BR122020014034B1 - INTRAPREDICTION METHOD FROM A VIDEO - Google Patents

Abstract

A method and apparatus for intrapredicting a video. The method includes: determining availability of a predetermined number of adjacent pixels used for intraprediction of a current block; if a first adjacent pixel is unavailable, fetching a second adjacent pixel that is available by fetching the predetermined number of adjacent pixels in a predetermined direction based on the first adjacent pixel; and replacing a pixel value of the first adjacent pixel with a pixel value of a found second adjacent pixel. At least a third adjacent pixel at another location, which is unavailable and excludes the first adjacent pixel at a predetermined location, is sequentially replaced using a directly adjacent pixel in a predetermined direction.

Description

Field of invention

[0001] The present invention relates to intraprediction of a video, and more particularly to a method and apparatus for intraprediction of a video, which involves replacing an unavailable adjacent pixel in a limited intraprediction mode that limits a use of a pixel adjacent, and use the replaced adjacent pixel as a reference pixel.

PREVIOUS TECHNIQUE

[0002] In an image compression method, such as Moving Picture Experts Group (MPEG)-1, MPEG-2, MPEG-4, or H.264/MPEG-4 Advanced Video Coding (AVC), a frame is divided into macroblocks for encoding an image. Each of the macroblocks is encoded in all encoding modes that can be used in interprediction or intraprediction, and is then encoded in a encoding mode that is selected according to a bit rate used to encode the macroblock and a degree of distortion between a decoded macroblock and the original macroblock.

[0003] As hardware for playing and storing high-resolution or high-quality video content is being developed and shipped, there is an increasing need for a video codec capable of effectively encoding or decoding high-resolution or high-quality video content. high. In a conventional video codec, a video is encoded into units of macroblocks each having a predetermined size.

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL PROBLEM

[0004] The present invention provides a method of replacing an unavailable adjacent pixel in a limited intraprediction mode that limits the use of an adjacent pixel used in intraprediction.

TECHNICAL SOLUTION

[0005] method for intrapredicting video determines availability of a predetermined number of adjacent pixels used for intraprediction, if an unavailable first adjacent pixel requires, fetches a second adjacent pixel that is available by fetching a predetermined number of adjacent pixels in a predetermined direction with based on the first adjacent pixel, and replaces a pixel value of the first adjacent pixel with a pixel value of a second adjacent pixel found. For an unavailable third adjacent pixel, a replacement process is performed using an adjacent pixel in a predetermined direction.

ADVANTAGEOUS EFFECTS

[0006] In accordance with one or more embodiments of the present invention, the complexity of a process of determining a reference pixel used for intraprediction can be reduced by searching and replacing an available adjacent pixel, based on a predetermined search direction, with an adjacent pixel is unavailable.

DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a block diagram of an apparatus for encoding a video, according to an embodiment of the present invention;

[0008] Figure 2 is a block diagram of an apparatus for decoding a video, according to an embodiment of the present invention;

[0009] Figure 3 is a diagram for describing a concept of coding units according to an embodiment of the present invention;

[00010] Figure 4 is a block diagram of an image encoder based on coding units according to an embodiment of the present invention;

[00011] Figure 5 is a block diagram of an image decoder based on coding units according to an embodiment of the present invention;

[00012] Figure 6 is a diagram illustrating deeper coding units according to depths, and partitions according to an embodiment of the present invention;

[00013] Figure 7 is a diagram for describing a relationship between a coding unit and transformation units, according to an embodiment of the present invention;

[00014] Figure 8 is a diagram for describing coding information of coding units corresponding to a coded depth, in accordance with an embodiment of the present invention;

[00015] Figure 9 is a diagram of deeper coding units according to depths, according to an embodiment of the present invention;

[00016] Figures 10 to 12 are diagrams for describing a relationship between coding units, prediction units, and transformation units, in accordance with an embodiment of the present invention;

[00017] Figure 13 is a diagram for describing a relationship between a coding unit, a prediction unit or a partition, and a transformation unit, in accordance with coding mode information from table 1;

[00018] Figure 14 is a table showing a number of intraprediction modes according to a size of a prediction unit, according to an embodiment of the present invention;

[00019] Figure 15 is a reference diagram for describing intraprediction modes having various directivities, in accordance with an embodiment of the present invention;

[00020] Figure 16 is a diagram for describing a relationship between a current pixel and adjacent pixels arranged in an extension line having a directivity of (dx, dy), in accordance with an embodiment of the present invention;

[00021] Figures 17 and 18 are diagrams showing directions in an intraprediction manner, in accordance with embodiments of the present invention;

[00022] Figure 19 is a diagram showing directions of an intraprediction mode having 33 directivities, according to an embodiment of the present invention;

[00023] Figure 20 is a diagram of an adjacent pixel that is unavailable during intraprediction of a current block according to a type of an adjacent block, according to an embodiment of the present invention;

[00024] Figure 21 is a diagram for describing a process of replacing an unavailable adjacent pixel, in accordance with an embodiment of the present invention;

[00025] Figure 22 is a diagram for describing a process of replacing an unavailable adjacent pixel, according to another embodiment of the present invention;

[00026] Figure 23 is a diagram for describing a process of replacing an unavailable adjacent pixel, in accordance with another embodiment of the present invention;

[00027] Figure 24 is a block diagram of an intraprediction apparatus according to an embodiment of the present invention;

[00028] Figure 25A is a diagram of a filtered adjacent pixel of a current block;

[00029] Figure 25B is a reference diagram for describing a process of filtering an adjacent pixel of a current block;

[00030] Figure 26 is a flowchart illustrating a video intraprediction method, according to an embodiment of the present invention;

[00031] Figure 27A illustrates a physical structure of a disk that stores a program, according to an embodiment of the present invention;

[00032] Figure 27B illustrates a disk unit that writes and reads a program using a disk;

[00033] Figure 28 illustrates an entire structure of a content delivery system that provides a content distribution service;

[00034] Figures 29 and 30 illustrate external and internal structures of a cell phone to which a video coding method and a video decoding method are applied, in accordance with an embodiment of the present invention;

[00035] Figure 31 illustrates a digital broadcasting system that employs a communication system, according to an embodiment of the present invention; It is

[00036] Figure 32 illustrates a network structure of a cloud computing system using a video coding device and a video decoding device, in accordance with an embodiment of the present invention.

Best way

[00037] In accordance with one aspect of the present invention, there is provided a method of intrapredicting a video, the method comprising: determining availability of a predetermined number of adjacent pixels used for intraprediction of a current block between blocks obtained by dividing a frame that forms the video according to a hierarchical structure; if a first adjacent pixel is unavailable in the predetermined number of adjacent pixels, fetching a second adjacent pixel that is available by fetching the predetermined number of adjacent pixels in a predetermined direction based on the first adjacent pixel; replacing a pixel value of the first adjacent pixel with a pixel value of a found second adjacent pixel; and performing intraprediction on the current block using the predetermined number of adjacent pixels comprising the first substituted adjacent pixel.

[00038] Determining availability comprises determining adjacent pixels, which are included in the adjacent block that is interpredicted or which belong to a slice other than a slice to which the current block belongs, as being unavailable.

[00039] first adjacent pixel may be a pixel at a predetermined location among the predetermined number of adjacent pixels, and searching for the second adjacent pixel may comprise determining an available adjacent pixel, which was initially found by searching the predetermined number of adjacent pixels in the predetermined direction based on the first adjacent pixel being the second adjacent pixel.

[00040] first adjacent pixel may be an adjacent pixel located in a top left corner of the current block, and searching for the second adjacent pixel may comprise searching for the second adjacent pixel by searching top right and top right adjacent pixels of the current left block to the right based on the first adjacent pixel, and if a second adjacent pixel is unavailable in the upper right and top adjacent pixels of the current block, fetch lower left and left adjacent pixels of the current block from the top to the part bottom based on the first adjacent pixel.

[00041] first adjacent pixel may be an adjacent pixel located in an upper left corner of the current block, and searching for the second adjacent pixel may comprise searching for the second adjacent pixel by searching lower left and left adjacent pixels of the current block from the top to bottom based on the first adjacent pixel, and if a second adjacent pixel is unavailable to the left of the current block's bottom left adjacent pixels, fetch top right and top right adjacent pixels of the current block from the left to the right based on the first adjacent pixel.

[00042] first adjacent pixel may be an adjacent pixel located in an upper left corner of the current block, and searching for the second adjacent pixel may comprise determining an available left adjacent pixel by searching lower left and left adjacent pixels of the current block from from top to bottom based on the first adjacent pixel, and determining an available top adjacent pixel by fetching adjacent top and top right pixels of the current block from left to right based on the first adjacent pixel; and replacing the pixel value of the first adjacent pixel using an average value of the available left adjacent pixel and available top adjacent pixel.

[00043] first adjacent pixel may be an adjacent pixel located in an upper left corner of the current block, and searching for the second adjacent pixel may comprise determining an available left adjacent pixel by searching lower left and left adjacent pixels of the current block from from top to bottom based on the first adjacent pixel, determine an available top adjacent pixel by fetching adjacent top and top right pixels of the current block from left to right based on the first adjacent pixel, and determine an adjacent pixel , which is closest to the first adjacent pixel among the fetched top and left adjacent pixels, to be the second adjacent pixel.

[00044] first adjacent pixel may be a lower left adjacent pixel between lower left and left adjacent pixels of the current block, and searching for the second adjacent pixel may comprise searching for the second adjacent pixel by searching lower left and left adjacent pixels of the current block from bottom to top based on the first adjacent pixel, and if a second adjacent pixel is unavailable in the left and bottom left adjacent pixels of the current block, fetch adjacent pixels from the top right and top of the current block from left to right.

[00045] first adjacent pixel may be a top-rightmost adjacent pixel between top-right and top-right adjacent pixels of the current block, and searching for the second adjacent pixel may comprise searching for the second adjacent pixel by searching for top-right adjacent pixels and of the current block from right to left based on the first adjacent pixel, and if a second adjacent pixel is unavailable in the top right and top right adjacent pixels of the current block, fetch adjacent pixels from the bottom left and left of the current block. current block from top to bottom.

[00046] method may further comprise if at least one third adjacent pixel is unavailable, replacing a pixel value of at least one third adjacent pixel with a pixel value of a previously searched adjacent pixel based on the predetermined direction.

[00047] first adjacent pixel may be an adjacent pixel located in a top left corner of the current block, and if at least one third adjacent pixel is located in a top left corner of the current block, the method may further comprise sequentially replacing at least one third pixel adjacent from a third adjacent leftmost pixel with an adjacent pixel to the left of at least one third adjacent pixel, and if at least one third adjacent pixel is located to the left of the current block, sequentially replace at least one third adjacent pixel from a third uppermost adjacent pixel with an adjacent pixel above at least one third adjacent pixel.

[00048] first adjacent pixel may be an adjacent pixel located in a lower left corner of the current block, and if at least one third adjacent pixel is located to the left of the current block, the method may further comprise sequentially replacing at least one third pixel adjacent from a lower third adjacent pixel with an adjacent pixel below at least one third adjacent pixel, and if at least one third adjacent pixel is located at a top of the current block, sequentially replace at least one third adjacent pixel from of a third leftmost adjacent pixel with an adjacent pixel to the left of at least a third adjacent pixel.

[00049] first adjacent pixel may be an adjacent pixel located in a top rightmost corner of the current block, and if at least one third adjacent pixel is located in a top right corner of the current block, the method may further comprise sequentially replacing at least one third adjacent pixel from a rightmost adjacent third pixel with an adjacent pixel to the right of at least one third adjacent pixel, and if at least one third adjacent pixel is located to the left of the current block, sequentially replace at least one third adjacent pixel adjacent from a third uppermost adjacent pixel with an adjacent pixel above at least one third adjacent pixel.

[00050] method may further comprise replacing the pixel value of the first adjacent pixel with a predetermined value if the second adjacent pixel does not exist in the predetermined number of adjacent pixels.

[00051] predetermined value can be determined based on a bit depth of a pixel.

[00052] According to another aspect of the present invention, an apparatus for intrapredicting a video is provided, the apparatus comprising: an availability determiner for determining availability of a predetermined number of adjacent pixels used for intrapredicting a current block between blocks obtained by dividing a frame forming the video according to a hierarchical structure; a replacement means for, if a first adjacent pixel is unavailable in the predetermined number of adjacent pixels, fetching a second adjacent pixel that is available by fetching the predetermined number of adjacent pixels in a predetermined direction based on the first adjacent pixel, and replacing a pixel value of the first adjacent pixel with a pixel value of a second adjacent pixel found; and an intraprediction execution means for performing intraprediction on the current block using the predetermined number of adjacent pixels comprising the first substituted adjacent pixel.

DETAILED DESCRIPTION OF THE INVENTION

[00053] In the following, the present invention will be described more fully with reference to the attached drawings, in which exemplary embodiments of the invention are shown.

[00054] Figure 1 is a block diagram of a video coding apparatus 100, in accordance with an embodiment of the present invention.

[00055] video coding apparatus 100 includes a maximum code unit divider 110, a coding unit determiner 120, and an output unit 130.

[00056] maximum coding unit divider 110 can divide a current frame based on a maximum coding unit for the current frame of an image. If the current frame is larger than the maximum coding unit, image data of the current frame may be divided into at least one maximum coding unit. The maximum coding unit according to an embodiment of the present invention may be a data unit having a size of 32x32, 64x64, 128x128, 256x256, etc., wherein a format of the data unit is a square having a width and length in squares of 2. Image data may be transmitted to the coding unit determiner 120 according to at least one maximum coding unit.

[00057] A coding unit according to an embodiment of the present invention can be characterized by a maximum depth and size. The depth indicates a number of times the coding unit is spatially divided from the maximum coding unit, and as the depth deepens, deeper coding units according to the depths can be divided from the maximum coding unit. maximum encoding in a minimum encoding unit. A maximum coding unit depth is a higher depth and a minimum coding unit depth is a lower depth. Since a size of a coding unit corresponding to each depth decreases as the depth of the maximum coding unit deepens, a coding unit corresponding to a higher depth may include a plurality of coding units corresponding to lower depths.

[00058] As described above, the image data of the current frame is divided into the maximum coding units according to a maximum coding unit size, and each of the maximum coding units may include deeper coding units that are divided accordingly. depending on the depths. Since the maximum coding unit according to an embodiment of the present invention is divided according to depths, image data of a spatial domain included in the maximum coding unit can be hierarchically classified according to depths.

[00059] A maximum depth and a maximum size of a coding unit, which limit the total number of times a height and a width of the maximum coding unit are hierarchically divided can be predetermined.

[00060] The coding unit determiner 120 encodes at least one divided region obtained by dividing a region of the maximum coding unit according to depths, and determines a depth for transmitting finely coded image data according to at least one region divided. In other words, the coding unit determiner 120 determines a coded depth by coding the image data into the deepest coding units according to the depths, according to the maximum coding unit of the current frame, and selecting a depth having the minimum coding error. The determined coded depth and image data coded according to the determined coded depth are transmitted to the output unit 130.

[00061] The image data in the maximum coding unit is encoded based on the deepest coding units corresponding to at least a depth equal to or below the maximum depth, and results of encoding the image data are compared based on each of the deepest coding units. A depth having the minimum coding error can be selected after comparing coding errors of the deepest coding units. At least one encoded depth can be selected for each maximum encoding unit.

[00062] maximum coding unit size is divided as a coding unit is hierarchically divided according to depths, and as the number of coding units increases. Furthermore, even if coding units correspond to the same depth at a maximum coding unit, it is determined whether to divide each of the coding units corresponding to the same depth into a lower depth by measuring a coding error of the image data of each encoding unit, separately. Therefore, even when image data is included in a maximum coding unit, coding errors may differ according to regions in a maximum coding unit, and thus encoded depths may differ according to regions in the image data. . Thereby, one or more coded depths can be determined in a maximum coding unit, and the image data of the maximum coding unit can be divided according to coding units of at least one coded depth.

[00063] Therefore, the coding unit determiner 120 can determine coding units having a tree structure included in the maximum coding unit. The 'coding units having a tree structure' according to an embodiment of the present invention include coding units corresponding to a depth determined to be the coded depth, from among all the deepest coding units included in the coding unit maximum. A coding unit of a coded depth can be hierarchically determined according to depths in the same region as the maximum coding unit, and can be independently determined in different regions. Similarly, a depth encoded in a current region can be independently determined from a depth encoded in another region.

[00064] A maximum depth according to an embodiment of the present invention is an index related to the number of division times from a maximum coding unit to a minimum coding unit. A first maximum depth according to an embodiment of the present invention may indicate the total number of division times from the maximum coding unit to the minimum coding unit. A second maximum depth according to an embodiment of the present invention may indicate the total number of depth levels from the maximum coding unit to the minimum coding unit. For example, when a maximum coding unit depth is 0, a coding unit depth in which the maximum coding unit is divided once can be set to 1, and a coding unit depth in which the maximum coding unit is divided twice, can be set to 2. Here, if the minimum coding unit is a coding unit in which the maximum coding unit is divided four times, 5 depth levels of depths 0, 1, 2, 3, and 4 exist, and so the first maximum depth can be set to 4, and the second maximum depth can be set to 5.

[00065] Prediction coding and transformation can be performed according to the maximum coding unit. Predictive coding and transformation are also performed based on the deepest coding units according to a depth equal to or depths less than the maximum depth according to the maximum coding unit.

[00066] Since the number of deepest coding units increases whenever the maximum coding unit is divided according to depths, coding including prediction coding and transformation is performed on all generated deepest coding units as the depth increases. For convenience of description, prediction coding and transformation will now be described based on a coding unit of a current depth, in a maximum coding unit.

[00067] video encoding apparatus 100 may variously select a size or format of a data unit for encoding the image data. To encode the image data, operations such as prediction coding, transformation and entropy coding are performed, and this time, the same data unit can be used for all operations or different data units can be used for each operation. .

[00068] For example, the video coding apparatus 100 may select not only a coding unit to encode the image data, but also a data unit other than the coding unit in order to perform predictive coding on the image data. image in the encoding unit.

[00069] To perform predictive coding at the maximum coding unit, predictive coding can be performed based on a coding unit corresponding to a coded depth, that is, based on a coding unit that is no longer divided for coding units corresponding to a lower depth. In the following, the coding unit that is no longer divided and becomes a base unit for predictive coding will now be referred to as a ‘predictive unit’. A partition obtained by dividing the prediction unit may include a prediction unit or a data unit obtained by dividing at least one of a height and a width of the prediction unit.

[00070] For example, when a 2Nx2N coding unit (where N is a positive integer) is no longer divided and becomes a 2Nx2N prediction unit, and a partition size can be 2Nx2N, 2NxN, Nx2N or NxN. Examples of a partition type include symmetric partitions that are obtained by symmetrically dividing a prediction unit height or width, partitions obtained by asymmetrically dividing the prediction unit height or width as 1:n or n:1, partitions that are obtained by geometrically dividing the prediction unit, and partitions having arbitrary shapes.

[00071] A prediction mode of the prediction unit can be at least one of an intra mode, an inter mode and a skip mode. For example, intra mode or inter mode can run on the 2Nx2N, 2NxN, Nx2N, or NxN partition. Additionally, skip mode can only be performed on the 2Nx2N partition. coding is independently performed in a prediction unit in a coding unit, thereby selecting a prediction mode having a minimum coding error.

[00072] video coding apparatus 100 may also perform transformation on the image data into a coding unit based not only on the coding unit for encoding the image data, but also based on a data unit that is different from the coding unit.

[00073] To perform the transformation on the coding unit, the transformation can be performed based on a data unit having a size less than or equal to the coding unit. For example, the data unit for the transformation may include a data unit for a mode

[00074] A data unit used as a basis of transformation will now be referred to as a 'transformation unit'. Similar to the coding unit, the transformation unit in the coding unit can be recursively divided into regions of smaller size, so that the transformation unit can be independently determined into region units. In this way, residual data in the coding unit can be divided according to the transformation unit having the tree structure according to transformation depths.

[00075] A transformation depth indicating the number of division times to reach the transformation unit by dividing the height and width of the encoding unit can also be adjusted in the transformation unit. For example, in a current encoding unit of 2Nx2N, a transformation depth may be 0 when the size of a transformation unit is 2Nx2N, may be 1 when the size of the transformation unit is thus NxN, and may be 2 when the size of the transformation unit is therefore N/2xN/2. In other words, the transformation unit having the tree structure can be defined according to the transformation depths.

[00076] Coding information according to coding units corresponding to a coded depth requires not only information about the coded depth, but also information related to prediction and transformation coding. Therefore, the coding unit determiner 120 not only determines a coded depth having a minimum coding error, but also determines a partition type in a prediction unit, a prediction mode according to prediction units, and a size from a processing unit to processing.

[00077] Coding units according to a tree structure in a maximum coding unit and a method of determining a partition, according to embodiments of the present invention, will be described in detail later with reference to figures 3 to 12.

[00078] coding unit determiner 120 can measure a coding error of deeper coding units according to depths using Rate Distortion Optimization based on Lagrangian multipliers.

[00079] The output unit 130 transmits the image data of the maximum coding unit, which is encoded based on at least one coded depth determined by the coding unit determiner 120, and information about the coding mode in accordance with the encoded depth, in bit streams.

[00080] Encoded image data can be obtained by encoding residual data of an image.

[00081] Information about the coding mode according to coded depth may include information about the coded depth, about the type of partition in the prediction unit, prediction mode and the size of the transformation unit.

[00082] Coded depth information can be defined using information divided according to depths, which indicates whether coding is performed in coding units of a lower depth rather than a current depth. If the current depth of the current coding unit is the coded depth, image data in the current coding unit is encoded and transmitted and thereby the split information can be set not to split the current coding unit to a lower depth. Alternatively, if the current depth of the current coding unit is not the coded depth, coding is performed at the coding unit of the lowest depth, and thus the split information can be set to divide the current coding unit to obtain the units coding depth.

[00083] If the current depth is not the encoded depth, encoding is performed in the encoding unit that is divided into the encoding unit of the lowest depth. Since at least one coding unit of the lowest depth exists in a coding unit of the current depth, coding is repeatedly performed on each coding unit of the lowest depth, and thus coding can be recursively performed for the coding units of the lowest depth. encoding having the same depth.

[00084] Since coding units having a tree structure are determined to a maximum coding unit, and information about at least one coding mode is determined to a coding unit of a coded depth, information about at least one encoding mode can be determined for a maximum encoding unit. Furthermore, an encoded depth of the image data of the maximum coding unit may be different according to locations since the image data is hierarchically divided according to depths, and thus information about the encoded depth and the encoding mode can be defined for image data.

[00085] Therefore, the output unit 130 can assign coding information about a corresponding coded depth and a coding mode to at least one of the coding unit, prediction unit and a minimum unit included in the maximum coding unit.

[00086] The minimum unit according to one embodiment of the present invention is a square data unit obtained by dividing the minimum coding unit constituting the lowest depth by 4. Alternatively, the minimum unit may be a maximum square data unit that can be included in all coding units, prediction units, partition units, and transformation units included in the maximum coding unit.

[00087] For example, the coding information transmitted through the output unit 130 can be classified into coding information according to coding units and coding information according to prediction units. The coding information according to the coding units may include information about the prediction mode and the size of the partitions. The coding information according to the prediction units may include information about an estimated direction of an inter mode, about an inter mode reference image index, about a motion vector, about a chroma component of an intra mode, and about an intra mode interpolation method. Additionally, information about a maximum size of the coding unit defined according to frames, slices, or GOPs, and information about a maximum depth may be inserted into a header of a bit stream.

[00088] In the video coding apparatus 100, the deepest coding unit may be a coding unit obtained by dividing a height or width of a coding unit of a higher depth, which is one layer above, by two. In other words, when the coding unit size of the current depth is 2Nx2N, the coding unit size of the lowest depth is NxN. Furthermore, the current depth coding unit having the size of 2Nx2N can include maximum 4 of the lower depth coding unit.

[00089] Therefore, the video coding apparatus 100 can form the coding units having the tree structure by determining coding units having an optimal format and an optimal size for each maximum coding unit, based on the size of the unit. maximum coding depth and the maximum depth determined considering characteristics of the current frame. Furthermore, since coding can be performed on each maximum coding unit using any of several prediction modes and transformations, an optimal coding mode can be determined by considering coding unit characteristics of various image sizes.

[00090] Thus, if an image having high resolution or large amount of data is encoded in a conventional macroblock, a number of macroblocks per frame increases excessively. Therefore, a number of compressed information pieces generated for each macroblock increases, and thus it is difficult to transmit the compressed information and data compression efficiency decreases. However, by utilizing video coding apparatus 100, image compression efficiency can be increased since a coding unit is adjusted while considering characteristics of an image while increasing a maximum size of a coding unit while considering a size of the image.

[00091] Figure 2 is a block diagram of a video decoding apparatus 200, in accordance with an embodiment of the present invention.

[00092] video decoding apparatus 200 includes a receiver 210, a coding information extractor and image data 220, and an image data decoder 230. Definitions of various terms, such as a coding unit, a depth, a prediction unit, a transformation unit, and information about various coding modes, for various operations of the video decoding apparatus 200 are identical to those described with reference to FIG. 1 and the video coding apparatus 100.

[00093] receiver 210 receives and analyzes a bit stream of an encoded video. The coding information and image data extractor 220 extracts coded image data for each coding unit from the analyzed bit stream, wherein the coding units have a tree structure according to each maximum coding unit, and transmits the extracted image data to the image data decoder 230. The encoding information and image data extractor 220 can extract information about a maximum size of a coding unit of a current frame from a header about the current frame.

[00094] Furthermore, the coding information and image data extractor 220 extracts information about a coded depth and a coding mode for the coding units having a tree structure according to each maximum coding unit, from the analyzed bit stream. The extracted information about the encoded depth and encoding mode is transmitted to the image data decoder 230. In other words, the image data in a bit stream is divided into the maximum coding unit so that the data decoder of image 230 decode the image data for each maximum encoding unit.

[00095] Information about the encoded depth and the encoding mode according to the maximum coding unit can be set to information about at least one coding unit corresponding to the encoded depth, and information about a coding mode can include information about a partition type of a corresponding coding unit corresponding to the coded depth, about a prediction mode, and a size of the transformation unit. Furthermore, division information according to depths can be extracted as the encoded depth information.

[00096] Information about the encoded depth and coding mode according to each maximum coding unit extracted by the coding information extractor and image data 220 is information about a coded depth and coding mode determined to generate an error minimum coding unit when an encoder, such as video coding apparatus 100, repeatedly performs coding for each deepest coding unit in accordance with depths in accordance with each maximum coding unit. Therefore, the video decoding apparatus 200 can recover an image by decoding the image data according to a coded depth and a coding mode that generates the minimum coding error.

[00097] Since coding information about the coding depth and coding mode can be assigned to a predetermined data unit among a corresponding coding unit, a prediction unit, and a minimum unit, the coding information extractor and image data 220 can extract information about the encoded depth and encoding mode according to predetermined data units. If information about a coded depth and coding mode of a corresponding maximum coding unit is recorded according to predetermined data units, the predetermined data units to which the same information about the coded depth and coding mode is assigned can be inferred to be the data units included in the same maximum coding unit.

[00098] image data decoder 230 recovers the current frame by decoding the image data into each maximum coding unit based on information about the encoded depth and the coding mode according to the maximum coding units. In other words, the image data decoder 230 can decode the encoded image data based on the extracted information about the partition type, the prediction mode, and the transformation unit for each coding unit among the coding units having the tree structure included in each maximum encoding unit. A decoding process may include a prediction that includes intraprediction and motion compensation, and an inverse transformation.

[00099] The image data decoder 230 may perform intra-prediction or motion compensation according to a partition and a prediction mode of each coding unit, based on information about the partition type and prediction mode of the prediction unit. of the coding unit according to coded depths.

[000100] Furthermore, the image data decoder 230 can perform inverse transformation according to each transformation unit in the coding unit, based on information about the size of the transformation unit of the coding unit according to encoded depths, in order to perform the inverse transformation according to maximum coding units.

[000101] The image data decoder 230 can determine at least one encoded depth from a current maximum coding unit using information divided according to depths. If the split information indicates that the image data is no longer split at the current depth, the current depth is an encoded depth. Therefore, the image data decoder 230 may decode data encoded from at least one coding unit corresponding to each depth encoded in the current maximum coding unit using information about the prediction unit partition type, the prediction mode, and the size of the transformation unit for each encoding unit corresponding to the encoded depth.

[000102] In other words, data units containing the coding information including the same divided information can be collected by observing the set of coding information assigned to the predetermined data unit between the coding unit, the prediction unit, and the minimum unit, and the collected data units can be considered to be a data unit to be decoded by the image data decoder 230 in the same encoding mode.

[000103] Video decoding apparatus 200 may obtain information about at least one coding unit that generates the minimum coding error when coding is recursively performed for each maximum coding unit, and may use the information to decode the current frame . In other words, the coding units having the tree structure determined to be the optimal coding units in each maximum coding unit can be decoded.

[000104] Therefore, even if image data has high resolution and a large amount of data, the image data can be efficiently decoded and recovered by using a size of a coding unit and a coding mode, which are adaptively determined according to characteristics of the image data, using information about an optimal coding mode received from an encoder.

[000105] A method of determining coding units having a tree structure, a prediction unit, and a transformation unit, in accordance with an embodiment of the present invention, will now be described with reference to figures 3 to 13.

[000106] Figure 3 is a diagram for describing a concept of coding units according to an embodiment of the present invention.

[000107] A size of a coding unit can be expressed in width x height, and can be 64x64, 32x32, 16x16 and 8x8. A 64x64 encoding unit can be divided into 64x64, 64x32, 32x64, or 32x32 partitions, and a 32x32 encoding unit can be divided into 32x32, 32x16, 16x32, or 16x16 partitions, a 16x16 encoding unit can be divided into 16x16, 16x8, 8x16, or 8x8 partitions and an 8x8 encoding unit can be divided into 8x8, 8x4, 4x8, or 4x4 partitions.

[000108] In 310 video data, a resolution is 1920x1080, a maximum size of a coding unit is 64, and a maximum depth is 2. In 320 video data, a resolution is 1920x1080, a maximum size of a coding unit is 64, and a maximum depth is 3. In 330 video data, a resolution is 352x288, a maximum size of a coding unit is 16, and a maximum depth is 1. The maximum depth shown in Figure 13 indicates a total number of divisions from a maximum encoding unit to a minimum decoding unit.

[000109] If a resolution is high or an amount of data is large, a maximum size of a coding unit can be large so as to not only increase coding efficiency but also accurately reflect characteristics of an image. Therefore, the maximum coding unit size of video data 310 and 320 having higher resolution than video data 330 may be 64.

[000110] Since the maximum depth of video data 310 is 2, coding units 315 of video data 310 may include a maximum coding unit having a long axis size of 64, and coding units having sizes of long axis of 32 and 16 since the depths are deepened to two layers by dividing the maximum coding unit twice. Meanwhile, since the maximum depth of video data 330 is 1, coding units 335 of video data 330 may include a maximum coding unit having a long axis size of 16, and coding units having a size long axis of 8 since depths are increased for a layer by dividing the maximum coding unit once.

[000111] Since the maximum depth of video data 320 is 3, coding units 325 of video data 320 may include a maximum coding unit having a long axis size of 64, and coding units having sizes of long axis of 32, 16 and 8 since the depths are increased to 3 layers by dividing the maximum encoding unit three times. As depth increases, detailed information can be precisely expressed.

[000112] Figure 4 is a block diagram of an image encoder 400 based on coding units, according to an embodiment of the present invention.

[000113] image encoder 400 performs operations of the coding unit determiner 120 of the video coding apparatus 100 to encode image data. In other words, an intra predictor 410 performs intraprediction in coding units in an intra mode, between a current frame 405, and a motion estimator 420 and a motion compensator 425 perform interestimation and motion compensation in coding units in an intra mode. inter mode between the current frame 405 using the current frame 405, and a reference frame 495.

[000114] Data transmitted from the intra predictor 410, motion estimator 420, and motion compensator 425 is transmitted as a quantized transformation coefficient through a transformer 430 and a quantizer 440. The quantized transformation coefficient is recovered as data in a spatial domain through an inverse quantizer 460 and an inverse transformer 470, and the data recovered in the spatial domain is transmitted as the reference frame 495 after being further processed through an unblocking unit 480 and a loop filtering unit 490 The quantized transformation coefficient may be transmitted as a bit stream 455 through an entropy encoder 450.

[000115] For the image encoder 400 to be applied to the video coding apparatus 100, all elements of the image encoder 400, i.e., the intra predictor 410, the motion estimator 420, the motion compensator 425, the transformer 430, the quantizer 440, the entropy encoder 450, the inverse quantizer 460, the inverse transformer 470, the deblocking unit 480, and the loop filtering unit 490 perform operations based on each coding unit between coding units having a tree structure while considering the maximum depth of each maximum coding unit.

[000116] Specifically, the intra predictor 410, the motion estimator 420, and the motion compensator 425 determine partitions and a prediction mode of each coding unit among the coding units having a tree structure while considering the maximum size and the maximum depth of a current maximum coding unit, and the transformer 430 determines the size of the transformation unit in each coding unit among the coding units having a tree structure.

[000117] Figure 5 is a block diagram of an image decoder 500 based on coding units, according to an embodiment of the present invention.

[000118] An analyzer 510 analyzes encoded image data to be decoded and information about the encoding required for decoding a bit stream 505. The encoded image data is transmitted as inverse quantized data through an entropy decoder 520 and a quantizer inverse 530, and the inverse quantized data is recovered to image data in a spatial domain via an inverse transformer 540.

[000119] An intra predictor 550 performs intraprediction on coding units in an intra mode with respect to image data in the spatial domain, and a motion compensator 560 performs motion compensation on coding units in an inter mode by utilizing a frame of reference 585.

[000120] Image data in the spatial domain, which has passed through the intra predictor 550 and motion compensator 560, can be transmitted as a recovered frame 595 after being further processed through an unblocking unit 570 and a loop filtering unit 580. Furthermore, image data that is further processed through the deblocking unit 570 and the loop filtering unit 580 can be transmitted as the reference frame 585.

[000121] To decode the image data in the image data decoder 230 of the video decoding apparatus 200, the image decoder 500 may perform operations that are performed after the analyzer 510.

[000122] For image decoder 500 to be applied to video decoding apparatus 200, all elements of image decoder 500, i.e., analyzer 510, entropy decoder 520, inverse quantizer 530, inverse transformer 540, intra predictor 550, motion compensator 560, deblocking unit 570, and loop filtering unit 580 perform operations based on coding units having a tree structure for each maximum coding unit.

[000123] Specifically, the intraprediction 550 and the motion compensator 560 perform operations based on partitions and a prediction mode for each of the coding units having a tree structure, and the inverse transformer 540 performs operations based on a size of a transformation unit for each coding unit.

[000124] Figure 6 is a diagram illustrating deeper coding units according to depths, and partitions, according to an embodiment of the present invention.

[000125] video coding apparatus 100 and video decoding apparatus 200 use hierarchical coding units in order to consider characteristics of an image. A maximum height, a maximum width, and a maximum depth of coding units can be adaptively determined according to the characteristics of the image, or can be differently adjusted by a user. The sizes of deeper coding units according to depths can be determined according to the predetermined maximum size of the coding unit.

[000126] In a hierarchical structure 600 of coding units, according to an embodiment of the present invention, the maximum height and maximum width of the coding units are individually 64, and the maximum depth is 4. As a depth increases Along a vertical geometric axis of the hierarchical structure 600, a height and a width of the deepest coding unit are individually divided. Furthermore, a prediction unit and partitions, which are bases for predictive coding of each deeper coding unit, are shown along a horizontal geometric axis of the hierarchical structure 600.

[000127] In other words, a coding unit 610 is a maximum coding unit in the hierarchical structure 600, where a depth is 0 and a size, that is, a height by width, is 64x64. Depth increases along the vertical axis, and an encoding unit 620 having a size of 32x32 and a depth of 1, an encoding unit 630 having a size of 16x16 and a depth of 2, an encoding unit 640 having a size of 8x8 and a depth of 3, and a 650 encoding unit having a size of 4x4 and a depth of 4 exist. The coding unit 650 having the size of 4x4 and the depth of 4 is a minimum coding unit.

[000128] The prediction unit and the partitions of a coding unit are arranged along the horizontal geometric axis according to each depth. In other words, if the coding unit 610 having the size of 64x64 and the depth of 0 is a prediction unit, the prediction unit can be divided into partitions included in the coding unit 610, that is, a partition 610 having a size of 64x64, 612 partitions having the size of 64x32, 614 partitions having the size of 32x64, or 616 partitions having the size of 32x32.

[000129] Similarly, a prediction unit of the coding unit 620 having the size of 32x32 and the depth of 1 can be divided into partitions included in the coding unit 620, that is, a partition 620 having a size of 32x32, partitions 622 having a size of 32x16, 624 partitions having a size of 16x32, and 626 partitions having a size of 16x16.

[000130] Similarly, a prediction unit of the coding unit 630 having the size of 16x16 and the depth of 2 can be divided into partitions included in the coding unit 630, that is, a partition having a size of 16x16 included in the coding unit 630. encoding 630, partitions 632 having a size of 16x8, partitions 634 having a size of 8x16, and partitions 636 having a size of 8x8.

[000131] Similarly, a prediction unit of the coding unit 640 having the size of 8x8 and the depth of 3 can be divided into partitions included in the coding unit 640, that is, a partition having a size of 8x8 included in the coding unit 640. encoding 640, partitions 642 having a size of 8x4, partitions 644 having a size of 4x8, and partitions 646 having a size of 4x4.

[000132] The coding unit 650 having the size of 4x4 and the depth of 4 is the minimum coding unit and a coding unit of the lowest depth. A prediction unit of coding unit 650 is only assigned to a partition having a size of 4x4.

[000133] To determine at least one coded depth of the coding units constituting the maximum coding unit 610, the coding unit determiner 120 of the video coding apparatus 100 performs coding for coding units corresponding to each depth included in the coding unit. maximum encoding 610.

[000134] A number of deeper coding units according to depths including data in the same range and same size increases as the depth increases. For example, four coding units corresponding to a depth of 2 are required to cover data that is included in one coding unit corresponding to a depth of 1. Therefore, to compare results of coding the same data according to depths, the coding unit corresponding to depth 1 and four coding units corresponding to depth 2 are individually coded.

[000135] To perform encoding for a current depth between depths, a minimum encoding error can be selected for the current depth by performing encoding for each prediction unit in the encoding units corresponding to the current depth, along the horizontal geometric axis of the depth. hierarchical structure 600. Alternatively, the minimum coding error can be sought by comparing the minimum coding errors according to the depths, by performing coding for each depth as the depth increases along the vertical geometric axis of the hierarchical structure 600. A depth and a partition having the minimum coding error in the coding unit 610 may be selected as the coding depth and a partition type of the coding unit 610.

[000136] Figure 7 is a diagram for describing a relationship between a coding unit 710 and transformation units 720, according to an embodiment of the present invention.

[000137] video coding apparatus 100 or video decoding apparatus 200 encodes or decodes an image according to coding units having sizes less than or equal to a maximum coding unit for each maximum coding unit. Transformation unit sizes for transformation during encoding can be selected based on data units that are not larger than a corresponding encoding unit.

[000138] For example, in video coding apparatus 100 or video decoding apparatus 200, if a size of coding unit 710 is 64x64, transformation can be performed using transformation units 720 having a size of 32x32.

[000139] Furthermore, data from the coding unit 710 having the size of 64x64 can be encoded by performing the transformation in each of the transformation units having the size of 32x32, 16x16, 8x8 and 4x4, which are smaller than 64x64 and then a transformation unit having the minimum coding error can be selected.

[000140] Figure 8 is a diagram for describing coding information of coding units corresponding to a coded depth, in accordance with an embodiment of the present invention.

[000141] The output unit 130 of the video coding apparatus 100 may encode and transmit information 800 about a partition type, information 810 about a prediction mode, and information 820 about a size of a transformation unit for each coding unit. corresponding to an encoded depth, such as information about an encoding mode.

[000142] Information 800 indicates information about a format of a partition obtained by dividing a prediction unit from a current coding unit, wherein the partition is a data unit for coding by predicting the current coding unit. For example, a current coding unit CU_O having a size of 2Nx2N can be divided into any of a partition 802 having a size of 2Nx2N, a partition 804 having a size of 2NxN, a partition 806 having a size of Nx2N, and a 808 partition having a size of NxN. Here, information 800 about a partition type is defined to indicate one of the partition 804 having a size of 2NxN, the partition 806 having a size of Nx2N, and the partition 808 having a size of NxN.

[000143] Information 810 indicates a prediction mode for each partition. For example, information 810 may indicate a predictive coding mode performed on a partition indicated by information 800, i.e., an intra mode 812, an inter mode 814, or a skip mode 816.

[000144] Information 820 indicates a transformation unit to be based on when the transformation is performed on a current encoding unit. For example, the transformation unit may be a first intra transformation unit 822, a second intra transformation unit 824, a first inter transformation unit 826, or a second intra transformation unit 828.

[000145] encoding information extractor and image data 220 from video decoding apparatus 200 can extract and use information 800, 810 and 820 for decoding, according to each deeper coding unit.

[000146] Figure 9 is a diagram of deeper coding units according to depths, according to an embodiment of the present invention.

[000147] Split information can be used to indicate a change in depth. Split information indicates whether a coding unit of a current depth is split into coding units of a lower depth.

[000148] A prediction unit 910 for predictive coding of a coding unit 900 having a depth of 0 and a size of 2N_0x2N_0 may include partitions of a partition type 912 having a size of 2N_0x2N_0, a partition type 914 having a size of 2N_0xN_0, a partition type 916 having a size of N_0x2N_0, and a partition type 918 having a size of N_0xN_0. Figure 9 only illustrates the partition types 912 to 918 that are obtained by symmetrically dividing the prediction unit 910, but a partition type is not limited thereto and the partitions of the prediction unit 910 may include asymmetric partitions, partitions having a predetermined format, and partitions having a geometric shape.

[000149] Predictive coding is repeatedly performed on one partition having a size of 2N_0xN_0, two partitions having a size of N_0x2N_0, and four partitions having a size of N_0xN_0, according to each partition type. Predictive coding in an intra mode and an inter mode can be performed on partitions having the sizes of 2N_0x2N_0, N_0x2N_0, 2N_0xN_0, and N_0xN_0. Predictive coding in a skip mode is performed only on the partition having the size of 2N_0x2N_0.

[000150] If a coding error is minor in one of the partition types 912 through 916, the prediction unit 910 may not be partitioned to a lower depth.

[000151] If the encoding error is the smallest in partition type 918, a depth is changed from 0 to 1 to divide partition type 918 into operation 920, and encoding is repeatedly performed in encoding units 930 having a depth of 2 and a size of N_0xN_0 to seek minimum coding error.

[000152] A prediction unit 940 for predictive coding of the coding unit 930 having a depth of 1 and a size of 2N_1x2N_1 (=N_0xN_0) may include partitions of a partition type 942 having a size of 2N_1x2N_1, a partition type 944 having a size of 2N_1xN_1, a partition type 946 having a size of N_1x2N_1, and a partition type 948 having a size of N_1xN_1.

[000153] If a coding error is the smallest in partition type 948, a depth is changed from 1 to 2 to divide partition type 948 into operation 950, and coding is repeatedly performed in coding units 960, which have a depth of 2 and a size of N_2xN_2 to look for a minimum coding error.

[000154] When a maximum depth is d, the operation divided according to each depth can be performed until when a depth becomes d-1, and divided information can be encoded as until when a depth is one from 0 to d-2 . In other words, when coding is performed up to when the depth is d-1 after a coding unit corresponding to a depth of d-2 is divided in operation 970, a prediction unit 990 for coding by predicting a coding unit 980 having a depth of -1 and a size of 2N_(d-1)x2N_(d-1) may include partitions of a partition type 992 having a size of 2N_(d-1)x2N_(d-1), a type of partition type 994 having a size of 2N_(d-1)xN_(d-1), a partition type 996 having a size of N_(d-1)x2N_(d-1), and a partition type 998 having a size of N_(d-1)xN_(d-1).

[000155] Predictive coding can be repeatedly performed on a partition having a size of 2N_(d-1)x2N_(d-1), two partitions having a size of 2N_(d-1)xN_(d-1), two partitions having a size of N_(d-1)x2N_(d-1), four partitions having a size of N_(d-1)xN_(d-1) between partition types 992 through 998 to search for a type of partition having minimal coding error.

[000156] Even when partition type 998 has the minimum coding error, since a maximum depth is d, a CU_(d-1) coding unit having a depth of d-1 is no longer divided into a depth lower, and a coded depth for the coding units constituting a current maximum coding unit 900 is determined to be d-1 and a partition type of the current maximum coding unit 900 may be determined to be N_(d-1)xN_( d-1). Furthermore, since the maximum depth is d and a minimum coding unit 980 having a lower depth of d-1 is no longer split to a lower depth, information split to the coding unit

[000157] A data unit 999 may be a 'minimum unit' for the current maximum coding unit. A minimum unit in accordance with an embodiment of the present invention may be a square data unit obtained by dividing a minimum coding unit 980 by 4. By performing coding repeatedly, the video coding apparatus 100 may select a depth having the error minimum coding by comparing coding errors according to depths of the coding unit 900 to determine a coded depth, and defining a corresponding partition type and a prediction mode as a coding mode of the coded depth.

[000158] As such, the minimum coding errors according to depths are compared at all depths from 1 to d, and a depth having the minimum coding error can be determined as a coded depth. The encoded depth, the prediction unit partition type, and the prediction mode can be encoded and transmitted as information about a coding mode. Furthermore, since a coding unit is divided from a depth of 0 to an encoded depth, only divided information of the encoded depth is set to 0, and divided information of depths excluding the encoded depth is set to 1.

[000159] encoding information extractor and image data 220 from video decoding apparatus 200 may extract and use information about the encoded depth and prediction unit from encoding unit 900 to decode partition 912. The decoding apparatus video device 200 may determine a depth, in which divided information is 0, as a depth encoded using information divided according to depths, and use information about an encoding mode of the corresponding depth for decoding.

[000160] Figures 10 to 12 are diagrams for describing a relationship between coding units 1010, prediction units 1060, and transformation units 1070, in accordance with an embodiment of the present invention.

[000161] Coding units 1010 are coding units having a tree structure, corresponding to coded depths determined by video coding apparatus 100, in a maximum coding unit. The prediction units 1060 are partitions of prediction units of each of the coding units 1010, and the transformation units 1070 are transformation units of each of the coding units 1010.

[000162] When a depth of a maximum coding unit is 0 in coding units 1010, depth of coding units 1012 and 1054 are 1, depths of coding units 1014, 1016, 1018, 1028, 1050, and 1052 are 2 , depths of coding units 1020, 1022, 1024, 1026, 1030, 1032, and 1048 are 3, and depths of coding units 1040, 1042, 1044, and 1046 are 4.

[000163] In prediction units 1060, some coding units 1014, 1016, 1022, 1032, 1048, 1050, 1052, and 1054 are obtained by dividing the coding units into coding units. In other words, partition types in encoding units 1014, 1022, 1050, and 1054 have a size of 2NxN, partition types in encoding units 1016, 1048, and 1052 have a size of Nx2N, and a partition type in encoding unit 1032 has a size of NxN. Prediction units and partitions of the coding units 1010 are less than or equal to each coding unit.

[000164] The transformation or inverse transformation is performed on image data from the coding unit 1052 in the transformation units 1070 into a data unit that is smaller than the coding unit 1052. Additionally, the coding units 1014, 1016 , 1022, 1032, 1048, 1050, and 1052 in the transformation units 1070 are different from those in the prediction units 1060 in terms of sizes and shapes. In other words, video encoding and decoding apparatus 100 and 200 can perform intraprediction, motion estimation, motion compensation, transformation, and inverse transformation individually on a data unit in the same coding unit.

[000165] Therefore, coding is recursively performed in each of the coding units having a hierarchical structure in each region of a maximum coding unit to determine an optimal coding unit, and thereby coding units having a recursive tree structure can be obtained. Coding information may include partition information about a coding unit, information about a partition type, information about a prediction mode, and information about a size of a transformation unit. Table 1 shows the encoding information that can be set by encoding and decoding apparatus 100 and 200. Table 1

[000166] The output unit 130 of the video coding apparatus 100 can transmit the coding information about the coding units having a tree structure, and the coding information and image data extractor 220 of the video decoding apparatus 200 can extract coding information about coding units having a tree structure from a received bit stream.

[000167] Split information indicates whether a current coding unit is split into coding units of a lower depth. If split information of a current depth d is 0, a depth at which a current coding unit is no longer split to a lower depth is an encoded depth, and thus information about a partition type, prediction mode, and a size of a transformation unit can be set to the encoded depth. If the current coding unit is further divided according to the split information, coding is independently carried out into four split coding units of a lower depth.

[000168] A prediction mode can be one of an intra mode, an inter mode, and a skip mode. Intra mode and inter mode can be set on all partition types, and skip mode is set only on a partition type having a size of 2Nx2N.

[000169] The partition type information may indicate symmetric partition types having sizes of 2Nx2N, 2NxN, Nx2N and NxN, which are obtained by symmetrically dividing a height or a width of a prediction unit, and asymmetric partition types having sizes of 2NxnU, 2NxnD, nLx2N and nRx2N, which are obtained by asymmetrically dividing the height or width of the prediction unit. The asymmetric partition types having the sizes of 2NxnU and 2NxnD can be respectively obtained by dividing the height of the prediction unit into 1:3 and 3:1, and the asymmetric partition types having the sizes of nLx2N and nRx2N can be respectively obtained by dividing the width of the prediction unit into 1:3 and 3:1.

[000170] size of the transformation unit can be adjusted to be two types in intra mode and two types in inter mode. In other words, if split information of the transformation unit is 0, the size of the transformation unit can be 2Nx2N, which is the size of the current encoding unit. If divided information of the transformation unit is 1, the transformation units can be obtained by dividing the current encoding unit. Furthermore, if a partition type of the current coding unit having the size of 2Nx2N is a symmetric partition type, a size of a transformation unit may be NxN, and if the partition type of the current coding unit is a type of asymmetric partition the size of the transformation unit can be N/2xN/2.

[000171] Coding information about coding units having a tree structure may include at least one of a coding unit corresponding to a coded depth, a prediction unit, and a minimum unit. The coding unit corresponding to the coded depth may include at least one of a prediction unit and a minimum unit containing the same coding information.

[000172] Therefore, it is determined whether adjacent data units are included in the same coding unit corresponding to the coded depth by comparing coding information of adjacent data units. Furthermore, a corresponding coding unit corresponding to a coded depth is determined using coding information of a data unit, and thereby a distribution of coded depths in a maximum coding unit can be determined.

[000173] Therefore, if a current coding unit is predicted based on coding information from adjacent data units, coding information from data units in deeper coding units adjacent to the current coding unit can be directly referred to and used.

[000174] Alternatively, if a current coding unit is predicted based on coding information from adjacent data units, data units adjacent to the current coding unit are searched using coding information from the data units, and the adjacent coding units queries can be referred to to predict the current coding unit.

[000175] Figure 13 is a diagram for describing a relationship between a coding unit, a prediction unit or a partition, and a transformation unit according to coding mode information from table 1.

[000176] A maximum coding unit 1300 includes coding units 1302, 1304, 1306, 1312, 1314, 1316, and 1318 of coded depths. Here, since the coding unit 1318 is a coding unit of a coded depth, split information can be set to 0. Information about a partition type of the coding unit 1318 having a size of 2Nx2N can be set to be a of a partition type 1322 having a size of 2Nx2N, a partition type 1324 having a size of 2NxN, a partition type 1326 having a size of Nx2N, a partition type 1328 having a size of NxN, a partition type 1332 having a size of 2NxnU, a partition type 1334 having a size of 2NxnD, a partition type 1336 having a size of nLx2N, and a partition type 1338 having a size of nRx2N.

[000177] When the partition type is defined to be symmetric, that is, partition type 1322, 1324, 1326, or 1328, a transformation unit 1342 having a size of 2Nx2N is defined if split information (TU size indicator) of a transformation unit are 0, and a transformation unit 1344 having a size of NxN is defined if a size indicator TU is 1.

[000178] When the partition type is defined to be asymmetric, that is, the partition type 1332, 1334, 1336, or 1338, a transformation unit 1352 having a size of 2Nx2N is defined if a size indicator TU is 0 , and a transformation unit 1354 having a size of N/2xN/2 is defined if a size indicator TU is 1.

[000179] Next, intraprediction performed in a prediction unit by the intra predictor 410 of the video coding apparatus 100 of figure 4 and intra predictor 550 of the video decoding apparatus 200 of figure 5 will be described in detail.

[000180] Intra predictors 410 and 550 perform intraprediction to obtain a prediction value from a current prediction unit using adjacent pixels of the current prediction unit. Considering that a prediction unit has a size equal to or greater than 16x16, the intra predictors 410 and 550 additionally perform an intraprediction mode having multiple directivities using one parameter (dx, dy) as well as an intraprediction model having a limited directivity according to a related technique. The intraprediction mode having multiple directivities according to an embodiment of the present invention will be described later in detail.

[000181] Figure 14 is a table showing a number of intraprediction modes according to a size of a prediction unit, according to an embodiment of the present invention.

[000182] The intra predictors 410 and 550 can variously define the number of intraprediction modes to be applied to the prediction unit according to the size of the prediction unit. For example, with reference to Figure 14, when the size of the prediction unit to be intra-predicted is NxN, the numbers of intra-prediction modes actually performed in the prediction units having the sizes of 2x2, 4x4, 8x8, 16x16, 32x32, 64x64 and 128x128 can be respectively set to 5.9, 9, 17, 33, 5 and 5 in example 2. The number of intraprediction modes actually performed differs according to the size of the prediction unit because overhead for encoding mode information prediction differs according to the size of the prediction unit. In other words, although a portion of a prediction unit that occupies an entire image is small, overhead for transmitting additional information such as a prediction mode from such a small prediction unit can be large. Therefore, when a prediction unit having a small size is encoded in many prediction modes, a number of bits may increase and thus compression efficiency may decrease. Furthermore, since a prediction unit having a large size, for example, a prediction unit having a size equal to or greater than 64x64, is generally generally selected as a prediction unit of a flat region of a image, may be insufficient in terms of compression efficiency to encode the prediction unit having a large size, which is mostly selected to encode a flat region, in many prediction modes. Therefore, when a size of a prediction unit is too large or too small compared to a predetermined size, a relatively small number of intraprediction modes can be applied. However, the number of intraprediction modes applied according to the size of a prediction unit is not limited to Figure 14, and may vary. The number of intraprediction modes applied according to the size of a prediction unit, as shown in figure 14, is just an example, and may vary. Alternatively, the number of intraprediction modes applied to the prediction unit can always be uniform regardless of the size of a prediction unit.

[000183] The intra predictors 410 and 550 may include, with an intraprediction mode applied to a prediction unit, an intraprediction mode that determines an adjacent reference pixel using a line having a predetermined angle based on a pixel in a unit of prediction and using the determined adjacent reference pixel as a predictor of the pixel. The angle of such a line can be defined using a parameter (dx, dy), where dx and dy are individually an integer. For example, when 33 prediction modes are respectively defined to be N modes, where N is an integer from 0 to 32, a mode 0 is defined for a vertical mode, a mode 1 is defined for a horizontal mode, a mode 2 is defined as a DC mode, a 3 mode is defined as a flat mode, and a 32 mode is defined as a flat mode. Furthermore, modes 4 to 31 can be defined as being intraprediction modes determining an adjacent reference pixel using a line having a directivity of tan-1(dy/dx) using (dx, dy) respectively expressed by (1,-1 ), (1,1), (1,2), (2,1), (1,-2), (2,1), (1,-2), (2,-1), (2, -11), (5,-7), (10,-7), (11,3), (4,3), (1,11), (1,-1), (12,-3), (1,-11), (1,-7), (3,-10), (5,-6), (7,-6), (7,-4), (11,1), (6 ,1), (8,3), (5,3), (5,7), (2,7), (5,-7), and (4,-3) from table 1, and using the pixel adjacent reference determined for intraprediction.Table 2

[000184] number of intraprediction modes used by intrapredictors 410 and 550 is not limited to Table 2, and may vary based on whether a current prediction unit is a chrominance component or luminance component or based on a size of the prediction unit. current prediction. Furthermore, each N mode can indicate a different intraprediction mode than the one above. For example, the number of intraprediction modes may be 36, where a mode 0 is a planar mode described later, a mode 1 is a DC mode, modes 2 through 34 are intraprediction modes having 33 directivities as described later, and a mode 35 is an intra_FromLuma intraprediction mode using a prediction unit on a luminance component corresponding to a prediction unit on a chrominance component. Mode 35, that is, the Intra_FromLuma intraprediction mode using the prediction unit in the luminance component corresponding to the prediction unit in the chrominance component, is only applied to the prediction unit in the chrominance component, and is not used to intrapredict the prediction on the luminance component.

[000185] Figure 15 is a reference diagram for describing intraprediction modes having various directivities, in accordance with an embodiment of the present invention.

[000186] As described above, intra predictors 410 and 550 can determine an adjacent reference pixel using a line having an angle of tan-1(dy/dx) determined according to a plurality of parameters (dx, dy), and perform intraprediction using the determined adjacent reference pixel.

[000187] With reference to figure 15, adjacent pixels A and B located on an extension line 150 having an angle of tan- 1(dy/dx) determined according to a value of (dx, dy) according to the modes intraprediction of Table 2 based on a current pixel P to be predicted in a current prediction unit can be used as predictors of the current pixel P. Here, an adjacent pixel used as a predictor can be a pixel from a previous prediction unit that is pre-coded and pre-retrieved and is located above, to the left, top right, or bottom left of a current prediction unit. As such, by performing prediction coding according to intraprediction modes having various directivities, compression can be effectively performed according to characteristics of an image.

[000188] In Figure 15, when a predictor of the current pixel p is generated using an adjacent pixel located at or near extension line 150, extension line 150 actually has a directivity of tan-1(dy/dx) and a division of (dy/dx) is necessary to determine the adjacent pixel using extension line 150, and thus hardware or software may include a decimal point operation, thereby increasing transmission capacity. Therefore, when a prediction direction for selecting a reference pixel is defined using parameters (dx, dy), dx and dy can be defined to decrease a transmission capacity.

[000189] Figure 16 is a diagram for describing a relationship between a current pixel and adjacent pixels arranged in an extension line having a directivity of (dx, dy), in accordance with an embodiment of the present invention.

[000190] With reference to figure 16, P 1610 indicates the current pixel located at (j, i) and A 1611 and B 1612 respectively indicate an adjacent top pixel and an adjacent left pixel located on an extension line having a directivity, i.e. is, an angle of tan-1(dy/dx) passing through the current pixel P 1610. It is assumed that a size of a prediction unit that includes the current pixel P 1610 is nSxnS where ns is a positive integer, a prediction unit pixel location is one of (0, 0) to (nS-1, nS-1), an adjacent top pixel location A 1611 and an x axis is (m, -1) where m is an integer, and a location of the adjacent left pixel B 1612 on a y axis is (-1, n) where n is an integer. The location of the adjacent top pixel A 1611 meeting the extension line passing through the current pixel P1610 is (j+i*dx/dy, -1), and the location of the adjacent left pixel B 1612 is (-1, i+j *dy/dx). Therefore, to determine the adjacent top pixel A 1611 or adjacent left pixel B 1612 to predict the current pixel P1610, a division operation such as dx/dy or dy/dx is required. As described above, since the operation complexity of the division operation is high, an operation speed in software or hardware may be low. Therefore, at least one of dx and dy indicating a directivity of a prediction mode to determine an adjacent pixel may be a power of 2. In other words, when n and m are individually an integer, dx and dy may respectively be 2An and 2am.

[000191] When the adjacent left pixel B 1612 is used as a predictor of the current pixel P 1610 and dx has a value of 2An, a j*dy/dx operation required to determine (-1, i+j*dy/dx) , i.e. a location of the adjacent left pixel B 1612, can be (i*dy)/(2An) and a division operation using a power of 2 can be performed through a switching operation, such as (i*dy)> >n, and thus a transmission capacity is decreased.

[000192] Similarly, when the adjacent top pixel A 1611 is used as a predictor of the current pixel P 1610 and dy has a value of 2Am, an i*dx/dy operation required to determine (j+i*dx/dy,- 1), that is, an adjacent upper pixel location A 1611 may be (i*dx)/(2Am) and a division operation using a power of 2 may be performed through a switching operation such as (i*dx )>>m.

[000193] Figures 17 and 18 are diagrams showing directions in an intrapredictive manner, in accordance with embodiments of the present invention.

[000194] Generally, straight line patterns shown in a video signal or image are mostly vertical or horizontal. Thus, when an intraprediction mode having multiple directivities is defined using a parameter (dx, dy), the values of dx and dy can be defined as follows to improve the coding efficiency of an image.

[000195] In detail, when dy has a fixed value of 2Am, an absolute value of dx can be defined such that a gap between prediction directions close to a vertical direction is narrow and a gap between prediction modes increases toward to a prediction direction close to a horizontal direction. For example, with reference to figure 17, when dy is 2A5, that is, 32, dx can be set to 2, 5, 9,13, 17, 21, 26, 32, -2, -5, -9, - 13, -17, -21, -26, and -32 such that a gap between prediction directions close to a vertical direction is relatively narrow and a gap between prediction modes increases toward a prediction direction close to a vertical direction. horizontal direction.

[000196] Similarly, when dx has a fixed value of 2An, an absolute value of dy can be defined such that a gap between prediction directions close to a horizontal direction is narrow and a gap between prediction modes increases towards a prediction direction close to a horizontal direction. For example, with reference to figure 18, when dx is 2A5, that is, 32, dy can be set to 2, 5, 9, 13, 17, 21, 26, 32, -2, -5, -9, - 13, -17, -21, -26, and -32 such that a gap between prediction directions close to a horizontal direction is relatively narrow and a gap between prediction modes increases towards a prediction direction close to a horizontal direction. vertical direction.

[000197] Furthermore, when one of the values of dx and dy is fixed, the other value can be set to increase according to prediction modes. For example, when the value of dy is fixed, an interval between values of dx can be set to increase by a predetermined amount. Such an increment can be defined according to angles divided between a horizontal direction and a vertical direction. For example, when dy is fixed, dx may have an increment a in a section where an angle with a vertical axis is less than 15°, an increment b in a section where the angle is between 15° and 30°, and an increment c in a section where the angle is greater than 30°.

[000198] For example, prediction modes having directivities of tan-1(dy/dx) using (dx, dy) can be defined by parameters (dx, dy) shown in tables 3 to 5. Table 3 Table 4 Table 5

[000199] As described above, intraprediction modes using parameters (dx, dy) use the adjacent left pixel (-1,i+j*dy/dx) or the adjacent top pixel (j+i*dx/dy,-1 ) as a predictor of a pixel located at (j,i). When at least one of dx and dy has a power of 2 as shown in Table 2, locations of the left pixel (-1, i+j*dy/dx) and adjacent top pixel (j+i*dx/dy,-1 ) can be obtained through multiplication and commutation operations without a division operation. When dx is 2An, that is, 32, in (dx, dy) as shown in table 2, a division operation using dx can be replaced by a right switching operation, and thus a location of an adjacent left pixel can be obtained without a division operation based on (i*dy)>>n. Similarly, when dy is 2Am, that is, 32, in (dx, dy) as shown in table 2, a division operation using dx can be replaced by a right switching operation, and thereby a location of an adjacent upper pixel can be obtained without a division operation based on (i*dx)>>m.

[000200] Figure 19 is a diagram showing directions of an intraprediction mode having 33 directivities, in accordance with an embodiment of the present invention.

[000201] Intra predictors 410 and 550 may determine an adjacent pixel to be used as a predictor of a current pixel in accordance with intraprediction modes having 33 directivities shown in Figure 19. As described above, directions of intraprediction modes may be defined in such a way. such that an interval between prediction modes decreases towards a horizontal or vertical direction and further increases from a vertical or horizontal direction.

[000202] Meanwhile, the use of adjacent pixels used as reference pixels of a current block may be limited according to intraprediction modes having various directivities as described with reference to Figure 19. For example, the use of an adjacent pixel included in an inter-block predicted through inter-prediction may be limited during intra-prediction of the current block. As such, the use of the adjacent pixel included in the inter block is limited so as to prevent propagation of an error included in the inter block. Furthermore, the use of an adjacent block included in a different slice than the current block that is intrapredicted may be limited during intraprediction of the current block. The use of the adjacent block included in the different slice is limited because the use of data from the adjacent block included in the different tape may be limited as reference data of the current block since image data is encapsulated and independently processed in a single slice unit. according to a general image process. Therefore, intra predictors 410 and 550 can determine whether to use an adjacent pixel for intraprediction of the current block based on a prediction mode of an adjacent block including the adjacent pixel or based on whether a slice including the adjacent block is equal to a slice including the current block. The intra predictor 410 of the image encoder 400 may set a value of an indicator (constrained_intra_pred_flag) indicating whether to use an adjacent pixel included in an inter block for intraprediction of a current block, and then add the constrained_intra_pred_flag to an encoded bitstream of in order to signal a limitation on the use of the adjacent pixel included in the inter block. For example, when the value of constrained_intra_pred_flag is 0, the adjacent pixel is used for intraprediction of the current block regardless of a prediction mode of an adjacent block. When the value of constrained_intra_pred_ flag is 1, the adjacent pixel included in the inter block can be constrained during the intraprediction of the current block. Alternatively, intra predictors 410 and 550 may limit a pixel from an adjacent block included in a slice other than that of the current block to never be used for the intraprediction of the current block.

[000203] Next, assuming that the value of constrained_intra_pred_flag is 1, that is, the use of the adjacent block included in the inter block as a reference pixel is limited during the intraprediction of the current block, a process of the intra predictors 410 and 550 replacing an adjacent pixel having limited use as a reference pixel with another adjacent pixel is described in detail with reference to figures 20 to 26. Furthermore, it is assumed that the use of the pixel of the adjacent block included in the slice other than that of the current block is always limited during the intraprediction of the current block.

[000204] Figure 24 is a block diagram of an intraprediction apparatus 2400 according to an embodiment of the present invention. The intraprediction apparatus 2400 of Figure 24 corresponds to the intrapredictors 410 and 550 of Figures 4 and 5.

[000205] Referring to Figure 24, the intraprediction apparatus 2400 includes an availability determiner 2410, a replacement means 2420, and an intraprediction execution means 2430.

[000206] Availability determiner 2410 determines availability of a predetermined number of adjacent pixels used for intraprediction of a current block. here, availability indicates whether an adjacent pixel is usable for intraprediction as a reference pixel of the current block. As described above, once the value of constrained_intra_pred_flag is assumed to be 1, it is determined that an adjacent pixel included in an adjacent block included in a slice other than a slice including the current block or an intra-predicted adjacent block is not available . Accordingly, the availability determiner 2410 determines whether the predetermined number of adjacent pixels of the current block includes the adjacent pixel included in the adjacent block included in the slice other than the slice including the current block or whether the predetermined number of adjacent pixels of the current block includes the adjacent pixel included in inter-predicted adjacent block. The predetermined number of adjacent pixels can be set according to any pattern. For example, when a current block size is nTxnT, where nT is an integer, availability can be determined on a total of 4nT+1 adjacent pixels including 2nT upper adjacent pixels located at the top and upper right of the current block, 2nT left adjacent pixels located to the left and bottom left of the current block and an adjacent pixel located in an upper left corner of the current block. However, the number and locations of adjacent pixels whose availability is determined may vary.

[000207] If the adjacent pixels are all determined to be unavailable, the replacement means 2420 may replace a pixel value of an unavailable adjacent pixel with a predetermined value. Here the default value may be a value determined based on a bit depth of a pixel. Pixel bit depth is a bit number used to express a pixel value of a pixel, and can be 8 to 14 bits. As such, a variable bit depth BitDepth can be represented by an equation; BitDepth=BaseBitDepth+Increased_bit_depth, through a BaseBitDepth base bit depth and a variable increased bit depth increased_bit_depth. If the bit depth is in the range of 8 to 14 bits as described above, the base bit depth BaseBitDepth has a value of 8 and the increased bit depth increased_bit_depth has a value of 0 to 6. If the adjacent pixels are all unavailable, the replacement means 2420 can replace all adjacent pixel values with a value 1<<((BitDepth)-1). For example, when the BitDepth bit depth is 8, the replacement means 2420 can replace all adjacent pixel values to have a pixel value of 1<<(8-1), that is, 128, which is 1x2A7, if the adjacent pixels are all unavailable.

[000208] If it is determined by the availability determiner 2410 that not every predetermined number of adjacent pixels are unavailable, but at least one adjacent pixel is unavailable, the replacement means 2420 searches for an available adjacent pixel by searching the predetermined number of adjacent pixels in a predetermined direction based on the unavailable adjacent pixel, and replaces a pixel value of the unavailable adjacent pixel with a pixel value of a found available adjacent pixel. A process of replacing the unavailable adjacent pixel will be described below with reference to figures 20 to 23.

[000209] When the unavailable adjacent pixel is replaced with the available adjacent pixel, the intraprediction execution means 2430 performs intraprediction on the current block using the replaced adjacent pixel and the available adjacent pixels, and generates a prediction block of the current block.

[000210] In the following, a process of replacing an adjacent pixel not available during intraprediction of a current block will be described in detail with reference to figures 20 to 23.

[000211] Figure 20 is a diagram of an adjacent pixel that is unavailable during intraprediction of a current block 2000 according to a type of an adjacent block, according to an embodiment of the present invention.

[000212] Referring to Figure 20, when a current block size 2000 is nTxnT, the availability determiner 2410 determines whether adjacent blocks A, B, C, D and E including adjacent top 2nT pixels located at the top and upper right of the current block 2000 are interblocks or are blocks included in a different slice from a slice including current block 2000. Additionally, availability determinator 2410 determines whether adjacent blocks G, H, I, J and K including adjacent pixels of the left 2nT located to the left and bottom left of the current block 2000 and an adjacent block F including an adjacent pixel located in an upper left corner of the current block 2000 are interblocks or blocks included in a different slice from the slice including the current block 2000 .

[000213] The availability determiner 2410 determines an adjacent pixel included in an inter block or a block included in the different slice between adjacent blocks A through K as being an unavailable adjacent pixel. In Figure 20, since the adjacent blocks A, B, D, E, F, H and I are inter-predicted blocks, the availability determiner 2410 determines adjacent pixels 2011, 2012 and 2013 included in the adjacent blocks A, B , D, E, F, H and I as adjacent unavailable pixels. As described above, the replacement means 2420 searches for an available adjacent pixel in a predetermined direction based on the unavailable adjacent pixel and replaces a pixel value of the unavailable adjacent pixel with a pixel value of the found available adjacent pixel.

[000214] In detail, the availability determiner 2410 according to one embodiment first determines availability of an adjacent pixel (hereinafter referred to as a first adjacent pixel) at a predetermined location between adjacent pixels. If the first adjacent pixel is not available, the replacement means 2420 searches for a second adjacent pixel that is available by searching for adjacent pixels in a predetermined direction. Furthermore, the replacement means 2420 replaces the first adjacent pixel with the second adjacent pixel found.

[000215] A remaining unavailable adjacent pixel (hereinafter referred to as a third adjacent pixel) excluding the first adjacent pixel is previously processed and replaced based on a predetermined direction or is replaced with an original available adjacent pixel. The unavailable third adjacent pixels are sequentially replaced according to a search order used to search for the second adjacent pixel. When the first adjacent pixel is available, a process of replacing the first adjacent pixel is skipped, and only a process of replacing the third adjacent pixel is performed.

[000216] In the following, it is assumed that current block sizes 2100, 2200 and 2300 of figures 21 through 23 are nTxnT and P(x,y) indicates an adjacent pixel whose availability is determined for intraprediction of current blocks 2100, 2200 and 2300 , where x=-1, y=-1, ..., 2nT-1 and x=0, ..., 2nT-1, y=1.

[000217] Figure 21 is a diagram for describing a process of replacing an unavailable adjacent pixel in accordance with an embodiment of the present invention.

[000218] Referring to Figure 21, a first adjacent pixel whose availability is first determined between adjacent pixels is assumed to be an adjacent pixel P(-1,-1) 2110 located in an upper left corner of the current block 2100. The determiner of availability 2410 first determines availability of the first adjacent pixel P(-1,-1) 2110. If it is determined that the first adjacent pixel P(-1,-1) 2110 is unavailable, the replacement means 2420 searches for an adjacent pixel available in adjacent pixels sequentially according to a predetermined direction based on the first adjacent pixel P(-1,-1) 2110 and replaces the first adjacent pixel P(-1,-1) 2110 with an initially found available adjacent pixel (hereinafter , referred to as a second adjacent pixel). For example, the replacement means 2420 searches top and top right adjacent pixels of the current block 2100 according to a first search direction from left to right based on the first adjacent pixel P(-1,-1) 2110 , and if the second adjacent pixel does not exist in the top right and top adjacent pixels of the current block 2100, fetches the second adjacent block by fetching left and bottom left adjacent pixels of the current block 2100 from the top to the bottom based in the first adjacent pixel P(-1,-1) 2110. The replacement means 2420 replaces the first adjacent pixel P(-1,-1) 2110 with the second adjacent pixel that is initially found according to such search direction and order. For example, if an adjacent pixel P(nT-2, -1) 2120 is the second adjacent pixel that is initially found in the top right and top adjacent pixels, the replacement means 2420 substitutes a pixel value of the first adjacent pixel P(-1,-1) 2110 with a pixel value of the second adjacent pixel P(nT-2, -1) 2120.

[000219] replacement means 2420 replaces the third remaining unavailable adjacent pixel, excluding the first adjacent pixel P(-1,-1) 2110, with an adjacent pixel that is previously processed and replaced based on a predetermined search direction, or an adjacent originally available pixel. For example, the replacement means 2420 replaces the first adjacent pixel P(-1,-1) 2110 with the second adjacent pixel P(nT-2, -1) 2120, and then replaces a next unavailable adjacent pixel P(0, -1), with the first adjacent pixel P(-1,-1) 2110. Since the first adjacent pixel P(-1,-1) 2110 is replaced with the second adjacent pixel P(nT-2, -1 ) 2120, the adjacent pixel P(0,-1) has the same value as the second adjacent pixel P(nT-2, -1) 2120. If the first adjacent pixel P(- 1,-1) 2110 is originally available , a process of replacing the first adjacent pixel P(-1,-1) 2110 is skipped, and thereby the replacement means 2420 replaces the pixel value of the adjacent pixel P(0,-1) with the pixel value of the first adjacent pixel P(-1,-1) 2110. A pixel value from an adjacent pixel P(1, -1) is replaced with a preprocessed pixel value from the adjacent pixel P(0,-1).

[000220] Such replacement process is repeated for all third adjacent unavailable pixels. In figure 21, the second adjacent pixel P(nT-2, -1) 2120 that is available among the top adjacent pixels is not replaced and retains its original pixel value. As such, the replacement means 2420 replaces an unavailable top adjacent pixel with an adjacent pixel that is pre-substituted or an originally available adjacent pixel in accordance with a predetermined search direction. In other words, by deleting the first adjacent pixel P(-1,-1) 2110 and the originally available adjacent pixel, the replacement means 2420 replaces the first adjacent pixel with an adjacent pixel immediately to the left if a search direction is from the left. to the right. As such, when a plurality of third adjacent pixels exists on top of the current block 2100, the replacement means 2420 sequentially replaces the third adjacent left-to-right pixels with a respective left-adjacent pixel. Here, the left adjacent pixel used to replace the third adjacent pixel may be a previously replaced or originally available adjacent pixel. Similarly, the replacement means 2420 replaces the third adjacent pixel that is unavailable among the left and bottom left adjacent pixels of the current block 2100 with an adjacent pixel immediately above. For example, the replacement means 2420 replaces an unavailable adjacent pixel P(-1,0) with the first adjacent pixel P(-1,-1) 2110. As described above, if the first adjacent pixel P(-1,- 1) 2110 is originally available, the process of replacing the first adjacent pixel P(-1,-1) 2110 is skipped, and thereby the replacement means 2420 replaces the adjacent pixel P(-1, 0) with the first adjacent pixel P(-1,-1) 2110. A pixel value from an adjacent pixel P(-1, 1) is replaced with a preprocessed pixel value from the adjacent pixel P(-1, 0). Like the process of replacing the top third adjacent pixels described above, if a plurality of adjacent third pixels exists to the left of the current block 2100, the replacement means 2420 sequentially replaces the top to bottom third adjacent pixels with an adjacent pixel respective top. Here, the top adjacent pixel used to replace the third adjacent pixel may be a pre-replaced or originally available adjacent pixel.

[000221] Such replacement process is repeated for all third left and bottom left adjacent pixels that are unavailable. An adjacent pixel P(-1, nT+1) 2130 available among the adjacent pixels on the left is not replaced, but retains its original pixel value. As such, the replacement means 2420 replaces the left adjacent pixel that is unavailable with a pre-substituted or originally available adjacent pixel in accordance with a predetermined search direction. In other words, if a search direction is from top to bottom, the replacement means 2420 replaces the third adjacent pixel with an adjacent pixel immediately above. Alternatively, if all available adjacent pixels at the top and left of the current block 2100 are searched, the replacement means 2420 may replace the first adjacent pixel P(-1,-1), with an average value of the adjacent pixels found. For example, in Figure 21, a pixel value of the first adjacent pixel P(-1, -1) may be replaced with an average value of the second adjacent pixel P(nT-2,-1) 2120 initially found to be available between the top adjacent pixels and the adjacent pixel P(-1,nT+1) 2130 initially found to be available among the left adjacent pixels. In other words, when PRA indicates a pixel value of the second adjacent pixel P(nT-2, -1) 2120 and PLB indicates a pixel value of the adjacent pixel P(-1, nT+1) 2130, an average value PT obtained through an equation: PT=(PRA + PLB + 1) >>1 can replace the pixel value of the first adjacent pixel P(-1, -1) 2110.

[000222] Alternatively if all adjacent available pixels at the top and left of the current block 2100 are searched, the replacement means 2420 may replace the first adjacent pixel P(-1,-1) 2110 by determining a nearest available adjacent pixel to the first adjacent pixel P(-1,-1) 2110 based on a distance from the first adjacent pixel P(-1,-1) 2110 as the second adjacent pixel, rather than just using the initially found adjacent pixel of according to the predetermined search direction. In figure 21, since a distance between the first adjacent pixel P(-1,-1) 2110 and the second adjacent pixel P(nT-2,-1) 2120 initially found to be available at the top of the current block is ( nT-2)-(-1), i.e., nT-1 and a distance between the first adjacent pixel P(-1,-1) 2110 and the adjacent pixel P(- 1,nT+1) 2130 initially found as being available to the left of the current block 2100 is (nT+1)-(-1), that is, nT+2, the replacement means 2420 can replace the first adjacent pixel P(-1,-1) 2110 with the second adjacent pixel P(nT-2, -1) 2120.

[000223] Alternatively, to reduce complexity of a process of searching for a second adjacent pixel to replace the first adjacent pixel P(-1,-1) 2110, the replacement means 2420 may only search for pixels P(-1,0) and P(0,-1) immediately adjacent to the first adjacent pixel P(-1,-1) 2110 instead of fetching all adjacent pixels to the top and left of the current block 2110, and may replace the first adjacent pixel P(- 1,- 1) 2110 with an adjacent pixel available between pixels P(- 1,0) and P(0,-1). For example, the replacement means 2420 may search for adjacent pixels in an order of pixels P(-1,0) and P(0,-1) or vice versa, and replace the first adjacent pixel P(-1,-1) 2110 with a pixel value from an available adjacent pixel that is found first. If an available adjacent pixel is not found in pixels P(-1,0) and P(0,-1), the replacement means 2420 may replace the first adjacent pixel P(-1,-1) 2110 with a predetermined value based on a bit depth as described above. If both pixels P(-1,0) and P(0,-1) are available, the replacement means 2420 may replace the first adjacent pixel P(-1,-1) 2110 using an average value of the pixels P( -1,0) and P(0,-1).

[000224] Meanwhile, a search order and search direction of the left and top adjacent pixels can be changed. In other words, the replacement means 2420 may first search for pixels adjacent to the left and bottom left of the current block 2100, and if an available adjacent pixel is not found, it may then search for pixels adjacent to the upper and top right. Also, instead of searching for an available adjacent pixel by searching the left and lower left adjacent pixels from the top to the bottom, the replacement means 2420 may search the left and lower left adjacent pixels from the bottom to the top. Furthermore, instead of fetching an available adjacent pixel by fetching the top right and top right adjacent pixels from left to right, the replacement means 2420 may fetch the top right and top right adjacent pixels from right to left.

[000225] Alternatively, the replacement means 2420 may replace a pixel value of the first adjacent pixel P(-1,-1) 2110 with an average value of all adjacent pixels available among the adjacent pixels of top, top right, left and bottom left of the current block 2100, rather than using the adjacent pixel initially found available among the top or left adjacent pixels to replace the first adjacent pixel P(-1,-1) 2110.

[000226] Figure 22 is a diagram for describing a process of replacing an unavailable adjacent pixel, according to another embodiment of the present invention.

[000227] Referring to Figure 22, it is assumed that a first adjacent pixel whose availability is first determined between adjacent pixels is an adjacent pixel P(-1,2nT-1) 2210 located to the lower left of the current block 2200. In other words, In other words, the availability determiner 2410 first determines availability of the first adjacent pixel P(-1, 2nT-1) 2210. If it is determined that the first adjacent pixel P(-1,2nT-1) 2210 is unavailable, the means of replacement 2420 searches for an available adjacent pixel among the adjacent pixels sequentially according to a predetermined order based on the first adjacent pixel P(-1.2nT-1) 2210 and replaces the first adjacent pixel P(-1.2nT-1) 2210 with a second available adjacent pixel that is initially found. For example, the replacement means 2420 searches left and bottom left adjacent pixels of the current block 2200 according to a first search direction from bottom to top based on the first adjacent pixel P(-1.2nT-1) 2210 and if the second available adjacent pixel is not found in the left and bottom left adjacent pixels, searches for the second available adjacent pixel by fetching top and top right adjacent pixels of the current block 2200 according to a second search direction from left to left. right. The replacement means 2420 replaces the first adjacent pixel P(-1.2nT-1) 2210 with the second available adjacent pixel initially found in accordance with such search direction and a search order. For example, if an adjacent pixel P(-1,nT-2) 2220 among the left adjacent pixels is the second available adjacent pixel that is initially found according to the search order, the replacement means 2420 substitutes a value of pixel of the first adjacent pixel P(-1,2nT-1) 2210 by a pixel value of the second adjacent pixel P(-1, nT-2) 2220.

[000228] Similar to the embodiment described above, the replacement means 2420 replaces a third remaining unavailable adjacent pixel excluding the first adjacent pixel P(- 1.2nT-1) 2210 with a previously processed and replaced adjacent pixel or an originally adjacent pixel available based on a predetermined search direction. For example, the replacement means 2420 replaces the first adjacent pixel P(-1,2nT-1) 2210 with the second adjacent pixel P(-1, nT-2) 2220, and then replaces a next unavailable adjacent pixel P( - 1, 2nT-2) with the first adjacent pixel P(-1,2nT-1) 2210 . if the first adjacent pixel P(-1.2nT-1) 2210 is originally available, a process of replacing the first adjacent pixel P(-1.2nT-1) 2210 is skipped, and thereby the replacement means 2420 replaces a pixel value of the adjacent pixel P(-1, 2nT- 2) with the pixel value of the first adjacent pixel P(-1,2nT-1) 2210 .

[000229] Such replacement process is repeated for all third adjacent unavailable pixels. In figure 22, the second adjacent pixel P(-1, nT-2) 2220 and an adjacent pixel p(nT+1, -1) 2230 that are available between the left and top adjacent pixels are not replaced and maintain their values of original pixels. As such, the replacement means 2420 fetches the left and top adjacent pixels of the current block 2200 respectively from top to bottom and left to right based on the first adjacent pixel P(-1.2nT-1) 2210 and replaces the third adjacent pixel with an adjacent pixel immediately below or to the left. In other words, the replacement means 2420 replaces the third unavailable adjacent pixels located to the left and bottom left of the current block 2200, excluding the first adjacent pixel P(-1.2nT-1) 2210 and the originally available adjacent pixel, with the respective immediately below adjacent pixel, and replaces the third unavailable adjacent pixels located at the top and upper right of the current block 2200 with a respective immediately left adjacent pixel. As such, the replacement means 2420 respectively replaces a plurality of adjacent third pixels located to the left of the current block 2200 from the bottom to the top with a respective adjacent pixel below, and respectively replaces a plurality of adjacent third pixels located on the top of the current block 2200 from left to right with a respective left adjacent pixel. As described above, the respective left or bottom adjacent pixel used for replacement may be a pre-replaced or originally available adjacent pixel.

[000230] As described above, a search order or a search direction of the top and left adjacent pixels can be changed. In other words, the replacement means 2420 may first search the top and top right adjacent pixels of the current block 2200 from right to left, and if an adjacent pixel is unavailable, it may then search the left adjacent pixels. bottom and left of the current block 2200 from top to bottom to fetch a second adjacent pixel to replace the first adjacent pixel P(-1,2nT-1) 2210 .

[000231] Figure 23 is a diagram for describing a process of replacing an unavailable adjacent pixel, according to another embodiment of the present invention.

[000232] Referring to Figure 23, it is assumed that a first adjacent pixel whose availability is initially determined between adjacent pixels is an adjacent pixel P(2nT-1,-1) 2310 located uppermost to the right of the current block 2300. In other words, In other words, the availability determiner 2410 first determines availability of the first adjacent pixel P(2nT-1,-1) 2310. If the first adjacent pixel P(2nT-1,-1) 2310 is determined to be unavailable, the means of replacement 2420 searches for an available adjacent pixel by sequentially searching the adjacent pixels according to a predetermined direction based on the first adjacent pixel P(2nT-1,-1) 2310 and replacing the first adjacent pixel P(2nT-1,-1) 2310 by a second available adjacent pixel initially found. For example, the replacement means 2420 searches top and top right adjacent pixels of the current block 2300 according to a first right-to-left search direction based on the first adjacent pixel P(2nT-1,-1) 2310 , and if the second adjacent pixel is unavailable in the upper right and top adjacent pixels, searches for the second available adjacent pixel by searching for lower left and left adjacent pixels of the current block 2300 from the top to the bottom. The replacement means 2420 replaces the first adjacent pixel P(2nT-1,-1) 2310 with the second available adjacent pixel initially found in accordance with such search direction and search order. For example, when an adjacent pixel P(nT+1, -1) 2320 among the upper adjacent pixels is a second available adjacent pixel that is initially found according to a search order, the replacement means 2420 substitutes a pixel value of the first adjacent pixel P(2nT- 1,-1) 2310 with a pixel value of the second adjacent pixel P(nT+1, -1) 2320.

[000233] Furthermore, the replacement means 2420 replaces a third remaining unavailable adjacent pixel excluding the first adjacent pixel P(2nT-1,-1) 2310 with a preprocessed and replaced or originally available adjacent pixel based on a default search direction. For example, the replacement means 2420 replaces the first adjacent pixel P(2nT-1,-1) 2310 with the second adjacent pixel P(nT+1, -1), and then replaces a next unavailable adjacent pixel P(2nT -2, - 1) with the first adjacent pixel P(2nT-1,-1) 2310.

[000234] If the first adjacent pixel P(2nT-1,-1) 2310 is originally available, a process of replacing the first adjacent pixel P(2nT-1,-1) 2310 is skipped, and thereby the replacement means 2420 replaces a pixel value of the adjacent pixel P(2nT-2, -1) with an original pixel value of the first adjacent pixel P(2nT-1,-1) 2310.

[000235] Such replacement process is repeated on all third adjacent unavailable pixels. In figure 23, the second available adjacent pixel P(nT+1,-1) 2320 and one available adjacent pixel P(-1,nT-1) 2320 between the left and top adjacent pixels are not replaced and maintain their values of original pixels. As such, the replacement means 2420 fetches the left and top adjacent pixels of the current block 2300 respectively from right to left and top to bottom based on the first adjacent pixel P(2nT-1,-1) 2310, and sequentially replaces the unavailable third adjacent pixels with a left or top adjacent pixel. In other words, the replacement means 2420 sequentially replaces the unavailable third adjacent pixels located at the top and upper right of the current block 2300 with a respective immediately left adjacent pixel, and the unavailable third adjacent pixels located at the lower left and left of the respective block. current block 2300 by an immediately above respective adjacent pixel, excluding the first adjacent pixel P(2nT-1,-1) 2310 and an originally available adjacent pixel.

[000236] As described above, a search order and a search direction of the top and left adjacent pixels can be changed. In other words, the replacement means 2420 first searches the left and lower left adjacent pixels of the current block 2300 from the bottom to the top, and if an adjacent pixel is unavailable, then searches the upper right and left adjacent pixels. of the current block 2300 from left to right in order to search for a second adjacent pixel to replace the first adjacent pixel P(2nT-1, -1) 2310.

[000237] Meanwhile, if a process of replacing unavailable adjacent pixels between adjacent pixels is completed, a process of filtering adjacent pixels can be carried out. Whether to use a filtered adjacent pixel can be determined based on a current block size. For example, the filtered adjacent pixel can be used only when the current block size is 16x16.

[000238] Figure 25A is a diagram of filtered adjacent pixels 2510 and 2520 of a current block 2500.

[000239] Referring to Figure 25A, the adjacent pixels of the current block 2500. Here, when a current block size 2500 is nTxnT, X can be 2nT and Y can be 2nT.

[000240] When ContextOrg[n] indicates original pixels X+Y on top and left of the current block 2500 having the size of nTxnT, where n is an integer from 0 to X+Y-1, n is 0 in a lowest adjacent pixel between left-adjacent pixels, that is, ContextOrg[0], and n is X+Y-1 in a right-most adjacent pixel between top-adjacent pixels, that is, ContextOrg[X+Y-1].

[000241] Figure 25B is a reference diagram for describing a process of filtering an adjacent pixel of a current block.

[000242] Referring to Figure 25B, when ContextOrg[n] indicates adjacent pixels at the top and left of a current block, where n is an integer from 0 to 4nT-1, adjacent pixels can be filtered through a weighted average value between adjacent pixels. When ContextFiltered1[n] indicates an adjacent pixel filtered at once, adjacent pixels filtered by applying a 3-lead filter to the adjacent pixels ContextOrg[n] can be obtained according to an equation ContextFiltered1[n]=(ContextOrg[n-1 ]+2*ContextOrg[n]+ ContextOrg [n+1])/4. Similarly, a twice-filtered adjacent pixel ContextFiltered2[n] can be generated by recomputing a weighted average value between adjacent pixels filtered once ContextFiltered1[n]. For example, adjacent pixels filtered by applying a 3-lead filter to adjacent pixels filtered ContextFiltered1[n] can be generated according to an equation ContextFiltered2[n]=(ContextFiltered1[n- 1]+2*ContextFiltered1 [n]+ContextFiltered1 [n+1])/4.

[000243] Figure 26 is a flowchart illustrating a video intraprediction method, according to an embodiment of the present invention.

[000244] In operation 2610, the availability determiner 2410 determines availability of a predetermined number of adjacent pixels used for intraprediction of a current block between blocks obtained by dividing a frame that forms a video into a hierarchical structure. As described above, if an adjacent pixel included in an adjacent block of a different slice from a slice including an inter-predicted adjacent block or the current block exists among the predetermined number of adjacent pixels, the availability determinate 2410 determines the pixel corresponding adjacent as an unavailable adjacent pixel.

[000245] In operation 2620, if a first adjacent pixel is unavailable in the predetermined number of adjacent pixels, the replacement means 2420 searches for an available second adjacent pixel by searching the predetermined number of adjacent pixels in a predetermined direction based on the first pixel adjacent. In operation 2630, the replacement means 2420 replaces a pixel value of the first adjacent pixel with a pixel value of the second adjacent pixel. If the first adjacent pixel at a predetermined location is available, the first adjacent pixel is used as a reference pixel for the intraprediction of the current block, and a process of replacing the first adjacent pixel is skipped. As such, when the first adjacent pixel is unavailable and thereby replaced with the second adjacent pixel or is available and thus the replacement process is skipped, a process of replacing an unavailable third adjacent pixel among the adjacent pixels is performed.

[000246] As described above, the replacement means 2420 according to one embodiment determines availability of a first adjacent pixel located in an upper left corner of the current block, if the first adjacent pixel is unavailable, seeks the second available adjacent pixel by fetching top and top right adjacent pixels from left to right based on the first adjacent pixel, and if the second adjacent pixel is unavailable in the top and top right adjacent pixels, fetches the second available adjacent pixel by fetch adjacent pixels from the bottom left and left from the top to the bottom based on the first adjacent pixel. The replacement means 2420 determines an initially available adjacent pixel according to such a search direction and a search order as the second adjacent pixel. Next, the replacement means 2420 replaces the pixel value of the first adjacent pixel with the pixel value of the second adjacent pixel. Furthermore, the replacement means 2420 replaces at least one unavailable third adjacent pixel located to the left and lower left of the current block with an adjacent pixel immediately above, excluding the first adjacent pixel and an originally available adjacent pixel, and replaces at least one third unavailable adjacent pixel located at the top and upper right of the current block by an adjacent pixel immediately to the left. In other words, the replacement means 2420 performs a process of replacing third adjacent pixels not available at other locations by deleting the first adjacent pixel at a predetermined location using an immediately adjacent pixel in a predetermined direction.

[000247] substitution means 2420 according to another embodiment determines availability of a first adjacent pixel located to the lower left of the current block, and if the first adjacent pixel is unavailable, determines an available adjacent pixel initially found as the second adjacent pixel by fetching the left and bottom left adjacent pixels from the bottom to the top based on the first adjacent pixel. If the second adjacent pixel is unavailable in the left and bottom left adjacent pixels, the substitution means 2420 determines an initially found available adjacent pixel as the second adjacent pixel by searching the top right and top right adjacent pixels from the left to on the right. Furthermore, the replacement means 2420 replaces the pixel value of the first adjacent pixel with the pixel value of the second adjacent pixel. Furthermore, the replacement means 2420 sequentially replaces the unavailable third adjacent pixels on the respective lower left and immediately below with the respective immediately below adjacent pixel, and the respective unavailable third adjacent pixels on the top and upper right with the respective immediately left adjacent pixel, excluding the first adjacent pixel and the originally available adjacent pixel. In other words, the replacement means 2420 performs a process of replacing third adjacent pixels not available at other locations with an immediately adjacent pixel in a predetermined direction, deleting the first adjacent pixel at the predetermined location.

[000248] substitution means 2420 according to another embodiment determines availability of a first adjacent pixel located in the upper rightmost part of the current block, and if the first adjacent pixel is unavailable, determines an available adjacent pixel initially found as the second adjacent pixel by fetching top right and top right adjacent pixels from right to left based on the first adjacent pixel. If the second adjacent pixel is unavailable in the top and top right adjacent pixels, the substitution means 2420 determines an available adjacent pixel initially found as the second adjacent pixel by searching left and bottom left adjacent pixels from the top to the bottom. lower part. Next, the substitution means 2420 replaces a pixel value of the first adjacent pixel with a pixel value of the second adjacent pixel. Furthermore, the replacement means 2420 replaces at least one third adjacent unavailable pixel located at the top and upper right of the current block with an adjacent pixel immediately to the right, and replaces at least one third adjacent unavailable pixel located at the left and lower left. of the current block by an adjacent pixel immediately above, excluding the first adjacent pixel and an originally available adjacent pixel. In other words, the replacement means 2420 performs a process of replacing third adjacent pixels not available in other locations by deleting the first adjacent pixel at a predetermined location with an immediately adjacent pixel in a predetermined direction. In operation 2640, the intraprediction execution means 2430 performs intraprediction on the current block using the original adjacent pixels and the substituted adjacent pixels according to availability.

[000249] As described above, the complexity of a process of determining a reference pixel used for intraprediction can be reduced by searching and replacing an available adjacent pixel, based on a predetermined search direction with an unavailable adjacent pixel.

[000250] As programs for carrying out the interprediction method described with reference to Figures 1 to 26 are stored on the computer-readable recording medium, an independent computer system can easily perform operations in accordance with the programs stored on the computer-readable recording medium .

[000251] A computer-readable recording medium storing a program, for example, a disk 26000, in accordance with an embodiment of the present invention will now be described in detail.

[000252] Figure 27A is a diagram of a physical structure of disk 26000 on which a program is stored, in accordance with an embodiment of the present invention. Disc 26000, which is a storage medium, may be a hard drive, a compact disc read-only memory disc (CD-ROM), a Blu-ray disc, or a digital versatile disc (DVD). Disk 26000 includes a plurality of concentric tracks Tr that are individually divided into a specific number of Se sectors in a circumferential direction of disk 26000. In a specific region of disk 26000, a program that performs the interprediction method described above may be assigned and stored.

[000253] An embedded computer system utilizing a storage medium that stores a program for performing the intraprediction method as described above will now be described with reference to Figure 27B.

[000254] Figure 27B is a diagram of a disk drive 26800 for writing and reading a program using disk 26000. A computer system 27000 can store a program that performs an intraprediction method in accordance with an embodiment of the present invention, in the disk 26000 via disk drive 26800. To run the program stored on disk 26000 on computer system 27000, the program can be read from disk 26000 and transmitted to computer system 26700 using disk drive 27000.

[000255] program that performs an intraprediction method according to an embodiment of the present invention can be stored not only on the disk 26000 illustrated in Figure 27A or 27B but also on a memory card, a ROM cassette, or a solid state drive ( SSD).

[000256] A system to which the intraprediction method described above is applied will be described below.

[000257] Figure 28 is a diagram of a general structure of a content delivery system 11000 for providing a content distribution service. A service area of a communication system is divided into cells of predetermined size, and wireless base stations 11700, 11800, 11900 and 12000 are installed in these cells, respectively.

[000258] content delivery system 11000 includes a plurality of independent devices. For example, the plurality of independent devices, such as a computer 12100, a personal digital assistant (PDA) 12200, a video camera 12300, and a cell phone 12500, are connected to the Internet 11100 through an Internet service provider 11200, a communication network 11400, and wireless base stations 11700, 11800, 11900, and 12000.

[000259] However, the content delivery system 11000 is not limited as illustrated in Figure 28, and devices can be selectively connected to it. The plurality of independent devices may be directly connected to the communication network 11400, not through the wireless base stations 11700, 11800, 11900 and 12000.

[000260] Video camera 12300 is an imaging device, e.g., a digital video camera, that is capable of capturing video images. The cellular telephone 12500 may employ at least one communication method between multiple protocols, e.g., Personal Digital Communications (PDC), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (W-CDMA) , Global System for Mobile Communications (GSM), and Personal Handyphone System (PHS).

[000261] The video camera 12300 can be connected to a streaming server 11300 via the wireless base station 11900 and the communication network 11400. The streaming server 11300 allows content received from a user via the video camera 12300 to be streamed through a real-time broadcast. Content received from the video camera 12300 may be encoded using the video camera 12300 or the streaming server 1130. Video data captured by the video camera 12300 may be transmitted to the streaming server 1130 via computer 12100.

[000262] Video data captured by a camera 12600 may also be transmitted to the streaming server 1130 via the computer 12100. The camera 12600 is an imaging device capable of capturing both still images and video images, similar to a digital camera . Video data captured by camera 12600 may be encoded using camera 12600 or computer 12100. Software that performs video encoding and decoding may be stored on a computer-readable recording medium, e.g., a CD-ROM disk, a floppy disk, a hard disk drive, an SSD, or a memory card, which may be accessible by the computer 12100.

[000263] If video data is captured by a camera built into the cell phone 12500, the video data can be received from the cell phone 12500.

[000264] Video data may also be encoded by a large-scale integrated circuit (LSI) system installed in the video camera 12300, cell phone 12500, or camera 12600.

[000265] content delivery system 11000 may encode content data recorded by a user using the video camera 12300, the camera 12600, the cell phone 12500, or other imaging device, e.g., content recorded during a concert, and transmit the encoded content data to the streaming server 11300. The streaming server 11300 may transmit the content data encoded in a type of a streaming content to other clients requesting the content data.

[000266] Clients are devices capable of decoding the encoded content data, e.g., the computer 12100, the PDA 12200, the video camera 12300, or the cell phone 12500. In this way, the content delivery system 11000 allows that clients have received and reproduce the encoded content data. Additionally, the content delivery system 11000 allows clients to receive the encoded content data and decode and reproduce the encoded content data in real time, thereby enabling personal broadcasting.

[000267] The encoding and decoding operations of the plurality of independent devices included in the content delivery system 11000 may be similar to an intraprediction method in accordance with an embodiment of the present invention.

[000268] cellular telephone 12500 included in the content delivery system 11000 according to an embodiment of the present invention will now be described in greater detail with reference to figures 29 and 30.

[000269] Figure 29 illustrates an external structure of the cell phone 12500 to which an intraprediction method is applied, in accordance with an embodiment of the present invention. The cell phone 12500 may be a smart phone, the functions of which are not limited and a large number of the functions of which can be changed or expanded.

[000270] mobile phone 12500 includes an internal antenna 12510 through which a radio frequency (RF) signal can be exchanged with the wireless base station 12000 of Figure 21, and includes a display screen 12520 for displaying images captured by a camera 12530 or images that are received through the antenna 12510 and decoded, for example, a liquid crystal display (LCD) or an organic light emitting diode (OLED) screen. The cellular telephone 12500 includes an operations panel 12540 that includes a control button and a touch panel. If the display screen 12520 is a touch screen, the operation panel 12540 further includes a touch panel of the display screen 12520. The cell phone 12500 includes a speaker 12580 for transmitting voice and sound or other type of unit sound input. The cell phone 12500 further includes the camera 12530, as a charge-coupled device (CCD) camera, for capturing still images and video. The cellular telephone 12500 may further include a storage medium 12570 for storing encoded/decoded data, e.g., still or video images captured by camera 12530, received via e-mail, or obtained in accordance with various modes; and a partition 12560 through which the storage medium 12570 is loaded into the cell phone 12500. The storage medium 12570 may be a flash memory, e.g., a secure digital (SD) card or an electrically erasable programmable read-only memory. (EEPROM) included in a plastic case.

[000271] Figure 30 illustrates an internal structure of the cell phone 12500, according to an embodiment of the present invention. To systemically control portions of the cellular telephone 12500 including the display screen 12520 and the operation panel 12540, a power supply circuit 12700, an operation input controller 12640, an image coding unit 12720, a camera interface 12630 , an LCD controller 12620, an image decoding unit 12690, a multiplexor/demultiplexer 12680, a write/read unit 12670, a modulation/demodulation unit 12660, and a sound processor 12650 are connected to a central controller 12710 through of a 12730 sync bus.

[000272] If a user operates a power button and sets it from a power-off state to a power-on state, the power supply circuit 12700 provides power to all parts of the cell phone 12500 from a battery, thereby mode by setting the cell phone 12500 into an operating mode.

[000273] central controller 12710 includes a central processing unit (CPU), a ROM, and a RAM.

[000274] Although the cell phone 12500 transmits communication data to the outside, a digital signal is generated by the cell phone 12500 under control of the central controller 12710. For example, the sound processor 12650 can generate a digital sound signal, the unit image coding unit 12720 can generate a digital image signal, and text data of a message can be generated through the operation panel 12540 and the operation input controller 12640. When a digital signal is transmitted to the modulation unit/ demodulation 12660 under control of the central controller 12710, the modulation/demodulation unit 12660 modulates a frequency range of the digital signal, and a communication circuit 12610 performs digital-to-analog conversion (DAC) and frequency conversion on the modulated digital sound signal. frequency range. A broadcast signal transmitted from the communication circuit 12610 may be transmitted to a voice communication base station or the wireless base station 12000 via the antenna 12510.

[000275] For example, when the cell phone 12500 is in a conversion mode, a sound signal obtained through the microphone 12550 is transformed into a digital sound signal by the sound processor 12650, under control of the central controller 12710. The signal digital sound can be transformed into a transformation signal through the modulation/demodulation unit 12660 and the communication circuit 12610, and can be transmitted through the antenna 12510.

[000276] When a text message, for example e-mail, is transmitted in a data communication mode, text data of the text message is input through the operation panel 12540 and is transmitted to the central controller 12610 through of the operation input controller 12640. Under control of the central controller 12610, the text data is transformed into a transmission signal through the modulation/demodulation unit 12660 and the communication circuit 12610 and is transmitted to the wireless base station 12000 through antenna 12510.

[000277] To transmit image data in data communication mode, image data captured by camera 12530 is provided to image coding unit 12720 through camera interface 12630. The captured image data can be directly displayed on the screen of display 12520 through the camera interface 12630 and the LCD controller 12620.

[000278] A structure of the image coding unit 12720 may correspond to that of the video coding apparatus 100 described above. The image coding unit 12720 may transform the image data received from the camera 12530 into compressed image data encoded in accordance with a video coding method employed by the video coding apparatus 100 or the image encoder 400 described. above, and then transmit the encoded image data to the multiplexor/demultiplexor 12680. During a recording operation of the camera 12530, a sound signal obtained by the microphone 12550 of the cell phone 12500 can be transformed into digital sound data through the image processor. sound 12650, and digital sound data can be transmitted to the multiplexor/demultiplexor 12680.

[000279] multiplexor/demultiplexor 12680 multiplexes the encoded image data received from the image coding unit 12720 together with the sound data received from the sound processor 12650. A result of multiplexing the data can be transformed into a signal transmission through the modulation/demodulation unit 12660 and the communication circuit 12610, and can then be transmitted through the antenna 12510.

[000280] Although the cell phone 12500 receives communication data from outside, frequency recovery and ADC are performed on a signal received through the antenna 12510 to transform the signal into a digital signal. The 12660 modulation/demodulation unit modulates a frequency range of the digital signal. The frequency range modulated digital signal is transmitted to the video decoding unit 12690, the sound processor 12650, or the LCD controller 12620, according to the type of the digital signal.

[000281] In conversation mode, the cell phone 12500 amplifies a signal received through the antenna 12510, and obtains a digital sound signal by performing frequency conversion and ADC on the amplified signal. A received digital sound signal is transformed into an analog sound signal through the modulation/demodulation unit 12660 and the sound processor 12650, and the analog sound signal is transmitted through the speaker 12580 under control of the central controller 12710 .

[000282] When in data communication mode, data from a video file accessed on an internet website is received, a signal received from the wireless base station 12000 through the antenna 12510 is transmitted as multiplexed data through the wireless base station 12000 modulation/demodulation 12660, and the multiplexed data is transmitted to the multiplexor/demultiplexor 12680.

[000283] To decode the multiplexed data received through the antenna 12510, the multiplexor/demultiplexer 12680 demultiplexes the multiplexed data into a coded video data stream and a coded audio data stream. Through the synchronization bus 12730, the encoded video data stream and the encoded audio data stream are provided to the video decoding unit 12690 and sound processor 12650, respectively.

[000284] A structure of the image decoding unit 12690 may correspond to that of the video decoding apparatus 200 described above. The image decoding unit 12690 may decode the encoded video data to obtain recovered video data and provide the recovered video data to the display screen 12520 through the LCD controller 12620 in accordance with a video decoding method employed by the video decoding apparatus 200 or image decoder 500 described above.

[000285] In this way, the video file data accessed on the internet website can be displayed on the display screen 12520. At the same time, the sound processor 12650 can transform audio data into an analog sound signal and provide the signal analog sound to the speaker 12580. In this way, audio data contained in the video file accessed on the website can also be played back through the speaker 12580.

[000286] cellular telephone 12500 or other type of communication terminal may be a transceiver terminal that includes both a video encoding apparatus and a video decoding apparatus in accordance with an embodiment of the present invention, may be a transceiver terminal including only the video encoding apparatus, or it may be a transceiver terminal including only the video decoding apparatus.

[000287] A communication system in accordance with the present invention is not limited to the communication system described above with reference to figure 28. For example, figure 31 illustrates a digital broadcasting system that employs a communication system, in accordance with a embodiment of the present invention. The digital broadcasting system of Figure 31 can receive a digital broadcast transmitted over a satellite or a terrestrial network using a video encoding apparatus and a video decoding apparatus in accordance with an embodiment of the present invention.

[000288] Specifically, a broadcasting station 12890 transmits a video data stream to a communications satellite or a broadcasting satellite 12900 using radio waves. The broadcasting satellite 12900 transmits a broadcast signal, and the broadcast signal is transmitted to a satellite broadcast receiver through a home antenna 12860. In every home, an encoded video stream can be decoded and played back by a broadcast receiver. TV 12810, a frequency converter 12870 or other device.

[000289] When a video decoding apparatus in accordance with an embodiment of the present invention is implemented in a playback apparatus 12830, the playback apparatus 12830 can analyze and decode a coded video stream recorded on a storage medium 12820, such as a disk or a memory card to recover digital signals. In this way, the recovered video signal can be reproduced, for example, on a 12840 monitor.

[000290] In the frequency signal converter 12870 connected to the antenna 12860 for a terrestrial/satellite broadcast or a cable antenna 12850 for receiving a cable television (TV) broadcast, a video decoding apparatus in accordance with an embodiment of the present invention can be installed. Data transmitted from the 12870 frequency converter can also be played back on a 12880 TV monitor.

[000291] As another example, a video decoding apparatus according to an embodiment of the present invention can be installed in the TV receiver 12810 instead of the frequency signal converter 12870.

[000292] An automobile 12920 that has a suitable antenna 12910 can receive a signal transmitted from the satellite 12900 or the wireless base station 11700 of Figure 21. A decoded video can be played on a display screen of a navigation system. car 12930 installed on car 12920.

[000293] A video signal can be encoded by a video coding apparatus in accordance with an embodiment of the present invention and can then be stored on a storage medium. Specifically, an image signal may be stored on a DVD disc 12960 by a DVD recorder or may be stored on a hard disk by a hard disk recorder 12950. As another example, the video signal may be stored on a card SD 12970. If the hard disk recorder 12950 includes a video decoding apparatus in accordance with an embodiment of the present invention, a video signal recorded on the DVD disc 12960, the SD card 12970, or other storage medium can be played back on the 12880 TV monitor.

[000294] automobile navigation system 12930 may not include the camera 12530, the camera interface 12630, and the image coding unit 12720 of Figure 30. For example, the computer 12100 and the TV receiver 12810 may not be included in camera 12530, camera interface 12630, and an image coding unit 12720 of Figure 30.

[000295] Figure 32 is a diagram illustrating a network structure of a cloud computing system using a video encoding apparatus and a video decoding apparatus, in accordance with an embodiment of the present invention.

[000296] cloud computing system may include a cloud computing server 14000, a user database (DB) 14100, a plurality of computing resources 14200, and a user terminal.

[000297] cloud computing system provides an on-demand outsourcing service of the plurality of computing resources 14200 over a data communication network, e.g., Internet, in response to a request from the user terminal. Under a cloud computing environment, a service provider provides users with desired services by combining computing resources in data centers located in physically different locations using virtualization technology. A service user does not have to install computing resources, for example, an application, storage, operating system (OS), and security, on his own terminal to use them, but can select and use desired services among services on a virtual space generated through virtualization technology, at a desired point in time.

[000298] A user terminal of a specified service user is connected to the cloud computing server 14000 via a data communication network including the Internet and a mobile telecommunications network. User terminals may be provided with cloud computing services, and particularly video playback services, from the cloud computing server 14000. The user terminals may be various types of electronic devices capable of being connected to the Internet, e.g. , a desktop PC 14300, a smart TV 14400, a smart phone 14500, a notebook computer 14600, a portable multimedia player (MPM) 14700, a tablet PC 14800 and the like.

[000299] cloud computing server 14000 can combine the plurality of computing resources 14200 distributed in a cloud network and provide user terminals with a combination result. The plurality of computing resources 14200 may include various data services, and may include data uploaded from user terminals. As described above, the cloud computing server 14000 can provide user terminals with desired services by combining video database distributed in different regions according to virtualization technology.

[000300] User information about users who have subscribed to a cloud computing service is stored in user DB 14100. The user information may include recording information, addresses, names, and personal credit information of users. User information may also include video indexes. Here, the indexes may include a list of videos that have already been played, a list of videos that are currently playing, a pause point for a video that was playing, and the like.

[000301] Information about a video stored in user DB 14100 can be shared between user devices. For example, when a video service is provided to notebook computer 14600 in response to a request from notebook computer 14600, a playback history of the video service is stored in user DB 14100. When a request to play this video service is received from the smart phone 14500, the cloud computing server 14000 fetches and plays that video service, based on the user DB 14100. When the smart phone 14500 receives a stream of video data from the cloud computing server 14000, a process of playing video by decoding the video data stream is similar to an operation of the cell phone 12500 described above with reference to Figure 30.

[000302] cloud computing server 14000 may refer to a playback history of a desired video service stored in user DB 14100. For example, cloud computing server 14000 receives a request to play a video stored in User DB 14100, from a user terminal. If that video was being played, then a method of streaming that video, executed by the cloud computing server 14000, may vary according to the request from the user terminal, that is, according to whether the video will be played, starting from a start of it or a pause point of it. For example, if the user terminal requests to play the video starting from the beginning thereof, the cloud computing server 14000 transmits streaming data of the video starting from a first frame thereof to the user terminal. If the user terminal requests to play the video, starting from the pause point of the video, the cloud computing server 14000 transmits streaming data of the video starting from a frame corresponding to the pause point, to the user terminal. user.

[000303] In this case, the user terminal may include a video decoding apparatus as described above. As another example, the user terminal may include a video encoding apparatus as described above. Alternatively, the user terminal may include both video decoding apparatus and video encoding apparatus as described above.

[000304] Various applications of a video coding method, a video decoding method, a video coding apparatus, and a video decoding apparatus in accordance with embodiments of the present invention described above have been described above with reference to the figures 27A to 32. However, methods of storing the video encoding method and the video decoding method on a storage medium or methods of implementing the video encoding apparatus and the video decoding apparatus on a device, in accordance with With various embodiments of the present invention, the embodiments described above with reference to Figures 27A to 32 are not limited.

[000305] According to one or more embodiments of the present invention, the complexity of a process of determining a reference pixel used for intraprediction can be reduced by searching and replacing an available adjacent pixel, based on a predetermined search direction, with an adjacent pixel is unavailable.

[000306] Although the present invention has been particularly well described and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. present invention as defined by the following claims.

Claims (1)

1. VIDEO INTRAPREDICTION METHOD, the method characterized by comprising: determining (2610) availability of a predetermined number of adjacent pixels used for intraprediction of a current block having a size of nTxnT, where nT is an integer; when the entire predetermined number of adjacent pixels is unavailable, replacing the pixel values of the entire predetermined number of adjacent pixels with a predetermined value based on the bit depth of the pixel; when there are one or more adjacent pixels available among the predetermined number of adjacent pixels and a first adjacent pixel (2210) among the predetermined number of adjacent pixels is not available, wherein the first adjacent pixel (2210) is located at the bottom between the pixels 2nT adjacent pixels including nT adjacent pixels, adjacent to the left side of the current block and nT adjacent pixels located below the nT adjacent pixels, adjacent to the left side of the current block, search (2620) for a second available adjacent pixel closest to the first pixel adjacent by searching the predetermined number of adjacent pixels in a predetermined direction from an adjacent pixel, adjacent to the first adjacent pixel, the predetermined direction indicating a search direction from bottom to top along a left side of the current block and the left to right along a top side of the current block; when a second available adjacent pixel is found, replacing a pixel value of the first adjacent pixel with a pixel value of the second available adjacent pixel (2630); when there is at least one unavailable adjacent pixel located on the left side of the current block other than the first adjacent pixel, replace a pixel value of the at least one unavailable adjacent pixel located on the left side of the current block sequentially from bottom to top along the side left of the current block with a pixel value of a lower adjacent pixel located directly below the at least one unavailable adjacent pixel; when there is an unavailable adjacent pixel located on the top side of the current block, replacing a pixel value of the unavailable adjacent pixel located on the top side of the current block sequentially from left to right along the top side of the current block with a pixel value of one left adjacent pixel located directly on the left side of the unavailable adjacent pixel; and performing intraprediction on the current block using the predetermined number of adjacent pixels comprising the substituted adjacent pixel (2640), wherein determining availability comprises determining adjacent pixels that belong to a slice other than a slice to which the current block belongs or belongs to an adjacent block between predictions, to be unavailable, where the predetermined number of adjacent pixels is (4nT+1).