RU2809324C2 - Method and device for encoding and decoding video signals - Google Patents

Abstract

FIELD: video signal encoding and decoding.

SUBSTANCE: image decoding method according to the present invention includes the following steps: determining whether a merge offset vector encoding method can be applied to the current block; generating a list of merge candidates for the current block; indicating a merge candidate for the current block based on the list of merge candidates; and deriving a motion vector for the current block based on the merge candidate.

EFFECT: refinement of the motion vector.

18 cl, 38 dwg, 11 tbl

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

[0001] The present invention relates to a method and apparatus for encoding and decoding video signals.

PREREQUISITES FOR CREATION OF THE INVENTION

[0002] As display panels become larger, more and higher quality video services are required. The biggest challenge of high-definition video services is the significant increase in data volume, and to address this issue, research is being actively conducted to improve video compression rates. As an illustrative example, the Motion Picture Experts Group (MPEG) and the Video Coding Experts Group (VCEG) within the telecommunications standards sector of the International Telecommunication Union (ITU-T) formed the Joint Video Coding Team (JCT-VC) in 2009. JCT-VC proposed High Efficiency Video Coding (HEVC), which is a video compression standard that has a compression efficiency approximately twice that of H.264/AVC, and it was approved as a standard on January 25, 2013. With the rapid development of high-definition video services The effectiveness of HEVC is gradually revealing its limitations.

SUMMARY OF THE INVENTION

[0003] An object of the present invention is to provide a method for refining a motion vector obtained from a fusion candidate based on an offset vector when encoding/decoding a video signal and an apparatus for executing the method.

[0004] Another object of the present invention is to provide a method for transmitting an offset vector when encoding/decoding a video signal and an apparatus for performing the method.

[0005] The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and unmentioned other objects can be clearly understood by those skilled in the art from the following description.

[0006] A video signal decoding/encoding method according to the present invention includes the following steps: determining whether a merging motion vector difference encoding method is applied to the current block; generating a list of merge candidates for the current block; indicating a merge candidate for the current block based on the list of merge candidates; and obtaining a motion vector for the current block based on the merge candidate. In this case, when the merge motion vector difference encoding method is applied to the current block, the motion vector of the current block is obtained by adding an offset vector to the motion vector of the merge candidate when the maximum number of merge candidates that the merge candidate list can contain is multiple , the merge candidate of the current block is selected based on the index information decoded from the bitstream indicating any of the merge candidates, and when the maximum number is 1, the merge candidate is determined without decoding the index information.

[0007] In the video signal encoding and decoding method of the present invention, a displacement vector magnitude can be determined based on the first index information indicating any of the motion module candidates.

[0008] In the method of encoding and decoding video signals according to the present invention, at least one of the maximum value and minimum value of the motion module candidates may be set differently according to the value of a flag indicating the numerical values of the motion module candidates.

[0009] In the method for encoding and decoding video signals according to the present invention, the flag may be transmitted at the image level.

[0010] In the method of encoding and decoding video signals according to the present invention, at least one of the maximum value and minimum value of motion module candidates can be set differently according to the accuracy of the motion vector for the current block.

[0011] In the video signal encoding and decoding method of the present invention, the displacement vector modulus can be obtained by applying a shift operation to the value indicated by the motion modulus candidate indicated by the first index information.

[0012] In the method of encoding and decoding video signals according to the present invention, the direction of the offset vector can be determined based on the second index information indicating any of the vector direction candidates.

[0013] The features summarized above in relation to the present invention are merely illustrative aspects of the detailed description of the present invention, which will be described below, and do not limit the scope of the present invention.

[0014] According to the present invention, the efficiency of prediction performed between images can be improved by refining the motion vector of a fusion candidate based on the displacement vector.

[0015] According to the present invention, the efficiency of prediction performed between images can be improved by adaptively determining the magnitude and direction of the displacement vector.

[0016] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

BRIEF DESCRIPTION OF GRAPHIC MATERIALS

[0017] In FIG. 1 is a block diagram showing a video encoder according to one embodiment of the present invention.

[0018] In FIG. 2 is a block diagram showing a video decoder according to one embodiment of the present invention.

[0019] In FIG. 3 is a view showing a code tree base element according to one embodiment of the present invention.

[0020] In FIG. 4 is a view showing various types of partitioning of a coding block.

[0021] In FIG. 5 is a view showing a code tree element partitioning diagram.

[0022] In FIG. 6 is a view showing shapes of basic data items.

[0023] In FIG. 7 and 8 are views showing examples of dividing a coding block into a plurality of sub-blocks.

[0024] In FIG. 9 is a flowchart illustrating an inter-image prediction method according to one embodiment of the present invention.

[0025] In FIG. 10 is a view showing non-linear movements of an object.

[0026] In FIG. 11 is a flowchart illustrating a method for inter-image prediction based on affine motion according to one embodiment of the present invention.

[0027] In FIG. 12 is a view showing an example of affine source vectors of each affine motion model.

[0028] In FIG. 13 is a view showing an example of sub-block affine vectors in a 4-parameter motion model.

[0029] In FIG. 14 is a flowchart showing the process of obtaining movement information of the current block using the merging mode.

[0030] In FIG. 15 is a view showing an example of candidate blocks used to obtain a merge candidate.

[0031] In FIG. 16 is a view showing positions of reference samples.

[0032] In FIG. 17 is a view showing an example of candidate blocks used to obtain a merge candidate.

[0033] In FIG. 18 is a view showing an example in which the position of the reference count is changed.

[0034] In FIG. 19 is a view showing an example in which the position of the reference count is changed.

[0035] In FIG. 20 is a flowchart showing the process of updating the inter-section traffic information list.

[0036] In FIG. 21 is a view showing an embodiment of updating a cross-site merge candidate list.

[0037] In FIG. 22 is a view showing an example in which the index of a previously stored inter-site merge candidate is updated.

[0038] In FIG. 23 is a view showing the position of an illustrative sub-block.

[0039] In FIG. 24 is a view showing an example in which a list of inter-section motion information is generated for each inter-image prediction mode.

[0040] In FIG. 25 is a view showing an example in which a cross-section merging candidate included in the long-term traffic information list is added to the merging candidate list.

[0041] In FIG. 26 is a view showing an example in which redundancy checking is performed on only some of the merge candidates.

[0042] In FIG. 27 is a view showing an example in which the redundancy check is skipped for a particular merge candidate.

[0043] In FIG. 28 is a view showing a displacement vector according to the values of distance_idx indicating the magnitude of the displacement vector and direction_idx indicating the direction of the displacement vector.

[0044] In FIG. 29 is a view showing a displacement vector according to the values of distance_idx indicating the magnitude of the displacement vector and direction_idx indicating the direction of the displacement vector.

[0045] In FIG. 30 is a view showing partitioning patterns of a coding block when applying the triangular partitioning method.

[0046] In FIG. 31 is a view showing an example in which the offset vectors of each of the sub-elements are set differently.

[0047] In FIG. 32 is a view showing motion vector candidates that the refined merge candidate can take.

[0048] In FIG. 33 is a view showing a configuration of an offset list with merge refinement.

[0049] In FIG. 34 and 35 are views showing displacement vectors indicated by merging displacement candidates.

[0050] In FIG. 36 is a view showing candidate blocks used for obtaining motion vector prediction candidates.

[0051] In FIG. 37 is a view showing motion vector candidates that can be set as a refined motion vector prediction candidate.

[0052] In FIG. 38 is a view showing a configuration of an offset list with prediction vector refinement.

DETAILED DESCRIPTION

[0053] An embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0054] Video encoding and decoding is performed by a block element. For example, an encoding/decoding process such as transform, quantization, prediction, in-loop filtering, reconstruction, and the like may be performed on an encoding block, a transform block, or a prediction block.

[0055] Hereinafter, the block to be encoded/decoded will be referred to as the “current block”. For example, the current block may represent an encoding block, a transform block, or a prediction block according to the current stage of the encoding/decoding process.

[0056] In addition, it should be understood that the term “element” as used herein denotes a basic element for performing a particular encoding/decoding process, and the term “block” indicates an array of samples of a predetermined size. Unless otherwise specified, "block" and "element" may be used with the same meaning. For example, in the embodiment described below, it should be understood that a coding block and a coding element have the same meaning.

[0057] In FIG. 1 is a block diagram showing a video encoder according to one embodiment of the present invention.

[0058] Referring to FIG. 1, the video encoding apparatus 100 may include an image partitioning portion 110, prediction portions 120 and 125, transform portion 130, quantization portion 135, permutation portion 160, entropy encoding portion 165, inverse quantization portion 140, 145 for deconversion, part 150 for filtering and storage device 155.

[0059] Each of the components shown in FIG. 1 is shown independently to represent characteristic functions different from each other in a video encoding apparatus, but this does not mean that each component is constituted by a configuration item of a separate hardware or a single software. That is, each component is listed as a component for convenience of explanation, and at least two of the components may be combined to form a single component, or one component may be divided into multiple components to perform a function. Combination embodiments and component separation embodiments are also included within the scope of the present invention as long as they do not depart from the spirit of the present invention.

[0060] In addition, some of the components are not essential components that perform essential functions in the present invention, but may be optional components only to improve efficiency. The present invention can be implemented by including only the components necessary to implement the essence of the present invention, excluding components used to improve efficiency, and a structure containing only the necessary components, excluding optional components used to increase efficiency, is also included within the scope of the present invention .

[0061] The image partitioning portion 110 may partition the input image into at least one processing element. In this case, the processing element may be a prediction element (PU), a transformation element (TU), or a coding element (CU). The image partitioning portion 110 may partition an image into a plurality of encoding elements, prediction elements, and transform elements, and encode the image by selecting a plurality of encoding element, prediction element, and transform element based on a predetermined criterion (eg, a cost function).

[0062] For example, one image may be divided into multiple encoding elements. A recursive tree structure, such as a quaternary tree structure, may be used to partition the encoding elements in an image. A video or encoding element split into different encoding elements using the largest encoding element as the root can be split to have as many child nodes as there are split encoding elements. An encoding element that is no longer split according to a predefined constraint becomes a leaf node. That is, if it is assumed that only a square partition is possible for one encoding element, one encoding element can be split into at most four different encoding elements.

[0063] Further, in an embodiment of the present invention, an encoding element may be used in the value of an element performing encoding or in the value of an element performing decoding.

[0064] The prediction element may be an element laid out in the shape of at least one square, rectangle, or the like. the same size within a single encoding element, or it may be any prediction element of the prediction elements partitioned within a single encoding element that is partitioned to have a different shape and/or size from those of another prediction element.

[0065] If the encoding element is not the smallest encoding element, when a prediction element that performs intra prediction based on the encoding element is generated, intra prediction can be performed without dividing the image into a plurality of N×N prediction elements.

[0066] The prediction portions 120 and 125 may include an inter-picture prediction portion 120 that performs inter-picture prediction and an intra prediction portion 125 that performs intra prediction. It can be determined whether to use inter-picture prediction or perform intra prediction on a prediction element, and determine specific information (eg, intra prediction mode, motion vector, reference image, etc.) according to each prediction method. In this case, the processing element for performing the prediction may be different from the processing element for determining the prediction method and the specific content. For example, a prediction method and a prediction mode may be determined in a prediction element, and prediction may be performed in a transform element. A residual coefficient (residual block) between the reconstructed prediction block and the original block may be input to the transformation portion 130. In addition, prediction mode information, motion vector information, and the like used for prediction can be encoded by the entropy encoding portion 165 together with a residual coefficient and transmitted to the decoder. When a particular encoding mode is used, the original block can be encoded as is and transmitted to the decoder without generating a prediction block by the prediction portions 120 and 125.

[0067] The inter-picture prediction portion 120 may predict a prediction element based on information about at least one image of the images before or after the current image, and in some cases, it may predict a prediction element based on partial region information. which was encoded in the current image. The inter-image prediction portion 120 may include a reference image interpolation portion, a motion prediction portion, and a motion compensation portion.

[0068] The reference image interpolation portion may receive reference image information from the storage device 155 and generate pixel information for an integer number of pixels or less from the reference image. In the case of a luminance pixel, an 8-tap DCT-based interpolation filter with a variable filter coefficient can be used to generate pixel information of an integer number of pixels or less through a 1/4 pixel element. In the case of a chroma signal, a 4-tap DCT-based interpolation filter with a variable filter coefficient can be used to generate pixel information of an integer number of pixels or less through a 1/8 pixel element.

[0069] The motion prediction portion may perform motion prediction based on a reference image interpolated by the reference image interpolation portion. Various methods such as Full Search Based Block Matching Algorithm (FBMA), Three Stage Search (TSS), New Three Stage Search (NTS) algorithm, and the like can be used as the motion vector calculation method. The motion vector may have a motion vector value as a 1/2 or 1/4 pixel element based on the interpolated pixels. The motion prediction portion may predict the current prediction element by changing the motion prediction mode. Various methods such as skip mode, merge mode, advanced motion vector prediction (AMVP) mode, intra-block copy mode, etc. can be used as the motion prediction mode.

[0070] The intra prediction portion 125 may generate a prediction element based on information about reference pixels located in the vicinity of the current block, which is information about a pixel in the current image. When a block adjacent to the current prediction element is a block on which inter-picture prediction has been performed, and thus the reference pixel is a pixel on which inter-picture prediction has been performed, the reference pixel is included in a block that has been subject to inter-picture prediction may be used in place of the reference pixel information of a nearby block that has been intra-predicted. That is, when a reference pixel is not available, at least one reference pixel among the available reference pixels may be used instead of the unavailable reference pixel information.

[0071] In intra prediction, a prediction mode may include a prediction mode based on angle information, which uses reference pixel information according to the prediction direction, and a non-angle information based prediction mode, which does not use direction information when executing predictions. The mode for predicting luminance information may be different from the mode for predicting chrominance information, and the intra prediction mode information used to predict luminance information or information about a predicted luminance signal may be used to predict chrominance information.

[0072] If the size of the prediction element is the same as the size of the transform element when intra prediction is performed, intra prediction may be performed on the prediction element based on the pixel on the left side, the pixel on the upper left side, and the pixel on top of the prediction element. However, if the size of the prediction element is different from the size of the transformation element when intra prediction is performed, intra prediction may be performed using a reference pixel based on the transformation element. In addition, intra prediction using N×N partitioning can only be used for the smallest coding element.

[0073] By the intra prediction method, a prediction block can be generated after applying an adaptive intra smoothing (AIS) filter to a reference pixel according to the prediction mode. The type of AIS filter applied to the reference pixel can vary. To perform the intra prediction method, the intra prediction mode of the current prediction element can be predicted from the intra prediction mode of the prediction element existing in the vicinity of the current prediction element. When the prediction mode of the current prediction element is predicted using mode information predicted from a neighboring prediction element, if the intra prediction modes of the current prediction element are the same as the nearby prediction element, then information indicating that the prediction modes of the current prediction element are the same as the element nearby prediction element can be transmitted using the predetermined flag information, and if the prediction modes of the current prediction element and the nearby prediction element are different from each other, the prediction mode information of the current block can be encoded by performing entropy encoding.

[0074] In addition, a residual block may be generated containing a prediction element that has performed prediction based on the prediction element generated by the prediction portions 120 and 125 and residual coefficient information that is the difference value of the prediction element from the original block. The generated residual block may be input to the conversion portion 130.

[0075] The transformation portion 130 may transform a residual block containing the original block and information about the residual coefficient of the prediction element generated by the prediction portions 120 and 125 using a transformation method such as discrete cosine transform (DCT) or discrete sine transform ( DST). In this case, the DCT transform base contains at least one of DCT2 or DCT8, and the DST transform base contains DST7. Whether or not to apply DCT or DST to transform the residual block can be determined based on information about the intra prediction mode of the prediction element used to generate the residual block. The transformation regarding the remainder block may be skipped. A flag may be encoded indicating whether or not to skip the conversion with respect to the remainder block. Skip conversion may be allowed for a residual block having a size that is less than or equal to the threshold, luma component, or chrominance component in a 4:4:4 format.

[0076] The quantization portion 135 may quantize the values converted to the frequency domain by the conversion portion 130. Quantization factors may vary depending on the block or importance of the video. The value calculated by the quantization portion 135 may be provided to the inverse quantization portion 140 and the permutation portion 160.

[0077] The permutation portion 160 may perform permutation of coefficient values for the quantized residual coefficients.

[0078] The permutation portion 160 may change the coefficients of a two-dimensional block shape to a one-dimensional vector shape through a coefficient scanning method. For example, the permutation portion 160 may scan from the DC coefficients to the high frequency domain coefficients using a zigzag scanning method and change the coefficients into a one-dimensional vector form. According to the size of the transform element and the intra prediction mode, instead of zigzag scanning, vertical scanning in the form of scanning of two-dimensional block shape coefficients in the column direction and horizontal scanning of two-dimensional block shape coefficients in the row direction can be used. That is, according to the transform element size and the intra prediction mode, the scanning method to be used from zigzag scanning, vertical direction scanning, and horizontal direction scanning can be determined.

[0079] The entropy encoding portion 165 may perform entropy encoding based on the values calculated by the permutation portion 160. For entropy coding, various encoding methods can be used, such as exponential Golomb coding, context-adaptive variable-length coding (CAVLC), context-adaptive binary arithmetic coding (CABAC), and the like.

[0080] The entropy encoding portion 165 may encode various information such as residual coefficient information and coding element block type information, prediction mode information, split element information, prediction element information and transmission element information, vector information motion, reference frame information, block interpolation information, and filtering information that is input from the permutation portion 160 and the prediction portions 120 and 125.

[0081] The entropy encoding portion 165 may perform entropy encoding of the coefficient value of the encoding element input from the permutation portion 160.

[0082] The inverse quantization portion 140 and the inverse transform portion 145 perform inverse quantization of the values quantized by the quantization portion 135 and inverse transform of the values transformed by the transform portion 130. The residual coefficient generated by the inverse quantization portion 140 and the inverse transform portion 145 may be combined with a prediction element predicted by the motion estimation portion, the motion compensation portion, and the intra prediction portion included in the prediction portions 120 and 125 to generating a recovered block.

[0083] The filtering portion 150 may comprise at least one of a deblocking filter, an offset correction element, and an adaptive loop filter (ALF).

[0084] A deblocking filter may remove block distortion generated at a boundary between blocks in a reconstructed image. Determining whether to deblock or apply a deblocking filter to the current block can be made based on the pixels contained in multiple columns or rows contained in the block. A strong filter or a weak filter can be applied according to the required degree of filtering to remove blocking when applying a deblocking filter to a block. In addition, when vertical direction filtering and horizontal direction filtering are performed when using a deblocking filter, vertical direction filtering and horizontal direction filtering can be performed in parallel.

[0085] The offset correction element may correct the offset of the original video by a pixel element for the image that has been deblocked. To perform offset correction for a particular image, you can use a method of dividing the pixels included in the video into a certain number of regions, defining an area to perform the offset and applying the offset to the area, or a method of applying the offset that takes into account the edge information of each pixel.

[0086] Adaptive loop filtering (ALF) can be performed based on the value obtained by comparing the reconstructed and filtered video with the original video. After dividing the pixels included in the image into predefined groups, a single filter can be defined to be applied to the corresponding group, and filtering can be performed differently for each group. A luminance signal, which is information related to whether to apply ALF, may be transmitted for each coding unit (CU), and the shape and filter coefficient of the ALF filter to be applied may vary depending on each block. In addition, an ALF filter of the same type (fixed type) can be applied regardless of the characteristic of the block used.

[0087] The storage device 155 may store the reconstructed block or image calculated by the filtering portion 150, and the reconstructed and stored block or image may be provided to the prediction portions 120 and 125 when performing inter-image prediction.

[0088] In FIG. 2 is a block diagram showing a video decoder according to one embodiment of the present invention.

[0089] Referring to FIG. 2, video decoder 200 may include an entropy decoding portion 210, a permutation portion 215, an inverse quantization portion 220, an inverse transform portion 225, prediction portions 230 and 235, a filtering portion 240, and a memory 245.

[0090] When a video bitstream is input from a video encoder, the input bitstream can be decoded according to a procedure opposite to that of the video encoder.

[0091] The entropy decoding portion 210 may perform entropy decoding according to a procedure opposite to the procedure of performing entropy encoding in the entropy decoding portion of the video encoder. For example, various methods corresponding to the method performed by the video encoder may be used, such as exponential Golomb coding, context adaptive variable length coding (CAVLC), and context adaptive binary arithmetic coding (CABAC).

[0092] The entropy decoding portion 210 may decode information associated with intra-prediction and inter-picture prediction performed by the encoder.

[0093] The permutation portion 215 may perform permutation on the bitstream subjected to entropy decoding by the entropy decoding portion 210 based on the permutation method performed by the encoder. Coefficients expressed in one-dimensional vector form can be recovered and rearranged as coefficients in two-dimensional block form. The permutation portion 215 may receive information related to coefficient scanning performed by the encoding portion and perform reconstruction by an inverse scan method based on the scanning order performed by the corresponding encoding portion.

[0094] The inverse quantization portion 220 may perform inverse quantization based on the quantization parameter provided by the encoder and the permuted block coefficient value.

[0095] The inverse transform portion 225 may perform an inverse transform on the transform element, i.e. DCT or DST performed by the conversion part with respect to the quantization result performed by the video encoder, i.e. reverse DCT or reverse DST. In this case, the DCT transform base may comprise at least one of DCT2 and DCT8, and the DST transform base may comprise DST7. Alternatively, when conversion is skipped in the video encoder, the de-conversion portion 225 may also skip the de-conversion. The inverse conversion may be performed based on the transfer element determined by the video encoder. The video decoder deconversion portion 225 may selectively perform a conversion method (eg, DCT or DST) according to a plurality of pieces of information such as a prediction method, a current block size, a prediction direction, and the like.

[0096] The prediction parts 230 and 235 may generate a prediction block based on the prediction block generation-related information provided by the entropy decoder 210 and the previously decoded block or image information provided by the storage device 245.

[0097] As described above, if the size of the prediction element and the size of the transform element are the same, when intra prediction is performed in the same way as the operation in a video encoder, intra prediction is performed on the prediction element based on the pixel located on the left side, the pixel on the upper left side side and a pixel above the prediction element. However, if the size of the prediction element and the size of the transformation element are different from each other when intra prediction is performed, intra prediction may be performed using a reference pixel based on the transformation element. In addition, intra prediction using N×N partitioning can only be used for the smallest coding element.

[0098] The prediction portions 230 and 235 may include a prediction element determination portion, an inter-picture prediction portion, and an intra prediction portion. The prediction element determining portion may receive various information such as prediction element information input from the entropy decoding portion 210, prediction mode information of an intra prediction method, information related to motion prediction of an inter-picture prediction method, and the like. . Then, the prediction element determining part may identify the prediction element from the current encoding element and determine whether the prediction element performs inter-picture prediction or intra prediction. The inter-picture prediction portion 230 may perform inter-picture prediction regarding the current prediction element based on information included in at least one image of the images before or after the current image, including the current prediction element, by using the information , necessary for inter-picture prediction of the current prediction element provided by the video encoder. Alternatively, the inter-image prediction portion 230 may perform inter-image prediction based on the partial region information previously reconstructed in the current image containing the current prediction element.

[0099] To perform prediction performed between pictures, it can be determined based on the encoding element whether the motion prediction method of the prediction element included in the corresponding encoding element is a skip mode, a merge mode, an advanced motion vector prediction mode (AMVP mode), or a copy mode inside the block.

[00100] The intra prediction portion 235 may generate a prediction block based on information about a pixel in the current image. When the prediction element is a prediction element that has performed intra prediction, intra prediction may be performed based on the intra prediction mode information of the prediction element provided by the video encoder. The intra prediction portion 235 may include an adaptive intra-smoothing (AIS) filter, a reference pixel interpolation portion, and a DC filter. The AIS filter is a part that performs filtering on a reference pixel of the current block, and can determine whether to apply a filter according to the prediction mode of the current prediction element, and apply the filter. AIS filtering may be performed on a reference pixel of the current block by using the prediction mode and AIS filter information of the prediction element provided by the video encoder. When the prediction mode of the current block is a mode that does not perform AIS filtering, the AIS filter may not be applied.

[00101] When the prediction element prediction mode is a prediction element that performs intra prediction based on a pixel value obtained by interpolating a reference pixel, the reference pixel interpolation part may generate a reference pixel of an element composed of pixels that has an integer value or a value which is less than an integer value by interpolating the reference pixel. When the prediction mode of the current prediction element is a prediction mode that generates a prediction block without interpolating a reference pixel, the reference pixel may not be interpolated. The DC filter may generate a prediction block by filtering when the prediction mode of the current block is a DC mode.

[00102] The reconstructed block or image may be provided to part 240 for filtering. The filtering portion 240 may include a deblocking filter, an offset correction element, and an ALF.

[00103] Information about whether to apply a deblocking filter to the corresponding block or image, and information about whether to apply a strong filter or a weak filter when the deblocking filter is applied may be provided by the video encoder. The video decoder deblocking filter may be provided with information associated with the deblocking filter provided by the video encoder, and the video decoder may perform deblocking filtering on the corresponding block.

[00104] The offset correction element may perform offset correction on the reconstructed image based on the offset correction type and offset value information applied to the video when encoding is performed.

[00105] ALF may be applied to an encoding element based on information about whether or not ALF should be applied and information about ALF coefficients provided by the encoder. ALF information can be provided for inclusion in a set of specific parameters.

[00106] Storage device 245 may store the reconstructed image or block and use it as a reference image or reference block, and may provide the reconstructed image to an output element.

[00107] In FIG. 3 is a view showing a code tree base element according to one embodiment of the present invention.

[00108] A maximum size coding block may be specified as a code tree block. The image is divided into many code tree units (CTUs). A code tree element is a coding element having a maximum size and may be called a large coding unit (LCU). In fig. Figure 3 shows an example in which an image is divided into many code tree elements.

[00109] The code tree element size can be set at the image level or the sequence level. To do this, information indicating the size of the code tree element may be transmitted by an image parameter set or a sequence parameter set.

[00110] For example, the code tree element size for the entire image in the sequence may be set to 128×128. Alternatively, at the image level, any size between 128×128 and 256×256 may be defined as the code tree element size. For example, the code tree element size may be set to 128×128 in the first image, and the code tree element size may be set to 256×256 in the second image.

[00111] Coding blocks can be generated by splitting a code tree element. The encoding block specifies a base element for performing encoding/decoding. For example, prediction or transformation may be performed for each encoding block, or a predictive encoding mode may be determined for each encoding block. Here, the predictive encoding mode indicates a method for generating a prediction image. For example, the predictive coding mode may include intra-picture prediction (intra-picture prediction), inter-picture prediction (inter-picture prediction), current picture reference (CPR), or intra-block copy (IBC), or combined prediction. For a coding block, a prediction block may be generated by using at least one predictive coding mode of intra prediction, inter-picture prediction, anchor to current picture, and combined prediction.

[00112] Information indicating a predictive encoding mode of the current block may be transmitted via a bitstream. For example, the information may be a 1-bit flag indicating whether the predictive coding mode is an intra-picture mode or an inter-picture mode. Only when the predictive encoding mode of the current block is determined to be an inter-picture mode can lock to the current picture or combined prediction be used.

[00113] Linking to the current picture is for establishing the current picture as a reference picture and obtaining a prediction block of the current block from a region that has already been encoded/decoded in the current picture. In this case, the current image means the image containing the current block. Information indicating whether the current block is snapped to the current image may be conveyed via a bitstream. For example, the information may be a 1-bit flag. When the flag is true, the predictive encoding mode of the current block can be defined as being tied to the current picture, and when the flag is false, the predictive mode of the current block can be defined as inter-picture prediction.

[00114] Alternatively, the predictive coding mode of the current block may be determined based on the index of the reference picture. For example, when the reference picture index indicates the current picture, the predictive encoding mode of the current block may be determined to be anchored to the current picture. When the reference picture index indicates a picture different from the current picture, the predictive coding mode of the current block can be defined as prediction performed between pictures. That is, anchoring to the current image is a prediction method using information about the region in which encoding/decoding has been performed in the current image, and prediction performed between images is a prediction method using information about another image in which encoding/decoding has been performed. encoding/decoding.

[00115] Combined prediction represents a coding mode in which two or more of intra-prediction, inter-picture prediction, and current-picture anchoring are combined. For example, when using combined prediction, a first prediction block may be generated based on one of intra-prediction, inter-image prediction, and current image anchoring, and a second prediction block may be generated based on the other. When generating the first prediction block and the second prediction block, the final prediction block may be generated by an averaging operation or a weighted addition operation of the first prediction block and the second prediction block. Information indicating whether combined prediction is applied may be transmitted via a bitstream. The information may be a 1-bit flag.

[00116] In FIG. 4 is a view showing various types of partitioning of a coding block.

[00117] An encoding block may be partitioned into a plurality of encoding blocks based on a quaternary tree partition, a binary tree partition, or a ternary tree partition. The split encoding block may be split again into a plurality of encoding blocks based on a quaternary tree split, a binary tree split, or a ternary tree split.

[00118] Quaternary tree partitioning refers to a partitioning method that splits the current block into four blocks. As a result of quaternary tree partitioning, the current block can be split into four square-shaped partitions (see “SPLIT_QT” in Fig. 4(a)).

[00119] Binary tree partitioning refers to a partitioning method that splits the current block into two blocks. Splitting the current block into two blocks along the vertical direction (i.e. using a vertical line intersecting the current block) can be called binary tree splitting in the vertical direction, and splitting the current block into two blocks along the horizontal direction (i.e. with using a horizontal line intersecting the current block) can be called a binary tree partition in the horizontal direction. Binary tree partitioning can split the current block into two non-square partitions. "SPLIT_BT_VER" in Fig. 4(b) represents the result of binary tree splitting in the vertical direction, and “SPLIT_BT_HOR” in FIG. 4(c) presents the result of binary tree partitioning in the horizontal direction.

[00120] Ternary tree partitioning refers to a partitioning method that partitions the current block into three blocks. Splitting the current block into three blocks along the vertical direction (i.e. using two vertical lines crossing the current block) can be called ternary tree splitting in the vertical direction, and splitting the current block into three blocks along the horizontal direction (i.e. using two horizontal lines crossing the current block) can be called ternary tree partitioning in the horizontal direction. As a result of ternary tree partitioning, the current block can be split into three non-square partitions. In this case, the width/height of the section located in the center of the current block can be twice the width/height of other sections. "SPLIT_TT_VER" in Fig. 4(d) represents the result of ternary tree partitioning in the vertical direction, and “SPLIT_TT_HOR” in FIG. 4(e) presents the result of ternary tree partitioning in the horizontal direction.

[00121] The number of splits of a code tree element can be set as a split depth. The maximum split depth of a code tree element can be determined at the sequence level or the image level. Accordingly, the maximum depth of a code tree element may differ for each sequence or image.

[00122] Alternatively, the maximum partitioning depth for each partitioning method may be determined separately. For example, the maximum partition depth allowed for a quaternary tree partition may be different from the maximum partition depth allowed for a binary tree partition and/or ternary tree partition.

[00123] The encoder may transmit information indicating at least one of a split type and a split depth of the current block via a bitstream. The decoder may determine the split type and split depth of a code tree element based on information parsed from the bitstream.

[00124] In FIG. 5 is a view showing a code tree element partitioning diagram.

[00125] Partitioning a coding block using a partitioning method such as quaternary tree partitioning, binary tree partitioning, and/or ternary tree partitioning may be referred to as multi-tree partitioning.

[00126] Coding blocks generated by applying a multi-tree partition to a coding block may be referred to as lower coding blocks. When the partition depth of the encoding block is k, the partition depth of the lower encoding blocks is set to k+1.

[00127] Conversely, for coding blocks having a partition depth k+1, the encoding block having a partition depth k may be referred to as an upper encoding block.

[00128] The partition type of the current encoding block may be determined based on at least one of the partition type of the upper encoding block and the partition type of the adjacent encoding block. Here, a neighboring encoding block is an encoding block adjacent to the current encoding block, and may include at least one of an upper adjacent block and a left adjacent block of the current encoding block, and an adjacent block adjacent to the upper left corner. Here, the type of splitting may include at least one of the following: whether or not quaternary tree splitting was used, whether or not binary tree splitting was used, the direction of binary tree splitting, whether or not ternary tree splitting was used, and the direction of splitting based on a ternary tree.

[00129] To determine the type of splitting of the encoding block, information indicating whether the coding block can be split may be transmitted by a bit stream. The information is a 1-bit flag "split_cu_flag", and when the flag is true, it indicates that the encoding block is split using a multi-tree splitting method.

[00130] When split_cu_flag is true, information indicating whether a quaternary tree encoding block is split may be transmitted by the bitstream. The information is a 1-bit flag in the form split_qt_flag, and when the flag is true, the encoding block can be split into four blocks.

[00131] For example, in the example shown in FIG. 5, when a code tree element is partitioned based on the quaternary tree, four encoding blocks having a partition depth of 1 are generated. In addition, it is shown that the partition based on the quaternary tree is applied again to the first and fourth encoding blocks of the four encoding blocks generated by the partitioning based on a quaternary tree. As a result, four coding blocks having a partition depth of 2 can be generated.

[00132] In addition, coding blocks having a partition depth of 3 can be generated by repeatedly applying the quaternary tree partition to a coding block having a partition depth of 2.

[00133] When the quaternary tree partitioning is not applied to an encoding block, it can be determined whether a binary tree partitioning or a ternary tree partitioning is performed on the encoding block, taking into account at least one of the following: the size of the encoding block , whether the encoding block is located on the image boundary, the maximum partitioning depth, and the type of partitioning of the adjacent block. When it is determined that binary tree partitioning or ternary tree partitioning should be performed on an encoding block, information indicating the direction of partitioning may be transmitted by a bitstream. The information may be a 1-bit flag in the form mtt_split_cu_vertical_flag. Based on the flag, it can be determined whether the dividing direction is the vertical direction or the horizontal direction. Additionally, information indicating whether a binary tree partition or a ternary tree partition is applied to the encoding block may be transmitted by the bit stream. The information can be a 1-bit flag in the form mtt_split_cu_binary_flag. Based on the flag, it can be determined whether a binary tree partition or a ternary tree partition is applied to the encoding block.

[00134] For example, in the example shown in FIG. 5, it is shown that a binary tree partition in the vertical direction is applied to a coding block having a partition depth of 1, a ternary tree partition in the vertical direction is applied to the left encoding block of the encoding blocks generated by the partition, and a partition into the binary tree base in the vertical direction is applied to the right encoding block.

[00135] When implementing an apparatus for video encoding or decoding, there is a problem that a portion that is larger than a threshold value is difficult to process due to the characteristics of the hardware. For example, there is a problem that when it is possible to simultaneously process up to 4096 samples based on hardware characteristics, 64x64 data elements must be redundantly accessed and processed, and the data cannot be processed simultaneously in in the case of sections having samples in number greater than 4096. Similarly, the basic data processing element can be defined as a pipeline-based basic data element (virtual processing unit, VPDU, hereinafter referred to as the basic data element).

[00136] A basic data element may be classified as being of a square, non-square, or non-rectangular type.

[00137] In FIG. 6 is a view showing shapes of basic data items.

[00138] Basic data elements may contain a maximum number of samples or less than the maximum number of samples that can be processed simultaneously. For example, as shown in the example of FIG. 6(a), square blocks having a size of 64×64 can be set as basic data elements. Alternatively, non-square blocks can be set as base data elements. For example, as shown in the example of FIG. 6(b) or 6(c), a block having a size of 32x128 or a block having a size of 64x32 may be set as the base data element.

[00139] Although not shown, triangular, L-shaped, and polygonal data elements may be defined.

[00140] Information for defining a basic data element may be transmitted via a bit stream. The information may be for determining at least one of a size and a shape of the underlying data element. Based on the information, it can be determined whether or not to allow the non-square baseline data item, or whether to allow the non-rectangular baseline data item.

[00141] Alternatively, at least one of the size and shape of the base data element may be predefined in the encoder and decoder.

[00142] Whether or not to enable the partition type of the encoding block can be determined taking into account the size of the underlying data element. For example, when the encoding block generated by splitting the encoding block is larger than the base data element, the splitting may not be allowed. Alternatively, when the non-square encoding block generated by splitting the encoding block is larger than the base data element, the splitting may not be allowed. For example, when the width or height of an encoding block is greater than a threshold value, or when the number of samples included in an encoding block is greater than a threshold value, binary tree or ternary tree partitioning may not be allowed. Accordingly, encoding of information related to the binary tree or ternary tree partitioning may be skipped.

[00143] Alternatively, it may be set to be required to split an encoding block that is larger than the base data element. Alternatively, it may be specified to be required to perform binary tree partitioning or ternary tree partitioning on an encoding block that is larger than the base data element. Accordingly, for an encoding block that is larger than the base data element, although the split_flag indicating whether or not to split the encoding block is not encoded, the flag value can be obtained as 1.

[00144] As another example, an encoding block that is larger than a basic data element may be divided into a plurality of sub-blocks. Here, the subblock may be set as a prediction element, which is a base element for prediction, or a transformation element, which is a base element for transformation and/or quantization. In this case, the division of the encoding block into a plurality of prediction elements may be specified as the division of a VPDU prediction element, and the division of the encoding block into a plurality of transform elements may be specified as the division of a VPDU transform element.

[00145] At least one of a VPDU prediction element split and a VPDU transform element split may be applied to a coding block. The coding block splitting type according to the VPDU prediction element splitting application can be set to the same as the coding block splitting type according to the VPDU transform element splitting application.

[00146] When only VPDU prediction element partitioning is applied to a coding block, prediction is performed on a per-subblock basis, but transform and/or quantization may be performed on a coding block basis. In this case, a prediction mode such as a prediction encoding mode, an intra prediction mode, or an inter-picture prediction mode may be determined for the encoding block.

[00147] When only VPDU transform element partitioning is applied to a coding block, prediction is performed for the subblock, but transform and/or quantization may be performed for each subblock.

[00148] In FIG. 7 and 8 are views showing examples of dividing a coding block into a plurality of sub-blocks.

[00149] In FIG. 7 is a view showing a partitioning pattern when only a square datum is allowed, and FIG. 8 is a view showing a partitioning scheme when a base item and a non-square base item are allowed.

[00150] When it is assumed that only square datums are allowed, FIG. 7(a) and 7(b), CU0 and CU2 are defined as two different VPDUs, and CU1 is defined as four different VPDUs. Accordingly, CU0 and CU2 can be divided into two sub-blocks, and CU1 can be divided into four sub-blocks.

[00151] When it is assumed that square datums and non-square datums are allowed, FIG. 8(a) and 8(b), CU0 and CU2 can be defined as one VPDU, while CU1 can be defined using two different VPDUs. Accordingly, CU0 and CU2 are not divided into subblocks, while CU1 can be divided into two subblocks.

[00152] In this case, CU1 may be divided into square sub-blocks or non-square sub-blocks. For example, CU1 may be divided into two square subblocks based on a horizontal line that divides CU1 into an upper part and a lower part. Alternatively, CU1 may be partitioned into two non-square sub-blocks based on a vertical line that partitions CU1 into a left part and a right part.

[00153] When there are a plurality of partition type candidates applicable to a coding block, information indicating any of the plurality of partition type candidates may be transmitted by a bitstream. For example, the information may indicate whether the encoding block should be divided into square subblocks, or whether the encoding block should be divided into non-square subblocks.

[00154] Alternatively, dividing the encoding block into square subblocks may be set to have a priority that is higher than the priority of dividing the encoding block into non-square subblocks. For example, partitioning an encoding block into non-square sub-blocks may be permitted when partitioning an encoding block into square sub-blocks is not permitted.

[00155] Alternatively, the encoding block partition type may be determined based on the encoding block partition type of the parent node. For example, it may be set to partition the encoding block into square sub-blocks when the encoding block of the parent node is partitioned based on the ternary tree. On the other hand, it may be set to partition the encoding block into non-square sub-blocks when the encoding block of the parent node is partitioned based on a binary tree or a ternary tree.

[00156] Inter-picture prediction is a predictive coding mode that predicts the current block by using information about the previous picture. For example, a block at the same position as the current block in the previous image (hereinafter referred to as a compatible block) can be set as a prediction block of the current block. Hereinafter, a prediction block generated based on a block at the same position as the current block will be called a compatible prediction block.

[00157] On the other hand, when an object located in a previous image has moved to a different position in the current image, the current block can be efficiently predicted by using the movement of the object. For example, when the motion direction and size of an object can be learned by comparing a previous image and a current image, a prediction block (or prediction image) of the current block can be generated taking into account the motion information of the object. Hereinafter, the prediction block generated by using the motion information may be called a motion prediction block.

[00158] A residual block may be generated by subtracting a prediction block from a current block. In this case, when there is motion of the object, the energy of the residual block can be reduced by using a motion prediction block instead of a compatible prediction block, and thus the compression efficiency of the residual block can be improved.

[00159] As described above, generating a prediction block using motion information may be called motion-compensated prediction. In most inter-image predictions, a prediction block may be generated based on motion compensated prediction.

[00160] The motion information may comprise at least one of a motion vector, a reference image index, a prediction direction, and a bidirectional weight index. The motion vector represents the direction of motion and the size of the object. The reference picture index indicates the reference picture of the current block of the reference pictures included in the reference picture list. The prediction direction indicates any of unidirectional L0 prediction, unidirectional L1 prediction, and bidirectional prediction (L0 prediction and L1 prediction). According to the prediction direction of the current block, at least one of the movement information in the L0 direction and the movement information in the L1 direction may be used. The bidirectional weight index indicates the weighting value applied to the L0 prediction block and the weighting value applied to the L1 prediction block.

[00161] In FIG. 9 is a flowchart illustrating an inter-image prediction method according to one embodiment of the present invention.

[00162] Referring to FIG. 9, the inter-picture prediction method includes the steps of determining (S901) an inter-picture prediction mode of the current block, obtaining (S902) information about the movement of the current block according to the determined inter-picture prediction mode, and performing (S903) the inter-picture prediction motion compensation for the current block based on received motion information.

[00163] Here, the inter-picture prediction mode represents various methods for determining motion information of the current block, and may include an inter-picture prediction mode that uses translational motion information, and an inter-picture prediction mode that uses the information about affine motion. For example, an inter-image prediction mode that uses translational motion information may include a fusion mode and an advanced motion vector prediction mode, and an inter-image prediction mode that uses affine motion information may include an affine fusion mode and an advanced mode. affine motion vector predictions. The motion information of the current block may be determined based on a neighboring block adjacent to the current block or information analyzed from the bitstream according to an inter-picture prediction mode.

[00164] Next, an inter-image prediction method that uses affine motion information will be described in detail.

[00165] In FIG. 10 is a view showing non-linear movements of an object.

[00166] Nonlinear motion of an object can be generated in a video. For example, as shown in the example of FIG. 10, such nonlinear movement of the object as approaching, moving away, rotating, affine transformation, or the like can occur. cameras. When nonlinear motion of an object occurs, the motion of the object cannot be effectively expressed by a translational motion vector. Accordingly, encoding efficiency can be improved by using affine motion instead of translational motion in the region where nonlinear object motion occurs.

[00167] In FIG. 11 is a flowchart illustrating a method for inter-image prediction based on affine motion according to one embodiment of the present invention.

[00168] Whether the inter-picture prediction method based on affine motion is applied to the current block can be determined based on information analyzed from the bitstream. In particular, whether an inter-image prediction method based on affine motion is applied to the current block can be determined based on at least one of a flag indicating whether the affine fusion mode is applied to the current block and a flag indicating whether There is an improved mode for predicting the affine motion vector to the current block.

[00169] When the inter-image prediction method based on affine motion is applied to the current block, an affine motion model of the current block can be determined (S1101). The affine motion model may be defined as at least one of a six-parameter affine motion model and a four-parameter affine motion model. A six-parameter affine motion model expresses affine motion using six parameters, and a four-parameter affine motion model expresses affine motion using four parameters.

[00170] Equation 1 expresses affine motion using six parameters. Affine motion represents non-translational motion for a predefined region defined by affine source vectors.

[00171] Equation 1

[00172]

[00173]

[00174] When affine motion is expressed using six parameters, complex motion can be expressed. However, as the number of bits required to encode each parameter increases, the encoding efficiency may decrease. Accordingly, affine motion can be expressed using four parameters. Equation 2 expresses the affine motion using four parameters.

[00175] Equation 2

[00176]

[00177]

[00178] Information for determining the affine motion model of the current block may be encoded and transmitted via a bitstream. For example, the information could be a 1-bit flag in the form "affine_type_flag". When the flag value is 0, it may indicate that a 4-parameter affine motion model is applied, and when the flag value is 1, it may indicate that a 6-parameter affine motion model is applied. The flag may be encoded through a slice, tile, or block element (eg, through an encoding block or encoding tree element). When a flag is passed at the slice level, the affine motion model defined at the slice level can be applied to all blocks belonging to the slice.

[00179] Alternatively, the affine motion model of the current block may be determined based on the inter-image affine prediction mode of the current block. For example, when the affine merging mode is applied, the affine motion model of the current block can be defined as a 4-parameter motion model. On the other hand, when the advanced affine motion vector prediction mode is applied, information for determining the affine motion model of the current block can be encoded and transmitted by a bit stream. For example, when the advanced affine motion vector prediction mode is applied to the current block, the affine motion model of the current block can be determined based on a 1-bit flag in the form “affine_type_flag”.

[00180] The affine source vector of the current block can then be obtained (S1102). When a 4-parameter affine motion model is selected, motion vectors at two control points of the current block can be obtained. On the other hand, when the 6-parameter affine motion model is selected, the motion vectors at the three control points of the current block can be obtained. The motion vector at a control point can be called an affine source vector. The reference point may include at least one of the top left corner, top right corner, and bottom left corner of the current block.

[00181] In FIG. 12 is a view showing an example of affine source vectors of each affine motion model.

[00182] In the 4-parameter affine motion model, affine source vectors can be obtained for two of the upper left corner, upper right corner and lower left corner. For example, as shown in the example of FIG. 12(a), when the 4-parameter affine motion model is selected, the affine vector can be obtained by using the affine source vector sv0 for the top left corner of the current block (for example, the top left sample (x0, y0)) and the affine source vector sv1 for the top the right corner of the current block (for example, the top-right reference (x1, y1)). You can also use an affine source vector for the bottom left corner instead of an affine source vector for the top left corner, or use an affine source vector for the bottom left corner instead of an affine source vector for the top right corner.

[00183] In the 6-parameter affine motion model, affine source vectors can be obtained for the upper left corner, upper right corner and lower left corner. For example, as shown in the example of FIG. 12(b), when the 6-parameter affine motion model is selected, the affine vector can be obtained by using the affine source vector sv0 for the top left corner of the current block (for example, the top left sample (x0, y0)), the affine source vector sv1 for the top the right corner of the current block (for example, top-right sample (x1, y1)) and the affine source vector sv2 for the bottom-left corner of the current block (for example, bottom-left sample (x2, y2)).

[00184] In the embodiment described below, in the 4-parameter affine motion model, the affine source vectors of the top left control point and the top right control point will be called the first affine source vector and the second affine source vector, respectively. In embodiments that use the first affine seed vector and the second affine seed vector described below, at least one of the first affine seed vector and the second affine seed vector may be replaced by the lower left reference point affine seed vector (third affine seed vector) or the affine source vector of the lower right control point (the fourth affine source vector).

[00185] In addition, in the 6-parameter affine motion model, the affine source vectors of the top left control point, top right control point and bottom left control point will be called the first affine source vector, the second affine source vector and the third affine source vector, respectively. In embodiments that use a first affine seed vector, a second affine seed vector, and a third affine seed vector described below, at least one of the first affine seed vector, the second affine seed vector, and the third affine seed vector may be replaced by an affine seed vector bottom right control point (the fourth affine source vector).

[00186] An affine vector can be obtained (S1103) for each sub-block by using affine source vectors. In this case, the affine vector represents the translational motion vector obtained from the affine source vectors. An affine subblock vector may be called an affine subblock motion vector or a subblock motion vector.

[00187] In FIG. 13 is a view showing an example of sub-block affine vectors in a 4-parameter motion model.

[00188] The affine subblock vector can be obtained based on the position of the reference point, the position of the subblock, and the affine source vector. For example, Equation 3 shows an example of obtaining an affine subblock vector.

[00189] Equation 3

[00190]

[00191]

[00192] In Equation 3, (x, y) denotes the position of the subblock. Here, the position of the sub-block indicates the position of the reference sample included in the sub-block. The reference sample may be a sample located in the upper left corner of the subblock, or a sample for which at least one of the x-axis and y-axis coordinates represents a center point. (x0, y0) denotes the position of the first control point and (sv0x, sv0y) denotes the first affine source vector. In addition, (x1, y1) denotes the position of the second control point and (sv1x, sv1y) denotes the second affine source vector.

[00193] When the first control point and the second control point correspond to the upper left corner and upper right corner of the current block, respectively, x1-x0 can be set to a value equal to the width of the current block.

[00194] Thereafter, motion compensated prediction can be performed (S1104) for each sub-block using the affine vector of each sub-block. By performing motion-compensated prediction, a prediction block for each sub-block can be generated. Sub-block prediction blocks can be set as prediction blocks of the current block.

[00195] Next, a prediction method performed between images using translational motion information will be described in detail.

[00196] Information about the movement of the current block can be obtained from information about the movement of another block. Here, the other block may be a block encoded/decoded by inter-picture prediction before the current block. Setting the motion information of the current block equal to the motion information of another block can be defined as a merging mode. In addition, setting the motion vector of another block as the motion vector prediction value of the current block can be set as an improved motion vector prediction mode.

[00197] In FIG. 14 is a flowchart showing the process of obtaining movement information of the current block using the merging mode.

[00198] A merge candidate of the current block may be obtained (S1401). The merge candidate of the current block may be obtained from a block encoded/decoded by inter-picture prediction before the current block.

[00199] In FIG. 15 is a view showing an example of candidate blocks used to obtain a merge candidate.

[00200] Candidate blocks may include at least one of adjacent blocks containing a sample adjacent to the current block or non-adjacent blocks containing a sample that is not adjacent to the current block. Next, the samples for determining candidate blocks are set as reference samples. In addition, a reference sample adjacent to the current block is called an adjacent reference sample, and a reference sample that is not adjacent to the current block is called a non-adjacent reference sample.

[00201] An adjacent reference sample may be included in an adjacent column of the leftmost column of the current block or an adjacent row of the topmost row of the current block. For example, when the coordinates of the top left sample of the current block are (0, 0), at least one of the block containing the reference sample at position (-1, H-1), the block containing the reference sample at position (W-1, - 1), a block containing a reference count at position (W, -1), a block containing a reference count at position (-1, H), and a block containing a reference count at position (-1, -1) can be used in as a candidate block. Referring to graphics materials, adjacent blocks of index 0-4 can be used as candidate blocks.

[00202] A non-adjacent reference count represents a count in which at least one of the x-axis distance and the y-axis distance from a reference count adjacent to the current block has a predetermined value. For example, at least one of a block containing a reference sample, in which the x-axis distance from the left reference sample is a predetermined value, a block containing a non-adjacent sample, in which the y-axis distance from the top reference sample is a predetermined value , and a block containing a non-adjacent sample in which the x-axis distance and the y-axis distance from the upper left reference sample are preset values, can be used as a candidate block. The preset values may be a natural number such as 4, 8, 12, 16 or the like. Referring to graphics, at least one of the index blocks 5-26 may be used as a candidate block.

[00203] A sample not located on the same vertical line, horizontal line, or diagonal line as an adjacent reference sample may be set as a non-adjacent reference sample.

[00204] In FIG. 16 is a view showing positions of reference samples.

[00205] As shown in the example of FIG. 16, the x-coordinates of the upper non-adjacent reference samples can be set different from the x-coordinates of the upper adjacent reference samples. For example, when the position of the top adjacent reference count is (W-1, -1), the position of the top non-neighboring reference count up to N away from the top adjacent reference count on the y-axis can be set to ((W/2)-1, -1-N), and the position of the top non-adjacent reference count, distant up to 2N from the top adjacent reference count on the y-axis, can be set to (0, -1-2N). That is, the position of the non-adjacent reference sample can be determined based on the position of the adjacent reference sample and the distance from the adjacent reference sample.

[00206] Hereinafter, a candidate block containing an adjacent reference sample of the candidate blocks is called an adjacent block, and a block containing a non-adjacent reference sample is called a non-adjacent block.

[00207] When the distance between the current block and a candidate block is greater than or equal to a threshold, the candidate block may be set as unavailable as a merge candidate. The threshold value may be determined based on the size of the code tree element. For example, the threshold may be set to the height (ctu_height) of the code tree element, or a value obtained by adding the offset to or subtracting the offset from the height (eg, ctu_height±N) of the code tree element. The offset N is a value preset in the encoder and decoder and can be set to 4, 8, 16, 32 or ctu_height.

[00208] When the difference between the y-coordinate of the current block and the y-coordinate of a sample included in the candidate block is greater than a threshold value, the candidate block may be determined to be unavailable as a merge candidate.

[00209] Alternatively, a candidate block that does not belong to the same code tree element as the current block may be set to unavailable as a merge candidate. For example, when a reference sample deviates from the top boundary of a code tree element to which the current block belongs, the candidate block containing the reference sample may be set unavailable as a merge candidate.

[00210] When the upper boundary of the current block is adjacent to the upper boundary of a code tree element, a plurality of candidate blocks are determined to be unavailable as a merge candidate, and thus the encoding/decoding efficiency of the current block may be reduced. To solve this problem, candidate blocks can be set so that the number of candidate blocks located on the left side of the current block is greater than the number of candidate blocks located on top of the current block.

[00211] In FIG. 17 is a view showing an example of candidate blocks used to obtain a merge candidate.

[00212] As shown in the example of FIG. 17, the top blocks belonging to the N top block columns of the current block and the left blocks belonging to the M left block columns of the current block can be set as candidate blocks. In this case, the number of left candidate blocks can be set to be greater than the number of top candidate blocks by setting M greater than N.

[00213] For example, the difference between the y-coordinate of a reference sample in the current block and the y-coordinate of an upper block that can be used as a candidate block can be set to be no greater than N times the height of the current block. In addition, the difference between the x-coordinate of the reference sample in the current block and the x-coordinate of the left block, which can be used as a candidate block, can be set to not exceed M times the width of the current block.

[00214] For example, in the example shown in FIG. 17, it is shown that blocks belonging to the top two block columns of the current block and blocks belonging to the left five block columns of the current block are set as candidate blocks.

[00215] As another example, when a candidate block does not belong to the same code tree element as the current block, a merge candidate may be obtained using a block belonging to the same code tree element as the current block, or a block containing a reference sample adjacent to the code tree element boundary, instead of a candidate block.

[00216] In FIG. 18 is a view showing an example in which the position of the reference count is changed.

[00217] When a reference sample is included in a code tree element different from the current block, and the reference sample is not adjacent to the code tree element boundary, a candidate block may be determined using a reference sample adjacent to the code tree element boundary instead of the reference sample.

[00218] For example, in the examples shown in FIGS. 18(a) and 18(b), when the upper boundary of the current block and the upper boundary of the code tree element are in contact with each other, the reference samples on top of the current block belong to a code tree element different from the current block. Of the reference samples belonging to a code tree element other than the current block, a reference sample that is not adjacent to the top boundary of the code tree element may be replaced by a sample adjacent to the top boundary of the code tree element.

[00219] For example, as shown in the example in FIG. 18(a), the reference sample at position 6 is replaced by a sample at position 6' located at the upper boundary of the code tree element, and, as shown in the example in FIG. 18(b), the reference sample at position 15 is replaced by the sample at position 15', located at the upper boundary of the code tree element. In this case, the y-coordinate of the replacement sample is replaced with a position adjacent to the code tree element, and the x-coordinate of the replacement sample can be set equal to the reference sample. For example, a sample at position 6' may have the same x-coordinate as a sample at position 6, and a sample at position 15' may have the same x-coordinate as a sample at position 15.

[00220] Alternatively, the value obtained by adding the offset to the x-coordinate of the reference sample or subtracting the offset from it may be set as the x-coordinate of the replacement sample. For example, when the x-coordinates of an adjacent reference sample located on top of the current block and a non-adjacent reference sample are the same, a value obtained by adding the offset to or subtracting the offset from the x-coordinate of the reference sample can be set as the x-coordinate of the replacement sample. This is intended to prevent a replacement sample replacing a non-adjacent reference sample from being placed in the same position as another non-adjacent reference sample or an adjacent reference sample.

[00221] In FIG. 19 is a view showing an example in which the position of the reference count is changed.

[00222] When replacing a reference sample that is included in a code tree element different from the current block, and which is not adjacent to the code tree element boundary, with a sample located on the code tree element boundary, the value obtained by adding the offset to the x coordinate of the reference reference or subtracting an offset from it, can be set as the x-coordinate of the replacement reference.

[00223] For example, in the example shown in FIG. 19, the reference sample at position 6 and the reference sample at position 15 can be replaced by the sample at position 6' and the sample at position 15', respectively, the y-coordinates of which are the same as the y-coordinates of the row adjacent to the upper boundary of the code tree element. In this case, the x-coordinate of the reference at position 6' can be set equal to the value obtained by subtracting W/2 from the x-coordinate of the reference sample at position 6, and the x-coordinate of the reference at position 15' can be set to the value obtained by subtracting W-1 from x coordinates of the reference reference at position 15.

[00224] Unlike the examples shown in FIGS. 18 and 19, the y-coordinate of the row located on top of the topmost row of the current block, or the y-coordinate of the upper boundary of the code tree element can be set as the y-coordinate of the replacement reference.

[00225] Although not shown, a sample replacing the reference sample may be determined based on the left border of the code tree element. For example, when the reference sample is not included in the same code tree element as the current block and is not adjacent to the left boundary of the code tree element, the reference sample may be replaced by a sample adjacent to the left boundary of the code tree element. In this case, the replacement sample may have a y-coordinate that is the same as the y-coordinate of the reference sample, or may have a y-coordinate obtained by adding the offset to or subtracting from the y-coordinate of the reference sample.

[00226] Thereafter, the block containing the replacement count can be set as a candidate block, and a merge candidate of the current block can be obtained based on the candidate block.

[00227] A merge candidate may also be obtained based on a temporary neighboring block included in the image that is different from the current block. For example, a fusion candidate may be obtained from a fusion block included in a fusion image.

[00228] The movement information of the merge candidate may be set equal to the movement information of the candidate block. For example, at least one of the motion vector, the reference image index, the prediction direction, and the bidirectional weight index of the candidate block may be set as the motion information of the fusion candidate.

[00229] A merge candidate list may be generated (S1402) containing the merge candidates. The merge candidates can be divided into a contiguous merge candidate obtained from an adjacent block adjacent to the current block and a non-adjacent merge candidate obtained from a non-adjacent block.

[00230] The indices of the merge candidates in the list of merge candidates may be assigned in a predetermined order. For example, the index assigned to an adjacent merge candidate may have a value less than the index assigned to a non-adjacent merge candidate. Alternatively, an index may be assigned to each of the merge candidates based on the index of each block shown in FIG. 15 or 17.

[00231] When a plurality of merger candidates are included in the merger candidate list, at least one of the plurality of merger candidates may be selected (S1403). In this case, information indicating whether movement information of the current block is obtained from an adjacent merge candidate may be transmitted by a bitstream. The information may be a 1-bit flag. For example, the isAdjancentMergeFlag syntax element indicating whether the current block's movement information is derived from an adjacent merge candidate may be conveyed via a bitstream. When the value of the isAdjancentMergeFlag syntax element is 1, information about the movement of the current block can be obtained based on the adjacent merge candidate. On the other hand, when the value of the isAdjancentMergeFlag syntax element is 0, information about the movement of the current block can be obtained based on the non-adjacent merge candidate.

[00232] Table 1 shows a syntax table containing the isAdjancentMergeFlag syntax element.

[00233] Table 1

[00234] Information to indicate any of a plurality of merge candidates may be transmitted via a bit stream. For example, information indicating the index of any of the merge candidates included in the list of merge candidates may be transmitted by a bit stream.

[00235] When isAdjacentMergeflag is 1, a merge_idx syntax element may be passed indicating any of the adjacent merge candidates. The maximum value of the merge_idx syntax element can be set to the value obtained by subtracting 1 from the number of contiguous merge candidates.

[00236] When isAdjacentMergeflag is 0, a NA_merge_idx syntax element may be passed indicating any of the non-adjacent merge candidates. The NA_merge_idx syntax element represents the value obtained by subtracting the number of contiguous merge candidates from the index of the non-contiguous merge candidate. The decoder may select a non-contiguous merge candidate by adding the number of contiguous merge candidates with the index specified by NA_merge_idx.

[00237] When the number of merge candidates included in the merge candidate list is less than a threshold value, the merge candidate included in the inter-site traffic information list may be added to the merge candidate list. In this case, the threshold may be the maximum number of merge candidates that the list of merge candidates can contain, or a value obtained by subtracting the offset from the maximum number of merge candidates. The offset may be a natural number such as 1, 2, or the like. The list of inter-hop traffic information may include a merge candidate obtained based on a block encoded/decoded before the current block.

[00238] The inter-section motion information list contains a merge candidate obtained from a block encoded/decoded based on inter-picture prediction in the current picture. For example, the motion information of a fusion candidate included in the inter-section motion information list may be set equal to the motion information of a block encoded/decoded based on inter-picture prediction. Here, the motion information may comprise at least one of a motion vector, a reference image index, a prediction direction, and a bidirectional weight index.

[00239] For convenience of explanation, a merge candidate included in the inter-site traffic information list will be referred to as an inter-site merge candidate.

[00240] The maximum number of merge candidates that can contain a list of inter-section traffic information can be preset by the encoder and decoder. For example, the maximum number of merge candidates that can be included in the inter-site traffic information list can be 1, 2, 3, 4, 5, 6, 7, 8 or more (eg, 16).

[00241] Alternatively, information indicating the maximum number of merge candidates in the inter-section traffic information list may be transmitted by a bitstream. Information can be transferred at the sequence, image or slice level.

[00242] Alternatively, the maximum number of cross-section motion information list merging candidates may be determined according to the image size, slice size, or code tree element size.

[00243] The list of inter-section motion information may be initialized by an image element, a slice, a tile, a packet, a code tree element, or a line of code tree elements (row or column). For example, when a slice is initialized, the inter-slice traffic information list is also initialized, and the inter-slice traffic information list may not contain any merge candidate.

[00244] Alternatively, information indicating whether or not to initialize a list of inter-section traffic information may be transmitted via a bit stream. Information can be transferred at the slice, tile, packet or block level. Until the information indicates initialization of the inter-section traffic information list, a preconfigured inter-section traffic information list may be used.

[00245] Alternatively, information regarding the initial inter-slice fusion candidate may be conveyed by a set of image parameters or a slice header. Despite slice initialization, the list of inter-partition traffic information may contain an initial inter-partition merge candidate. Accordingly, a cross-section merge candidate may be used for a block that represents the first encoding/decoding target in the slice.

[00246] The blocks are encoded/decoded according to the encoding/decoding order, and the blocks encoded/decoded based on the prediction performed between pictures can be sequentially set as a fusion candidate between sections according to the encoding/decoding order.

[00247] In FIG. 20 is a flowchart showing the process of updating the inter-section traffic information list.

[00248] When inter-picture prediction is performed (S2001) on the current block, an inter-patch fusion candidate can be obtained (S2002) based on the current block. The movement information of a merge candidate between blocks may be set equal to the movement information of the current block.

[00249] When the inter-section traffic information list is empty (S2003), the inter-section merging candidate obtained based on the current block can be added (S2004) to the inter-section traffic information list.

[00250] When the inter-section traffic information list already contains an inter-section merging candidate (S2003), redundancy check can be performed (S2005) on the traffic information of the current block (or the inter-section merging candidate obtained based on the current block) (S2005). . The redundancy check is to determine whether the movement information of the inter-section merge candidate previously stored in the inter-section movement information list and the movement information of the current block are the same. Redundancy checking may be performed on all inter-site merging candidates previously stored in the inter-site traffic information list. Alternatively, redundancy checking may be performed on inter-site fusion candidates having an index that is greater than a threshold value or less than a threshold value from among the inter-site fusion candidates previously stored in the inter-site traffic information list.

[00251] When an inter-section fusion candidate having the same motion information as the motion information of the current block is not included, the inter-section fusion candidate obtained based on the current block can be added (S2008) to the list of information about movement between areas. Determining whether the fusion candidates are the same can be made based on whether the motion information (eg, motion vector and/or reference image index) of the fusion candidates is the same between regions.

[00252] In this case, when the maximum number of inter-area merging candidates is already stored in the inter-area traffic information list (S2006), the most senior inter-area merging candidates are deleted (S2007), and the inter-area merging candidate obtained based on of the current block can be added (S2008) to the inter-section movement information list.

[00253] Each of the cross-region fusion candidates may be identified by an index. When an inter-site merge candidate obtained from the current block is added to the inter-site traffic information list, the lowest index (for example, 0) is assigned to the inter-site merge candidate, and the indices of previously stored inter-site merge candidates may be incremented by 1 In this case, when the maximum number of inter-site merge candidates has already been stored in the inter-site traffic information list, the inter-site merge candidate having the largest index is deleted.

[00254] Alternatively, when an inter-site merge candidate obtained from the current block is added to the inter-site traffic information list, the inter-site merge candidate may be assigned the highest index. For example, when the number of inter-site fusion candidates previously stored in the inter-site traffic information list is less than the maximum value, an index having the same value as the number of previously stored inter-site fusion candidates may be assigned to the inter-site fusion candidate . Alternatively, when the number of inter-site fusion candidates previously stored in the inter-site traffic information list is the same as the maximum value, the inter-site fusion candidate may be assigned an index subtracting 1 from the maximum value. Additionally, the inter-site merge candidate having the smallest index is removed, and the indices of the remaining previously stored inter-site merge candidates may be decremented by 1.

[00255] In FIG. 21 is a view showing an embodiment of updating a cross-site merge candidate list.

[00256] Presumably, since the inter-site merge candidate obtained from the current block is added to the list of inter-site merge candidates, the largest index is assigned to the inter-site merge candidate. In addition, presumably the maximum number of cross-site merge candidates is already stored in the inter-site merge candidate list.

[00257] When an inter-site merge candidate HmvpCand[n+1] obtained from the current block is added to the inter-site merge candidate list HmvpCandList, the inter-site merge candidate HmvpCand[0] having the smallest index among the previously stored candidates for inter-chunk merge is removed, and the indices of the remaining inter-chunk merge candidates may be decremented by 1. Additionally, the index of the inter-chunk merge candidate HmvpCand[n+1] obtained from the current block may be set to the maximum value (n in example shown in Fig. 21).

[00258] When an inter-site fusion candidate that is the same as an inter-site fusion candidate obtained based on the current block is stored previously (S2005), the inter-site fusion candidate obtained based on the current block may not be added (S2009 ) to the list of information about movement between sections.

[00259] Alternatively, since the inter-site fusion candidate obtained based on the current block is added to the inter-site traffic information list, a previously stored inter-site fusion candidate that is the same as the inter-site fusion candidate may be deleted. In this case, an effect similar to updating the index of a previously saved merge candidate between sites is achieved.

[00260] In FIG. 22 is a view showing an example in which the index of a previously stored inter-site merge candidate is updated.

[00261] When the index of a previously stored inter-site merge candidate mvCand, which is the same as the inter-site merge candidate mvCand obtained based on the current block, is hIdx, the previously stored inter-site merge candidate is deleted, and the indexes of the inter-site merge candidates merges between regions having an index that is greater than hIdx may be reduced by 1. For example, in the example shown in FIG. 22, it is shown that HmvpCand[2], which is the same as mvCand, is removed from the inter-section traffic information list HvmpCandList, and the indices HmvpCand[3]-HmvpCand[n] are decreased by 1.

[00262] In addition, the inter-site fusion candidate mvCand obtained based on the current block may be added to the end of the inter-site traffic information list.

[00263] Alternatively, an index assigned to a previously stored inter-partition merge candidate that is the same as an inter-partition merge candidate obtained based on the current block may be updated. For example, the index of a previously stored cross-site merge candidate may be changed to a minimum value or a maximum value.

[00264] It may be set not to add movement information of blocks included in a predetermined area to the inter-area movement information list. For example, an inter-area fusion candidate obtained based on the movement information of a block included in the fusion processing area may not be added to the inter-area movement information list. Since the encoding/decoding order is not determined for the blocks included in the fusion processing region, it is inappropriate to use the motion information of any of the blocks for inter-picture prediction of another block. Accordingly, inter-section fusion candidates obtained based on blocks included in the fusion processing area may not be added to the inter-section traffic information list.

[00265] When motion-compensated prediction is performed by a sub-block element, an inter-region fusion candidate may be obtained based on the motion information of an example sub-block of a plurality of sub-blocks included in the current block. For example, when a subblock merge candidate is used for the current block, an inter-section merge candidate may be obtained based on the motion information of an example subblock of subblocks.

[00266] The motion vectors of the sub-blocks can be obtained in the following order. First, one of the merge candidates included in the list of merge candidates of the current block is selected, and an initial shift vector (shVector) can be obtained based on the motion vector of the selected merge candidate. Then, the shifted subblock whose reference sample position is (xColSb, yColSb) can be obtained as an initial shift vector, which is added at the reference sample position (for example, the top left sample or the center sample) of each subblock in the coding block. Equation 4 shows the equation for obtaining the shifted subblock.

[00267] Equation 4

[00268]

[00269] Then, the motion vector of the aligned block corresponding to the center position of the subblock having (xColSb, yColSb) can be set as the motion vector of the subblock having (xSb, ySb).

[00270] An exemplary sub-block may refer to a sub-block containing the top left sample or the sample in the center of the current block.

[00271] In FIG. 23 is a view showing the position of an illustrative sub-block.

[00272] In FIG. 23(a) shows an example in which a subblock located at the top left of the current block is set as an example subblock, and FIG. 23(b) shows an example in which a subblock located at the center of the current block is set as an example subblock. When motion-compensated prediction is performed by a sub-block element, a candidate for merging between portions of the current block can be obtained based on the motion vector of the sub-block containing the top-left sample of the current block or the sub-block containing the sample in the center of the current block.

[00273] It can be determined whether or not to use the current block as a cross-section fusion candidate based on the inter-image prediction mode of the current block. For example, a block encoded/decoded based on an affine motion model may be set unavailable as a candidate for cross-patch merging. Accordingly, although the current block is encoded/decoded by inter-picture prediction, when the inter-picture prediction mode of the current block is an affine prediction mode, the inter-section motion information list may not be updated based on the current block.

[00274] Alternatively, an inter-region fusion candidate may be obtained based on at least one sub-block vector of the sub-blocks included in the block encoded/decoded based on the affine motion model. For example, a cross-section merge candidate may be obtained using a sub-block located on the top left side, a sub-block located in the center, or a sub-block located on the top right side of the current block. Alternatively, the average of the subblock vectors of the plurality of subblocks may be set as the motion vector of a cross-section fusion candidate.

[00275] Alternatively, a cross-section fusion candidate may be obtained based on the average of the affine source vectors of the block encoded/decoded based on the affine motion model. For example, the average of at least one of the first affine source vector, the second affine source vector, and the third affine source vector of the current block may be set as the motion vector of the cross-section fusion candidate.

[00276] Alternatively, a list of inter-patch motion information may be configured for each inter-picture prediction mode. For example, at least one of a list of inter-lot motion information for a block encoded/decoded by intra-block copying, a list of inter-lot motion information for a block encoded/decoded based on a translational motion model, and a list of inter-lot motion information may be defined. sections for a block encoded/decoded based on the affine motion model. According to the prediction mode performed between images of the current block, any of a plurality of inter-section motion information lists can be selected.

[00277] In FIG. 24 is a view showing an example in which a list of inter-section motion information is generated for each inter-image prediction mode.

[00278] When a block is encoded/decoded based on a non-affine motion model, the inter-site fusion candidate mvCand obtained based on the block may be added to the inter-site non-affine motion information list HmvpCandList. On the other hand, when a block is encoded/decoded based on an affine motion model, the inter-site fusion candidate mvAfCand obtained based on the block may be added to the inter-site affine motion information list HmvpAfCandList.

[00279] Affine source vectors of a block encoded/decoded based on the affine motion model may be stored in a cross-section fusion candidate derived from the block. Accordingly, the cross-section merge candidate can be used as a merge candidate to obtain the affine source vector of the current block.

[00280] In addition to the inter-section traffic information list described above, an additional inter-section traffic information list may be specified. In addition to the inter-section traffic information list described above (hereinafter referred to as the first inter-section traffic information list), a long-term traffic information list (hereinafter referred to as the second inter-section traffic information list) can be defined. In this case, the long-term motion information list contains long-term merge candidates.

[00281] When both of the first inter-area traffic information list and the second inter-site traffic information list are empty, first inter-site merging candidates may be added to the second inter-site traffic information list. Only after the number of available inter-site fusion candidates reaches the maximum number in the second inter-site traffic information list, the inter-site fusion candidates can be added to the first inter-site traffic information list.

[00282] Alternatively, one inter-site fusion candidate may be added to both of the second inter-site traffic information list and the first inter-site traffic information list.

[00283] In this case, the second inter-section traffic information list whose configuration is completed may no longer be updated. Alternatively, when the decoded slice is greater than or equal to the predetermined slice ratio, the second inter-slice motion information list may be updated. Alternatively, the second list of inter-leg traffic information may be updated for every N code tree element lines.

[00284] On the other hand, the first list of inter-section motion information may be updated at any time when a block encoded/decoded by inter-picture prediction is generated. However, it may be determined not to use the inter-site fusion candidate added to the second inter-site traffic information list to update the first inter-site traffic information list.

[00285] Information for selecting any of the first list of inter-section traffic information and the second list of inter-section traffic information may be transmitted by a bit stream. When the number of merger candidates included in the merger candidate list is less than a threshold value, the merger candidates included in the inter-site traffic information list specified by the information may be added to the merger candidate list.

[00286] Alternatively, the list of inter-patch motion information may be selected based on the size and shape of the current block, the prediction mode performed between images, whether bidirectional prediction is provided, whether motion vector refinement is provided, or whether triangular partitioning is provided .

[00287] Alternatively, although an inter-site fusion candidate included in the first inter-site traffic information list is added, when the number of fusion candidates included in the fusion candidate list is less than the maximum number of fusion candidates, the inter-site merging included in the second inter-site traffic information list may be added to the merging candidate list.

[00288] In FIG. 25 is a view showing an example in which a cross-section merging candidate included in the long-term traffic information list is added to the merging candidate list.

[00289] When the number of fusion candidates included in the fusion candidate list is less than the maximum number, the inter-site fusion candidates included in the first inter-site traffic information list HmvpCandList may be added to the fusion candidate list. When the number of fusion candidates included in the fusion candidate list is less than the maximum number, although inter-site fusion candidates included in the first inter-site traffic information list are added to the fusion candidate list, the fusion candidates between sites included in the long-term traffic information list HmvpLTCandList can be added to the list of merge candidates.

[00290] Table 2 shows the process of adding cross-section fusion candidates included in the long-term traffic information list to the fusion candidate list.

[00291] Table 2

[00292] The cross-section fusion candidate may be set to contain additional information in addition to the traffic information. For example, size, shape, or block splitting information may be additionally stored for a cross-section merge candidate. When constructing a list of merge candidates of the current block, only inter-partition merge candidates having size, shape, or partitioning information that are the same as or similar to those of the current block are used among the inter-partition merge candidates, or inter-partition merge candidates. sections having size, shape, or partitioning information that are the same as or similar to those of the current block may be added to the merge candidate list first.

[00293] Alternatively, a list of inter-region movement information may be generated for each of the size, shape, or block partition information. From the plurality of inter-lot traffic information lists, a list of candidates for merging a current block may be generated using a list of inter-lot traffic information corresponding to the shape, size or partition information of the current block.

[00294] When the number of merge candidates included in the merge candidate list of the current block is less than a threshold value, inter-site merge candidates included in the inter-site traffic information list may be added to the merge candidate list. The adding process is performed in ascending or descending order based on the index. For example, the cross-site merge candidate that has the largest index may be added to the merge candidate list first.

[00295] When it is necessary to add an inter-site fusion candidate included in the inter-site traffic information list to the fusion candidate list, redundancy checking may be performed between the inter-site fusion candidate and the fusion candidates previously stored in the fusion candidate list .

[00296] For example, Table 3 shows a process in which a cross-site merge candidate is added to a list of merge candidates.

[00297] Table 3

[00298] Redundancy checking can only be performed on some inter-site merging candidates included in the inter-site traffic information list. For example, redundancy checking may be performed only on cross-site merge candidates having an index that is greater than a threshold value or less than a threshold value. Alternatively, redundancy checking may be performed on only the N merge candidates having the largest index or the N merge candidates having the smallest index.

[00299] Alternatively, redundancy checking may be performed on only some of the merge candidates previously stored in the merge candidate list. For example, redundancy checking may be performed only on a merge candidate having an index that is greater than a threshold value, or less than a threshold value, or on a merge candidate derived from a block at a particular position. Here, the particular position may comprise at least one of a left adjacent block, an upper adjacent block, an upper right adjacent block, and a lower left adjacent block of the current block.

[00300] In FIG. 26 is a view showing an example in which redundancy checking is performed on only some of the merge candidates.

[00301] When it is necessary to add a site-merge candidate HmvpCand[j] to the merge candidate list, redundancy checking may be performed on the site-merge candidate with two merge candidates mergeCandList[NumMerge-2] and mergeCandList[NumMerge-1 ], having the largest indices. In this case, NumMerge may represent the number of spatial merge candidates and temporal merge candidates that are available.

[00302] Unlike the example shown in the graphic, where it is necessary to add a cross-site merge candidate HmvpCand[j] to the list of merge candidates, redundancy checking can be performed on a cross-site merge candidate with no more than two candidates for merge with the smallest index. For example, you can check whether mergeCandList[0] and mergeCandList[1] are the same as HmvpCand[j]. Alternatively, redundancy checking may be performed only on merger candidates obtained at a particular location. For example, redundancy checking may be performed on at least one of a merge candidate obtained from an adjacent block located on the left side of the current block and a merge candidate obtained from an adjacent block located on top of the current block. When a merge candidate obtained at a particular location does not exist in the merge candidate list, the cross-site merge candidate may be added to the merge candidate list without having a redundancy check.

[00303] When a fusion candidate that is the same as the first inter-site fusion candidate is detected, and redundancy check is performed on the second inter-site fusion candidate, redundancy check is performed on the fusion candidate that is the same as the first candidate for merging between sites may be skipped.

[00304] In FIG. 27 is a view showing an example in which the redundancy check is skipped for a particular merge candidate.

[00305] When it is necessary to add an inter-site merge candidate HmvpCand[i] having index i to the merge candidate list, redundancy checking is performed between the inter-site merge candidate and the merge candidates previously stored in the merge candidate list. In this case, when a merge candidate mergeCandList[j] that is the same as an inter-site merge candidate HmvpCand[i] is detected, redundancy checking may be performed between the inter-site merge candidate HmvpCand[i-1] having the index i-1, and merge candidates without adding the cross-site merge candidate HmvpCand[i] to the list of merge candidates. In this case, the redundancy check between the cross-section merge candidate HmvpCand[i-1] and the merge candidate mergeCandList[j] may be omitted.

[00306] For example, in the example shown in FIG. 27, it is determined that HmvpCand[i] and mergeCandList[2] are the same. Accordingly, HmvpCand[i] is not added to the merge candidate list, and redundancy checking can be performed on HmvpCand[i-1]. In this case, the redundancy check between HvmpCand[i-1] and mergeCandList[2] can be omitted.

[00307] When the number of merge candidates included in the current block's merge candidate list is less than a threshold value, at least one of the paired merge candidate and the null merge candidate may be further included in addition to the inter-block merge candidate . A paired fusion candidate means a fusion candidate having the average of the motion vectors of two or more fusion candidates as a motion vector, and a zero fusion candidate means a fusion candidate having a motion vector of 0.

[00308] A merge candidate may be added to the list of merge candidates of the current block in the following order.

[00309] Spatial merge candidate - Temporal merge candidate - Inter-site merge candidate - (Inter-site affine merge candidate) - Pairwise merge candidate - Null merge candidate.

[00310] A spatial merge candidate means a merge candidate obtained from at least one of an adjacent block and a non-neighboring block, and a temporal merge candidate means a merge candidate obtained from a previous reference image. The inter-region affine fusion candidate represents the inter-region fusion candidate obtained from the block encoded/decoded by the affine motion model.

[00311] The list of inter-section motion information may also be used in an advanced motion vector prediction mode. For example, when the number of motion vector prediction candidates included in the motion vector prediction candidate list of the current block is less than a threshold value, an inter-section fusion candidate included in the inter-section motion information list may be set as a motion vector prediction candidate for the current block. block. Specifically, the motion vector of the cross-section fusion candidate may be set as the motion vector prediction candidate.

[00312] When any of the motion vector prediction candidates included in the motion vector prediction candidate list of the current block is selected, the selected candidate may be set as the motion vector predictor of the current block. Then, after decoding the residual motion vector coefficient of the current block, the motion vector of the current block can be obtained by adding a motion vector predictor and a residual motion vector coefficient.

[00313] The motion vector prediction candidate list of the current block may be configured in the following order.

[00314] Spatial motion vector prediction candidate - Temporal motion vector prediction candidate - Inter-site fusion candidate - (Inter-site affine fusion candidate) - Null motion vector prediction candidate.

[00315] A spatial motion vector prediction candidate means a motion vector prediction candidate obtained from at least one of an adjacent block and a non-neighboring block, and a temporal motion vector prediction candidate means a motion vector prediction candidate obtained from a previous reference picture. The inter-region affine fusion candidate represents the inter-region motion vector prediction candidate obtained from the block encoded/decoded by the affine motion model. The zero motion vector prediction candidate represents a candidate having a motion vector value of 0.

[00316] After selecting a merge candidate of the current block, the motion vector of the selected merge candidate is set as the initial motion vector, and a prediction can be performed for the current block using the motion vector obtained by adding the offset vector to or subtracting from the initial motion vector with motion compensation. Obtaining a new motion vector by adding or subtracting a displacement vector from a fusion candidate's motion vector can be specified as a way to encode the difference in fusion motion vectors.

[00317] Information indicating whether to use a merge offset encoding method may be transmitted via a bit stream. The information may be a merge_offset_vector_flag consisting of one bit. For example, when the value of merge_offset_vector_flag is 1, it indicates that the merge motion vector difference encoding method is applied to the current block. When the merging motion vector difference encoding method is applied to the current block, the motion vector of the current block can be obtained by adding an offset vector to or subtracting from the motion vector of the merging candidate. When merge_offset_vector_flag is 0, it indicates that the merge motion vector difference encoding method is not applied to the current block. When the merge offset encoding method is not applied, the motion vector of the current block can be set as the motion vector of the merge candidate.

[00318] The flag can be transmitted only when the value of the skip flag indicating whether the skip mode is applied is true, or when the value of the merge flag indicating whether the merge mode is applied is true. For example, merge_offset_vector_flag may be encoded and transmitted when the value of skip_flag indicating whether the current block is in skip mode is 1, or when the value of merge_flag indicating whether the current block is in merge mode is 1.

[00319] When it is determined that the merge offset encoding method is applied to the current block, at least one of information indicating any of the merge candidates included in the merge candidate list, information indicating the magnitude of the offset vector, and information , indicating the direction of the displacement vector.

[00320] Information for determining the maximum number of merge candidates that the list of merge candidates can contain may be transmitted via a bitstream. For example, the maximum number of merge candidates that a list of merge candidates can contain can be set to an integer of 6 or less.

[00321] When determining that the merging offset encoding method is applied to the current block, only the maximum number of merging candidates set in advance can be set as the initial motion vector of the current block. That is, the number of merge candidates that can be used by the current block can be determined adaptively according to whether the merge offset encoding method is applied. For example, when the value of merge_offset_vector_flag is set to 0, the maximum number of merge candidates that can be used by the current block can be set to M, while when the value of merge_offset_vector_flag is set to 1, the maximum number of merge candidates that can be used by the current block , can be set to N. In this case, M denotes the maximum number of merge candidates that the list of merge candidates can contain, and N denotes an integer that is less than or equal to M.

[00322] For example, when M is 6 and N is 2, two merge candidates having the smallest index among the merge candidates included in the merge candidate list may be set as available for the current block. Accordingly, the motion vector of a merge candidate having an index value of 0 or the motion vector of a merge candidate having an index value of 1 can be set as the initial motion vector of the current block. When M and N are equal (for example, when M and N are equal to 2), all merge candidates included in the list of merge candidates can be set as available for the current block.

[00323] Alternatively, whether a neighboring block can be used as a merging candidate can be determined based on whether a merging motion vector difference encoding method is applied to the current block. For example, when the value of merge_offset_vector_flag is 1, at least one of an adjacent block adjacent to the upper right corner of the current block, an adjacent block adjacent to the upper left corner, and an adjacent block adjacent to the lower left corner may be set as unavailable as merger candidate. Accordingly, when the merging motion vector difference encoding method is applied to the current block, the motion vector of at least one of an adjacent block adjacent to the upper right corner of the current block, an adjacent block adjacent to the upper left corner, and an adjacent block adjacent to the lower left angle, may not be set as the initial motion vector. Alternatively, when the value of merge_offset_vector_flag is 1, a temporary neighbor of the current block may be set to unavailable as a merge candidate.

[00324] When the merge motion vector difference encoding method is applied to the current block, it may be set not to use at least one of the paired merge candidate and the null merge candidate. Accordingly, when the value of merge_offset_vector_flag is 1, at least one of the paired merge candidate and the null merge candidate may not be added to the merge candidate list even though the number of merge candidates included in the merge candidate list is less than the maximum quantities.

[00325] The motion vector of the merge candidate may be set as the starting motion vector of the current block. In this case, when the number of merge candidates that can be used by the current block is multiple, information indicating any of the plurality of merge candidates can be transmitted by the bit stream. For example, when the maximum number of merge candidates that a list of merge candidates can contain is greater than 1, merge_idx information indicating any of a plurality of merge candidates may be transmitted via the bit stream. That is, in the merge offset encoding method, a merge candidate may be indicated by merge_idx information to indicate any of a plurality of merge candidates. The initial motion vector of the current block can be set to the motion vector of the merge candidate specified by merge_idx.

[00326] On the other hand, when the number of merge candidates that can be used by the current block is 1, transmission of information to indicate the merge candidate may be skipped. For example, when the maximum number of merge candidates that a list of merge candidates can contain is 1 or less, passing merge_idx information to indicate the merge candidate may be omitted. That is, in the merge offset encoding method, when the merge candidate list contains one merge candidate, encoding of the merge_idx information to indicate the merge candidate can be omitted, and the initial motion vector can be determined based on the merge candidate contained in the candidate list. for the merger. The motion vector of the merge candidate can be set as the initial motion vector of the current block.

[00327] As another example, after determining a merging candidate of the current block, it may be determined whether to apply a merging motion vector difference encoding method to the current block. For example, when the maximum number of merge candidates that a list of merge candidates can contain is greater than 1, merge_idx information may be passed to indicate any of the merge candidates. After selecting a merge candidate based on merge_idx, a merge_offset_vector_flag may be decoded indicating whether the merge motion vector difference encoding method is applied to the current block. Table 4 is a view showing a syntax table according to the above-described embodiment.

[00328] Table 4

[00329] As another example, after determining the merge candidate of the current block, whether to apply the merge motion vector difference encoding method to the current block can be determined only when the index of the determined merge candidate is less than the maximum number of merge candidates that can be used when applying the method of encoding the difference in motion vectors when merging. For example, a merge_offset_vector_flag indicating whether to apply the merge motion vector difference encoding method to the current block may be encoded and transmitted only when the merge_idx index information value is less than N. When the merge_idx index information value is greater than or equal to N, the merge_offset_vector_flag encoding may be missed. When the merge_offset_vector_flag encoding is omitted, it can be determined that the way the merge motion vector difference is encoded does not apply to the current block.

[00330] Alternatively, after determining the merge candidate of the current block, considering whether the determined merge candidate contains bidirectional motion information or unidirectional motion information, it can be determined whether to apply the merge motion vector difference encoding method to the current block. For example, merge_offset_vector_flag indicating whether to apply the merge motion vector difference encoding method to the current block can be encoded and transmitted only when the value of the merge_idx index information is less than N and the merge candidate selected by the index information contains information about bidirectional movement. Alternatively, a merge_offset_vector_flag indicating whether to apply the merge motion vector difference encoding method to the current block may be encoded and transmitted only when the value of the merge_idx index information is less than N and the merge candidate selected by the index information contains unidirectional information. movement.

[00331] Alternatively, whether to apply a merging motion vector difference encoding method may be determined based on at least one of the size of the current block, the shape of the current block, and whether the current block is in contact with a code tree element boundary. When at least one of the current block's size, the current block's shape, and whether the current block is in contact with a code tree element boundary does not satisfy a preset condition, encoding a merge_offset_vector_flag indicating whether to apply the motion vector difference encoding method to the current block merge may be skipped.

[00332] After selecting a merge candidate, the motion vector of the merge candidate can be set as the initial motion vector of the current block. Then, the displacement vector can be determined by decoding information indicating the magnitude of the displacement vector and information indicating the direction of the displacement vector. The displacement vector may have a horizontal direction component or a vertical direction component.

[00333] The information indicating the displacement vector module may be index information indicating any of the motion module candidates. For example, distance_idx index information indicating any of the motion module candidates may be transmitted via a bit stream. Table 5 shows the binary conversion of the distance_idx index information and the values of the DistFromMergeMV variable to determine the magnitude of the displacement vector according to distance_idx.

[00334] Table 5

[00335] The magnitude of the displacement vector can be obtained by dividing the DistFromMergeMV variable by a preset value. Equation 5 shows an example of determining the magnitude of the displacement vector.

[00336] Equation 5

[00337]

[00338] According to Equation 5, the magnitude of the offset vector can be set to the value obtained by dividing the DistFromMegeMV variable by 4, or the value obtained by shifting the DistFromMergeMV variable left by 2.

[00339] More motion module candidates or fewer motion module candidates may be used than in the example shown in Table 5, or the range of motion vector offset amount candidates may be set differently than in the example shown in Table 5. For example, the magnitude of the horizontal direction component or the vertical direction component of the displacement vector can be set to not exceed 2 sample distances. Table 6 shows the binary conversion of the distance_idx index information and the values of the DistFromMergeMV variable to determine the magnitude of the displacement vector according to distance_idx.

[00340] Table 6

[00341] Alternatively, the candidate range for the amount of motion vector offset may be set differently based on the accuracy of the motion vector. For example, when the precision of the motion vector for the current block is a fractional number of pixels, the values of the DistFromMergeMV variable corresponding to the distance_idx index information values may be set to 1, 2, 4, 8, 16, or the like. Here, the fractional number of pixels includes at least one of 1/16 of a pixel, one-eighth of a pixel, one-quarter of a pixel, and one-half of a pixel. On the other hand, when the precision of the motion vector for the current block is an integer number of pixels, the values of the DistFromMergeMV variable corresponding to the values of the distance_idx index information can be set to 4, 8, 16, 32, 64, etc. That is, the table to be accessed to determine the DistFromMergeMV variable may be set differently according to the precision of the motion vector for the current block.

[00342] For example, when the motion vector precision of the current block or merge candidate is a quarter pixel, the DistFromMergeMV variable specified by distance_idx can be obtained using Table 5. On the other hand, when the motion vector precision of the current block or merge candidate is an integer number of pixels, the value of the DistFromMergeMV variable can be the value obtained by taking N times the value (e.g., 4 times the value) of the value of the DistFromMergeMV variable specified by distance_idx in Table 5.

[00343] Information for determining motion vector accuracy may be transmitted via a bit stream. For example, information can be transferred at the sequence, image, slice, or block level. Accordingly, the range of motion module candidates can be set differently according to information related to motion vector precision transmitted by the bitstream. Alternatively, the accuracy of the motion vector can be determined based on the merge candidate of the current block. For example, the motion vector precision of the current block can be set to be equal to the motion vector precision of the merge candidate.

[00344] Alternatively, information for determining the search range of the offset vector may be transmitted via a bit stream. At least one of the number of motion module candidates, the minimum value of the motion module candidates, and the maximum value of the motion module candidates may be determined based on the search range. For example, a merge_offset_vector_flag may be passed via the bitstream to define the offset vector search range. The information can be conveyed through a sequence header, an image header, or a slice header.

[00345] For example, when the value of merge_offset_extend_range_flag is 0, the magnitude of the offset vector can be set to not exceed 2. Accordingly, the maximum value of DistFromMergeMV can be set to 8. On the other hand, when the value of merge_offset_extend_range_flag is 1, the magnitude of the offset vector can be set so that it does not exceed 32 distances between readings. Accordingly, the maximum value of DistFromMergeMV can be set to 128.

[00346] The magnitude of the displacement vector may be determined using a flag indicating whether the magnitude of the displacement vector exceeds a threshold value. For example, a distance_flag may be transmitted via the bitstream indicating whether the magnitude of the displacement vector exceeds a threshold value. The threshold value can be 1, 2, 4, 8 or 16. For example, when distance_flag is 1, it indicates that the displacement vector magnitude is greater than 4. On the other hand, when distance_flag is 0, it indicates that the displacement vector magnitude is 4 or less.

[00347] When the magnitude of the displacement vector is greater than the threshold value, the difference value between the magnitude of the displacement vector and the threshold value can be obtained using the distance_idx index information. Alternatively, when the magnitude of the displacement vector is less than or equal to the threshold value, the magnitude of the displacement vector can be determined using the distance_idx index information. Table 7 is a syntax table showing the encoding process of distance_flag and distance_idx.

[00348] Table 7

[00349] Equation 6 shows an example of obtaining the DistFromMergeMV variable to determine the magnitude of the displacement vector using distance_flag and distance_idx.

[00350] Equation 6

[00351]

[00352] In Equation 6, the value of distance_flag can be set to 1 or 0. The value of distance_idx can be set to 1, 2, 4, 8, 16, 32, 64, 128, or the like. N denotes the coefficient determined by the threshold value. For example, when the threshold value is 4, N can be set to 16.

[00353] Information indicating the direction of the offset vector may be index information indicating any of the vector direction candidates. For example, direction_idx index information indicating any of the vector direction candidates may be conveyed via a bitstream. Table 8 shows the binary conversion of the index information direction_idx and the direction of the displacement vector according to direction_idx.

[00354] Table 8

[00355] In Table 8, sign[0] indicates the horizontal direction and sign[1] indicates the vertical direction. +1 indicates that the value of the x component or the y component of the displacement vector is positive (+), and -1 indicates that the value of the component The x or y component of the displacement vector is negative (-). Equation 7 shows an example of determining the displacement vector based on the magnitude and direction of the displacement vector.

[00356] Equation 7

[00357]

[00358] In Equation 7, offsetMV[0] denotes the vertical direction component of the offset vector, and offsetMV[1] denotes the horizontal direction component of the offset vector.

[00359] In FIG. 28 is a view showing a displacement vector according to the values of distance_idx indicating the magnitude of the displacement vector and direction_idx indicating the direction of the displacement vector.

[00360] As shown in the example of FIG. 28, the magnitude and direction of the displacement vector can be determined according to the values of distance_idx and direction_idx. The maximum magnitude of the displacement vector can be set so that it does not exceed a threshold value. In this case, the threshold value may have a value preset in the encoder and decoder. For example, the threshold could be 32 sample distances. Alternatively, the threshold value may be determined according to the magnitude of the initial motion vector. For example, a threshold value for the horizontal direction may be set based on the magnitude of the horizontal direction component of the initial motion vector, and a threshold value for the vertical direction may be set based on the magnitude of the vertical direction component of the initial motion vector.

[00361] When the merge candidate contains bidirectional motion information, the starting motion vector L0 of the current block may be set to the motion vector L0 of the merge candidate, and the starting motion vector L1 of the current block may be set to the motion vector L1 of the merge candidate. In this case, the offset vector L0 and the offset vector L1 can be determined taking into account the output order difference value between the fusion candidate reference image L0 and the current image (hereinafter referred to as the L0 difference value), and the output order difference value between the fusion candidate reference image L1 merge and the current image (hereinafter called the L1 difference value).

[00362] First of all, when the signs of the difference value L0 and the difference value L1 are the same, the offset vector L0 and the offset vector L1 can be set equal to each other. On the other hand, when the signs of the difference value L0 and the difference value L1 are different, the offset vector L0 can be set in the opposite direction to the offset vector L1.

[00363] The magnitude of the bias vector L0 and the magnitude of the bias vector L1 can be set equal to each other. Alternatively, the magnitude of the offset vector L1 can be determined by scaling the offset vector L0 based on the difference value L0 and the difference value L1.

[00364] For example, Equation 8 shows the offset vector L0 and the offset vector L1 when the signs of the difference value L0 and the difference value L1 are the same.

[00365] Equation 8

[00366]

[00367]

[00368] In Equation 8, offsetMVL0[0] indicates the horizontal direction component of the offset vector L0, and offsetMVL0[1] indicates the vertical direction component of the offset vector L0. offsetMVL1[0] indicates the horizontal direction component of the L1 offset vector, and offsetMVL1[1] indicates the vertical direction component of the L1 offset vector.

[00369] Equation 9 shows the L0 offset vector and the L1 offset vector when the signs of the difference value L0 and the difference value L1 are different.

[00370] Equation 9

[00371]

[00372]

[00373] More than four vector direction candidates may be specified. Tables 9 and 10 show examples in which eight vector direction candidates are given.

[00374] Table 9

[00375] Table 10

[00376] In Tables 9 and 10, when the absolute values of sign[0] and sign[1] are greater than 0, it indicates that the displacement vector is in the diagonal direction. When using Table 9, the moduli of the x-axis and y-axis components of the diagonal offset vector are set to abs(offsetMV), whereas when using Table 10, the moduli of the x-axis and y-axis components of the diagonal offset vector are set to abs(offsetMV/2).

[00377] In FIG. 29 is a view showing a displacement vector according to the values of distance_idx indicating the magnitude of the displacement vector and direction_idx indicating the direction of the displacement vector.

[00378] In FIG. 29(a) is a view showing an application example of Table 9, and FIG. 29(b) is a view showing an application example of Table 10.

[00379] Information for determining at least one of the number and size of vector direction candidates may be transmitted via a bit stream. For example, the merge_offset_direction_range_flag flag for identifying vector direction candidates may be transmitted via a bit stream. The flag can be passed at the sequence, image, or slice level. For example, when the flag value is 0, four vector direction candidates, an example of which is shown in Table 8, can be used. On the other hand, when the flag value is 1, eight vector direction candidates, an example of which is shown in Table 9 or Table 10, can be used. .

[00380] Alternatively, at least one of the number and sizes of vector direction candidates may be determined based on the magnitude of the displacement vector. For example, when the value of the DistFromMergeMV variable to determine the magnitude of the displacement vector is less than or equal to a threshold value, eight vector direction candidates can be used, an example of which is shown in Table 9 or Table 10. On the other hand, when the value of the DistFromMergeMV variable is greater than the threshold value, four can be used candidate for vector direction, an example of which is given in Table 8.

[00381] Alternatively, at least one of the number and size of vector direction candidates may be determined based on the x component value MVx and the y component value MVy of the initial motion vector. For example, when the difference between MVx and MVy or the absolute value of the difference is less than or equal to a threshold value, eight vector direction candidates can be used, an example of which is given in Table 9 or Table 10. On the other hand, when the difference between MVx and MVy or the absolute value of the difference greater than the threshold value, four vector direction candidates can be used, an example of which is given in Table 8.

[00382] The motion vector of the current block can be obtained by adding an offset vector to the initial motion vector. Equation 10 shows an example of determining the motion vector of the current block.

[00383] Equation 10

[00384]

[00385]

[00386] In Equation 10, mvL0 denotes the L0 motion vector of the current block, and mvL1 denotes the L1 motion vector of the current block. mergeMVL0 denotes the initial L0 motion vector of the current block (ie, the L0 motion vector of the merge candidate), and mergeMVL1 denotes the initial L1 motion vector of the current block. [0] indicates the horizontal direction component of the motion vector, and [1] indicates the vertical direction component of the motion vector.

[00387] Even when inter-image prediction is performed on each of the sub-elements after dividing the encoding block into a plurality of sub-elements, a merging motion vector difference encoding method can be applied. Here, performing inter-image prediction using a sub-element may include at least one of an advanced temporal motion vector prediction (ATMVP) method, a spatial temporal motion vector prediction (STMVP) method, and a triangular partitioning method.

[00388] For example, the initial motion vector can be obtained as follows from the ATMVP method.

[00389] First, an initial shift vector may be obtained using a motion vector of a merge candidate obtained from a neighbor block adjacent to the encoding block. In addition, a subblock shift block that is included in a coding block can be obtained using an initial shift vector. Equation 11 shows the position of the shift block.

[00390] Equation 11

[00391]

[00392] In Equation 11, (xColSb, yColSb) denotes the position of the upper left sample of the shift block, and (xSb, ySb) denotes the position of the upper left sample of the sub-block. shVector denotes the shift vector.

[00393] When a shift block is determined, the motion vector of a registration block at the same position as the shift block in the registration image can be set as the motion vector of the sub-block. That is, the motion vector of an overlapping block containing a sample located at (xColSb, yColSb) in the overlapping block can be set as the motion vector of a sub-block containing a sample located at (xSb, ySb).

[00394] When the triangular partitioning method is used, the encoding block can be partitioned into triangular sub-elements. For example, an encoding block may be divided into two sub-elements by a diagonal line connecting the upper left and lower right corners of the encoding block, or a diagonal line connecting the upper right and lower left corners of the encoding block.

[00395] In FIG. 30 is a view showing partitioning patterns of a coding block when applying the triangular partitioning method.

[00396] Motion information of each of the triangular sub-elements may be indicated by the fusion candidate. To achieve this, index information indicating any of the merge candidates can be passed for each sub-element. For example, the merge_1st_idx index information of the first sub-element may indicate a merge candidate of the first sub-element, and the merge_2nd_idx index information of the second sub-element may indicate a merge candidate of the second sub-element.

[00397] The initial motion vector of each of the sub-elements can be determined separately. For example, when an affine motion model is applied to an encoding block, affine vectors of subblocks that are obtained from affine source vectors of the encoding block can be set as initial motion vectors of the subblocks. The motion vector of each sub-block can be obtained by adding or subtracting the displacement vector to the initial motion vector.

[00398] When the merging motion vector difference encoding method is applied to an encoding block divided into a plurality of sub-elements, the plurality of sub-elements may be set to use the same offset vector. That is, the initial motion vector of each of the plurality of sub-elements can be changed using the same displacement vector.

[00399] Alternatively, the encoding block is divided into a plurality of sub-elements, and the offset vector of each sub-element can be determined separately. Accordingly, the offset vector of at least one of the subelements may be set differently from the offset vectors of the other subelements.

[00400] In FIG. 31 is a view showing an example in which the offset vectors of each of the sub-elements are set differently.

[00401] As shown in the example of FIG. 31, information distance_idx indicating the magnitude of the displacement vector and direction_idx indicating the direction of the displacement vector may be encoded and transmitted for each sub-element.

[00402] Alternatively, the magnitude of the offset vector can be set equally for all sub-elements, and the direction of the offset vector can be set separately for sub-elements. For example, the distance_idx value passed at the encoding level may be set to be shared among the subelements, and the direction_idx may be encoded and passed for each subelement.

[00403] Alternatively, the direction of the offset vector can be set the same for all sub-elements, and the magnitude of the offset vector can be set separately for sub-elements. For example, the direction_idx value passed at the encoding level could be set to be shared among the subelements, and the distance_idx could be encoded and passed for each subelement.

[00404] The merging motion vector difference encoding method can be applied to only some of the plurality of sub-elements generated by dividing the encoding block. For example, when the current block is divided into a first sub-element and a second sub-element, the motion vector of the first sub-element can be set equal to the motion vector of the merge candidate, and the motion vector of the second sub-element can be obtained by adding a displacement vector to the motion vector of the merge candidate.

[00405] Instead of transmitting information to determine the offset vector, the decoder may receive the offset vector. Specifically, the displacement vector can be obtained using the average of the horizontal direction gradients and the average of the vertical direction gradients of the prediction samples included in the subblock.

[00406] Here, a gradient can be obtained based on the difference between a reconstructed sample corresponding to a prediction sample in the reference image and a neighboring sample adjacent to the reconstructed sample. For example, the horizontal direction gradient may indicate the difference between the reconstructed sample and the reconstructed sample adjacent to the left and/or right sides, and the vertical direction gradient may indicate the difference between the reconstructed sample and the reconstructed sample adjacent to the top and/or bottom sides.

[00407] Of the fusion candidates included in the fusion candidate list, the fusion candidate having a motion vector obtained by adding or subtracting a displacement vector to or subtracting from the motion vector of the reference fusion candidate, from the fusion candidates included in the fusion candidate list merge can be added to the list of merge candidates. A fusion candidate having a motion vector obtained by adding or subtracting a displacement vector to or subtracting from the motion vector of a reference fusion candidate may be referred to as a refined fusion candidate.

[00408] The remaining motion information, except for the motion vector of the refined fusion candidate, can be set to the same as that of the reference fusion candidate.

[00409] In FIG. 32 is a view showing motion vector candidates that the refined merge candidate can take.

[00410] When the motion vector of the reference fusion candidate is (MvLX[0], MvLX[1]), the motion vector of the refined fusion candidate can be obtained by adding an offset to at least one of the x component and the y component of the motion vector of the reference candidate to merge or subtract from it. For example, the motion vector of the refined merge candidate can be set to (MvLX[0]+M, MvLX[1]), (MvLX[0]-M, MvLX[1]), (MvLX[0], MvLX[1] +M) or (MvLX[0], MvLX[1]-M). M denotes the magnitude of the displacement vector.

[00411] The reference merge candidate may be a merge candidate having a predetermined index value in the list of merge candidates. For example, the merge candidate having the smallest index value (i.e., the merge candidate having an index value of 0) or the merge candidate having the highest index value of the merge candidates included in the list of merge candidates may be established as a pivotal merger candidate. Alternatively, the inter-site merging candidate having the smallest index value or the inter-site merging candidate having the largest index value in the inter-site traffic information list may be set as the reference merging candidate.

[00412] Alternatively, the merge candidate having the smallest index value of the merge candidates having bidirectional traffic information may be set as the reference merge candidate. That is, when searching candidate blocks sequentially, the bidirectional merge candidate found first can be set as the reference merge candidate.

[00413] A base merge candidate may be selected based on the size of the current block, the shape of the current block, or whether the current block is in contact with a code tree element boundary. For example, when the current block has a square shape, or the current block has a non-square shape whose height is greater than its width, a merge candidate having an index of 0 or a merge candidate derived from a neighboring block located above the current block may be established as a pivotal merger candidate. When the current block has a non-square shape whose width is greater than its height, a merge candidate having an index of 1 or a merge candidate obtained from a neighboring block located to the left of the current block can be set as the reference merge candidate.

[00414] Alternatively, information indicating a reference merge candidate may be transmitted via a bitstream. The information may be index information indicating any of the merger candidates included in the list of merger candidates.

[00415] Information indicating whether to use the refined merge candidate may be transmitted via a bit stream. The information may be a 1-bit flag. When the flag value is 1, the refined merge candidate generated based on the reference merge candidate can be added to the list of merge candidates. On the other hand, when the flag value is 0, the list of merge candidates may not contain a refined merge candidate.

[00416] Alternatively, when the number of merge candidates previously added to the merge candidate list is less than the maximum number of merge candidates that the merge candidate list can contain, the refined merge candidate may be added to the merge candidate list. Here, the previously added merge candidates may include at least one of a spatial merge candidate, a temporal merge candidate, an inter-site merge candidate, and a pairwise merge candidate. For example, when the number of at least one of spatial merge candidates, temporal merge candidates, and inter-site merge candidates included in the merge candidate list is less than or equal to a threshold value, the refined merge candidate may be added to list of merger candidates.

[00417] Alternatively, when the number of merge candidates previously added to the merge candidate list is greater than or equal to a threshold, a refined merge candidate may be used.

[00418] The maximum number of merge candidates that the list of merge candidates can contain may be set differently according to whether a refined merge candidate is used. For example, when it is set not to use a refined merge candidate, the maximum number of merge candidates that can contain a list of merge candidates can be set to N, whereas when it is set to use a refined merge candidate, the maximum number of merge candidates that can contain a list of merge candidates, can be set to N+n.

[00419] The refined merge candidate may have an index that is greater than the merge candidates previously added to the list of merge candidates. For example, Table 11 shows an example of configuring a list of merge candidates.

[00420] Table 11

[00421] In Table 11, mergeCand[X] denotes a merge candidate having an index equal to X. mvLx[0] denotes the motion vector of the x component of the reference merge candidate, and mvLx[1] denotes the motion vector of the y component of the reference merge candidate. For example, when the reference merge candidate is mergeCand[0], mvLx[0] and mvLx[1] may indicate the motion vector of mergeCand[0].

[00422] The magnitude M of the offset vector may be preset in the encoder and decoder. For example, the magnitude M of the bias vector can be set to an integer that is less than or equal to 4, such as 1 or 4.

[00423] Alternatively, information for determining the offset vector may be transmitted via a bit stream. Information can be transferred at the sequence, image, slice or block level. For example, the displacement vector may be determined using at least one of distance_idx information for determining the magnitude of the displacement vector and direction_idx information for determining the direction of the displacement vector, as described above.

[00424] As shown in the example of Table 11, at least one refined merge candidate derived from the reference merge candidate may be added to the list of merge candidates. When there is a merge candidate having traffic information that is the same as that of the refined merge candidate from the previously added merge candidates, the refined merge candidate may not be added to the list of merge candidates. For example, when the refined merge candidate derived from the reference merge candidate mergeCand[0] is the same as any of the merge candidates mergeCand[1] through mergeCand[5], the refined merge candidate may not be added to the candidate list for the merger.

[00425] Alternatively, when there is a merge candidate having motion information that is the same as the refined merge candidate, the refined merge candidate can be re-obtained by changing the offset vector or resetting the merge candidate having the information motion, which is the same as the refined merger candidate as the refined merger candidate. For example, when the motion information of the refined merge candidate mergeCand[6] derived from the reference merge candidate mergeCand[0] is the same as that of the merge candidate mergeCand[2], the motion vector of the refined merge candidate mergeCand[ 6] can be changed to a value obtained by adding or subtracting the displacement vector to the fusion candidate motion vector [2]. For example, the motion vector mergeCand[6] can be changed from (mergeCand[0]_mxLx[0]+M, mergeCand[0]_mvLx[1]) to (mergeCand[2]_mxLx[0]+M, mergeCand[2] _mvLx[1]). Here mergeCand[X]_mvLx denotes the motion vector of the merge candidate having index X.

[00426] As another example, an offset vector may be determined using a merge refinement offset list containing at least one merge offset candidate. When the merge candidate specified by the current block index information is the reference merge candidate, the offset vector can be determined using the merge refinement offset list. Additionally, the motion vector of the current block can be obtained by adding or subtracting the displacement vector to or subtracting from the motion vector of the merge candidate. The reference merge candidate may be a merge candidate having a predetermined index value in the list of merge candidates. For example, of the merge candidates included in the list of merge candidates, the merge candidate having the smallest index value (i.e., the merge candidate having an index value of 0) or the merge candidate having the highest index value may be established as a pivotal merger candidate. Alternatively, the inter-site merging candidate having the smallest index value or the inter-site merging candidate having the largest index value in the inter-site traffic information list may be set as the reference merging candidate.

[00427] In FIG. 33 is a view showing a configuration of an offset list with merge refinement.

[00428] As shown in FIG. 33, it is assumed that the reference merge candidate is a merge candidate having an index of 6.

[00429] When the merge candidate index indicated by the merge_idx index information indicating any of the merge candidates is not 6, the motion vector of the merge candidate may be set to the motion vector of the current block.

[00430] On the other hand, when the merge candidate index specified by the merge_idx index information is 6, the offset vector can be obtained using the merge refinement offset list. Index information MrgOffset_idx indicating any of the merge offset candidates included in the merge refinement offset list may be transmitted via a bitstream.

[00431] When an offset vector is specified, the motion vector of the current block can be obtained by adding the offset vector to or subtracting from the motion vector of the reference merge candidate.

[00432] The merge refinement offset list may contain at least one merge offset candidate. For example, the number of merge offset candidates that contains the merge refinement offset list can be 4, 8, or 16.

[00433] In FIG. 34 and 35 are views showing displacement vectors indicated by merging displacement candidates.

[00434] In FIG. 34 shows an example in which the number of merge offset candidates is 8, and FIG. Figure 35 shows an example in which the number of merge displacement candidates is 16.

[00435] As shown in the example of FIG. 34(a), the offset vectors indicated by the merging offset candidates can be set so that the absolute value of the horizontal direction motion vector and/or the absolute value of the vertical direction motion vector can have a fixed value. Alternatively, as shown in the example of FIG. 35, the displacement vectors indicated by the fusion displacement candidates having an index that is less than the threshold value of the fusion displacement candidates may be set so that the absolute value of the horizontal direction motion vector and/or the absolute value of the vertical direction motion vector could have the first value, and the offset vectors specified by the other merging offset candidates could be set so that the absolute value of the horizontal direction motion vector and/or the absolute value of the vertical direction motion vector could have the second value.

[00436] Alternatively, as shown in FIG. 34(b), the displacement vectors indicated by the merging displacement candidates can be set so that the sum of the absolute value of the horizontal direction motion vector and the absolute value of the vertical direction motion vector can have a fixed value.

[00437] Multiple reference merge candidates may be established. For example, from the merger candidates included in the list of merger candidates, two merger candidates having the smallest index may be set as the reference merger candidates. Accordingly, when the merge candidate index specified by the merge_idx index information is 0 or 1, the offset vector can be obtained using the merge refinement offset list. Alternatively, the merger candidate having the smallest index among the merger candidates included in the list of merger candidates and the merger candidate having the largest index among the merger candidates included in the list of intersite merger candidates may be set as reference candidates. for the merger.

[00438] In the advanced motion vector prediction mode, the motion vector of the current block can be obtained by adding a motion difference vector to the motion prediction vector. A motion prediction vector of the current block may be determined based on a motion vector prediction candidate list containing at least one motion prediction candidate vector. For example, any of the candidate motion prediction vectors may be set as the motion prediction vector of the current block.

[00439] A motion vector prediction candidate may be obtained based on at least one of a spatially adjacent block of the current block and a temporally adjacent block of the current block.

[00440] In FIG. 36 is a view showing candidate blocks used for obtaining motion vector prediction candidates.

[00441] A spatially adjacent block may comprise top neighbor blocks located above the current block and left neighbor blocks located to the left of the current block. The upper adjacent blocks may contain at least one of a block B0 containing a sample located at (xCb+CbW, yCb-1), a block B1 containing a sample located at (xCb+CbW-1, yCb-1), a block B2 , containing the sample located at (xCb-1, yCb-1), and block B3 containing the sample located at (xCb, yCb-1). Here (xCb, yCb) denotes the position of the top-left count of the current block, and CbW denotes the width of the current block. The left adjacent blocks may contain at least one of a block A0 containing a sample located at (xCb-1, yCb+CbH), a block A1 containing a sample located at (xCb-1, yCb+CbH-1), and a block A2 containing the sample located at (xCb-1, yCb). Here CbH denotes the height of the current block.

[00442] A temporally adjacent block may contain at least one of a block C0 containing a sample at the center of the block having the same position and size as the current block in the adjacent block, and a block C1 containing a sample adjacent to the bottom right corner of the block.

[00443] The maximum number of motion vector prediction candidates that can contain the motion vector prediction candidate list can be two. The sequence for obtaining motion vector prediction candidates is as described below.

[00444] 1. When at least one of the left neighbor block A0 and the left neighbor block A1 is available, the motion vector of the available block is set as a motion vector prediction candidate.

[00445] 2. When at least one of the upper neighboring block B0, the upper neighboring block B1 and the upper neighboring block B2 is available, the motion vector of the available block is set as a motion vector prediction candidate.

[00446] 3. When a temporally adjacent block is available, a temporal motion vector is set as a motion vector prediction candidate.

[00447] 4. The zero motion vector is set as a motion vector prediction candidate.

[00448] Alternatively, when the number of motion vector prediction candidates obtained in the sequence 1 to 3 is less than two, the motion vector included in the inter-section motion information list may be set as the motion vector prediction candidate. When a list of inter-section motion information is available, motion vector prediction candidates can be obtained in the sequence described below.

[00449] 1. When at least one of the left neighbor block A0 and the left neighbor block A1 is available, the motion vector of the available block is set as a motion vector prediction candidate.

[00450] 2. When at least one of the upper neighboring block B0, the upper neighboring block B1 and the upper neighboring block B2 is available, the motion vector of the available block is set as a motion vector prediction candidate.

[00451] 3. When a temporally adjacent block is available, a temporal motion vector is set as a motion vector prediction candidate.

[00452] 4. A motion vector included in the inter-section motion information list is set as a motion vector prediction candidate.

[00453] 5. The zero motion vector is set as a motion vector prediction candidate.

[00454] A motion vector prediction candidate having a motion vector obtained by adding an offset vector to or subtracting from a motion vector of the reference motion vector prediction candidate may be added to the motion vector prediction candidate list. A motion vector prediction candidate having a motion vector obtained by adding an offset vector to or subtracting from a motion vector of a reference motion vector prediction candidate may be called a refined motion vector prediction candidate.

[00455] In FIG. 37 is a view showing motion vector candidates that can be set as a refined motion vector prediction candidate.

[00456] When the motion vector of the reference motion vector prediction candidate is (MvpLX[0], MvpLX[1]), the motion vector of the refined motion vector prediction candidate can be obtained by adding an offset to at least one of the x component and the y component of the motion vector candidate for predicting or subtracting support vector motion. For example, the motion vector of the refined motion vector prediction candidate can be set as (MvpLX[0]+M, MvpLX[1]), (MvpLX[0]-M, MvpLX[1]), (MvpLX[0], MvpLX[1 ]+M) or (MvpLX[0], MvpLX[1]-M). M denotes the magnitude of the displacement vector.

[00457] The magnitude M of the offset vector may be preset in the encoder and decoder. For example, the magnitude M of the bias vector can be set to an integer that is less than or equal to 4, such as 1 or 4.

[00458] Alternatively, information for determining the offset vector may be transmitted via a bit stream. Information can be transferred at the sequence, image, slice or block level. For example, the displacement vector may be determined using at least one of distance_idx information for determining the magnitude of the displacement vector and direction_idx information for determining the direction of the displacement vector, as described above.

[00459] The reference motion vector prediction candidate may be a motion vector prediction candidate having a predetermined index value in the motion vector prediction candidate list. For example, from the motion vector prediction candidates included in the motion vector prediction candidate list, the motion vector prediction candidate having an index value of 0 or the motion vector prediction candidate having an index value of 1 may be set as the reference motion vector prediction candidate .

[00460] As another example, an offset vector may be determined using a merge refinement offset list containing at least one prediction vector offset candidate. When the motion vector prediction candidate indicated by the current block index information is a reference motion vector prediction candidate, the offset vector can be determined using the prediction vector refinement offset list. In addition, the motion prediction vector of the current block can be obtained by adding or subtracting an offset vector to or subtracting the motion vector prediction candidate motion vector. The reference motion vector prediction candidate may be a motion vector prediction candidate having a predetermined index value in the motion vector prediction candidate list. For example, among the motion vector prediction candidates included in the motion vector prediction candidate list, the motion vector prediction candidate having the smallest index value or the motion vector prediction candidate having the largest index value may be set as the reference motion vector prediction candidate.

[00461] When an offset vector is calculated using a prediction vector offset refinement list, the maximum number of candidate prediction vectors that can contain the candidate prediction vector list can be set to a value that is greater than 2.

[00462] In FIG. 38 is a view showing a configuration of an offset list with prediction vector refinement.

[00463] As shown in FIG. 38, it is assumed that the prediction candidate reference vector is a prediction candidate vector having an index of 2.

[00464] When the index of the prediction candidate vector indicated by the index information AMVPcand_idx indicating any of the prediction candidate vectors is not 2, the motion vector of the prediction candidate vector can be set as the motion prediction vector of the current block.

[00465] On the other hand, when the index of the candidate prediction vector specified by the index information AMVPcand_idx is 2, the offset vector can be obtained using the offset list with prediction vector refinement. Index information AMVPOffset_idx indicating any of the prediction vector offset candidates included in the prediction vector refinement offset list may be transmitted via a bit stream.

[00466] When an offset vector is specified, the motion prediction vector of the current block can be obtained by adding the offset vector to or subtracting from the motion vector of the candidate reference prediction vector.

[00467] Even when a coding block is encoded based on an affine motion model, a motion vector refinement method can be used. For example, when the advanced affine motion vector prediction mode is applied, the affine source vectors of the encoding block can be obtained by adding the difference affine source vector to the affine prediction source vector. Here, the affine source vector of the prediction can be obtained based on the affine source vector of the spatially adjacent block or the temporally adjacent block of the encoding block. The affine source difference vector can be determined based on the information transmitted from the bitstream. In this case, the same affine source difference vector can be applied to all control points. Alternatively, information to determine the affine source vector may be transmitted for each reference point.

[00468] When an affine vector for a sub-block is obtained based on the affine source vectors of the encoding block, the affine vector can be set as an initial motion vector, and then a displacement vector can be obtained. The motion vector of each sub-block can be obtained by adding or subtracting the displacement vector to the initial motion vector.

[00469] Instead of transmitting information to determine the offset vector, the decoder may receive the offset vector. Specifically, the displacement vector can be obtained using the average of the horizontal direction gradients and the average of the vertical direction gradients of the prediction samples included in the subblock.

[00470] Intra prediction is designed to predict the current block using reconstructed samples that were encoded/decoded in the vicinity of the current block. In this case, the samples reconstructed before applying the filter in the loop can be used for intra-prediction of the current block.

[00471] The intra prediction method includes matrix-based intra prediction and general intra prediction taking into account directionality relative to neighboring reconstructed samples. Information indicating the intra prediction method of the current block may be transmitted via a bitstream. The information may be a 1-bit flag. Alternatively, the intra prediction method of the current block may be determined based on at least one of the location, size and shape of the current block or based on the intra prediction method of the neighboring block. For example, when the current block is on an image boundary, it may be determined that there is no need to apply matrix-based intra prediction to the current block.

[00472] Intra prediction, which is matrix-based intra prediction, is a method of obtaining a block prediction of a current block by an encoder and decoder based on a matrix product between a previously stored matrix and reconstructed samples in the vicinity of the current block. Information to indicate any of a plurality of previously stored matrices may be transmitted via a bitstream. The decoder may determine a matrix for intra prediction of the current block based on the information and size of the current block.

[00473] General intra prediction is a method of obtaining a prediction block for a current block based on an intra prediction mode not based on angle information or an intra prediction mode based on angle information.

[00474] The resulting residual image can be obtained by subtracting the prediction video from the original video. In this case, when the residual video is changed to the frequency domain, the subjective quality of the video is not significantly reduced although the high-frequency components are removed from the frequency components. Accordingly, when the high-frequency component values are converted to small values or the high-frequency component values are set to 0, the effect of increasing compression efficiency occurs without generating significant visual distortion. Reflecting this characteristic, the current block can be transformed to decompose the residual video into two-dimensional frequency components. The conversion can be done using a transform method such as discrete cosine transform (DCT) or discrete sine transform (DST).

[00475] After converting the current block using DCT or DST, the converted current block can be re-converted. In this case, the transformation based on the DCT or DST can be defined as the first transform, and the retransformation of the block to which the first transform is applied can be defined as the second transform.

[00476] The first transformation may be performed using any of a variety of candidate transformation bases. For example, the first conversion may be performed using any of DCT2, DCT8 or DCT7.

[00477] Different transformation bases may be used for the horizontal direction and the vertical direction. Information indicating a combination of a translation base in the horizontal direction and a transformation basis in the vertical direction may be transmitted by a bit stream.

[00478] The elements for performing the first transformation and the second transformation may be different. For example, the first transformation may be performed on an 8x8 block, and the second transformation may be performed on a 4x4 subblock of the transformed 8x8 block. In this case, the transformation coefficients of the residual areas for which the second transformation has not been performed can be set to 0.

[00479] Alternatively, the first transform may be performed on the 4x4 block and the second transform may be performed on the 8x8 portion containing the transformed 4x4 block.

[00480] Information indicating whether the second conversion has been performed may be transmitted via a bitstream.

[00481] The decoder may inverse the second transform (second inverse transform) and may inverse the first transform (first inverse transform) with respect to the result of the inverse transform. By performing the second deconversion and the first deconversion, residual signals for the current block can be obtained.

[00482] Quantization is designed to reduce the energy of a block, and the quantization process involves the process of dividing the conversion coefficient into a specific constant value. A constant value can be obtained using a quantization parameter, and the quantization parameter can be defined as a value from 1 to 63.

[00483] When the encoder performs the transform and quantization, the decoder can obtain the residual block by inverse quantization and inverse transform. The decoder can obtain a reconstructed block for the current block by adding the prediction block and the residual block.

[00484] When the reconstructed block of the current block is obtained, the information loss occurring in the quantization and encoding process can be reduced by in-loop filtering. The filter in the loop may include at least one of a deblocking filter, an adaptive sample offset filter (SAO), and an adaptive loop filter (ALF).

[00485] The application of the embodiments described above, focused on a decoding process or an encoding process, to an encoding process or a decoding process is included within the scope of the present invention. Changing the embodiments described in a predetermined order in an order different from the described order is also included within the scope of the present invention.

[00486] Although the above embodiments have been described based on a number of steps or flowcharts, this does not limit the timing of the present invention, and they can be performed simultaneously or in a different order as necessary. In addition, each of the components (eg, elements, modules, etc.) constituting the block diagram in the embodiments described above may be implemented as a hardware device or software, or a plurality of components may be combined to be implemented as one hardware device or software. The embodiments described above may be implemented in the form of program instructions that can be executed by various computer components and recorded in a computer-readable storage medium. The computer-readable storage medium may contain program instructions, data files, data structures, and the like. independently or in combination. Computer readable storage media includes, for example, magnetic media such as hard disk, floppy disk and magnetic tape, optical storage media such as CD-ROM and DVD, magnetic-optical media such as floppy optical disk, and hardware devices specially designed with the ability to store and execute software commands, such as ROM, RAM, flash memory, etc. The hardware devices described above may be configured to operate using one or more software modules to perform a process according to the present invention, and vice versa.

[00487] The present invention can be applied to an electronic device that encodes and decodes video.

Claims (38)

1. A method for video decoding, including the following steps: determining whether the merging motion vector difference encoding method is applied to the current block to be decoded; generating a list of merge candidates for the current block; indicating a merge candidate for the current block based on the list of merge candidates; And obtaining a motion vector for the current block based on the merging candidate, wherein when the merging motion vector difference encoding method is applied to the current block, the motion vector of the current block is obtained by adding an offset vector to the motion vector of the merging candidate; wherein, when the maximum number of merge candidates that the merge candidate list can contain is 1, the merge candidate is determined without decoding the index information; And wherein the displacement vector magnitude is determined based on the first index information indicating one of the motion module candidates, and at least one of the maximum value and the minimum value of the motion module candidates is changed according to the change in motion vector precision for the current block. 2. The method according to claim 1, characterized in that at least one of the maximum value and the minimum value of the motion module candidates is changed according to a change in the value of a flag indicating the numerical values of the motion module candidates. 3. The method according to claim 2, characterized in that the flag is transmitted at the image level. 4. The method according to claim 1, characterized in that the displacement vector modulus is obtained by applying a shift operation to the value indicated by the candidate motion modulus indicated by the first index information. 5. Method according to any one of paragraphs. 1-4, characterized in that the direction of the displacement vector is determined based on the second index information indicating one of the vector direction candidates. 6. Video encoding method, including the following steps: determining whether the merging motion vector difference encoding method is applied to the current block to be encoded; generating a list of merge candidates for the current block; indicating a merge candidate for the current block based on the list of merge candidates; And obtaining a motion vector for the current block based on the merging candidate, wherein when the merging motion vector difference encoding method is applied to the current block, the motion vector of the current block is obtained by adding an offset vector to the motion vector of the merging candidate; wherein, when the maximum number of merge candidates that the merge candidate list can contain is 1, encoding of index information is omitted; And wherein the method further includes the step of encoding first index information for indicating a motion module candidate indicating a displacement vector module from a plurality of motion module candidates, wherein at least one of the maximum value and the minimum value of the motion module candidates is changed according to the change in precision motion vector for the current block. 7. The method of claim 6, further comprising the step of encoding a flag indicating numerical values of the motion module candidates, wherein at least one of the maximum value and the minimum value of the motion module candidates is changed according to the change in the value of the flag. 8. The method according to claim 7, characterized in that the flag is encoded at the image level. 9. The method according to claim 6, characterized in that the motion modulus candidate has a value obtained by applying a shift operation to the displacement vector modulus. 10. Method according to any one of paragraphs. 6-9, characterized in that it further includes the step of encoding second index information for indicating a vector direction candidate indicating the direction of an offset vector from a plurality of vector direction candidates. 11. A video decoding apparatus, comprising an inter-picture prediction portion for determining whether a merging motion vector difference encoding method applies to a current block to be decoded, generating a merging candidate list for the current block, indicating a merging candidate for of the current block based on the merging candidate list, and obtaining a motion vector for the current block based on the merging candidate, wherein when the merging motion vector difference encoding method is applied to the current block, the motion vector of the current block is obtained by adding an offset vector to the motion vector of the candidate for merger; wherein, when the maximum number of merge candidates that the merge candidate list can contain is 1, the merge candidate is determined without decoding the index information; And wherein the magnitude of the displacement vector is determined based on the first index information indicating one of the motion module candidates, and at least one of the maximum value and the minimum value of the motion module candidates is changed according to the change in motion vector precision for the current block. 12. The video decoding device according to claim 11, characterized in that at least one of the maximum value and the minimum value of the motion module candidates is changed according to a change in the value of a flag indicating the numerical values of the motion module candidates, and wherein the flag is transmitted at the image level . 13. Video decoding device according to any one of claims. 11 or 12, characterized in that the direction of the displacement vector is determined based on the second index information indicating one of the vector direction candidates. 14. A video encoding apparatus comprising an inter-picture prediction portion for determining whether a merging motion vector difference encoding method applies to a current block to be encoded, generating a merging candidate list for the current block, indicating a merging candidate for of the current block based on the merging candidate list, and obtaining a motion vector for the current block based on the merging candidate, wherein when the merging motion vector difference encoding method is applied to the current block, the motion vector of the current block is obtained by adding an offset vector to the motion vector of the candidate for the merger, wherein, when the maximum number of merge candidates that the merge candidate list can contain is 1, encoding of index information is omitted; And wherein the inter-picture prediction portion is further configured to encode first index information for indicating a motion module candidate indicating a displacement vector module from a plurality of motion module candidates, wherein at least one of a maximum value and a minimum value of the candidates per motion module changes according to the change in the accuracy of the motion vector for the current block. 15. The video encoding apparatus according to claim 14, characterized in that the inter-picture prediction portion is further configured to encode a flag indicating numerical values of motion module candidates, wherein at least one of a maximum value and a minimum value of motion module candidates the motion module changes according to the change in the value of the flag, and the flag is encoded at the image level. 16. Video encoding device according to any one of claims. 14-15, characterized in that the inter-picture prediction portion is further configured to encode second index information for indicating a vector direction candidate indicating a direction of an offset vector from a plurality of vector direction candidates. 17. Video decoder containing: at least one processor; And a storage device storing computer programs that, when executed by at least one processor, cause the at least one processor to execute the method of any one of claims. 1–5. 18. Video encoder containing: at least one processor; And a storage device storing computer programs that, when executed by at least one processor, cause the at least one processor to execute the method of any one of claims. 6-10.