction.

[0049] According to the method and apparatus for intra prediction according to the present invention, the correction operation may further include: determining at least one of the second reference pixel or weighted value for correction based on the prediction pixel position of the current block.

[0050] According to the method and apparatus for intra prediction according to the present invention, the correction operation may be selectively performed taking into account at least one of the pixel line position of the current block, the intra prediction mode of the current block, or whether intra prediction has been performed on subblock elements current block.

[0051] According to the method and apparatus for intra prediction according to the present invention, intra prediction may be performed on subblock elements of the current block, and the subblocks may be determined based on at least one of the second flag indicating whether to perform division, information about partition direction or partition number information.

[0052] According to the method and apparatus for intra prediction according to the present invention, the intra prediction mode can be obtained based on a predetermined default mode or a plurality of candidate MPMs.

[0053] Various modifications may be made to the present invention and various embodiments may be provided, and specific embodiments will be described in detail with reference to the accompanying drawings. However, it should be understood that the present invention is not limited to these specific embodiments, but is intended to include all changes, equivalents and substitutions that fall within the spirit and scope of the present invention.

[0054] Terms such as first, second, A and B may be used to describe various elements, but these elements should not be limited to such terms. These terms are intended only to distinguish one element from another. For example, the first element may be referred to as the second element, and likewise, the second element may be referred to as the first element without departing from the scope of the present invention. The term “and/or” may include a combination of a plurality of related listed entities or any of a plurality of related listed entities.

[0055] It should be understood that when an element is said to be "connected" or "coupled" to another element, the element may be directly connected or connected to the other element. However, it should be understood that there may be another element present in between. On the other hand, if an element is said to be "directly connected" or "directly connected" to another element, it should be understood that there is no other element between them.

[0056] The terms used in this application are used only to describe specific embodiments and are not intended to limit the present invention. Singular forms include plural forms unless the context clearly indicates otherwise. As used herein, a term such as “include” or “have” is intended to indicate the presence of the features, numbers, steps, acts, components, parts, or combinations thereof described in the specification, and it is to be understood that the term does not exclude the possibility of having or adding one or more other features or numbers, steps, actions, components, parts, or combinations thereof.

[0057] Unless otherwise indicated, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one skilled in the art to which the present invention relates. Terms such as those defined in a commonly used vocabulary should be interpreted as corresponding to the meanings of the relevant technology and should not be interpreted as ideal or overly formal meanings unless they are expressly defined herein.

[0058] The video encoding and decoding devices may be user terminals such as a personal computer (PC), laptop, personal digital assistant (PDA), portable media player (PMP), PlayStation Portable (PSP) game console, wireless communication terminal , smartphone, TV, virtual reality (VR) device, augmented reality (AR) device, mixed reality (MR) device, head-mounted display (HMD) and smart glasses, or server terminals such as an application server and a service server, and may include includes various devices such as a communication device containing a communication modem for communicating with various devices or wired/wireless communication networks, a storage device for storing various programs and data for encoding or decoding an image or for performing prediction carried out between images or within images, for encoding or decoding, a processor for executing a program to perform calculation and control operations, etc. In addition, an image encoded as a bitstream by the image encoding apparatus may be transmitted to the image decoding apparatus in real time or non-real time via a wired or wireless network such as the Internet, a local area network, a wireless LAN, a network WiBro or mobile phone network, or through various communication interfaces such as cable and universal serial bus (USB), is decoded by the image decoding device and reconstructed and reproduced as an image.

[0059] In addition, an image encoded as a bitstream by the image encoding apparatus may be transmitted from the encoding apparatus to the decoding apparatus via a computer-readable storage medium.

[0060] The above-described image encoding device and image decoding device, respectively, may be separate devices. However, the devices may be configured as a single image encoding/decoding device according to the implementation. In this case, some components of the image encoding device are essentially the same technical elements as some components of the image decoding device, and can be implemented with at least the same structure or perform at least the same function as some components devices for decoding images.

[0061] Therefore, redundant descriptions of the respective technical elements will be omitted in the detailed description of the following technical elements and their operating principles.

[0062] In addition, since the image decoding device corresponds to a computing device that applies an image encoding method performed by the image encoding device to decoding, the following description will focus on the image encoding device.

[0063] The computing device may include a storage device on which a program or software module implementing an image encoding method and/or an image decoding method is stored, and a processor coupled to the storage device for executing the program. In addition, a device for encoding an image may be called an encoder, and a device for decoding an image may be called a decoder.

[0064] Typically, an image may be configured as a series of still images, wherein these still images may be classified into Group of Pictures (GOP) elements, and each still image may be referred to as a frame. In this case, a frame may represent one of a frame or a field in a progressive scan signal or an interlaced signal, and the image may be expressed as a "frame" if encoding/decoding is performed in frame elements, and expressed as a "field" if encoding /decoding is performed in field elements. The present invention contemplates and describes a progressive scan signal. However, the present invention can also be applied to an interlaced signal. In a higher level concept, elements such as GOP and sequence may exist, and each frame may be divided into predefined areas such as slices, tiles, and blocks. In addition, one GOP may contain elements such as an I frame, a P frame, and a B frame. An I frame may refer to a frame that is itself encoded/decoded without using a reference frame, and a P frame and a B frame may refer to frames that are encoded /decoded by performing a process such as motion estimation and motion compensation using a reference frame. In general, an I frame and a P frame can be used as reference frames in the case of a P frame, and an I frame and a P frame can be used as reference frames in the case of a B frame. However, the above definition can be changed by encoding/decoding settings.

[0065] Here, the frame to be encoded/decoded is called a reference frame, and the block or pixel associated with it is called a reference block or reference pixel. In addition, the reference data may be not only a pixel value in the spatial domain, but also a coefficient value in the frequency domain and various types of encoding/decoding information generated and determined during the encoding/decoding process. Examples thereof may be intra prediction related information or motion related information in the prediction section, transformation related information in the transform section/inverse transform section, quantization related information in the quantization section/inverse quantization section, information encoding/decoding related information (contextual information) in the encoding section/decoding section, filter related information in the filter section in the loop, etc.

[0066] The smallest element that makes up an image may be a pixel, and the number of bits used to represent one pixel is called the bit depth. In general, the bit depth can be 8 bits, and according to the encoding settings, bit depths greater than 8 bits can be supported. As a bit depth, at least one bit depth according to a color space may be supported. In addition, the at least one color space may be configured to match the color format of the image. One or more frames having a certain size, or one or more frames having different sizes, may be provided according to the color format. For example, in the case of YCbCr 4:2:0, one luma component (Y in this example) and two color difference components (Cb/Cr in this example) may be provided. In this example, the component ratio of the chrominance components and the luminance component may be a 1:2 ratio in width and height. As another example, in the case of 4:4:4, the width and height may be the same in component ratio. If there are one or more color spaces, as in the example above, the frame can be divided into the corresponding color spaces.

[0067] In the present invention, description will be given based on some color spaces (Y in this example), some color formats (YCbCr in this example), and the same or similar application (tuning depending on the specific color space) can be applied to others color spaces (Cb and Cr in this example) according to the color format. However, each color space may have some differences (independent of the setting for a particular color space). In other words, a setting that is specific to each color space may mean that there is a setting that is related to or dependent on the component ratio of each component (e.g., 4:2:0, 4:2:2, 4:4:4, etc.). etc.), and an independent setting for each color space may mean that there is only a setting for the corresponding color space, not taking into account or depending on the component ratio of each component. In the present invention, depending on the encoder/decoder, some configurations may have independent or dependent settings.

[0068] Setting information or a syntax element required in the image encoding process may be defined at the element level, such as video, sequence, frame, slice, tile, block, etc., which is included in the bitstream in the elements, such as Video Parameter Set (VPS), Sequence Parameter Set (SPS), Frame Parameter Set (PPS), Slice Header, Tile Header, Block Header, etc., and is passed to the encoder, and the decoder can perform analysis in the elements of that same layer to recover the setting information transmitted from the encoder, and use the recovered setting information in the image decoding process. In addition, the associated information can be transmitted as a bit stream in the form of additional optimization information (SEI) or metadata, and it can be analyzed and used. Each set of options has a unique ID value, and the bottom set of options can have the ID value of the top set of options that should be referenced. For example, the lower parameter set may refer to information from the upper parameter set having the same ID value among one or more upper parameter sets. Among the examples of various elements mentioned above, when one element includes one or more other elements, the corresponding element may be called a top element, and the included element may be called a bottom element.

[0069] The setting information generated in an element may include content regarding an independent setting for each element, or include content regarding a setting dependent on a previous, subsequent, or top element. In this case, the dependent setting can be understood as indicating information about the settings of the corresponding element as flag information indicating that the setting of the previous, subsequent or top element is respected (for example, a 1-bit flag, the setting is respected in case 1 and not respected in case 0) . The description of the setting information in the present invention will focus on an example of independent setting. However, an example of adding or replacing content depending on the setting information of the previous or subsequent element relative to the current element or the top element may be included.

[0070] In FIG. 1 is a block diagram of an image encoding apparatus according to an embodiment of the present invention. In fig. 2 is a block diagram of an image decoding apparatus according to an embodiment of the present invention.

[0071] With reference to FIG. 1, an image encoding apparatus may include a prediction section, a subtraction section, a transform section, a quantization section, an inverse quantization section, an inverse transform section, an addition section, an in-loop filter section, a storage device, and/or an encoding section. Some of the above components may optionally be included, some or all of the components may be selectively included as needed, and some other configurations not depicted in the figure may be included.

[0072] With reference to FIG. 2, an image decoding apparatus may include a decoding section, a prediction section, an inverse quantization section, an inverse transform section, an adding section, an in-loop filter section, and/or a storage device. Some of the above components may optionally be included, some or all of the components may be selectively included as needed, and some other configurations not depicted in the figure may be included.

[0073] The image encoding device and the image decoding device may be separate devices, but may be configured as an image encoding/decoding device according to implementation. In this case, some configurations of the image encoding apparatus are substantially the same technical elements as some components of the image decoding apparatus, and may be implemented with at least the same structure or perform at least the same function as some components devices for decoding images. Therefore, redundant descriptions of the corresponding technical elements will be omitted in the detailed description of the following technical elements and their operating principles. Since the image decoding apparatus corresponds to a computing device that applies an image encoding method performed by the image encoding apparatus to decoding, the following description will focus on the image encoding apparatus. A device for encoding an image may be called an encoder, and a device for decoding a video may be called a decoder.

[0074] The prediction section may include an intra prediction section that performs intra prediction and an inter-picture prediction section that performs inter-picture prediction. In intra prediction, an intra prediction mode can be determined by configuring a pixel of a block adjacent to a current block as a reference pixel, and a prediction block can be generated using the intra prediction mode. In inter-picture prediction, a prediction block may be generated by determining motion information of a current block using one or more reference images and performing motion compensation using the motion information. For use with respect to the current block, one of intra prediction and inter-picture prediction (coding element or prediction element) may be determined, and specific information (for example, intra prediction mode, motion vector, reference video, etc.) may be determined. ) according to each prediction method. In this case, the processing element in which the prediction is performed and the processing element in which the prediction method and the specific content are determined can be determined according to the encoding/decoding setting. For example, prediction method, prediction mode, etc. are defined in a prediction element (or encoding element), and the prediction is performed in a prediction block element (or encoding element or transform element).

[0075] The subtraction section generates a residual block by subtracting the prediction block from the current block. That is, the subtraction section calculates the difference between the pixel value of each pixel in the current block to be encoded and the predicted pixel value of each pixel in the prediction block that is generated by the prediction section to generate a residual block that represents a residual signal in the image.

[0076] The conversion section can convert a signal belonging to the spatial domain into a signal belonging to the frequency domain, and the signal resulting from the conversion process is called a converted coefficient. For example, a transform block containing a transformed coefficient can be obtained by transforming a residual block having a residual signal received from the subtraction section, and the input signal is determined according to the encoding setting and is not limited by the residual signal.

[0077] The transform section may transform the residual block using a transform scheme such as the Hadamard transform, discrete sine transform (DST-based transform), or discrete cosine transform (DCT-based transform). However, the conversion circuit is not limited to this, and various conversion circuits obtained by improving and modifying this conversion circuit can be used.

[0078] For example, at least one conversion scheme may be supported in a conversion, and at least one detailed conversion scheme may be supported in each conversion scheme. In this case, the at least one detailed transformation circuit may be a transformation circuit in which a portion of the basis vector is configured differently in each transformation method. For example, how conversion technologies can support DST-based and DCT-based conversions. For DST, detailed conversion schemes such as DST-I, DST-II, DST-III, DST-V, DST-VI, DST-VII and DST-VIII can be supported. For DCT, detailed conversion schemes such as DCT-I, DCT-II, DCT-III, DCT-V, DCT-VI, DCT-VII and DCT-VIII can be supported.

[0079] One of the transformations (eg, transformation scheme and detailed transformation scheme) can be set as a basic transformation scheme. Therefore, additional conversion schemes (eg, multiple conversion schemes and multiple detailed conversion schemes) may be supported. You can define support for additional transformation scheme in sequence, frame, slice, tile, etc. elements. such that associated information can be generated in a given element and, if additional mapping scheme is supported, mapping circuit selection information can be defined to generate associated information in elements such as blocks.

[0080] The conversion can be performed in the horizontal/vertical direction. For example, using a basis vector in the transform, a complete two-dimensional transform can be performed by performing a one-dimensional transform in the horizontal direction and performing a one-dimensional transform in the vertical direction, thereby converting a pixel value in the spatial domain to a pixel value in the frequency domain.

[0081] In addition, the horizontal/vertical direction conversion can be performed adaptively. In more detail, execution of the adaptive transform may be determined in accordance with at least one encoding setting. For example, in the case of internal conversion, if the conversion mode is a horizontal mode, DCT-I may be applied in the horizontal direction, and DST-I may be applied in the vertical direction. If the conversion mode is a vertical mode, DST-VI can be applied in the horizontal direction, and DCT-VI can be applied in the vertical direction. In the case of diagonal down left mode, DCT-II can be used in the horizontal direction, and DCT-V can be used in the vertical direction. In case of diagonal down right mode, in the horizontal direction DST-I can be applied, and in the vertical direction DST-VI can be applied.

[0082] The size and shape of each transform block may be determined according to the cost of each candidate encoding the size and shape of the transform block, and information such as certain image data of each transform block and the determined size and shape of each transform block may be encoded.

[0083] The square transform in the transform shape may be specified as the base transform shape, and additional transform shapes (eg, rectangular shapes) may be supported. Support for additional transformation forms can be defined in sequence, frame, slice, tile, etc. elements, associated information can be generated within a given element, and transformation form selection information can be defined to generate associated information in elements such as blocks .

[0084] In addition, according to the encoding information, support for the transform block format can be determined. In this case, the encoding information may correspond to the slice type, encoding mode, block size and shape, block division mode, etc. That is, one transform form may be supported in accordance with at least one kind of encoding information, and a plurality of transform forms may be supported in accordance with at least one kind of encoding information. The first case may be an implicit case, and the last case may be an explicit case. Optionally, adaptive selection information indicating the best candidate group among the plurality of candidate groups may be generated and included in the bit stream. It is understood that in the present invention, including the present example, when generating encoding information explicitly, the corresponding information is included in the bitstream in various elements, and to recover the decoded information, the decoder analyzes the related information in various elements. In addition, it is understood that when processing the encoding/decoding information implicitly, the encoder and the decoder perform processing using the same method and rule.

[0085] As an example, support for transforming rectangular shapes may be determined according to the slice type. In the case of an I slice, the supported transform may be a square transform, and in the case of a P/B slice, the transform may be a square or rectangular transform.

[0086] As an example, support for converting rectangular shapes may be determined according to the encoding mode. In the case of intra prediction, the supported transform form may be a square transform, and in the case of inter-image prediction, the supported transform may be a square or rectangular transform.

[0087] As an example, support for transforming rectangular shapes can be determined according to the block size and type. The transform shape supported in a predefined or larger block size may be a square shape transform, and the transform shape supported in a predefined or smaller size block may be a square or rectangular shape transform.

[0088] As an example, support for converting rectangular shapes may be determined according to a block division mode. If the block to be transformed is a block obtained by a quaternary tree partitioning mode, the supported transform shape may be a square transformation, and if the block is a block obtained by a binary tree partitioning mode, the supported shape The transformation can be a square or rectangular transformation.

[0089] The above example is an example of supporting a transform shape according to one piece of encoding information, and multiple pieces of information can be combined to participate in setting supported additional transform shapes. The above example is not limited to the above examples, but is directed to examples in which additional transform forms are supported according to different encoding settings, and various modification examples can be implemented.

[0090] According to encoding settings or image characteristics, the conversion process may be omitted. For example, the conversion process (including the inverse process) can be omitted according to encoding settings (this example assumes lossless compression conditions). In another example, the conversion process may be omitted if performing compression by conversion is not applied according to the characteristics of the image. In this case, the omitted transformation may be the entire element, or one of the horizontal and vertical elements may be omitted, and it can be determined whether such omission is supported according to the size and shape of the block.

[0091] For example, in a setting where the omit horizontal and vertical transforms are coupled, if the omit transform flag is 1, no transform is performed in the horizontal and vertical directions, and if the flag is 0, the transform is performed in the horizontal and vertical directions. In a setting where the horizontal and vertical transformation operations are performed independently, if the first transform omit flag is 1, no transformation is performed in the horizontal direction, and if the flag is 0, the transformation is performed in the horizontal direction. If the second conversion omit flag is 1, no conversion is performed in the vertical direction, and if the flag is 0, conversion is performed in the vertical direction.

[0092] In case the block size is in range A, conversion omission may be supported, and in case of range B, conversion omission may not be supported. For example, if the horizontal block length is greater than M, or the vertical block length is greater than N, the conversion omit flag cannot be supported, and if the horizontal block length is less than m, or the vertical block length is less than n, the conversion omit flag may be supported. M(m) and N(n) can be the same or different. Transform-related settings can be defined in sequence, frame, slice, etc. elements.

[0093] If additional conversion schemes are supported, the conversion scheme settings may be determined in accordance with the at least one piece of encoding information. In this case, the encoding information may correspond to the slice type, encoding mode, block size and shape, prediction mode, etc.

[0094] As an example, support for a conversion scheme may be determined according to an encoding mode. For intra prediction, the supported transformation schemes may be DCT-I, DCT-III, DCT-VI, DST-II and DST-III, and for inter-image prediction, the supported transformation schemes may be DCT-II, DCT-III and DST -III.

[0095] As an example, support for a transformation scheme may be determined according to the slice type. In the case of slice I, the supported conversion schemes may be DCT-I, DCT-II and DCT-III, in the case of slice P, the supported conversion schemes may be DCT-V, DST-V and DST-VI, and in the case of slice B, the supported conversion schemes may be DCT-I, DCT-II and DST-III.

[0096] As an example, support for a conversion scheme may be determined in accordance with a prediction mode. The conversion circuits supported in prediction mode A may be DCT-1 and DCT-II, the conversion circuits supported in prediction mode B may be DCT-1 and DST-1, and the conversion circuit supported in prediction mode C may be DCT-I. In this case, prediction modes A and B may be directional modes, and prediction mode C may be a non-directional mode.

[0097] As an example, support for a conversion scheme may be determined according to the block size and type. The conversion scheme supported for blocks with sizes that are larger than a certain size may be DCT-II, the conversion schemes supported for blocks with sizes that are less than a certain size can be DCT-II and DST-V, and the conversion schemes supported for blocks with sizes greater and less than a certain size may be DCT-I, DCT-II and DST-I. In addition, the conversion circuits supported in square form may be DCT-1 and DCT-II, and the conversion circuits supported in rectangular form may be DCT-1 and DST-1.

[0098] The above examples are examples of supporting a conversion scheme according to one piece of encoding information, and multiple pieces of information can be combined to participate in the configuration of supported additional conversion technologies. The examples are not limited to the above examples, but can also be converted into other examples. In addition, the transform section may transmit information needed to generate a transform block to the encoding section for encoding the information, incorporating the information into a bitstream and transmitting to the decoder, and the decoding section of the decoder analyzes the information and uses the information for the deconversion process.

[0099] The quantization section is configured to quantize the input signal, and the signal resulting from the quantization process is called a quantized coefficient. For example, a quantization block with a quantized coefficient can be obtained by quantizing a residual block containing a residual transform coefficient received from the transform section. In this case, the input signal is determined according to the encoding setting, which is not limited by the residual conversion gain.

[00100] The quantization section is configured to quantize the transformed residual block using a quantization technology such as uniform threshold quantization with dead zone and weighted quantization matrix. However, the quantization technology is not limited to this, and various quantization technologies obtained by improving and modifying this quantization technology can be used.

[00101] In addition, the quantization section is configured to transmit information necessary to generate a quantization block to the encoding section, whereby the information is encoded, including the information in a bit stream and transmitted to the decoder, and the decoding section of the decoder is configured to analyze the information and use information for the inverse quantization process.

[00102] In the above example, the description has been made under the assumption that the residual block is subjected to transformation and quantization by the transformation section and the quantization section. However, the residual signal of the residual block may be transformed to generate a residual block having a transformed coefficient, and the quantization process may not be performed. Alternatively, the residual signal of the residual block may not be converted to a transformed coefficient, and only a quantization process may be performed. Alternatively, neither the transform process nor the quantization process may be performed. This can be determined based on the encoder settings.

[00103] The encoding section scans the quantized coefficient, the transformed coefficient, or the residual signal of the generated residual block in accordance with at least one scanning order (for example, zigzag scanning, vertical scanning, horizontal scanning, etc.), generating a sequence of quantized coefficients, a sequence the transformed coefficients or signal sequence and may perform encoding using at least one entropy encoding technology. In this case, scanning order information can be determined according to an encoding setting (eg, encoding mode, prediction mode, etc.), and related information can be generated implicitly or explicitly. For example, one of a plurality of scan orders may be selected in accordance with the intra prediction mode. In this case, the scanning pattern can be set to one of various patterns such as zigzag pattern, diagonal lines and raster.

[00104] In addition, encoding data including encoding information transmitted from each component can be generated and output as a bit stream, which can be implemented by a multiplexer (MUX). In this case, encoding may be performed using a method such as exponential Golomb method, context-adaptive variable-length coding (CAVLC), or context-adaptive binary arithmetic coding (CABAC) as the encoding scheme. However, the encoding scheme is not limited to this, and various encoding schemes obtained by improving and modifying this encoding scheme can be used.

[00105] When performing entropy encoding (CABAC assumed in this example) on the residual block data and a syntax element, such as information generated during the encoding/decoding process, the entropy encoding apparatus may comprise a binarizer, a context modeler, and a binary arithmetic coder. In this case, the binary arithmetic encoder may comprise a normal encoding engine and a bypass encoding engine. In this case, the normal encoding engine may be a section executing in relation to the context modeler, and the bypass encoding engine may be a section executing independently of the context modeler.

[00106] Since the syntax element input to the entropy encoding device may not be a binary value, when the syntax elements are not binary values, the binarizer may binarize the syntax elements and output a binary number string containing 0 or 1 .In this case, the binary number is a bit containing 0 or 1 and it can be encoded using a binary arithmetic encoder. In this case, one of the normal encoding engine and the bypass encoding engine can be selected based on the probability of occurrence of 0s and 1s, which can be determined according to the encoding/decoding setting. The bypass encoding engine can be used when the syntax element represents data in which the frequency of occurrence of 0 and 1 is the same, and the normal encoding engine can be used in other cases, which can be referred to when the subsequent normal encoding engine is performed through context modeling ( or updating contextual information).

[00107] In this case, the context is information about the probability of occurrence of a binary number, and context modeling is the process of estimating the probability of a binary number required for binary arithmetic encoding using a binary number that is obtained by conversion to binary form as an input value . A binary number syntax element, an index which is the position of the binary number in a string of binary numbers, the probability that the binary number is included in an adjacent block, etc., may be used to estimate the probability, and may use at least one context table. For example, a plurality of context tables may be used as information for some flags according to the combination of whether neighboring blocks' flags are used.

[00108] When performing conversion of a syntax element to binary form, various methods may be used. For example, the methods can be divided into fixed-length binary conversion and variable-length binary conversion. In the case of variable length binary conversion, you can use unary to binary (truncated unary to binary), truncated Rice binary, order k exponential Golomb binary, truncated binary to binary, and etc. In addition, signed to binary conversion or unsigned to binary conversion may be performed according to the value range of the syntax element. The binarization process for a syntax element carried out in the present invention can be performed including not only the binarization mentioned in the above-described example, but also other additional binarization methods.

[00109] The inverse quantization section and the inverse transform section can be implemented by performing the processes of the transform section and the quantization section in reverse order. For example, the inverse quantization section is configured to inversely quantize the quantized transformed coefficient generated by the quantization section, and the inverse transform section is capable of inversely transforming the inverse quantized transformed coefficient to generate a reconstructed residual block.

[00110] The addition section reconstructs the current block by adding the prediction block and the reconstructed residual block. The reconstructed block can be stored in a memory and used as reference data (prediction section, filter element, etc.).

[00111] The loop filter section may include at least one post-processing filtering component, such as a deblocking filter, a sample adaptive offset (SAO), and an adaptive loop filter (ALF). The deblocking filter can remove block distortion occurring at the boundary between blocks in the reconstructed image. ALF can perform filtering based on the value obtained by comparing the reconstructed image and the input image. In detail, filtering can be performed based on the value obtained by comparing the image reconstructed after filtering a block using a deblocking filter and the input image. Alternatively, filtering can be performed based on the value obtained by comparing the image reconstructed after filtering the block using SAO and the input video.

[00112] The reconstructed block or frame may be stored in a storage device. The reconstructed block or frame stored in the storage device may be provided to a prediction section that performs intra or inter-picture prediction. In detail, a storage space in the form of a queue of a bit stream compressed by an encoder can be treated as a coded frame buffer (CPB), and a space for storing a decoded image in frame elements can be treated as a decoded frame buffer (DPB). In the case of CPB, the decoding elements are stored according to the decoding order, the decoding operation is emulated in the encoder, the bitstream compressed during the emulation process can be stored, the bitstream output from the CPB is reconstructed through the decoding process, the reconstructed image is stored in the DPB, and frames stored in the DPB may be referenced in a subsequent image encoding and decoding process.

[00113] The decoding section may be implemented by performing the process in the encoding section in reverse order. For example, a sequence of quantized coefficients, a sequence of transformed coefficients, or a sequence of signals can be received from a bitstream and decoded, and decoding data including decoding information can be analyzed and transmitted to each component.

[00114] On the other hand, a block dividing section may also be included in the image encoding apparatus and the image decoding apparatus shown in FIGS. 1 and 2, although it is not shown therein. The basic coding element information may be obtained from the frame division section, and the basic coding element may represent a basic (or starting) element used for prediction, transform, quantization, etc. during the image encoding/decoding process. In this case, the encoding elements may be composed into one luminance encoding block and two chroma component encoding blocks according to a color format (YCbCr in this example), and the size of each block may be determined according to the color format. The following examples will implement a block-based description (in this example, the luminance component). In this case, it is assumed that the block is an element that can be obtained after defining each element, and the description will be given with the assumption that similar settings can be applied to other types of blocks.

[00115] A block dividing section can be specified in connection with each component of the image encoding apparatus and the image decoding apparatus, and by this process the size and shape of the block can be determined. In this case, the specified block may be defined differently depending on the configuration and may correspond to a prediction block in the case of a prediction section, a transform block in the case of a prediction section, and a quantization block in the case of a quantization section. The present invention is not limited to this, and block elements may be further defined according to other components. The size and shape of the block can be determined by the horizontal and vertical lengths of the block.

[00116] In the block dividing section, a block can be expressed as M×N, and the maximum and minimum values of each block can be obtained within a range. For example, if the block shape supports a square, and the maximum block value is 256x256, and the minimum block value is 8x8, it is possible to obtain a block having a size of 2 ^m × 2 ^m (in this example, m is an integer from 3 to 8, for example, 8x8, 16x16, 32x32, 64x64, 128x128 or 256x256), a block having a size of 2mx2m (in this example, m is an integer from 4 to 128), or a block , having size m×m (in this example, m is an integer from 8 to 256). Alternatively, in case the block shape supports square and rectangle, and it has the same range as in the example above, it is possible to get a block having size 2 ^m × 2 ⁿ (in this example, m and n are integers from 3 to 8 eg 8×8, 8×16, 16×8, 16×16, 16×32, 32×16, 32×32, 32×64, 64×32, 64×64, 64×128, 128×64 , 128x128, 128x256, 256x128, or 256x256, assuming a maximum width-to-height ratio of 2:1 and, depending on the encoding/decoding setting, there may be no limit to the width-to-height ratio, or there may be a maximum value of this ratio). Alternatively, it is possible to obtain a block having a size of 2m×2n (in this example, m and n are integers from 4 to 128). Alternatively, it is possible to obtain a block having size m×n (in this example, m and n are integers from 8 to 256).

[00117] The resulting blocks may be determined according to the encoding/decoding settings (eg, block type, partitioning scheme, partitioning setting, etc.). For example, as an encoding block a block having size 2 ^m × 2 ⁿ can be obtained, as a prediction block a block having size 2 m × 2n or m × n can be obtained, and as a transform block a block having size 2 ^m × can be obtained. ²ⁿ . Information about block size, range, etc. (eg information related to index and multiplier, etc.) can be generated based on the settings.

[00118] The range (defined in this example as a maximum value and a minimum value) may be determined according to the block type. In addition, for some blocks, block range information may be generated explicitly, and for some blocks, block range information may be implicitly determined. For example, related information may be generated explicitly in an encoding and transform block, and related information may be implicitly processed in a prediction block.

[00119] Explicitly, at least one piece of range information may be generated. For example, in the case of a coding block, the range information may generate maximum value and minimum value information. Alternatively, the information may be generated based on the difference between the maximum value and a predetermined minimum value (eg, 8) (eg, generated based on the setting, value information of the difference between the maximum value and minimum value indices, etc.). In addition, multiple range information can be generated for the horizontal and vertical lengths of a rectangular block.

[00120] Implicitly, range information may be determined based on encoding/decoding settings (eg, block type, partitioning scheme, partitioning setting, etc.). For example, in the case of a prediction block, information about the maximum value and minimum value can be obtained using a group of candidates (in this example, M×N and m/2×n/2), which can be obtained by setting the division of the prediction block (for example, division quaternary tree-based + partition depth 0) in the encoding block (for example, the maximum encoding block size is M×N, and the minimum encoding block size is m×n), which is the top element.

[00121] The size and shape of the initial (or starting) block of the block division section may be determined by the top element. In the case of a coding block, the source block may be a basic coding block obtained from the frame division section, in the case of a prediction block, the source block may be a coding block, and in the case of a transform block, the source block may be a coding block or a prediction block, which may be determined according to with encoding/decoding settings. For example, if the encoding mode is intra prediction, the top element of the transform block may be a prediction block, and if the encoding mode is inter-picture prediction, the prediction block may be an element independent of the transform block. The original block can be divided into smaller blocks as initial division elements. If the optimal size and shape are determined according to the division of each block, the block can be determined as the original block of the lower element. For example, in the first case the block may be an encoding block, and in the latter case (bottom element) it may be a prediction block or a transform block. If the source block of the bottom element is determined as in the above example, a splitting process can be performed to find a block having the optimal size and shape as the top element.

[00122] To summarize, the block dividing section is configured to divide a base encoding element (or a top encoding element) into at least one encoding element (or a lower encoding element). In addition, the encoding element may be divided into at least one prediction element and may be divided into at least one transform element. The encoding element may be divided into at least one encoding block, the encoding block may be divided into at least one prediction block, and may be divided into at least one transform block. The prediction element may be divided into at least one prediction block, and the transformation element may be divided into at least one transformation block.

[00123] As in the above example, if a block having an optimal size and shape is found through the mode determination process, mode information (eg, division information, etc.) can be generated for that block. Mode information may be included in the bitstream along with information generated by the component to which the block belongs (eg, prediction-related information, conversion-related information, etc.) and transmitted to the decoder and may be subjected to analyzed in the same layer element in the decoder and used in the process of decoding the image.

[00124] In the example described below, a division scheme will be described, and the description will be given under the assumption that the original block has a square shape. However, in the case of a rectangular shape, the same or similar example is allowed.

[00125] The block division section is configured to support various division modes. For example, tree partitioning or type partitioning may be supported, and other methods may be used. In the case of a tree partition, a partition flag may be used to generate partition information, and in the case of a typed partition, index information for the shapes of blocks included in a predefined candidate group can be used to generate partition information.

[00126] In FIG. Figure 3 shows a schematic diagram depicting the tree-like form of the block.

[00127] With reference to FIG. 3, “a” depicts one 2N×2N block not subjected to splitting, “b” depicts 2N×N blocks obtained through some split flag (in this example, a horizontal binary tree split), “c” depicts two N×2N blocks , obtained by some split flag (in this example, a vertical binary tree split), and "d" represents four N×N blocks obtained by some split flag (in this example, four quaternary tree splits, or horizontal and vertical binary tree splits ). The shape of the resulting block can be determined according to the type of tree used for division. For example, if a quaternary tree-based partition is performed, the resulting candidate blocks may be blocks "a" and "d". If a binary tree partition is performed, the resulting candidate blocks may be blocks "a", "b" and "c". In the case of a quaternary tree, one split flag is supported. Block "a" can be obtained if the partition flag is "0", and block "b" can be obtained if the partition flag is "1". In the case of a binary tree, a plurality of splitting flags are supported, one of which may be a flag indicating whether splitting is done, one of which may be a flag indicating whether horizontal/vertical splitting is being performed, and one of which may be a flag indicating whether horizontal overlapping is allowed. /vertical separation. If overlap is allowed, the resulting candidate blocks may be blocks "a", "b", "c" and "d", and if overlap is not allowed, the resulting candidate blocks may be blocks "a", "b", and "c" . A quaternary tree may represent a basic tree-like partitioning scheme. Additionally, the tree-based partitioning scheme may include a partitioning scheme based on some tree (in this example, a binary tree). If a flag allowing additional tree-based partitioning is enabled, either implicitly or explicitly, multiple tree-based partitions can be performed. Tree partitioning may be a method that allows for recursive partitioning. That is, the divided block can be again specified as a source block to perform tree division, which can be determined according to division settings such as division range and allowable division depth. This diagram may be an example of a hierarchical partitioning scheme.

[00128] In FIG. Figure 4 is a schematic diagram depicting a typical block shape.

[00129] As shown in FIG. 4, according to the type, the divided block can have 1 division form (in this example - "a"), 2 division forms (in this example - "b", "c", "d", "e", "f" " and "g") and 4 forms of separation (in this example - "h"). The candidate group can be configured using various configurations. For example, in FIG.-5, the candidate group may be configured with a, b, c, n or a, b-g, n, or a, n, q, etc. But this example is not limited to these and includes the following examples, As a result, various transformed examples can be executed. When the flag enabling symmetric partitioning is activated, the supported blocks may be "a", "b", "c" and "h" in FIG. 4, and if the flag enabling asymmetric division is activated, the supported blocks may be all blocks "a"-"h" in FIG. 4. In the first case, the associated information (in this example, the flag that allows symmetric partitioning) can be activated implicitly, and in the latter case, the associated information (in this example, the flag that allows asymmetric partitioning) can be generated explicitly. Typed partitioning may be a way to support one-time partitioning. Compared to tree partitioning, blocks obtained by typed partitioning may not be allowed to further partition. This may represent an example in which the allowable partition depth is zero (eg, single-level partitioning).

[00130] In FIG. 5 is a schematic diagram showing various block shapes that can be obtained by using the block separating section according to the present invention.

[00131] With reference to FIG. 5, blocks a-s may be obtained according to the division setting and division mode, and may also have additional block shapes that are not shown.

[00132] As an example, for tree partitioning, asymmetric partitioning may be allowed. For example, in the case of a binary tree, asymmetric partitioning may be allowed for blocks b and c in FIG. 5 (in this example, the case of multi-block division), or asymmetric division may be allowed for blocks b-g in FIG. 5 (in this example, the case of division into many blocks). If the flag allowing asymmetric partitioning is explicitly or implicitly deactivated according to the encoding/decoding settings, the resulting candidate block may be block b or c (this example assumes that overlapping horizontal and vertical partitions are not allowed), and if the flag allowing asymmetric partitioning is enabled, the resulting candidate blocks can be b, d, e (horizontal partition in this example) or c, f, g (vertical partition in this example). This example may correspond to a case in which the division direction is determined by a horizontal or vertical division flag, and the block shape is determined in accordance with the asymmetry enabling flag. However, the present invention is not limited to these examples, and they can be converted into other examples.

[00133] As an example, an additional tree-based partition may be used for tree partitioning. For example, a division based on a ternary tree, a quaternary tree, an octal tree, etc. can be performed. to obtain n split blocks (in this example - 3, 4 and 8, n is an integer). In the case of a ternary tree, the supported blocks (in this example, divided into multiple blocks) can be h-m blocks. In the case of a quaternary tree, the supported blocks can be n-p blocks. In the case of an octal tree, the supported block may be the q block. Tree support may be implicitly determined according to the encoding/decoding setting, or associated information may be explicitly generated. In addition, depending on the encoding/decoding settings, partitioning can be used alone or in combination with binary tree or quaternary tree partitioning. For example, in the case of a binary tree, blocks such as b and c blocks can be obtained. If the binary tree and the ternary tree are used in combination (in this example, it is assumed that the application range of the binary tree and the application range of the ternary tree partially overlap), blocks such as blocks b, c, i, and l can be obtained. If the flag allowing additional partitioning other than the existing tree is disabled explicitly or implicitly according to the encoding/decoding setting, the resulting candidate block may be block b or c. If this flag is activated, the resulting candidate block may be blocks b and i or blocks b, h, i and j (horizontal split in this example) or may be blocks c and l or blocks c, k, l and m (in this example example - vertical division). This example may correspond to a case in which the dividing direction is determined by a horizontal or vertical dividing flag, and the block shape is determined in accordance with a flag allowing additional division. However, the present invention is not limited to these examples, and these examples are converted into other examples.

[00134] For example, non-rectangular divisions may be allowed for typed blocks. For example, a division in the form of blocks r and s is possible. When combined with the typed group of candidate blocks described above, the supported blocks are blocks a, b, c, h, r, s or a-h, r, s. Additionally, blocks that support n partitions (eg, in this example, n is the integer 3 other than 1, 2, and 4), such as h-m blocks, may be included in the candidate group.

[00135] The division mode can be determined according to the encoding/decoding settings.

[00136] As an example, the division mode may be determined according to the block type. For example, the encoding block and transform block may use a tree division, and the prediction block may use a typed division. Additionally, a combination of the two types of separation can be used. For example, a prediction block may use a division mode in which a tree division is combined with a typed division, and this division mode differs according to at least one range applied to the block.

[00137] For example, the division mode may be determined according to the block size. For example, a tree partition may be performed on some range (eg, a×b-c×d, if the latter is larger) between the maximum value and the minimum value of the block, and a typed partition may be performed on some range (eg, e×f-g×h). In this case, range information according to the division mode may be generated explicitly or may be determined implicitly.

[00138] As an example, the division mode can be determined according to the shape of the block (or the block before division). For example, if a block is square, tree partitioning and type partitioning can be performed. Alternatively, if the block is rectangular, a tree division can be performed.

[00139] The split setting can be determined in accordance with the encoding/decoding settings.

[00140] As an example, the division setting may be determined according to the block type. For example, in a tree partition, a quaternary tree partition can be used for the encoding block and a prediction block, and a binary tree partition can be used for the transform block. Alternatively, the permissible partition depth can be set to m in the case of a coding block, the permissible partition depth can be set to n in the case of a prediction block, and the permissible partition depth can be set to o in the case of a transform block, where m, n and o can be the same or different.

[00141] For example, the partition setting may be determined according to the block size. For example, quaternary tree partitioning can be performed for some range of the block (for example, a×b-c×d), and for some range (for example, e×f-g×h, in this example we assume that c×d is greater than g× h) Binary tree-based partitioning can be performed. In this case, the range may include all ranges from the maximum value to the minimum value of the block, and these ranges may be specified as non-overlapping with each other or as overlapping with each other. For example, the minimum value of some range may be equal to the maximum value of some range, or the minimum value of some range may be less than the maximum value of some range. In the case of overlapping ranges, the partition scheme containing the larger maximum value will take precedence. That is, in a division scheme having a certain priority, execution of a division scheme having a lower priority can be determined according to the result of the division. In this case, the range information according to the tree type may be generated explicitly or may be determined implicitly.

[00142] As another example, typed partitioning for some candidate groups may be performed in certain block ranges (same as in the example), and typed partitioning can be performed in certain ranges (same as in the example) for some candidate groups ( in the present example, at least one configuration differs from the previous group of candidates). In this case, the range may include all ranges from the maximum value to the minimum value of the block, and the range may have settings that do not overlap with each other.

[00143] As an example, the division setting may be determined according to the shape of the block. For example, if the block is square, a quaternary tree division can be performed. Additionally, if the block is rectangular, binary tree-based partitioning can be performed.

[00144] For example, the division setting may be determined according to encoding/decoding information (eg, slice type, color component, encoding mode, etc.). For example, partitioning based on a quaternary tree (or binary tree) may be performed over some range (e.g. a×b-c×d) if the slice type is I, may be performed over some range (e.g. e×f-g×h) if the type The slice type is P, and can be performed over some range (e.g. i×j-k×l) if the slice type is B. Additionally, the allowable partition depth based on a quaternary tree (or binary tree) can be set to m if the slice type is I, can be equal to n if the slice type is P, and can be equal to o if the slice type is B. Here, m, n and o may or may not be the same. Some slice types may have the same configuration as other slices (for example, P and B slices).

[00145] As another example, the allowable division depth based on a quaternary tree (or binary tree) may be set to m if the color component is a luminance component, and may be set to n if the color component is a chroma component, and m and n may or may not be the same. In addition, the division range based on a quaternary tree (or binary tree) in the case where the color component is a luminance component (eg, a×b - c×d) may or may not be the same as the division range based on a quaternary tree (or binary tree) in the case where the color component is a color-difference component (for example, e×f - g×h).

[00146] As another example, the allowable quaternary tree (or binary tree) partition depth may be equal to m if the encoding mode is intra prediction, and may be equal to n (in this example, n is assumed to be greater than m) , if the encoding mode is prediction performed between images, where m and n may or may not be the same. In addition, the partition range based on a quaternary tree (or binary tree) in the case where the encoding mode is intra prediction may or may not be the same as the partition range based on a quaternary tree (or binary tree) in the case where the encoding mode is a prediction made between images.

[00147] In the above example, adaptive configuration support information for the division candidate group according to the encoding/decoding information may be generated explicitly or determined implicitly.

[00148] Using the above example, a case in which the division mode and division setting are determined in accordance with the encoding/decoding setting is described. The above example presents some cases according to each element, and modification to other cases may be possible. In addition, the division mode and division setting can be determined according to a combination of a plurality of elements. For example, the division mode and division setting can be determined according to the type, size, shape, encoding/decoding information, etc. block.

[00149] Additionally, in the above example, elements associated with partitioning mode, setting, etc. may be defined implicitly, or this information may be generated explicitly to determine whether the adaptive case is enabled, as in the example above.

[00150] The division depth in the division setting refers to the number of times a spatial division occurs with respect to the source block (in this example, the division depth of the source block is 0), and by increasing the division depth, division into smaller blocks can be performed. The depth-related setting may vary depending on the separation pattern. For example, in tree partitioning mode, one common depth may be used for a binary tree partition depth and a ternary tree partition depth, and depending on the tree type, separate depths may be used.

[00151] In the above example, if a separate division depth is used according to the tree type, this division depth may be set to 0 at the division start position (in this example, the block before division) based on the tree. The split depth can be calculated by taking as the center the position at which the split starts, not based on the split range of each tree (in this example, the maximum value).

[00152] In FIG. 6 is a schematic diagram for explaining a tree division according to an embodiment of the present invention.

[00153] "a" represents an example of quaternary tree and binary tree partitioning. Specifically, the upper left block "a" depicts a quaternary tree-based partition, the upper right block and the lower left block depicts a quaternary tree-based and binary tree-based partition, and the lower right block depicts a binary tree-based partition. In the figure, the solid line (in this example, Quad1) represents the boundary line that splits into a quaternary tree, the dashed line (in this example, Binary1) represents the boundary line that splits into a binary tree, and the thick solid line (in this example, Binin2 ) represents a boundary line that is split into a binary tree. The difference between the dashed line and the thick solid line represents the difference in separation patterns.

[00154] As an example (the allowable partition depth based on the quaternary tree of the top left block is 3, if the current block is of size N×N, the partition is performed until one of the horizontal or vertical reaches (N>>3), and partition information is generated up to (N>>2).This also applies to the following example.The maximum and minimum values of the quaternary tree are assumed to be N×N, (N>>3)×(N>>3)), with By performing a tree division they can be divided into four blocks with 1/2 horizontal and vertical lengths. When partitioning is activated, the value of the partition flag may be "1", and when partitioning is deactivated, the value of the partition flag may be "0". According to the setting, the top left block split flag can be generated along with the top left block b.

[00155] As an example (for the top right block, the allowed quaternary tree partition depth is assumed to be 0, the allowed binary tree partition depth is 4, the maximum and minimum quaternary tree partition values are N×N, (N >>2)×(N>>2), the maximum and minimum values of the binary tree are (N>>1)×(N>>1), (N>>3)×(N>>3)), in the case performing quaternary tree division on the original block, the upper right block can be divided into four blocks with a length of 1/2 the horizontal and vertical lengths. The partitioned block size is (N>>1)×(N>>), which means that binary tree partitioning can be performed (in this example, it is larger than the minimum value of quaternary tree partitioning, but the partition depth is limited). That is, this example may be an example in which the quaternary tree-based partition and the binary tree-based partition cannot overlap. The binary tree-based partitioning information in this example can be configured using a variety of partitioning flags. Some flags may be horizontal split flags (in this example, corresponding to x in x/y), and some flags may be vertical split flags (in this example, corresponding to y in x/y). The partition flag configuration can have settings similar to quaternary tree partitioning (for example, whether to perform activation). In this example, two flags can be reactivated. If you use
"-", "-" may correspond to processing the flag implicitly. If additional partitioning cannot be performed according to conditions such as maximum value, minimum value, and tree partition depth, implicit flag processing may be generated. According to the setting, the top right block split flag can be generated together with the top left block b.

[00156] As an example (for the top left block, the allowed quaternary tree partition depth is assumed to be 3, the allowed binary tree partition depth is 2, the maximum and minimum quaternary tree partition values are N×N, (N >>3)×(N>>3), the maximum and minimum binary tree partition values are (N>>2)×(N>>2), (N>>4)×(N>>4), and in the overlapping range, the division priority is given to the quaternary tree-based division), when performing the quaternary tree-based division on the original block, the lower left block can be divided into four blocks with a length of 1/2 the horizontal and vertical lengths. The size of the partitioned block is (N>>1)×(N>>), which means that according to the settings of this example, binary tree partitioning and quaternary tree partitioning can be performed. That is, this example may be an example in which the quaternary tree-based partition and the binary tree-based partition may overlap. In this case, it may be determined to perform the binary tree partition in accordance with the result of the quaternary tree partition having a predetermined priority. When performing a quaternary tree-based partition, the binary tree-based partition will not be performed. If quaternary tree based partitioning is not performed, binary tree based partitioning can be performed. If the quaternary tree-based partitioning is not performed, even if the conditions for partitioning according to the above settings are satisfied, the quaternary tree-based partitioning may not be performed. The binary tree-based partitioning information in this example can be configured using a variety of partitioning flags. Some flags may be split flags (in this example, corresponding to x in x/y), and some flags may be split direction flags (in this example, corresponding to y in x/y, and it can be determined whether to generate y information according to with x). Partition flags can have settings similar to quaternary tree partitioning. In this example, horizontal and vertical divisions cannot be activated by overlapping each other. When generating flag information as "-" in the figure, "-" may have settings similar to the example above. According to the setting, the lower left block split flag can be generated along with the lower left block b.

[00157] As an example (for the lower right block, the allowable binary tree partition depth is assumed to be 5, the maximum and minimum binary tree partition values are N×N, (N>>2)×(N>>3 )), in case of performing a binary tree partition on the original block, the lower right block can be divided into two blocks with a length of 1/2 the horizontal and vertical lengths. The split flag setting in this example may be the same as for the lower left block. When generating flag information as "-" in the figure, "-" may have settings similar to the example above. This example depicts a case in which the horizontal and vertical minimum values of a binary tree are specified differently. According to the setting, the lower right block split flag can be generated along with the lower right block b.

[00158] As depicted in the above example, after determining the block information (eg, type, size, shape, position, cut type, color component, etc.) according to the block information, the division mode and setting can be determined separation, and the separation process can be performed accordingly.

[00159] In FIG. 7 is a schematic diagram for explaining a tree division according to an embodiment of the present invention.

[00160] Regarding block a and block b, the thick solid line L0 represents the maximum encoding block, the block divided by the thick solid line, and the other lines L1-L5 represent the divided encoding block, where the number inside the block represents the position of the divided sub-block (in this example - in raster scan order), the number of "-" characters represents the division depth of the corresponding block, and the number of the boundary line between blocks represents the number of divisions. For example, if a block is divided into four blocks (in this example, based on a quaternary tree), it has the order UL(0)-UR(1)-DL(2)-DR(3), and if the block is divided into two blocks (in this example, based on a binary tree), it has an order of L, or U(0)-R, or D(1), which can be determined at each partition depth. The following example depicts a case in which the resulting encoding blocks are limited.

[00161] As an example, it is assumed that the maximum encoding block a has a size of 64×64, the minimum encoding block has a size of 16×16, and a quaternary tree-based partition is used. In this case, since the size of blocks 2-0, 2-1 and 2-2 (in this example having a size of 16x16) is equal to the size of the minimum encoding block, they may not be subject to division into smaller blocks such as blocks 2-3 -0, 2-3-1, 2-3-2 and 2-3-3 (in this example having a size of 8x8). In this case, since there are 16×16 blocks obtained in blocks 2-0, 2-1, 2-2 and 2-3, that is, one candidate group, block division information is not generated.

[00162] As an example, it is assumed that the maximum encoding block b has a size of 64×64, the length of the minimum encoding block in the horizontal or vertical direction is 8, and the allowable division depth is 3. In this case, since the block 1-0- 1-1 (in this example having a size of 16x16 and a partition depth of 3) satisfies the minimum coding block condition, this block can be divided into smaller blocks. However, since it is equal to the allowed partition depth, this block cannot be divided into blocks having a larger partition depth (in this example, blocks 1-0-1-0-0 and 1-0-1-0-1). In this case, since there are 16×8 blocks obtained in blocks 1-0-1-0 and 1-0-1-1, that is, one candidate group, block division information is not generated.

[00163] As depicted in the above example, a quaternary tree-based partition or a binary tree-based partition can be supported in accordance with encoding/decoding. Alternatively, quaternary tree partitioning and binary tree partitioning may be supported together. For example, one or two of the above modes may be supported according to block size, partition depth, etc. If the block belongs to the first block range, a quaternary tree-based partition may be supported, and if the block belongs to a second block range, a binary tree-based partition may be supported. When supporting multiple division modes, according to each mode there may be at least one setting of the maximum encoding block size, minimum encoding block size, allowable division depth, etc. The ranges may be configured to overlap each other, or they may not overlap. Alternatively, it is also possible that a certain range includes another range. The above settings can be determined according to single or mixed factors such as slice type, encoding mode and color component.

[00164] As an example, the division setting may be determined according to the slice type. In the case of slice I, the supported partition setting is such that in the case of a quaternary tree, the supported partition range is 128x128 - 32x32, and in the case of a binary tree, the supported partition range is 32x32 - 8x8. In case of P/B slice, the supported partition setting is such that in case of quaternary tree, the supported partition range is 128x128 - 32x32, and in case of binary tree, the supported partition range is 64x64 - 8x8.

[00165] As an example, the division setting may be determined in accordance with the encoding mode. If the encoding mode is intra prediction, the supported partition setting is as follows: for a binary tree, a partition range of 64x64 - 8x8 and an allowable partition depth of 2 can be supported. If the encoding mode is inter-picture prediction, the supported partition setting is as follows: for binary tree can support a partition range of 32x32 - 8x8, and a valid partition depth of 3.

[00166] As an example, the separation setting may be determined according to the color component. For the luma component, the supported partition range is 256x256 - 64x64 in the case of a quaternary tree, and the supported partition range is 64x64 - 16x16 in the case of a binary tree. The chrominance component in the case of a quaternary tree supports the same settings as the luminance component (in this example, the length ratio of each block is set according to the chrominance format), and the supported partitioning range in the case of a binary tree is 64x64 - 4x4 (in This example assumes that this range in the same luminance component is 128x128 - 8x8, 4:2:0).

[00167] The examples describe a case in which the partition settings differ according to the block type. In addition, some blocks may be combined with other blocks to perform the partitioning process. For example, when combining an encoding block and a transform block into one element, a separation process is performed to obtain an optimal block size and shape, which may be not only an optimal encoding block size and shape, but also an optimal transform block size and shape. Alternatively, an encoding block and a transform block may be combined into one element, a prediction block and a transform block may be combined into one element, a coding block, a prediction block and a transform block may be combined into one element, and other blocks may be combined into one element.

[00168] This document describes a case in which a separate division setting is provided in each block, but it is also possible to combine multiple elements into one element having one division setting.

[00169] In the above process, the generated information will be included at the encoder in a bit stream in at least one element of a sequence, frame, slice, tile, etc., and the decoder will analyze the associated information from the bit stream.

[00170] In the image encoding/decoding process, the input pixel value may be different from the output pixel value, and a pixel value correction process may be performed to prevent distortion caused by operational errors. A pixel value adjustment scheme is the process of adjusting a pixel value that is outside the pixel value range to be within the pixel value range and can be called clipping.

Table 1

[00171] Table 1 provides example code for a clipping function (Clip_x) used to perform adjustments to a pixel value. With reference to Table 1, the input as parameters of the clipping function (Clip_x) can be the input pixel value (pixel_val), as well as the minimum value (minI) and maximum value (maxI) from the allowed range of pixel values. Here, if the description is based on bit depth (bit_depth), the minimum value (minI) may be 0, and the maximum value (maxI) may be (2bit_depth-1). When executing the clipping function (Clip_x), an input pixel value (pixel_val, parameter A) that is less than the minimum value (minI) is replaced by the minimum value (minI), and an input pixel value that is greater than the maximum value maxI (parameter C) can be replaced maximum value (maxI). Therefore, after the pixel value adjustment is complete, the output value can be returned as the pixel output value (pixel_val').

[00172] The range of pixel values is determined according to the bit depth, but the pixel values (e.g., frames, slices, tiles, blocks, etc.) that make up the image differ according to the type and characteristics of the image, so they may not be generated over the range of all pixel values. According to an embodiment of the present invention, in order for a range of pixel values to be used in an image encoding/decoding process, reference can be made to the range of pixel values that constitute the actual image.

[00173] For example, in the method for adjusting pixel values according to Table 1, the minimum value (minI) of the cut function can be used as the minimum value for the pixel values that constitute the actual image, and the maximum value (maxI) of the cut function can be used as the maximum value for the pixel values that make up the actual image.

[00174] To summarize, an image encoding/decoding apparatus may include a method for adjusting pixel values based on bit depth and/or a method for adjusting pixel values based on a range of pixel values constituting an image. The encoder/decoder may maintain flag information used to determine whether an adaptive method for adjusting pixel values can be supported. If the flag information is "1", selection information for a pixel value adjustment method can be generated, and if the flag information is "0", a preset pixel value adjustment method (in this example, a method for based on bit depth). If the pixel value adjustment method selection information indicates that the pixel value adjustment method is based on the range of pixel values that make up the image, related information about the image pixel values may be included. For example, information may be included about the minimum and maximum values of each image and the median value described below according to the color components. The information generated during the adjustment can be recorded in video, sequence, frame, slice, tile, block, etc. elements. encoder and then transmitted, and the information recorded in the decoder can be analyzed to recover related information in the same element.

[00175] On the other hand, by this process and by adjusting the pixel values based on the bit depth or adjusting the pixel values based on the range of pixel values that constitute the image, the range of pixel values including the minimum and maximum values among the pixel values can be changed (defined or given), or additional information about the range of pixel values can also be changed (defined or given). For example, the maximum and minimum values among the pixel values used to compose the actual image may be changed, and the median value used to configure the pixel values may also be changed.

[00176] That is, in the process of adjusting pixel values based on bit depth, minI may represent a minimum value of image pixels, maxI may represent a maximum value of image pixels, I may represent a color component, and medianI may represent a central value of image pixels. minI can be equal to 0, maxI can be equal to (1<<bit_depth-1)-1, midI can be equal to 1<<(bit_depth-1), and medianI can be obtained in other forms, including the examples above according to encoding/decoding settings. The median value is just a term used in the present invention for description, and it may refer to information about a range of pixel values that can be changed (determined or set) in accordance with the process of adjusting the pixel values in the image encoding/decoding process.

[00177] For example, in the process of adjusting pixel values according to a range of pixel values that make up an image, minI may represent the minimum pixel value of the image, maxI may represent the maximum pixel value of the image, and medianI may represent the central value of the image pixels. medianI may represent the average value of the pixel values in the image, may represent the value at the center when the pixels are aligned, or may represent a value obtained according to the range information of the image pixel values. For at least one of minI or maxI, medianI can be obtained. That is, medianI can represent a pixel value within a range of pixel values in the image.

[00178] In particular, medianI may be a value obtained in accordance with the image pixel value range information (in this example, minI or maxI), such as (minI+maxI)/2 or (minI+maxI)>>1 , (minI+maxI+1)/2, (minI+maxI+1)>>1, and medianI can be obtained in other forms including the above examples according to the encoding/decoding settings.

[00179] An embodiment will be described below in accordance with the processing of adjusting pixel values (in this example, the median value).

[00180] As an example, the base bit depth is 8 bits (0-255), the process of adjusting pixel values based on the range of pixel values that make up the image is selected (in this example, the minimum value is 10, the maximum value is 190, and the median value , obtained (by averaging) from the minimum and maximum values is 100), and, if the current block is the first block in the image (in this example, a frame), adjacent blocks used for encoding/decoding (in this example, the left , lower left, upper left, upper and upper right) do not exist, so the reference pixel can be filled with a median value of 100. The reference pixel can be used to perform an intra prediction process according to a prediction mode.

[00181] As an example, the base bit depth is 10 bits (0-1023), a process is selected to adjust pixel values based on the range of pixel values that make up the image (in this example, the median value is 600, and there are associated syntax elements), and , if the current block is the first block in the image (in this example, a slice or tile), the adjacent blocks used for encoding/decoding (in this example, left, bottom left, top left, top and top right) do not exist, therefore, the reference pixel may be filled with the median value of 600. The reference pixel may be used to perform an intra prediction process according to a prediction mode.

[00182] As an example, the base bit depth is 10 bits, the process of adjusting pixel values based on the range of pixel values that make up the image is selected (in this example, the intermediate value is 112, and there are associated syntax elements), setting to determine whether use the pixels of the corresponding blocks in the prediction of the current block, is activated according to the encoding mode of adjacent blocks (intra/inter-picture prediction) (in this example, if the encoding mode of the corresponding blocks is intra prediction, then it can be used for the reference pixel of the current block , and if the encoding mode is inter-image prediction, it cannot be used for the current block's reference pixel; if the setting is deactivated, it can be used as the current block's pixel regardless of the encoding mode of the corresponding blocks; a related syntax element is constrained_intra_pred_flag, which can appear in type P or B image). If the current block is located on the left side of the image, adjacent blocks used for encoding/decoding (in this example - left, lower left and upper left) do not exist, and if there are adjacent blocks used for encoding/decoding (in this example - right and top right), however, since the block encoding mode is inter-picture prediction and is disabled by the above setting, there is no reference pixel available, and then the reference pixel can be filled with the median value (112 in this example). That is, since there is no available reference pixel, it can be filled with the median value from the range of image pixel values. The reference pixel may be used to perform an intra prediction process in accordance with a prediction mode.

[00183] In the above-described embodiment, the prediction section contains various depicted cases associated with the median value, but it may be included in another video encoding/decoding configuration. Moreover, the present invention is not limited to the above-described embodiment, and modifications and extensions may be made in various cases.

[00184] In the present invention, the pixel value adjustment process may be applied to the encoding/decoding process of a prediction section, a transform section, a quantization section, an inverse quantization section, an inverse transform section, a filter section, a storage device, etc. For example, the input pixel in the pixel value adjustment method may be a reference sample value or a prediction sample value in a prediction process, and may be a reconstructed sample value in a transform, quantization, inverse transform, and inverse quantization process. In addition, the pixel may be a reconstructed sample value from an in-loop filtering process or may be a pixel stored in a storage device. In this case, in the process of transform, quantization, inverse transform, and inverse quantization, the reconstructed sampled value may refer to the reconstructed sampled value before applying filtering in the loop. The recovered sample value in the in-loop filter may refer to the recovered sample value after applying the in-loop filter. The recovered sample value during the filtering process in the deblocking filter may refer to the recovered sample value after applying the decoding filter. The recovered sampled value during the SAO process may refer to the recovered sampled value after applying the SAO. The recovered sampled value during the ALF process may refer to the recovered sampled value after applying the ALF. Examples of various cases described above have been described, but the present invention is not limited to them and can be applied to the input, intermediate and output stages of all encoding/decoding processes that cause the pixel value adjustment process.

[00185] The following example is described based on the assumption that the clipping function Clip_Y of the Y luminance components and the clipping functions Clip_Cb and Clip_Cr of the chroma components Cb and Cr are supported.

[00186] In the present invention, the prediction section can be classified into intra prediction and inter-picture prediction, and intra prediction and inter-picture prediction can be defined as follows.

[00187] Intra prediction may be a technique for generating a prediction value from a region in which encoding/decoding of the current picture (e.g., frame, slice, tile, etc.) has been completed, and prediction performed between pictures may be a technique to generate a prediction value from an image (eg frame, slice, tile, etc.) for which encoding/decoding was completed before the current image.

[00188] In addition, intra prediction may be a technique for generating a prediction value from a region in which encoding/decoding of the current picture is completed, but some prediction methods may exclude, for example, a method of generating a prediction value from a reference image, block match, pattern match and other predictions. Inter-picture prediction may be a technique for generating a prediction value from an image in which at least one encoding/decoding has been completed. The picture in which at least one encoding/decoding is completed may be configured to include the current picture.

[00189] One of the above definitions may be met according to the encoding/decoding settings, and the following example will be described assuming that the first definition is met. In addition, although the description has been made on the assumption that the prediction value is a value obtained by prediction in the spatial domain, the present invention is not limited to this.

[00190] In FIG. 8 illustrates a block division method according to an embodiment of the present invention. In more detail, this figure depicts an example of the size and shape of a block obtained in accordance with one or more division methods, starting from a basic encoding block.

[00191] In this figure, the thick solid line represents a basic coding block, the thick dashed line represents the quaternary tree-based partition boundary, the double solid line represents the symmetric binary tree-based partition boundary, the solid line represents the ternary tree-based partition boundary, and the thin dashed line the line represents the boundary of an asymmetric division based on a binary tree. With the exception of the thick solid line, each line represents a boundary divided according to each division method. The partition settings described below (eg, partition type, partition information, configuration order of partition information, etc.) are not limited to the case of the corresponding example, and various modifications may be made.

[00192] For simplicity of description, the description will be given under the assumption that separate block division settings are specified for the upper left, upper right, lower left and lower right blocks (NxN, 64x64) based on the basic encoding block (2Nx2N, 128x128). First of all, due to one division operation, four subblocks are obtained in the original block (division depth 0 -> 1, i.e. division depth increases by 1), and the maximum encoding block is 128x128, the minimum encoding block is 8x8, and the maximum division depth is 4 due to the splitting setting for the quaternary tree, which is a setting typically applied to each block.

[00193] (1 time, upper left block, A1-A6)

[00194] In this example, if a single tree-based partition is supported (in this example, a quaternary tree-based partition), the size and shape of the resulting blocks may be determined by a single block partition setting (e.g., maximum encoding block, minimum encoding block, partition depth block etc.). In this example, if a block can be obtained according to the partition (respectively dividing the width and height into two parts), the partition information required for one partition operation (based on the 4Mx4N block before partition, the partition depth is increased by 1) represents is a flag indicating whether the split is performed (in this example, if the flag is 0, x is split, and if the flag is 1, o is split). The resulting candidates can be 4M×4N and 2M×2N.

[00195] (2 times, top right block, A7-A11)

[00196] In this example, if multi-tree partitioning (quaternary tree and binary tree-based in this example) is supported, the size and shape of the resulting blocks can be determined by the multi-tree partition settings. This example assumes that in the case of a binary tree, the maximum encoding block has a size of 64x64, the minimum encoding block has a length of 4, and the maximum partition depth is 4.

[00197] In this example, if more than two blocks (2 or 4 in this example) can be obtained according to the partition, the partition information required for one partition operation (the partition depth of the quaternary tree is increased by 1) is the flag indicating whether division is being performed, a flag indicating the type of division, a flag indicating the form of division, and a flag indicating the direction of division. The resulting candidates are 4M×4N, 4M×2N, 2M×4N, 4M×N/4M×3N, 4M×3N/4M×N, M×4N/3M×4N, and 3M×4N/M×4N.

[00198] If the quaternary tree and binary tree division ranges overlap (that is, in the range where the quaternary tree division and the binary tree division can be performed at the current stage), and the current block (in the state before division) is block obtained by quaternary tree partitioning (parent block <if the partition depth is 1 less than the current partition depth> block obtained by quaternary tree partitioning), the partitioning information can be divided into the following cases. That is, if a block supported according to each partition setting can be obtained using a plurality of partition methods, partition information can be generated using the following classification.

[00199] (1) When the quaternary tree-based partition and the binary tree-based partition overlap with each other, the following occurs.

[00200] In the above table, "a" is a flag indicating whether partitioning is performed based on a quaternary tree. If this flag is 1, quaternary tree (QT) partitioning is performed. If this flag is 0, then "b" is asserted, which is a flag that indicates whether binary tree-based partitioning is performed. If b is 0, no partition is performed on the given block (no partitioning), and if b is 1, a binary tree partition is performed.

[00201] "c" is a flag indicating the direction of division, c=0 means horizontal division (hor), and c=1 means vertical division (ver). "d" denotes a flag indicating the form of division. d=0 means symmetric partitioning (SBT, symmetric binary tree), and d=1 means asymmetric partitioning (ABT, asymmetric binary tree). Only when d is 1, the detailed split ratio information (1/4 or 3/4) for asymmetric split is checked. If d is 0, in left/right or top/bottom blocks the ratio of left block to top block is 1/4, and the ratio of top block to bottom block is 3/4. If d is 1, the relationship is opposite.

[00202] (2) If only binary tree-based partitioning can be performed, the following occurs.

[00203] In the above table, partition information is expressed using flags "b" - "e" with the exception of flag "a".

[00204] In FIG. 8, the case of block A7 is a case in which the blocks (A7-A11) can be subject to quaternary tree division before division (that is, even though quaternary tree division can be performed, instead of quaternary tree division, division is performed based on a binary tree), and thus corresponds to the case in which the partitioning information is generated in step (1).

[00205] On the other hand, in the case of blocks A8-A11, if a binary tree-based partition is performed without first performing a quaternary tree-based partition in the blocks (A8-A11) before the division (that is, a quaternary tree-based partition in the corresponding blocks < A8-A11> is no longer possible), this case therefore corresponds to the case in which the division information is generated in step (2).

[00206] (3 times, lower left block, A12-A15)

[00207] In this example, a partitioning scheme based on multiple trees (in this example, a quaternary tree, a binary tree, and a ternary tree) is supported, and the size and shape of a block that can be obtained can be determined through a variety of block partitioning settings. This example assumes that in the case of binary tree/ternary tree, the maximum encoding block has a size of 64x64, the minimum encoding block has a length of 4, and the maximum partition depth is 4.

[00208] In this example, if more than two blocks can be obtained by dividing (in this example, 2, 3 and 4), the dividing information required for one dividing operation is a flag indicating whether division is performed, flag , indicating the type of split, a flag indicating the shape of the split, and a flag indicating the direction of the split. The resulting candidates are 4M×4N, 4M×2N, 2M×4N, 4M×N/4M×2N/4M×N and M×4N/2M×4N/M×4N.

[00209] If the quaternary tree and binary tree/ternary tree division ranges overlap with each other, and the current block is a block obtained by quaternary tree division, the division information may be divided into the following cases.

[00210] (1) If the quaternary tree-based partition and the binary tree/ternary tree-based partition overlap with each other, then the following occurs.

[00211] In the above table, "a" is a flag indicating whether partitioning is performed based on a quaternary tree. If this flag is 1, quaternary tree-based partitioning is performed. If this flag is 0, a flag "b" is defined indicating whether the partition is binary tree based or ternary tree based partitioned. If b is 0, no further division is performed in this block. If b is 1, binary tree partitioning or ternary tree partitioning is performed.

[00212] "c" is a flag indicating the direction of division, c=0 means horizontal division, and c=1 means vertical division. "d" is a flag indicating the type of division. d=0 means binary tree (BT) partitioning, and d=1 means ternary tree (TT) partitioning.

[00213] (2) If only binary tree/ternary tree based partitioning can be performed, the following occurs.

[00214] In the above table, partition information is expressed using flags "b" - "d" with the exception of flag "a".

[00215] In FIG. 8, the case of blocks A12 and A15 corresponds to the case in which quaternary tree-based division can be performed in blocks A12 to A15 before division, and thus corresponds to the case in which division information is generated in step (1).

[00216] On the other hand, the case of A13 and A14 corresponds to the case in which, instead of quaternary tree-based division, ternary tree-based division is performed in blocks A13 and A14 before the division, and thus corresponds to the case in which division information is generated in paragraph (2).

[00217] (4 times, lower left block, A16-A20)

[00218] In this example, a partitioning scheme based on multiple trees (in this example, a quaternary tree, a binary tree, and a ternary tree) is supported, and the size and shape of a block that can be obtained can be determined through a variety of block partitioning settings. This example assumes that in the binary tree/ternary tree case, the maximum encoding block has a size of 64x64, the minimum encoding block has a length of 4, and the maximum partition depth is 4.

[00219] In this example, if more than two blocks can be obtained by dividing (in this example, 2, 3 and 4), the dividing information required for one dividing operation is a flag indicating whether division is performed, flag , indicating the type of split, a flag indicating the shape of the split, and a flag indicating the direction of the split. Where possible, the candidates obtained are 4M×4N, 4M×2N, 2M×4N, 4M×N/4M×3N, 4M×3N/4M×N, M×4N/3M×4N, 3M×4N/M×4N, 4M ×N/4M×2N/4M×N and M×4N/2M×4N/M×4N.

[00220] If the quaternary tree and binary tree/ternary tree division ranges overlap with each other, and the current block is a block obtained by quaternary tree division, the division information may be divided into the following cases.

[00221] (1) If the quaternary tree-based partition and the binary tree/ternary tree-based partition overlap with each other, then the following occurs.

[00222] In the above table, "a" is a flag indicating whether partitioning is performed based on a quaternary tree. If this flag is 1, quaternary tree-based partitioning is performed. If this flag is 0, a "b" flag is defined indicating whether binary tree-based partitioning is performed. If b is 0, no further division is performed in this block. If b is 1, binary tree partitioning or ternary tree partitioning is performed.

[00223] "c" is a flag indicating the direction of division, c=0 means horizontal division, and c=1 means vertical division. "d" is a flag indicating the type of division. d=0 means binary tree partitioning, and d=1 means ternary tree partitioning. If d is 1, a flag "e" is defined corresponding to the shape of the split, if e is 0, a symmetric split is performed, and if e is 1, an asymmetric split is performed. If e is equal to 1, information about the detailed division relationship for asymmetric division is determined, which is similar to the previous example.

[00224] (2) If only binary tree/ternary tree based partitioning can be performed, the following occurs.

[00225] In the above table, partition information is expressed using flags "b" - "f" with the exception of flag "a".

[00226] In FIG. 8, the case of block A20 corresponds to the case in which quaternary tree-based division can be performed in blocks A16 to A19 before division, and thus corresponds to the case in which division information is generated in step (1).

[00227] On the other hand, in the case of A16-A19, since instead of a quaternary tree-based partition in blocks A16-A19, a binary tree-based partition is performed before the partition, thus this case corresponds to the case in which the partition information is generated at (2).

[00228] The intra prediction of the prediction section according to the present invention will be described below.

[00229] In FIG. 9 is an exemplary diagram showing an intra prediction mode predetermined in the image encoding/decoding apparatus.

[00230] With reference to FIG. 9, 67 prediction modes are configured as candidate prediction mode groups for intra prediction. 65 prediction modes are directional modes (2-66) and two prediction modes are non-directional modes (DC, flat). In this case, the directional mode can be divided into tilt (eg dy/dx) or angle (degrees) information. All or part of the prediction modes described in the above examples may be included in the group of luminance component or chroma component prediction candidate modes, and other, additional modes may be included in the group of candidate prediction modes.

[00231] In addition, by using the correlation between color spaces, a reconstructed block from another color space that has been encoded/decoded can be used to predict the current block, and a prediction mode that supports this can be enabled. For example, in the case of a chroma component, the reconstructed luminance component block corresponding to the current block may be used to generate a prediction block of the current block. That is, a prediction block can be generated based on the reconstructed block taking into account the correlation between color spaces.

[00232] A group of candidate prediction modes can be adaptively determined in accordance with the encoding/decoding settings. To improve the prediction accuracy, the number of candidate groups can be increased, and to reduce the number of bits according to the prediction mode, the number of candidate groups can be reduced.

[00233] For example, one group may be selected from candidate group A (67 modes, 65 directional modes, and 2 non-directional modes), candidate group B (35 modes, 33 directional modes, and 2 non-directional modes), and candidate group C (18 modes, 17 directional modes and 1 non-directional mode), and this group of candidates can be selected adaptively or determined according to the size and shape of the block.

[00234] In addition, the group of candidate prediction modes may have different configurations in accordance with the encoding/decoding settings. For example, as shown in FIG. 2, in fig. 9, a group of candidate prediction modes is configured equally for all modes, or in FIG. 9, the candidate group may be configured such that the number of modes 18 to 34 is greater than the number of modes 2 to 18. Alternatively, the opposite case may also occur and the candidate group may be configured adaptively according to the block shape (i.e., square, rectangular with long horizontal sides or rectangular with long vertical sides). For example, if the width of the current block is greater than the height, the intra prediction modes belonging to 2-15 are not used, and the intra prediction modes belonging to 67-80 can be used for replacement. On the other hand, if the width of the current block is less than the height, the intra prediction modes belonging to 53 to 66 are not used, and the intra prediction modes belonging to -14 to -1 can be used for replacement.

[00235] In the present description, unless otherwise indicated, it is assumed that intra prediction is performed using a predefined group of candidate prediction modes (candidate group A) with equal intervals between modes, however, the basic elements of the present invention can also be used to specify the above-described adaptive internal prediction after change.

[00236] In FIG. 9 may show the prediction mode supported in the case of a square or rectangular block. In addition, the prediction mode supported in the case of a rectangular block may be a prediction mode different from the above example. For example, prediction modes with different numbers of candidate prediction mode groups, or equal numbers of candidate prediction mode groups but with larger block lengths, are denser. Conversely, it may be the case that the prediction modes are diffuse, or the opposite may be the case. In the present description, as shown in FIG. 9, the prediction mode is described under the assumption that the prediction mode setting (equal intervals between directional modes) is maintained regardless of the block shape, but it is also applicable in other cases.

[00237] Various methods can be used to set the index assigned to the prediction mode. In the case of a directional mode, an index assigned to each mode can be determined based on preset priority information in accordance with the angle or slope information of the prediction mode. For example, the mode corresponding to the x-axis or y-axis (Modes 18 and 50 in Fig. 9) may have higher priority, the diagonal mode (Modes 2, 34, and 66) having an angular difference of 45 or -45 degrees based on the horizontal or vertical mode may have the following priority, diagonal mode having an angular difference of 22.5 or -22.5 degrees based on the diagonal mode may have the following priority, and the priority information can be set in this way (next - 11.25 or - 11.25 degrees, etc.) or various other ways.

[00238] Alternatively, the index may be assigned in a particular order of directions based on a predetermined prediction mode. For example, as shown in FIG. 9, the index can be assigned in a clockwise direction from a certain diagonal mode (mode 2). In the following example, the description will be made based on the assumption that the index is assigned in a clockwise direction based on a predefined prediction mode.

[00239] In addition, the undirected prediction mode may assign index information before the directed mode, or may assign index information between directed modes, or may assign index information at the end, which may be determined in accordance with the encoding/decoding settings. This example assumes that the omnidirectional mode has the highest index assignment priority among the prediction modes (it is assigned a low index, mode 0 is flat, and mode 1 is DC).

[00240] Although various examples of assigning an index to a prediction mode have been described using the above examples, the index may be assigned with other settings, the above example is not limiting, or various converted examples may occur.

[00241] In the above example, the priority information was described in terms of assigning an index to a prediction mode, but the priority information is not only used to assign an index to a prediction mode, but can also be used in the encoding/decoding process of the prediction mode. For example, the priority information may be used for MPM configuration, etc., and multiple sets of priority information may be maintained during the prediction mode encoding/decoding process.

[00242] A scheme for obtaining the intra prediction mode (in particular, the luminance component) of the current block will be described below.

[00243] The current block may use a default mode predefined in the image encoding/decoding device. The default mode may be a directional mode or an omnidirectional mode. For example, the directional mode may include at least one of a vertical mode, a horizontal mode, or a diagonal mode. The omnidirectional mode may include at least one of a planar mode or a DC mode. If it is determined that the default mode is used for the current block, the intra prediction mode of the current block may be set to the default mode.

[00244] Alternatively, the intra prediction mode of the current block can be obtained based on a plurality of MPM candidates. First, a predetermined candidate MPM may be selected from the above group of candidate prediction modes. The number of MPM candidates can be three, four, five or more. MPM candidates can be obtained based on the intra-prediction mode of contiguous blocks adjacent to the current block. An adjacent block may be a block adjacent to at least one of the left side, top end, top left end, bottom left end, or top right end of the current block.

[00245] In particular, the candidate MPM can be determined by considering whether the intra prediction mode (candIntraPredModeA) of the block at the left side and the intra prediction mode (candIntraPredModeB) of the block at the top end are the same, and whether candIntraPredModeA and candIntraPredModeB are non-directional modes.

[00246] For example, if candIntraPredModeA and candIntraPredModeB are the same, and candIntraPredModeA is not an undirected mode, the MPM candidates of the current block may include at least one of candIntraPredModeA, (candIntraPredModeA-n), (candIntraPredModeA+n), or an undirected mode. Here n may be an integer equal to 1, 2 or more. The omnidirectional mode may include at least one of a planar mode or a DC mode. For example, the MPM candidates of the current block may be determined as shown in Table 2 below. An index in Table 2 specifies, but is not limited to, the position or priority of the MPM candidates. For example, index1 may be assigned to DC mode, or index4 may be assigned.

table 2

[00247] Alternatively, if candIntraPredModeA and candIntraPredModeB are different, and candIntraPredModeA and candIntraPredModeB are not undirected modes, the MPM candidates of the current block may include at least one of candIntraPredModeA, candIntraPredModeB, (maxAB-n), (maxAB+n), or undirected mode. Here, maxAB represents the maximum value of candIntraPredModeA and candIntraPredModeB, and n may be an integer equal to 1, 2 or more. The omnidirectional mode may include at least one of a planar mode or a DC mode. For example, the MPM candidates of the current block may be determined as shown in Table 3 below. An index in Table 3 specifies, but is not limited to, the position or priority of the MPM candidates. For example, the maximum index can be assigned to the DC mode. If the difference between candIntraPredModeA and candIntraPredModeB is within the predefined threshold range, candidate MPM 1 from Table 3 will be applied, otherwise candidate MPM 2 may be applied. Here, the threshold range may be a range greater than or equal to 2 and less than or equal to 62.

Table 3

[00248] Alternatively, if candIntraPredModeA and candIntraPredModeB are different and only one of candIntraPredModeA and candIntraPredModeB is in omnidirectional mode, the current block's candidate MPMs may include at least one of maxAB, (maxAB-n), (maxAB+n), or omnidirectional mode. Here, maxAB represents the maximum value of candIntraPredModeA and candIntraPredModeB, and n may be an integer equal to 1, 2 or more. The omnidirectional mode may include at least one of a flat mode or a DC mode. For example, the MPM candidates of the current block may be determined as shown in Table 4 below. The index in Table 4 specifies, but is not limited to, the position or priority of the MPM candidates. For example, index 0 may be assigned to DC mode, or the maximum index may be assigned.

Table 4

[00249] Alternatively, if candIntraPredModeA and candIntraPredModeB are different, and both candIntraPredModeA and candIntraPredModeB are omnidirectional modes, the candidate MPMs of the current block may include at least one of omnidirectional mode, vertical mode, horizontal mode, (vertical mode-m), (vertical mode+m), (horizontal mode-m) or (horizontal mode+m). Here, m may be an integer equal to 1, 2, 3, 4 or more. The omnidirectional mode may include at least one of a flat mode or a DC mode. For example, the MPM candidates of the current block may be determined as shown in Table 5 below. The index in Table 5 specifies, but is not limited to, the position or priority of the MPM candidates. For example, index1 can be assigned to horizontal mode, or the maximum index can be assigned.

Table 5

[00250] An MPM candidate from the above plurality of MPM candidates indicated by the MPM index may be set as the intra prediction mode of the current block. The MPM index may be encoded and reported by the image encoding apparatus.

[00251] As described above, the intra prediction mode can be obtained by selectively using any of the default or candidate MPM mode. The selection may be made based on a flag reported by the encoding device. In this case, the flag may indicate whether the intra prediction mode of the current block is set as the default mode. If the flag is set to the first value, the intra prediction mode of the current block is set as the default mode, and if not, information about whether the intra prediction mode of the current block is derived from the MPM candidate, MPM index, etc. may be transmitted.

[00252] The chroma component may have the same candidate group as the luma component prediction mode candidate group, or may include a candidate group made from part of the luma component prediction mode candidate group. In this case, the group of candidate color difference component prediction modes may have a fixed configuration or a variable (or adaptive) configuration.

[00253] (Fixed Candidate Group Configuration vs. Variable Candidate Group Configuration)

[00254] As an example of a fixed configuration, as a group of chroma component prediction mode candidates, some modes in the luminance component prediction mode group are configured to perform intra prediction (for example, it is assumed that the some modes are at least one of a DC mode, planar mode, vertical mode, horizontal mode or diagonal mode <assuming that some modes are at least one of DL, UL or UR, DL is a mode in which prediction is performed from the lower right corner to the upper right corner, UL is a mode , in which prediction is performed from the upper left corner to the lower right corner, and UR is a mode in which prediction is performed from the upper right corner to the lower left corner, and it is assumed that the specified some modes are, respectively, modes 2, 34 and 66 on Fig. 9.

[00255] As an example of a variable configuration, as a basic group of chroma component prediction mode candidates, some modes are configured in the luminance component prediction candidate mode group (for example, it is assumed that these some modes are DC mode, planar mode, vertical mode, horizontal mode and UR diagonal mode, and it is assumed that more selected modes are generally configured as a core group of candidate prediction modes). However, the modes included in the candidate group may not correctly reflect the characteristics of the color difference component. To improve in this regard, the configuration of the color difference component prediction mode group can be changed.

[00256] For example, at least one prediction mode of a block or subblock of a luminance component at a position identical to or corresponding to a block of a chroma component may be included (Example 1 described below) in a basic group of candidate prediction modes, or instead of some modes may be performed a new group of candidate prediction modes (Example 2 described below). For example, in a case where the corresponding position in the luminance component corresponding to the chrominance component <according to the color format> cannot be configured with a single block, but is configured as a plurality of sub-blocks by dividing one block, a preset position block is provided. In this case, the position of the predetermined block is determined at the upper left, upper right, lower left, lower right, middle, upper middle, lower middle, left middle and right middle positions in the luminance component block corresponding to the chroma component block; if it varies to a coordinate within the image, it can be a position including the coordinate (0, 0) at the top left, a position including the coordinate (blk_width-1, 0) at the top right, a position including the coordinate (0, blk_height-1) at the bottom left, position including coordinate (blk_width-1, blk_height-1) bottom right, position including one of coordinates (blk_width/2-1, blk_height/2-1), (blk_width/2, blk_height/2-1), (blk_width/2-1, blk_height/2) and (blk_width/2, blk_height/2) in the center, a position including one of the coordinates (blk_width/2-1, 0) and (blk_width/2, 0) in the top middle, position including one of the coordinates (blk_width/2-1, blk_height-1) and (blk_width/2, blk_height-1) bottom middle, position including one of the coordinates (0, blk_height/2-1) and (0, blk_height /2) in the middle left, and a position including one of the coordinates (blk_width-1, blk_height/2-1) and (blk_width-1, blk_height/2) in the middle right. That is, it means a block including a coordinate position. The above blk_width and blk_height refer to the horizontal and vertical lengths of the luma block, and the coordinates are not limited to the above case and may include other cases. In the following description, for a luminance component prediction mode <or color mode> added to a group of chroma component prediction mode candidates, at least one prediction mode is added according to a predetermined priority <for example, assuming top left-top right-bottom left -bottom right-middle>. If two prediction modes are added, the top left block mode and the top right block mode are added according to the above settings. In this case, if the blocks in the upper left and upper right positions are configured by one block, the lower left block mode having the next priority is added.

[00257] Alternatively, the basic candidate prediction mode group may include at least one prediction mode (which may determine blocks adjacent to a block at the present position if the color difference component prediction mode candidate group includes multiple modes, blocks with a predetermined priority and subblock prediction modes with a preset priority within subblocks can be included as a set of candidates according to the priority of adjacent blocks on the left, top, top left, top right, bottom left, etc. or sub-blocks of corresponding blocks (if adjacent blocks are configured by multiple blocks), or a new group of candidate prediction modes may be configured instead of some modes.

[00258] If additional content is added to the above description, not only a prediction mode of a luminance component block or an adjacent block (luminance block) may be included, but also at least one mode derived from the prediction mode may be included as a prediction mode color difference components. The following examples will include an example in which a luminance component prediction mode is adopted as a chroma component prediction mode, and a detailed description about an example of adopting the prediction mode (for example, taking as examples the adjacent mode and the directional mode of this mode, if the horizontal mode 18 is luma component prediction mode, modes 17, 19, 16, etc. are equivalent to the derived prediction mode, and if a plurality of prediction modes are configured from the chroma component as a group of chroma component prediction modes candidate, the configuration priority of the candidate group can be set in order from the mode luminance component prediction mode to a mode derived from the luminance component prediction mode), derived from the luminance component prediction mode, or a prediction mode derived from the adjacent block prediction mode, as a group of candidate chroma component prediction modes will be omitted. However, the same or modified settings described below may apply.

[00259] As an example (1), if the luminance component prediction mode matches one of the candidate chroma component prediction mode groups, the configuration of the candidate groups is the same (the number of candidate groups does not change), and the configurations of the sample candidate groups are different if there is no match (the number of candidate groups is increasing).

[00260] If the configurations of the candidate groups in the above example are the same, the prediction mode indices may be the same, or different indices may be assigned, which may be determined according to the encoding/decoding settings. For example, if the indices of the color difference component prediction mode group are flat 0, DC1, vertical 2, horizontal 3 and diagonal UR4, in the case where the luminance component is horizontal, the configuration of the candidate prediction mode group remains unchanged, and the indices of each prediction mode remain unchanged , or other indices can be assigned (in this example, horizontal 0, flat 1, DC2, vertical 3, and diagonal UR4). The above index reset may be an example of a process performed to generate fewer mode bits during prediction mode encoding/decoding (assumption: assigning fewer bits to a small index).

[00261] If the candidate group configurations in the above examples are not the same, they may be added if the prediction mode indices can remain the same, or different indices may be assigned. For example, in the case where the index setting of the candidate prediction mode group is the same as in the previous example, if the luminance component prediction mode is diagonal DL, the configuration of the candidate prediction mode group is increased by 1, and the prediction mode index of the existing candidate group remains unchanged. Additionally, the index of the newly added mode can be used as the last one (in this example, diagonal DL5), or other indexes can be assigned (in this example, diagonal DLO, flat 1, DC2, vertical 3, horizontal 4, and diagonal UL5).

[00262] As an example (2), if the luminance component prediction mode matches one of the candidate chroma component prediction mode groups, the configuration of the candidate groups is the same (the modes of the candidate groups do not change), and the configurations of the candidate groups are different if there is no match (at least one of the candidate group modes is replaced).

[00263] If the configurations of the candidate groups in the above examples are the same, the prediction mode indices may be the same, or different indices may be assigned. For example, if the indices of the color difference component prediction mode group are flat 0, DC1, vertical 2, horizontal 3 and diagonal UR4, in the case where the luminance component prediction mode is vertical, the configuration of the candidate prediction mode group remains unchanged, and the indices of each remain unchanged prediction mode, or other indices may be assigned (in this example, vertical 0, horizontal 1, diagonal UL2, flat 3, and DC4; this example includes, but is not limited to, an example in which the directional mode precedes if the luminance component mode is directional, and an example in which the omnidirectional mode precedes in case the luminance component mode is omnidirectional).

[00264] If the configurations of the candidate groups in the above examples are different, a mode in which the prediction mode index remains unchanged remains unchanged, and a change mode may be assigned a replacement mode index, or a plurality of prediction modes may be assigned indices different from the existing index. For example, if the indices setting of the candidate prediction mode group is the same as in the previous example, in case the luminance component prediction mode is diagonal DL, one mode in the candidate prediction mode group (diagonal UL in this example) will be replaced, and the prediction mode index of the existing candidate group remains unchanged. The index of the mode to be replaced is assigned as the index (eg, diagonal DL4) of the newly added mode, or other indices may be assigned (in this example, diagonal DL0, flat 1, DC2, vertical (3), horizontal 4).

[00265] In the previous description, an example of performing index reset is given to assign fewer mode bits, but this is only an example according to the encoding/decoding settings, and other cases may occur. If the prediction mode index is not changed, a binarization may be performed in which a small number of bits is assigned to the small index, or a binarization may be performed in which the bits are assigned regardless of the size of the index. For example, if the reset prediction candidate mode group is flat 0, DC1, vertical 2, horizontal 3, and diagonal DL4, even if the diagonal DL is assigned a large index, since the diagonal DL is a mode derived from the luminance component, fewer mode bits are assigned than other prediction modes.

[00266] The prediction mode may be a mode supported in a manner independent of the picture type, or may be a mode that specifies support according to certain picture types (e.g., a mode supported by picture type I but not supported by picture type P or B Images).

[00267] The content described using the above examples is limited to the present example only, and additional or other, modified examples are possible. Additionally, the encoding/decoding settings described using the examples above may be specified implicitly, or into video elements, sequence, frame, slice, tile, etc. related information may be explicitly included.

[00268] (Receiving prediction values in the same color space versus retrieving prediction values in other color spaces)

[00269] In the case of the intra prediction mode described using the above example, the prediction mode is described with respect to a method (eg, extrapolation, interpolation, averaging, etc.) of obtaining data for generating a prediction block from adjacent regions within the same time and space.

[00270] In addition, a prediction mode may be supported with respect to a method of obtaining data to generate a prediction block from regions located within the same time and different spaces.

[00271] For example, an example of the above-described content may be a prediction mode regarding a method of obtaining data to generate a prediction block in other color spaces using correlation between color spaces. Here, when the YCbCr space is taken as an example, the correlation between color spaces may represent the correlation between Y and Cb, Y and Cr, Cb and Cr. That is, in the case of the chroma difference component Cb or Cr, the reconstructed luminance component block corresponding to the current block can be generated as a prediction block of the current block (the basic setting of the following example is chroma difference versus luminance). Alternatively, the reconstructed block of some color difference components (Cb or Cr) corresponding to the current block of some color difference components (Cr or Cb) may be generated as a color difference component (Cr or Cb) prediction block. In this case, the reconstructed block of other color spaces can be directly generated as a prediction block (i.e., without performing correction), or as a prediction block, a block obtained taking into account the correlation between colors can be generated (for example, an existing reconstructed block is subject to correction using the formula P=a*R+b, where a and b represent the correction values, R and P respectively represent the values obtained in other color spaces and the prediction values of the current color space).

[00272] In this example, the description is made under the assumption that data obtained using color space correlation is used as a prediction value of the current block, but it is also possible in the case where the data is used as a correction value to correct the prediction value of an existing current block (eg, residual values of other color spaces are used as correction values; that is, there are other prediction values and these prediction values are corrected; and although these prediction values are added to obtain a prediction value as well, the description is made to distinguish in detail). The present description is intended to describe the first case, but the present invention is not limited to it, and the correction values can be used in a similar or variable manner.

[00273] The prediction mode may be a mode supported in a manner independent of the picture type, or may be a mode that specifies support according to certain picture types (e.g., a mode supported by picture type I but not supported by picture type P or B Images).

[00274] (Comparison with obtaining related information)

[00275] In the above example, the correlation information (a, b, etc.) between color spaces may explicitly include related information, or it may be obtained implicitly. Here, the comparison region for obtaining related information may be 1) a current chroma component block and a corresponding luminance component block, or 2) an adjacent region (e.g., left block, top block, top left block, top right block, bottom left block, etc.) .d.) of the current block of the color-difference component and the adjacent area of the corresponding block of the brightness component. The present example is an example in which the former can be expressed explicitly and the latter can be expressed implicitly.

[00276] For example, related information is obtained by comparing at least one pixel value of each color space (in this case, the pixel value to be compared may be a pixel value obtained from one pixel in each color space, and may be a pixel value obtained from many pixels). Pixel values obtained from a filtering process by weighted averaging or the like, that is, the number of pixels that are reference or used to compare one pixel value of each color space, may be one pixel versus one pixel, one pixel versus many pixels or the like. In this case, the former may be a color space for generating the prediction value, and the latter may be a reference color space. The above example may be possible according to the color format, or the pixel value for one chroma component pixel can be compared with the pixel value for the corresponding luminance component pixel in a manner independent of the color format, the pixel value for one chroma component pixel can be compared to the pixel value , obtained by performing a filter <a-tapseparate1Dfilter, bxcmasknon-separable2Dfilter, d-tapdirectionalfilter, etc.> on a set of luminance component pixels, and either of these two methods can be used according to the encoding/decoding settings. Examples of color difference and brightness have been described above, but converted examples such as color difference <Cb> and color difference <Cr> may also occur.

[00277] In the above example, the comparison region, if the associated information is obtained implicitly, may be the nearest line of pixels of the current block of the current color component (e.g., pixels including p[-1, -1] to p[blk_width-1, -1], from p[-1, 0] to p[-1, blk_height-1]), and the corresponding pixel lines of other color spaces or the set of pixel lines of the current block of the current color component (for example, in the above case, the pixels included in a plurality of pixel lines including p[-2, -2] to p[blk_width-1, -2], p[-2, -1] to p[-2, blk_height-1], and corresponding pixel lines of other color spaces.

[00278] In particular, assuming that the color format is 4:2:0, the pixel value for one pixel in the current color space (in this example, the color difference) can be used to compare the pixel value for one pixel in a predefined position (in this example selected from top left, top right, bottom left and bottom right within 2×2) in 4 corresponding pixels (one pixel of the chroma component corresponds to 4 pixels within 2×2 luminance components) in other color spaces (in in this example - bit brightness). Alternatively, to compare the pixel value for one pixel in chroma space, a pixel value obtained by performing filtering on a plurality of pixels (eg, at least two pixels in corresponding 2x2 pixels, etc.) in luma space may be used.

[00279] To summarize, parameter information can be obtained from reconstructed pixels in the adjacent region of the current block and reconstructed pixels in other corresponding color spaces. That is, based on the associated information, at least one parameter can be generated (for example, a or b, a1, b1 or a2, b2, etc.), and it can be used as a value that is multiplied by or added to the pixels reconstructed blocks in other color spaces (for example, a, a1, a2/b, b1, b2).

[00280] In this case, comparison processing may be performed after determining the availability of the pixels subjected to comparison in the above example. For example, if the adjacent region is available, it can be used as a pixel for comparison, and if the adjacent region is not available, it can be determined according to the encoding/decoding settings. For example, if a pixel in an adjacent region is not available, it may be excluded from the process of obtaining associated color space information, or it may be included in the comparison process after filling the inaccessible region, which may be determined in accordance with the encoding/decoding settings.

[00281] For example, by excluding the process of obtaining correlation information between color spaces, this example may be an example corresponding to a case in which a region containing pixels of at least one color space is inaccessible. In detail, this may be an example corresponding to a case in which pixels of one of two color spaces are not available, or pixels of two color spaces are not available, which can be determined according to the encoding/decoding settings.

[00282] Alternatively, if the process of obtaining correlation information between color spaces is performed after padding the comparison data in the inaccessible region (or an operation similar to the process of padding a reference pixel), various padding methods may be used. For example, a predefined pixel value (for example, the median value 1 of bit_depth << (bit_depth-1), the value between the minimum and maximum values of the actual image pixel, the average of the actual image pixel, the median value, etc.) can be used for padding. , adjacent pixels or a value obtained by performing filtering (an operation similar to the process of filtering reference pixels) on adjacent pixels may be used for padding, or other methods may be used.

[00283] In FIG. Figure 10 shows an example of comparing pixels from different color spaces to obtain correlation information. For ease of description, it is assumed that the color format is 4:4:4. In this case, the following process is described according to the component ratio of a color format (ie, a process including a conversion process based on the component ratio).

[00284] R0 represents an example in which color space regions on both sides can be used. Since the accessible regions are regions of the color space on both sides, the comparison process can use pixels in the corresponding regions to obtain related information.

[00285] R1 represents an example in which one of the regions of the color space on both sides is inaccessible (in this example, the adjacent region of the current color space is accessible, while the corresponding regions of the other color spaces are inaccessible). The inaccessible areas can be used for the comparison process after using various methods to fill the inaccessible areas.

[00286] R2 represents an example in which one of the color space regions on both sides is inaccessible (in this example, the adjacent region of the current color space is inaccessible, while the corresponding regions of other color spaces are accessible). Since there is an inaccessible area on one side, the corresponding areas of the two color spaces cannot be used in the comparison process.

[00287] R3 represents an example in which regions of the color space on both sides are not available. Inaccessible areas are filled using various methods and can be used for the comparison process.

[00288] R4 represents an example in which regions of the color space on both sides are not available. Since there are inaccessible areas on both sides, the corresponding color space areas on both sides cannot be used in the comparison process.

[00289] In addition, unlike FIG. 10, if adjacent areas of the current block or corresponding areas of other color spaces are not available, various adjustments can be made.

[00290] As an example, a and b may be assigned predefined values (in this example, a is 1 and b is 0). This case may involve maintaining a mode in which data in a different color space is filled by the current block's prediction block. In addition, a given case may allow, when performing prediction mode encoding/decoding, that the setting or priority of the probability of occurrence (or selection) of the mode has a setting different from the existing case (for example, the selection probability is set to less high, or the priority is set to less high ; in other words, due to the low accuracy of the related information, the accuracy of the prediction block obtained by a given prediction mode may be very low, so it is estimated that the mode will not be selected as the optimal prediction mode).

[00291] For example, since there is no data to compare, the mode of filling another color space data with the prediction block of the current block may not be supported. That is, this mode may be a mode supported when at least one region is available. In this case, when encoding/decoding of the prediction mode is performed, it can be configured to allow or not to allow the mode to be replaced by other modes. The first case may be a setting in which the number of candidate prediction mode groups is maintained, and the last case is a setting in which the number of candidate prediction mode groups is reduced.

[00292] The present invention is not limited to the above examples, and various converted examples may also occur.

[00293] In the above example, the inaccessibility case is the case in which the region is outside the boundaries of the image (e.g., frame, slice, tile, etc.) (that is, the current block and region are not included in the same image), if the region was not encoded/decoded. For example, the unavailability case can be added according to the encoding/decoding settings (for example, constrained_intra_pred_flag, etc., for example, if the type is slice P or B, the above flag is 1, and the encoding mode of the corresponding region is inter-picture prediction ).

[00294] In the following example, the above limitation may occur when generating a prediction block of the current block using reconstructed data from other color spaces after obtaining related information by comparing two color spaces. That is, as described above, if it is determined that corresponding regions of other color spaces corresponding to the current block are not available, the use of this mode may be limited or this mode is unavailable.

[00295] To generate the prediction value of the current block, a parameter representing the correlation information between color spaces obtained by the above process and the reconstructed data of other color spaces corresponding to the current block can be used. In this case, the reconstructed other color space data used to predict the current block may be a pixel value for a pixel at a predetermined position or a pixel value obtained through a filtering process.

[00296] For example, in the case of 4:4:4, to generate the prediction value of one pixel in chroma space, the pixel value for the corresponding pixel in luma space can be used. Alternatively, to generate a prediction value of a single pixel in chroma space, pixel values obtained by filtering multiple pixels in luminance space (e.g., pixels in directions such as left, right, up, down, up left, up right, down left) may be used. and down to the right by centering on the corresponding pixel, if, as examples, 5-tap and 7-tap filters are used, it is understood that there are two pixels and three pixels specifically in the left, right, up and down directions, respectively, by centering on corresponding pixel).

[00297] For example, in the case of 4:2:0, to generate a prediction value of one pixel in chroma space, the pixel value for one pixel at a predetermined position (selected from top left, top right, bottom left, and bottom right) can be used from four corresponding pixels (one chrominance component pixel corresponds to 2x2 luminance component pixels) in luminance space. Alternatively, pixel values obtained by filtering a plurality of pixels (e.g., at least two pixels in corresponding 2x2 pixels or pixels in directions such as left, right, up, down, up left, up right, down left and down right, by centering on 2x2 pixels in luminance space.

[00298] To summarize, to obtain a pixel value used as a pixel prediction value in the current color space, a parameter representing information can be applied (by multiplication or addition, etc.) to the pixel value obtained in other color spaces o the correlation obtained using the above process.

[00299] In the above example, some color formats, some processes for obtaining pixel values, etc. have been described, but the present invention is not limited to them, and the same or modified examples may be used in other cases.

[00300] The described content (obtaining prediction values in one color space versus obtaining prediction values in different color spaces) may be applied to a fixed candidate group configuration versus a variable candidate group configuration. For example, if the prediction value cannot be obtained in other color spaces, a prediction value replacement mode may be included in the candidate group.

[00301] Using the above example, in the case of the prediction mode described above, related information (eg, support or lack thereof information, parameter information, etc.) may be included in the image, sequence, frame, slice and tile elements.

[00302] To summarize, a prediction mode (Mode A) associated with a method (the above method is a method for obtaining data for generating prediction blocks from adjacent regions within the same time and space according to the encoding/decoding settings) is used for configuring group of candidate prediction modes, or, in addition to the prediction mode, the group of candidate prediction modes may include a prediction mode (Mode B) associated with a method (the above method is a method of obtaining data for generating prediction blocks from regions located within the same time and different spaces).

[00303] In the above example, the candidate prediction mode group can be configured using only mode A or only mode B, and the candidate prediction mode group can be configured by combining mode A and mode B. Information about the configuration settings of the candidate mode group The prediction data may be explicitly generated in a correlation manner, or the configuration information of a group of candidate prediction modes may be implicitly determined in advance.

[00304] For example, groups of candidate prediction modes may have one configuration regardless of any encoding/decoding settings (in this example, picture types) or have one configuration in accordance with some encoding/decoding settings (e.g., mode A, mode B_1<color mode> and mode B_2<color copy mode> are used to configure a candidate prediction mode group in image type I, mode A and mode B_1 are used to configure a candidate prediction mode group in image type P, and mode A and mode B_2 are used to configure a group of candidate prediction modes in picture type B).

[00305] In the present description, a group of candidate prediction modes for the luminance component is depicted in FIG. 9, and it is assumed that the group of candidate prediction modes for the color difference component is configured as horizontal, vertical and diagonal modes in FIG. 9 (flat, DC, color mode 1, color mode 2, color mode 3, color copy mode 1, color copy mode 2, adjacent block mode 1 (left block), adjacent mode 2 (top block)), however may also have other settings for different groups of candidate prediction modes.

[00306] In the image encoding method according to an embodiment of the present invention, intra prediction can be performed as follows. The intra prediction of the prediction section may comprise a reference pixel configuration step, a prediction block generation step, a prediction mode determination step, and a prediction mode encoding step. In addition, the image encoding apparatus may be configured to include a reference pixel configuration section, a prediction block generating section, and a prediction mode encoding section to implement the reference pixel configuration step, the prediction block generation step, the prediction mode determining step, and the prediction mode encoding step. Some steps of the above process may be omitted, or other steps may be added and their order may be changed to other orders than the above order.

[00307] Moreover, in the image decoding method according to an embodiment of the present invention, intra prediction can be performed as follows. The intra prediction of the prediction section may include a prediction mode decoding step, a reference pixel configuration step, and a prediction block generation step. In addition, the image decoding apparatus may be configured to include a prediction mode decoding section for implementing the prediction mode decoding step, a reference pixel configuration section for implementing the reference pixel configuration step, and a prediction block generation section for implementing the prediction block generation step. Some of the above steps may be omitted, or other steps may be added and their order may be changed to different orders from the above order.

[00308] In the prediction block generation step, intra prediction may be performed on an element of a current block (eg, an encoding block, a prediction block, a transform block, etc.) or intra prediction may be performed on an element of a predetermined subblock. For this purpose, a flag may be used to indicate whether the current block is divided into subblocks to perform intra prediction. This flag may be encoded and reported by the encoder. If the flag is equal to the first value, the current block is divided into many subblocks, otherwise the current block is not divided into many subblocks. In this case, the division may be an additional division made after the division based on the above-described tree structure. Subblocks belonging to the current block share the same intra prediction mode, but different reference pixels can be configured for each subblock. Alternatively, the subblocks may use the same intra prediction mode and the same reference pixels. Alternatively, the subblocks may use the same reference pixels, but different intra prediction modes may be used for each subblock.

[00309] The division can be done in a vertical or horizontal direction. The dividing direction may be determined based on a flag reported by the encoding device. For example, if the flag is set to the first value, the division may be performed in the horizontal direction, otherwise the division may be performed in the vertical direction. Alternatively, the direction of division may be determined based on the size of the current block. For example, if the height of the current block is greater than a predetermined threshold value, division may be performed in the horizontal direction, and if the width of the current block is greater than a predetermined threshold value, division may be performed in the vertical direction. Here, the threshold value may be a fixed value predetermined in the encoding/decoding apparatus, or the threshold value may be determined based on block size information (eg, maximum transform block size, maximum encoding block size, etc.). Block size information may be reported at at least one sequence, frame, slice, tile, block, or CTU line level.

[00310] The number of subblocks may be variably determined based on size, shape, partition depth, intra prediction mode, etc. current block. For example, if the current block is 4x8 or 8x4, the current block can be divided into two subblocks. Alternatively, if the current block has a size greater than or equal to 8x8, the current block may be divided into four subblocks.

[00311] The present description will mainly describe the encoder. In the case of a decoder, detailed description regarding the decoder is omitted since it can be obtained from the contents of the encoder in reverse order.

[00312] In FIG. 11 is a circuit diagram for explaining the configuration of reference pixels for intra prediction. The size and shape (M×N) of the current block used for prediction can be obtained from the block division section and will be described based on the assumption that intra prediction is supported within the range of 4×4 - 128×128. In general, intra prediction may be performed using a prediction block element, however, according to the settings of the block division section, intra prediction may be performed on encoding block elements and transform block elements. After confirming the block information, the reference pixel configuration section may configure a reference pixel used for predicting the current block. In this case, the reference pixel processing may be performed by a temporary storage device (such as an <Array>, a main array or a auxiliary array, etc.), a reference pixel may be generated and deleted during each block intra prediction process, and the size of the temporary storage device can be determined according to the configuration of the reference pixel.

[00313] This example is described based on the assumption that a left block, a top block, a top left block, a top right block, and a bottom left block are used to predict the current block by centering on the current block. However, it is not limited to this, and a group of candidate blocks having other configurations can be used to predict the current block. For example, a candidate group for adjacent reference pixel blocks may be exemplified according to a raster or Z-scan, and part of the candidate group may be removed according to the scanning order, or the candidate group may be configured to include other candidate block groups ( for example, additional configuration of top block, bottom block, bottom right block, etc.).

[00314] Alternatively, blocks (e.g., having corresponding coordinates according to the same coordinate or component compositional relationship in each color space) corresponding to the current block in other color spaces (e.g., if the current block belongs to Cr, other color spaces) may be used to predict the current block spaces correspond to Y or Cb). In addition, for ease of description, the description is made on the assumption that the predetermined position (left, top, top left, top right and bottom left) is configured as one block, but at least one block may exist at the corresponding position. That is, at a predetermined position according to the corresponding block, a plurality of subblocks of the separating block may exist.

[00315] To summarize, the adjacent region of the current block may be the position of a reference pixel for intra prediction of the current block, and the position of the reference pixel according to the prediction mode may be considered the region corresponding to the current block of another color space. In addition to the above examples, a position of a reference pixel set according to a prediction mode, method, etc. can be determined. For example, if a prediction block is generated in a manner such as block matching, the position of the reference pixel may be considered to be the region in which encoding/decoding was completed before the current block of the current image, or the region included in the search range in the region where encoding/decoding was completed (for example included on the left side, or the top side, or the top left side and the top right side of the current block).

[00316] As shown in FIG. 11, a reference pixel for predicting the current block can be configured by adjacent pixels of the left block, top block, top left block, top right block and bottom left block (Ref_L, Ref_T, Ref_TL, Ref_TR and Ref_BL in FIG. 11). In this case, the reference pixel generally consists of the adjacent block pixels closest to the current block (a in FIG. 11), but may also include other pixels (pixels on b and other outer lines in FIG. 11). That is, at least one of a first pixel line a adjacent to the current block, a second pixel line b adjacent to the first pixel line, a third pixel line adjacent to the second pixel line, or a fourth pixel line adjacent with a third line of pixels. For example, according to the encoding/decoding settings, the plurality of pixel lines may include all of the first to fourth pixel lines, or may include only the remaining pixel lines excluding the third pixel line. Alternatively, the plurality of pixel lines may include only the first pixel line and the fourth pixel line.

[00317] The current block may perform intra prediction by selectively referring to any of a plurality of pixel lines. In this case, the selection may be made based on the index (refIdx) reported by the encoding device. Alternatively, any of the plurality of pixel lines may be selectively used based on the size, shape and division type of the current block, whether the intra prediction mode is an omnidirectional mode, the angle of the intra prediction mode, etc. For example, if the intra prediction mode is planar mode or DC mode, only the first line of pixels may be used. Alternatively, only the first line of pixels may be used if the size (width or height) of the current block is less than or equal to a predefined threshold. Alternatively, only the first line of pixels may be used if the intra prediction mode is greater than a predetermined threshold angle (or less than a predetermined threshold angle). The threshold angle may be an intra prediction mode angle corresponding to mode 2 and mode 66 of the above group of candidate prediction modes.

[00318] On the other hand, pixels adjacent to the current block can be classified as at least one layer of reference pixels, which can be classified such that the pixels closest to the current block are ref_0 (pixels having a pixel value difference equal to 1, relative to the boundary pixel of the current block; from p(-1, -1) to p(2m-1, -1), from p(-1, 0) to p(-1, 2n-1)), next adjacent pixel (the difference between the boundary pixel of the current block and the pixel value is 2; from p(-2, -2) to p(2m, -2), from p(-2, -1) to p(-2, 2n) ) represents ref_1, and the next adjacent pixel (the difference between the boundary pixel of the current block and the pixel value is 3; from p(-3, -3) to p(2m+1, -3), from p(-3, -2 ) to p(-3, 2n+1)) represents ref_2, etc. That is, a reference pixel can be classified into a plurality of reference pixel layers according to distances of pixels that are adjacent to a boundary pixel of the current block.

[00319] Additionally, the reference pixel layers may be arranged differently for each adjacent block. For example, a reference pixel according to layer ref_0 can be used when a block adjacent to the current block and a block adjacent to the top end are used as reference blocks, and a reference pixel according to layer ref_1 can be used when a block adjacent to top end.

[00320] In this case, the set of reference pixels that are typically referred to when performing intra prediction belongs to contiguous blocks adjacent to the current block. Adjacent blocks are located at the bottom left, left, top left, top end and top right end and represent pixels belonging to the ref_0 layer (pixels closest to the boundary pixel), and pixels belonging to each other are considered to be these pixels if not otherwise stated. However, only a portion of the pixels belonging to the above-mentioned adjacent blocks may be used as a set of reference pixels, or pixels belonging to more than two layers may be used as a set of reference pixels. In this case, the set, or layer, of reference pixels may be defined implicitly (preset in the encoding/decoding apparatus) or may be explicitly defined (the determination information may be received from the encoding apparatus).

[00321] The present description is made on the basis that the maximum number of reference pixel layers supported is 3, but it may also have a value that is greater than this number, and the number of reference pixel layers and the number of reference pixel sets according to the positions of adjacent blocks, to which may be referred to (or which may be called candidate reference pixel groups) may be specified differently according to the size, shape, prediction mode, image type (I/P/B, in this case the image is a frame, slice, tile etc.), color component, etc. block, and related information can be included in sequence, frame, slice, tile, etc. elements.

[00322] The present invention is described under the assumption that the subscript (incremented by 1 from 0) is assigned from the reference pixel layer closest to the current block, but the present invention is not limited to this. In addition, related reference pixel configuration information described below may be generated by adjusting the indices as described above (binarization of assigning a short bit to a subscript when one of a plurality of reference pixel sets is selected, etc.).

[00323] In addition, if there are more than two supported reference pixel layers, each reference pixel included in more than two reference pixel layers can be used for weighted averaging.

[00324] For example, a prediction block may be generated using a reference pixel obtained from a weighted sum of pixels located in the ref_0 layer (nearest pixel layer) and the ref_l layer (next pixel layer) according to FIG. 11. In this case, according to the prediction mode (eg, the directional prediction mode), the pixels to which the weighted sum is applied in each reference pixel layer may be not only integer element pixels, but also decimal element pixels. In addition, to obtain the prediction block, weighted values (for example, 7:1, 3:1, 2:1 and 1:1) are respectively applied to the prediction block obtained by using the reference pixels according to the first reference pixel layer, and a prediction block obtained by using reference pixels in accordance with the second reference pixel. In this case, if the weighted value is a prediction block according to a reference pixel layer adjacent to the current block, the weighted value may be higher.

[00325] In general, for the above example, it is possible to use the nearest pixel from an adjacent block as the reference pixel, but is not limited to this. For example, there may be various cases (for example, a case in which ref_0 and ref_1 are selected as reference pixel layers, and ref_0 and ref_1 are used to perform weighted summation and other methods of generating prediction pixel values, etc., i.e. implicit happening).

[00326] In addition, associated reference pixel configuration information (e.g., selection information for a layer, or set, of reference pixels, etc.) may not include preset information (e.g., if the reference pixel layer is preset as ref_0) . For example, it may be configured as, but not limited to, ref_1, ref_2, ref_3, etc.

[00327] Some cases of reference pixel configurations have been described using the above examples, which can be combined with various encoding/decoding information, etc. to define intra prediction settings. In this case, the encoding/decoding information contains the image type, color component, shape and size of the current block, prediction mode (prediction mode type (directional or omnidirectional)), prediction mode direction (vertical, horizontal, diagonal 1, diagonal 2, etc.). etc.), etc., and the intra prediction settings (in this example, the reference pixel configuration settings) can be determined in accordance with the encoding/decoding information of the adjacent block and the combination of the encoding/decoding information of the current block and the adjacent block.

[00328] In FIG. 12 is a circuit diagram for explaining the range of a reference pixel for intra prediction. In detail, the range of the reference pixel is determined according to the block size and shape, the prediction mode configuration (in this example, the prediction mode angle information), etc. The position indicated by the arrow in Fig. 12 is a pixel used for prediction.

[00329] With reference to FIG. 12, pixels A, A', B, B' and C refer to the pixels at the lower right end of the 8×2, 2×8, 8×4, 4×8 and 8×8 blocks. To perform pixel prediction, the reference pixel range of each block can be determined using the AT, AL, BT, BL, CT and CL pixels used in the top and left blocks.

[00330] For example, if the reference pixels are pixels A and A' (rectangular blocks), they are located within the range from p(0, -1) to p(9, -1), from p(-1, 0) to p(-1, 9), p(-1, -1), if the reference pixels are pixels B and B' (rectangular blocks), they are located within the range from p(0, -1) to p(11, - 1), p(-1, 0) to p(-1, 11), p(-1, -1), and if the reference pixel is pixel C (square block), it is located within the range of p( 0, -1) to p(15, -1), from p(-1, 0) to p(-1, 15), p(-1, -1).

[00331] Range information (e.g., P(-1, -1), P(M+N-1, -1), P(-1, N+M-1), etc.) of the reference pixel, obtained by the above process can be used for an intra prediction process (eg, a reference pixel filtering process, a reference pixel generation process, etc.). In addition, support for reference pixels is not limited to the above-described cases, and various other cases are also possible.

[00332] The reference pixel configuration section for intra prediction may include a reference pixel generation section, a reference pixel interpolation section, a reference pixel filtering section, etc. and may have all or part of the above configurations.

[00333] The reference pixel configuration section is configured to check the availability of reference pixels to classify available reference pixels and unavailable reference pixels. For example, if a block at a predetermined position (or a reference pixel candidate block) can be used, then the corresponding block can be used as a reference pixel, and if it is not available, that block cannot be used as a reference pixel.

[00334] If at least one of the following conditions is satisfied, it is determined that the reference pixel is unavailable. For example, a reference pixel is defined as unreachable if one of the conditions is satisfied that the reference pixel is outside the frame boundary, the reference pixel does not belong to the same division block as the current block (e.g. slice, tile, etc.), encoding/decoding is not completed and the reference pixel usage is limited according to the encoding/decoding setting. That is, if none of the above conditions are satisfied, it is determined that the reference pixel is available.

[00335] In addition, the use of reference pixels may be limited by encoding/decoding settings. For example, the use of reference pixels may be constrained in accordance with the performance of constrained intra prediction (eg, constrained_intra_pred_flag). Limited intra prediction may be performed when error-tolerant encoding/decoding needs to be performed with respect to external factors, such as the communication environment, if an attempt is made to prohibit the use of blocks reconstructed by referring to other images as reference pixels.

[00336] If constrained intra prediction is deactivated (for example, in frame type I or frame type P or B constrained_intra_pred_flag=0), all candidate reference pixel blocks are available, and if enabled (for example, in frame type P or B constrained_intra_pred_flag=1), the use of a reference pixel from the corresponding block may be determined in accordance with the encoding mode (intra prediction or inter-picture prediction) of the reference pixel candidate block. That is, if the coding mode of a block is intra prediction, the block can be used regardless of whether limited intra prediction is enabled. In the case of inter-picture prediction, the availability (deactivated) or unavailability (activated) of a block is determined depending on the activation of the limited intra prediction.

[00337] In addition, limited intra prediction may be applied in accordance with the encoding mode of the reconstructed block corresponding to the current block in another color space. For example, the current block belongs to some chroma components Cb and Cr, and the availability of limited intra prediction is determined according to the block coding mode in which encoding/decoding of the luminance Y component corresponding to the current block is completed. The above example may be an example of a case in which a reconstructed block of a different color space is used as a reference pixel. Moreover, it may be an example of a case in which the encoding mode is determined independently according to the color space.

[00338] In this case, if a reference pixel candidate block is encoded/decoded by some prediction methods (for example, prediction by block matching or pattern matching in the current image), the use of that reference pixel can be determined according to the encoding/decoding settings .

[00339] As an example, if encoding/decoding is performed using a specified prediction method, and if the encoding mode is set to intra prediction, the corresponding block may be determined to be available. Alternatively, even if intra prediction is used, special cases are allowed in which the block is unavailable.

[00340] For example, if encoding/decoding is performed using a specified prediction method, and if the encoding mode is set to inter-picture prediction, the corresponding block may be determined to be unavailable. Alternatively, even if cross-picture prediction is used, special cases in which a block is available are allowed.

[00341] That is, according to the encoding/decoding settings, it can be determined whether to make an exception for the case of determining use according to the encoding mode.

[00342] Limited intra prediction may be a setting applied to certain image types (eg, slice/tile types P or B, etc.).

[00343] According to the availability of a reference pixel, candidate reference pixel blocks can be classified into a case in which all candidate reference pixel blocks can be used, a case in which some reference pixels can be used, and a case in which all reference pixels not available. Except in the case in which all reference pixel candidate blocks may be used, in all other cases reference pixels not available at the candidate block position may be filled or generated.

[00344] If a reference pixel candidate block is available, a pixel at a predetermined position of that block (in this example, the pixel is assumed to be adjacent to the current block) can be stored in the reference pixel memory of the current block. In this case, the pixel data from the position of the corresponding block can be stored in the reference pixel memory by processes such as direct copying or reference pixel filtering.

[00345] If a reference pixel candidate block is not available, pixels obtained by the reference pixel generation process may be stored in the reference pixel memory of the current block.

[00346] Briefly, if a reference pixel candidate block is in an available state, a reference pixel can be configured, and if a reference pixel candidate block is in an unavailable state, a reference pixel can be generated.

[00347] The following are examples of the use of various methods for filling reference pixels at inaccessible block positions.

[00348] For example, an arbitrary pixel value may be used to generate a reference pixel, and there may be a pixel value belonging to a range of pixel values (e.g., a value obtained from a bit depth-based pixel value adjustment process or an information-based pixel value adjustment process about the range of values of an image pixel, such as minimum value, maximum value and median value). In more detail, this may be an example applicable when all reference pixel candidate blocks are not available.

[00349] Alternatively, reference pixels may be generated upon completion of image encoding/decoding. More specifically, reference pixels may be generated from at least one available block adjacent to the inaccessible block. In this case, at least one of extrapolation, interpolation, copying or other methods may be used, and the direction of generating (or copying and extrapolating) reference pixels may be a clockwise or counterclockwise direction, and it may be determined in accordance with encoding/decoding settings. For example, the direction of generating reference pixels in a block may be a predetermined direction or a direction adaptively determined according to the position of an inaccessible block. Alternatively, for the region corresponding to the current block in other color spaces, the same method as in the example above can be used. The difference is that while the process of filling adjacent reference pixels of the current block is performed in the current color space, the process of filling the M×N block corresponding to the current m×n block is performed in other color spaces. Therefore, various other methods can be used to generate the corresponding regions, including the above method (for example, extrapolation in the vertical, horizontal and diagonal directions of the surrounding pixels, planar interpolation, averaging, etc., in this case, the filling direction refers to the direction from the surrounding pixels of the block corresponding to the current block, inside the block). This example may be a case in which a prediction mode used to generate a prediction block from another color space is included in the candidate group, but is not excluded from the candidate group.

[00350] In addition, after completing the configuration of reference pixels, reference pixels in decimal units can be generated by a process of confirming the availability of reference pixels by linear interpolation of the reference pixels. Alternatively, the reference pixel interpolation process may be performed after the reference pixel filtering process is performed. Alternatively, only the filtering process may be performed on the configured reference pixels. Briefly, it may be executed before the prediction block generation process.

[00351] In this case, in horizontal mode, vertical mode, some diagonal modes (for example, bottom-right diagonal, bottom-left diagonal, and top-right diagonal) and omnidirectional modes, color mode, color copy mode, etc. no interpolation process is performed, but in case of other modes (other diagonal modes), interpolation may be performed.

[00352] The interpolation accuracy can be determined according to the supported group of candidate prediction modes (or the total number of prediction modes), the configuration of the prediction mode (eg, the direction angle of the prediction mode and the interval between prediction modes), etc.

[00353] To interpolate the reference pixels in the decimal element, a predefined filter (e.g., 2-tap linear interpolation filter) may be used, and one of a variety of candidate filter groups may be used (e.g., 4-tap cubic filter, 4-tap Gaussian filter, 6-tap Wiener filter, 8-tap Kalman filter).

[00354] If one of a plurality of candidate filter groups is used, filter selection information may be generated explicitly or determined implicitly and may be determined in accordance with encoding/decoding settings (e.g., interpolation precision, block size and shape, prediction mode etc.).

[00355] For example, the interpolation filter to use may be determined according to the block size range, the interpolation filter to use may be determined according to the interpolation precision, and the interpolation filter may be determined according to characteristics of the prediction mode (e.g., directional information, etc.). d.).

[00356] In detail, according to the block size range, a predefined interpolation filter a can be used in some A-bands, a predefined interpolation filter b can be used in some B-bands, an interpolation filter c of a plurality of interpolation filters C can be used in some C-bands, an interpolation filter d of a plurality of interpolation filters D may be used in some D bands, some bands may use a predefined interpolation filter, and some bands may use one of a plurality of interpolation filters. In this case, if the use of one interpolation filter is implicit, the use of one interpolation filter in a plurality of interpolation filters is explicit, and the block size for dividing the range of block sizes may be M×N (in this example, M and N are 4, 8, 16, 32, 64, 128, etc.; that is, M and N can represent the minimum or maximum value of the size range of each block).

[00357] Interpolation-related information may be included in video, sequence, frame, slice, tile, block, etc. elements. The interpolation process may be a process performed in a reference pixel configuration section, or may be a process performed in a prediction block generation section.

[00358] In addition, after configuring the reference pixel, the reference pixel may be filtered to reduce degradation remaining after the encoding/decoding process to improve prediction accuracy. In this case, the filter used may be a low pass filter. The implementation of filtering can be determined according to the encoding/decoding settings, if filtering is applied, fixed or adaptive filtering can be applied, and the encoding/decoding settings can be set according to block size, shape, prediction mode, etc.

[00359] Fixed filtering refers to the case where a predetermined filter is applied to the reference pixel filtering section, and adaptive filtering refers to the case where one of a plurality of filters is applied to the reference pixel filtering section. In this case, in adaptive filtering, one of a plurality of filters may be defined implicitly according to the encoding/decoding settings, or selection information may be generated explicitly and a 3-tap filter may be included as a candidate filter group (e.g. , [1, 2, 1]/4) or a 5-tap filter (for example, [2, 3, 6, 3, 2]).

[00360] As an example, filtering may not be applied in some settings (A block range).

[00361] As an example, filtering may not be applied in some settings (block range B, some mode C), and in some settings (block range B, some mode D) filtering may be applied using a predefined filter (3-tap filter ).

[00362] For example, filtering may not be applied in some settings (E block range, some F mode), in some settings (E block range, in some G mode) filtering may be applied using a pre-filter (3-tap filter), in some settings (range E blocks, some mode H) filtering can be applied using a pre-filter (5-tap filter), and in some settings (range E blocks, some mode I) one of a variety of filters can be used for filtering.

[00363] As an example, in some settings (J block range, some K mode), filtering may be applied by a predefined filter (5-tap filter), and filtering may be further applied by a predefined filter (3-tap filter) . That is, multiple filtering processes can be performed. More details, filtering can also be applied based on the results of previous filtering.

[00364] In the above example, the block size for dividing a range of block sizes may be M×N (in this example, M and N are 4, 8, 16, 32, 64, 128, etc., i.e., M and N may represent the minimum or maximum value of each block size range). In addition, the prediction mode can be roughly classified into directional mode, non-directional mode, color mode, color copy mode, etc., and, in more detail, mode 1 adjacent to horizontal or vertical mode/diagonal mode (45 degree interval)/ horizontal or vertical mode, mode 2 adjacent to the horizontal or vertical mode (the interval between modes is slightly larger than the interval above), etc. That is, as described above, the filtering execution and the filtering type are determined according to the classification mode.

[00365] In addition, the above examples represent a case in which adaptive filtering is applied according to a plurality of factors such as block range and prediction mode. However, multiple factors are not always required, and there may also be an example in which adaptive filtering is performed according to at least one factor. In addition, there may be a variety of transformed examples without limitation to the examples above, and information associated with filtering reference pixels may be included in video, sequence, frame, slice, tile, and block elements.

[00366] Filtering may be selectively performed based on a predetermined flag. The flag may indicate that filtering is performed on the reference pixel to perform intra prediction. The flag may be encoded and reported by the encoder. Alternatively, the flag may be obtained from the decoding device based on the encoding parameter of the current block. The encoding parameter may include at least one of a reference pixel position/area, a block size, a component type, whether intra prediction was applied in the subblock elements, or an intra prediction mode.

[00367] For example, if the reference pixel of the current block is the first line of pixels adjacent to the current block, then the reference pixel may be filtered, otherwise the reference pixel may not be filtered. Alternatively, the reference pixel may be filtered if the number of pixels belonging to the current block is greater than the number of predefined thresholds, otherwise the reference pixel may not be filtered. The threshold value is a value predetermined for the encoding/decoding device and may be an integer of 16, 32, 64 or more. Alternatively, the reference pixel may be filtered if the current block is greater than a predetermined threshold value, otherwise the reference pixel may not be filtered. The threshold value may be represented as M×N, and it is a value predetermined for the encoding/decoding device, and M and N may be integers 8, 16, 32 or more. A threshold number or threshold size may be set to determine filtering of a reference pixel by a single threshold number or threshold size, or a combination thereof. Alternatively, the reference pixel may be filtered if the current block represents a luminance component, otherwise the reference pixel may not be filtered. Alternatively, if the current block does not perform the above-described intra-prediction on the subblock elements (ie, the current block is not split into multiple subblocks), the reference pixel is subject to filtering, otherwise the reference pixel may not be filtered. Alternatively, the reference pixel may be filtered if the intra prediction mode of the current block is an undirected mode or a predetermined directed mode, otherwise the reference pixel may not be filtered. Here, the omnidirectional mode may be a planar mode or a DC mode. However, in DC omnidirectional mode it can be limited to avoid reference pixel filtering. The directional mode may refer to an intra prediction mode with reference to an integer pixel. For example, the directional mode may include at least one of the intra prediction modes corresponding to modes -14, -12, -10, -6, 2, 18, 34, 50, 66, 72, 78 and 80 shown in FIG. 9. However, the directional mode can be limited to eliminate the horizontal mode and vertical mode, which are related to modes 18 and 50, respectively.

[00368] When filtering a reference pixel according to a flag, filtering may be performed based on a filter predefined in the encoding/decoding apparatus. The number of filter taps can be 1, 2, 3, 4, 5 or more. The number of filter taps can be determined to be variable according to the position of the reference pixel. For example, a 1-tap filter may be applied to reference pixels corresponding to at least one side of the bottom-most, top-most, left-most, and right-most ends of a line of pixels, and a 3-tap filter may be applied to the remaining reference pixels. In addition, the filter strength may be determined as variable according to the position of the reference pixel. For example, filter strength s1 may be applied to reference pixels corresponding to at least one side of the lowermost, uppermost, leftmost, and rightmost ends of a line of pixels, and filter strength s2 (s1<s2) may be applied to the remaining reference pixels. The filter strength may be reported to the encoder or may be determined based on the encoding parameters described above. When applying an n-tap filter to a reference pixel, the filter can be applied to the current reference pixel and (n-1) surrounding reference pixels. Surrounding reference pixels may indicate pixels located at at least one of the top end, bottom end, left side, or right side of the current reference pixel. The surrounding reference pixels may belong to the same pixel line as the current reference pixel, and a portion of the surrounding reference pixels may belong to a different pixel line than the current reference pixel.

[00369] For example, if the current reference pixel is located on the left side of the current block, the surrounding reference pixels may be pixels adjacent in at least one direction of the top end or bottom end of the current reference pixel. Alternatively, if the current reference pixel is located at the top end of the current block, the surrounding reference pixels may be pixels adjacent on at least one of the left and right sides of the current reference pixel. Alternatively, if the current reference pixel is located at the top left end of the current block, the surrounding reference pixels may be pixels adjacent at least one of the bottom end or right side of the current reference pixel. The ratio between filter coefficients can be [1:2:1], [1:3:1] or [1:4:1].

[00370] The prediction block generating section is configured to generate a prediction block in accordance with at least one prediction mode and use a reference pixel based on the intra prediction mode. In this case, the reference pixel can be used in methods such as extrapolation (directional mode) in accordance with the prediction mode, and can be used in methods (non-directional mode) such as interpolation or averaging (DC) or copying. At the same time, as described above, the current block may use filtered reference pixels or may use unfiltered reference pixels.

[00371] In FIG. 13 is a diagram showing a block adjacent to a current block for generating a prediction block.

[00372] For example, in the directional mode, the mode between the horizontal mode and some diagonal modes (diagonally top right, including diagonal lines other than horizontal) may use the bottom left block + left block reference pixels (Ref_BL and Ref_L in Fig. 13), in horizontal mode, the reference pixel of the left block can be used, in the mode between horizontal and vertical modes, the reference pixels of left block + top left block + top block (Ref_L, Ref_TL and Ref_T in Fig. 13) can be used, in vertical mode, the reference pixel of the top block (Ref_L in Fig. 13), and in a mode between the vertical mode and some diagonal modes (diagonally bottom left, including diagonals other than vertical), the reference pixels of the top block + top right block (Ref_T and Ref_TR in Fig. 13) can be used. . Alternatively, in omnidirectional mode, the left block and top block reference pixels (Ref_L and Ref_T in Fig. 13) or the bottom left block, left block, top left block, top block and top right block reference pixels (Ref_BL, Ref_L, Ref_TL, Ref_T and Ref_TR in Fig. 13). Alternatively, in the case of color space correlation mode (color copy mode), reconstructed blocks of other color spaces (not shown in FIG. 12, but called Ref_Col in this description; this means that the allocated block reference is in different spaces) are used as reference pixels At the same time).

[00373] The reference pixels used for intra prediction may be divided into a variety of groups. For example, reference pixels used for intra prediction may be allocated to a first reference pixel and a second reference pixel, and the first reference pixel may be a pixel directly used to generate a prediction value of the current block, and the second reference pixel may be a pixel indirectly used to generate the current block's prediction value. Alternatively, the first reference pixel may be a pixel used to generate prediction values of all pixels of the current block, and the second reference pixel may be a pixel used to generate prediction values of some pixels of the current block. Alternatively, the first reference pixel may be a pixel used to generate a main prediction value of the current block, and the second reference pixel may be a pixel used to generate a minor prediction value of the current block. Alternatively, the first reference pixel may (of course) be a pixel in a region at the starting point of the prediction direction of the current block, the second reference pixel may be a pixel not at the starting point of the (desired) prediction direction of the current block.

[00374] As described in the above example, although reference pixels can be distinguished using different definitions, there may be cases in which some definitions are not distinguished according to the prediction mode. That is, it should be noted that the definition used to distinguish reference pixels may differ according to the prediction mode.

[00375] The reference pixel described using the above example may be a first reference pixel, and the second reference pixel may further participate in generating a prediction block. In the mode between some diagonal modes (diagonal top right, including diagonal lines other than horizontal), the reference pixels of the top left block + top block + top right block (Ref_TL, Ref_T and Ref_TR in Fig. 13) can be used, in the horizontal mode can be used reference pixels of the top left block + top block + top right block (Ref_TL, Ref_T and Ref_TR in Fig. 13), in the vertical mode, the reference pixels of the top left block + top block + bottom left block (Ref_TL, Ref_T and Ref_TR in Fig. 13) can be used. 13), in the vertical mode, reference pixels of the top left block + left block + bottom left block (Ref_TL, Ref_L and Ref_BL in Fig. 13) can be used, and in the mode between the vertical mode and some diagonal modes (diagonally from the bottom left, including diagonals, other than vertical) reference pixels of the top left block + left block + bottom left block (Ref_TL, Ref_L and Ref_BL in Fig. 13). In detail, the reference pixel can be used as a second reference pixel. In addition, the first reference pixel or the first and second reference pixels can be used to generate a prediction block in the omnidirectional mode and the color copy mode.

[00376] In addition, the second reference pixel can be considered to include not only the pixels that have been encoded/decoded, but also the pixels in the current block (in this example, the prediction pixels). That is, the main prediction value may be a pixel used to generate the auxiliary prediction value. The present invention will mainly describe an example in which the second reference pixel is considered to be a pixel that has been encoded/decoded, but the present invention is not limited to this, and a converted example in which pixels that have not been encoded/decoded is also used ( in this example - prediction pixels).

[00377] To compensate for the shortcomings of the existing prediction mode, a prediction block may be generated or adjusted using a plurality of reference pixels.

[00378] For example, a directional mode is a mode used to predict the directionality of a corresponding block using some reference pixels (the first reference pixel), however, it may not accurately reflect changes in the block, which may cause a decrease in prediction accuracy. In this case, if the prediction block is generated or adjusted using an additional reference pixel (second reference pixel), the prediction accuracy can be improved.

[00379] To this end, the following example will describe a case in which a prediction block is generated using different reference pixels as in the above example, but the present invention is not limited to the case of the above example, and even if terms such as first and second reference pixels are not used, these terms can be derived and understood from the above definitions.

[00380] The setting to use an additional reference pixel for the purpose of generating a prediction block may be specified explicitly or specified implicitly. Explicitly, an element can contain a video, sequence, frame, slice, tile, etc. The following example will describe the case of implicit processing, however, the present invention is not limited to it, and there may be other, modified (explicit or combined) examples.

[00381] The prediction block may be generated in various ways according to the prediction mode. In detail, the prediction block may be determined according to the position of a reference pixel used in the prediction mode. In addition, the prediction method can be determined according to the position of the pixel in the block.

[00382] The case of the horizontal mode will be described below.

[00383] For example, if the left block (Ref_L in FIG. 13) is used as the reference pixel, a prediction block is generated in the horizontal direction using (eg, extrapolation from) the nearest pixel (1300 in FIG. 13).

[00384] In addition, a prediction block may be generated (or adjusted; the generation may include the final prediction value; the adjustment may not include all pixels) by using reference pixels adjacent to the current block and corresponding to the horizontal direction. In detail, the nearest pixel of the corresponding block (1310 in FIG. 13; other pixels 1320 and 1330 may also be considered) and information about the degree of change, or gradient, of the pixel, etc. can be used to adjust the prediction value. (for example, information about the degree of change, or gradient, of pixel values reflected in R0-T0, T0-TL, T2-TL, T2-T0, T2-T1, etc.) can be fed back to the correction process .

[00385] In this case, the pixels to be corrected may be all pixels in the current block or may be limited to certain pixels (for example, they may be defined in single pixel elements that do not have a specific shape or exist in a variable position, as in the following example, they are defined in line pixel elements having a certain shape; for ease of description, the description in the following example is made on the assumption of a pixel element with a line as an element). If the correction pixel is limitedly applied to some pixels, the element may be defined as at least one line corresponding to the direction of the prediction mode. For example, pixels corresponding to a-d may be included in the correction target, and furthermore, pixels corresponding to e-h may also be included in the correction target. In addition, correction information obtained from adjacent pixels of a block may be applied identically regardless of line position, or correction information may be applied differently across line elements, and as distance from adjacent pixels increases, the applicability of correction information may decrease (for example, according to the distance such as L1-TL and L0-TL, a larger separation value can be set).

[00386] In this case, the pixels included in the correction object may have only one setting in one image or may be determined adaptively in accordance with different encoding/decoding elements.

[00387] As an example, in the case of adaptive determination, pixels to be corrected may be determined according to the block size. In a block less than 8x8, no line is corrected, only one pixel can be corrected in a block greater than 8x8 and less than 32x32, and in a block greater than 32x32 two lines of pixels can be corrected. The definition of the block size range can be obtained from the foregoing description of the present invention.

[00388] Alternatively, the pixels to be corrected may be determined according to the shape of the block (eg, square or rectangular; in particular, a rectangle elongated in the horizontal direction or a rectangle elongated in the vertical direction). For example, in the case of an 8×4 block, two lines of pixels (a-h in FIG. 13) may be subject to correction, and in the case of a 4×8 block, one line of pixels (a-d in FIG. 13) may be subject to correction. If the shape of a horizontally stretched block is determined to be in horizontal mode in case 8x4, the directionality of the current block may be more dependent on the top block, and if the shape of a vertically stretched block is determined to be in horizontal mode in case 4 ×8, the directionality of the current block may depend on the upper block to a lesser extent. In addition, the opposite arrangement to that described above is also possible.

[00389] Alternatively, pixels to be corrected may be determined in accordance with a prediction mode. In horizontal or vertical mode, correction targets can be a pixel lines, while in other modes, correction targets can be b pixel lines. As described above, in the case of some modes (such as DC omnidirectional mode, color copy mode, etc.), the pixels to be corrected are not rectangular, but the range is defined in pixel elements (such as ad, e, i, m) . This will be described in detail in the following example.

[00390] In addition to the above description, adaptive settings may be applied in accordance with additional encoding/decoding elements. The above description focuses on limiting the horizontal mode. However, it does not only apply to the above examples, but similar or similar settings apply to other modes as well. Moreover, the same case as in the above example is implemented according to a combination of multiple elements rather than a single encoding/decoding element.

[00391] In the case of the vertical mode, since it can be obtained by applying different directions to the horizontal mode prediction mode, a detailed description thereof will be omitted. Additionally, the following example omits repeats of content associated with landscape mode.

[00392] The case of the diagonal mode (diagonal up to the right) will be described below.

[00393] For example, if the left block and the lower left block (the first reference pixels, or main reference pixels, Ref_L and Ref_BL in Fig. 13) are used as reference pixels, a prediction block is generated in the diagonal direction using the nearest pixels (1300 and 1340 in Fig. 13) of the corresponding block (for example, by extrapolation, etc.).

[00394] In addition, a prediction block may be generated (or adjusted) using reference pixels (second reference pixels, or auxiliary reference pixels; Ref_T and Ref_TR in FIG. 13) adjacent to the current block located at diagonally opposite positions. In more detail, the prediction value may be adjusted using the nearest pixels of the corresponding block (1310 and 1330 in FIG. 13, and optionally 1320 may be taken into account) and may be fed back into the correction process using a weighted average of the minor reference pixel and the main reference pixel (e.g. , the weighted value may be obtained based on at least one of a prediction pixel, a main reference pixel, or a difference in x-axis or y-axis distances between the prediction pixel and the auxiliary reference pixel; an example of a weighted value applicable to the main reference pixel and the auxiliary reference pixel is may include 15:1 - 8:8; if there are more than two secondary reference pixels, an example of the weighting is that the weighted values in the secondary reference pixels are, for example, 14:1:1, 12:2:2, 10:3:3 , 8:4:4, are the same, or the weightings between the auxiliary reference pixels, such as 12:3:1, 10:4:2, 8:6:2, may differ; in this case, by centering on the corresponding prediction pixel, different weights are determined according to the proximity of the slope information in the current direction of the prediction mode, that is, the gradient of the current prediction mode is determined, which is closer to which the gradient of the corresponding prediction pixel and each auxiliary reference pixel is located).

[00395] In this case, the filtering has one setting in one image, or the filtering is determined adaptively according to different encoding/decoding elements.

[00396] As an example, in the case of adaptive determination, pixels to be filtered (eg, number of pixels, etc.) may be determined according to the positions of pixels to be corrected. If the prediction mode is the diagonal mode (mode 2 in this example) and the pixel to be corrected is c, prediction is performed using L3 (the first reference pixel in this example) and correction is performed using T3 (in this example - second reference pixel). That is, the case may be a case in which one first reference pixel and one second reference pixel are used to predict one pixel.

[00397] Alternatively, if the prediction mode is diagonal mode (mode 3 in this example) and the pixel to be corrected is b, prediction is performed using L1* (or L2*, in this example the first reference pixel) obtained by performing interpolation on the decimal element pixels between L1 and L2, and correction is performed using T2 (the second reference pixel in this example), or correction may be performed using T3. Alternatively, correction may be performed using T2 and T3, or correction may be performed using T2* (or T3*) that are obtained by performing interpolation on the decimal element pixels between T2 and T3 that are obtained based on the directionality of the prediction mode. That is, one first reference pixel can be used to predict one pixel (in this example, assuming L1*, it can be considered as two pixels if the directly used pixels are considered to be L1 and L2; or, according to the filter used to perform interpolation with respect to L1*, it can be considered as two or more pixels) and two second reference pixels (in this example, assuming T2 and T3, L1* can be considered as one pixel).

[00398] Briefly, to predict one pixel, which can be determined in accordance with the prediction mode and the position of the prediction pixel, at least one first reference pixel and at least one second reference pixel can be used.

[00399] If correction pixels are limitedly applied to some pixels, the corrected pixels may be determined in elements of at least one horizontal line or vertical line according to the direction of the intra prediction mode. For example, the correction target may include pixels corresponding to a, e, i and m, or pixels corresponding to a-d, and further, the correction target may also include pixels corresponding to b, f, j and n, or pixels , corresponding to e-h. In some cases of the diagonally up-right mode, pixels in horizontal line elements may be subject to correction, and in some cases of diagonally down-left mode, pixels in vertical line elements may be subject to correction, but are not limited to this.

[00400] In addition to the above description, adaptive settings may be applied in accordance with additional encoding/decoding elements. The above description focuses on limiting the mode diagonally up to the right. However, it does not apply to the above examples only in a restrictive sense, and similar or similar settings apply to other modes as well. In addition, the above example is implemented in accordance with a plurality of elements rather than a combination of one encoding/decoding element.

[00401] In the case of the diagonally down-left mode, since it can only be obtained by applying different directions to the diagonally up-right prediction method, a detailed description thereof will be omitted.

[00402] The case of the diagonally up-left mode will be described below.

[00403] For example, if the left block, the top left block and the top block (the first reference pixels, or main reference pixels, Ref_L, Ref_TL and Ref_T in Fig. 13) are used as reference pixels, a prediction block is generated in the diagonal direction using the nearest pixels (1300, 1310 and 1320 in FIG. 13) of the corresponding block (eg, by extrapolation, etc.).

[00404] In addition, a prediction block may be generated (or adjusted) using reference pixels (second reference pixels, or auxiliary reference pixels, Ref_L, Ref_TL and Ref_T in Fig. 13, in the same position as the main reference pixel) adjacent with the current block, located in positions coinciding with the diagonal lines. In detail, pixels other than the nearest pixels of the corresponding block may be used to correct the prediction value (pixels located on the left side 1300, pixels located on the left side, top side and top left side 1320, pixels located on the top side 1310, and etc. in FIG. 13), and they can be fed back to the correction process by the weighted average of the sub-reference pixel and the main reference pixel (for example, an example of the ratio of the weighted values applied to the main reference pixel and the sub-reference pixel, may include 7:1 - 4:4, etc., if there are more than two sub-reference pixels, an example of the weighted value may be a case in which the weighted values in the sub-reference pixels are the same, for example, 14:1:1, 12:2:2, 10:3:3 and 8:4:4, or the weightings between the auxiliary reference pixels are different, for example, 12:3:1, 10:4:2 and 8:6:2; in this case, weighted values applied differently may be determined according to whether they are adjacent to the main reference pixel) or linear extrapolation, etc.

[00405] If correction pixels are limitedly applied to some pixels, the corrected pixels may be determined in horizontal line elements or vertical line elements adjacent to the reference pixel used in the prediction mode. In this case, horizontal and vertical lines can be counted simultaneously and overlap is allowed. For example, the correction target may include pixels corresponding to a-d and pixels (overlapping with a) corresponding to a, e, i and m. In addition, pixels corresponding to e-h and pixels corresponding to b, f, j and n (a, b, e and f overlap) can be included in the correction target.

[00406] The case of the non-directional mode (DC) will be described below.

[00407] For example, if at least one of the left block, the top block, the top left block, the top right block, or the bottom left block is used as a reference pixel, the prediction block may be used (e.g., averaged, etc.) to generate the prediction block. the nearest pixel of the block (this example assumes pixels 1300 and 1310 in Fig. 13).

[00408] Alternatively, an adjacent pixel of the reference pixel (the second reference pixel, or auxiliary reference pixel, of the reference pixel; the positions of Ref_L and Ref_T in FIG. 13 in this example are the same as the main reference pixel) may be used to generate (or correct) the prediction block , or are complementary to the main reference pixel, the pixel located at the next adjacent position is also included; a case similar to the diagonally up right mode). In detail, pixels at positions the same or similar to the position of the main reference pixel of the corresponding block can be used to correct the prediction value and can be fed back to the correction process using a weighted average of the auxiliary reference pixel and the main reference pixel (for example, an example of the weighted ratio values applicable to the main reference pixel and the secondary reference pixel may include 15:1 - 8:8, etc., if there are more than two secondary reference pixels, an example of the weighted value may be a case in which the weighted values in the secondary reference pixels are the same, for example, 14:1:1, 12:2:2, 10:3:3 and 8:4:4, or the weightings between the sub-reference pixels are different, for example, 12:3:1, 10: 4:2 and 8:6:2).

[00409] In this case, the filtering has one setting for one image, or the filtering is determined adaptively according to different encoding/decoding elements.

[00410] As an example, in the case of adaptive determination, the filter may be determined according to the block size. For pixels located at the top left, at the top end and left end of the current block (in this example, the pixel located at the top left end filters out pixels to the left and above that pixel, and the pixel located at the top end filters out pixels at top side of that pixel, and the pixel at the left end filters out pixels to the left of that pixel), some filtering settings can be used in a block smaller than 16x16 (in this example, filtering is applied according to the 8:4:4 and 12:4 weighting ratios ), and some filtering settings can be used in a block larger than 16x16 (in this example, filtering is applied according to the 10:3:3 and 14:2 weighting ratios).

[00411] Alternatively, the filter may be defined according to the shape of the block. For example, for a 16x8 block, some filter settings may be used for the pixels at the top end of the current block (this example assumes that the pixels on the top left, top and top right sides of the pixel are filtered, so these can be considered an example , in which the filtered pixels are also changed; the filtering weight ratio is 10:2:2:2), and some filter settings can be used for pixels at the left end of the current block (this example assumes that the pixel at the left end of that pixel is being filtered, and the filtration weight ratio is 12:4). This example assumes that it can be applied to multiple pixels on the top side of a block with the block shape elongated in the horizontal direction. In addition, the opposite arrangement can also be realized.

[00412] If the correction is limited to certain pixels, the corrected pixels may be determined in horizontal line elements or vertical line elements adjacent to the reference pixel used in the prediction mode. In this case, horizontal and vertical lines can be counted simultaneously and overlap is allowed. For example, the correction target may include pixels corresponding to a-d and pixels (overlapping with a) corresponding to a, e, i and m. In addition, pixels corresponding to e-h and pixels corresponding to b, f, j and n (a, b, e and f overlap) can be included in the correction target.

[00413] In addition to the above description, adaptive settings may be implemented in accordance with additional encoding/decoding elements. The above description focuses on limiting the omnidirectional mode. However, it does not apply to the above examples only in a restrictive sense, and similar or similar settings apply to other modes as well. Moreover, the same example as described above is implemented in accordance with a combination of multiple elements rather than a single encoding/decoding element.

[00414] The case of the color copy mode will be described below.

[00415] For the color copy mode, the prediction block is generated in a manner different from the prediction method of the existing prediction mode, but the reference pixels can be used in the same way as or similar to generating (or correcting) the prediction block. Since content regarding prediction block acquisition can be obtained using the above examples and the following examples, content regarding prediction block acquisition is omitted.

[00416] For example, a prediction block can be generated by using (eg, copying) as a reference pixel (a first reference pixel, or a main reference pixel) a block corresponding to a current block in another color space.

[00417] Alternatively, a prediction block may be generated (or adjusted) using reference pixels (second reference pixels, or auxiliary reference pixels; Ref_L, Ref_T, Ref_TL, Ref_TR, and Ref_BL in FIG. 13) of a block adjacent to the current block. In detail, the nearest pixels (assumed to be pixels 1300 and 1310 in this example in FIG. 13) of the corresponding block can be used to correct the prediction value and can be fed back into the correction process using a weighted average of the sub reference pixel and the main reference pixel. pixel (for example, an example of the ratio of the weighted values applicable to the main reference pixel and the secondary reference pixel may include 15:1 - 8:8, etc., if there are more than two secondary reference pixels, the example of the weighted value may be the case wherein the weightings within the minor reference pixels are the same, for example, 14:1:1, 12:2:2, 10:3:3 and 8:4:4, or the weightings between the minor reference pixels are different, for example, 12 :3:1, 10:4:2 and 8:6:2).

[00418] Alternatively, pixels of a block adjacent to blocks obtained in other color spaces (second reference pixels, or auxiliary reference pixels; if the frame in FIG. 13 is assumed to be a block corresponding to current block in other color spaces, the pixels are Ref_L, Ref_T, Ref_TL, Ref_TB, Ref_BL and Ref_R, Ref_BR, Ref_B, not shown in Fig. 13). The pixels to be corrected and the surrounding pixels (e.g., the first reference pixel, or the first reference pixel and the second reference pixel in other color spaces, i.e., within a block, if a weighted average or the like is applied, the first reference pixel is required, to be corrected, and the filtered first reference pixel, and a block boundary is required, the first reference pixel to be corrected, and the filtered first reference pixel) may be filtered and fed back to the correction process.

[00419] In case a combination of these two cases occurs, not only pixels of adjacent blocks of the current block can be used, but also pixels in prediction blocks obtained in other color spaces, and pixels to be corrected and surrounding pixels (for example , pixels of adjacent blocks for correction of target pixels and pixels within the current block adjacent to adjacent blocks for correction of target pixels) are filtered (for example, at the correction target position, an M×N mask is used to apply the filtering example; at this point, the mask filters these pixels and all or part of the pixels at the top, bottom, left, right, top left, top right, bottom left, bottom left, etc.) and are fed back into the correction process.

[00420] This example illustrates a case in which filtering is applied after obtaining the prediction value of the current block in other color spaces, but it is also possible to accept the filtered value in the corresponding color space before obtaining the prediction value as the prediction value of the current block. In this example, it should be noted that this case differs from the above example only in the order, and the object being filtered is the same.

[00421] In this case, the filtering has only one setting in one image, or the filtering is determined adaptively according to different encoding/decoding elements.

[00422] For example, in the case of adaptive determination, the filtering setting may be determined in accordance with the prediction mode. In detail, adaptive filtering can be set according to the detailed color copy mode in the color copy mode. For example, in some color copy modes (in this example, if a set of related <a and b> information is obtained in the adjacent region of the current block and the adjacent region of a block corresponding to other color spaces), some <1> filter settings may be accepted, and in some color copy modes (in this example - in comparison with the above mode, if many sets of correlation information are obtained, i.e. a1 and b1, a2 and b2) some <2> filter settings can be adopted.

[00423] The filter settings can determine whether filtering is applied. For example, depending on the filter settings, filter <1> may be applied or filter <2> may not be applied. Alternatively, filter A <1> may be used, or filter B <2> may be used. Alternatively, filtering may be applied to all pixels on the left and top sides of the current block, or filtering may be applied to some pixels on the left and top sides.

[00424] If the pixels to be corrected are limited to certain pixels, the pixels to be corrected may be determined in horizontal line elements or vertical line elements adjacent to reference pixels used in the prediction mode (in this example, different from the previous example, auxiliary reference pixels ). In this case, horizontal and vertical lines can be counted simultaneously and overlap is allowed.

[00425] For example, the correction target may include pixels corresponding to a-d and pixels (overlapping with a) corresponding to a, e, i and m. In addition, pixels corresponding to e-h and pixels corresponding to b, f, j and n (a, b, e and f overlap) can be included in the correction target.

[00426] Briefly, the main reference pixels for generating the prediction block can be obtained from other color spaces, and the auxiliary reference pixels for correcting the prediction block can be obtained from blocks adjacent to the current block of the current color space. Additionally, they can be derived from blocks adjacent to corresponding blocks of other color spaces. In addition, they can be obtained from some pixels of the prediction block of the current block. That is, some pixels in the prediction block may be used to correct some pixels in the prediction block.

[00427] In addition to the above description, adaptive settings may be applied in accordance with additional encoding/decoding elements. The above description focuses on limiting the omnidirectional mode. However, it does not apply to the above examples only in a restrictive sense, and similar or similar settings apply to other modes as well. Moreover, the same example as described above is implemented in accordance with a combination of multiple elements rather than a single encoding/decoding element.

[00428] This example is an example of obtaining a prediction block of the current block using correlation between color spaces, but the block to obtain the correlation is obtained from the adjacent region of the current block and the adjacent region of corresponding blocks in other color spaces, and therefore filtering can be applied to the boundary of the block.

[00429] There are many cases in which a plurality of reference pixels may be used to generate a prediction block in accordance with the encoding/decoding settings. In detail, it can be determined according to the encoding/decoding settings whether generation or correction of a prediction block using the second reference pixel is supported.

[00430] As an example, the use of additional pixels in the prediction process can be specified either implicitly or explicitly. In an explicit case, the above information may be included in video, sequence, frame, slice, tile, block, etc. elements.

[00431] As an example, the determination as to whether to use additional pixels in the prediction process may apply to all prediction modes or may apply to some prediction modes. In this case, some prediction modes may be at least one of horizontal, vertical, some diagonal modes, non-directional modes, color copy modes, or the like.

[00432] As an example, the determination as to whether to use additional pixels in the prediction process may apply to all blocks or may apply to some blocks. In this case, some blocks can be defined according to size, shape, etc. blocks, and the corresponding blocks are M×N blocks (for example, the lengths of M and N are 8, 16, 32, 64, etc.; if the blocks are square, the length is 8x8, 16x16, 32x32, 64x64, etc.; if the blocks are rectangular, the rectangle can have an aspect ratio of 2:1, 4:1, etc.).

[00433] In addition, the use of additional pixels in the prediction process can be determined in accordance with certain encoding/decoding settings. In this case, the encoding/decoding settings may be constrained_intra_pred_flag, and the additional reference pixels may be limitedly used in the prediction process according to the flag.

[00434] For example, if the flag restricts the use of the area containing the second reference pixel (i.e., the area filled by the reference pixel filling process or the like is assumed in accordance with the flag), the use of the second reference pixel in the prediction process may be limited. Alternatively, the second reference pixel may be used in the prediction process regardless of the flag.

[00435] In addition to the cases described by the above example, there may be various applications and modifications, such as combinations of one or more elements. Moreover, although the above example describes only some cases related to the color copying mode, in addition to color copying, this example can be equally or variably used to generate or correct the prediction mode of a prediction block using multiple reference pixels .

[00436] In the above example, a case was described including one setting for generating or correcting a prediction block using a plurality of reference pixels in each prediction mode, but multiple settings may be used for each prediction mode. That is, a plurality of filtering settings candidate groups may be configured to generate selection information.

[00437] Briefly, information about filtering execution may be processed explicitly or implicitly, and when performing filtering, information about filtering selection information may be processed explicitly or implicitly. When processing information explicitly, this information can be included in video, sequence, frame, slice, tile, and block elements.

[00438] The generated prediction block may be corrected, and a process for correcting the prediction block will be described below.

[00439] The correction process may be performed based on predetermined reference pixels and weighting factors. In this case, the reference pixel and the weighted value can be determined according to the position of a pixel (hereinafter referred to as the current pixel) in the current block to be corrected. The reference pixel and the weighted value can be determined in accordance with the intra prediction mode of the current block.

[00440] If the intra prediction mode of the current block is omnidirectional mode, the reference pixels ref_L and ref_T of the current pixel may belong to the first line of pixels adjacent to the current block, and may be located in the same horizontal/vertical line as the current pixel. The weighted value may include at least one of a first weighted value wL in the x-axis direction, a second weighted value wT in the y-axis direction, or a third weighted value wTL in the diagonal direction. The first weighted value may refer to a weighted value applied to a left reference pixel, the second weighted value may refer to a weighted value applied to a top reference pixel, and the third weighted value may refer to a weighted value applied to a top left reference pixel. Here, the first weighted value and the second weighted value may be determined based on the position information of the current pixel and a predetermined scale factor (nScale). The scale factor can be determined based on the width W and height H of the current block. For example, the first weighted value wL[x] of the current pixel predPixel[x][y] is defined as (32>>((x<<1)>>nScale)), and the second weighted value (wT[x]) is defined as ( 32>>((y<<1)>>nScale)). The third weighted value wTL[x][y] can be defined as ((wL[x]>>4) + (wT[y]>>4)). However, if the intra prediction mode is planar mode, the third weighted value can be set to 0. The scale factor can be set to ((Log2(nTbW) + Log2(nTbH)-2)>>2).

[00441] If the intra prediction mode of the current block is vertical/horizontal mode, reference pixels ref L and ref T of the current pixel may belong to the first line of pixels adjacent to the current block and may be located in the same horizontal/vertical line as current pixel. In vertical mode, the first weighted value wL[x] of the current pixel predPixel[x][y] is defined as (32>>((x<<1)>>nScale)), the second weighted value wT[y] can be defined as 0, and the third weighted value wTL[x][y] can be determined to be equal to the first weighted value. On the other hand, in horizontal mode, the first weighted value wL[x] of the current pixel predPixel[x][y] is defined as 0, the second weighted value wT[y] can be defined as (32>>((y<<1) >>nScale)), and the third weighted value wTL[x][y] can be defined to be equal to the second weighted value.

[00442] If the intra prediction mode of the current block is diagonal mode, reference pixels refL and refT of the current pixel may belong to the first line of pixels adjacent to the current block and may be located in the same diagonal line as the current pixel. Here the diagonal line has the same angle as the intra prediction mode of the current block. The diagonal line may represent a diagonal line from the lower left end to the upper right end, or may represent a diagonal line from the upper left end to the lower right end. In this case, the first weighted value wL[x] of the current pixel predPixel[x][y] is defined as (32>>((x<<1)>>nScale)), the second weighted value wT[y] is defined as (32> >((y<<1)>>nScale)), and the third weighted value wTL[x][y] can be defined as 0.

[00443] If the intra prediction mode of the current block is less than or equal to mode 10, the reference pixels refL and refT of the current pixel may belong to the first line of pixels adjacent to the current block, and may be located in the same diagonal line as the current pixel. Here the diagonal line has the same angle as the intra prediction mode of the current block. In this case, the reference pixel may be limited so that only one of the left reference pixel or the top reference pixel of the current block is used. The first weighted value wL[x] of the current pixel predPixel[x][y] is defined as 0, the second weighted value wT[y] is defined as (32>>((y<<1)>>nScale)), and the third weighted the value wTL[x][y] can be defined as equal to 0.

[00444] If the intra prediction mode of the current block is greater than or equal to mode 58, the reference pixels refL and refT of the current pixel may belong to the first line of pixels adjacent to the current block and may be located on the same diagonal line as the current pixel. Here the diagonal line has the same angle as the intra prediction mode of the current block. In this case, the reference pixel may be limited so that only one of the left reference pixel or the top reference pixel of the current block is used. The first weighted value wL[x] of the current pixel predPixel[x][y] is defined as (32>>((x<<1)>>nScale)), the second weighted value wT[y] is defined as 0, and the third weighted the value wTL[x][y] can be defined as equal to 0.

[00445] Based on the determined reference pixels refL[x][y] and refT[x][y] and the weighted values wL[x], wT[y] and wTL[x][y], the current pixel correction predPixels[x ][y] can be done using formula 1 below.

[00446] [Formula 1]

[00447] predPixels[x][y]=clip1Cmp((refL[x][y]*wL[x]+refT[x][y]*wT[y]-p[-1][-1]* wTL[x][y]+(64-wL[x]-wT[y]+wTL[x][y])*predPixels[x][y]+32)>>6)

[00448] However, the above-described correction process can only be performed when the current block does not perform intra prediction on the subblock elements. The correction process can only be performed when the reference pixel of the current block is the first line of pixels. The correction process can only be performed when the intra prediction mode of the current block matches a specific mode. Here, the particular mode may include at least one of a non-directional mode, a vertical mode, a horizontal mode, a mode that is less than a predetermined first threshold mode, or a mode that is greater than a predetermined second threshold mode. The first threshold mode may be 8, 9, 10, 11 or 12, and the second threshold mode may be 56, 57, 58, 59 or 60.

[00449] The prediction mode determination section performs an optimal mode selection process in a plurality of candidate prediction mode groups. To determine the mode with the optimal encoding cost, in order to generate the number of bits of the corresponding mode, the block distortion (e.g., distortion of the current block and the reconstructed block; sum of absolute difference (SAD), sum of squared difference (SSD), etc.) can be generally considered. and random distortion technology. The prediction block generated based on the prediction mode determined by the above process may be sent to the subtraction section and the addition section.

[00450] The prediction mode encoding section is configured to encode the prediction mode selected by the prediction mode determining section. In a group of candidate prediction modes, index information corresponding to a prediction mode may be encoded, or a prediction mode may be predicted to encode information associated therewith. That is, the first case indicates a method of directly encoding a prediction mode without performing prediction, and the last case indicates a method of predicting a prediction mode such that prediction information of the encoding mode and information obtained based on the prediction information are encoded. Moreover, the first example is an example that can be applied to a chroma component, and the last example is an example that can be applied to a luminance component. The present invention is not limited to these examples, and other cases are also possible.

[00451] In the case of performing prediction encoding of a prediction mode, the prediction value (or prediction information) of the prediction mode may be called a most probable mode (MPM). In this case, a preset prediction mode (e.g., DC mode, planar mode, vertical mode, horizontal mode, diagonal mode, etc.) or a spatially adjacent block prediction mode (e.g., left block, top block, top left) is configured as MPM block, top right block, bottom left block, etc.). In this example, the diagonal mode may represent a diagonally up-right, diagonally down-right, and diagonally down-left mode, which may correspond to mode 9, mode 2, and mode 66 in FIG. 9.

[00452] In addition, a mode obtained from modes included in a candidate MPM group may be configured as a candidate MPM group. For example, in the case of a directional mode included in a group of candidate MRMs, a mode with a difference a of the intervals between modes (for example, a is a non-zero integer such as 1, -1, 2 or -2; in case in Fig. 9 there was added mode 10, derived modes are mode 9, mode 11, mode 8, mode 12, etc.) is re-included (or additionally included) in the group of MRM candidates.

[00453] The above example may correspond to the case in which the MPM candidate group is executed in a plurality of modes, the MPM candidate group (or the number of MPM candidate groups) may be determined according to the encoding/decoding settings (for example, the candidate mode group prediction, image type, block size, block shape, etc.), and at least one mode may be enabled.

[00454] The prediction mode for configuring a group of MPM candidates may have priority. The order of prediction modes included in the MPM candidate group can be determined according to priority, and the configuration of the MPM candidate group can be completed if the number of MPM candidate groups is filled according to the priority. In this case, the priority may in turn be a spatially adjacent block prediction mode, a predetermined prediction mode, and a mode derived from the prediction mode originally included in the MPM candidate group, but other modifications are possible.

[00455] If prediction mode encoding of the current block is performed using MPM, information about whether the prediction mode matches the MPM (eg, most_probable_mode_flag) may be generated.

[00456] If the prediction mode matches the MPM, (eg, most_probable_mode_flag=1), MPM index information (eg, mpm_idx) may be additionally generated according to the MPM configuration. For example, if the MPM is executed as a single prediction mode, no additional MPM index information is generated, and if the MPM is executed as a plurality of prediction modes, index information corresponding to the prediction mode of the current block may be generated in a group of candidate MPMs.

[00457] If the prediction mode is not the same as the MPM (e.g., most_probable_mode_flag=0), in the remaining candidate prediction mode group (or non-MPM candidate mode group) different from the MPM candidate group in the candidate prediction mode groups, non-MPM mode index information (eg, non_mpm_idx) corresponding to the current mode prediction mode may be generated, which may be an example of a case in which the non-MPM mode is configured as one group.

[00458] If the non-MPM candidate mode group consists of multiple groups, information about which group the prediction mode of the current block belongs to can be generated. For example, a non-MPM mode is configured by groups A and B (assuming that A is configured with m prediction modes, B is configured with n prediction modes, the non-MPM mode is configured with m+n prediction modes, and n is greater than m; assuming that the mode from group A is a directional mode and has equal intervals, and the mode from group B is a directional mode and is not equal intervals), if the prediction mode of the current block is the same as the prediction mode from group A (for example, non_mpm_A_flag= 1), index information corresponding to the prediction mode of the current block can be generated in candidate group A, and if there is no match (for example, non_mpm_A_flag=0), index information corresponding to the prediction mode of the current block can be generated in the remaining mode groups - prediction candidates (or group B candidates). As in the above example, the non-MPM mode may be configured as at least one candidate prediction mode group (or set), and the configuration of the non-MPM modes may be determined in accordance with the candidate prediction mode group . For example, if there are no more than 35 candidate prediction mode groups, there may be one non-MPM mode, and in other cases there are two or more non-MPM modes.

[00459] As in the above example, the purpose of supporting non-MPM modes is that the number of prediction modes is large if the non-MPM mode consists of many groups, and the number of mode bits is reduced if the prediction mode not predicted by MPM.

[00460] If prediction mode encoding (or prediction mode decoding) of the current block is performed using MPM, the binarization table applied to each prediction mode candidate group (e.g., MPM candidate mode group, non-candidate mode group MPM, etc.) can be generated separately, and the binarization method applied to each candidate group can also be applied separately.

[00461] Prediction-related information that is generated by the prediction mode encoding section may be transmitted to the encoding section and included in the bit stream.

[00462] In FIG. 14 shows an example of a tree division block according to an embodiment of the present invention.

[00463] In FIG. 14 i represents a quaternary tree-based partition, ii represents a horizontal partition when a binary tree-based partition is used, and iii represents a vertical partition when a binary tree-based partition is used. In this figure, A-C represent the original blocks (the blocks before the split, for example, assuming it represents a coding tree element), and the numbers after the text represent the number of each section after the split is made. In the case of a quaternary tree, the top left block, top right block, bottom left block and bottom right block are respectively assigned numbers 0-3, and in the case of a binary tree, the left/top block and bottom/right block are respectively assigned numbers 0 and 1 .

[00464] With reference to FIG. 14, the division state or information about the division performed to obtain the corresponding block can be determined by text and numbers obtained in the division process.

[00465] For example, in image i of FIG. 14, block A00 is the top left block (adding 0 to A0) in the four blocks obtained by performing a quaternary tree split on the top left block A0 (adding 0 to A) of the four blocks obtained after performing a quaternary tree split. in relation to the original block A.

[00466] Alternatively, in image ii of FIG. 14, block B10 is the top block (adding 0 to B1) in two blocks obtained by performing a horizontal split in a binary tree-based partition on the bottom block B1 (adding 1 to B) of the two blocks obtained after performing a horizontal split in a split. based on a binary tree regarding the source block B.

[00467] Using the above-described partitioning, the partition status and partition information (eg, supported partition settings <tree mode type, etc.>) of each block, block support range such as minimum size and maximum size <details - support range according to the division method>, allowable division depth <detail - support range according to the division method>, division flag <detail - division flag according to the division method>, image type <I/P/B>, division status block encoding mode <intra prediction/prediction carried out between pictures>, encoding/decoding settings required to confirm information, information, etc., and it can be confirmed which block (generating block) the current block belongs to before the separation step with the purpose of obtaining the current block (generated block). For example, in image i of FIG. 14, for block A31, adjacent blocks may include A30, A12 and A13, and it may be confirmed that A30 belongs to the same block A3 as A31 in the division step of the previous step. In the case of A12 and A13 in the previous stage, that is, in the splitting stage, A3, A12 and A13 belong to another block A1, and it can be confirmed that A12 and A13 belong to the same block A only in the previous stage.

[00468] While the previous example is for the case of a single splitting operation (quaternary splitting of a quaternary tree or horizontal/vertical splitting of a binary tree), the following examples will explain the case of performing splitting based on multiple trees.

[00469] In FIG. 15 illustrates an example of a multi-tree partitioning block according to an embodiment of the present invention.

[00470] With reference to FIG. 15, the division status or information about the division performed to obtain the corresponding block can be confirmed through text and numbers obtained in the division process. In this example, each word does not indicate the original block, but the division information is indicated by a number.

[00471] For example, in the case of block A1A1B0, the upper right block A1 is obtained by performing a quaternary tree split on the original block, the upper right block (adding A1 to A1) is obtained by performing a quaternary tree split on block A1, and the top block (adding B0 to A1A1) is represented when performing a horizontal binary tree split on block A1A1.

[00472] Optionally, in the case of block A3B1C1, the lower right block A3 is obtained by performing a quaternary tree split on the original block, the bottom block (adding B1 to A3) is obtained by performing a horizontal split when performing a binary tree split on block A3 , and the right block (adding C1 to A3B1) is represented when performing vertical partitioning in the binary tree partitioning process on A3B1.

[00473] In this example, using the division information according to the division step of each block, it is possible to determine information about the relationship between the current block and the adjacent block, for example, at what division stage the current block and the adjacent block are identical.

[00474] In FIG. 14 and 15 show some examples of determining the division information of each block, and the division information of each block can be confirmed using various information to determine the division information and combined information (for example, division flag, depth information, maximum value of depth information, range block, etc.) so that the relationship between blocks can be determined.

[00475] In FIG. 16 is a schematic diagram showing various situations of block division.

[00476] In general, since there is various texture information in an image, it is difficult to perform encoding/decoding using the encoding/decoding method. For example, some regions may contain regions in which stronger edge components exist in a certain direction, and some regions may contain complex regions in which edge components do not exist. To efficiently perform coding on these areas, block division plays an important role.

[00477] The purpose of performing block division is to efficiently divide regions according to image features. However, when using only one division mode (eg, quaternary tree division), it may be difficult to properly reflect the image characteristics to perform division.

[00478] With reference to FIG. 16, it can be confirmed that images containing different textures are divided according to the quaternary tree-based division and the binary tree-based division. a-e may represent a case in which only a quaternary tree-based partition is supported, and f-j may represent a case in which only a binary-tree-based partition is supported.

[00479] In this example, the partitions according to the quaternary tree-based partition are called UL, UR, DL and DR, and the binary tree-based partition is also described on this basis.

[00480] Image a of FIG. 16 may be a texture form in which the quaternary tree division achieves optimal efficiency: it can be divided into four parts by one quaternary tree division (Div_HV), and encoding/decoding is performed in the elements of each block. At the same time, when applying binary tree-based partitioning as shown in image f of FIG. 16, unlike a quaternary tree, three divisions may be required (Div_V twice, Div_H once).

[00481] Image b of FIG. 16 is such that the texture is divided into the upper and lower block regions, in image b of FIG. 16, if a quaternary tree-based partition is applied, one partition (Div_HV) is required, and in image g of FIG. 16, one Div_H split can also be performed in binary tree based splitting. Assuming that the quaternary tree split flag requires 1 bit and the binary tree split flag requires more than 2 bits, the quaternary tree can be considered efficient in terms of flag bits, but encoding/decoding information (e.g., information for expressing texture information (information for expressing texture (residual signal, coding coefficient, information indicating the presence or absence of a coding coefficient)), prediction information <for example, information related to intra prediction and information related to prediction performed between pictures> ,transformation information <such as transformation category information, transformation division information, etc.>) is generated in the elements of each block. In this case, the efficiency of quaternary tree-based partitioning is low compared to binary tree-based partitioning, since texture information is an example of dividing similar regions and generating the corresponding information anew.

[00482] In other cases, FIG. 16 It is also possible to determine which wood is more efficient according to the texture category. From the above examples, it can be confirmed that, in order to be able to divide the effective area according to the characteristics of the image using the above examples, supporting variable block size and various division modes is extremely important.

[00483] A detailed analysis of the quaternary tree-based partition and the binary tree-based partition is performed as follows.

[00484] With reference to image b in FIG. 16 shows blocks (in this example, the left block and the top block) adjacent to the bottom right block (the current block). It can be seen that the left block is a block having characteristics similar to the current block, and the top block is a block having characteristics different from the current block. Although the block has properties similar to some blocks (in this example, the left block), there is a possible case in which the block was segmented based on the properties of partitioning based on a quaternary tree.

[00485] In this case, since the current block has similar characteristics to the left block, similar encoding/decoding information can be generated. In the case of intra prediction mode (for example, MPM, i.e., information predicting the mode of the current block based on adjacent blocks in order to reduce the number of bits of the prediction mode of the current block), a motion information prediction mode appears (for example, skip mode, merge mode , information to shorten the mode bits (eg, contention mode)) to effectively eliminate this situation, while the left block information is available for sending. That is, if the encoding information (eg, intra prediction information, inter-picture prediction information, filter information, coefficient information, etc.) of the current block is assigned to one of the left block and the top block, it may be a reference is made to more precise information (in this example, to the left block).

[00486] With reference to image e in FIG. 16, a small block is assumed in the lower right corner (a block dividing the current block twice). Likewise, the current block also has characteristics similar to the top block of the left block or the top block, so the encoding efficiency can be improved by referring to the encoding information from the corresponding block (in this example, the top block).

[00487] Conversely, with reference to image j in FIG. 16, a reference is made to the left block adjacent to the rightmost block (the block that divides the current block twice). In this example, since there is no top block, by referring only to the left block, it can be verified that the current block is a block having a different characteristic than the left block. It can be confirmed that the quaternary tree-based partition can be similar to a portion of contiguous blocks, while the binary tree-based partition has a high probability of obtaining different characteristics from contiguous blocks.

[00488] In detail, if some blocks (x) and adjacent blocks (y) are the same blocks before the corresponding partition, for quaternary tree partitioning, some blocks (x) and adjacent blocks (y) which are the same, as blocks before splitting may have similar characteristics or different characteristics, and conversely, for a binary tree in most cases, some blocks (x) and adjacent blocks (y) that are the same as blocks before splitting may have different characteristics. In other words, if there is a case of similar characteristics, there is no need to perform block splitting, and the blocks are finalized before splitting, but in most cases, blocks are split due to different characteristics.

[00489] In addition to the above example, in image i of FIG. 16, the lower right block x and the lower left block y can have the following relationships. That is, since the image characteristics of the upper blocks are similar, the division is determined without performing division, and since the image characteristics of the lower blocks are different, the division is determined after dividing into the lower left block and the lower right block.

[00490] Briefly, in the case of a quaternary tree partition, if there is a contiguous block having a parent block identical to the current block in contiguous blocks adjacent to the current block, it may have characteristics similar to or different from the current block because the characteristic of the quaternary tree is the unconditional division of the block into 1/2 in the horizontal and vertical directions. In the case of binary tree-based partitioning, if there is a contiguous block having a parent block identical to the current block in contiguous blocks adjacent to the current block, the adjacent block can be split horizontally or vertically according to the characteristics of the image, so it has been subjected to separation" can mean separation due to different characteristics.

[00491] (Quadary tree partitioning)

[00492] An adjacent block (in this example, assumed to be, but not limited to, a left block or a top block) that is the same as the block before the division, compared to the current block, may have characteristics similar to or different from the current block.

[00493] In addition, contiguous blocks other than the current block and the block before the division may have characteristics similar to or different from the current block.

[00494] (Binary tree partitioning)

[00495] An adjacent block (in this example, assumed to be a left block or a top block, the maximum number of candidates is one due to the binary tree) that is the same as the block before the split may have different characteristics compared to the current block.

[00496] In addition, contiguous blocks other than the block before the division, compared to the current block, may have characteristics similar to or different from the current block.

[00497] Descriptions will be made below with the understanding that the above assumption is the basic assumption of the present invention. According to the contents above, it is possible to distinguish between case (1) in which the characteristics of adjacent blocks are similar to or different from the current block, and case (2) in which the characteristics of adjacent blocks are different from those of the current block.

[00498] Reference is made again to FIG. 15.

[00499] As an example (the current block is A1A2), since the block A1 before the division of block A1A2 is different from the block before the division (original block) of block A0, the block A0 (the left block) in adjacent blocks can be classified (i.e. in the case where it is unknown whether the characteristic is similar or different from the current block) as a general case.

[00500] For the adjacent block A1A0 (upper block), since the block A1 before block A1A2 is divided is the same as the block before block A1A0 is divided, the division mode can be confirmed. In this case, since the partitioning mode is partitioning (A) based on a quaternary tree, it is classified as the general case.

[00501] As an example (the current block is A2B0B1), the block A2B0 before the block A2B0B1 is divided is the same as the block A2B0B1 before the block A2B0B1 is divided for the block A2B0B0B0 (upper block) in adjacent blocks, thus confirming the division mode. In this case, since the partitioning mode is binary tree-based partitioning (B), it is classified as an exceptional case.

[00502] As an example (the current block is A3B1C0), in adjacent blocks, since block A3B1 before block A3B1C0 is divided is different from block A3 before block A3B0 is divided, block A3B0 (in this example, the upper right block) can be classified as common happening.

[00503] As described in the above example, contiguous blocks can be classified into a general case and an exceptional case. For the general case, it is unknown whether the encoding information of the corresponding adjacent block can be used as the encoding information of the current block, and for an exception, it is determined that the encoding information of the corresponding adjacent block cannot be used as the encoding information of the current block.

[00504] Based on the above classification, a method for obtaining prediction information of the current block from adjacent blocks can be used.

[00505] Briefly, it is confirmed whether the blocks before dividing the current block and adjacent blocks are the same (A).

[00506] If A has the same result, the split mode of the current block (if this is the case, then not only the current block but also adjacent blocks are blocks defined using the same split mode, thus confirming only the current block) is confirmed (B).

[00507] If the result of A is different, the process terminates (ends).

[00508] If the result of B is a quaternary tree partition, adjacent blocks are marked as normal and the process terminates (ends).

[00509] If the result of B is a binary tree partition, adjacent blocks are marked as exclusive and the process terminates (ends).

[00510] The above example can be applied to setting up an intra prediction mode prediction group (associated with MPM) according to the present invention. The general prediction candidate group settings (eg, candidate group configuration priorities, etc.) and the exclusive prediction candidate group settings may be supported, and the priorities may be shifted back or excluded from the candidate groups obtained from a block based on the states of the above adjacent blocks.

[00511] In this case, the contiguous blocks in which these settings are applied may be limited to the spatial case (one space) or may be applicable to the case of obtaining from other color spaces a single image, such as a color copy mode. That is, the above settings may be made taking into account the prediction state or the like. for a block obtained using the color copy mode.

[00512] In addition to the above example, the following example is an example of adaptively determining encoding/decoding settings (eg, prediction candidate group settings, reference pixel settings, etc.) according to the relationship between blocks (in the above example, relative the relationship between the current block and other blocks is identified using split block information, etc.).

[00513] This example (luminance component) is described based on the assumption that a total of 3 candidates (in this example, left and right) are selected from adjacent blocks, and they are specified as a group of MPM candidates if the encoding/decoding apparatus There are 35 predefined intra prediction modes.

[00514] By adding one candidate to the left block L0 and the top block T0, respectively, a total of two candidates can be configured. If a candidate group cannot be configured in each block, it can be replaced or filled with DC mode, planar mode, vertical mode, horizontal mode, diagonal mode, etc. If two candidates are filled using the above process, the remaining candidate may be considered as the filled number in various cases.

[00515] For example, if the candidates populated in each block are the same, adjacent modes of the above-described mode are replaced in a manner that does not overlap with the modes included in the candidate group (e.g., k_mode-2, k_mode-2, k_mode+1, k_mode+ 2, etc. if the same mode is k_mode). Alternatively, if the candidates filled in each block are the same or different, the candidate group may be configured by adding a planar mode, a DC mode, a vertical mode, a horizontal mode, and a diagonal mode.

[00516] Using the above process, a group (general case) of candidate intra prediction modes can be configured. The candidate group thus established belongs to the general case, and an adaptive intra prediction mode candidate group (exceptional case) can be configured according to adjacent blocks.

[00517] For example, if a contiguous block is marked with an exceptional condition, a candidate group derived from that block may be excluded. If the left block is marked as an exceptional state, the candidate group can be configured by a top block and a predefined prediction mode (eg, a mode derived from a DC block, a planar block, a vertical block, a horizontal block, a diagonal block, and a top block, etc. .). The above example can be applied identically/similarly even when the MPM candidate group is configured with more than three MPM candidates.

[00518] The description will be made based on the following assumptions: this example (chroma component) contains five intra prediction modes (DC mode, planar mode, vertical mode, horizontal mode and, in this example, color mode), and encoding/decoding is performed by configuring prediction modes that are adaptively prioritized as groups of candidates (ie, encoding/decoding is performed directly, without the use of MRM).

[00519] First, the color mode is given the highest priority (in this example, index 0; "for 0" is assigned 1 bit), while the other modes (in this example, planar, vertical, horizontal, and DC) are given low priority ( in this example, respectively, with indices 1-4, 3 bits are assigned with the values “100”, “101”, “110”, “111”).

[00520] If a color mode matches one of the other prediction modes (DC, planar, vertical, and horizontal) from a group of candidates, the priority assigned to the matching prediction mode (indices 1-4 in this example) may be assigned to the predefined prediction mode (eg diagonal mode, etc.), and if there is no match, the candidate group configuration is completed.

[00521] Using the above process, a group of candidates for the intra prediction mode can be configured. An example implemented in this manner corresponds to the general case, and an adaptive candidate group can be configured according to the blocks of the obtained color mode.

[00522] In this example, if a block corresponding to the current block in other color spaces of the received color mode is configured as a single block (i.e., a non-split state), it may be called a general case, and if it is configured as a plurality of blocks ( i.e. the state of separation of more than two blocks), it can be called an exceptional case. As described above, there may be an example based on the following assumptions: this example is different from the example in which classification is performed according to whether the current block is the same as the parent block of an adjacent block, with a split mode or the like, and If many corresponding blocks of different color spaces are configured, there is a higher probability of characteristics different from the current block. That is, this should be understood as an example of adaptively determining encoding/decoding settings in accordance with the relationship between blocks.

[00523] If a corresponding block is marked as an exception according to the assumption example above, the prediction mode derived from that block may have a low priority. In this case, one of the other prediction modes (planar, DC, vertical and horizontal) may be given high priority, and low priority may be given to other prediction modes and color modes not included in the priority.

[00524] For ease of description, the above examples are described based on some assumptions, but without limitation, and the same or similar applications may be used for the various embodiments of the present invention described above.

[00525] To summarize, candidate group A can be used when there are blocks marked as exceptional conditions in adjacent blocks, and candidate group B can be used when there are blocks marked as exceptional conditions. It should be understood that the above classification is divided into two cases, but the configuration of a group of intra prediction candidates in block elements can be adaptively implemented in accordance with the exceptional states and positions of blocks.

[00526] In addition, the above example describes tree partitioning in partition mode, but is not limited to it. In detail, in the above example, it is possible to set a block obtained using at least one tree division mode as an encoding block and directly perform prediction, transformation, etc. without dividing this block into prediction blocks, transformation blocks, etc.

[00527] As another example of partition settings, a coding block is obtained using a tree partition, and based on the obtained coding block, at least one prediction block is obtained.

[00528] For example, it is assumed that a (2N×2N) encoding block can be obtained using a tree partition (in this example, based on a quaternary tree), and a prediction block is obtained using a typed partition (the candidate types supported in this example are are 2N×2N, 2N×N, N×2N and N×N). In this case, if an encoding block (in this example, assumed to be a parent block) is divided into a plurality of prediction blocks (in this example, assumed to be sub-blocks), setting the above-described exception state or the like. can also be used between prediction blocks.

[00529] As shown in image g of FIG. 16, if there are two prediction blocks (separated by a thin solid line) in an encoding block (thick solid line), the lower block has a different characteristic from the upper block and does not belong to the encoding information of the upper block or has a low priority.

[00530] In FIG. 17 illustrates an example of block division according to an embodiment of the present invention. In detail, an example is shown in which a basic encoding block (maximum encoding block, 8N×8N) obtains a coding block (diagonal block, 2N×2N) using a quaternary tree-based partition, and the resulting encoding block is divided into at least one prediction block (2N×2N, 2N×N, N×2N and N×N) using typed partitioning.

[00531] The setting of a group of candidate intra prediction modes for the case of obtaining rectangular blocks (2N×N and N×2N) will be described below.

[00532] In FIG. 18 illustrates various examples of candidate intra prediction mode groups with respect to the setting of blocks generating prediction information (the prediction blocks in this example are 2N×N blocks).

[00533] This example assumes that if there are 67 intra prediction modes (luminance component), a total of 6 candidates are selected from adjacent blocks (in this example, left, top, top left, top right, and bottom left) and are set to group of MRM candidates.

[00534] With reference to FIG. 13, four candidates can be configured in the order L3-T3-B0-R0-TL, and two candidates can be configured in a preset mode (eg, planar and DC). In the above configuration, if the maximum number (in this example - 6) is not filled, the prediction mode can be enabled (for example, k_mode-2, k_mode-2, k_mode+1, k_mode+2, etc., if k_mode is available), obtained from the prediction modes included in the candidate group, a predefined mode (eg vertical, horizontal or diagonal, etc.), etc.

[00535] In this example, in the case of spatially contiguous blocks, the priority of the candidate group is the order left block-top block-bottom left block-top right block-top left block of the current block (more details, subblocks on the bottom side of the left block and the right side of the top block), and for the predefined mode, in turn, the order planar-DC-vertical-horizontal-diagonal mode is assumed.

[00536] With reference to image a of FIG. 18, as with configuring the candidate group in the above example, the current block (2N×N, PU0) can configure the candidate group in the order l1-t3-l2-tr-t1 (since other contents are repeated, they are omitted). In this example, an adjacent block of the current block may represent a block that has been encoded/decoded (an encoding block, ie a prediction block in other encoding blocks).

[00537] In contrast to the above, if the position of the current block corresponds to PU1, at least one candidate intra prediction mode group may be specified. In general, a block adjacent to the current block is more likely to have similar characteristics to the current block, and is therefore more advantageous for configuring the group of candidates from the corresponding block (1). On the other hand, it may be necessary to configure a group of candidates for parallel encoding/decoding processing (2).

[00538] If the current block is PU1, when setting up a candidate group building as in case (1), for example, image b of FIG. 18, candidate groups can be configured in the order l3-c7-bl-k-l1 (k can be obtained from c7 or tr, etc.), and in the case of setting the candidate group configuration as in case (2), for example ,in image c of Fig. 18, candidate groups can be configured in the order l3-bl-k-l1 (k can be obtained from tr, etc.). The difference between these two examples is whether the candidate intra prediction mode group for the top block is enabled. That is, in the first case, the upper block intra prediction mode is included in the candidate group to improve the encoding/decoding efficiency of the intra prediction mode, and in the latter case, the upper block intra prediction mode that cannot be referenced is excluded from the candidate group for parallel processing or the like. etc., since it has not yet been determined whether encoding/decoding is complete.

[00539] In FIG. 19 shows various examples of settings of candidate intra prediction mode groups with respect to the settings of blocks generating prediction information (the prediction blocks in this example are N×2N blocks).

[00540] This example assumes that if there are 67 intra prediction modes (luminance component), a total of 6 candidates are selected from adjacent blocks (in this example, left, top, top left, top right, and bottom left) and are set to group of MRM candidates.

[00541] Referring to FIG. 13, one candidate can be configured in the order L3-L2-L1-L0 (upper block), one candidate can be configured in the order T3-T2-T1-T0 (upper block), two candidates can be configured in the order B0-R0-TL (top left block, top right block and bottom left block), and the two candidates can be configured in a predefined mode (eg planar or DC). In the above configuration, if the maximum number is not filled, a prediction mode obtained from prediction modes included in the candidate group, a preset mode, etc. may be included. In this case, the priority of the candidate group configuration may be the order left block-upper block-planar block-DC block-lower left block-upper right block-upper left block.

[00542] With reference to image a of FIG. 19, the current block (N×2N, PU0) can configure one candidate in the order l3-l2-l1-l0, one candidate in the order t1-t0 and two candidates in the order bl-t2-tl in the same way as group settings candidates in the examples above. In this example, an adjacent block of the current block may represent a block that has been encoded/decoded (encoding block; ie, a prediction block in other encoding blocks).

[00543] In contrast to the above, if the position of the current block corresponds to PU1, at least one candidate intra prediction mode group may be specified. In the above examples, (1) and (2) can be configured.

[00544] If the current block is PU1, one candidate in the order c13-c9-c5-c1, one candidate in the order t3-t2, and two candidates in the order k-tr-t1 can also be configured (k can be obtained from bl or c13, etc.) when setting up the candidate group configuration as in (1), for example, in image b of Fig. 19, and also one candidate can be configured in the order t3-t2 and two candidate groups in the order k-tr-t1 (k can be obtained from bl, etc.) when setting the candidate group configuration as in (2) , for example, in image c of FIG. 19. The difference between these two examples is whether the candidate intra prediction mode group for the top block is enabled. That is, in the first case, the left block intra prediction mode is included in the candidate group to improve the encoding/decoding efficiency of the intra prediction mode, and in the latter case, the left block intra prediction mode that cannot be referenced is excluded from the candidate group for parallel processing or the like. etc., since it has not yet been determined whether encoding/decoding is complete.

[00545] Thus, the candidate group configuration can be determined in accordance with the candidate group configuration settings. In this example, candidate group configuration settings (in this example, candidate group configuration settings for parallel processing) may be defined implicitly, or related information may be explicitly included in video, sequence, frame, slice, tile, etc. elements .

[00546] A brief description of the above contents is as follows. The associated information is assumed to be defined implicitly or generated explicitly.

[00547] The configuration setting of the candidate intra prediction mode group is confirmed at the initial encoding/decoding stage (A).

[00548] If the acknowledgment result for A is such that a reference can be made to the setting of the previous prediction block in the same encoding block, the intra prediction mode of the block is included in the candidate group (end).

[00549] If the confirmation result for A is such that reference to the setting of a previous prediction block in the same encoding block is prohibited, the intra prediction mode of the block is excluded from the candidate group (end).

[00550] For ease of description, the above examples are described on the basis of certain assumptions, but without limitation, and the same or similar applications may be applied to the various embodiments of the present invention described above.

[00551] In FIG. 20 illustrates an example of block division according to an embodiment of the present invention. In detail, a basic coding block (maximum coding block) represents an example of obtaining a coding block (diagonal A×B block) by dividing based on a binary tree (or divisions based on multiple trees), and the resulting coding block is specified as a prediction block.

[00552] In this case, the setting of the motion information prediction candidate group for the case of obtaining a rectangular block (A×B, A≠B) will be described below.

[00553] In FIG. 21 illustrates various examples of candidate intra prediction mode groups for tuning blocks generating prediction information (in this example, a 2N×N encoding block).

[00554] The description is made based on the following assumptions. If a given example (luminance component) contains 67 intra-prediction modes, a total of 6 candidates are selected from adjacent blocks (in this example, left, top, top-left, top-right, and bottom-left) and assigned to the MPM candidate group. If multiple non-MPM candidate mode groups are configured (in this example, A and B, the mode in which the current block prediction mode has a higher probability of being predicted in non-MPM candidate modes belongs to A), group A has a total of There are 16 candidates and a total of 45 candidates are configured in Group B.

[00555] In this case, group A contains candidates classified according to certain rules (for example, composed of equidistant modes in a directional mode) that are not included in the modes from the MPM candidate groups, or may contain candidates that are not included in the final MPM group -candidates according to the priority of the MPM candidate group, etc. Group B may be composed of candidates not included in group A, the MPM candidate group and the non-MPM candidate mode group.

[00556] With reference to image a of FIG. 21, the current block (CU0 or PU0, in which the size is assumed to be 2N×N and the horizontal/vertical size ratio is 2:1) can configure six candidates as a candidate group in the order l1-t3-planar-DC-l2-tr- tl-l1*-t3*-l2*-tr*-tl*-vertical-horizontal-diagonal mode. In the example above, "*" represents the mode derived from the prediction mode of each block (for example, the mode with +1, -1, etc. added).

[00557] On the other hand, with reference to image b of FIG. 21, the current block (CU1 or PU1 in which the size is 2N×N) can configure six candidates as a group of candidates in the order l3-c7-planar-DC-bl-k-l1-l3*-c7*-bl*-k *-l1*-vertical-horizontal-diagonal mode.

[00558] In this example, in the case where the setting (2) shown in FIG. 18, as shown in image b of FIG. 21, the candidate group is excluded from the upper block prediction mode candidate group according to the order l3-planar-DC-bl-k-l1-c7-l3*-bl*-k*-l1*-vertical-horizontal-diagonal-c7 *, or the priority is reduced, and thus it can be included in group A.

[00559] However, unlike the case shown in FIG. 18 is as follows: even if the block is rectangular, the block is divided into encoding elements and immediately set as a prediction block without further division. Therefore, as shown in FIG. 18, the candidate group configuration setting may not be applicable to this example (eg, setting (2)).

[00560] However, in case k in FIG. 21, since there is a position in which encoding/decoding is not completed, it can be obtained from an adjacent block in which encoding/decoding is completed.

[00561] In FIG. 22 shows various examples of setting candidate intra prediction mode groups for blocks generating prediction information (coding blocks in this example are N×2N blocks).

[00562] The description will be made based on the following assumptions. If a given example (chroma component) contains five intra prediction modes (in this example, DC mode, planar mode, vertical mode, horizontal mode, and color copy mode), encoding/decoding is performed by configuring the prediction modes that are adaptively prioritized as groups candidates.

[00563] In this case, the priority will be described based on the assumption that the priority is determined from contiguous blocks (in this example, left, top, top left, top right and bottom left).

[00564] With reference to FIG. 13, a first-class candidate may be defined in the left block L3, the upper block T3, the upper left block TL, the upper right block R0 and the lower left block B0. In this case, the mode having the value most frequently found in block prediction modes can be defined as the first class candidate. If the most frequently occurring values have multiple modes, the preset priority is given (for example, copy mode color-planar-vertical-horizontal-DC).

[00565] This example can be considered similar to setting up MPM candidates (in this example, the first bit is defined as 0 or 1; if the first bit is 1, 2 bits need to be added; the first bit can perform bypass encoding or traditional encoding according to the encoding settings /decoding, and the remaining bits can perform bypass encoding) with respect to obtaining the mode (the mode is the mode evaluated as the prediction mode of the current block) from adjacent blocks and thus determining the priority (that is, determining the number of bits assigned; for example, in the case of the first class it is equal to "0"; in the case of classes from the second to the fourth they are equal to "100", "101", "110" and "111") and in relation to the prediction of the prediction mode.

[00566] With reference to image a of FIG. 22, the current block (CU0 or PU0, in which the size is assumed to be N×2N and the horizontal/vertical size ratio is 1:2) can determine first-class candidates in blocks l3, t1, t1, t2 and b1.

[00567] On the other hand, with reference to image b of FIG. 22, the current block (CU1 or PU1 in which the size is N×2N) can determine the first class candidate in blocks c13, t3, t1, tr and k.

[00568] In this example, if the same setting as (2) shown in FIG. 19, the current block CU1 can determine the first class candidate in blocks t3, t1, tr and k. In addition, if the block corresponding to the current block in other color spaces in which the color copy mode is obtained is not configured as one block, the priority of the color copy mode is shifted back (lowered) in the preset priority so that the priority changes to planar-vertical- horizontal-DC-color copy mode, etc. As described above, this example may take place based on the following assumptions. This example is different from the example in which classification is performed according to whether the current block is the same as the parent block of an adjacent block, with a split mode or the like, however, if a plurality of corresponding blocks of different color spaces are configured, there are more high probability of characteristics different from the current block. That is, this should be understood as an example of adaptively determining encoding/decoding settings in accordance with the relationship between blocks.

[00569] However, unlike the case shown in FIG. 19 is as follows: even if the block is rectangular, the block is divided into encoding elements and corresponds to the case of immediate setting as a prediction block without further division. Therefore, as shown in FIG. 19, the candidate group configuration setting may not be applicable in this example.

[00570] However, in case k in FIG. 22, since there is a position in which encoding/decoding is not completed, it can be obtained from an adjacent block in which encoding/decoding is completed.

[00571] For ease of description, the above examples have been described on the basis of some assumptions, but without limitation, and the same or similar applications are possible in the various embodiments of the present invention described above.

[00572] In the embodiments shown in FIGS. 21 and 22, it is assumed that M×N (M≠N) blocks that can be divided by binary tree partitioning appear sequentially.

[00573] In the above case, the case described in FIG. 14-16 (an example of setting up a candidate group by determining the relationship between the current block and an adjacent block, etc.). That is, in FIG. 21 and 21 contiguous blocks before division of CU0 and CU1 are identical to each other, and CU0 and CU1 can be obtained by horizontal division or vertical division by binary tree-based division.

[00574] Additionally, in the embodiments shown in FIGS. 18 and 19, it is assumed that after the coding block is divided, there are a plurality of rectangular prediction blocks in the coding block.

[00575] In the above case, the case described in FIG. 14-16. Then there is a contradiction with the examples presented in Fig. 18 and 19. For example, in FIG. 18, in the case of PU1, it can be determined whether to use the information of PU0, and in FIG. 14-16, PU0 information is not used because the characteristics of PU1 are different from those of PU0.

[00576] Regarding the above contents, the candidate group can be configured without conflict according to the setting of the original encoding/decoding stage. The motion information prediction candidate group may be set in accordance with various other encoding/decoding settings.

[00577] The case of setting a group of candidate prediction modes is described in the above example. In addition, it can be specified to restrict the use of reference pixels for the purpose of predicting the current block from adjacent blocks marked with exceptional conditions.

[00578] For example, if a prediction block is generated by distinguishing a first reference pixel from a second reference pixel according to an embodiment of the present invention, in case the second reference pixel is included in a block marked as an exception, generating a prediction block using the second reference pixel may be limited. That is, the prediction block can be generated using only the first reference pixel.

[00579] Briefly, the above example can be considered as an element in the encoding/decoding settings relating to the use of the second reference pixel.

[00580] Various cases will be described herein with respect to the settings of a candidate intra prediction mode group.

[00581] In this example, it is assumed that there are 67 intra prediction modes configured as 65 directional modes and 2 non-directional modes, namely planar mode and DC mode. However, it is not limited to them, and other intra prediction modes can be specified. This example assumes that there are six candidates included in the MRM candidate pool. However, it is not limited to this, and the MPM candidate group can also be configured with four, five or seven candidates. In addition, there is a setting in which there is no overlapping mode in the candidate group. In addition, priority relates to the order in which MRM candidates are included in the group, but can be considered as an element for determining binarization, entropy encoding/decoding settings, etc. for each candidate belonging to the group of MRM candidates. The following example will be described by focusing on the luminance component, however the same or similar or modified applications can also be made for the chroma component.

[00582] The modes included in the intra prediction candidate mode group (eg, the MPM candidate group, etc.) according to the present invention can be configured as spatially contiguous block prediction modes, predefined prediction modes, prediction modes derived from modes predictions included in candidates, etc. In this case, a rule (eg priority, etc.) can be defined to configure a group of candidates according to the encoding/decoding settings.

[00583] The following examples describe cases related to fixed candidate group configurations.

[00584] As an example (1), a fixed priority may be maintained for configuring an intra prediction mode candidate group (in this example, an MPM candidate group). For example, a predefined priority may be supported. For example, if prediction modes of spatially adjacent blocks are added to a candidate group, the preset priority is the order left block (L3 in FIG. 13)-top block (T3 in FIG. 13)-bottom-left block (B0 in FIG. 13)- top right block (R0 in Fig. 13) - top left block (TL in Fig. 13). If a preset prediction mode is added to a candidate group, the preset priority is the order planar-DC-vertical-horizontal-diagonal mode. Additionally, a combination configuration of the above example may occur, such as the order left block-upper block-planar block-DC block-lower left block-upper right block-upper left block. If the number of candidates cannot be reached even when the candidates are executed according to priority, the next priority may have a mode derived from the prediction mode that was turned on (for example, +1 and -1 left block modes, +1 and -1 top block modes etc.), vertical mode, horizontal mode, diagonal mode, etc.

[00585] In the above example, if spatially adjacent block prediction modes are added to a candidate group, the candidate modes have the priorities left block-upper block-lower left block-upper right block-upper left block, and the left block prediction modes (L3 in FIG. 12) are sequentially included in the candidate group, at the same time, if the corresponding modules do not exist, the upper block prediction mode (T3 in Fig. 13) is included in the candidate group as the next priority. Thus, the prediction mode is included in the candidate group in some order, and if the prediction mode of the corresponding block is not available or overlaps with the included mode, the order moves to the next block.

[00586] As another example, if spatially adjacent block prediction modes are added to a candidate group, the candidate group may be configured in the order left block-upper block-lower left block-upper right block-upper left block. In this case, the left block prediction mode first considers the prediction mode of the block located in L3, but if there is an unavailable or overlapping mode there, the candidate left block prediction modes are filled in the order of the next subblocks of the left block L2, L1 and L0. Likewise, the same or similar settings apply to the top block (T3-T2-T1-T0), bottom left block (B0-B1-B2-B3), top right block (R0-R1-R2-R3) and top left block (TL). For example, if block prediction modes cannot be added to the candidate group even if executed in the order L3-L2-L1-L0, the next sequential block may be executed.

[00587] The following examples describe cases of adaptive candidate group configurations. The adaptive configuration of the candidate group may be determined according to the state of the current block (eg, block size and shape), the state of the adjacent block (eg, block size and shape, prediction mode, etc.), or the relationship between the current block and the adjacent block.

[00588] As an example (3), an adaptive priority for configuring a group of candidate intra prediction modes (in this example, a group of MPM candidates) may be supported. The priority can be set according to the frequency. That is, prediction modes that occur more frequently may have high priority, while prediction modes that occur less frequently may have low priority.

[00589] For example, the priority may be set according to the frequency of prediction modes of spatially adjacent blocks.

[00590] A preset priority for the case of the same frequency can be supported. For example, assuming that the modes appearing twice in the left block, top block, bottom left block, top right block, and top left block, respectively (assuming that one prediction mode is obtained for each block) are mode 6 and mode 31, and the mode a appearing once is mode 14, in this example (assuming that the mode a appearing in the previous sequential block in the order left block-upper block-lower left block-upper right block-upper left block is mode 6 ) mode 6 and mode 31 are included as the first candidate and second candidate.

[00591] Planar mode and DC mode are included as the third and fourth candidates, and mode 14 having a frequency 1 prediction mode is included as the fifth candidate. Then mode 5 and mode 7, derived from the first candidate and second candidate, and modes 30 and 32 can be given the following priority. In addition, mode 13 and mode 15 derived from the fifth candidate are given the next priority, and then the vertical mode, horizontal mode and diagonal mode may have the next priority.

[00592] That is, a prediction mode having a frequency of 2 or more is given priority before the planar mode and the DC mode, and a prediction mode having a frequency of 1 may be given priority after the planar mode and the DC mode, for example, the derivative mode has low priority, preset mode, etc. of the above example.

[00593] Briefly, a predetermined priority (e.g., the order left block-top block-planar block-DC-block-bottom left block-top right block-top left block) may be a priority set taking into account the statistical characteristics of the image as a whole , and the adaptive priority (in this example, the case in which it is included in a group of candidates according to frequency) may be an example of performing a partial modification of the predefined priority, taking into account some characteristic features of the image (in this example, the mode that appears with a frequency of two or more is set before the fixed planar mode and DC mode, and the mode appearing with frequency one is set after the fixed planar mode and DC mode).

[00594] In addition, not only the priority with respect to the configuration of the candidate group can be determined according to the frequency, but the binarization and entropy encoding/decoding settings for each candidate belonging to the MPM candidate group can also be determined based on the frequency. . As an example, the binarization of MRM candidates having m frequencies can be determined based on frequency. Alternatively, contextual information about the candidates can be adaptively determined according to the frequency. That is, in this example, contextual information can be used that sets the probability of choosing a mode as high. That is, when m is 1-4 (in this example, the omnidirectional mode is included in 2 of the total 6 candidates, and thus the maximum frequency value is 4), the context information can be specified in different ways.

[00595] If 0 to 0 and 1 of binary index (Bin index; bit order when more than one bit is configured according to binary conversion; for example, if some MPM candidate is configured as "010", numbers from the first binary number to third binary number can be 0, 1 and 0) is a binary number indicating that the candidate is selected as an MPM (the binary number is used to determine whether the MPM is final, or whether an additional binary number must be confirmed to recognize the final MPM; that is, in the above "010", if the first binary number is 0, the second binary number and the third binary number need to be confirmed, and whether the mode is MRM finite can be confirmed; if there is one binary number, it is immediately confirmed whether the MRM is finite, according to with the values 0 and 1 of a binary number), and 1 represents a binary number indicating that the candidate is not selected as an MRM, contextual information with a high probability of occurrence of 0 is applied (that is, when performing binary arithmetic, the probability of occurrence of 0 can be equated to 90%, the probability of occurrence of 1 can be set to 10%, and the base case is assumed to be such that the probabilities of occurrence of 0 and 1 are 60% and 40%), so that CABAC can be applied.

[00596] As an example (4), an adaptive priority for configuring a group of candidate intra prediction modes (in this example, a group of MPM candidates) may be supported. For example, the priority may be set according to the directionality of the prediction modes of spatially adjacent blocks.

[00597] In this case, the directional categories are: the mode group in the direction of the upper right corner (2-17 in Fig. 9), the horizontal mode group (18 in Fig. 9), the group of modes in the direction of the lower right corner (19-49 in FIG. 9), a vertical mode group (50 in FIG. 9), a lower left corner direction mode group (51-66 in FIG. 9), and an omnidirectional mode group (planar mode or DC mode). Alternatively, they can be divided into a group of horizontally directed modes (modes 2-34 in Fig. 9), a group of vertically directed modes (modes 35-66 in Fig. 9) and a group of non-directional modes (planar mode or DC mode), and also possible various configuration examples.

[00598] For example, if the priority of the base candidate group is the order upper left block-planar DC block-lower left block-upper right block-upper left block, then the candidate group may be configured in the above order. However, once candidate groups are configured, priorities for binarization and entropy encoding/decoding settings for each candidate can be determined based on category. As an example, binarization with fewer bits assigned may be performed for categories in a candidate MPM group containing a large number of candidates. Alternatively, contextual information may be adaptively determined according to the category. That is, the context information may be determined according to the number of modes included in each category (eg, if the first category is m and the second category is n, the context information is determined according to the combination of m and n).

[00599] As an example (5), adaptive priority may be maintained according to the size and shape of the current block. For example, the priority may be determined according to the block size, and the priority may be determined according to the block shape.

[00600] If the block size is 32×32 or more, it may be included in the candidate group in the order left block-upper block-planar block-DC block-lower left block-upper right block-upper left block, and if the block size is less than 32x32, it can be included in the candidate group in the order left block-upper block-lower left block-upper right block-upper left block-planar block-DC block.

[00601] Alternatively, if the block is square, it may be included in the candidate group in the order left block-upper block-planar block-DC block-lower left block-upper right block-upper left block if the block is rectangular (elongated by horizontal), it can be included in a candidate group in the order top block-top right block-top left block-planar block-DC block-left block-bottom left block, and if the block is rectangular (vertically elongated), it can be included in the candidate group in the order left block-lower left block-upper left block-planar block-DC block-upper right block. This example can be understood as a case in which blocks adjacent to longer blocks are of higher order.

[00602] As an example (6), adaptive priority may be maintained in accordance with the relationship between the current block and adjacent blocks.

[00603] Referring to image a in FIG. 23 shows an example of generating a prediction block in accordance with the prediction mode of an adjacent block (in this example, a sub-block of the left block).

[00604] If the prediction mode (used, for ease of description, only with reference to the directed content) of the left block (in this example, the upper sub-block of the left block) is a directed mode existing among modes 51-66 in FIG. 9 (right slant mode in vertical mode), and if a left block prediction block is generated, then the reference corresponds to the diagonal portion (TL or T portion) in the figure. The right region of the left block may essentially be a region having a high correlation with the left region of the left block, however, since encoding/decoding has not yet been completed, a prediction block may be generated using reference pixels of the lower region T where encoding/decoding has been completed .

[00605] Even if prediction is performed from a portion of the lower region of block T as described above, the final prediction mode is defined as a mode existing among modes 51-66, and this means that some regions 2400 of the current block also have the same or similar directionality (or edges, etc.) like the above prediction mode.

[00606] That is, it may mean that the probability of selecting the prediction mode of the left block as the prediction mode of the current block is high. Alternatively, this could mean that modes 51-66 are more likely to be selected.

[00607] Referring to image b in FIG. 23, when the corresponding description is derived from the above example when the upper block prediction modes exist in modes 2 to 17 in FIG. 9 (downward slant mode in horizontal mode), this may mean that some areas of the current block also have the same directionality as the corresponding prediction modes.

[00608] That is, this may mean that the probability of selecting the prediction mode of the upper block as the prediction mode of the current block is higher. Alternatively, it could mean that modes 2-17 are more likely to be selected.

[00609] As described above, if it is possible to determine the prediction mode of the current block by the prediction modes of adjacent blocks, the priority can be determined adaptively.

[00610] For example, if the candidate base group is configured with a priority order of left block-upper block-planar block DC-lower left block-upper right block-upper left block, the priority does not change in the case identical to a in FIG. 23, and may change in the order of upper block-left block-planar block-DC block-lower left block-upper right block-upper left block in case b in FIG. 23.

[00611] Alternatively, for case a in FIG. 23, the order left block-(left+1) block-(left-1) block-up block-planar block-DC block-lower left block-upper right block-lower left block may occur, and for case b in FIG. 23 it can change in the order of top block-(top-1) block-(top+1) block-left block-planar block-DC block-bottom left block-top right-bottom left block.

[00612] Referring to image a in FIG. 24 shows an example of generating a prediction block in accordance with the prediction mode of an adjacent block (in this example, a left block).

[00613] In the case where the prediction mode of the left block is a mode having a directionality existing among modes 51 to 66 in FIG. 9, its related pixels for generating a left block prediction block correspond to the diagonal portions TL and T in the figure. The right region of the left block may be a region having a high correlation with the left region of the left block, however, since encoding/decoding has not yet been completed, a prediction block may be generated using reference pixels of the lower region of the T block where encoding/decoding has been completed.

[00614] Even if prediction is performed from the lower region of block T as described above, the final prediction mode is defined as the mode existing among modes 51-66, and this means that some regions of the current block also have the same or similar directionality (or edges, etc.) like the above prediction mode.

[00615] That is, it may mean that the probability of selecting the left block prediction mode is high. Alternatively, it could mean that the likelihood of selecting modes 51-66 is high.

[00616] Referring to image b in FIG. 24, when the corresponding description is derived from the above example when the upper block prediction modes exist in modes 2 to 17 in FIG. 9, this may mean that some regions of the current block also have the same directionality as the corresponding prediction modes.

[00617] That is, it may mean that the probability of selecting the prediction mode of the upper block as the prediction mode of the current block is high. Alternatively, it could mean that the probability of selecting modes 2-17 is high.

[00618] As described above, if it is possible to determine the prediction mode of the current block by the prediction modes of adjacent blocks, the priority can be determined adaptively.

[00619] For example, if the candidate base group is configured with a priority order of left block-upper block-planar block DC-lower left block-upper right block-upper left block, the priority does not change for case a in FIG. 24 and may change in the order of top block-left block-planar block-DC block-bottom left block-top right block-top left block for case b in FIG. 23. In this case, as in case a in FIG. 24, the priority is the same as before, but instead, the binarization and entropy encoding/decoding settings for left block prediction candidate modes in the MPM candidate group can be adaptively determined. As an example, a binarization (assigning shorter bits) of the candidate prediction modes for the left block may be specified. Alternatively, contextual information may be adaptively determined. That is, in this example, contextual information can be used that sets the probability of selecting a candidate as high.

[00620] If the 0 in the 0 and 1 of some binary index is a binary number indicating that the candidate is selected as the MPM (in the case of determining whether it is the final MPM using a single binary number or confirming an additional binary number for the purpose of recognizing the final MPM ), and 1 represents a binary number indicating that the candidate is not selected as an MPM, CABAC can be applied by applying contextual information that the probability of occurrence of 0 is high.

[00621] Alternatively, for case a in FIG. 24 the order can be left block-(left+1) block-(left-1) block-(left+2) block-(left-2) block-top block-planar block-block DC-bottom left block-top the right block is the lower left block, and for case b in Fig. 24 it can change in the order top block-(top-1) block-(top+1) block-(top-2) block-(top+2) block-left block-planar block-DC block-bottom left block- top right-bottom left block.

[00622] Referring to image a in FIG. 25 shows an example of generating a prediction block in accordance with the prediction mode of an adjacent block (in this example, a left block).

[00623] A case is considered in which the left block and lower left block prediction modes have a directionality existing among modes 51 to 66 in FIG. 9. The left block and the bottom left block may or may not belong to the same block. In this example, for ease of description, it is assumed that the left block and the lower left block belong to the same block (ie, the same mode) for which the division has been completed.

[00624] The pixels referred to in generating the prediction block of the (left+lower-left) blocks correspond to the diagonal portions TL, T and TR in the figure. Even if prediction is performed from the bottom region of block T and block TR as described in the above example, the final prediction mode is defined as the mode existing among modes 51 to 66, and this means that the entire region of the current block also has the same or similar directionality , like the above prediction mode.

[00625] That is, it may mean that the probability of selecting the prediction mode of the left block or the lower left block (in this example, the prediction modes of these two blocks are the same) as the prediction mode of the current block is (very) high. Alternatively, it could mean that the probability of selecting modes 51-66 is high (in this example, the prediction modes of the two blocks are different).

[00626] In image b of FIG. 25, if the (top + top right) block prediction modes exist among modes 2 to 17 in FIG. 9, this may mean that the entire area of the current block also has the same directionality as the corresponding prediction modes.

[00627] That is, it may mean that the probability of selecting the prediction mode of the top block or the top right block (in this example, the prediction modes of these two blocks are the same) as the prediction mode of the current block is (very) high. Alternatively, it could mean that the probability of selecting modes 2-17 is high (in this example, the prediction modes of the two blocks are different).

[00628] As described above, if it is possible to determine the prediction mode of the current block by the prediction modes of adjacent blocks, the priority can be determined adaptively.

[00629] For example, if the candidate base group is configured with a priority order of left block-upper block-planar block DC-lower left block-upper right block-upper left block, it may change in the order left block-lower left block- planar DC block-top block-top right block-top left block for case a in Fig. 25. The priority may change in the order top block-upper right block-planar block-DC block-left block-lower left block-upper left block for case b in FIG. 25. That is, the priority of the associated block can be pushed forward.

[00630] Alternatively, for case a in FIG. 25 priority can be changed in the order left block-bottom left block-(left+1) block-(left-1) block-(bottom left+1) block-(bottom left-1) block-planar block-DC block-top block-top right block-top left block, and for case b in Fig. 25 priority can be changed in the order top block-top right block-(top-1) block-(top+1) block-(top right-1) block-(top right+1) block-planar block-DC block-bottom left block is the top left block.

[00631] Moreover, in the case of FIG. 25, based on the category described in the fourth example, the binarization and entropy encoding/decoding setting of each candidate belonging to the MPM candidate group can be determined. As an example, binarization (ie, assignment of shorter bits) for MPM candidates (modes a and b of FIG. 24) may be specified. Alternatively, contextual information may be adaptively determined according to the category. That is, in this example, contextual information can be used to set the high probability of occurrence of the category to which this mode belongs (modes a and b in Fig. 25).

[00632] If 0 in 0 and 1 of some binary index is a binary number indicating that a mode belonging to a category other than the above-described category is selected as MPM, and 1 is a binary number indicating that a mode belonging to to a specified category, CABAC can be applied by applying contextual information indicating a high probability of occurrence of 1.

[00633] To confirm the above-described contents, it is necessary to confirm whether a block located in a predetermined direction (left, top, top left, top right and bottom left) is configured as a single (ie, non-divided) block. Therefore, if a block is configured as a single block, then the prediction mode case of that block is executed, and if it is configured as a split block, then some or all of the prediction modes of each block are confirmed to execute that case. However, the complexity of this case may be significantly increased.

[00634] To this end, the process can be configured simply. The range of the current block is assumed to be (a, b) - (a+M-1, b+N-1). The left block contains pixels centered on the current block and belonging to the range (a-1, b) - (a-1, b+N-1). The directionality of the left block's prediction mode can be determined by confirming the prediction modes of some, but not all, pixels.

[00635] For example, the directionality of the prediction block is determined using the coordinate prediction mode of the upper right (based on the current block - upper left) side of the left block (a-1, b) and the coordinate prediction mode of the lower right (based on the current block - lower left) sides of the left block (a-1, b+N-1). In this case, the left block can be configured as a single block and can be configured as a split block. Even if it is a single block or a split block, the prediction modes including coordinates may be the same. However, even if the prediction modes are not the same, if they are prediction modes belonging to modes 51 to 66 in FIG. 9, as described by image a in FIG. 24, prediction mode, coding of these prediction modes may be given high priority.

[00636] The above example assumes the left block case, but other directions apply similarly. In addition to the left block, to confirm the prediction mode of the lower left block, it is possible to confirm the prediction mode belonging to the coordinates of the lower left block, for example, (a-1, b+N).

[00637] Briefly, this can be used to refer to the configuration of a group of candidate intra prediction modes by confirming the prediction modes with respect to some coordinates of a block located in a predetermined direction, and confirming the prediction modes or the directionality of the prediction modes in that direction. In this case, the number of coordinates may be an integer equal to 1 or more, such as 1, 2 and 3.

[00638] To summarize, if a mode that is determined to have a high correlation with the current block is confirmed, that mode may be given high priority in the candidate group. Alternatively, high priority within the candidate group may be given to prediction modes derived from a given mode (eg, adjacent prediction modes such as +1 or -1). That is, a given mode may prioritize all or part of a prediction mode or predefined prediction modes (DC mode, planar mode, horizontal mode, vertical mode, diagonal mode, etc.) of other spatially adjacent blocks.

[00639] Unlike the case described in the above example, if it cannot be determined whether there is a high correlation with the current block, a base-level candidate group can be configured. That is, given a method for configuring a candidate group of a high-correlation process, one of a plurality of methods for configuring a group of prediction mode candidates or configured candidate groups can be selected based on state information (size, shape, block position, prediction mode, etc.). ) adjacent blocks.

[00640] In FIG. 26 is a schematic diagram of the relationship between the current block and the adjacent block.

[00641] In image a of FIG. 26 shows the encoding order according to the division block.

[00642] When performing partitioning based on a quaternary tree, encoding is performed in the order of upper left block (0)-upper right block (1)-lower left block (2)-lower right block (3). If quaternary tree-based partitioning (depth 1) is further performed in sub-blocks, encoding is performed in the above order in each sub-block (depth 2), and encoding is performed before the depth information. For a top left block divided at depth 1, the order is top left block (0-0)-top right block (0-1)-bottom left block (0-2)-bottom right block (0-3) at depth 2 For a bottom right block divided at depth 1, the order is top left block (3-0), top right block (3-1), bottom left block (3-2), and bottom right block (3-3) at depth 2. That is, encoding is performed in x-y-z order represented by depth information.

[00643] When performing partitioning based on a binary tree, encoding is performed in the order left block (0)-right block (1), or top block (0)-bottom block (1) in the case of horizontal partitioning. If binary tree-based partitioning (depth 1) is further performed in sub-blocks, encoding is performed in the above order in each sub-block (depth 2), and encoding is performed before the depth information.

[00644] In image a of FIG. 26, in the case where the block 3 is the same as in image a in FIG. 25, and the block 16 is the same as in image a in FIG. 23, block 20 corresponds to the same case as in image a in FIG. 24.

[00645] For example, block 3 is a case in which the left block is configured as one block without division from the lower left block and has a prediction mode (one mode) in a specific direction or has prediction modes (more than one mode) in a specific direction, even if the left block is separated from the bottom left block.

[00646] Block 16 is a case in which the left block is configured as a plurality of blocks after division, and at least a portion of the sub-blocks have a prediction mode (one mode) in a particular direction.

[00647] Block 20 represents a case in which the left block is configured as one block and has a prediction mode (one mode) in a particular direction, or the left block is configured as a plurality of sub-blocks after division, and all sub-blocks have prediction modes (more than one mode) in a specific direction.

[00648] An example of the relationship between the current block and the adjacent block is depicted by image b in FIG. 26. If this relationship is defined as in image b of FIG. 26, it can be taken into account when configuring a group of candidate prediction modes.

[00649] Using the above examples, some examples of the relationship between the current block and the adjacent block are tested, but various other cases are possible, and the configuration of the candidate intra prediction mode group can be set based on the specific case.

[00650] In addition, in the above examples, various cases are tested with respect to the configuration of a group of candidate intra prediction modes. A candidate group may be configured to apply one of the settings described in each embodiment, wherein the settings described in each embodiment may be applied in the same or similar manner in other embodiments, and a plurality of settings may be applied to configure the candidate group. Additionally, a candidate group configuration can be created by combining the above examples with additional settings.

[00651] In this example, assuming an example in which the non-MPM candidate mode group is configured as a plurality of candidate groups (group A and group B), the prediction mode of the MPM candidate group is not selected, and encoding/decoding is performed with using a candidate mode group (group A), in which the next one of the prediction modes of the non-MPM candidate mode group is evaluated as the prediction mode of the current block.

[00652] In this example, it is assumed that 16 candidates are included in candidate group A and 45 candidates are included in candidate group B.

[00653] When configuring the candidate group A configuration, various methods may be used, and a prediction mode not included according to the priority of the MPM candidate group may be included in the candidate group A.

[00654] Alternatively, candidate group A may be configured according to a predefined category regardless of the above example. For example, in FIG. 9, the candidate group can be configured with prediction modes at certain intervals. That is, group A can include blocks 2, 6, 10, 14, 18, etc. in fig. 8. In this case, for group B, blocks 3, 4, 5, 7, 8, 9, 11, etc. can be included in group B. Of course, modes included in the group of MRM candidates are excluded from this setting.

[00655] The present invention is not limited to the above examples, and various modifications and other customizations are also possible.

[00656] Briefly, the MPM candidate group is configured first, and then the candidate group A is configured. In addition, the remaining prediction modes can be configured as candidate group B.

[00657] A mode in the MPM candidate group may use truncated unary to binary, a mode from candidate group A may use a fixed-length binary conversion, and a mode from candidate group B may use a truncated unary to binary conversion , although various other binary conversion methods may be used.

[00658] A mode from the MPM candidate group can perform encoding/decoding on all or part of the binary numbers using the conventional encoding section, and a mode that is a non-MPM candidate mode can perform encoding/decoding on all the binary numbers using the bypass coding section. Alternatively, a mode from candidate group A in the non-MPM candidate mode group may perform encoding/decoding on a portion of the binary numbers using the conventional encoding section, but is not limited to this and various cases may be used.

[00659] The above has been a description of the basic settings, and many converted embodiments may occur in the present description.

[00660] Below, a case in which a prediction block is generated using a plurality of reference pixels will be described.

[00661] In FIG. 27 shows an example of generating a prediction block using multiple layers of reference pixels.

[00662] As the prediction value of x pixels of the current block, a pixel value generated by applying a weighted average to a of ref_1 and b of ref_2 can be used.

[00663] Generating a prediction block using multiple layers of reference pixels sometimes results in better prediction results. That is, this means that when generating prediction values for the pixels of the current block, multiple pixels can lead to more accurate prediction results.

[00664] However, re1_1 and ref_2 may be applied in the case where the current block has a high correlation with the edge direction or the like, and in some cases, using multiple reference pixel layers may lead to worse prediction results. For example, if the current block has high correlation in the vertical direction, and if the upper block has high correlation in the diagonal direction, using multiple reference pixel layers may not achieve a good effect.

[00665] In this case, it is preferable to explicitly define whether an existing reference pixel layer should be used or multiple reference pixel layers should be used.

[00666] Alternatively, using multiple reference pixel layers to generate a prediction block by confirming whether there is a high correlation between the reference pixel layers can be determined implicitly.

[00667] In the above example, it is shown that in intra prediction, division is performed on the elements of predefined subblocks, and prediction and transformation are performed based on the subblocks, etc. In this case, subblocks belonging to the current block can share the intra prediction mode. In this case, by applying multiple layers of reference pixels to sub-blocks in a block, better results can be achieved.

[00668] In FIG. 28 shows an example of generating sub-blocks in the current block using multiple layers of reference pixels. The current block is a 4M×4N block, the sub-block is 4M×N, and forward prediction is performed (top->down or left->right as a reference point, reverse prediction is bottom->up, right->down), whereas the prediction mode using reference pixels whose prediction directions are the top left block, the top block and the top right block is k (No. 66 in FIG. 9).

[00669] With reference to FIG. 28, a 4M×N subblock containing x can perform intra prediction using the first previous subblock that has been encoded as the reference pixel layer. Alternatively, the subblock containing x may perform intra prediction using the second previous subblock that was encoded as the reference pixel layer. Alternatively, the subblock containing x may perform intra prediction using the first and second previous subblocks as reference pixel layers (if a weight is applied to each reference pixel layer, the weight applied to the subblock containing x is greater than or equal to the weighting of the others subblocks).

[00670] In general, the unconditional use of reference pixel layers does not always lead to the correct result if multiple reference pixel layers are used based on a coding block. However, in the above example, the previous subblock of the target subblock used for encoding has the same direction as the target subblock, thus leading to a better result. Therefore, to explicitly determine the execution or selection of one of the reference pixel layers, a plurality of reference pixel layer settings can be explicitly applied to subblocks in the current block. Alternatively, multiple reference pixel layers may be implicitly applied to the first k subblocks of the target subblock to generate a target subblock prediction value.

[00671] If multiple sub-blocks are respectively set to use different reference pixel layers with respect to the sub-block element, and it is desired to generate a prediction block using the above settings, different settings may be made according to positions in the current sub-block block.

[00672] For example, it is assumed that the current block supports four horizontally divided subblocks. Then, the first sub-block may perform prediction and encoding using the nearest reference pixel of the current block, and the second sub-block may perform prediction and encoding using the nearest reference pixel of the current block and the data of the first sub-block.

[00673] In addition, the third subblock may perform prediction and encoding using data from the first and second subblocks, and the fourth subblock may perform prediction and encoding using data from the second and third subblocks.

[00674] The reference pixel filtering and reference pixel interpolation applied to each reference pixel layer (or sub-block) may use a single filter or may use different filters described above. In this case, the filters differ in the number of filter taps and filter coefficients. Additionally, filtering can also be applied in the same or different ways. Alternatively, reference pixel filtering and reference pixel interpolation are not performed separately, but may be implemented in a single filter. For example, when filtering reference pixels using a 6-tap interpolation filter instead of a 3-tap low-pass filter and a 4-tap interpolation filter, the filtering need not be performed twice.

[00675] As described above, various reference pixel configurations can be specified, and then prediction can be performed using multiple layers of reference pixels. In other various embodiments of the present invention, various combinations may be described.

[00676] An example of generating a prediction block will be described below.

[00677] It has been previously described that reference pixels for intra prediction can be divided into a variety of concepts. Instead of using multiple layers of reference pixels, a prediction block may be generated or adjusted using the first reference pixel and the second reference pixel in accordance with the prediction mode.

[00678] Examples with different application methods according to the prediction mode are described. However, this example can be applied to the case in which the current block is divided into many sub-blocks. That is, compared with using a reference pixel as the first reference pixel for an adjacent block of the current block, using a pixel located at a position opposite to the prediction mode direction or a position corresponding to the prediction mode direction as the second reference pixel if the current block is divided into multiple subblocks, the first reference pixel may be the top block. That is, in the present invention, the position of the first reference pixel can be changed in the example of generating a prediction block using a plurality of reference pixels.

[00679] Alternatively, the above method may not be used when the current block is divided into a plurality of sub-blocks and converted. The reason is that using a second reference pixel may result in low efficiency when arranging nearby pixels that include previously completed encoding.

[00680] That is, performing encoding by dividing the current block (transform block) into subblocks requires confirmation. Therefore, in the present invention, a prediction block can be generated or adjusted using the first reference pixel and the second reference pixel in accordance with the prediction mode if coding is performed by prediction, transformation, etc. at the original block size without division. If encoding is performed after division, generation or correction of a prediction block using the second reference pixel is prohibited.

[00681] If, when performing encoding, the second reference pixel is used after division according to the subblock division/decoding settings, a corresponding process can be performed by adjusting the position of the first reference pixel.

[00682] In FIG. 29 is a circuit diagram for explaining the configuration of reference pixels for intra prediction. The size and shape (M×N) of the current block for performing prediction can be obtained from the block division section and described based on the following assumptions: for performing intra prediction, a range of 4×4 - 256×256 is supported. Typically, intra prediction may be performed on prediction block elements, however, intra prediction may be performed on encoding block elements and transform block elements according to the settings of the block division section. After confirming the block information, the reference pixel configuration section may configure a reference pixel used for predicting the current block. In this case, the reference pixel processing may be performed by a temporary storage device (such as an <Array>, a main array or a auxiliary array, etc.), a reference pixel may be generated and deleted during each block intra prediction process, and the size of the temporary storage device can be determined according to the configuration of the reference pixel.

[00683] This example assumes that left block, top block, top left block, top right block, and bottom left block are used to predict the current block by centering on the current block. However, it is not limited to this, and a group of candidate blocks having other configurations can be used to predict the current block. For example, a candidate group for adjacent reference pixel blocks may be an example following a raster or Z-scan, and a portion of the candidate group may be removed according to the scan order or configured to include other candidate block groups (e.g., an additional top block configuration , bottom block, bottom right block, etc.). That is, the positions of adjacent blocks suitable as reference blocks may be changed in accordance with the scanning order or the like.

[00684] Alternatively, blocks (e.g., having corresponding coordinates according to the same coordinate or component compositional relationship in each color space) corresponding to the current block in other color spaces (e.g., if the current block belongs to Cr, other color spaces) may be used to predict the current block spaces correspond to Y or Cb). In addition, for ease of description, the description is made on the assumption that one block is configured in a predetermined position (left, top, top left, top right and bottom left), but at least one block can exist in a corresponding position. That is, a plurality of sub-blocks obtained by dividing a corresponding block may exist at a predetermined position.

[00685] Briefly, the adjacent region of the current block may be a reference pixel position for intra prediction of the current block, and the reference pixel position according to the prediction mode may be further considered to be a region corresponding to the current block in another color space. In addition to the above examples, a position of a reference pixel set according to a prediction mode, method, etc. can be determined. For example, if a prediction block is generated in a manner such as block matching, the position of the reference pixel may be considered to be the region in which encoding/decoding was completed before the current block of the current image, or the region included in the search range in the region where encoding/decoding was completed (for example , including the left side, or top side, or top left side and top right side of the current block).

[00686] As depicted in FIG. 29, a reference pixel for predicting the current block (M×N) can be configured by adjacent pixels of the left block, the top block, the top left block, the bottom right block and the bottom left block (Ref_L, Ref_T, Ref_TL, Ref_TR and Ref_BL in FIG. 7).

[00687] In this case, adjacent pixels can be classified by at least one layer of reference pixels: the nearest pixel is ref_0 (pixel value difference equal to 1, p(-1, -1) to p(2M-1, -1) , from p(-1, 0) to p(-1, 2N-1)), the next adjacent pixel (the difference in pixel values is 2, from p(-2, -2) to p(2M, -2), from p(-2, -1) to p(-2, 2N)) can be ref_1, and the next adjacent pixel (pixel value difference is 3, from p(-3, -3) to p(2M+1, -3 ), from p(-3, -2) to p(-3, 2N+1)) may be ref_2, etc. In more detail, ref_k represents a set of pixel values in which the difference in pixel values in adjacent blocks (in this example, Ref_TL, Ref_T, Ref_TR, Ref_L and Ref_BL) is equal to k+1. The description (or basic description) regarding the use of the reference pixel set ref_k herein is made based on the following assumption. Pixels having a pixel value difference of k+1 in Ref_TL, Ref_T, Ref_TR, Ref_L and Ref_BL are used as reference pixels and are used for the prediction unit, but the present invention is not limited to this. This means that in the set of reference pixels for predicting the current block, adjacent blocks may be the same or different.

[00688] For example, ref_0 (p(-1, -1) to p(2M-1, -1)) in Ref_TL, Ref_T and Ref_TR can also be used, ref_1 (p(-2, 0) to p(-2, N-1)) in Ref_L and used ref_2 (from p(-3, N) to p(-3, 2N+1)) in Ref_BL.

[00689] Additionally, one set of reference pixels refers to the set of reference pixels Ref_TL, Ref_T, Ref_TB, Ref_L and Ref_BL (i.e., derived from the adjacent block used for intra prediction of the current block), but in the following example, the set of reference pixels may be configured by some combination of reference pixels (e.g. Ref_T+Ref_TR, Ref_L+Ref_BL, Ref_T+Ref_TL+Ref_L, etc., or there may be a case in which a block at each position is configured by sub-blocks, i.e. Ref_T0+Ref_T1 , Ref_L0+Ref_TL+Ref_T, etc.).

[00690] The present invention is described under the assumption that there are no more than three sets of reference pixels, however, it is not limited to this, and more sets of reference pixels (k equal to 3 or more) can be used. In this case, the supported reference pixel set (or the maximum number of sets, called candidate reference pixel group in the following examples) can be determined according to encoding/decoding settings (eg, size, block shape, prediction mode, image type, color component, and etc.).

[00691] In the present description, a case is assumed in which a subscript (incremented by 1 from 0) is assigned from the nearest set of reference pixels, but the present invention is not limited to this. In addition, the related reference pixel configuration information described below may be generated by the above-described index settings (binarization of assigning a short bit to a small index in the case of selecting one of a plurality of reference pixel sets, etc.), but the present invention is not limited to this.

[00692] Typically, the nearest pixel of an adjacent block (in this example, reference pixel layer ref_0) may be configured as a reference pixel, but other pixels may be configured as reference pixels according to the encoding/decoding settings. If other reference pixel layers or at least one reference pixel layer are used, prediction accuracy can be improved, thereby improving coding efficiency. In this case, there may be different settings related to the setting of the reference pixel layer.

[00693] For example, the set of reference pixels used for intra prediction may be implicitly determined, or information associated with the set of reference pixels used may be explicitly generated. In detail, at least one predefined set of pixels may be configured as reference pixels, or at least one set of reference pixels determined using the reference pixel set selection information may be configured as reference pixels. Using the above process, a set of reference pixels (eg, ref_0, ref_1, ref_2, ref_0+ref_1, ref_0+ref_2, ref_1+ref_2, ref_0+ref_1+ref_2) can be configured as reference pixels for the current block.

[00694] In addition, it is possible to distinguish between a case in which the number of reference pixel sets configured as reference pixels is 1 and a case in which the number of reference pixel sets configured as reference pixels is two or more. The first case represents a case in which pixels in one set of reference pixels are used to generate a prediction block, while the latter case represents a case in which at least one pixel is used to generate a prediction block (for example, if two or more reference pixel sets - a value derived from the median, weighted average, etc. of pixel values (this value may also be a value derived from one or more pixels in each reference pixel set), in each reference pixel set may be value derived from one or more pixels).

[00695] For example, a prediction block may be generated using a reference pixel obtained by weighting the sum of pixels in a first set of reference pixels (ref_0 in this example) and pixels in a second set of reference pixels (ref_1 in this example). In this case, according to the prediction mode (eg, the directional prediction mode), the pixels to which the weighted sum is applied in each reference pixel layer may be not only integer element pixels, but also decimal element pixels. Alternatively, weighted values (eg, 7:1, 3:1, 2:1, 1:1, etc.) may be respectively applied to the prediction block obtained by using the pixels in the first set of reference pixels as reference pixels, and a prediction block obtained by using the pixels in the second set of reference pixels to obtain a prediction block.

[00696] Assuming the case of reference pixel configuration information generated explicitly, reference information enabling adaptive reference pixel configuration (in this example, adaptive_intra_ref_pixel_enabled_flag) may appear in video, sequence, frame, slice, tile, etc. elements. d.

[00697] If the indication information indicates that adaptive reference pixel configuration is enabled (in this example, adaptive_intra_ref_sample_enabled_flag=1), the adaptive reference pixel configuration information (in this example, adaptive_intra_ref_sample_flag) may appear in frame, slice, tile, block, etc. elements .d.

[00698] If the configuration information means that adaptive reference pixel configuration is enabled (in this example, adaptive_intra_ref_sample_flag=1), the associated reference pixel configuration information (for example, reference pixel set selection information, etc., in this example, intra_ref_idx) can appear in frame, slice, tile, block, etc. elements.

[00699] In this case, if the adaptive configuration of the reference pixels is not enabled, or the configuration is not an adaptive configuration of the reference pixels, the reference pixel can be configured according to a predetermined setting. In general, an example of this may be, but is not limited to, a case in which the nearest pixel of an adjacent block is configured as a reference pixel, various cases may occur (for example, a case in which ref_0 and ref_1 are configured as reference pixels, and a prediction pixel value is generated by performing summation of weighted values or the like with respect to ref_0 and ref_1, etc.; that is, the implicit case).

[00700] Moreover, in addition to the above-described predefined case (eg, case ref_0), related reference pixel configuration information (eg, reference pixel set selection information, etc.) may be configured, but not limited to, by a group candidates (for example, ref_1, ref_2, ref_3, etc.).

[00701] In the above example, the description is based on a hierarchical structure starting from the top layer element, but is not limited to this. In addition, in some cases, related information may be defined implicitly. For example, as described above, in some cases, related information may appear in accordance with encoding/decoding settings, in some cases, related information is implicitly determined, and in some cases, a combined case may occur.

[00702] Some cases of reference pixel configurations are described using the above examples, which can be combined with various encoding/decoding information, etc. to define intra prediction settings. In this case, the encoding/decoding information contains the image type (I/P/B), color component, current block shape and size, prediction mode (prediction mode type (directional or omnidirectional)), prediction mode direction (vertical, horizontal, diagonal 1, diagonal 2, etc.) etc., and the intra prediction settings (in this example, the reference pixel configuration settings) can be determined according to the encoding/decoding information of the adjacent block and a combination of the encoding/decoding information current block and adjacent block.

[00703] In FIG. 30 is a schematic diagram regarding the configuration of reference pixels.

[00704] In image a of FIG. 30 shows a case in which a set of reference pixels is configured as a reference pixel, and a subsequent intra prediction process (reference pixel generation, reference pixel filtering, reference pixel interpolation, prediction block generation, post-processing filtering, etc.; some intra prediction processes can be configured adaptively according to the configuration of a set of reference pixels) can be performed after configuring ref_0 as a reference pixel. For example, reference pixel set information is not generated for one reference pixel set, and an intra prediction process may be performed in accordance with the undirected mode.

[00705] In image b of FIG. 30 shows a case in which at most two sets of reference pixels are specified as reference pixels, and the subsequent intra prediction process can be performed after configuring ref_0+ref_1 (“and” in the figure) as reference pixels. For example, although there are a plurality of reference pixel sets but no reference pixel set information is generated, the intra prediction process may be performed in accordance with a prediction mode (in this example, upper left to lower left or lower left). corner to the top right corner).

[00706] In image c of FIG. 30 illustrates a case in which at most one set of reference pixels is specified as a reference pixel, and the subsequent intra prediction process can be performed after configuring one of ref_0, ref_1 and ref_2 (“or” in the figure) as reference pixels. For example, information about a set of reference pixels is generated using a plurality of sets of reference pixels, and intra prediction processing may be performed in accordance with certain prediction modes (in this example, from the upper left corner to the lower right corner).

[00707] Briefly, in images b and c of FIG. 30 shows cases in which two and three sets of reference pixels are supported, respectively (in other words, two and three groups of candidate reference pixels, respectively), image b shows at most two sets of reference pixels configured by reference pixels (e.g., derived from the weighted average of pixel values from each set of reference pixels, etc.), and image c represents at most one set of reference pixels configured with reference pixels (eg, derived from the pixel values of a selected set of reference pixels from three candidate groups).

[00708] In FIG. 31 is a schematic diagram of the configuration of reference pixels.

[00709] In image a of FIG. 31 shows a case in which the candidate reference pixel group is one set of reference pixels when the block size is 64×64 or more. In image b of FIG. 31 shows a case in which the candidate reference pixel groups are two sets of reference pixels (which means at most two sets of reference pixels for the reference pixels; that is, it is clear that both cases are possible, which are shown in images b and c of FIG. 30; the same case is presented below) when the block size is greater than 16x16 and less than 64x64. In image c of FIG. 31 shows a case in which the candidate reference pixel groups are three sets of reference pixels (meaning at most three sets of reference pixels for the reference pixels) when the block size is less than 16×16. In the present example, since the current block is larger, the size of the adjacent block is more likely to be smaller, which may result from partitioning due to other image characteristics. Therefore, to avoid making predictions from pixels at a large distance from the pixel value of the current block, it is assumed that since the block is larger, the number of reference pixel set candidates is reduced, but the opposite case can also be assumed. The present invention is not limited to this. Various examples of changes can be implemented.

[00710] In FIG. 32 is a schematic diagram regarding the configuration of reference pixels.

[00711] In FIG. 32 depicts a case in which when the current block is rectangular (horizontally elongated in this example), the candidate reference pixel groups are a plurality of reference pixel sets on the longer side, and the candidate reference pixel group is one reference pixel set on the shorter side. side. In this example, it is assumed that one set of reference pixels is configured on the shorter side, but it is understood that there are fewer configurations than on the longer side, and there may also be a large number of configurations otherwise. This example is intended to prevent, but not limit, the case in which, when a block is rectangular, a short-length reference pixel is often further away from the current block, thereby reducing prediction accuracy.

[00712] For example, in the case of a directional mode predicted using reference pixels on the top and top right sides of a block, the prediction can be performed using multiple sets of reference pixels (both cases are possible, which are shown in images b and c of Fig. 30) , and in the case of a directional mode predicted using the reference pixels of the left and lower left sides of the block, the prediction can be performed using a single set of reference pixels. That is, there may be a case in which a set of reference pixels is determined adaptively in accordance with adjacent blocks in one block.

[00713] As an example of a case in which one of a plurality of sets of reference pixels is configured as reference pixels, when each set of reference pixels is the same or similar, generating reference pixel configuration information (for example, reference pixel selection information, resolution information adaptive reference pixels, etc.) may represent a case in which information appears repeatedly. For example, if it is determined that the distribution characteristics of reference pixels (for example, they are determined by the mean and variance of each set of reference pixels; as an example, they can be determined by comparing the value obtained in the above process with the threshold value <Threshold>; that is, If it is determined that the same or nearly similar prediction block is generated, no matter which set of reference pixels is used, the associated information may be omitted; in this example, this may be limited to the comparison made for the last selected prediction mode) of each set of reference pixels are the same or similar, information about the configuration of the reference pixels may be omitted. In this case, the reference pixels may be configured in a predetermined manner (eg, the nearest set of reference pixels). In aspects of determining whether to receive reference pixel configuration information by receiving intra prediction information (eg, intra prediction mode information), the decoder may be the same as the encoder, and based on this determination, whether to receive the information may be determined. about the configuration of reference pixels.

[00714] Although various examples show a case in which multiple sets of reference pixels are configured as reference pixels, it is not limited to them. Various converted examples may occur and may be combined with other, additional configurations.

[00715] The reference pixel configuration section for intra prediction may include a reference pixel generation section, a reference pixel interpolation section, a reference pixel filtering section, etc. and may have all or part of the above configurations.

[00716] The reference pixel configuration section is configured to confirm the availability of reference pixels for the purpose of classifying available reference pixels and unavailable reference pixels. For example, if a block at a predetermined position (or a reference pixel candidate block) is available, then the corresponding block can be used as a reference pixel, and if it is not available, that block cannot be used as a reference pixel.

[00717] If at least one of the following conditions is satisfied, it is determined that the reference pixel is unavailable. For example, a reference pixel is defined as unreachable if one of the conditions is satisfied that the reference pixel is outside the frame boundary, it does not belong to the same division block as the current block (for example, slice, tile, etc.), encoding /decoding is not complete and usage is limited according to encoding/decoding. That is, if none of the above conditions are satisfied, it is determined that the reference pixel is available.

[00718] Additionally, the use of reference pixels may be limited by encoding/decoding settings. For example, the use of reference pixels may be constrained in accordance with the performance of constrained intra prediction (eg, constrained_intra_pred_flag). Limited intra prediction may be performed when error-tolerant encoding/decoding needs to be performed with respect to external factors, such as the communication environment, if an attempt is made to prohibit the use of blocks reconstructed by referring to other images as reference pixels.

[00719] According to the availability of a reference pixel, candidate reference pixel blocks can be classified into a case in which all candidate reference pixel blocks can be used, a case in which some reference pixels can be used, and a case in which all reference pixels not available. Except in the case in which all reference pixel candidate blocks may be used, in other cases reference pixels not available at the candidate block position may be filled or generated.

[00720] If a reference pixel candidate block can be used, a pixel at a predetermined block position (in this example, the pixel is assumed to be adjacent to the current block) can be included in the reference pixel storage of the current block.

[00721] If a reference pixel candidate block cannot be used, pixels obtained by the reference pixel generation process may be included in the reference pixel memory of the current block.

[00722] Briefly, if a reference pixel candidate block is in an available state, a reference pixel can be configured, and if a reference pixel candidate block is in an unavailable state, a reference pixel can be generated.

[00723] The reference pixel filtering section typically uses a low pass filter (such as a 3-tap filter and a 5-tap filter, e.g. [1, 2, 1]/4 and [2, 3, 6, 3, 2]/ 16) to perform anti-aliasing as the main purpose, but other types of filters (such as high-pass filter) can be used according to the purpose of the filters (for example, increasing clarity, etc.). The present description emphasizes that filtering is performed for the purpose of smoothing to reduce quality degradation during the encoding/decoding process.

[00724] The execution of reference pixel filtering can be determined in accordance with the encoding/decoding settings. That is, filtering may or may not be applied to the reference pixels. However, such a uniform filtering operation may have the disadvantage that some image characteristics may not be reflected, and it may be advantageous to improve encoding performance by performing filtering based on information such as encoding/decoding information reflecting some image characteristics.

[00725] Image characteristics can be determined not only according to image type (I/P/B), color component (Y/Cb/Cr), quantization parameter, encoding/decoding information of the current block (e.g., size, shape, division information, prediction mode, etc.), but also in accordance with the encoding/decoding information of adjacent blocks, the combination of encoding/decoding information of the current block and adjacent blocks, etc. In addition, determination (eg, determining whether the reference pixel area is a flat area or a discontinuous area, etc.) can be performed in accordance with the distribution characteristics of the reference pixels (eg, dispersion, standard deviation, etc. of the reference pixel area pixels). Thus, if the image characteristic information can be confirmed, the application of reference pixel filtering can be specified in advance.

[00726] Alternatively, filtering of reference pixels can be specified explicitly. For example, information about whether to apply filtering may be generated. In this case, filter selection information is not generated if there is one filter, or may be generated if there are multiple candidate filter groups.

[00727] Although the above examples described both implicit and explicit settings for filtering reference pixels, there may also be combined cases, e.g., in some cases the use of settings is explicitly specified, and in other cases the use of settings in an implicit form. In this case, the expression “implicit settings” means that information about the reference pixel filter (eg, whether to apply filtering and filter category information) can be obtained at the decoder.

[00728] The reference pixel interpolation section is configured to generate reference pixels in a decimal element by linearly interpolating the reference pixels. Although the process is described herein as part of the reference pixel configuration section, it can be understood as a component configured to be included in the prediction block generation section and execution before generating the prediction block.

[00729] In addition, although the reference pixel interpolation section is assumed to be a separate component from the preceding reference pixel filtering section, they may be configured to be combined into one component. It may also be a configuration in which distortion is generated in a reference pixel by applying a plurality of filters in the reference pixel interpolation section and the reference pixel filtering section.

[00730] In some prediction modes (e.g., horizontal, vertical, some diagonal modes <45 degree angle modes such as diagonal bottom right, diagonal bottom left, and diagonal top right>, omnidirectional modes, color modes, color copy modes, and etc.; that is, in modes where decimal interpolation is not required when generating a prediction block), the reference pixel interpolation process may not be performed, and it may be performed in other prediction modes (a mode where decimal interpolation when generating a prediction block is required).

[00731] The interpolation accuracy (for example, pixel elements such as 1, 1/2, 1/4, 1/8, 1/16, 1/32 and 1/64) can be determined in accordance with the prediction mode (or directionality prediction mode). For example, a prediction mode that forms an angle of 45 degrees does not require an interpolation process, but a prediction mode that forms an angle of 22.5 degrees or 67.5 degrees requires interpolation in 1/2 pixel elements. As described above, according to the prediction mode, at least one interpolation precision and a maximum interpolation precision can be determined.

[00732] To interpolate the reference pixels, a predefined filter may be used (e.g., a 2-tap linear interpolation filter, i.e., only that interpolation filter is used in all cases), and one of a variety of candidate interpolation filter groups may be used (e.g., 4-tap cubic filter, 4-tap Gaussian filter, 6-tap Wiener filter and 8-tap Kalman filter; that is, it is determined that an interpolation filter is used, applied according to the encoding/decoding settings). In this case, the interpolation filter can be distinguished by differences in the number of taps (i.e., the number of pixels to which filtering is applied), filter coefficients, etc.

[00733] The interpolation may include performance examples in stages, for example, in order from low precision to high precision (eg, 1/2->1/4-1/8), as well as uniform performance examples. In the first case, interpolation refers to performing interpolation (i.e. it means that not only integer elements are used for interpolation, but also decimal elements) based on integer element pixels and decimal element pixels (in this example, referring to pixels, for which were previously interpolated based on a lower precision than the pixel currently being interpolated). In the latter case, interpolation means that the interpolation is performed based on the pixels of integer elements (i.e., it means that only the pixels of integer elements are used for interpolation).

[00734] If one of multiple groups of candidate filter sections is used, filter selection information may be generated explicitly or determined implicitly and may be determined in accordance with encoding/decoding settings (e.g., interpolation precision, block size and shape, mode predictions, etc.). In this case, the element that is explicitly generated corresponds to a video, sequence, frame, slice, tile, block, etc.

[00735] The prediction block generating section is configured to generate a prediction block in accordance with at least one prediction mode, and is configured to use a reference pixel based on the prediction mode. In this case, the reference pixel can be used in methods (directional mode) such as extrapolation in accordance with the prediction mode, and can be used in methods (non-directional mode) such as interpolation or averaging (DC) or copying.

[00736] In addition, a prediction block may be generated by copying reference pixels. When copying reference pixels, more than one prediction pixel may be generated by copying one reference pixel, or more than one prediction pixel may be generated by copying more than one reference pixel, and the number of copied reference pixels is less than or equal to the number of copied prediction pixels.

[00737] In addition, although a prediction block generally consists of one prediction block obtained by a prediction block generation process, the following example may be included: a final prediction block is obtained by obtaining a plurality of prediction blocks and applying the prediction blocks to the plurality of prediction blocks. weighted summation or the like. Here, the expression “multiple prediction blocks” may refer to prediction blocks obtained from a set of reference pixels, and in other cases may refer to the same prediction block.

[00738] The prediction mode determination section performs an optimal mode selection process in a plurality of candidate prediction mode groups. To determine the mode with the optimal encoding cost to generate the number of bits of the corresponding mode, block distortion technology (eg, current block distortion and reconstructed block distortion; SAD, SSD, etc.) and random distortion technology can be generally considered. The prediction block generated based on the prediction mode determined by the above process may be sent to the subtraction section and the addition section.

[00739] The prediction mode encoding section is configured to encode the prediction mode selected by the prediction mode determining section. In a group of candidate prediction modes, index information corresponding to a prediction mode may be encoded, or a prediction mode may be predicted to encode information associated therewith. That is, the first case represents a method of directly encoding a prediction mode without performing prediction, and the last case represents a method of predicting a prediction mode such that prediction information of the encoding mode and information obtained based on the prediction information are encoded. Moreover, the first example is an example that can be applied to a chroma component, and the last example is an example that can be applied to a luminance component. They are not limited to this and can also be used in other cases.

[00740] In the case of performing prediction and encoding with respect to a prediction mode, the prediction value (or prediction information) of the prediction mode may be referred to as MPM. In this case, a preset prediction mode (e.g., DC mode, planar mode, vertical mode, horizontal mode, diagonal mode, etc.) or a spatially adjacent block prediction mode (e.g., left block, top block, top left block, top right block, bottom left block, etc.). In this example, the diagonal mode may represent a diagonally up-right, diagonally down-right, and diagonally down-left mode, which may correspond to mode 9, mode 34, and mode 66 in FIG. 9.

[00741] In addition, a mode obtained from modes included in a candidate MPM group may be configured as a candidate MPM group. For example, in the case of a directional mode included in a group of candidate MRMs, a mode with a difference a of the intervals between modes (for example, a is a non-zero integer such as 1, -1, 2 or -2; in case in Fig. 9 there was mode 10 is included, derived modes are mode 9, mode 11, mode 8, mode 12, etc.) is re-included (or additionally included) in the group of MRM candidates.

[00742] The above example may correspond to a case in which the MPM candidate group is configured in a plurality of modes, wherein the configuration of the MPM candidate group (for example, the number of MPM candidate groups and the priority of the configuration) can be determined in accordance with the encoding/decoding settings (eg, candidate prediction mode group, image type, block size, block shape, etc.) may be configured to include at least one mode.

[00743] The prediction mode for configuring a group of MPM candidates may have priority. The order of prediction modes included in the MPM candidate group can be determined according to priority, and the configuration of the MPM candidate group can be completed if the number of MPM candidate groups is filled according to the priority. In this case, the priority can be determined in the order of: prediction mode of a spatially adjacent block, a predefined prediction mode, and a mode derived from the prediction mode originally included in the MPM candidate group, but other modifications are possible.

[00744] For example, in spatially contiguous blocks, block prediction modes may be included in a candidate group in the order left-upper-lower-left-upper-right-upper-left block, etc. In the predefined prediction modes, the prediction modes may be included in the candidate group in the order DC-planar-vertical-horizontal mode etc., and the prediction mode obtained by adding +1, -1 or etc. to the included mode is included in the candidate group Alternatively, the prediction modes can be included in a candidate group with priority left-upper-DC-planar-lower-left-upper-right-upper-left-left+1-left-1-upper+1, etc.

[00745] If prediction mode encoding of the current block is performed using the MPM, information about whether the prediction mode matches the MPM (eg, most_probable_mode_flag) may be generated.

[00746] If the prediction mode matches the MPM, (eg, most_probable_mode_flag=1), MPM index information (eg, mpm_idx) may be additionally generated according to the MPM configuration. For example, if the MPM is executed as a single prediction mode, no additional MPM index information is generated, but if the MPM is executed as a plurality of prediction modes, index information corresponding to the prediction mode of the current block may be generated in a group of candidate MPMs.

[00747] If the prediction mode is not the same as the MPM (e.g., most_probable_mode_flag=0), in the remaining candidate prediction mode group (or non-MPM candidate mode group) other than the MPM candidate group in the candidate prediction mode groups, non-MPM mode index information (eg, non_mpm_idx) corresponding to the current mode prediction mode may be generated, which may be an example of a case in which the non-MPM mode is configured as one group.

[00748] If the non-MPM candidate mode group consists of multiple groups, information about which group the prediction mode of the current block belongs to can be generated. For example, a non-MPM mode consists of groups A and B, if the prediction mode of the current block is the same as the prediction mode of group A (for example, non_mpm_A_flag=1), index information corresponding to the prediction mode of the current block can be generated in group A candidates, and if there is no match (eg, non_mpm_A_flag=0), index information corresponding to the prediction mode of the current block may be generated in the remaining candidate prediction mode groups (or candidate group B). As in the above example, the non-MPM mode may be configured as at least one candidate prediction mode group (or set), and the configuration of the non-MPM modes may be determined in accordance with the candidate prediction mode group . For example, if there are no more than 35 candidate prediction mode groups, there may be one non-MPM mode, and in other cases there are two or more non-MPM modes.

[00749] In this case, group A may configure as a candidate group a mode other than the MPM candidate group having the highest probability of matching the prediction mode of the current block. For example, the next sequential prediction mode not included in the MPM candidate group may be included in group A, or a prediction mode having a directionality from a predetermined interval may be included in group A.

[00750] If the non-MPM mode is composed of many groups, as in the above example, the number of prediction modes is large, and the prediction mode is not predicted by the MPM, the non-MPM mode is supported to reduce the number of mode bits.

[00751] If prediction mode encoding (or prediction mode decoding) of the current block is performed using MPM, the binarization table applied to each prediction mode candidate group (e.g., MPM candidate mode group, non-candidate mode group MPM, etc.) can be generated separately, and the binarization method applied to each candidate group can also be applied separately.

[00752] In the above example, terms such as “MPM candidate group” and “non-MPM candidate mode group” are just some of the terms used in the present invention and are not limited to them. Specifically, these terms represent information about the category to which a prediction mode belongs after dividing the prediction modes in the current frame into a plurality of categories, and information about a mode within a category. As other expressions, they may also be used for terms such as "major MPM candidate group" and "minor MPM candidate group".

[00753] Prediction-related information that is generated by the prediction mode encoding section may be transmitted to the encoding section and included in the bit stream.

[00754] If more than one set of reference pixels is configured as a candidate reference pixel group, a case in which one set of reference pixels is used and a case in which more than two sets of reference pixels are used can be distinguished below.

[00755] (1) Using one set of reference pixels.

[00756] In this example, it is assumed that when multiple sets of reference pixels are specified as candidate groups, one set of reference pixels (one of ref_0, ref_1 and ref_2 in FIG. 29) is selected for intra prediction.

[00757] If intra prediction is performed using one set of reference pixels, the following situation may occur.

[00758] A prediction block P may be generated using ref* obtained using a set of ref reference pixels and a prediction preprocessing procedure such as reference pixel generation, reference pixel filtering, and reference pixel interpolation.

[00759] For example, 5-tap low-pass filtering is applied to pixels located at ref by the reference pixel filtering section, and 6-tap low-pass filtering is applied to pixels located at ref' (i.e., pixels after reference pixel filtering). linear interpolation filtering using the reference pixel interpolation section. Moreover, a prediction block may be generated using ref* obtained in the above process.

[00760] A prediction pre-processing procedure using a single set of reference pixels is described below.

[00761] For example, when using reference pixel set ref_2 in FIG. 29, if the positions Ref_TL and Ref_TR can be used as reference pixels, and the position Ref_T cannot be used as a reference pixel, pixels at positions P(0, -3) to P(n-1, -3) Ref_T can be generated by adjacent pixels at positions P(-1, -3) to P(n, -3) from the available reference pixels and configured as reference pixels.

[00762] After configuring the reference pixels using the above process, components such as the reference pixel filtering section and the reference pixel interpolation section can be performed before generating the prediction block.

[00763] In the case of the reference pixel filtering section, filtering can be applied on adjacent pixels centered on the target pixel, and generally, the larger the number of pixels that are applied to the filter, the more precise the filtering effect (eg, smoothing, sharpening, etc.) .) can be achieved.

[00764] In the case of the reference pixel interpolation section, filtering can be applied in adjacent pixels centered on the pixels to be interpolated, and the larger the number of pixels that are applied to the filter, the more accurate the filtering effect can be generated.

[00765] Both of these steps serve as a process for performing filtering, and depending on situations, unnecessary filtering effects may be generated. That is, when applying filtering at each stage, in case of adverse effects when applying filtering at another stage, the desired effect may also appear.

[00766] For example, during the reference pixel interpolation process, the interpolation target decimal pixels may apply filtering at adjacent integer pixels if this example assumes that the previous step applies reference pixel filtering (i.e., applied to integer element pixels), quantization error of each integer pixel can be reduced by filtering the reference pixels, or it is also possible to create a case in which the quantization error is instead further incorporated into the interpolated pixel by using that pixel in the reference pixel interpolation process.

[00767] (S1. Smoothing Ref)

[00768] m*=v0xl'+v1xm'+v2xn'

[00769] m*=m+k1

[00770] (m is the original pixel, m* is the filtered pixel, m' is the pixel before filtering, 1' and n' are adjacent pixels before filtering, v is the filter coefficient, and k1 is the quantization error)

[00771] (S2. Interpolation process)

[00772] z*=(w0xa'+w1xb'+w2xc'+w3xd'+w4xe'+w5xf')

[00773] z*=z+k2

[00774] (z is the original pixel at the specified position, z* is the interpolated pixel; a'-f' are adjacent pixels <filtering not performed>, w is the filter coefficient, and k2 is the quantization error)

[00775] (S3. Ref smoothing + interpolation process)

[00776] z**=(w0xa*+w1xb*+w2xc*+w3xd*+w4xe*+w5xf*)

[00777] z**=z+k3

[00778] (z is the original pixel at the specified position, and z** is the interpolated pixel; a*-f* are adjacent filtered pixels, w is the filter coefficient, and k3 is the quantization error)

[00779] In the above equations, the input pixel value to the reference pixel filtering process S1 is the adjacent pixel of the adjacent block for which encoding/decoding is completed, and the output value obtained by the above process is the pixel having a high probability of being close to the source pixel for reducing the quantization error introduced during encoding/decoding.

[00780] In addition, the input pixel value to the reference pixel interpolation process S2 is an adjacent pixel of an adjacent block for which encoding/decoding is completed, and the output value obtained by the above process is a pixel having a high probability of being close to the original pixel value in specified pixel position. With this process, weighted summation is applied to adjacent pixels of adjacent blocks containing the quantization error to obtain interpolated pixels (i.e., assuming no filtering is applied to reduce the quantization error, the quantization error can also be reduced by this process). and thus it is possible to obtain pixels that reduce the quantization error and are close to the original pixel. That is, not only decimal element pixels may be generated, but the effect of the low-pass filtering section may also occur.

[00781] On the other hand, in the case of S3, where the processes are executed sequentially, it is necessary to consider whether the effect that is desired to be obtained in the processes can be maintained. That is, it is due to the fact that the implementation of filtering (performing only one or two filters, etc.), the type of filter (using an improved filter or a slightly improved filter; that is, even if the process generates a satisfactory effect, this effect is not achieved in other processes or, conversely, an unsatisfactory effect is obtained), adding a filter outlet, etc. do not necessarily guarantee a satisfactory filtration effect.

[00782] (2) Using more reference pixel sets.

[00783] In this example, more than two sets of reference pixels (more than two of ref_1, ref_2 and ref_3 in FIG. 29) are selected for intra prediction when multiple sets of reference pixels are configured as candidate groups.

[00784] If intra prediction is performed using multiple sets of reference pixels, the following situation may occur.

[00785] <1> As shown in image a of FIG. 33, the first prediction block may be generated by the reference pixel set ref_A. That is, the prediction block PA may be generated using ref_A* obtained using ref_A and a prediction preprocessing procedure such as reference pixel generation, reference pixel filtering, and reference pixel interpolation. In addition, a prediction block PB may be generated using ref_B* obtained by a prediction preprocessing procedure for ref_B.

[00786] A final prediction block P may be generated by the resulting plurality of prediction blocks.

[00787] For example, 3-tap low-pass filtering is applied to the pixels in ref_A by the reference pixel filtering section, and 4-tap cubic filtering is applied to the pixels in ref_A' (ie, the pixels after the reference pixels are filtered) by the reference pixels. In addition, 5-tap low-pass filtering is applied to pixels located in ref_B, and 6-tap linear interpolation filtering can be applied to pixels located in ref_B' (ie, pixels after reference pixel filtering).

[00788] In addition, each prediction block is generated using ref_A* and ref_B* obtained using the above process, and then the prediction block is generated by applying a weighted average (e.g., applying a high weighting value, such as 3:1, to the prediction block , adjacent to the current block), etc.

[00789] <2> As shown in image b of FIG. 33, a prediction block may be generated by reference pixel sets ref_A and ref_B. In this case, the prediction block P may be generated using ref_A* obtained using ref_A and ref_B and using a prediction preprocessing procedure such as reference pixel generation, reference pixel filtering, and reference pixel interpolation.

[00790] For example, 3-tap low-pass filtering may be applied to pixels located at ref_A using a reference pixel filtering section, and 4-tap cubic filtering may be applied to pixels located at ref_A' using a reference pixel interpolation section. In addition, 5-tap low-pass filtering may be applied to pixels located at ref_B, and 2-tap linear interpolation filtering may be applied to pixels located at ref_B'.

[00791] In addition, a prediction block may be generated after receiving ref* using ref_A* and ref_B* obtained in the above process. That is, after obtaining the pixel values corresponding to the directionality of the intra prediction mode in each set of reference pixels (for example, pa in ref_A* and pb in ref_B*) according to the prediction mode, a weighted average (for example, pa×A+pb) can be applied ×B) to generate a prediction block.

[00792] To generate a prediction block using methods <1> and <2> (<1> is a method of applying a weighted average between prediction blocks after generating those prediction blocks in each set of reference pixels, <2> is a method of applying a weighted average between pixels in the process of generating a prediction block; that is, the same or similar results are obtained, but the process may differ) more than two sets of pixels may be used.

[00793] The procedure for predicting pre-processing when using more than two sets of reference pixels is described below.

[00794] For example, when using reference pixel sets ref_1 and ref_2 in FIG. 29, if the positions Ref_TL and Ref_TR can be used as reference pixels, and the position Ref_T cannot be used as reference pixels, pixels P(0, -1) to P(n-1, -1) at the position Ref_T are generated in ref_1 by adjacent pixels at P(-1, -1) and P(n, -1) from the available reference pixels of the reference pixel set ref_1, and pixels P(0, -2) to P(n-1, -2) at position Ref_T may be generated in ref_2 by adjacent pixels in P(-1, -2) and P(n, -2) from the available reference pixels of the reference pixel set ref_2.

[00795] Alternatively, a prediction block may be generated using the available pixels in ref_1 and ref_2 at the positions of the unavailable pixels in ref_1, and the prediction block may also be generated using the available pixels in ref_2 and ref_1, as described above, at the positions of the unavailable pixels in ref_2.

[00796] In the case of a reference pixel filtering section, filtering may be applied to adjacent pixels centered on a target pixel, and in the case of a reference pixel interpolation section, filtering may be applied to adjacent pixels centered on a pixel to be interpolated.

[00797] In this example, as also mentioned in the case of using one set of reference pixels in (1) to generate a prediction block, undesirable effects are generated when filtering is applied.

[00798] Following the procedure in (1), the following description is made under assumption <1> in (2).

[00799] (S4. Intra prediction process)

[00800 P=v0xP1+v1+P2

[00801] The above formula represents the process of obtaining a final prediction block by performing a weighted summation on the prediction blocks obtained using each set of reference pixels. That is, it is necessary to consider the part relating to obtaining prediction blocks using the values that are obtained by the S3 process in each set of reference pixels and applying weighted summation of the prediction blocks, whereby it is possible to improve the accuracy of the prediction block.

[00802] For the problems to be addressed by (1) and (2), the method may be a solution in which one of a plurality of candidate groups is explicitly selected (e.g., as a candidate group associated with reference pixel filtering, one of the following is selected: <no filtering, or 3-tap filtering, or 5-tap filtering>, as the candidate group associated with reference pixel interpolation, one of <4-tap filtering or 6-tap filtering> is selected, and The optimal way to define it implicitly is described below.

[00803] An intra prediction process in which a prediction block is generated using one set of reference pixels or using more than two sets of reference pixels is described through the following embodiments.

[00804] (3) Prediction pre-processing procedure when using one set of reference pixels

[00805] As shown in image a of FIG. 34, the predicted reference pixel may require a temporary storage device, which may contain a main array or a auxiliary array. This example assumes that the reference pixels are defined by the main array, as shown in the figure.

[00806] As shown in image a of FIG. 34, ref may be filled with pixels from the set of reference pixels used for prediction. In this case, to configure ref, reference pixels may be passed through a reference pixel filtering section after configuring or generating reference pixels, for example, by a reference pixel generation section. The reference pixels obtained by the reference pixel filtering section are represented as ref'. Then, reference pixels obtained by performing a reference pixel interpolation process with respect to ref' are represented as ref*, and a prediction block can be generated using ref*.

[00807] *An integer element pixel consists of ref', a decimal element pixel consists of ref* obtained by performing interpolation with respect to ref' (image b in Fig. 12).

[00808] As described in the above example, for ref* (an integer element pixel from ref* is the same as ref'), the reference pixel filtering process and the reference pixel interpolation process are performed sequentially, so that when applying the integer element pixel obtained by By using these processes, a reference pixel with less high precision can be obtained by interpolating decimal element pixels due to repeated filtering. Therefore, the reference pixel filtering process and the reference pixel interpolation process need to be performed separately.

[00809] For example, reference pixel filtering may be omitted and only reference pixel interpolation may be performed. In this case, the integer element pixel used for prediction may be an existing adjacent pixel to which no reference pixel filtering has been applied, and the decimal element pixel may be a pixel obtained by applying interpolation to existing adjacent integer element pixels.

[00810] *An integer element pixel consists of ref', a decimal element pixel consists of ref* obtained by performing interpolation using ref (image c in FIG. 34).

[00811] Alternatively, if interpolation is performed on decimal element pixels, ref may be used as the reference pixel instead of ref'. In this case, the integer element pixel used for prediction may be a pixel to which reference pixel filtering has not been applied, and the decimal element pixel may be a pixel to which interpolation is applied by using existing adjacent pixels as pixels before reference pixel filtering is performed.

[00812] *An integer element pixel consists of ref', a decimal element pixel consists of ref* obtained by performing interpolation using ref (image d in FIG. 34).

[00813] The number of filters applied to the pixels at each position in ref is depicted using images b-d in FIG. 34. In images c and d in FIG. 34 shows examples of configuring a reference pixel by applying at most one filter.

[00814] (4) Prediction pre-processing procedure when using more than two sets of reference pixels

[00815] For ease of description, assuming case <2> in (2) of the previous example, two sets of reference pixels are used to generate the prediction block.

[00816] After configuring ref_A, using the reference pixel filtering section, ref_A' can be obtained, and after performing the reference pixel interpolation process with respect to ref_A', ref_A* can be obtained. Moreover, in the case of ref_B, ref_B* can be obtained by ref_B', and ref_A* and ref_B* are used to generate a prediction block (ie, ref* in image b of FIG. 34). In this case, the prediction block may be generated using integer element pixels or decimal element pixels in ref_A* and ref_B* according to the prediction mode.

[00817] As described above, for ref_A* and ref_B*, the reference pixel filtering process and the reference pixel interpolation process are performed sequentially, so that when an integer element pixel obtained by these processes is applied to the decimal element pixel interpolation due to repeated filtering, a reference pixel with less high precision. In addition, since pixels located in more than two sets of reference pixels may further be filtered by weighted summation or the like, it is possible to perform filtering on the pixels too many times for the final prediction.

[00818] Various combinations of reference pixels for prediction pixels are shown below. For example, prediction pixels may be generated using two integer element pixels in ref_A and ref_B according to the directionality of the prediction mode (eg, vertical mode, horizontal mode, etc.), prediction pixels may be generated using one integer element pixel and one pixel decimal element (eg, directional mode, etc.), and prediction pixels may be generated using two pixels of decimal elements (eg, directional mode, etc.). This can be confirmed by images b-d in Figs. 35.

[00819] In the above case, as shown in image b of FIG. 34, under the assumption that applying filtering to a single set of reference pixels is considered as a case in which a weighted average is applied with other sets of reference pixels, the number of filterings applied in image b in FIG. 35 may be 2, the number of filters applied in image c of FIG. 35 may be 3, and the number of filters applied in image d in FIG. 35, can be 4.

[00820] For the above case, the following example can be applied.

[00821] For example, in each set of reference pixels, filtering of the reference pixels may be omitted, and only the reference pixel interpolation process may be performed. In this case, the integer element used for prediction may be an existing adjacent pixel to which no reference pixel filtering has been applied, and the decimal element pixel may be a pixel obtained by applying interpolation to existing adjacent integer element pixels.

[00822] In particular, in the case of filtering reference pixels, applying filtering to pixels similar to the target pixel can more effectively reduce the quantization error. In this example, the prediction is performed using more than two sets of reference pixels, which means that the directionality of the current block also exists at the boundary of the block that includes the reference pixel (that is, more than two sets of reference pixels adjacent to the current block). Therefore, as before, filtering is performed using only the nearest pixel regardless of the directionality of the current block's prediction mode, which is similar to filtering potentially different pixels based on the values of the target pixel and the source pixel.

[00823] Alternatively, the reference pixel filtering and reference pixel interpolation processes may be performed for each set of reference pixels. However, as shown in image b of FIG. 35, if the weighted average is applied only to the pixels of integer elements, pixels to which reference pixel filtering has been applied may be used, and as shown in image c of FIG. 35, if the weighted average is applied to integer element pixels and decimal element pixels, the integer element pixels used may use pixels to which reference pixel filtering has not been applied.

[00824] Using the above examples, the prediction pre-processing procedure is depicted for a case in which one set of reference pixels is used and for a case in which more than two sets of reference pixels are used.

[00825] In the above examples, although some cases are described in which it is assumed that adverse effects occur due to repeated use of the filter, it cannot determine only one characteristic of the image, and other variations may exist.

[00826] For example, for cases (3) and (4), it can be used either in a fixed manner (for example, regardless of a state such as the shape and size of the current block and the prediction mode) or adaptively (for example, determined in accordance with the state of the current block).

[00827] In the case of adaptive use of (3) and (4), the settings in (3) and (4) may be applied in whole or in part, and in some cases the counterexample may also be modified or applied.

[00828] As an example, in some modes (eg, vertical, horizontal, 45-degree, 135-degree diagonal modes, etc.) of case (3), 5-tap low-pass filtering can be performed. In this example, since the decimal interpolation process is not required, fine filtering can be performed to reduce the quantization error (assuming that filtering is more accurate with more taps in this example).

[00829] Alternatively, in some modes (eg, directional mode, etc.) 3-tap low-pass filtering and 6-tap Gaussian interpolation filtering may be performed in (3). In this example, the process of interpolation of decimal elements is required, and simple filtering can be done by applying filtering to the pixels of integer elements (for example, assuming that in the following cases, the filtering is simpler, that is, the types of filters are different, the number of pixels to which the filter is applied, is reduced and the number of taps is small) to reduce the quantization errors of multiple filterings (in this example, filtering of reference pixels is applied to pixels of integer elements, and filtering is applied when these pixels are used to interpolate pixels of decimal elements). That is, a case like b in FIG. 34 (although described as an existing case in the description of image b in FIG. 12, this example describes that case b can be applied instead of cases c and d in FIG. 34).

[00830] As an example, in (3), in the case of a block (eg, 32×32) that is larger than a predetermined size, 5-tap low-pass filtering may be performed and 4-tap cubic interpolation filtering may be performed, but the pixels applied when interpolating, may include pre-low-pass filtering pixels (i.e., integer element pixels) as input pixels. Moreover, in the case of a block that is smaller than a predetermined size, the same reference pixel filtering and reference pixel interpolation processes are performed as the same as the above process, but the pixels used in the interpolation may include low-pass filtered pixels as input pixels.

[00831] As an example, in some modes (e.g., vertical, horizontal, etc.) in (4), 5-tap low-pass filtering may be performed on each set of reference pixels (i.e., using a more precise filter than when using a 3-tap filter in other directional modes or using other filter types even if they contain the same number of taps). In this example, since interpolation is not required, filtering can be performed to reduce the quantization error. Alternatively, 5-tap low-pass filtering may be performed on a set of reference pixels adjacent to the current block, and 3-tap low-pass filtering may be performed on the next adjacent set of reference pixels. In this example, fine filtering can be performed on a set of reference pixels (this example assumes that weighted values are added to pixels near the current block). The reference pixel set assigns higher weights to more than two sets of reference pixels. Alternatively, 5-tap low-pass filtering is performed on a set of reference pixels adjacent to the current block, and no low-pass filtering is performed on the next adjacent set of reference pixels. It is clear that in this example, by centering on pixels from the higher weighted reference pixel set, low pass filtering is applied to pixels adjacent to the reference pixel set to which the pixel belongs, and to pixels adjacent to a pixel in other sets reference pixels (ie, if the prior art case is one-dimensional filtering, in this example it is clear that two-dimensional filtering is taking place).

[00832] In addition, in some modes (eg, directional mode, etc.) in (4), 3-tap low-pass filtering is performed on each set of reference pixels, 8-tap cubic interpolation filtering is performed on the set of reference pixels adjacent to the current block, and 2-tap linear interpolation filtering can be performed on the next adjacent set of reference pixels. Alternatively, instead of performing low pass filtering on each set of reference pixels, 6-tap Gaussian interpolation filtering is performed on a set of reference pixels adjacent to the current block, and 4-tap Gaussian interpolation filtering may be performed on the next adjacent set of reference pixels. Alternatively, 5-tap low-pass filtering may be performed on a set of reference pixels adjacent to the current block, 3-tap low-pass filtering may be performed on the next adjacent set of reference pixels, and 4-tap cubic interpolation filtering may be performed on each set of reference pixels. pixels. Alternatively, 3-tap low-pass filtering is performed on reference pixel set A adjacent to the current block, no low-pass filtering is performed on the next adjacent reference pixel set B, 8-tap Gaussian interpolation filtering is performed on reference pixel set A adjacent to current block, and 4-tap cubic interpolation filtering is performed on the next adjacent set B of reference pixels.

[00833] As an example, in (4), in the case of a block having a predetermined or larger size (eg, 64×64), 4-tap cubic interpolation filtering can be performed without performing low-pass filtering on each set of reference pixels. Additionally, in a block that is smaller than a predefined size and larger than a predefined or larger size (for example, 16x16 - 64x64), 3-tap low-pass filtering as well as 4-tap Gaussian interpolation filtering are performed on each set of reference pixels, but when the weighted averaging pixels consist only of a set of integer element pixels, the low-pass filtered pixels are used, and when the weighted averaging pixels consist of a combination of integer elements and decimal elements, the integer element pixels may use the pre-low pass filtering pixels. In addition, in a block that is smaller than a predefined size (16x16), 5-tap low-pass filtering and 6-tap cubic interpolation filtering are performed on each set of reference pixels, and the pixels are weighted for averaging, regardless of whether they are integer elements or decimal elements, can use low-pass filtered pixels.

[00834] According to the above example, various cases are depicted in which one set of reference pixels is used, and more than two sets of reference pixels are used, etc.

[00835] Regarding the prediction pre-processing procedure, processing may be performed explicitly. That is, it is possible to generate one kind of selection information regarding the use of one set of reference pixels or the use of more reference pixels, and it is also possible to generate another kind of selection information regarding the fact that for the filtering settings of the reference pixels, no filtering is performed, or filtering is performed using filter A or filter B, and it is possible to generate yet another kind of selection information regarding the use of filter A or filter B for reference pixel interpolation settings.

[00836] Alternatively, implicit processing may be performed on the prediction pre-processing procedure. That is, the number of reference pixel sets, reference pixel filtering settings, and reference pixel interpolation settings described above can be determined implicitly according to encoding information (states) such as block size, block shape, and prediction mode. In this case, if the number of reference pixel sets is determined to be two or more, it may be implicitly determined that the same reference pixel filtering or reference pixel interpolation setting or other setting is performed on a plurality of reference pixel sets.

[00837] Alternatively, mixed processing may be performed on the prediction pre-processing procedure. That is, in some cases implicit processing may be performed, and in other cases explicit processing may be performed. In this case, according to the encoding information, a reference to mixed processing can be determined. That is, the implicit processing or the explicit processing may be determined in accordance with a combination of at least one or more of a certain block size or shape or prediction mode.

[00838] In the present description, the case of implicit processing or mixed processing will be described. For both processes, the intra prediction setting can be configured based on encoding information (e.g., prediction preprocessing, etc., which was described above as having an adaptive configuration only in prediction preprocessing, but which also has an adaptive configuration in other processes intra prediction <a group of candidate intra prediction modes is configured in the following contents, that is, determined from encoding information such as the number of intra prediction modes and the prediction direction>).

[00839] The specified contents are arranged as follows.

[00840] (Encoder)

[00841] <1> Confirms the size and shape of the current block

[00842] - Setting up an intra prediction candidate mode group (i.e., defining the number of modes, angles, etc. that can be omitted if there is one candidate group)

[00843] <2> The size, shape and prediction mode of the current block are confirmed (at this point, the prediction mode is determined by the intra prediction mode candidate group determined in the above process)

[00844] - Setting up a set of reference pixels (i.e. using one or more than two sets)

[00845] - Reference pixel filtering setting (if there are more than two reference pixel sets, the filtering setting can be defined in each reference pixel set)

[00846] - Setting reference pixel interpolation (similarly, if there are more than two sets of reference pixels, interpolation settings can be defined in each set)

[00847] <3> Encoding information related to intra prediction (if selection information is generated due to the presence of multiple candidate groups in the prediction mode and settings of the above process, this information is also included in the intra prediction information).

[00848] (Decode)

[00849] <1> The size and shape of the current block are confirmed (in the previous step, the block information is analyzed by the block separating section, and the related information is confirmed)

[00850] - Intra prediction candidate mode group setting (prediction mode information is analyzed and restored according to the candidate group)

[00851] <2> Confirms the size, shape and prediction mode of the current block

[00852] - Setting reference pixels

[00853] - Setting filtering of reference pixels

[00854] - Setting the interpolation of reference pixels

[00855] <3> Decoding information related to intra prediction (prediction mode and other optional information; this information can be considered to be analyzed at this stage).

[00856] In the encoder, a group of candidate intra prediction modes may be confirmed according to the state of the current block. That is, it is determined which candidate group is used, and the determined candidate group contains a specific number of modes and specific mode configurations. Acknowledgment is trivial if all conditions of the candidate intra prediction mode groups are the same, but confirmation is required if more than two candidate intra prediction mode groups are used. That is, which candidate group is used can be learned according to the state of the current block, or which candidate group is used can be learned explicitly using the information.

[00857] Prediction mode numbers, etc. are assigned according to the specified process, but if the candidate prediction mode groups are different, directions or angles, etc. Each prediction mode differs according to the candidate groups, and therefore a process of unifying the candidate groups may be required. That is, No. 50 in the prediction mode of FIG. 9 may be a vertical mode, but No. 50 in another group of candidate prediction modes is not necessarily a vertical mode, so confirmation is required.

[00858] Therefore, it is described herein that operations, settings, etc. vary depending on the type of prediction mode.

[00859] For example, when the conditional statement “if (intramode==Vertical)” is used to determine the execution of intra prediction processing (e.g., reference pixel interpolation, reference pixel filtering, etc.), if “intramode” is No. 50, and a candidate prediction mode group is used, it can be directly specified to perform intra prediction processing, but since it is necessary to know the type of mode in the candidate intra prediction mode group (directed mode or non-directed mode; if it is a directed mode, it is determined whether it belongs to to vertical or horizontal mode, and if it is not a directional mode, it is determined whether there is a directional mode to generate a prediction block using only integer pixels, etc.), it can be entered into a conditional clause after confirming the direction of the above mode in the group candidate prediction modes. That is, if (intramode<x>==Vertical), it should be changed to such a process that mode x is vertical in the group of intra prediction mode candidates of mode x.

[00860] In addition, to confirm the intra prediction settings, it is necessary to confirm the state of the current block. In this case, the state of the current block may be determined according to at least one or more of size, shape, prediction mode, etc. current block. Reference pixel set, reference pixel filtering, reference pixel interpolation, etc. are set in accordance with the state of the current block. That is, the number of reference pixel sets, which reference pixel set to use, whether to apply reference pixel filtering, and which filter to use can be determined. If the associated information is explicitly specified, a flag may be generated. If the related information is defined implicitly, it can be determined according to the encoding information (the above-described state of the current block or the type <I/P/B> of the current image, the current image <Y/Cb/Cr>, etc., which may influence the internal prediction settings).

[00861] Although the present invention has been described with a focus on reference pixel set, reference pixel filtering, and reference pixel interpolation, other settings related to intra prediction may also be included. For example, in the prediction process, as before, according to the encoding information, it can also be determined that a prediction block is generated using (extrapolated, averaged and interpolated) reference pixels in accordance with the prediction mode, or to generate a prediction block, etc. d. different reference pixels are used than the reference pixels used in accordance with the existing directionality (for example, in order to correct the corresponding prediction pixels according to the position of the prediction pixel, a correction value is generated by additionally using other reference pixels, and then added to the existing prediction value, etc. .d.), etc. In this case, if the related information is defined explicitly, it can also be known by the related information about the prediction method used, otherwise, in the case of implicitly defining the related information, which prediction method to use can be determined by the state of the current block or the like. .P.

[00862] At the decoder, the associated description may be obtained in reverse order of the contents of the encoder. In the case of an explicit part, the associated information is analyzed. In the case of an implicit part, the related information is determined according to the encoding information, etc.

[00863] In the above description, the reference pixel filtering setting and the reference pixel interpolation setting can be determined taking into account the setting change contents with the number of reference pixel sets used in the present description.

INDUSTRIAL APPLICABILITY

[00864] The present invention can be applied to encoding/decoding an image signal.

Claims (70)

1. An intra prediction method applied to a decoding device, including: obtaining the intra prediction mode of the current block; determining a pixel line for intra prediction of the current block among the plurality of pixel lines; And performing intra prediction of the current block based on the intra prediction mode and the determined pixel line, receiving includes obtaining an intra prediction mode based on a predetermined default mode or a group of most probable modes (MPM) candidates; the method additionally includes: configuring the modes obtained from the mode included in the MPM candidate group as a MPM candidate group; And determining an order of prediction modes included in the MPM candidate group based on priority, wherein the priority is determined according to the order of preset prediction modes and modes derived from prediction modes initially included in the MPM candidate group. 2. The internal prediction method according to claim 1, characterized in that the resulting modes are represented as modes that have a difference a between mode intervals from the on mode, where a is a non-zero integer. 3. The internal prediction method according to claim 1, characterized in that predefined prediction modes are included in the group of MRM candidates in the order of direct current (DC) mode, flat mode, vertical mode and horizontal mode. 4. The internal prediction method according to claim 1, characterized in that the pixel line is a line of reference pixels, and the pixel line is determined based on the size and shape of the current block. 5. The internal prediction method according to claim 1, characterized in that it additionally includes performing filtering on the first reference pixel of the specified line of pixels. 6. The internal prediction method according to claim 5, characterized in that filtering is performed selectively based on a first flag indicating whether the first reference pixel is filtered for intra prediction. 7. The internal prediction method according to claim 6, characterized in that the first flag is obtained from the decoding device based on the encoding parameter of the current block, and the encoding parameter includes at least one of a block size, a color component type, an intra prediction mode, or whether intra prediction is applied to subblock elements. 8. The internal prediction method according to any one of claims. 1–7, characterized in that internal prediction is performed on the subblock elements of the current block and the subblocks are determined based on at least one of a flag indicating whether division should be performed, information about the direction of division, or information about the number of divisions. 9. An intra prediction method applied to an encoding device, including: obtaining the intra prediction mode of the current block; determining a pixel line for intra prediction of the current block among the plurality of pixel lines; And performing intra prediction of the current block based on the intra prediction mode and the determined pixel line, receiving includes obtaining an intra prediction mode based on a predetermined default mode or a group of most probable modes (MPM) candidates; the method additionally includes: configuring the modes obtained from the mode included in the MPM candidate group as a MPM candidate group; And determining an order of prediction modes included in the MPM candidate group based on priority, wherein the priority is determined according to the order of preset prediction modes and modes derived from prediction modes initially included in the MPM candidate group. 10. The internal prediction method according to claim 9, characterized in that the resulting modes are represented as modes that have a difference a between mode intervals from the on mode, where a is a non-zero integer. 11. The internal prediction method according to claim 9, characterized in that predefined prediction modes are included in the group of MRM candidates in the order of direct current (DC) mode, flat mode, vertical mode and horizontal mode. 12. The internal prediction method according to claim 9, characterized in that the pixel line is a line of reference pixels, and the pixel line is determined based on the size and shape of the current block. 13. The internal prediction method according to claim 9, characterized in that it additionally includes performing filtering on the first reference pixel of the specified line of pixels. 14. The internal prediction method according to claim 13, characterized in that filtering is performed selectively based on a first flag indicating whether the first reference pixel is filtered for intra prediction. 15. The internal prediction method according to claim 14, characterized in that it additionally includes encoding the first flag based on the encoding parameter of the current block and including it in the bitstream, and the encoding parameter includes at least one of a block size, a color component type, an intra prediction mode, or whether intra prediction is applied to subblock elements. 16. The internal prediction method according to any one of claims. 9–15, characterized in that internal prediction is performed on the subblock elements of the current block and the subblocks are determined based on at least one of a flag indicating whether division should be performed, information about the direction of division, or information about the number of divisions. 17. A decoding device comprising: a prediction mode decoding section configured to obtain an intra prediction mode of the current block; a reference pixel configuring section configured to determine a pixel line for intra prediction of the current block among the plurality of pixel lines; And a prediction block generating section configured to perform intra prediction of the current block based on the intra prediction mode and the determined pixel line, wherein the prediction mode decoding section is further configured to obtain an intra prediction mode based on a predetermined default mode or a group of candidate MPMs; And wherein the prediction mode decoding section is additionally configured to: configuring modes derived from a mode included in the MPM candidate group as a MPM candidate group; And determining an order of prediction modes included in the MPM candidate group based on priority, wherein the priority is determined according to the order of the preset prediction modes and modes derived from the prediction modes initially included in the MPM candidate group. 18. An encoding device containing: a prediction mode determining section configured to obtain an intra prediction mode of the current block; a reference pixel configuring section configured to determine a pixel line for intra prediction of the current block among the plurality of pixel lines; And a prediction block generating section configured to perform intra prediction of the current block based on the intra prediction mode and the determined pixel line, wherein the prediction mode determining section is further configured to obtain an intra prediction mode based on a predetermined default mode or a group of candidate MPMs; And wherein the section for determining the prediction mode is additionally configured to: configuring modes derived from a mode included in the MPM candidate group as a MPM candidate group; And determining an order of prediction modes included in the MPM candidate group based on priority, wherein the priority is determined according to the order of the preset prediction modes and modes derived from the prediction modes initially included in the MPM candidate group. 19. A computing device comprising a storage device and a program, wherein the storage device is configured to store a program executed by the processor; And the processor is configured to implement, when executing the program, the internal prediction method according to any one of claims. 1–8 or the internal prediction method according to any one of paragraphs. 9–16. 20. A computer storage medium on which a program is stored, which, when executed, implements the internal prediction method according to any one of claims. 1–8 or the internal prediction method according to any one of paragraphs. 9–16.