Patent Publication Number: US-2023164317-A1

Title: Video coding method and apparatus utilizing combination of diverse block partitioning structures

Description:
RELATED APPLICATIONS 
     This application is a continuation application of the International Patent Application Serial No. PCT/KR2016/011332, filed Oct. 11, 2016, which claims priority to the Korean Patent Application Serial No. 10-2016-0130474, filed Oct. 10, 2016. Both of these applications are incorporated by reference herein in their entireties. 
    
    
     TECHNICAL FIELD 
     The present invention relates to an image processing scheme and, more particularly, to a block partitioning structure in video compression schemes, and a method and an apparatus for performing the partitioning on the block partitioning structure. 
     BACKGROUND 
     As the demand for high-resolution, high-definition video increases, the need for high-efficiency video compression technology for next-generation video services has emerged. Based on this need, the standardized MPEG and VCEG jointly established the Joint Collaborative Team on Video Coding (JCT-VC) of the video compression standardization of H.264/AVC, and completed the standardization for HEVC, which is the latest international video compression standard established January 2013. 
     In the video compression technique, a block partitioning structure refers to a unit in which encoding and decoding are performed, and a unit to which main encoding and decoding techniques such as prediction and transform are applied. As the video compression technology develops, the magnitude of blocks for performing encoding and decoding is gradually increasing, and in terms of partitioning type of blocks, more various partitioning forms are supported. In addition, the video compression is performed using units subdivided according to roles of blocks as well as units for performing encoding and decoding. In the HEVC standard, video coding and decoding are performed using unit blocks subdivided according to a block partitioning structure of quad-tree type and roles of prediction and transform. In addition, various forms of block partitioning structures such as a Quad-Tree plus Binary-Tree (QTBT) which is a form of a combination of a quad-tree and a binary-tree, a block partitioning structure of any form, and the like have been proposed for improving video encoding efficiency. 
     SUMMARY 
     It is an object of the present invention to provide a method and apparatus capable of improving encoding efficiency compared to the existing video compression schemes by utilizing a combination of diverse block partitioning structures. 
     It is to be understood, however, that the technical scope of the present invention is not limited to the above-described technical problems, and other technical problems may exist. 
     In order to solve the above problems, a video coding method and apparatus according to an embodiment of the present invention includes a block partitioning information acquisition unit, a block partitioning performance unit, and a block encoding/decoding unit. 
     In order to solve the above problems, a video coding method and apparatus according to an embodiment of the present invention includes a block partitioning information parsing unit, a determination unit relating to whether an additional block partitioning information is required, and an additional block partitioning information acquisition unit. 
     In order to solve the above problems, a video coding method and apparatus according to an embodiment of the present invention includes a color format determination unit of a current picture, a luminance and chrominance component block magnitude comparing unit, an additional block partitioning information acquisition unit, and a block partitioning performance unit. 
     An object of the present invention is to provide a video coding method and apparatus that efficiently performs block partitioning and improves coding efficiency through the block partitioning in a video coding method and apparatus utilizing a combination of diverse block structures. 
     According to an embodiment of the present invention, encoding performance can be improved by utilizing a combination of diverse block partitioning forms. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a block diagram showing a configuration of a video encoding apparatus according to an embodiment of the present invention. 
         FIG.  2    is a block diagram illustrating a configuration of a video decoding apparatus according to an embodiment of the present invention. 
         FIG.  3    is a conceptual diagram illustrating types of various block partitioning and blocks with various block partitioning according to an embodiment of the present invention. 
         FIG.  4    is a table showing a syntax for supporting a block structure with various block partitioning according to an embodiment of the present invention. 
         FIG.  5    shows an example of a color element according to a color format for one block according to an embodiment of the present invention. 
         FIG.  6    shows an example in which a block partitioning structure is used in the same manner for each color element according to an embodiment of the present invention. 
         FIG.  7    shows an example in which a block partitioning structure is used differently for each color element according to an embodiment of the present invention. 
         FIG.  8    is a flowchart illustrating the performing of partitioning and decoding on blocks in a video decoder according to an embodiment of the present invention. 
         FIG.  9    is a flowchart of a block partitioning performance unit according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings attached thereto, so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification. 
     Throughout this specification, when a part is referred to as being ‘connected’ to another part, it includes not only a case where they are directly connected but also a case where the part is electrically connected with another part in between. 
     In addition, when a part is referred to as ‘comprising’ an element throughout the specification, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise. 
     The term ‘a step of doing something’ or ‘a step of something’ used throughout this specification does not mean a step for something. 
     Also, the terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. 
     In addition, the components shown in the embodiments of the present invention are shown independently to represent different characteristic functions, but that does not mean that each component consists of separate hardware or one software constituent unit. That is, each component is described by arranging each component for convenience of explanation, and at least two components of components may be combined to form one component or one component may be partitioned into a plurality of components to perform functions. The integrated embodiments and the separate embodiments of each of these components are also included in the scope of the present invention without departing from the essence of the present invention. 
     In the various embodiments of the present invention described below, the color format refers to types of color components constituting one picture, and the encoding block or encoding unit may be collectively referred to as including a single block or a unit in which encoding and decoding are performed in video coding. The color format is not limited to a YUV format, and may be collectively referred to as including all kinds of a plurality of color formats according to color components for constituting one picture. 
     Hereinafter, a video coding method and apparatus utilizing a combination of diverse block partitioning structures proposed according to an embodiment of the present invention will be described in detail with reference to  FIG.  9   . 
       FIG.  9    is a flowchart of a block partitioning performance unit according to an embodiment of the present invention. 
     The block partitioning information acquiring unit  830  according to one embodiment includes a block partitioning information parsing unit  920 , an additional block partitioning information determination unit  930 , an additional block partitioning information acquisition unit  940 , and a block partitioning information storage unit  950 . 
     The block partitioning information parsing unit  930  performs parsing on block partitioning information from the bitstream to acquire the block partitioning information. 
     The additional block partitioning information determination unit  930  determines whether additional partitioning information is required in partitioning the current block by using a color format of current picture, block depth information, block position information within a picture, block size information, and the like. 
     When the additional block partitioning information determination unit  930  determines that the additional block partitioning information is needed, the additional block partitioning information acquisition unit  940  acquires additional block partitioning information required for determining the block partitioning structure of the current block. The additional block partitioning information required for determining the partitioning structure of the current block may be obtained by parsing from the bitstream or obtained using the color format of current picture, the block depth information, the block position information within the picture, the size information of the block, and the like without parsing from the bitstream. 
     The block partitioning information storage unit  950  stores the block partitioning information acquired by the block partitioning information parsing unit  920  and the additional block partitioning information acquisition unit  940 . 
     Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings attached thereto, so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification. 
     Throughout this specification, when a part is referred to as being ‘connected’ to another part, it includes not only a case where they are directly connected but also a case where the part is electrically connected with another part in between. 
     In addition, when a part is referred to as ‘comprising’ an element throughout the specification, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise. 
     The term ‘a step of doing something’ or ‘a step of something’ used throughout this specification does not mean a step for something. 
     Also, the terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. 
     In addition, the components shown in the embodiments of the present invention are shown independently to represent different characteristic functions, and that does not mean that each component consists of separate hardware or one software constituent unit. That is, each component is described by arranging each component for convenience of explanation, and at least two components of components may be combined to form one component or one component may be partitioned into a plurality of components to perform functions. The integrated embodiments and the separate embodiments of each of these components are also included in the scope of the present invention without departing from the essence of the present invention. 
     In the various embodiments of the present invention described below, the color format refers to types of color components constituting one picture, and the encoding block or encoding unit may be collectively referred to as including a single block or a unit in which encoding and decoding are performed in video coding. The color format is not limited to a YUV format, and may be collectively referred to as including all kinds of a plurality of color formats according to color components for constituting one picture. 
     Hereinafter, a video coding method and apparatus utilizing a combination of diverse block partitioning structures proposed according to an embodiment of the present invention will be described in detail with reference to  FIG.  9   . 
       FIG.  1    is a block diagram illustrating a video encoding method and apparatus according to an embodiment of the present invention. 
     The video encoding method and apparatus according to an embodiment includes an inter prediction unit  120 , an intra prediction unit  125 , a subtraction unit  130 , a transform unit  140 , a quantization unit  150 , an entropy encoding unit  160 , an inverse transform unit  145 , an inverse quantization unit  155 , an adding unit  135 , an in-loop filter unit  180 , and a reconstruction picture buffer  190 . 
     The inter prediction unit  120  performs motion prediction by using the input image  110  and the reconstructed image stored in and the reconstruction picture buffer  190 , thereby generating a prediction signal. 
     The intra prediction unit  125  performs spatial prediction by using pixel values of pre-reconstructed neighboring blocks that are adjacent to the current block to be encoded, thereby generating a prediction signal. 
     The subtraction unit  130  uses the input image and the prediction signal generated through the inter prediction unit  120  or the intra prediction unit  125 , thereby generating a residual signal. 
     The transform unit  140  and the quantization unit  150  perform transform and quantization on the residual signal generated through the subtraction unit  130 , thereby generating a quantized coefficient. 
     The entropy encoding unit  160  performs entropy encoding on the encoding information such as syntax elements and quantized coefficients defined in the video encoder, thereby outputting the bitstream. 
     The inverse transform unit  145  and the inverse quantization unit  155  receive the quantized coefficients and perform inverse quantization and inverse transform in order, thereby generating a reconstructed residual signal. 
     The adding unit  135  generates a reconstructed signal using the prediction signal generated through the inter prediction unit  120  or the intra prediction unit  125  and the reconstructed residual signal. 
     The reconstructed signal is transmitted to the in-loop filter unit  180 . The reconstructed picture to which the filtering is applied is stored in the reconstruction picture buffer  190 , and may be used as a reference picture in the inter prediction unit  120 . 
       FIG.  2    is a block diagram showing the configuration of a video decoding apparatus and method according to an embodiment of the present invention. 
     The video decoding apparatus and method according to one embodiment includes an entropy decoding unit  210 , an inverse quantization unit  220 , an inverse transform unit  230 , an intra prediction unit  240 , an inter prediction unit  250 , adding unit  260 , an in-loop filter unit  270 , and a reconstruction picture buffer  280 . 
     The entropy decoding unit  210  decodes the input bitstream  200  and outputs decoding information such as syntax elements and quantized coefficients. 
     The inverse quantization unit  220  and the inverse transform unit  230  receive a quantizated coefficient and perform inverse quantization and inverse transform in order, thereby outputting a residual signal. 
     The intra prediction unit  240  performs spatial prediction by using pixel values of the pre-reconstructed neighboring blocks adjacent to the current block to be decoded, thereby generating a prediction signal. 
     The inter prediction unit  250  performs motion compensation using a motion vector extracted from the bitstream and a reconstructed picture stored in the reconstruction picture buffer  280 , thereby generating a prediction signal. 
     The prediction signals output from the intra prediction unit  240  and the inter prediction unit  250  are summed with the residual signal through the adding unit  260  and the reconstructed signal generated on a per-block basis includes the reconstructed image. 
     The reconstructed image is transferred to the in-loop filter unit  270 . The reconstructed picture to which the filtering is applied is stored in the reconstruction picture buffer  280  and may be used as a reference picture in the inter prediction unit  250 . 
       FIG.  3    is a conceptual diagram illustrating types of various block partitioning and blocks with various block partitioning according to an embodiment of the present invention. 
     A video coding method and apparatus utilizing diverse block partitioning according to an embodiment includes block partitioning forms including a non-partitioned block  310 , a horizontally partitioned block  320 , a vertically partitioned block  330 , four-partitioned block  340 , and a block structure  350  having diverse block partitioning. 
     According to an embodiment, the non-partitioned block  310  includes a form in which one encoding block is not partitioned, and the horizontally partitioned block  320  according to an embodiment includes a form in which one encoding block is horizontally partitioned. In addition, the vertically partitioned block  330  according to an embodiment includes a form in which one encoding block is vertically partitioned, and the four-partitioned block  340  includes a form in which one encoding block is vertically and horizontally partitioned. The one encoding block includes both a square block and a non-square block. 
     The block structure  350  having diverse block partitioning according to an embodiment includes a block structure of a form in which blocks  310 ,  320 ,  330 , and  340  of diverse block partitioning forms are combined. In the block partitioning structure according to the embodiment, the most upper block  350  may be partitioned into four sub-blocks, i. e., a first sub-block  351 , a second sub-block  352 , a third sub-block  353 , and a fourth sub-block  354 . The first sub-block  351  according to an embodiment is a block represented by the block partitioning form of the block  310  of a non-partitioned form, and the second sub-block  352  is a block represented by block partitioning of the block  340  of a four-partitioned form. The one encoding block may be partitioned into one or more sub-blocks, and the partitioned sub-blocks may be repeatedly partitioned. The second sub-block  352  is partitioned into four sub-sub-blocks, and each sub-sub-block indicates a block represented by block partitioning of the non-partitioned block  310 . The third sub-block  353  is a block represented by the block partitioning of the horizontally partitioned block  320  and the lower end rectangular block  356  of the sub-sub-blocks is a block represented by block partitioning of the vertically partitioned block  330 . The fourth sub-block  354  is a block represented by block partitioning of the four-partitioned block  340 , and the first sub-sub-block and the third sub-sub-block of the fourth sub-block are blocks represented by block partitioning of the vertically partitioned block  330 . Herein, the third sub-sub-block represents an embodiment in which additional vertical partitioning is performed. 
       FIG.  4    is a table showing a syntax for supporting a block structure with various block partitioning according to an embodiment of the present invention. 
     The video coding method and apparatus according to an embodiment of the present invention includes partitioning information  410  regarding whether or not to partition a block into four sub-blocks, partitioning information  420  regarding whether or not to partition a block into two when the block is not partitioned into four sub-blocks, and direction information  430  regarding two-partitioning direction, in order to use a block structure of diverse block partition forms. The partitioning information  420  regarding whether or not to partition a block into two sub-blocks and the direction information  430  regarding two-partitioning direction include information necessary for partitioning one encoding block into two sub-blocks, and may be transmitted in a form of two flags or in a form of information combined into one. 
       FIG.  5    illustrates an example of a color element according to a color format for one block according to an embodiment of the present invention. 
     As an example of color element according to color format according to an embodiment of the present invention, among color formats, this specification shows a YUV  420  format  510  in which a size of a luminance component is different from a size of a chrominance component, and a YUV  444  format  520  in which a size of a luminance component is the same as a size of a chrominance component. In case of the color format in which the luminance component and the chrominance component are different from each other in size, a size of the luminance component block  511  and the chrominance component blocks  512  and  513  is different from each other in constructing one encoding block. In case of the color format in which the luminance component and the chrominance component is the same in the size, the size of the luminance component block  521  and the chrominance component blocks  522  and  523  is the same in constructing one encoding block. However, in the present specification, the color format in which the size of the luminance component and the chrominance component is different from or the same as each other is not limited to the color format constituted with the luminance component and the chrominance component, and includes classification according to component rate of each color element, such as various color formats such as RGB, XYZ, and the like. 
       FIG.  6    shows an example in which a block partitioning structure is used in the same manner for each color element according to an embodiment of the present invention. 
     A video encoding method and apparatus according to an embodiment uses the same block partitioning structure in the luminance component block and the chrominance component block regardless of a color format. The video encoding method and apparatus according to an exemplary embodiment may determine block partitioning structures by using the same block partitioning information in the luminance component block  611  and the chrominance component blocks  612  and  613  of a color format  610  in which the size of the luminance component and the chrominance component is different from each other. The video encoding method and apparatus according to an exemplary embodiment may determine block partitioning structures by using the same block partitioning information in the luminance component block  621  and the chrominance component blocks  622  and  623  of a color format  620  in which the size of the luminance component and the chrominance component is the same. 
       FIG.  7    shows an example in which a block partitioning structure is used differently for each color element according to an embodiment of the present invention. 
     The video coding method and apparatus according to an embodiment selectively uses the same or different block partitioning structure in the luminance component block and the chrominance component block according to the color format. The video encoding method and apparatus according to an embodiment may determine block partitioning structures by using different block partitioning information in the luminance component block  711  and the chrominance component blocks  712  and  713  of a color format  710  in which the size of the luminance component and the chrominance component is different from each other. Herein, the luminance component block  711  and the chrominance component blocks  712  and  713  may be partitioned using different block partitioning structures, based on the block size and the encoding block partitioning depth information. In addition, the video encoding method and apparatus according to an embodiment may determine block partitioning structures by using the same block partitioning information in the luminance component block  721  and the chrominance component blocks  722  and  723  of a color format  720  in which the size of the luminance component and the chrominance component is the same. 
     The video coding method and apparatus according to an embodiment may selectively use the block partitioning structure of the luminance component blocks  711  and  712  and the chrominance component blocks  712 ,  713 ,  722 , and  723 , in accordance with the color format  710  in which the size of the luminance component and the chrominance component is different from each other and the color format  720  in which the size of the luminance component and the chrominance component is the same. 
       FIG.  8    is a flowchart illustrating the performing of partitioning and decoding on blocks in a video decoder according to an embodiment of the present invention. 
     The video coding method and apparatus according to an embodiment may include a block partitioning information acquisition unit  820 , a block partitioning performance unit  830 , and a block decoding unit  840 . 
     The block partitioning information acquisition unit  820  acquires and outputs encoding information on block partitioning from the bitstream. 
     The block partitioning performance unit  830  performs block partitioning using the encoding information on the block partitioning extracted by the block partitioning information acquisition unit  820 . 
     The block decoding unit  840  performs decoding on each decoding unit partitioned through the block partitioning performance. 
     The present invention can be used for manufacturing such as broadcasting equipment manufacturing, terminal manufacturing, and the like, and industries related to source technology.