WO2020143684A1 - 图像预测方法、装置、设备、系统及存储介质 - Google Patents

图像预测方法、装置、设备、系统及存储介质 Download PDF

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Publication number
WO2020143684A1
WO2020143684A1 PCT/CN2020/070976 CN2020070976W WO2020143684A1 WO 2020143684 A1 WO2020143684 A1 WO 2020143684A1 CN 2020070976 W CN2020070976 W CN 2020070976W WO 2020143684 A1 WO2020143684 A1 WO 2020143684A1
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Prior art keywords
current node
prediction
block
division
node
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PCT/CN2020/070976
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English (en)
French (fr)
Inventor
赵寅
杨海涛
陈建乐
张恋
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华为技术有限公司
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Priority claimed from CN201910696741.0A external-priority patent/CN111669583A/zh
Priority to CN202111467815.7A priority Critical patent/CN114157864B/zh
Priority to AU2020205376A priority patent/AU2020205376B2/en
Priority to CN202080001551.3A priority patent/CN112075077B/zh
Priority to CN202111475069.6A priority patent/CN114173114B/zh
Priority to EP20738949.5A priority patent/EP3907988A4/en
Priority to BR112021013444-1A priority patent/BR112021013444A2/pt
Priority to MX2021008340A priority patent/MX2021008340A/es
Priority to CN202111468095.6A priority patent/CN114245113B/zh
Priority to KR1020237043658A priority patent/KR20240005108A/ko
Priority to JP2021539883A priority patent/JP7317973B2/ja
Priority to KR1020217025090A priority patent/KR102616713B1/ko
Priority to CA3125904A priority patent/CA3125904A1/en
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Publication of WO2020143684A1 publication Critical patent/WO2020143684A1/zh
Priority to US17/369,350 priority patent/US11388399B2/en
Priority to US17/843,798 priority patent/US11849109B2/en
Priority to JP2023117695A priority patent/JP7540051B2/ja
Priority to US18/503,304 priority patent/US20240146909A1/en
Priority to AU2024219474A priority patent/AU2024219474A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals

Definitions

  • Embodiments of the present application relate to the technical field of video encoding and decoding, and in particular, to an image prediction method, device, device, system, and storage medium.
  • Digital video capabilities can be incorporated into a variety of devices, including digital TVs, digital live broadcast systems, wireless broadcast systems, personal digital assistants (PDAs), laptop or desktop computers, tablet computers, e-book readers, Digital cameras, digital recording devices, digital media players, video game devices, video game consoles, cellular or satellite radio phones (so-called "smart phones"), video teleconferencing devices, video streaming devices, and the like .
  • Digital video devices implement video compression technology, for example, in the standards defined by MPEG-2, MPEG-4, ITU-T H.263, ITU-T H.264/MPEG-4 Part 10 Advanced Video Coding (AVC), The video compression technology described in the video coding standard H.265/High Efficiency Video Coding (HEVC) standard and extensions to such standards.
  • Video devices can more efficiently transmit, receive, encode, decode, and/or store digital video information by implementing such video compression techniques.
  • Video signals have become the most important way for people to obtain information in their daily lives due to their intuitive and efficient advantages. Due to the large amount of data contained in the video signal, a large amount of transmission bandwidth and storage space are required. In order to effectively transmit and store video signals, it is necessary to compress and encode the video signals. Video compression technology is increasingly becoming an indispensable key technology in the field of video applications.
  • the encoding process mainly includes intra prediction (Intra Prediction), inter prediction (Inter Prediction), transform (Transform), quantization (Quantization), entropy encoding (Entropy encoding), in-loop filtering (in-loop filtering) (mainly De-blocking filtering and other links.
  • intra prediction or inter prediction is performed, and after the residual is obtained, transform and quantization are performed, and finally entropy coding is performed and the code stream is output.
  • the coding block here is an array of pixels of size (M ⁇ N, M may be equal to N or may not be equal to N), and the pixel value of each pixel position is known.
  • Video decoding is equivalent to the reverse process of video encoding.
  • entropy decoding, inverse quantization, and inverse transformation are used to obtain residual information, and whether the current block uses intra prediction or inter prediction is determined according to the decoded code stream. If it is intra-coded, the pixel values of pixels in the reconstructed area around the current image are used to construct a prediction block according to the intra-prediction method used. If it is inter-frame coding, you need to parse out the motion information, and use the parsed motion information to determine the reference block in the reconstructed image, and use the pixel values of the pixels in the reference block as the prediction block (this process is called motion Compensation (motion compensation, MC)), using the prediction block plus residual information to obtain reconstruction information after filtering operation.
  • motion compensation motion compensation
  • a node of 8xM (or Mx8) size is divided into two nodes of 4xM (or Mx4) size using vertical bisection (or horizontal bisection).
  • a 16xM (or Mx16) size node is divided by a vertical three-point (or horizontal three-point)
  • two 4xM (or Mx4) child nodes and an 8xM (or Nx8) child node will be generated.
  • the resolution of the chroma component is 1/2 of the luma component, that is, a 4xM node contains a 4xM luma block and two 2x (M/2) chroma blocks.
  • dividing the current node according to the preset division method may generate 2x2, 2x4, 4x2 and other chroma blocks.
  • the processing complexity of the small chroma block is relatively high, and specifically includes the following three aspects.
  • Intra prediction problem In order to improve the processing speed in hardware design, intra prediction usually processes 16 pixels at a time, while 2x2, 2x4, 4x2 and other chroma blocks contain less than 16 pixels, which reduces the intra prediction Processing performance.
  • Inter-frame prediction of small chroma blocks requires high data bandwidth and also affects the processing speed of decoding.
  • the present application provides an image prediction method, device, equipment, system, and storage medium, which improves the processing performance of image prediction and improves the processing speed of codec.
  • a first aspect of the present application provides an image prediction method.
  • the method includes:
  • the current node division method determine whether dividing the current node based on the division method will result in an image block with a preset size; the image block includes a luma block or a chroma block; When dividing the current node results in an image block having the preset size, use intra prediction for all coding blocks covered by the current node, or use frames for all coding blocks covered by the current node Forecast.
  • the image block of the preset size may be a luminance block with a size smaller than a threshold, and the threshold may be 128, 64, or 32 luma sampling points, or 32, 16, or 8 chroma sampling points.
  • the size of the current node may be greater than or equal to the threshold.
  • the intra prediction can be performed using a normal intra prediction mode (intra mode) for prediction, or an IBC (intra block copy) mode for prediction.
  • intra mode normal intra prediction mode
  • IBC intra block copy
  • all code blocks covered by the current node refer to all code blocks located in the current node area.
  • the coding block may also be a coding unit (coding unit).
  • intra prediction is used for all coding blocks covered by the current node instead of inter prediction.
  • the beneficial effect of the embodiment of the present application is that the present application considers the situation that the image block corresponding to the current node will be divided to obtain a luma block or a chroma block with a preset size.
  • the encoding end or the decoding end uses the current All coding blocks whose nodes are divided or not divided by the root node use intra prediction or inter prediction, which can realize the parallel processing of the luma block or the chroma block of a preset size, and improve the processing performance of image prediction, thereby Improve codec performance.
  • the following two cases belong to the image block with a preset size: a luma block with a first preset size and a chroma block with a second preset size
  • the Using intra prediction for all coding blocks, or using inter prediction for all coding blocks covered by the current node includes: judging whether dividing the current node based on the division mode will result in the first preset size Luma block; when it is determined that dividing the current node based on the dividing method will result in a luma block having the first preset size, intra prediction is used for all coding blocks covered by the current node; In the case where the current node is not divided by the division method and the luminance block with the first preset size is not obtained, intra prediction is used for all coding blocks covered by the current node, or for all coding blocks covered by the current node Inter prediction.
  • intra prediction is used for all coding blocks covered by the current node, or
  • the use of inter prediction for all coding blocks covered by the current node may include: when it is determined that dividing the current node based on the division mode will not result in a luminance block having a first preset size, parsing the current The prediction mode state identifier of the node; when the value of the prediction mode state identifier is the first value, use inter prediction for all coding blocks covered by the current node; or, the value of the prediction mode state identifier is the first In binary value, intra prediction is used for all coding blocks covered by the current node.
  • the image block with a preset size includes a luminance block with a first preset size
  • the judgment is based on the current node Whether the division will result in an image block with a preset size includes: according to the size of the current node and the division mode, determining whether to divide the current node based on the division mode will result in a brightness with a first preset size Piece.
  • the brightness block of the first preset size may be a brightness block with a pixel size of 4 ⁇ 4, or 8 ⁇ 8, or a brightness block with an area of 16 or 32.
  • the brightness block of the first preset size is a pixel size of 4 ⁇ 4 or an area of 16
  • the current Whether the node is divided will result in a brightness block with a first preset size, which may include:
  • the number of sampling points of the current node's luminance block is 64, and the division method is quadtree division; or,
  • the number of sampling points of the brightness block of the current node is 64, and the division method is a tri-tree division; or,
  • the number of sampling points of the luminance block of the current node is 32, and the division method is binary tree division.
  • the intra prediction is used for all coding blocks covered by the current node.
  • the method further includes: Judging whether dividing the current node based on the division mode will result in a chroma block of a second preset size; when determining that dividing the current node based on the division mode will obtain a color having the second preset size
  • intra prediction is used for all coding blocks covered by the current node, or inter prediction is used for all coding blocks covered by the current node.
  • the brightness block with the first preset size may be a 4 ⁇ 4 brightness block or an area 16 brightness block, where the first preset size of the brightness block is a 4 ⁇ 4 brightness block
  • the chroma block of the second preset size may be a chroma block with a pixel size of 2 ⁇ 4, or 4 ⁇ 2, or a chroma block with an area of 8, excluding a pixel size of 2 ⁇ 2 or an area Chroma block of 4.
  • the brightness block with the first preset size may be a 4 ⁇ 4 brightness block or an area 16 brightness block, where the first preset size of the brightness block is a 4 ⁇ 4 brightness block
  • the chroma block of the second preset size may be a brightness block with a pixel size of 4 ⁇ 8 or 8 ⁇ 4, or a brightness block with an area of 32, excluding a pixel size of 4 ⁇ 4 or an area of 16 Brightness block.
  • the chroma block in the second preset size is a chroma block with a pixel size of 2 ⁇ 4, or 4 ⁇ 2, or an area of 8, or a pixel size of 4 ⁇ 8, or 8 ⁇ 4, or
  • determining whether dividing the current node based on the dividing method will result in a chroma block of a second preset size may include:
  • the number of sampling points of the brightness block of the current node is 64, and the division method is binary tree division; or,
  • the number of sampling points of the luminance block of the current node is 128, and the division method is tri-tree division.
  • the image block with a preset size includes a chroma block with a second preset size, and the judgment is based on the current Whether the node is divided will result in an image block with a preset size, including: according to the size and division mode of the current node, determining whether to divide the current node based on the division mode will obtain a chroma with a second preset size Piece.
  • the chroma block of the second preset size may be a chroma block with a pixel size of 2 ⁇ 2, 2 ⁇ 4, or 4 ⁇ 2, or an area of 4 or 8.
  • the determining whether the current node is divided based on the division mode to obtain a chroma block with a second preset size according to the current node size and division mode may include: according to the current node The size and the division mode determine whether dividing the current node based on the division mode will result in a brightness block with a third preset size.
  • the brightness block with the third preset size may be 4 ⁇ 4, 4 ⁇ 8, or 8 ⁇ 4, or a brightness block with an area of 32 or 16.
  • judging whether dividing the current node based on the dividing mode will result in a chroma block of a second preset size may include:
  • the number of sampling points of the current node's luminance block is 64, and the division method is quadtree division; or,
  • the number of sampling points of the brightness block of the current node is 64, and the division method is a tri-tree division; or,
  • the number of sampling points of the luminance block of the current node is 32, and the division method is binary tree division; or,
  • the number of sampling points of the luminance block of the current node is 64, and the division method is binary tree division; or,
  • the number of sampling points of the luminance block of the current node is 128, and the division method is tri-tree division.
  • the chroma block of the second preset size may be a chroma block with a pixel size of 2 ⁇ 4, or 4 ⁇ 2, or an area of 8, excluding a pixel size of 2 ⁇ 2, or an area of 4. Chroma block.
  • the brightness block with the third preset size may be a brightness block with a pixel size of 4 ⁇ 8, or 8 ⁇ 4, or an area of 32, excluding brightness with a pixel size of 4 ⁇ 4 or an area of 16. Piece.
  • judging whether dividing the current node based on the dividing mode will result in a chroma block of the second preset size may include:
  • the number of sampling points of the current node's luminance block is 64, and the division method is binary tree division; or,
  • the number of sampling points of the luminance block of the current node is 128, and the division method is tri-tree division.
  • the covering of the current node Use intra prediction for all coding blocks of, or use inter prediction for all coding blocks covered by the current node, including: parsing the prediction mode status flag of the current node; the value of the prediction mode status flag is first Value, use inter prediction for all coding blocks covered by the current node; or, when the value of the prediction mode state identifier is the second value, use intra prediction for all coding blocks covered by the current node.
  • This implementation is applied to a video decoder, and the prediction mode of all coding blocks obtained by dividing or not dividing the current node as the root node is determined by parsing the prediction mode status flag from the code stream, which only needs to be parsed once compared with the prior art , Improve the processing speed of video decoding.
  • the slice type where the current node is located is not an Intra type.
  • the covering of the current node Use intra prediction for all coding blocks of, or use inter prediction for all coding blocks covered by the current node, including: when the prediction mode of any coding block covered by the current node is inter prediction, Use inter prediction for all coding blocks covered by the current node; or, when the prediction mode of any coding block covered by the current node is intra prediction, use intra prediction for all coding blocks covered by the current node.
  • the any coding block is the first coding block in the decoding order among all coding blocks covered by the current node.
  • This implementation is applied to a video decoder.
  • all codes covered by the current node uses intra prediction, or uses inter prediction on all coding blocks covered by the current node, including: determining whether dividing the current node based on the division method will result in a luminance block of the first preset size; In the case where the current node is divided in the manner of dividing the current node to obtain a luminance block of a first preset size, intra prediction is used for all coding blocks covered by the current node.
  • the intra prediction is used for all coding blocks covered by the current node, or
  • the use of inter prediction for all coding blocks covered by the current node includes: parsing the prediction mode state identifier of the current node; when the value of the prediction mode state identifier is the first value, all the coverage of the current node The coding block uses inter prediction; or, when the value of the prediction mode state identifier is the second value, intra prediction is used for all coding blocks covered by the current node.
  • This implementation is applied to a video decoder, and the prediction mode of all coding blocks obtained by dividing or not dividing the current node as the root node is determined by parsing the prediction mode status flag from the code stream, which only needs to be parsed once compared with the prior art , Improve the processing speed of video decoding.
  • the intra prediction is used for all coding blocks covered by the current node, or
  • the use of inter prediction for all coding blocks covered by the current node includes: when the prediction mode of any coding block covered by the current node is inter prediction, the use of inter prediction for all coding blocks covered by the current node Or, when the prediction mode of any coding block covered by the current node is intra prediction, intra prediction is used for all coding blocks covered by the current node. This implementation is applied to a video decoder.
  • the any coding block is the first coding block in the decoding order among all coding blocks covered by the current node.
  • the intra prediction is used for all coding blocks covered by the current node, or the The use of inter prediction for all coding blocks covered by the current node includes: dividing the luminance blocks included in the current node according to the division manner to obtain divided luminance blocks, and using intra frames for the divided luminance blocks Prediction, using the chroma block included in the current node as a chroma code block, and using intra prediction on the chroma code block; or, dividing the luma block included in the current node according to the division method to obtain Divided luma blocks, using inter prediction on the divided luma blocks, dividing the chroma blocks included in the current node according to the dividing mode, to obtain the divided chroma blocks, and dividing the divided luma blocks Of chroma blocks use inter prediction.
  • the luma block of the current node is always divided, and the chroma block of the current node can be divided in the inter prediction mode.
  • the chroma block of the current node is not divided in intra prediction mode.
  • the intra prediction is used for all coding blocks covered by the current node, or the The use of inter prediction for all coding blocks covered by the current node includes: dividing the luminance blocks included in the current node according to the division manner to obtain divided luminance blocks, and using intra frames for the divided luminance blocks Prediction, using the chroma block included in the current node as a chroma code block, and using intra prediction on the chroma code block; or, dividing the luma block included in the current node according to the division method to obtain For the divided luma block, inter prediction is used for the divided luma block, the chroma block included in the current node is used as a chroma coding block, and inter prediction is used for the chroma coding block.
  • the chroma block of the current node is always not divided, and the luma block is divided according to the luma block division method.
  • This implementation manner does not generate a chroma block of a second preset size that uses intra prediction, thereby solving the problem of intra prediction of a small chroma block, thereby improving the processing speed of video encoding.
  • all The use of inter prediction for all coding blocks covered by the current node includes:
  • the child node may be obtained by dividing the current node once, or may be obtained by dividing N times.
  • N is an integer greater than 1.
  • the division strategy may include no division, one division, or N divisions.
  • N is an integer greater than 1.
  • a second aspect of the present application provides an image prediction device, including:
  • the acquisition module is used to obtain the current node division method
  • the judging module is used for judging whether dividing the current node based on the dividing mode will obtain an image block with a preset size; the image block includes a luma block or a chroma block;
  • the execution module is configured to use intra prediction on all the coding blocks covered by the current node if it is determined that the current node will be divided based on the division mode to obtain an image block having the preset size, or Inter prediction is used for all coding blocks covered by the current node.
  • a third aspect of the present application provides a video encoding device, including a processor and a memory for storing executable instructions of the processor; wherein the processor executes the method as described in the first aspect of the present application.
  • a fourth aspect of the present application provides a video decoding device, including a processor and a memory for storing executable instructions of the processor; wherein the processor executes the method as described in the first aspect of the present application.
  • a fifth aspect of the present application provides an image prediction system, including: a video acquisition device, a video encoding device according to the third aspect of the present application, a video decoding device according to the fourth aspect of the present application, and a display device, the video The encoding device is respectively connected to the video acquisition device and the video decoding device, and the video decoding device is connected to the display device.
  • a sixth aspect of the present application provides a computer-readable storage medium on which a computer program is stored, which is executed by a processor to implement the method according to any one of the first aspect of the present application.
  • a seventh aspect of the present application provides an image prediction method.
  • the method includes:
  • the current node division method where the current node is an image block in a coding tree unit (coding tree unit) in the current image; determine the current node according to the current node division method and the size of the current node Whether the first condition is satisfied; when it is determined that the current node satisfies the first condition, intra prediction is performed on all code blocks belonging to the current node, thereby obtaining predictions of all code blocks belonging to the current node value.
  • the size of the current node is determined according to the size of the coding tree node corresponding to the current node and the division method used to obtain the current node.
  • the type of the slice where the current node is located is B or P. It should be understood that, in the case where the slice type where the current node is located is I, intra prediction should be used by default for all coding blocks covered by the current node.
  • the judging whether the current node meets the first condition according to the division mode of the current node and the size of the current node may occur when the current node is less than or equal to a preset upper limit of size
  • the preset upper limit of the size may be 256, 128 or 64.
  • the first condition may include:
  • the number of sampling points of the current node's luminance block is 64, and the division method is quadtree division; or,
  • the number of sampling points of the brightness block of the current node is 64, and the division method is a tri-tree division; or,
  • the number of sampling points of the luminance block of the current node is 32, and the division method is binary tree division.
  • the method further includes: according to a division manner of the current node And the size of the current node to determine whether the current node satisfies the second condition; when it is determined that the current node satisfies the second condition, use the same prediction method to predict all code blocks belonging to the current node , So as to obtain prediction values of all coded blocks belonging to the current node, and the prediction method is intra prediction or inter prediction.
  • judging whether the current node meets the second condition according to the current node division mode and the current node size may include: according to the current node division mode, the current node size and The current sampling format (Chroma format) determines whether the current node satisfies the second condition.
  • the current sampling format Chroma format
  • the second condition may include:
  • the number of sampling points of the brightness block of the current node is 64, and the division method is binary tree division;
  • the number of sampling points of the brightness block of the current node is 128, and the division method is a tri-tree division;
  • the number of sampling points of the current node's luminance block is 64, and the division method is binary tree division, and the sampling format is 4:2:0;
  • the number of sampling points of the brightness block of the current node is 128, and the division method is a tri-tree division, and the sampling format is 4:2:0; or,
  • the width of the chroma block of the child node of the current node is 2.
  • the prediction using the same prediction method for all coding blocks belonging to the current node includes: parsing the current The prediction mode state identifier of the node; in the case where the value of the prediction mode state identifier is the first value, inter prediction is performed on all coded blocks belonging to the current node; or, the When the value is the second value, intra-prediction is performed on all coded blocks belonging to the current node.
  • the prediction mode status identifier may be a syntax element parsed during the block division process, that is, a syntax element parsed during the coding tree (coding tree).
  • a syntax element parsed during the coding tree coding tree
  • the coding unit prediction mode flag (cu_pred_mode) can no longer be parsed, and its value is a default value corresponding to the value of the prediction mode state identifier.
  • the inter prediction of all coded blocks belonging to the current node includes: Divide the current node according to the current node division method to obtain the child nodes of the current node; determine the unallowed division of the child nodes of the current node according to the size of the child nodes of the current node Way; determine the fast division strategy of the child nodes of the current node according to the disallowed division method of the child nodes of the current node; according to the block division strategy of the child nodes of the current node, obtain the current node’s The coding block corresponding to the child node, and using inter prediction on the corresponding coding block.
  • the child node is restricted to only use inter prediction and the number of brightness sampling points of the child node is 32 (or the product of the node's width and height is 32), the child node is not allowed to use binary tree division (including horizontal binary tree or vertical Binary tree division). If the child node is restricted to only use inter prediction, and the number of brightness sampling points of the child node is 64 (or the product of the node's width and height is 64), then the child node is not allowed to use the tri-tree division (including horizontal tri-tree and vertical Tri-tree division). This judgment method is applicable to the video data formats of YUV4:2:0 and YUV4:2:2.
  • the 8x4 (or 4x8) node division will continue to produce 4x4 blocks, therefore, 8x4 (or 4x8) nodes cannot use vertical binary tree division (or horizontal binary tree division), or cannot continue division.
  • the number of sampling points of the luminance block of the current node is 128, and the division method is horizontal tri-tree division or vertical tri-tree division, the number of sampling points of the luminance block may be 64, and the number of sampling points If the brightness node is 64, if a child node is used to divide the horizontal tri-tree or vertical tri-tree, you will get a 4x4 brightness block. Therefore, when it has been restricted to only use inter prediction, the node with 64 sampling points cannot Use the horizontal trigeminal tree or vertical trigeminal tree to divide, or can't continue to be divided.
  • the intra prediction is performed on all coded blocks belonging to the current node.
  • the method includes: dividing the luminance block included in the current node according to the division manner to obtain a divided luminance block, using intra prediction on the divided luminance block, and using the chroma block included in the current node as Chroma-coded block, intra prediction is used for the chroma-coded block.
  • An eighth aspect of the present application provides an image prediction method.
  • the method includes: obtaining a division mode of a current node, the current node being an image block in a coding tree unit (coding tree unit) in a current image; according to the current The division of nodes and the size of the current node determine whether the current node satisfies the preset condition; when it is determined that the current node satisfies the preset condition, use the same for all coding blocks belonging to the current node
  • the prediction method performs prediction to obtain prediction values of all coded blocks belonging to the current node.
  • the prediction method is intra prediction or inter prediction.
  • the size of the current node may be determined according to the size of the coding tree node corresponding to the current node and the division method used to obtain the current node.
  • judging whether the current node meets the preset condition according to the division mode of the current node and the size of the current node may include: according to the division mode of the current node, the size of the current node and the current A sampling format (Chroma format) to determine whether the current node meets a preset condition.
  • the preset conditions may include:
  • the number of sampling points of the brightness block of the current node is 64, and the division method is binary tree division; or,
  • the number of sampling points of the luminance block of the current node is 128, and the division method is tri-tree division.
  • the prediction by using the same prediction method for all coding blocks belonging to the current node includes: parsing the prediction mode state identifier of the current node; When the value of the prediction mode state identifier is the first value, perform inter prediction on all coded blocks belonging to the current node; or, when the value of the prediction mode state identifier is the second value, Perform intra prediction on all coded blocks belonging to the current node.
  • the inter prediction of all coded blocks belonging to the current node includes: Dividing the current node into the current node to obtain a child node of the current node; according to the size of the child node of the current node, determining the unallowed division mode of the child node of the current node ; Determine the fast division strategy of the child nodes of the current node according to the disallowed division method of the child nodes of the current node; obtain the child of the current node according to the block division strategy of the child nodes of the current node A coding block corresponding to the node, and using inter prediction for the corresponding coding block.
  • the child node is restricted to only use inter prediction and the number of brightness sampling points of the child node is 32 (or the product of the node's width and height is 32), the child node is not allowed to use binary tree division (including horizontal binary tree or vertical Binary tree division). If the child node is restricted to only use inter prediction, and the number of brightness sampling points of the child node is 64 (or the product of the node's width and height is 64), then the child node is not allowed to use the tri-tree division (including horizontal tri-tree and vertical Tri-tree division). This judgment method is applicable to the video data formats of YUV4:2:0 and YUV4:2:2.
  • the 8x4 (or 4x8) node division will continue to produce 4x4 blocks, therefore, 8x4 (or 4x8) nodes cannot use vertical binary tree division (or horizontal binary tree division), or cannot continue division.
  • the number of sampling points of the luminance block of the current node is 128, and the division method is horizontal tri-tree division or vertical tri-tree division, the number of sampling points of the luminance block may be 64, and the number of sampling points If the brightness node is 64, if a child node is used to divide the horizontal tri-tree or vertical tri-tree, you will get a 4x4 brightness block. Therefore, when it has been restricted to only use inter prediction, the node with 64 sampling points cannot Use the horizontal trigeminal tree or vertical trigeminal tree to divide, or can't continue to be divided.
  • a ninth aspect of the present application provides an image prediction method.
  • the method includes: determining a division mode in which the current node is not allowed according to the size of the current node and the prediction mode of the current node, and the current node is the current image
  • the image block in the coding tree unit in coding the fast division strategy of the current node is determined according to the disallowed division method of the current node; the block division strategy of the current node is used to obtain Said coding block corresponding to the current node, and using inter prediction for the corresponding coding block.
  • the size of the current node may be determined according to the size of the coding tree node corresponding to the current node and the division method used to obtain the current node.
  • the determining, according to the size of the current node and the prediction mode of the current node, that the current node is not allowed to be divided includes: determining whether All coding blocks belonging to the current node are only predicted using the inter mode, and it is determined whether the number of sampling points of the luminance block of the current node is 32; when it is determined that all coding blocks belonging to the current node are only predicted using the inter mode, and When it is determined that the number of sampling points of the luminance block of the current node is 32, it is determined that the binary tree is divided into division modes that are not allowed by the current node.
  • the current node is determined according to the size of the current node and the prediction mode of the current node
  • the division methods that are not allowed include: determining whether all coding blocks belonging to the current node use only inter mode for prediction, and determining whether the number of sampling points of the current node's luminance block is 64; When the coding block uses only the inter mode for prediction, and when it is determined that the number of sampling points of the current node's luminance block is 64, it is determined that the tri-tree is divided into division modes that are not allowed by the current node.
  • a tenth aspect of the present application provides an image prediction device.
  • the device includes:
  • An obtaining module used to obtain the division mode of the current node, which is an image block in a coding tree unit (coding tree unit) in the current image;
  • the judging module is used to judge whether the current node satisfies the first condition according to the current node division method and the size of the current node;
  • the execution module is configured to perform intra prediction on all code blocks belonging to the current node under the condition that the current node meets the first condition, so as to obtain prediction values of all code blocks belonging to the current node .
  • the judgment module is further configured to: when it is determined that the current node does not satisfy the first condition, the division of the current node Manner and the size of the current node to determine whether the current node meets the second condition;
  • the execution module is further configured to: when it is determined that the current node meets the second condition, use the same prediction method to predict all coding blocks belonging to the current node, so as to obtain all The prediction value of the coding block.
  • the prediction method is intra prediction or inter prediction.
  • the judging module may be used to judge whether the current node meets the second condition according to the division mode of the current node, the size of the current node and the current sampling format (Chroma format).
  • the execution module is used to:
  • inter prediction is performed on all coded blocks belonging to the current node; or, in the case where the value of the prediction mode state identifier is the second value Next, perform intra prediction on all coded blocks belonging to the current node.
  • the execution module is used to:
  • the execution module is configured to:
  • the coding block uses intra prediction for the chroma coding block.
  • An eleventh aspect of the present application provides an image prediction apparatus.
  • the apparatus includes: an acquisition module for acquiring a division mode of a current node, the current node being an image in a coding tree unit (coding tree unit) in the current image Block; a judgment module, used to judge whether the current node meets a preset condition according to the current node division method and the size of the current node; an execution module, used to determine that the current node satisfies the preset Under the condition, all the coding blocks belonging to the current node are predicted using the same prediction method, so as to obtain the prediction values of all the coding blocks belonging to the current node.
  • the prediction method is intra prediction or inter prediction.
  • the judging module may be used to judge whether the current node meets the preset condition according to the division mode of the current node, the size of the current node and the current sampling format (Chroma format).
  • the execution module is used to:
  • inter prediction is performed on all coded blocks belonging to the current node; or, in the case where the value of the prediction mode state identifier is the second value Next, perform intra prediction on all coded blocks belonging to the current node.
  • the execution module is used to: Divide the current node to obtain the child nodes of the current node; determine the unallowed division method of the child nodes of the current node according to the size of the child nodes of the current node; according to the child nodes of the current node Is not allowed to divide, determine the fast division strategy of the child nodes of the current node; according to the block division strategy of the child nodes of the current node, obtain the coding block corresponding to the child nodes of the current node, and The corresponding coding block uses inter prediction.
  • a twelfth aspect of the present application provides an image prediction apparatus.
  • the apparatus includes: a determining unit configured to determine, based on a size of a current node and a prediction mode of the current node, a division manner in which the current node is not allowed, so The current node is an image block in a coding tree unit (coding tree unit) in the current image; the determining unit is also used to determine the fast division of the current node according to an unallowed division method of the current node Strategy; prediction unit, for obtaining the coding block corresponding to the current node according to the block division strategy of the current node, and using inter prediction for the corresponding coding block.
  • a determining unit configured to determine, based on a size of a current node and a prediction mode of the current node, a division manner in which the current node is not allowed, so The current node is an image block in a coding tree unit (coding tree unit) in the current image; the determining unit is also used to determine the fast division
  • the determination unit is configured to:
  • the determination unit is configured to:
  • the method of the seventh aspect of the present application may be performed by the apparatus of the tenth aspect of the present application.
  • the apparatus of the tenth aspect of the present application For the functionality of the apparatus of the tenth aspect of the present application and its different implementations, reference may be made to the features and implementation of the method of the seventh aspect of the present application.
  • the method of the eighth aspect of the present application can be performed by the apparatus of the eleventh aspect of the present application.
  • the functionality of the apparatus of the eleventh aspect of the present application and its different implementations reference may be made to the features and implementation of the method of the eighth aspect of the present application.
  • the method of the ninth aspect of the present application can be performed by the apparatus of the twelfth aspect of the present application.
  • the apparatus of the twelfth aspect of the present application For the functionality and different implementations of the device of the twelfth aspect of the present application, reference may be made to the features and implementation of the method of the ninth aspect of the present application
  • a thirteenth aspect of the present application provides an apparatus for decoding a video stream, including a processor and a memory.
  • the memory stores instructions that cause the processor to perform the method according to the seventh aspect or the eighth aspect or the ninth aspect.
  • a fourteenth aspect of the present application provides an apparatus for encoding a video stream, which includes a processor and a memory.
  • the memory stores instructions that cause the processor to perform the method according to the seventh aspect or the eighth aspect or the ninth aspect.
  • a fifteenth aspect of the present application provides a computer-readable storage medium on which instructions are stored, which, when executed, cause one or more processors to encode video data.
  • the instructions cause the one or more processors to perform any possible implementation according to the seventh aspect or the eighth aspect or the ninth aspect, or the seventh aspect or the eighth aspect or the ninth aspect.
  • a sixteenth aspect of the present application provides a computer program including a program code that when executed on a computer performs according to the seventh aspect or the eighth aspect or the ninth aspect, or the seventh aspect or the eighth aspect or the ninth aspect Any possible implementation.
  • a seventeenth aspect of the present application provides a computer-readable storage medium on which a code stream is stored, the code stream carrying a prediction mode state identifier of a current node of a current coding tree; the value of the prediction mode state identifier is first The value is used to indicate that the prediction mode of all coded blocks belonging to the current node is inter prediction; or, the value of the prediction mode state identifier is a second value used to indicate all coded blocks belonging to the current node The prediction mode is intra prediction.
  • This application provides an image prediction method, device, equipment, system, and storage medium.
  • the method includes: obtaining a division mode of the current node, and judging whether dividing the current node based on the division mode of the current node will obtain an image block having a preset size, where the image block includes a luma block or a chroma block.
  • intra prediction is used for all coding blocks covered by the current node
  • inter coding is used for all coding blocks covered by the current node prediction.
  • the above method uses intra-frame or inter-frame prediction for all coding blocks of the current node, which can realize parallel processing of all coding blocks of the current node, improve the processing performance of image prediction, and thus increase the processing speed of coding and decoding.
  • FIG. 1A is a block diagram of an example of a video encoding and decoding system 10 for implementing embodiments of the present application;
  • FIG. 1B is a block diagram of an example of a video decoding system 40 for implementing an embodiment of the present application
  • FIG. 2 is a block diagram of an example structure of an encoder 20 for implementing an embodiment of the present application
  • FIG. 3 is a block diagram of an example structure of a decoder 30 for implementing an embodiment of the present application
  • FIG. 4 is a block diagram of an example of a video decoding device 400 for implementing an embodiment of the present application
  • FIG. 5 is a block diagram of another example of an encoding device or a decoding device used to implement an embodiment of the present application
  • FIG. 6 is a schematic block diagram of a block division method for implementing embodiments of the present application.
  • FIG. 7 is a schematic block diagram of an intra prediction used to implement an embodiment of the present application.
  • FIG. 8 is a schematic block diagram of a video communication system for implementing embodiments of the present application.
  • FIG. 9 is a schematic flowchart of a first image prediction method provided by an embodiment of the present application.
  • FIG. 10 is a schematic flowchart of a second image prediction method provided by an embodiment of the present application.
  • FIG. 11 is a schematic flowchart of a third image prediction method provided by an embodiment of the present application.
  • FIG. 12 is a schematic flowchart of a fourth image prediction method provided by an embodiment of the present application.
  • FIG. 13 is a schematic flowchart of a fifth image prediction method provided by an embodiment of the present application.
  • FIG. 14 is a schematic flowchart of a sixth image prediction method provided by an embodiment of the present application.
  • 15 is a schematic diagram of a functional structure of an image prediction device provided by an embodiment of the present application.
  • 16 is a schematic diagram of a hardware structure of a video encoding device provided by an embodiment of the present application.
  • FIG. 17 is a schematic diagram of a hardware structure of a video decoding device provided by an embodiment of the present application.
  • FIG. 18 is a schematic structural diagram of an image prediction system provided by an embodiment of the present application.
  • the corresponding device may include one or more units such as functional units to perform the one or more method steps described (eg, one unit performs one or more steps , Or multiple units, each of which performs one or more of multiple steps), even if such one or more units are not explicitly described or illustrated in the drawings.
  • the corresponding method may include a step to perform the functionality of one or more units (eg, one step executes one or more units Functionality, or multiple steps, each of which performs the functionality of one or more of the multiple units), even if such one or more steps are not explicitly described or illustrated in the drawings.
  • the features of the exemplary embodiments and/or aspects described herein may be combined with each other.
  • Video coding generally refers to processing a sequence of pictures that form a video or video sequence.
  • picture In the field of video coding, the terms “picture”, “frame” or “image” may be used as synonyms.
  • Video coding as used herein means video coding or video decoding.
  • Video encoding is performed on the source side and usually includes processing (eg, by compressing) the original video picture to reduce the amount of data required to represent the video picture, thereby storing and/or transmitting more efficiently.
  • Video decoding is performed on the destination side and usually involves inverse processing relative to the encoder to reconstruct the video picture.
  • the “encoding” of video pictures involved in the embodiments should be understood as referring to the “encoding” or “decoding” of video sequences.
  • the combination of the encoding part and the decoding part is also called codec (encoding and decoding).
  • the video sequence includes a series of pictures, the picture is further divided into slices, and the slices are further divided into blocks.
  • Video coding is performed in units of blocks.
  • a macroblock can be further divided into multiple prediction blocks that can be used for predictive coding.
  • basic concepts such as coding unit (CU), prediction unit (PU), and transform unit (TU) are used to divide a variety of block units functionally and adopt a new tree-based structure Describe it.
  • the CU can be divided into smaller CUs according to the quadtree, and the smaller CUs can be further divided to form a quadtree structure.
  • the CU is the basic unit for dividing and coding the encoded image.
  • PU can correspond to the prediction block and is the basic unit of predictive coding.
  • the CU is further divided into multiple PUs according to the division mode.
  • the TU can correspond to the transform block and is the basic unit for transforming the prediction residual.
  • CU regardless of CU, PU or TU, they all belong to the concept of block (or image block) in essence.
  • the CTU is split into multiple CUs by using a quadtree structure represented as a coding tree.
  • a decision is made at the CU level whether to use inter-picture (temporal) or intra-picture (spatial) prediction to encode picture regions.
  • Each CU can be further split into one, two, or four PUs according to the PU split type.
  • the same prediction process is applied within a PU, and related information is transmitted to the decoder on the basis of the PU.
  • the CU may be divided into transform units (TU) according to other quadtree structures similar to the coding tree used for the CU.
  • quad-tree and binary-tree Quad-tree and binary-tree (Quad-tree and binary tree, QTBT) split frames are used to split code blocks.
  • the CU may have a square or rectangular shape.
  • the image block to be encoded in the current encoded image may be referred to as the current block.
  • the reference block is a block that provides a reference signal for the current block, where the reference signal represents a pixel value within the image block.
  • the block in the reference image that provides the prediction signal for the current block may be a prediction block, where the prediction signal represents a pixel value or a sample value or a sample signal within the prediction block. For example, after traversing multiple reference blocks, the best reference block is found. This best reference block will provide a prediction for the current block. This block is called a prediction block.
  • the original video picture can be reconstructed, that is, the reconstructed video picture has the same quality as the original video picture (assuming no transmission loss or other data loss during storage or transmission).
  • further compression is performed by, for example, quantization to reduce the amount of data required to represent the video picture, but the decoder side cannot fully reconstruct the video picture, that is, the quality of the reconstructed video picture is better than the original video picture. The quality is lower or worse.
  • Several video coding standards of H.261 belong to "lossy hybrid video codec” (ie, combining spatial and temporal prediction in the sample domain with 2D transform coding for applying quantization in the transform domain).
  • Each picture of a video sequence is usually divided into non-overlapping block sets, which are usually encoded at the block level.
  • the encoder side usually processes the encoded video at the block (video block) level.
  • the prediction block is generated by spatial (intra-picture) prediction and temporal (inter-picture) prediction.
  • the encoder duplicates the decoder processing loop so that the encoder and decoder generate the same prediction (eg, intra-frame prediction and inter-frame prediction) and/or reconstruction for processing, ie encoding subsequent blocks.
  • FIG. 1A exemplarily shows a schematic block diagram of a video encoding and decoding system 10 applied in an embodiment of the present application.
  • the video encoding and decoding system 10 may include a source device 12 and a destination device 14, the source device 12 generates encoded video data, and therefore, the source device 12 may be referred to as a video encoding device.
  • the destination device 14 may decode the encoded video data generated by the source device 12, and therefore, the destination device 14 may be referred to as a video decoding device.
  • Various implementations of source device 12, destination device 14, or both may include one or more processors and a memory coupled to the one or more processors.
  • Source device 12 and destination device 14 may include various devices, including desktop computers, mobile computing devices, notebook (eg, laptop) computers, tablet computers, set-top boxes, telephone handsets such as so-called "smart" phones, etc. Devices, televisions, cameras, display devices, digital media players, video game consoles, in-vehicle computers, wireless communication devices, or the like.
  • FIG. 1A depicts the source device 12 and the destination device 14 as separate devices
  • device embodiments may also include both the source device 12 and the destination device 14 or the functionality of both, ie the source device 12 or the corresponding And the destination device 14 or the corresponding functionality.
  • the same hardware and/or software may be used, or separate hardware and/or software, or any combination thereof may be used to implement the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality .
  • a communication connection can be made between the source device 12 and the destination device 14 via the link 13, and the destination device 14 can receive the encoded video data from the source device 12 via the link 13.
  • Link 13 may include one or more media or devices capable of moving the encoded video data from source device 12 to destination device 14.
  • link 13 may include one or more communication media that enable source device 12 to transmit encoded video data directly to destination device 14 in real time.
  • the source device 12 may modulate the encoded video data according to a communication standard (eg, a wireless communication protocol), and may transmit the modulated video data to the destination device 14.
  • the one or more communication media may include wireless and/or wired communication media, such as a radio frequency (RF) spectrum or one or more physical transmission lines.
  • RF radio frequency
  • the one or more communication media may form part of a packet-based network, such as a local area network, a wide area network, or a global network (eg, the Internet).
  • the one or more communication media may include routers, switches, base stations, or other devices that facilitate communication from source device 12 to destination device 14.
  • the source device 12 includes an encoder 20.
  • the source device 12 may further include a picture source 16, a picture pre-processor 18, and a communication interface 22.
  • the encoder 20, the picture source 16, the picture pre-processor 18, and the communication interface 22 may be hardware components in the source device 12, or may be software programs in the source device 12. They are described as follows:
  • Picture source 16 which can include or can be any kind of picture capture device, for example to capture real-world pictures, and/or any kind of pictures or comments (for screen content encoding, some text on the screen is also considered to be encoded Part of the picture or image) generation device, for example, a computer graphics processor for generating computer animation pictures, or for acquiring and/or providing real-world pictures, computer animation pictures (for example, screen content, virtual reality, VR) pictures) in any category of equipment, and/or any combination thereof (eg, augmented reality (AR) pictures).
  • the picture source 16 may be a camera for capturing pictures or a memory for storing pictures.
  • the picture source 16 may also include any type of (internal or external) interface that stores previously captured or generated pictures and/or acquires or receives pictures.
  • the picture source 16 When the picture source 16 is a camera, the picture source 16 may be, for example, a local or integrated camera integrated in the source device; when the picture source 16 is a memory, the picture source 16 may be a local or integrated, for example, integrated in the source device Memory.
  • the interface When the picture source 16 includes an interface, the interface may be, for example, an external interface that receives pictures from an external video source.
  • the external video source is, for example, an external picture capture device, such as a camera, an external memory, or an external picture generation device.
  • the external picture generation device for example It is an external computer graphics processor, computer or server.
  • the interface may be any type of interface according to any proprietary or standardized interface protocol, such as a wired or wireless interface, an optical interface.
  • the picture can be regarded as a two-dimensional array or matrix of pixels.
  • the pixels in the array can also be called sampling points.
  • the number of sampling points in the horizontal and vertical directions (or axes) of the array or picture defines the size and/or resolution of the picture.
  • three color components are usually used, that is, a picture can be represented or contain three sampling arrays.
  • the picture includes corresponding red, green, and blue sampling arrays.
  • each pixel is usually expressed in a luminance/chrominance format or color space.
  • YUV format picture it includes the luminance component indicated by Y (sometimes also indicated by L) and the two indicated by U and V.
  • the luma component Y represents luminance or gray-scale horizontal intensity (for example, both are the same in gray-scale pictures), and the two chroma components U and V represent chroma or color information components.
  • the picture in the YUV format includes a luminance sampling array of luminance sampling values (Y), and two chrominance sampling arrays of chrominance values (U and V). RGB format pictures can be converted or transformed into YUV format and vice versa, this process is also called color transformation or conversion. If the picture is black and white, the picture may include only the brightness sampling array.
  • the picture transmitted from the picture source 16 to the picture processor may also be referred to as original picture data 17.
  • the picture pre-processor 18 is configured to receive the original picture data 17 and perform pre-processing on the original picture data 17 to obtain the pre-processed picture 19 or the pre-processed picture data 19.
  • the pre-processing performed by the picture pre-processor 18 may include trimming, color format conversion (eg, conversion from RGB format to YUV format), color toning, or denoising.
  • the encoder 20 (or video encoder 20) is used to receive the pre-processed picture data 19, and process the pre-processed picture data 19 using a related prediction mode (such as the prediction mode in various embodiments herein), thereby
  • the encoded picture data 21 is provided (the structural details of the encoder 20 will be further described below based on FIG. 2 or FIG. 4 or FIG. 5).
  • the encoder 20 may be used to execute various embodiments described below to implement the application of the chroma block prediction method described in the present application on the encoding side.
  • the communication interface 22 can be used to receive the encoded picture data 21, and can transmit the encoded picture data 21 to the destination device 14 or any other device (such as a memory) through the link 13 for storage or direct reconstruction.
  • the other device may be any device used for decoding or storage.
  • the communication interface 22 may be used, for example, to encapsulate the encoded picture data 21 into a suitable format, such as a data packet, for transmission on the link 13.
  • the destination device 14 includes a decoder 30, and optionally, the destination device 14 may further include a communication interface 28, a picture post-processor 32, and a display device 34. They are described as follows:
  • the communication interface 28 may be used to receive the encoded picture data 21 from the source device 12 or any other source, such as a storage device, such as an encoded picture data storage device.
  • the communication interface 28 can be used to transmit or receive the encoded picture data 21 via the link 13 between the source device 12 and the destination device 14 or through any type of network.
  • the link 13 is, for example, a direct wired or wireless connection.
  • the category of network is, for example, a wired or wireless network or any combination thereof, or any category of private network and public network, or any combination thereof.
  • the communication interface 28 may be used, for example, to decapsulate the data packet transmitted by the communication interface 22 to obtain the encoded picture data 21.
  • Both the communication interface 28 and the communication interface 22 can be configured as a one-way communication interface or a two-way communication interface, and can be used, for example, to send and receive messages to establish a connection, confirm and exchange any other communication link and/or for example encoded picture data Information about data transmission.
  • the decoder 30 (or referred to as the decoder 30) is used to receive the encoded picture data 21 and provide the decoded picture data 31 or the decoded picture 31 (hereinafter, the decoder 30 will be further described based on FIG. 3 or FIG. 4 or FIG. 5 Structural details).
  • the decoder 30 may be used to implement various embodiments described below to implement the application of the chroma block prediction method described in the present application on the decoding side.
  • the post-picture processor 32 is configured to perform post-processing on the decoded picture data 31 (also referred to as reconstructed picture data) to obtain post-processed picture data 33.
  • the post-processing performed by the image post-processor 32 may include: color format conversion (for example, conversion from YUV format to RGB format), color adjustment, retouching or resampling, or any other processing, and may also be used to convert the post-processed image data 33transmitted to the display device 34.
  • the display device 34 is used to receive post-processed picture data 33 to display pictures to a user or viewer, for example.
  • the display device 34 may be or may include any type of display for presenting reconstructed pictures, for example, an integrated or external display or monitor.
  • the display may include a liquid crystal display (liquid crystal display (LCD), organic light emitting diode (OLED) display, plasma display, projector, micro LED display, liquid crystal on silicon (LCoS), Digital light processor (digital light processor, DLP) or any other type of display.
  • FIG. 1A illustrates the source device 12 and the destination device 14 as separate devices
  • device embodiments may also include the functionality of the source device 12 and the destination device 14 or both, ie, the source device 12 or The corresponding functionality and the destination device 14 or corresponding functionality.
  • the same hardware and/or software may be used, or separate hardware and/or software, or any combination thereof may be used to implement the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality .
  • Source device 12 and destination device 14 may include any of a variety of devices, including any type of handheld or stationary devices, such as notebook or laptop computers, mobile phones, smartphones, tablets or tablet computers, cameras, desktops Computers, set-top boxes, televisions, cameras, in-vehicle devices, display devices, digital media players, video game consoles, video streaming devices (such as content service servers or content distribution servers), broadcast receiver devices, broadcast transmitter devices And so on, and can not use or use any kind of operating system.
  • handheld or stationary devices such as notebook or laptop computers, mobile phones, smartphones, tablets or tablet computers, cameras, desktops Computers, set-top boxes, televisions, cameras, in-vehicle devices, display devices, digital media players, video game consoles, video streaming devices (such as content service servers or content distribution servers), broadcast receiver devices, broadcast transmitter devices And so on, and can not use or use any kind of operating system.
  • Both the encoder 20 and the decoder 30 may be implemented as any of various suitable circuits, for example, one or more microprocessors, digital signal processors (DSPs), application-specific integrated circuits (application-specific integrated circuits) circuit, ASIC), field-programmable gate array (FPGA), discrete logic, hardware, or any combination thereof.
  • DSPs digital signal processors
  • ASIC application-specific integrated circuits
  • FPGA field-programmable gate array
  • the device may store the instructions of the software in a suitable non-transitory computer-readable storage medium, and may use one or more processors to execute the instructions in hardware to perform the techniques of the present disclosure . Any one of the foregoing (including hardware, software, a combination of hardware and software, etc.) may be regarded as one or more processors.
  • the video encoding and decoding system 10 shown in FIG. 1A is only an example, and the technology of the present application may be applied to video encoding settings that do not necessarily include any data communication between encoding and decoding devices (for example, video encoding or video decoding).
  • data may be retrieved from local storage, streamed on the network, and so on.
  • the video encoding device may encode the data and store the data to the memory, and/or the video decoding device may retrieve the data from the memory and decode the data.
  • encoding and decoding are performed by devices that do not communicate with each other but only encode data to and/or retrieve data from memory and decode the data.
  • FIG. 1B is an explanatory diagram of an example of a video coding system 40 including the encoder 20 of FIG. 2 and/or the decoder 30 of FIG. 3 according to an exemplary embodiment.
  • the video decoding system 40 can implement a combination of various technologies in the embodiments of the present application.
  • the video decoding system 40 may include an imaging device 41, an encoder 20, a decoder 30 (and/or a video encoder/decoder implemented by the logic circuit 47 of the processing unit 46), an antenna 42 , One or more processors 43, one or more memories 44, and/or display devices 45.
  • the imaging device 41, the antenna 42, the processing unit 46, the logic circuit 47, the encoder 20, the decoder 30, the processor 43, the memory 44, and/or the display device 45 can communicate with each other.
  • the video coding system 40 is shown with the encoder 20 and the decoder 30, in different examples, the video coding system 40 may include only the encoder 20 or only the decoder 30.
  • antenna 42 may be used to transmit or receive an encoded bitstream of video data.
  • the display device 45 may be used to present video data.
  • the logic circuit 47 may be implemented by the processing unit 46.
  • the processing unit 46 may include application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, and the like.
  • the video decoding system 40 may also include an optional processor 43, which may similarly include application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, and the like.
  • the logic circuit 47 may be implemented by hardware, such as dedicated hardware for video encoding, and the processor 43 may be implemented by general-purpose software, an operating system, and so on.
  • the memory 44 may be any type of memory, such as volatile memory (for example, static random access memory (Static Random Access Memory, SRAM), dynamic random access memory (Dynamic Random Access Memory, DRAM), etc.) or non-volatile Memory (for example, flash memory, etc.), etc.
  • volatile memory for example, static random access memory (Static Random Access Memory, SRAM), dynamic random access memory (Dynamic Random Access Memory, DRAM), etc.
  • non-volatile Memory for example, flash memory, etc.
  • the memory 44 may be implemented by cache memory.
  • the logic circuit 47 can access the memory 44 (eg, to implement an image buffer).
  • the logic circuit 47 and/or the processing unit 46 may include memory (eg, cache, etc.) for implementing image buffers and the like.
  • the encoder 20 implemented by logic circuits may include an image buffer (eg, implemented by the processing unit 46 or the memory 44) and a graphics processing unit (eg, implemented by the processing unit 46).
  • the graphics processing unit may be communicatively coupled to the image buffer.
  • the graphics processing unit may include the encoder 20 implemented by a logic circuit 47 to implement the various modules discussed with reference to FIG. 2 and/or any other encoder system or subsystem described herein.
  • Logic circuits can be used to perform the various operations discussed herein.
  • decoder 30 may be implemented by logic circuit 47 in a similar manner to implement the various modules discussed with reference to decoder 30 of FIG. 3 and/or any other decoder systems or subsystems described herein.
  • the decoder 30 implemented by the logic circuit may include an image buffer (implemented by the processing unit 2820 or the memory 44) and a graphics processing unit (for example, implemented by the processing unit 46).
  • the graphics processing unit may be communicatively coupled to the image buffer.
  • the graphics processing unit may include a decoder 30 implemented by a logic circuit 47 to implement various modules discussed with reference to FIG. 3 and/or any other decoder system or subsystem described herein.
  • antenna 42 may be used to receive an encoded bitstream of video data.
  • the encoded bitstream may include data related to encoded video frames, indicators, index values, mode selection data, etc. discussed herein, such as data related to encoded partitions (eg, transform coefficients or quantized transform coefficients , (As discussed) optional indicators, and/or data defining the code segmentation).
  • the video coding system 40 may also include a decoder 30 coupled to the antenna 42 and used to decode the encoded bitstream.
  • the display device 45 is used to present video frames.
  • the decoder 30 may be used to perform the reverse process.
  • the decoder 30 may be used to receive and parse such syntax elements and decode the relevant video data accordingly.
  • encoder 20 may entropy encode syntax elements into an encoded video bitstream. In such instances, decoder 30 may parse such syntax elements and decode the relevant video data accordingly.
  • the decoding method described in the embodiment of the present application is mainly used in a decoding process, and this process exists in both the encoder 20 and the decoder 30.
  • FIG. 2 shows a schematic/conceptual block diagram of an example of an encoder 20 for implementing an embodiment of the present application.
  • the encoder 20 includes a residual calculation unit 204, a transform processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transform processing unit 212, a reconstruction unit 214, a buffer 216, a loop filter Unit 220, decoded picture buffer (DPB) 230, prediction processing unit 260, and entropy encoding unit 270.
  • the prediction processing unit 260 may include an inter prediction unit 244, an intra prediction unit 254, and a mode selection unit 262.
  • the inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown).
  • the encoder 20 shown in FIG. 2 may also be referred to as a hybrid video encoder or a video encoder based on a hybrid video codec.
  • the residual calculation unit 204, the transform processing unit 206, the quantization unit 208, the prediction processing unit 260, and the entropy encoding unit 270 form the forward signal path of the encoder 20, while, for example, the inverse quantization unit 210, the inverse transform processing unit 212, the heavy
  • the structural unit 214, the buffer 216, the loop filter 220, the decoded picture buffer (DPB) 230, and the prediction processing unit 260 form a backward signal path of the encoder, where the backward signal path of the encoder corresponds The signal path for the decoder (see decoder 30 in FIG. 3).
  • the encoder 20 receives a picture 201 or an image block 203 of the picture 201 through, for example, an input 202, for example, a picture in a picture sequence forming a video or a video sequence.
  • the image block 203 may also be referred to as a current picture block or a picture block to be coded
  • the picture 201 may be referred to as a current picture or a picture to be coded (especially when the current picture is distinguished from other pictures in video coding, other pictures such as the same video sequence That is, the previously encoded and/or decoded pictures in the video sequence of the current picture are also included).
  • An embodiment of the encoder 20 may include a segmentation unit (not shown in FIG. 2) for segmenting the picture 201 into a plurality of blocks such as image blocks 203, usually into a plurality of non-overlapping blocks.
  • the segmentation unit can be used to use the same block size and corresponding grids that define the block size for all pictures in the video sequence, or to change the block size between pictures or subsets or picture groups, and divide each picture into The corresponding block.
  • the prediction processing unit 260 of the encoder 20 may be used to perform any combination of the above-mentioned segmentation techniques.
  • image block 203 is also or can be regarded as a two-dimensional array or matrix of sampling points with sample values, although its size is smaller than picture 201.
  • the image block 203 may include, for example, one sampling array (for example, the brightness array in the case of black and white pictures 201) or three sampling arrays (for example, one brightness array and two chromaticity arrays in the case of color pictures) or An array of any other number and/or category depending on the color format applied.
  • the number of sampling points in the horizontal and vertical directions (or axes) of the image block 203 defines the size of the image block 203.
  • the encoder 20 shown in FIG. 2 is used to encode the picture 201 block by block, for example, to perform encoding and prediction on each image block 203.
  • the residual calculation unit 204 is used to calculate the residual block 205 based on the picture image block 203 and the prediction block 265 (other details of the prediction block 265 are provided below), for example, by subtracting the sample value of the picture image block 203 sample by sample (pixel by pixel) The sample values of the block 265 are depredicted to obtain the residual block 205 in the sample domain.
  • the transform processing unit 206 is used to apply a transform such as discrete cosine transform (DCT) or discrete sine transform (DST) to the sample values of the residual block 205 to obtain transform coefficients 207 in the transform domain .
  • the transform coefficient 207 may also be called a transform residual coefficient, and represents a residual block 205 in the transform domain.
  • the transform processing unit 206 may be used to apply integer approximations of DCT/DST, such as the transform specified by AVS, AVS2, and AVS3. Compared with the orthogonal DCT transform, this integer approximation is usually scaled by a factor. In order to maintain the norm of the residual block processed by the forward and inverse transform, an additional scaling factor is applied as part of the transform process.
  • the scaling factor is usually selected based on certain constraints, for example, the scaling factor is a power of two used for the shift operation, the bit depth of the transform coefficient, the accuracy, and the trade-off between implementation cost, and so on.
  • a specific scaling factor can be specified for the inverse transform by the inverse transform processing unit 212 on the decoder 30 side (and a corresponding inverse transform by the inverse transform processing unit 212 on the encoder 20 side), and accordingly, The 20 side specifies the corresponding scaling factor for the positive transform by the transform processing unit 206.
  • the quantization unit 208 is used to quantize the transform coefficient 207 by, for example, applying scalar quantization or vector quantization to obtain the quantized transform coefficient 209.
  • the quantized transform coefficient 209 may also be referred to as the quantized residual coefficient 209.
  • the quantization process can reduce the bit depth associated with some or all of the transform coefficients 207. For example, n-bit transform coefficients can be rounded down to m-bit transform coefficients during quantization, where n is greater than m.
  • the degree of quantization can be modified by adjusting quantization parameters (QP). For example, for scalar quantization, different scales can be applied to achieve thinner or coarser quantization.
  • QP quantization parameters
  • a smaller quantization step size corresponds to a finer quantization
  • a larger quantization step size corresponds to a coarser quantization.
  • a suitable quantization step size can be indicated by a quantization parameter (QP).
  • the quantization parameter may be an index of a predefined set of suitable quantization steps.
  • smaller quantization parameters may correspond to fine quantization (smaller quantization step size)
  • larger quantization parameters may correspond to coarse quantization (larger quantization step size)
  • the quantization may include dividing by the quantization step size and the corresponding quantization or inverse quantization performed by, for example, inverse quantization 210, or may include multiplying the quantization step size.
  • quantization parameters may be used to determine the quantization step size.
  • the quantization step size can be calculated based on the quantization parameter using a fixed-point approximation including an equation of division. Additional scaling factors can be introduced for quantization and inverse quantization to restore the norm of the residual block that may be modified due to the scale used in fixed-point approximation of the equations for quantization step size and quantization parameter.
  • the scale of inverse transform and inverse quantization may be combined.
  • a custom quantization table can be used and signaled from the encoder to the decoder in a bitstream, for example. Quantization is a lossy operation, where the larger the quantization step, the greater the loss.
  • the inverse quantization unit 210 is used to apply the inverse quantization of the quantization unit 208 on the quantized coefficients to obtain the inverse quantized coefficients 211, for example, based on or using the same quantization step size as the quantization unit 208, apply the quantization scheme applied by the quantization unit 208 Inverse quantization scheme.
  • the inverse quantized coefficient 211 may also be referred to as an inverse quantized residual coefficient 211, which corresponds to the transform coefficient 207, although the loss due to quantization is usually not the same as the transform coefficient.
  • the inverse transform processing unit 212 is used to apply the inverse transform of the transform applied by the transform processing unit 206, for example, an inverse discrete cosine transform (DCT) or an inverse discrete sine transform (DST), in the sample domain
  • the inverse transform block 213 is obtained.
  • the inverse transform block 213 may also be referred to as an inverse transform dequantized block 213 or an inverse transform residual block 213.
  • the reconstruction unit 214 (eg, summer 214) is used to add the inverse transform block 213 (ie, the reconstructed residual block 213) to the prediction block 265 to obtain the reconstructed block 215 in the sample domain, for example, The sample values of the reconstructed residual block 213 and the sample values of the prediction block 265 are added.
  • a buffer unit 216 (or simply "buffer" 216), such as a line buffer 216, is used to buffer or store the reconstructed block 215 and corresponding sample values for, for example, intra prediction.
  • the encoder may be used to use the unfiltered reconstructed blocks and/or corresponding sample values stored in the buffer unit 216 for any type of estimation and/or prediction, such as intra prediction.
  • an embodiment of the encoder 20 may be configured such that the buffer unit 216 is used not only to store the reconstructed block 215 for intra prediction 254, but also for the loop filter unit 220 (not shown in FIG. 2) Out), and/or, for example, causing the buffer unit 216 and the decoded picture buffer unit 230 to form a buffer.
  • Other embodiments may be used to use the filtered block 221 and/or blocks or samples from the decoded picture buffer 230 (neither shown in FIG. 2) as an input or basis for intra prediction 254.
  • the loop filter unit 220 (or simply “loop filter” 220) is used to filter the reconstructed block 215 to obtain the filtered block 221, so as to smoothly perform pixel conversion or improve video quality.
  • the loop filter unit 220 is intended to represent one or more loop filters, such as deblocking filters, sample-adaptive offset (SAO) filters, or other filters, such as bilateral filters, self-adaptive filters Adaptive loop filter (adaptive loop filter, ALF), or sharpening or smoothing filter, or collaborative filter.
  • the loop filter unit 220 is shown as an in-loop filter in FIG. 2, in other configurations, the loop filter unit 220 may be implemented as a post-loop filter.
  • the filtered block 221 may also be referred to as the filtered reconstructed block 221.
  • the decoded picture buffer 230 may store the reconstructed coding block after the loop filter unit 220 performs a filtering operation on the reconstructed coding block.
  • Embodiments of the encoder 20 may be used to output loop filter parameters (eg, sample adaptive offset information), for example, directly output or by the entropy encoding unit 270 or any other
  • the entropy coding unit outputs after entropy coding, for example, so that the decoder 30 can receive and apply the same loop filter parameters for decoding.
  • the decoded picture buffer (DPB) 230 may be a reference picture memory for storing reference picture data for the encoder 20 to encode video data.
  • DPB 230 can be formed by any of a variety of memory devices, such as dynamic random access memory (dynamic random access (DRAM) (including synchronous DRAM (synchronous DRAM, SDRAM), magnetoresistive RAM (magnetoresistive RAM, MRAM), resistive RAM (resistive RAM, RRAM)) or other types of memory devices.
  • DRAM dynamic random access
  • the DPB 230 and the buffer 216 may be provided by the same memory device or separate memory devices.
  • a decoded picture buffer (DPB) 230 is used to store the filtered block 221.
  • the decoded picture buffer 230 may be further used to store other previous filtered blocks of the same current picture or different pictures such as previous reconstructed pictures, such as the previously reconstructed and filtered block 221, and may provide the complete previous The reconstructed ie decoded pictures (and corresponding reference blocks and samples) and/or partially reconstructed current pictures (and corresponding reference blocks and samples), for example for inter prediction.
  • a decoded picture buffer (DPB) 230 is used to store the reconstructed block 215.
  • the prediction processing unit 260 also known as the block prediction processing unit 260, is used to receive or acquire the image block 203 (current image block 203 of the current picture 201) and reconstructed picture data, such as the same (current) picture from the buffer 216 Reference samples and/or reference picture data 231 of one or more previously decoded pictures from the decoded picture buffer 230, and used to process such data for prediction, that is, to provide an inter prediction block 245 or The prediction block 265 of the intra prediction block 255.
  • the mode selection unit 262 may be used to select a prediction mode (eg, intra or inter prediction mode) and/or the corresponding prediction block 245 or 255 used as the prediction block 265 to calculate the residual block 205 and reconstruct the reconstructed block 215.
  • a prediction mode eg, intra or inter prediction mode
  • the corresponding prediction block 245 or 255 used as the prediction block 265 to calculate the residual block 205 and reconstruct the reconstructed block 215.
  • An embodiment of the mode selection unit 262 may be used to select a prediction mode (for example, from those prediction modes supported by the prediction processing unit 260), which provides the best match or the minimum residual (the minimum residual means Better compression in transmission or storage), or provide minimum signaling overhead (minimum signaling overhead means better compression in transmission or storage), or consider or balance both at the same time.
  • the mode selection unit 262 may be used to determine a prediction mode based on rate distortion optimization (RDO), that is, to select a prediction mode that provides minimum bit rate distortion optimization, or to select a prediction mode in which the related rate distortion at least meets the prediction mode selection criteria .
  • RDO rate distortion optimization
  • the encoder 20 is used to determine or select the best or optimal prediction mode from the (predetermined) prediction mode set.
  • the set of prediction modes may include, for example, intra prediction modes and/or inter prediction modes.
  • the intra prediction mode set may include 35 different intra prediction modes, for example, non-directional modes such as DC (or mean) mode and planar mode, or directional modes as defined in H.265, or may include 67 Different intra prediction modes, for example, non-directional modes such as DC (or mean) mode and planar mode, or directional modes as defined in the developing H.266.
  • non-directional modes such as DC (or mean) mode and planar mode
  • directional modes as defined in the developing H.266.
  • the set of inter prediction modes depends on the available reference pictures (ie, for example, the aforementioned at least partially decoded pictures stored in DBP 230) and other inter prediction parameters, for example, depending on whether the entire reference picture is used or only Use a part of the reference picture, for example the search window area surrounding the area of the current block, to search for the best matching reference block, and/or for example depending on whether pixel interpolation such as half-pixel and/or quarter-pixel interpolation is applied
  • the set of inter prediction modes may include advanced motion vector (Advanced Motion Vector Prediction, AMVP) mode and merge mode.
  • AMVP Advanced Motion Vector Prediction
  • the set of inter prediction modes may include the control point-based AMVP mode improved in the embodiment of the present application, and the improved control point-based merge mode.
  • the intra prediction unit 254 may be used to perform any combination of inter prediction techniques described below.
  • the embodiments of the present application may also apply skip mode and/or direct mode.
  • the prediction processing unit 260 may be further used to split the image block 203 into smaller block partitions or sub-blocks, for example, iteratively using quad-tree (QT) segmentation, binary-tree (BT) segmentation Or triple-tree (TT) or extended quad-tree (EQT, Extended Quad-Tree) segmentation, or any combination thereof, and for performing predictions for each of block partitions or sub-blocks, for example, where mode selection This includes selecting the tree structure of the divided image block 203 and selecting the prediction mode applied to each of the block partitions or sub-blocks.
  • QT quad-tree
  • BT binary-tree
  • TT triple-tree
  • EQT Extended Quad-Tree
  • the inter prediction unit 244 may include a motion estimation (ME) unit (not shown in FIG. 2) and a motion compensation (MC) unit (not shown in FIG. 2).
  • the motion estimation unit is used to receive or acquire a picture image block 203 (current picture image block 203 of the current picture 201) and a decoded picture 231, or at least one or more previously reconstructed blocks, for example, one or more other/different
  • the reconstructed block of the previously decoded picture 231 is used for motion estimation.
  • the video sequence may include the current picture and the previously decoded picture 31, or in other words, the current picture and the previously decoded picture 31 may be part of or form a sequence of pictures that form the video sequence.
  • the encoder 20 may be used to select a reference block from multiple reference blocks of the same or different pictures in multiple other pictures, and provide a reference picture and/or provide a reference to a motion estimation unit (not shown in FIG. 2)
  • the offset (spatial offset) between the position of the block (X, Y coordinates) and the position of the current block is used as an inter prediction parameter. This offset is also called motion vector (MV).
  • the motion compensation unit is used to acquire inter prediction parameters and perform inter prediction based on or using inter prediction parameters to obtain inter prediction blocks 245.
  • the motion compensation performed by the motion compensation unit may include extracting or generating a prediction block based on a motion/block vector determined by motion estimation (possibly performing interpolation of sub-pixel accuracy). Interpolation filtering can generate additional pixel samples from known pixel samples, potentially increasing the number of candidate prediction blocks that can be used to encode picture blocks.
  • the motion compensation unit 246 may locate the prediction block pointed to by the motion vector in a reference picture list. Motion compensation unit 246 may also generate syntax elements associated with blocks and video slices for use by decoder 30 when decoding picture blocks of video slices.
  • the above inter prediction unit 244 may transmit a syntax element to the entropy encoding unit 270, where the syntax element includes inter prediction parameters (such as an inter prediction mode selected for the current block prediction after traversing multiple inter prediction modes Instructions).
  • inter prediction parameters such as an inter prediction mode selected for the current block prediction after traversing multiple inter prediction modes Instructions.
  • the decoding terminal 30 may directly use the default prediction mode for decoding. It can be understood that the inter prediction unit 244 may be used to perform any combination of inter prediction techniques.
  • the intra prediction unit 254 is used to acquire, for example, a picture block 203 (current picture block) that receives the same picture and one or more previously reconstructed blocks, such as reconstructed neighboring blocks, for intra estimation.
  • the encoder 20 may be used to select an intra prediction mode from a plurality of (predetermined) intra prediction modes.
  • Embodiments of the encoder 20 may be used to select an intra prediction mode based on optimization criteria, for example, based on a minimum residual (eg, an intra prediction mode that provides the prediction block 255 most similar to the current picture block 203) or minimum rate distortion.
  • a minimum residual eg, an intra prediction mode that provides the prediction block 255 most similar to the current picture block 203
  • minimum rate distortion e.g., a minimum rate distortion
  • the intra prediction unit 254 is further used to determine the intra prediction block 255 based on the intra prediction parameters of the intra prediction mode as selected. In any case, after selecting the intra-prediction mode for the block, the intra-prediction unit 254 is also used to provide the intra-prediction parameters to the entropy encoding unit 270, that is, to provide an indication of the selected intra-prediction mode for the block Information. In one example, the intra prediction unit 254 may be used to perform any combination of intra prediction techniques.
  • the above-mentioned intra-prediction unit 254 may transmit a syntax element to the entropy encoding unit 270, where the syntax element includes intra-prediction parameters (such as the intra-prediction mode selected for the current block prediction after traversing multiple intra-prediction modes) Instructions).
  • the intra prediction parameters may not be carried in the syntax element.
  • the decoding terminal 30 may directly use the default prediction mode for decoding.
  • the entropy coding unit 270 is used to convert the entropy coding algorithm or scheme (for example, variable length coding (VLC) scheme, context adaptive VLC (context adaptive VLC, CAVLC) scheme, arithmetic coding scheme, context adaptive binary arithmetic) Encoding (context adaptive) binary arithmetic coding (CABAC), syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval entropy (probability interval interpartitioning entropy, PIPE) encoding or other entropy Coding method or technique) applied to a single or all of the quantized residual coefficients 209, inter prediction parameters, intra prediction parameters, and/or loop filter parameters (or not applied) to obtain the output 272 to For example, the encoded picture data 21 output in the form of an encoded bit stream 21.
  • VLC variable length coding
  • CABAC context adaptive binary arithmetic
  • SBAC syntax-based context-adaptive binary arithmetic coding
  • the encoded bitstream can be transmitted to the video decoder 30 or archived for later transmission or retrieval by the video decoder 30.
  • the entropy encoding unit 270 may also be used to entropy encode other syntax elements of the current video slice being encoded.
  • video encoder 20 may be used to encode video streams.
  • the non-transform based encoder 20 may directly quantize the residual signal without the transform processing unit 206 for certain blocks or frames.
  • the encoder 20 may have a quantization unit 208 and an inverse quantization unit 210 combined into a single unit.
  • the encoder 20 may be used to implement the encoding method described in the following embodiments.
  • the video encoder 20 can directly quantize the residual signal without processing by the transform processing unit 206, and accordingly, without processing by the inverse transform processing unit 212; or, for some For image blocks or image frames, the video encoder 20 does not generate residual data, and accordingly does not need to be processed by the transform processing unit 206, quantization unit 208, inverse quantization unit 210, and inverse transform processing unit 212; or, the video encoder 20 may convert The reconstructed image block is directly stored as a reference block without being processed by the filter 220; alternatively, the quantization unit 208 and the inverse quantization unit 210 in the video encoder 20 may be merged together.
  • the loop filter 220 is optional, and in the case of lossless compression encoding, the transform processing unit 206, quantization unit 208, inverse quantization unit 210, and inverse transform processing unit 212 are optional. It should be understood that the inter prediction unit 244 and the intra prediction unit 254 may be selectively enabled according to different application scenarios.
  • FIG. 3 shows a schematic/conceptual block diagram of an example of a decoder 30 for implementing an embodiment of the present application.
  • the video decoder 30 is used to receive encoded picture data (eg, encoded bitstream) 21, for example, encoded by the encoder 20, to obtain the decoded picture 231.
  • encoded picture data eg, encoded bitstream
  • video decoder 30 receives video data from video encoder 20, such as an encoded video bitstream and associated syntax elements representing picture blocks of the encoded video slice.
  • the decoder 30 includes an entropy decoding unit 304, an inverse quantization unit 310, an inverse transform processing unit 312, a reconstruction unit 314 (such as a summer 314), a buffer 316, a loop filter 320, a The decoded picture buffer 330 and the prediction processing unit 360.
  • the prediction processing unit 360 may include an inter prediction unit 344, an intra prediction unit 354, and a mode selection unit 362.
  • video decoder 30 may perform a decoding pass that is generally inverse to the encoding pass described with reference to video encoder 20 of FIG. 2.
  • the entropy decoding unit 304 is used to perform entropy decoding on the encoded picture data 21 to obtain, for example, quantized coefficients 309 and/or decoded encoding parameters (not shown in FIG. 3), for example, inter prediction, intra prediction parameters , Any or all of the loop filter parameters and/or other syntax elements (decoded).
  • the entropy decoding unit 304 is further used to forward inter prediction parameters, intra prediction parameters, and/or other syntax elements to the prediction processing unit 360.
  • Video decoder 30 may receive syntax elements at the video slice level and/or the video block level.
  • the inverse quantization unit 310 may be functionally the same as the inverse quantization unit 110
  • the inverse transform processing unit 312 may be functionally the same as the inverse transform processing unit 212
  • the reconstruction unit 314 may be functionally the same as the reconstruction unit 214
  • the buffer 316 may be functionally
  • the loop filter 320 may be functionally the same as the loop filter 220
  • the decoded picture buffer 330 may be functionally the same as the decoded picture buffer 230.
  • the prediction processing unit 360 may include an inter prediction unit 344 and an intra prediction unit 354, where the inter prediction unit 344 may be similar in function to the inter prediction unit 244, and the intra prediction unit 354 may be similar in function to the intra prediction unit 254 .
  • the prediction processing unit 360 is generally used to perform block prediction and/or obtain the prediction block 365 from the encoded data 21, and to receive or obtain prediction-related parameters and/or information about the entropy decoding unit 304 (explicitly or implicitly). Information about the selected prediction mode.
  • the intra prediction unit 354 of the prediction processing unit 360 is used to signal-based the intra prediction mode and the previous decoded block from the current frame or picture Data to generate a prediction block 365 for the picture block of the current video slice.
  • the inter prediction unit 344 eg, motion compensation unit
  • Other syntax elements generate a prediction block 365 for the video block of the current video slice.
  • a prediction block may be generated from a reference picture in a reference picture list.
  • the video decoder 30 may construct the reference frame lists: list 0 and list 1 based on the reference pictures stored in the DPB 330 using default construction techniques.
  • the prediction processing unit 360 is used to determine the prediction block for the video block of the current video slice by parsing the motion vector and other syntax elements, and use the prediction block to generate the prediction block for the current video block being decoded.
  • the prediction processing unit 360 uses some received syntax elements to determine the prediction mode (eg, intra or inter prediction) of the video block used to encode the video slice, and the inter prediction slice type ( For example, B slice, P slice, or GPB slice), construction information for one or more of the reference picture lists for slices, motion vectors for each inter-coded video block for slices, The inter prediction status and other information of each inter-coded video block of the slice to decode the video block of the current video slice.
  • the prediction mode eg, intra or inter prediction
  • the inter prediction slice type For example, B slice, P slice, or GPB slice
  • the syntax elements received by the video decoder 30 from the bitstream include an adaptive parameter set (adaptive parameter set, APS), a sequence parameter set (SPS), and a picture parameter set (picture parameter (set, PPS) or the syntax element in one or more of the stripe headers.
  • an adaptive parameter set adaptive parameter set
  • SPS sequence parameter set
  • PPS picture parameter set
  • the inverse quantization unit 310 may be used to inverse quantize (ie, inverse quantize) the quantized transform coefficients provided in the bitstream and decoded by the entropy decoding unit 304.
  • the inverse quantization process may include using the quantization parameters calculated by the video encoder 20 for each video block in the video slice to determine the degree of quantization that should be applied and also determine the degree of inverse quantization that should be applied.
  • the inverse transform processing unit 312 is used to apply an inverse transform (eg, inverse DCT, inverse integer transform, or conceptually similar inverse transform process) to the transform coefficients to generate a residual block in the pixel domain.
  • an inverse transform eg, inverse DCT, inverse integer transform, or conceptually similar inverse transform process
  • the reconstruction unit 314 (eg, summer 314) is used to add the inverse transform block 313 (ie, the reconstructed residual block 313) to the prediction block 365 to obtain the reconstructed block 315 in the sample domain, for example by The sample values of the reconstructed residual block 313 and the sample values of the prediction block 365 are added.
  • the loop filter unit 320 (during the encoding cycle or after the encoding cycle) is used to filter the reconstructed block 315 to obtain the filtered block 321 to smoothly perform pixel conversion or improve video quality.
  • the loop filter unit 320 may be used to perform any combination of filtering techniques described below.
  • the loop filter unit 320 is intended to represent one or more loop filters, such as deblocking filters, sample-adaptive offset (SAO) filters, or other filters, such as bilateral filters, Adaptive loop filter (adaptive loop filter, ALF), or sharpening or smoothing filter, or collaborative filter.
  • the loop filter unit 320 is shown as an in-loop filter in FIG. 3, in other configurations, the loop filter unit 320 may be implemented as a post-loop filter.
  • the decoded video block 321 in a given frame or picture is then stored in a decoded picture buffer 330 that stores reference pictures for subsequent motion compensation.
  • the decoder 30 is used, for example, to output the decoded picture 31 through the output 332 for presentation to the user or for the user to view.
  • video decoder 30 may be used to decode the compressed bitstream.
  • the decoder 30 may generate the output video stream without the loop filter unit 320.
  • the non-transform based decoder 30 may directly inversely quantize the residual signal without the inverse transform processing unit 312 for certain blocks or frames.
  • the video decoder 30 may have an inverse quantization unit 310 and an inverse transform processing unit 312 combined into a single unit.
  • the decoder 30 is used to implement the decoding method described in the embodiments below.
  • the block division operation may be performed by the prediction processing unit 360 or by an independent unit (not shown in the figure).
  • the prediction processing unit 360 may be used to split the image block 203 into smaller block partitions or sub-blocks, for example, by iteratively using quad-tree (QT) segmentation, binary-tree (BT) segmentation or Triple-tree (TT) or extended quad-tree (EQT, Extended-Quad-Tree) segmentation, or any combination thereof, the partitioning method can be determined based on preset rules or based on parsed syntax for indicating the partitioning method Element determination, and for performing prediction, for example, for each of the block partitions or sub-blocks, where mode selection includes selecting a tree structure of the divided image block 203 and selecting a prediction mode applied to each of the block partitions or sub-blocks.
  • QT quad-tree
  • BT binary-tree
  • TT Triple-tree
  • EQT Extended-Quad-Tree
  • video decoder 30 may be used to decode the encoded video bitstream.
  • the video decoder 30 may generate an output video stream without processing by the filter 320; or, for some image blocks or image frames, the entropy decoding unit 304 of the video decoder 30 does not decode the quantized coefficients, and accordingly does not It needs to be processed by the inverse quantization unit 310 and the inverse transform processing unit 312.
  • the loop filter 320 is optional; and for lossless compression, the inverse quantization unit 310 and the inverse transform processing unit 312 are optional.
  • the inter prediction unit and the intra prediction unit may be selectively enabled.
  • the processing results for a certain link can be further processed and output to the next link, for example, in interpolation filtering, motion vector derivation or loop filtering, etc. After the link, the results of the corresponding link are further clipped or shift shifted.
  • the motion vectors of the control points of the current image block derived from the motion vectors of adjacent affine coding blocks, or the motion vectors of the sub-blocks of the current image block derived may be further processed, and this application does not do this limited.
  • the value range of the motion vector is constrained to be within a certain bit width. Assuming that the allowed bit width of the motion vector is bitDepth, the range of the motion vector is -2 ⁇ (bitDepth-1) ⁇ 2 ⁇ (bitDepth-1)-1, where the " ⁇ " symbol indicates a power. If bitDepth is 16, the value ranges from -32768 to 32767. If bitDepth is 18, the value ranges from -131072 to 131071.
  • the values of the motion vectors are constrained so that the maximum difference between the integer parts of the four 4x4 sub-blocks MV does not exceed N pixels, for example no more than one pixel.
  • ux (vx+2 bitDepth )%2 bitDepth
  • vx is the horizontal component of the motion vector of the image block or the sub-block of the image block
  • vy is the vertical component of the motion vector of the image block or the sub-block of the image block
  • ux and uy are intermediate values
  • bitDepth represents the bit width
  • the value of vx is -32769, and 32767 is obtained by the above formula. Because in the computer, the value is stored in the form of two's complement, the complement of -32769 is 1,0111,1111,1111,1111 (17 bits), the computer handles the overflow as discarding the high bit, then the value of vx If it is 0111,1111,1111,1111, it is 32767, which is consistent with the result obtained by formula processing.
  • vx Clip3(-2bitDepth-1,2bitDepth-1-1,vx)
  • vx is the horizontal component of the motion vector of the image block or the sub-block of the image block
  • vy is the vertical component of the motion vector of the image block or the sub-block of the image block
  • x, y, and z respectively correspond to the MV clamp
  • FIG. 4 is a schematic structural diagram of a video decoding device 400 (for example, a video encoding device 400 or a video decoding device 400) provided by an embodiment of the present application.
  • the video coding device 400 is suitable for implementing the embodiments described herein.
  • the video coding device 400 may be a video decoder (eg, decoder 30 of FIG. 1A) or a video encoder (eg, encoder 20 of FIG. 1A).
  • the video decoding device 400 may be one or more components in the decoder 30 of FIG. 1A or the encoder 20 of FIG. 1A described above.
  • the video decoding apparatus 400 includes: an inlet port 410 for receiving data and a receiving unit (Rx) 420, a processor for processing data, a logic unit or a central processing unit (CPU) 430, and a transmitter unit for transmitting data (Tx) 440 and exit port 450, and a memory 460 for storing data.
  • the video decoding device 400 may further include a photoelectric conversion component and an electro-optical (EO) component coupled to the inlet port 410, the receiver unit 420, the transmitter unit 440, and the outlet port 450 for the outlet or inlet of the optical signal or the electrical signal.
  • EO electro-optical
  • the processor 430 is implemented by hardware and software.
  • the processor 430 may be implemented as one or more CPU chips, cores (eg, multi-core processors), FPGA, ASIC, and DSP.
  • the processor 430 communicates with the inlet port 410, the receiver unit 420, the transmitter unit 440, the outlet port 450, and the memory 460.
  • the processor 430 includes a decoding module 470 (for example, an encoding module 470 or a decoding module 470).
  • the encoding/decoding module 470 implements the embodiments disclosed herein to implement the chroma block prediction method provided by the embodiments of the present application. For example, the encoding/decoding module 470 implements, processes, or provides various encoding operations.
  • the encoding/decoding module 470 provides a substantial improvement in the function of the video decoding device 400 and affects the conversion of the video decoding device 400 to different states.
  • the encoding/decoding module 470 is implemented with instructions stored in the memory 460 and executed by the processor 430.
  • the memory 460 includes one or more magnetic disks, tape drives, and solid-state drives, and can be used as an overflow data storage device for storing programs when these programs are selectively executed, as well as instructions and data read during program execution.
  • the memory 460 may be volatile and/or non-volatile, and may be read only memory (ROM), random access memory (RAM), random access memory (ternary content-addressable memory (TCAM), and/or static Random Access Memory (SRAM).
  • FIG. 5 is a simplified block diagram of an apparatus 500 that can be used as either or both of the source device 12 and the destination device 14 in FIG. 1A according to an exemplary embodiment.
  • the device 500 can implement the technology of the present application.
  • FIG. 5 is a schematic block diagram of an implementation manner of an encoding device or a decoding device (referred to simply as a decoding device 500) according to an embodiment of the present application.
  • the decoding device 500 may include a processor 510, a memory 530, and a bus system 550.
  • the processor and the memory are connected through a bus system, the memory is used to store instructions, and the processor is used to execute the instructions stored in the memory.
  • the memory of the decoding device stores the program code, and the processor can call the program code stored in the memory to perform various video encoding or decoding methods described in this application, especially various new decoding methods. In order to avoid repetition, they are not described in detail here.
  • the processor 510 may be a central processing unit (Central Processing Unit, referred to as "CPU"), and the processor 510 may also be other general-purpose processors, digital signal processors (DSPs), dedicated integrated Circuit (ASIC), ready-made programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.
  • the general-purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
  • the memory 530 may include a read-only memory (ROM) device or a random access memory (RAM) device. Any other suitable type of storage device may also be used as the memory 530.
  • the memory 530 may include code and data 531 accessed by the processor 510 using the bus 550.
  • the memory 530 may further include an operating system 533 and an application program 535 including at least one program that allows the processor 510 to perform the video encoding or decoding method described in the present application (in particular, the decoding method described in the present application).
  • the application program 535 may include applications 1 to N, which further include a video encoding or decoding application (referred to as a video decoding application) that performs the video encoding or decoding method described in this application.
  • the bus system 550 may also include a power bus, a control bus, and a status signal bus. However, for clarity, various buses are marked as the bus system 550 in the figure.
  • the decoding device 500 may also include one or more output devices, such as a display 570.
  • the display 570 may be a tactile display that merges the display with a tactile unit that operably senses touch input.
  • the display 570 may be connected to the processor 510 via the bus 550.
  • the video coding standard divides a frame of images into non-overlapping coding tree units (CTU).
  • the size of the CTU can be set to 64 ⁇ 64 (the size of the CTU can also be set to other values, such as the CTU size increased to 128 ⁇ 128 or 256 ⁇ 256, etc.).
  • a 64 ⁇ 64 CTU contains a rectangular pixel lattice of 64 columns with 64 pixels in each column, and each pixel contains a luminance component or/and a chrominance component.
  • CTU coding tree unit (coding tree unit), an image is composed of multiple CTUs, a CTU usually corresponds to a square image area, including the brightness pixels and chrominance pixels in the image area (or may only contain brightness pixels , Or it may only contain chroma pixels); CTU also contains syntax elements that indicate how to divide the CTU into at least one coding unit (CU), and a method of decoding each coding unit to obtain a reconstructed image.
  • CU coding unit
  • CU coding unit, usually corresponding to an A ⁇ B rectangular area, containing A ⁇ B luminance pixels and its corresponding chrominance pixels, A is the width of the rectangle, B is the height of the rectangle, A and B may be the same or different
  • the values of A and B are usually integer powers of 2, such as 256, 128, 64, 32, 16, 8, and 4.
  • An encoding unit can decode to obtain a reconstructed image of an A ⁇ B rectangular area through decoding.
  • the decoding process usually includes prediction, inverse quantization, and inverse transform to generate a predicted image and a residual. The predicted image and the residual are superimposed and reconstructed. image.
  • Quad-tree A tree-like structure in which a node can be divided into four child nodes.
  • the video coding standard adopts the CTU division method based on the quadtree: CTU is used as the root node, each node corresponds to a square area, that is, the square area is divided into four square areas of the same size (the length and width are divided respectively) Half of the front area length and width), each area corresponds to a node, as shown in Figure 6 (a).
  • a node can no longer be divided (at this time its corresponding area is a CU), or it can be divided into the next level of nodes in the manner of QT, BT, TT or EQT.
  • Binary tree (BT, Binary Tree): A tree structure, a node can be divided into two child nodes. There are two ways to divide into two nodes: 1) Horizontal dichotomy, divide the area corresponding to the node into two areas of the same size, the top and the bottom, each area corresponds to a node, as shown in Figure 6(b); Or 2) Vertical dichotomy, divide the area corresponding to the node into two areas of the same size on the left and right, each area corresponds to a node, as shown in Figure 6(c).
  • a node on a binary tree structure may not be divided (in this case, the corresponding area is a CU), or the node may be further divided into nodes at the next level according to BT, TT, or EQT.
  • Ternary tree a tree structure
  • a node can be divided into three child nodes.
  • a node on a tri-tree structure may not be divided, or the node may be divided into three nodes at the next level.
  • a node on a trigeminal tree structure may not be divided (in this case, the corresponding area is a CU), or the node may be further divided into the next level according to BT, TT, or EQT. node.
  • Extended quad-tree A structure of I-shaped division, a node can be divided into four sub-nodes. There are two ways to divide into three nodes: 1) Horizontal quartering, divide the area corresponding to the node into three areas: upper, middle, and lower, each area corresponds to a node, of which upper, middle left, middle right, The heights of the next three areas are 1/4, 1/2, 1/2, 1/4 of the node height, and the widths of the middle left and right are 1/2, 1/2 of the height of the node, as shown in Figure 6(f ) As shown; or 2) vertical quartering, the area corresponding to the node is divided into three areas of left, middle upper, middle lower, and right, each area corresponds to a node, and the three areas of left, middle and right The widths are 1/4, 1/2, 1/2, and 1/4 of the node height, respectively, and the upper, middle, and lower widths are 1/2 and 1/2 of the node height, as shown in Figure 6(g). In the following ways to divide into three nodes: 1) Horizontal
  • Video decoding (video decoding): the process of restoring the video stream to a reconstructed image according to specific grammar rules and processing methods.
  • Video encoding The process of compressing an image sequence into a code stream
  • Video encoding The general term for video encoding and video decoding.
  • the Chinese translation is the same as video encoding.
  • VTM New codec reference software developed by JVET.
  • the video coding standard divides a frame of images into non-overlapping coding tree units (CTU).
  • the size of the CTU can be set to 64 ⁇ 64 (the size of the CTU can also be set to other values, such as the CTU size increased to 128 ⁇ 128 or 256 ⁇ 256, etc.).
  • a 64 ⁇ 64 CTU contains a rectangular pixel lattice of 64 columns with 64 pixels in each column, and each pixel contains a luminance component or/and a chrominance component.
  • the CTU is used as the root node of the quad-tree, and the CTU is recursively divided into several leaf nodes (leaf) according to the quad-tree division method node).
  • a node corresponds to an image area. If the node is not divided, the node is called a leaf node, and the corresponding image area forms a CU; if the node continues to be divided, the image area corresponding to the node is divided into four areas of the same size (which The length and width are each half of the divided area), each area corresponds to a node, you need to determine whether these nodes will be divided.
  • Whether a node is divided is indicated by the split flag bit split_cu_flag corresponding to this node in the code stream.
  • the quad-tree level (qtDepth) of the root node is 0, and the quad-tree level of the child node is +1 of the quad-tree level of the parent node.
  • the size and shape of the node in the following refers to the size and shape of the image area corresponding to the node.
  • the leaf node When a node is parsed as a leaf node, the leaf node is a CU, and further parses the coding information corresponding to the CU (including CU prediction mode, transform coefficients and other information, such as coding_unit () syntax structure), and then according to these coding information Perform decoding processing such as prediction, inverse quantization, inverse transform, and loop filtering on the CU to generate a reconstructed image corresponding to the CU.
  • the quadtree structure allows the CTU to be divided into a group of CUs of appropriate size according to the local characteristics of the image, for example, smooth regions are divided into larger CUs, and texture-rich regions are divided into smaller CUs.
  • a CTU divided into a group of CUs corresponds to a coding tree (coding tree).
  • the coding tree that the CTU should use is usually determined by the rate-distortion optimization (RDO) technology of the encoder.
  • RDO rate-distortion optimization
  • the encoder tries a variety of CTU division methods, each of which corresponds to a rate-distortion cost (RD cost); the encoder compares the RD costs of various tried division methods and finds the division method with the smallest RD cost as the CTU
  • the optimal division method is used for the actual coding of the CTU.
  • the various CTU division methods tried by the encoder need to comply with the division rules specified by the decoder, so that these can be correctly recognized by the decoder.
  • Intra Block Copy is an intra prediction technique that looks for the same block in the current screen content.
  • the syntax element pred_mode_ibc_flag described in Table 2 may be used to indicate whether the current coding unit uses the IBC prediction mode.
  • BT binary tree
  • EQT extended quad-tree
  • Binary tree division divides a node into two child nodes. There are two specific ways to divide a binary tree:
  • Extended quadtree division divides a node into four sub-nodes. There are two specific ways to expand a quadtree:
  • the area corresponding to the node is divided into three areas: left, middle upper, middle lower, and right, each area corresponds to a node, and the width of the left, middle, and right areas is the height of the node. 1/4, 1/2, 1/2, 1/4, the upper middle and lower width are 1/2, 1/2 of the node height, as shown in Figure 6(g).
  • the QT cascade BT/EQT division method that is, the nodes on the first-level coding tree can only be divided into child nodes using QT, the leaf nodes of the first-level coding tree are the root nodes of the second-level coding tree; the second-level coding tree The nodes on can be divided into child nodes using one of the BT or EQT division methods; the leaf nodes of the second-level coding tree are coding units. It should be noted that when the leaf node is BT or EQT, the leaf node can only use BT or EQT, but not QT.
  • Binary tree division divides a node into two child nodes. There are two specific ways to divide a binary tree:
  • the trigeminal tree division divides a node into two sub-nodes. There are two specific ways to divide the bifurcation tree:
  • Horizontal three-point divide the area corresponding to the node into three areas: upper, middle, and lower, each area corresponds to a node, and the heights of the upper, middle, and lower areas are 1/4, 1/ 1 of the height of the node, respectively 2, 1/4, as shown in Figure 6(d);
  • the area corresponding to the node is divided into left, center and right areas, each area corresponds to a node, and the width of the left, center and right areas is 1/4 and 1 of the node height respectively /2, 1/4, as shown in Figure 6(e)
  • QT cascade BT/TT division method referred to as QT-BTT
  • the nodes on the first level coding tree can only be divided into child nodes using QT
  • the leaf nodes of the first level coding tree are the root nodes of the second level coding tree
  • the nodes on the second-level coding tree can be divided into child nodes using one of the four division methods: horizontal dichotomy, vertical dichotomy, horizontal trisection, and vertical trisection; the leaf nodes of the second-level coding tree are encoding unit.
  • Part of the CU-level syntax structure can be shown in Table 1. If the current node is no longer divided into child nodes, the current node is the coding unit, and the prediction block of the coding unit is parsed according to the following syntax structure.
  • skip_flag is a flag of skip mode
  • a value of 1 indicates that the current CU uses the skip mode
  • a value of 0 indicates that the current CU does not use the skip mode.
  • merge_flag is a direct mode flag. A value of 1 indicates that the current CU uses the merge mode; a value of 0 indicates that the merge mode is not used.
  • cu_pred_mode is the coding unit prediction mode flag. A value of 1 indicates that the current prediction unit uses the intra prediction mode; a value of 0 indicates that the current prediction unit uses the normal inter prediction mode.
  • Table 2 is just an example, in which the meaning of skip_flag in Table 1 is the same, and the meaning of pred_mode_flag is the same as the meaning of cu_pred_mode in Table 1.
  • cu_skip_flag is a flag of skip mode, a value of 1 indicates that the current CU uses the skip mode, and a value of 0 indicates that the current CU does not use the skip mode.
  • general_merge_flag is the fusion mode flag. A value of 1 indicates that the current CU uses the fusion mode; a value of 0 indicates that the fusion mode is not used.
  • pred_mode_flag is a coding unit prediction mode flag. A value of 1 indicates that the current coding unit uses the intra prediction mode; a value of 0 indicates that the current coding unit uses the normal inter prediction mode. If pred_mode_flag is 1, CuPredMode[x0][y0] is CuPredMode[x0][y0] is MODE_INTRA; if pred_mode_flag is 0, CuPredMode[x0][y0] is MODE_INTER.
  • pred_mode_ibc_flag When pred_mode_ibc_flag is 1, it indicates that the current coding unit uses the IBC prediction mode, and a value of 0 indicates that the current coding unit does not use the IBC prediction mode. If pred_mode_ibc_flag is 1, then CuPredMode[x0][y0] is MODE_IBC.
  • CuPredMode[x0][y0] represents the prediction mode of the current coding unit
  • (x0, y0) represents the position of the current coding unit in the current image.
  • An 8xM (or Mx8) size node is divided into two nodes of 4xM (or Mx4) size using vertical bisection (or horizontal dichotomy); similarly, a 16xM (or Mx16) size node uses vertical expansion of four After dividing (or horizontally expanding by four points), four 4xM (or Mx4) child nodes and one 8xN (or Nx8) child node will be generated. Similarly, when a 16xM (or Mx16) size node is divided by a vertical three-point (or horizontal three-point), two 4xM (or Mx4) child nodes and an 8xM (or Nx8) child node will be generated.
  • the resolution of the chroma component is 1/2 of the luma component, that is, a 4xM node contains a 4xM luma block and two 2x (M/2) chroma blocks.
  • the processing cost of small blocks is relatively high.
  • this division method will produce 2x2, 2x4 and other small blocks, which is not conducive to the implementation of hardware decoders.
  • the processing complexity of the small block is relatively high, specifically including the following three aspects.
  • Intra prediction problem In order to improve the processing speed in hardware design, intra prediction usually processes 16 pixels at a time, while 2x2, 2x4, 4x2 and other small blocks contain less than 16 pixels, which reduces the processing performance of intra prediction .
  • Coefficient coding problem The transform coefficient coding in HEVC is based on a coefficient group (CG) containing 16 coefficients, and the small blocks of 2x2, 2x4, and 4x2 contain 4 or 8 transform coefficients, which leads to the need to increase the inclusion
  • the coefficient groups of 4 coefficients and 8 coefficients support the coding of these small blocks, thus increasing the complexity of implementation.
  • Inter-frame prediction of small blocks requires high data bandwidth and also affects the processing speed of decoding.
  • a node uses a division method to continue division and one of the child nodes contains a chroma block with a side length of 2, then the brightness block contained in the child node continues to be divided using this division.
  • the included chroma blocks are no longer divided. In this way, it is possible to avoid the generation of chroma blocks with a side length of 2, reducing the maximum throughput of the decoder, which is beneficial to the decoder.
  • a method for determining the chroma block prediction mode according to the luma block prediction mode is proposed, which effectively improves the coding efficiency.
  • the image prediction method provided by the present application can be applied to the video encoder 18 or the video decoder 24 shown in FIG. 8. It should be noted that the individual steps in the following embodiments are only performed in the video decoder 24, and the corresponding positions in the following will be specifically described.
  • FIG. 9 is a schematic flowchart of a first image prediction method provided by an embodiment of the present application.
  • the image prediction method provided by this embodiment includes the following steps:
  • Step 101 Obtain the division mode of the current node.
  • the division information of the current node is analyzed, and the division information is used to indicate whether to divide the current node or not. If the division information indicates to divide the current node, obtain the division mode of the current node.
  • the current node division method includes at least one of quadtree division, vertical bisection, horizontal bisection, vertical trisection, and horizontal trisection. Of course, it may be other division modes, which is not specifically limited in this embodiment. .
  • the division information of the current node can be transmitted in the code stream. By parsing the corresponding syntax element in the code stream, the division information of the current node can be parsed and the specific division method can be determined.
  • the current node division method can also be determined based on other preset rules, which is not specifically limited in this embodiment.
  • the split information specifically includes the way to split the luminance block included in the current node, and/or the chroma included in the current node How the blocks are divided.
  • the manner of dividing the luminance block included in the current node and the manner of dividing the chrominance block included in the current node may be the same or different, and this embodiment is not specifically limited.
  • the division information is used to indicate that a quadtree division is used for both the luma block and the chroma block of the current node.
  • the division information is used to indicate that a quadtree division is used for the luma block of the current node, and vertical dichotomy is used for the chroma block of the current node.
  • Step 102 Determine whether dividing the current node based on the dividing mode will obtain an image block with a preset size.
  • the image block with a preset size may be a brightness block with a size smaller than a threshold, and the threshold may be 128, 64, or 32 luma sampling points, or 32, 16, or 8 chroma sampling points.
  • the size of the current node may be greater than or equal to the threshold.
  • step 103 is performed; in the case where it is determined that dividing the current node based on the division mode will not result in an image block with a preset size ,Go to step 104.
  • Step 103 Use intra prediction for all coding blocks covered by the current node, or use inter prediction for all coding blocks covered by the current node.
  • the current node in this embodiment may be understood as an image area or image block corresponding to the node to be processed or divided. All code blocks covered by the current node can be understood as all code blocks located in the current node area. All coding blocks in this embodiment include a luma coding block and a chroma coding block that are divided or not divided for the current node. Among them, the coding block may also be a coding unit (coding unit).
  • the intra prediction can be performed using a normal intra prediction mode (intra mode) for prediction, or an IBC (intra block copy) mode for prediction.
  • intra mode normal intra prediction mode
  • IBC intra block copy
  • intra prediction is used for all coding blocks covered by the current node instead of inter prediction.
  • using intra prediction on all coding blocks covered by the current node may include:
  • the luminance block of the current node is divided according to the division method of the luminance block to obtain N luminance coding tree nodes; the chroma block of the current node is not Divide and get a chroma coding block (referred to as chroma CB)
  • the N luminance coding tree nodes can be restricted to not continue to be divided, or do not make this restriction. If the luminance coding tree node continues to be divided, then the division method is analyzed to recursively divide. When the luminance coding tree node is no longer divided, it corresponds to a luminance coding block (abbreviated as luminance CB).
  • luminance CB a luminance coding block
  • the luma CB uses intra prediction to obtain a luma prediction block corresponding to the luma CB.
  • the chroma CB uses intra prediction to obtain a chroma prediction block corresponding to the chroma CB, and the size of the chroma prediction block and the chroma CB are the same.
  • using inter prediction on all coding blocks covered by the current node may include:
  • the luminance block of the current node is divided according to the division method of the luminance block to obtain N luminance coding tree nodes; the chroma block of the current node is not Divide and get a chroma coding block (referred to as chroma CB)
  • the luminance block included in the current node is divided according to the division mode of the current node,
  • the chroma block of the current node is no longer divided.
  • using inter prediction on all coding blocks covered by the current node may include:
  • the luminance block of the current node is divided according to the division method of the luminance block to obtain N luminance coding tree nodes;
  • the chroma block is divided into ways to obtain M chroma coding tree nodes.
  • N and M are positive integers, and N and M may be the same or different.
  • the division may not be continued, or the restriction is not made.
  • N luma coding tree nodes correspond to N luma CBs of the current node
  • M chroma coding tree nodes correspond to M chroma CBs of the current node.
  • N luma CBs use inter prediction to obtain corresponding luma prediction blocks
  • M chroma CBs use inter prediction to obtain corresponding chroma prediction blocks.
  • using inter prediction for all coding blocks covered by the current node may include:
  • the subnodes include the luma block and the chroma block. Determine whether to divide the subnodes of the current node based on the subdivision mode to obtain the luma block with the first preset size; In the case where the sub-nodes of the current node are divided by the sub-division method to obtain a brightness block having the first preset size, the sub-nodes of the current node are divided by a division method other than the sub-division method to obtain the corresponding coding block , And use inter prediction for the corresponding coding block, or use the inter prediction of the child node of the current node as the coding block.
  • the child node is divided according to the child node division method of the current node, a luminance block with a first preset size (4x4) is generated, then the child node division method is not allowed, or, the The child nodes cannot continue to be divided, or the child nodes can be divided using a division method other than the sub division method. For example, if the size of the current node is 8x8 and the horizontal binary tree (or vertical binary tree) division is used to produce two 8x4 (or two 4x8) nodes, the 8x4 (or 4x8) node division will continue to produce 4x4 blocks, therefore, At this time, the 8x4 (or 4x8) nodes cannot continue to be divided.
  • Step 104 Divide the current node by using the current node division mode, without limiting the prediction modes of all coding blocks covered by the current node.
  • the luminance block of the current node is divided by the division method of the luminance block of the current node
  • the chroma block of the current node is divided by the division method of the chroma block of the current node.
  • the prediction mode that does not limit all the coding blocks covered by the current node in step 104 can be understood as: all the coding blocks covered by the current node may not be predicted according to the same prediction mode, that is, the prediction mode of each coding block is parsed, Each coded block is predicted according to the parsed prediction mode.
  • step 103 or step 104 the method further includes:
  • Step 105 Analyze the prediction blocks and residual information of all coding blocks covered by the current node.
  • Step 106 Decode each coded block to obtain a reconstructed signal of the image block corresponding to the current node.
  • the prediction block includes: prediction mode (indicating intra prediction or non-intra prediction mode), intra prediction mode, inter prediction mode, motion information, and the like.
  • the motion information may include prediction direction (forward, backward or bidirectional), reference frame index (reference index), motion vector (motion vector) and other information.
  • Residual information includes: coded block flags (coded, block, flag, cbf), transform coefficients, transform types (eg, DCT-2, DST-7, DCT-8), etc.
  • the transform type can default to DCT-2 transform.
  • the prediction block analysis of the luminance CB divided by the current node includes skip_flag, merge_flag, cu_pred_mode to default to 0, 0, and 1 (ie skip_flag, merge_flag, cu_pred_mode None of them appear in the code stream), or skip_flag and cu_pred_mode default to 0 and 1 respectively (that is, skip_flag and cu_pred_mode do not appear in the code stream).
  • the intra prediction mode information of the brightness CB will be resolved; the chroma obtained by the current node division
  • the prediction block parsing of CB includes parsing the intra prediction mode of chroma CB.
  • the analysis method of the intra prediction mode of the chroma CB may be: 1) obtained by parsing the syntax elements from the code stream; 2) directly set to one of the set of chroma intra prediction modes, such as the linear model mode and the DM mode (chroma derived mode, DM) and IBC mode.
  • the prediction mode analysis of the CU divided by the current node includes resolution of skip_flag or/and merge_flag, cu_pred_mode is set to 0 by default, and inter prediction blocks are resolved, such as fusion index (merge index), inter prediction direction (inter dir), reference frame index (reference index), motion vector predictor index (motion vector predictor index) and motion vector difference component (motion vector difference).
  • skip_flag is a flag of skip mode, a value of 1 indicates that the current CU uses the skip mode, and a value of 0 indicates that the current CU does not use the skip mode.
  • merge_flag is the fusion mode flag.
  • a value of 1 indicates that the current CU uses the fusion mode; a value of 0 indicates that the fusion mode is not used.
  • cu_pred_mode is the coding unit prediction mode flag.
  • a value of 1 indicates that the current prediction unit uses intra prediction; a value of 0 indicates that the current prediction unit uses ordinary inter prediction (identifies the inter prediction direction, reference frame index, motion vector prediction in the code stream Value index, motion vector difference, etc.).
  • the prediction block analysis of the luminance CB divided by the current node includes parsing skip_flag or/and merge_flag, and cu_pred_mode is set to 0 by default, parsing inter prediction Blocks, such as merge index (merge index), inter prediction direction (inter dir), reference frame index (reference index), motion vector predictor index (motion vector predictor index) and motion vector difference (motion vector difference).
  • merge index merge index
  • inter prediction direction inter dir
  • reference frame index reference frame index
  • motion vector predictor index motion vector predictor index
  • motion vector difference motion vector difference
  • the prediction block of the chroma CB obtained by the current node does not need to be analyzed, and the chroma CB is divided into 2x2 chroma sub-blocks (this division method may be a division method S), the motion information of each 2x2 chroma sub-block is the motion information of the 4x4 luminance region corresponding to each 2x2 chroma sub-block.
  • this division method no chroma small block using intra prediction will be generated, nor will a transform block smaller than 16 pixels be generated, so the above intra prediction problem and coefficient coding problem are solved.
  • the prediction block of the chroma CB divided by the current node does not need to be parsed, the chroma prediction block and the chroma coding block have the same size, and the chroma CB
  • the motion information of is the motion information of a preset position in the brightness area corresponding to the chroma CB (such as the center, lower right corner, or upper left corner of the brightness area, etc.).
  • the intra prediction mode in this embodiment is a prediction mode that uses the spatial reference pixels of the image where the coding block is located to generate the prediction value of the coding block, such as direct current mode (DC mode), plane mode (Planar mode) ), angular mode (angular mode), may also include template matching mode (template matching mode), IBC mode.
  • the inter prediction mode is a prediction mode that uses the time-domain reference pixels in the reference image of the coding block to generate the prediction value of the coding block, such as skip mode (Skip mode), fusion mode (Merge mode), AMVP (advanced motion vector prediction) Mode or ordinary Inter mode.
  • the prediction block of each coding block performs inter prediction or intra prediction on each coding block to obtain an inter prediction image or an intra prediction image of each coding block. Then, according to the residual information of each coding block, the transform coefficient is subjected to inverse quantization and inverse transform processing to obtain a residual image, which is superimposed on the predicted image of the corresponding region to generate a reconstructed image.
  • the image block with a preset size includes a brightness block with a first preset size
  • step 102 includes:
  • the brightness block of the first preset size refers to a brightness block with a pixel size of 4 ⁇ 4.
  • step 103 includes: using all the encoding blocks covered by the current node Intra prediction.
  • step 104 includes: dividing the luminance block of the current node In this way, the luminance block of the current node is divided, and the chroma block of the current node is used to divide the chroma block of the current node, without limiting the prediction mode of all coding blocks covered by the current node.
  • the image block with a preset size includes a chroma block with a second preset size
  • step 102 includes:
  • the chroma block of the second preset size refers to a chroma block with a pixel size of 2 ⁇ 2, 2 ⁇ 4, or 4 ⁇ 2.
  • step 103 includes: covering all Use intra prediction for coding blocks, or use inter prediction for all coding blocks covered by the current node.
  • step 104 includes: using the color of the current node
  • the division method of the degree block divides the chrominance block of the current node, and the brightness block of the current node is used to divide the brightness block of the current node, which does not limit the prediction mode of all coding blocks covered by the current node.
  • the image prediction method provided in this embodiment determines whether an image block having a preset size is obtained by dividing the current node based on the current node division method by obtaining the current node division method, where the image block includes a luma block or a chroma block .
  • intra prediction is used for all coding blocks covered by the current node
  • inter coding is used for all coding blocks covered by the current node prediction.
  • the above method uses intra-frame or inter-frame prediction for all coding blocks of the current node, which can realize parallel processing of all coding blocks of the current node, improve the processing performance of image prediction, and thus increase the processing speed of coding and decoding.
  • the image prediction method determines whether the current node is divided based on the division method of the brightness block of the current node to obtain a brightness block with a first preset size Detailed description is made, and the judgment set of the luminance block with the first preset size is specifically disclosed.
  • FIG. 10 is a schematic flowchart of a second image prediction method provided by an embodiment of the present application. As shown in FIG. 10, the image prediction method provided in this embodiment includes:
  • Step 201 Obtain the division mode of the current node.
  • the division information of the current node is analyzed, and if the division information indicates that the brightness block of the current node is divided, the manner of dividing the brightness block of the current node is further determined.
  • the division method of the brightness block includes at least one of quadtree division, vertical bisection, horizontal bisection, vertical trisection, and horizontal trisection. Of course, it may be other division modes, which is not specifically limited in this embodiment. .
  • Step 202 According to the size and division mode of the current node, determine whether dividing the current node based on the division mode will result in a brightness block having a first preset size.
  • the brightness block with the first preset size may be a brightness block with a pixel size of 4 ⁇ 4 or 8 ⁇ 8.
  • step 203 is performed; when it is determined that dividing the current node based on the division mode will not result in brightness having the first preset size In the case of a block, step 204 is performed.
  • the size of the current node and the division method of the brightness block of the current node it is determined whether division of the current node based on the division method of the brightness block will result in a brightness block having a first preset size.
  • the size of the current node may be understood as the pixel size of the image block corresponding to the current node.
  • the size of the current node can be determined according to the width and height of the image block corresponding to the current node, the area of the image block corresponding to the current node, or the number of brightness pixels of the image block corresponding to the current node.
  • the current node includes 128 brightness pixels.
  • the area of the current node can be described as 128, and the product of the width and height of the current node can be described as 128.
  • determining to divide the current node based on the division method of the brightness block will obtain a brightness block of the first preset size, including one or more of the following first set.
  • the current node contains M1 pixels and the current node is divided into quadtrees, for example, M1 is 64;
  • the current node contains M2 pixels and the current node is divided into a trigeminal tree, for example, M2 is 64;
  • the current node contains M3 pixels and the current node is divided into binary trees, for example, M3 is 32;
  • the current node contains 64 luminance pixels and the current node uses a tri-tree division (vertical three-point or horizontal three) or quad-tree division, or the current node contains 32 luminance pixels and uses a binary tree division (vertical two-point or horizontal two-point );
  • the width of the current node is equal to 4 times the second threshold, the height is equal to the second threshold, and the division mode of the current node is vertical trigeminal tree division;
  • the width of the current node is equal to the second threshold, and the height is equal to 4 times the second threshold, and the current node is divided into horizontal tritrees;
  • the width of the current node is equal to 2 times the second threshold, the height is equal to the second threshold, and the division mode of the current node is vertical dichotomy;
  • the height of the current node is equal to 2 times the second threshold, the width is equal to the second threshold and the current node is divided into two levels;
  • the width or/and height of the current node is twice the second threshold and the current node is divided into quadtrees.
  • the width of the current node is the width of the brightness block corresponding to the current node
  • the height of the current node is the height of the brightness block corresponding to the current node.
  • the second threshold may be 4.
  • the above-mentioned first set applies to video data formats of YUV4:2:0 or YUV4:2:2.
  • the brightness block of the first preset size is a pixel size of 4 ⁇ 4
  • determine whether to divide the current node based on the division mode The brightness block with the first preset size will be obtained, which may include:
  • the number of sampling points of the current node's luminance block is 64, and the division method is quadtree division; or,
  • the number of sampling points of the brightness block of the current node is 64, and the division method is a tri-tree division; or,
  • the number of sampling points of the luminance block of the current node is 32, and the division method is binary tree division.
  • the number of sampling points of the brightness block of the current node is the number of brightness pixels (pixel size) of the image block corresponding to the current node.
  • Step 203 Use intra prediction on all coding blocks covered by the current node.
  • step 203 it may be that intra-prediction is only performed on the coding block having the luminance block with the first preset size, without limiting the prediction mode of other coding blocks covered by the current node.
  • Intra prediction is used for all coding blocks covered by the current node, which may include:
  • the luminance block of the current node is divided according to the division method of the luminance block to obtain N luminance coding tree nodes; the chroma block of the current node is not Divide and get a chroma coding block (referred to as chroma CB)
  • the N luminance coding tree nodes can be restricted to not continue to be divided, or do not make this restriction. If the luminance coding tree node continues to be divided, then the division method is analyzed to recursively divide. When the luminance coding tree node is no longer divided, it corresponds to a luminance coding block (abbreviated as luminance CB).
  • luminance CB a luminance coding block
  • the luma CB uses intra prediction to obtain a luma prediction block corresponding to the luma CB.
  • the chroma CB uses intra prediction to obtain a chroma prediction block corresponding to the chroma CB, and the size of the chroma prediction block and the chroma CB are the same.
  • using intra prediction on all coding blocks covered by the current node may include:
  • the luma block included in the current node is used as the luma code block, and intra prediction is used for the luma code block;
  • the chroma block included in the current node is used as the chroma code block, and intra prediction is used for the chroma code block. That is to say, neither the luma block nor the chroma block of the current node may be divided.
  • Step 204 The current node is divided by the current node division mode, and the prediction modes of all coding blocks covered by the current node are not limited.
  • Step 204 in this embodiment is the same as step 104 in the embodiment shown in FIG. 9.
  • Step 204 in this embodiment is the same as step 104 in the embodiment shown in FIG. 9.
  • the method further includes:
  • Step 205 Analyze the prediction blocks and residual information of all coding blocks covered by the current node.
  • Step 206 Decode each coded block to obtain a reconstructed signal of the image block corresponding to the current node.
  • step 205 and step 206 are the same as step 105 and step 106 in the embodiment shown in FIG. 9.
  • step 205 and step 206 are the same as step 105 and step 106 in the embodiment shown in FIG. 9.
  • steps 105 and step 106 are the same as step 105 and step 106 in the embodiment shown in FIG. 9.
  • the image prediction method provided in this embodiment determines whether the first preset size is obtained by dividing the current node based on the division method of the luminance block by obtaining the division method of the current node, and according to the size of the current node and the division method of the luminance block
  • intra prediction is used for all coding blocks covered by the current node.
  • the above method uses intra prediction on all coding blocks of the current node, which can realize parallel processing of all coding blocks of the current node, improve the processing performance of image prediction, and thus increase the processing speed of coding and decoding.
  • step 204 may include:
  • Step 2041 Determine whether dividing the current node based on the dividing mode will result in a chroma block having a second preset size.
  • step 2042 is performed; when it is determined that dividing the current node based on the division mode will not result in a second preset size In the case of chroma blocks, step 2043 is executed.
  • step 2041 includes: according to the size of the current node and the division method of the chroma block, determining whether dividing the current node based on the division method of the chroma block will result in a chroma block having a second preset size.
  • the chroma block of the second preset size may be a chroma block with a pixel size of 2 ⁇ 2, 2 ⁇ 4, or 4 ⁇ 2.
  • determining to divide the current node based on the division method of the chroma block will obtain a chroma block with a second preset size, including one or more of the following second set .
  • the second set includes:
  • the size of the chroma block of at least one child node of the current node is 2x2, 2x4, or 4x2;
  • the width or height of the chroma block of at least one child node of the current node is 2;
  • the current node contains 64 luminance pixels and the division mode of the current node is tri-tree division or quad-tree division;
  • the current node contains 32 luminance pixels and the current node is divided into binary tree division or trigeminal tree division;
  • the area of the current node (or the product of width and height) is S, S/2 ⁇ th1, and the current node is divided into vertical bisection or horizontal bisection; or the area of the current node (or product of width and height) S, S/4 ⁇ th1, and the current node is divided into vertical three-point, horizontal three-point, or quadtree division.
  • the threshold th1 is 32.
  • the second set includes:
  • the size of the chroma block of at least one child node of the current node is 2x2, 2x4, or 4x2;
  • N1 is 64, 128, or 256.
  • N2 is 64 or 256.
  • N3 is 64, 128, or 256.
  • the area of the current node (or the product of width and height) is S, S/2 ⁇ th1, and the division of the current node is vertical bisection or horizontal bisection; or the area of the current node (or the product of width and height) S, S/4 ⁇ th1, and the current node is divided into vertical three-point, horizontal three-point, or quadtree division.
  • the threshold th1 is 64.
  • the brightness block with the first preset size may be a 4 ⁇ 4 brightness block.
  • the chroma of the second preset size The block may be a chroma block with a pixel size of 2 ⁇ 4 or 4 ⁇ 2, excluding a chroma block with a pixel size of 2 ⁇ 2.
  • the brightness block with the first preset size may be a 4 ⁇ 4 brightness block.
  • the chroma of the second preset size The block may be a luminance block with a pixel size of 4 ⁇ 8 or 8 ⁇ 4, excluding a luminance block with a pixel size of 4 ⁇ 4.
  • the chroma block of the second preset size is a chroma block with a pixel size of 2 ⁇ 4, or 4 ⁇ 2, or a luma block with a pixel size of 4 ⁇ 8, or 8 ⁇ 4,
  • Judging whether dividing the current node based on the dividing mode will result in a chroma block of a second preset size may include:
  • the number of sampling points of the brightness block of the current node is 64, and the division method is binary tree division; or,
  • the number of sampling points of the luminance block of the current node is 128, and the division method is tri-tree division.
  • Step 2042 Use intra prediction for all coding blocks covered by the current node, or use inter prediction for all coding blocks covered by the current node.
  • Intra-frame prediction or inter-frame prediction is used for all coding blocks covered by the current node, which can be determined by the following method.
  • Method 1 Analyze the prediction mode status indicator of the current node, and when the value of the prediction mode status indicator is the first value, use inter prediction for all coding blocks covered by the current node; or, the value of the prediction mode status indicator is the second Value, use intra prediction for all code blocks covered by the current node.
  • This method actually determines the prediction mode for all coding blocks covered by the current node according to the flag bits in the syntax table.
  • the prediction mode state identifier cons_pred_mode_flag is parsed from the code stream. Among them, the first value of cons_pred_mode_flag is set to 0, indicating that all coding blocks obtained by dividing or not dividing the current node use inter prediction, and the second value of cons_pred_mode_flag is set to 1, indicating that the current node is divided or not divided Intra-prediction is used for all coding blocks of.
  • cons_pred_mode_flag is set to 1, indicating that all coding blocks obtained by dividing or not dividing the current node use inter prediction
  • the second value of cons_pred_mode_flag is set to 0, indicating that the current node is divided or not All the divided coding blocks use intra prediction.
  • cons_pred_mode_flag can also be expressed using other identifiers (such as mode_cons_flag), which is not limited in this embodiment.
  • cons_pred_mode_flag can be a syntax element that needs to be parsed during the block division process.
  • the syntax element is parsed, the coding unit prediction mode flag cu_pred_mode of the coding unit of the current node coverage area can no longer be parsed, and its value is the default corresponding to the value of cons_pred_mode_flag value.
  • cons_pred_mode_flag is 0, which means that only the inter-frame prediction is used for the coding units covered by the current node of the current node
  • cons_pred_mode_flag is 1, which means that only the intra-frame prediction is used for the coding blocks covered by the current node.
  • the cu_pred_mode value is deduced to 1, without parsing from the code stream Obtained; if the current node is in the intra-image area and IBC mode is not allowed, then cu_pred_mode is deduced to 1 and cu_skip_flag is 0, and there is no need to parse it from the code stream.
  • the cu_pred_mode value is deduced to 0, and there is no need to parse it from the code stream.
  • the IBC prediction can be attributed to the intra prediction mode, because the reference pixels of the IBC prediction come from the reconstructed pixels in the current image. Therefore, in the embodiment of the present application, the intra prediction may include the IBC mode. That is to say, in the embodiment of the present application, the intra prediction may use the IBC mode, or may use the ordinary intra prediction mode intra, or may use the IBC mode+ordinary intra prediction mode intra. Therefore, in summary of the embodiments of the present application, intra prediction can also be understood as non-inter prediction.
  • the slice type where the current node is located is not an Intra type.
  • Method 2 When the prediction mode of any coding block covered by the current node is inter prediction, use inter prediction for all coding blocks covered by the current node; or, the prediction mode of any coding block covered by the current node is frame In intra prediction, intra prediction is used for all coding blocks covered by the current node.
  • This method actually determines the prediction mode for all the coding blocks covered by the current node according to the prediction mode of any coding block in the current node.
  • any coding block is the first coding block in the decoding order among all coding blocks covered by the current node.
  • this embodiment does not limit the prediction mode of the first coding block B0.
  • the prediction mode of parsing B0 is intra prediction, all coding blocks covered by the current node use intra prediction; when the prediction mode of parsing B0 is inter prediction, all coding blocks covered by the current node use inter prediction.
  • Step 2043 The current node is divided by the current node division mode, and the prediction modes of all coding blocks covered by the current node are not limited.
  • step 203 or step 2042 or step 2043 the method further includes:
  • Step 205 Analyze the prediction blocks and residual information of all coding blocks covered by the current node.
  • Step 206 Decode each coded block to obtain a reconstructed signal of the image block corresponding to the current node.
  • step 205 and step 206 are the same as step 105 and step 106 in the embodiment shown in FIG. 9.
  • step 205 and step 206 are the same as step 105 and step 106 in the embodiment shown in FIG. 9.
  • steps 105 and step 106 are the same as step 105 and step 106 in the embodiment shown in FIG. 9.
  • the image prediction method provided in this embodiment determines whether the first preset size is obtained by dividing the current node based on the division method of the luminance block by obtaining the division method of the current node, and according to the size of the current node and the division method of the luminance block Luminance block, when it is determined that the current node will be divided based on the division method of the luminance block to obtain the luminance block of the first preset size, it is further determined whether the current node will be divided based on the division method of the chroma block Set the size of the chroma block, in the case of determining that the current node will be divided based on the chroma block division method to obtain the chroma block of the second preset size, use intra prediction for all coding blocks covered by the current node, Or both use inter prediction.
  • the above method uses intra-frame or inter-frame prediction for all coding blocks of the current node, which can realize parallel processing of all coding blocks of the current node, improve the processing performance of image prediction,
  • the first example applies to the video data format YUV of 4:2:0 or 4:2:2, or only to the video data format YUV of 4:2:0.
  • the image prediction method in this example includes:
  • Step 1 Obtain the current node division method.
  • Step 2 Determine whether the current node area and division method meet at least one of the following condition A:
  • the area of the current node is equal to 32 and the current node is divided into vertical dichotomy or horizontal dichotomy;
  • the area of the current node is equal to 64 and the division mode of the current node is vertical three-point division, horizontal three-point division, or quadtree division.
  • step 3 is performed.
  • Step 3 Restrict all coding blocks covered by the current node to use intra prediction.
  • Step 4 Determine whether the area and division of the current node meet at least one of the following condition B:
  • the area S of the current node satisfies S/2 ⁇ th1 and the division mode of the current node is vertical dichotomy or horizontal dichotomy;
  • the threshold th1 is related to the video data format. For example, when the video data format is YUV 4:2:0, th1 is 64, and when the video data format is YUV 4:2:2, th1 is 32.
  • step 5 is performed.
  • Step 5 Parsing the flag bit cons_pred_mode_flag from the code stream, and determining, according to the value of cons_pred_mode_flag, that the coding units in the coverage area of the current node all use inter prediction or intra prediction.
  • Step 6 The current node is divided using the current node division mode, and the prediction modes of all coding blocks covered by the current node are not limited.
  • step 6 it also includes:
  • Step 7 Analyze the prediction block and residual information of all coding blocks covered by the current node.
  • Step 8 Decode each coded block to obtain the reconstructed signal of the image block corresponding to the current node.
  • the second example applies to the video data format YUV of 4:2:0.
  • the image prediction method in this example includes:
  • Step 1 Obtain the current node division method.
  • Step 2 Determine whether the area and division of the current node meet the condition C:
  • the area of the current node is equal to 64 and the current node is divided using a horizontal three-point, vertical three-point, or quadtree.
  • Step 3 The coding units of the current node coverage area all use intra prediction.
  • cons_pred_mode_flag is set to 1.
  • Step 4. Determine whether the area and division of the current node meet at least one of condition D:
  • the area of the current node is equal to 64 and the current node uses horizontal dichotomy or vertical dichotomy;
  • the area of the current node is equal to 128 and the current node uses a horizontal third or a vertical third.
  • step 5 is performed.
  • Step 5 Parsing the flag bit cons_pred_mode_flag from the code stream, and determining, according to the value of cons_pred_mode_flag, that the coding units in the coverage area of the current node all use inter prediction or intra prediction.
  • step 6 is performed.
  • Step 6 The current node is divided using the current node division mode, and the prediction modes of all coding blocks covered by the current node are not limited.
  • step 6 it also includes:
  • Step 7 Analyze the prediction block and residual information of all coding blocks covered by the current node.
  • Step 8 Decode each coded block to obtain the reconstructed signal of the image block corresponding to the current node.
  • FIG. 12 is a schematic flowchart of a fourth image prediction method provided by an embodiment of the present application. As shown in FIG. 12, the image prediction method provided in this embodiment includes:
  • Step 301 Obtain the division mode of the current node.
  • the division information of the current node is analyzed, and if the division information indicates that the chroma block of the current node is divided, the division method of the chroma block of the current node is further determined.
  • the division method of the chroma block includes at least one of quadtree division, vertical bisection, horizontal bisection, vertical trisection, and horizontal trisection.
  • quadtree division vertical bisection, horizontal bisection, vertical trisection, and horizontal trisection.
  • Step 302 Determine, according to the size and division mode of the current node, whether to divide the current node based on the division mode to obtain a chroma block with a second preset size.
  • step 303 is performed; when it is determined that dividing the current node based on the division mode will not result in a second preset size
  • step 304 is executed.
  • Step 302 in this embodiment is the same as step 2041 in the embodiment shown in FIG. 11.
  • Step 302 in this embodiment is the same as step 2041 in the embodiment shown in FIG. 11.
  • step 302 may include: according to the size and division manner of the current node, determining whether dividing the current node based on the division manner will result in a brightness block having a third preset size.
  • the brightness block with the third preset size may be a 4 ⁇ 4, 4 ⁇ 8, or 8 ⁇ 4 brightness block.
  • judging whether dividing the current node based on the dividing mode will result in a chroma block of a second preset size may include:
  • the number of sampling points of the current node's luminance block is 64, and the division method is quadtree division; or,
  • the number of sampling points of the brightness block of the current node is 64, and the division method is a tri-tree division; or,
  • the number of sampling points of the luminance block of the current node is 32, and the division method is binary tree division; or,
  • the number of sampling points of the luminance block of the current node is 64, and the division method is binary tree division; or,
  • the number of sampling points of the luminance block of the current node is 128, and the division method is tri-tree division.
  • the chroma block of the second preset size may be a chroma block with a pixel size of 2 ⁇ 4 or 4 ⁇ 2, excluding a chroma block with a pixel size of 2 ⁇ 2.
  • the brightness block with the third preset size may be a brightness block with a pixel size of 4 ⁇ 8 or 8 ⁇ 4, excluding a brightness block with a pixel size of 4 ⁇ 4.
  • judging whether dividing the current node based on the dividing mode will result in a chroma block of the second preset size may include:
  • the number of sampling points of the brightness block of the current node is 64, and the division method is binary tree division; or,
  • the number of sampling points of the luminance block of the current node is 128, and the division method is tri-tree division.
  • Step 303 Use intra prediction for all coding blocks covered by the current node, or use inter prediction for all coding blocks covered by the current node.
  • Whether to use intra prediction for all coding blocks covered by the current node, or to use inter prediction for all coding blocks covered by the current node, can be determined by step 2042 of the embodiment shown in FIG. 11. For details, see the above embodiment. Repeat again.
  • Step 304 Divide the current node by using the current node division mode, without limiting the prediction modes of all coding blocks covered by the current node.
  • Step 304 in this embodiment is the same as step 104 in the embodiment shown in FIG. 9.
  • Step 304 in this embodiment is the same as step 104 in the embodiment shown in FIG. 9.
  • step 303 or step 304 the method further includes:
  • Step 305 Analyze the prediction blocks and residual information of all coding blocks covered by the current node.
  • Step 306 Decode each coded block to obtain a reconstructed signal of the image block corresponding to the current node.
  • Step 305 and step 306 in this embodiment are the same as step 105 and step 106 in the embodiment shown in FIG. 9.
  • Step 305 and step 306 in this embodiment are the same as step 105 and step 106 in the embodiment shown in FIG. 9.
  • steps 105 and step 106 in the embodiment shown in FIG. 9. For details, refer to the foregoing embodiment, and details are not described here.
  • the image prediction method provided in this embodiment determines whether to divide the current node based on the division mode by obtaining the division mode of the current node according to the size and division mode of the current node. When it is determined that dividing the current node based on the division method will result in a chroma block of the second preset size, use intra prediction for all coding blocks covered by the current node, or use inter prediction for all coding blocks covered by the current node .
  • the above method uses intra-frame or inter-frame prediction for all coding blocks of the current node, which can realize parallel processing of all coding blocks of the current node, improve the processing performance of image prediction, and thus increase the processing speed of coding and decoding.
  • step 304 may include:
  • Step 3041 It is judged whether dividing the current node based on the dividing mode will result in a luminance block of the first preset size.
  • step 3042 is performed; when it is determined that dividing the current node based on the division mode will result in the first preset-size brightness block In case, go to step 3043.
  • the brightness block of the first preset size refers to a brightness block with a pixel size of 4 ⁇ 4.
  • the specific determination process is the same as the step 202 of the embodiment shown in FIG.
  • Step 3042 Use intra prediction on all coding blocks covered by the current node.
  • Step 3043 The current node is divided using the current node division mode, and the prediction modes of all coding blocks covered by the current node are not limited.
  • step 303 or step 3042 or step 3043 the method further includes:
  • Step 305 Analyze the prediction blocks and residual information of all coding blocks covered by the current node.
  • Step 306 Decode each coded block to obtain a reconstructed signal of the image block corresponding to the current node.
  • Step 305 and step 306 in this embodiment are the same as step 105 and step 106 in the embodiment shown in FIG. 9.
  • Step 305 and step 306 in this embodiment are the same as step 105 and step 106 in the embodiment shown in FIG. 9.
  • steps 105 and step 106 in the embodiment shown in FIG. 9. For details, refer to the foregoing embodiment, and details are not described here.
  • the image prediction method provided in this embodiment determines whether to divide the current node based on the division mode by obtaining the division mode of the current node according to the size and division mode of the current node. If it is determined that dividing the current node based on the division method does not result in a chroma block of the second preset size, it is further determined whether dividing the current node based on the division mode will result in a luminance block of the first preset size. In the case where the current node is divided in a division manner to obtain a luminance block of the first preset size, intra prediction is used for all coding blocks covered by the current node.
  • the above method uses intra-frame or inter-frame prediction for all coding blocks of the current node, which can realize parallel processing of all coding blocks of the current node, improve the processing performance of image prediction, and thus increase the processing speed of coding and decoding.
  • FIG. 14 is a schematic flowchart of a sixth image prediction method provided by an embodiment of the present application.
  • the image prediction method provided by this embodiment is applied to the video encoder 18 shown in FIG. 8. As shown in FIG. 14, the method provided in this embodiment includes:
  • Step 401 Obtain the division mode of the current node.
  • the type of the slice where the current node is located is B or P. It should be understood that, in the case where the slice type where the current node is located is I, intra prediction should be used by default for all coding blocks covered by the current node.
  • the division mode of the current node can be obtained by parsing the code stream or by the obtained parameters.
  • the current division method of the current node is generally judged, and then the rate-distortion optimization (RDO) method is used to determine the optimal division method as the current node division method.
  • RDO rate-distortion optimization
  • Step 402 Determine whether the size and division mode of the current node satisfy one of the first preset conditions.
  • the first preset condition may include:
  • the number of sampling points of the luminance block of the current node is 64, and the division mode of the current node is quadtree division; or,
  • the number of sampling points of the current node's luminance block is 64, and the current node is divided into a trigeminal tree; or,
  • the number of sampling points of the current node's luminance block is 32, and the current node is divided into a binary tree.
  • the number of sampling points of the brightness block of the current node that is, the number of brightness pixels (pixel size) of the image block corresponding to the current node, can be obtained according to the product of the width and height of the current node.
  • the preset condition 1 further includes the following condition 4):
  • the current node is divided according to the division method to obtain a brightness block of a preset size, and the preset size is 4x4 or 8x8.
  • meeting one of the first preset conditions may result in a luma block of a first preset size (4x4 or 8x8), and may obtain a chroma block of a second preset size (2x4 or 4x2).
  • step 403 if the size and division of the current node satisfy one of the first preset conditions, step 403 is performed; otherwise, the size and division of the current node do not satisfy all the conditions in the first preset condition, Then step 404 is executed.
  • Step 403 Use intra prediction on all coding blocks covered by the current node.
  • mode_constraint_flag when it is determined that all coding blocks covered by the current node use intra prediction, it is not necessary to write the value of mode_constraint_flag to the code stream, and the value of mode_constraint_flag can be set to 1, correspondingly, the decoding end can also use the same The method deduces that the value of mode_constraint_flag is 1.
  • Step 404 Determine whether the size and division mode of the current node satisfy one of the second preset conditions.
  • the second preset condition includes:
  • the number of sampling points of the luminance block of the current node is 64, and the current node is divided into a vertical binary tree or a horizontal binary tree. or,
  • the number of sampling points of the luminance block of the current node is 128, and the division mode of the current node is a vertical trigeminal tree or a horizontal trigeminal tree.
  • the preset condition two further includes condition 3)
  • the current node is divided according to the dividing manner to obtain a chroma block of a preset size, and the preset size is 2x4 or 4x2.
  • step 405 if the size and division mode of the current node satisfy one of the second preset conditions, step 405 is performed; and the size and division mode of the current node do not satisfy all the conditions in the second preset condition, then Go to step 406.
  • Step 405 Use intra prediction for all coding blocks covered by the current node, or use inter prediction for all coding blocks covered by the current node.
  • the prediction mode used by all coding blocks of the current node may be determined in the following ways:
  • the encoder or encoder in one implementation, if the image type or slice type of the current node is type I, it is determined that all encoding blocks in the current node are only applicable to intra prediction (non-inter prediction) ).
  • the value of mode_constraint_flag can be set to 1.
  • the rate-distortion optimization (RDO) method or other methods are used to determine the value of mode_constraint_flag.
  • the RDO method is that the encoder calculates the rate distortion cost (RD cost) when all the coding blocks covered by the current node use inter prediction and intra prediction, and compares the value of the rate distortion cost under the two prediction modes, The prediction mode with the lowest rate distortion value is determined as the final prediction mode. If the prediction mode with the smallest rate distortion value is intra prediction, set mode_constraint_flag to 1; if the prediction mode with the smallest rate distortion value is inter prediction, set the value of mode_constraint_flag to 0, and write the value of mode_constraint_flag to the code stream.
  • RD cost rate distortion cost
  • the encoder first calculates the RD cost when all prediction blocks covered by the current node use inter prediction, and then calculates the RD cost when uses intra prediction, if all code blocks covered by the current node use inter prediction If there is no residual error (for example, in skip mode), it is determined that all the coding blocks covered by the current node use inter prediction, and the value of mode_constraint_flag is set to 0, so there is no need to calculate the RD cost during intra prediction.
  • the encoder can also first calculate the RD cost when all prediction blocks covered by the current node use intra prediction, and then calculate the RD cost when inter prediction is used, and determine the prediction mode with the smallest RD cost as the final prediction mode.
  • the pred_mode_flag value defaults to 1. If the current node is in the intra-image area and IBC mode is not allowed, pred_mode_flag defaults to 1 and cu_skip_flag defaults to 0 (indicating that the current block does not use skip mode). If the current node is in the intra-image area (that is, the image type or slice type (slice_type) of the current node is intra type or I type), mode_constraint_flag defaults to 1.
  • the decoding end or decoder may be to parse the prediction mode status flag (mode_constraint_flag) of the current node; in the case where the value of the prediction mode status flag is the first value, for all Perform inter prediction on the coding blocks belonging to the current node; or, in the case where the value of the prediction mode state identifier is the second value, perform intra prediction on all coding blocks belonging to the current node.
  • mode_constraint_flag the prediction mode status flag of the current node
  • Step 406 Divide the current node by using the current node division mode, without limiting the prediction modes of all coding blocks covered by the current node.
  • the method may further include:
  • Step 407 Determine whether to continue dividing the brightness block and the chroma block of the current node according to the prediction mode of the current node.
  • chroma block is used as the chroma coding block
  • intra prediction is used for the chroma coding block. That is to say, if it is determined that all coding blocks in the current node use intra prediction, the luminance block of the current node is divided according to the division method of the luminance block to obtain N luminance coding tree nodes; the chroma block of the current node is not Divide and get a chroma coding block (abbreviated as chroma CB).
  • the N luminance coding tree nodes can be restricted to not continue to be divided, or do not make this restriction. If the luminance coding tree node continues to be divided, then the division method is analyzed to recursively divide. When the luminance coding tree node is no longer divided, it corresponds to a luminance coding block (abbreviated as luminance CB).
  • luminance CB uses intra prediction to obtain a luma prediction block corresponding to the luma CB.
  • the chroma CB uses intra prediction to obtain a chroma prediction block corresponding to the chroma CB, and the size of the chroma prediction block and the chroma CB are the same.
  • the luminance block and the chrominance block included in the current node are divided according to the division method to obtain the divided node, when the coding tree node When it is no longer divided, it corresponds to a coding unit, including a luminance coding unit and a chroma coding unit, and intra prediction is used for the divided luminance coding unit and chroma coding unit.
  • the luminance blocks included in the current node are divided according to the division method to obtain the divided luminance blocks, and the inter frame is used for the divided luminance blocks Prediction; divide the chroma blocks included in the current node according to the division method to obtain the divided chroma blocks, and use inter prediction on the divided chroma blocks. That is to say, if it is determined that all the coding blocks of the current node use inter prediction, the luminance block of the current node is divided according to the division method of the luminance block to obtain N luminance coding tree nodes; The chroma block is divided into ways to obtain M chroma coding tree nodes.
  • N and M are positive integers, and N and M may be the same or different.
  • the division may not be continued, or the restriction is not made.
  • N luma coding tree nodes correspond to N luma CBs of the current node
  • M chroma coding tree nodes correspond to M chroma CBs of the current node.
  • N luma CBs use inter prediction to obtain corresponding luma prediction blocks
  • M chroma CBs use inter prediction to obtain corresponding chroma prediction blocks.
  • the luminance blocks included in the current node are divided according to the division method to obtain the divided luminance blocks, and the inter frame is used for the divided luminance blocks Prediction; divide the chroma blocks included in the current node according to the division method to obtain the divided chroma blocks, and use inter prediction on the divided chroma blocks. That is to say, if it is determined that all the coding blocks of the current node use inter prediction, the luminance block of the current node is divided according to the division method of the luminance block to obtain N luminance coding tree nodes; The chroma block is divided into ways to obtain M chroma coding tree nodes.
  • N and M are positive integers, and N and M may be the same or different.
  • the division may not be continued, or the restriction is not made.
  • N luma coding tree nodes correspond to N luma CBs of the current node
  • M chroma coding tree nodes correspond to M chroma CBs of the current node.
  • N luma CBs use inter prediction to obtain corresponding luma prediction blocks
  • M chroma CBs use inter prediction to obtain corresponding chroma prediction blocks.
  • the division method is 4x4 (that is, both the width and the height are 4), the division method of the child node is not allowed, or the child node cannot be further divided.
  • a node is restricted to use only inter prediction and the number of brightness sampling points of the node is 32 (or the product of the node's width and height is 32), the node is not allowed to use binary tree division (including horizontal binary tree division and vertical binary tree division ). If the node is restricted to only use inter prediction and the node has 64 brightness sampling points (or the product of the node's width and height is 64), the node is not allowed to use trigeminal tree division (including horizontal trigeminal tree and vertical trigeminal tree division) ). This judgment method is applicable to the video data formats of YUV4:2:0 and YUV4:2:2.
  • the 8x4 (or 4x8) node division will continue to produce 4x4 blocks, therefore, 8x4 (or 4x8) nodes cannot use vertical binary tree division (or horizontal binary tree division), or cannot continue division.
  • the number of sampling points of the luminance block of the current node is 128, and the division method is horizontal tri-tree division or vertical tri-tree division
  • the number of sampling points of the luminance block may be 64
  • the number of sampling points For a 64-luminance node if you use a horizontal tritree or a vertical tritree to divide the child nodes, you will get a 4x4 luma block. Therefore, when it is restricted to only use inter prediction, the node with 64 sampling points cannot Use the horizontal trigeminal tree or vertical trigeminal tree to divide, or can't continue to be divided.
  • Step 408 Predict the coding block of the CU obtained by dividing the current node to obtain the prediction value of the coding block.
  • the encoding end uses the rate-distortion optimization (RDO) method or other methods to determine the optimal use of the current encoding block
  • RDO rate-distortion optimization
  • the current coding block uses the corresponding intra prediction mode for prediction to obtain the prediction value of the current block.
  • the encoding end uses the rate distortion optimization method or other methods to determine the optimal inter prediction mode used by the current encoding block.
  • the block is predicted using the corresponding inter prediction mode to obtain the prediction value of the current block.
  • the encoding end assigns the values of the relevant CU-level syntax elements, and writes the values of each syntax element into the code stream according to the CU-level syntax definition criteria. For example, if all encoding blocks in the current node only use intra prediction, the value of pred_mode_flag is set to 1 and the code stream is not written and does not appear in the code stream. If all the coding blocks in the current node only use intra prediction, and it is determined that the IBC mode is not used, the value of cu_skip_flag (or skip_flag) is 0, and the code stream is not written. Stream to the decoder.
  • pred_mode_flag is set to 0, and the code stream is not written and does not appear in the code stream.
  • pred_mode_ibc_flag is set to 0, the code stream is not written and does not appear in the code stream.
  • the decoder or the decoding end if all the coding blocks in the current node only use intra prediction, you can determine the optimal intra prediction mode used by the current coding block by parsing the code stream or by using the obtained parameters.
  • the coding block uses the corresponding intra prediction mode for prediction to obtain the prediction value of the current block.
  • the decoder or the decoding end if all the coding blocks in the current node only use inter prediction, you can determine the optimal inter prediction mode used by the current coding block by parsing the code stream or by using the obtained parameters. The block is predicted using the corresponding inter prediction mode to obtain the prediction value of the current block.
  • Step 409 Acquire the reconstruction signal of the image block in the current node.
  • the encoder or encoding end After obtaining prediction information using intra prediction or inter prediction, the pixel value of the pixel in the current coding block minus the corresponding prediction information (or prediction value) to obtain the residual information, and then use Discrete Cosine Transform (Discrete Cosine Transformation, DCT) and other methods transform the residual information, and then use quantization entropy coding to obtain the code stream.
  • the encoding end transmits the residual information to the decoding end.
  • the prediction signal is added to the reconstructed residual signal, a further filtering operation is required to obtain a reconstructed signal, which is used as a reference signal for subsequent encoding.
  • the coding block uses the skip mode, there is no residual information and no transformation is required, and the predicted value is the final reconstruction value.
  • the decoder or the decoding end after the prediction signal plus the reconstructed residual signal, a further filtering operation is required to obtain the reconstructed signal. Further, the obtained reconstructed signal is used as a reference signal for subsequent encoding. In particular, if the coding block uses the skip mode, there is no residual information and no transformation is required, and the predicted value is the final reconstruction value.
  • the prediction block of each CU performs inter prediction processing or intra prediction processing on each CU to obtain an inter prediction image or an intra prediction image of each CU.
  • the transform coefficient is subjected to inverse quantization and inverse transform processing to obtain a residual image, which is superimposed on the predicted image of the corresponding area to generate a reconstructed image.
  • This embodiment describes the image prediction method from the perspective of the video decoding end.
  • the video decoder determines whether to use intra-frame or inter-frame prediction for all coding blocks of the current node according to the size and division mode of the current node.
  • the parallel processing of all encoding blocks of the node improves the processing performance of image prediction, thereby increasing the processing speed of decoding.
  • the image prediction method provided in this embodiment is applied to the video encoder 18 and/or the video decoder 24 shown in FIG. 8.
  • This embodiment includes:
  • Step 501 Obtain the division mode of the current node.
  • Step 501 in this embodiment is the same as step 101 in the embodiment shown in FIG. 9 and will not be repeated here.
  • Step 502 Derive the value of the variable modeTypeCondition according to the following method
  • the value of modeTypeCondition is the first value, for example, 0.
  • the prediction mode of the current node is to use only intra prediction or inter prediction, that is, it has been restricted to use only inter prediction or intra prediction (non-inter prediction).
  • the chroma sampling structure is a monochromatic sampling structure (Monochrome) or a 4:4:4 structure.
  • chroma_format_idc the value of chroma_format_idc is 0 or 3.
  • the preset condition 1 further includes the following condition 4):
  • the chroma sampling structure is a monochromatic sampling structure (Monochrome) or a 4:4:4 or 4:2:2 structure.
  • chroma_format_idc is 0 or 3 or 2.
  • modeTypeCondition is the second value, such as 1.
  • the product of the width and height of the luminance block of the current node is 64, and the current node is divided into a horizontal trigeminal tree or a vertical trigeminal tree;
  • the product of the width and height of the luminance block of the current node is 32, and the current node is divided into a horizontal binary tree or a vertical binary tree.
  • the product of the width and height of the brightness block of the current node is 64, and the current node is divided into a horizontal binary tree or a vertical binary tree;
  • the product of the width and height of the brightness block of the current node is 128, and the current node is divided into a horizontal trigeminal tree or a vertical trigeminal tree.
  • the width of the two chroma components is half the width of the corresponding luma component, and the height of the chroma component is half the height of the luma component.
  • the height of the two chroma components is the same as the corresponding luminance component, and the width of the chroma component is half of the width of the corresponding luminance component.
  • separate_colour_plane_flag if separate_colour_plane_flag is equal to 0, the width and height of the two chroma components are the same as the brightness height and width, respectively. Otherwise (separate_colour_plane_flag is equal to 1), the three components are coded with monochrome sample images.
  • separate_colour_plane_flag 1 specifies that that three colour components are of the 4:4:4 chroma format coded separately separated.
  • separate_colour_plane_flag equal to to 0 specified specifies that that the colour components are not coded separately.
  • qtbtt_dual_tree_intra_flag 1 specifies that for I slices, each CTU is split into coding units with 64x64 luma samples using an implicit quadtree split and that these coding units are the root of two separate coding_tree syntax structure for luma and chroma.
  • qtbtt_dual_tree_intra_flag 0 specifies separate coding_tree syntax structure is not used for slices. When qtbtt_dual_tree_intra_flag is not present, it is inferred to be equal to 0.
  • Step 503 Determine the prediction mode types of all coding units in the current node according to the value of modeTypeCondition.
  • modeTypeCondition if the value of modeTypeCondition is 1, it is restricted that all coding units in the current node use intra prediction (MODE_INTRA). Otherwise, if the value of modeTypeCondition is 2, the value of the syntax element mode_constraint_flag is parsed from the code stream. If the value of mode_constraint_flag is 0, then all coding units in the current node use inter prediction (MODE_INTER). If the value is 1, the current All coding units in the node use intra prediction (non-inter prediction/MODE_INTRA).
  • the prediction mode types of all coding units in the current node are not limited, and are the same as the prediction mode types of the current node.
  • Step 504 Determine whether the chroma block and the luma block corresponding to the current node continue to be divided to obtain a chroma coding unit and a luma coding unit.
  • chroma block is used as the chroma coding block
  • intra prediction is used for the chroma coding block. That is to say, if it is determined that all coding blocks in the current node use intra prediction, the luminance block of the current node is divided according to the division method of the luminance block to obtain N luminance coding tree nodes; the chroma block of the current node is not Divide and get a chroma coding block (abbreviated as chroma CB).
  • the N luminance coding tree nodes can be restricted to not continue to be divided, or do not make this restriction. If the luminance coding tree node continues to be divided, then the division method is analyzed to recursively divide. When the luminance coding tree node is no longer divided, it corresponds to a luminance coding block (abbreviated as luminance CB).
  • luminance CB uses intra prediction to obtain a luma prediction block corresponding to the luma CB.
  • the chroma CB uses intra prediction to obtain a chroma prediction block corresponding to the chroma CB, and the size of the chroma prediction block and the chroma CB are the same.
  • the luminance block and the chrominance block included in the current node are divided according to the division method to obtain the divided node, when the coding tree node When it is no longer divided, it corresponds to a coding unit, including a luminance coding unit and a chroma coding unit, and intra prediction is used for the divided luminance coding unit and chroma coding unit.
  • the luminance blocks included in the current node are divided according to the division method to obtain the divided luminance blocks, and the inter frame is used for the divided luminance blocks Prediction; divide the chroma blocks included in the current node according to the division method to obtain the divided chroma blocks, and use inter prediction on the divided chroma blocks. That is to say, if it is determined that all the coding blocks of the current node use inter prediction, the luminance block of the current node is divided according to the division method of the luminance block to obtain N luminance coding tree nodes; The chroma block is divided into ways to obtain M chroma coding tree nodes.
  • N and M are positive integers, and N and M may be the same or different.
  • the division may not be continued, or the restriction is not made.
  • N luma coding tree nodes correspond to N luma CBs of the current node
  • M chroma coding tree nodes correspond to M chroma CBs of the current node.
  • N luma CBs use inter prediction to obtain corresponding luma prediction blocks
  • M chroma CBs use inter prediction to obtain corresponding chroma prediction blocks.
  • the luminance blocks included in the current node are divided according to the division method to obtain the divided luminance blocks, and the inter frame is used for the divided luminance blocks Prediction; divide the chroma blocks included in the current node according to the division method to obtain the divided chroma blocks, and use inter prediction on the divided chroma blocks. That is to say, if it is determined that all the coding blocks of the current node use inter prediction, the luminance block of the current node is divided according to the division method of the luminance block to obtain N luminance coding tree nodes; The chroma block is divided into ways to obtain M chroma coding tree nodes.
  • N and M are positive integers, and N and M may be the same or different.
  • the division may not be continued, or the restriction is not made.
  • N luma coding tree nodes correspond to N luma CBs of the current node
  • M chroma coding tree nodes correspond to M chroma CBs of the current node.
  • N luma CBs use inter prediction to obtain corresponding luma prediction blocks
  • M chroma CBs use inter prediction to obtain corresponding chroma prediction blocks.
  • the division method is 4x4 (that is, both the width and the height are 4), the division method of the child node is not allowed, or the child node cannot be further divided.
  • a node is restricted to use only inter prediction and the number of brightness sampling points of the node is 32 (or the product of the node's width and height is 32), the node is not allowed to use binary tree division (including horizontal binary tree division and vertical binary tree division ). If the node is restricted to only use inter prediction and the node has 64 brightness sampling points (or the product of the node's width and height is 64), the node is not allowed to use trigeminal tree division (including horizontal trigeminal tree and vertical trigeminal tree division) ). This judgment method is applicable to the video data formats of YUV4:2:0 and YUV4:2:2.
  • the 8x4 (or 4x8) node division will continue to produce 4x4 blocks, therefore, 8x4 (or 4x8) nodes cannot use vertical binary tree division (or horizontal binary tree division), or cannot continue division.
  • the number of sampling points of the luminance block of the current node is 128, and the division method is horizontal tri-tree division or vertical tri-tree division, the number of sampling points of the luminance block may be 64, and the number of sampling points If the brightness node is 64, if a child node is used to divide the horizontal tri-tree or vertical tri-tree, you will get a 4x4 brightness block. Therefore, when it has been restricted to only use inter prediction, the node with 64 sampling points cannot Use the horizontal trigeminal tree or vertical trigeminal tree to divide, or can't continue to be divided.
  • Step 505 Analyze the coding unit to obtain prediction mode information
  • the syntax elements related to intra or inter prediction are parsed to obtain the final prediction mode of the coding unit. Use the corresponding prediction mode to make predictions to get the predicted value.
  • the cu_pred_mode value is deduced to 1, without parsing from the code stream Obtained; if the current node is in the intra-image area and IBC mode is not allowed, then cu_pred_mode is deduced to 1 and cu_skip_flag is 0, and there is no need to parse it from the code stream.
  • the cu_pred_mode value is deduced to 0, and there is no need to parse it from the code stream.
  • Step 506 Decode each coded block to obtain a reconstructed signal of the image block corresponding to the current node.
  • the prediction block of each CU performs inter prediction processing or intra prediction processing on each CU to obtain an inter prediction image or an intra prediction image of each CU.
  • the transform coefficient is subjected to inverse quantization and inverse transform processing to obtain a residual image, which is superimposed on the predicted image of the corresponding area to generate a reconstructed image.
  • the image prediction method provided by this embodiment is applied to the video encoder 18 shown in FIG. 8.
  • This embodiment includes:
  • Step 601 Obtain the division mode of the current node.
  • Step 601 in this embodiment is the same as step 501, and will not be repeated here.
  • Step 602 Derive the value of the variable modeTypeCondition according to the following method
  • the value of modeTypeCondition is the first value, for example, 0.
  • the prediction mode of the current node is to use only intra prediction or inter prediction, that is, it has been restricted to use only inter prediction or intra prediction (non-inter prediction).
  • the chroma sampling structure is a monochromatic sampling structure (Monochrome) or a 4:4:4 structure.
  • chroma_format_idc the value of chroma_format_idc is 0 or 3.
  • the preset condition 1 further includes the following condition 4):
  • the chroma sampling structure is a monochromatic sampling structure (Monochrome) or a 4:4:4 or 4:2:2 structure.
  • chroma_format_idc is 0 or 3 or 2.
  • modeTypeCondition is the second value, such as 1.
  • the product of the width and height of the luminance block of the current node is 64, and the current node is divided into a horizontal trigeminal tree or a vertical trigeminal tree;
  • the product of the width and height of the luminance block of the current node is 32, and the current node is divided into a horizontal binary tree or a vertical binary tree.
  • the product of the width and height of the brightness block of the current node is 64, and the current node is divided into a horizontal binary tree or a vertical binary tree;
  • the product of the width and height of the brightness block of the current node is 128, and the current node is divided into a horizontal trigeminal tree or a vertical trigeminal tree.
  • Step 603 Determine the prediction mode types of all coding units in the current node according to the value of modeTypeCondition.
  • modeTypeCondition if the value of modeTypeCondition is 1, it is restricted that all coding units in the current node use intra prediction (MODE_INTRA).
  • the optional mode_constraint_flag is set to 1.
  • the value of the syntax element mode_constraint_flag is determined using the RDO method. For example, first calculate the RD cost when all coding units in the current node use inter prediction, and then calculate the RD cost when using intra prediction, where if all coding units in the current node use inter prediction, there is no residual ( (For example, skip mode), it is determined that all coding units in the current node use inter prediction, and the value of mode_constraint_flag is set to 0, so there is no need to calculate the RD cost during intra prediction. It is also possible to first calculate the RD cost when all the coding units in the current node use intra prediction, then calculate the RD cost when using inter prediction, and then obtain the prediction mode with the smallest RD cost to determine the final prediction.
  • the value of modeTypeCondition is 2
  • the value of the syntax element mode_constraint_flag is determined using the RDO method. For example, first calculate the RD cost when all coding units in the current node use inter prediction, and then calculate the RD cost
  • the prediction mode types of all coding units in the current node are not limited, and are the same as the prediction mode types of the current node.
  • the pred_mode_flag value defaults to 1; if the current node In the intra-image area, and IBC mode is not allowed, pred_mode_flag defaults to 1, and cu_skip_flag is 0.
  • Step 604 Determine the division method of the chroma block and the luma block corresponding to the current node, and obtain a chroma coding unit and a luma coding unit.
  • Step 605 Predict the coding block of the CU divided by the current node to obtain the prediction value of the coding block.
  • the coding end uses the Rate-distortion Optimization (RDO) method or other methods to determine the optimal intra prediction mode used by the current coding block.
  • RDO Rate-distortion Optimization
  • the current coding block The corresponding intra prediction mode is used for prediction to obtain the prediction value of the current block.
  • the coding end uses the rate distortion optimization method or other methods to determine the optimal inter prediction mode used by the current coding block, and the current coding block uses the corresponding inter prediction mode. Prediction to get the predicted value of the current block.
  • the encoding end assigns the values of the relevant CU-level syntax elements, and writes the values of each syntax element into the code stream according to the CU-level syntax definition criteria. For example, if all encoding blocks in the current node only use intra prediction, the value of pred_mode_flag is set to 1 and the code stream is not written and does not appear in the code stream. If all the coding blocks in the current node only use intra prediction, and it is determined that the IBC mode is not used, the value of cu_skip_flag (or skip_flag) is 0, and the code stream is not written. Stream to the decoder.
  • pred_mode_flag is set to 0, and the code stream is not written and does not appear in the code stream.
  • pred_mode_ibc_flag is set to 0, the code stream is not written and does not appear in the code stream.
  • Step 606 Obtain the reconstruction signal of the image block in the current node
  • the pixel value of the pixel in the current coding block is subtracted from the corresponding prediction information (or prediction value) to obtain residual information, and then using discrete cosine transform (Discrete Cosine Transformation, DCT ) And other methods to transform the residual information, and then use quantization entropy coding to get the code stream.
  • the encoding end transmits the residual information to the decoding end.
  • the prediction signal is added to the reconstructed residual signal, a further filtering operation is required to obtain a reconstructed signal, which is used as a reference signal for subsequent encoding.
  • the coding block uses the skip mode, there is no residual information and no transformation is required, and the predicted value is the final reconstruction value.
  • the image prediction device 40 provided by this embodiment includes:
  • the obtaining module 41 is used to obtain the division mode of the current node
  • the judging module 42 is used to judge whether dividing the current node based on the dividing method will obtain an image block with a preset size; the image block includes a luma block or a chroma block;
  • the execution module 43 is configured to use intra prediction on all coding blocks covered by the current node when it is determined that the current node will be divided based on the division mode to obtain an image block having the preset size, Or, inter prediction is used for all coding blocks covered by the current node.
  • the image block with a preset size includes a brightness block with a first preset size
  • the judgment module 42 is specifically configured to: determine based on the size of the current node and the division method Whether the current node is obtained by dividing the current node in the division manner described above will result in a brightness block having a first preset size.
  • the execution module 43 is specifically configured to:
  • Intra prediction is used for all coding blocks covered by the current node.
  • the judgment module 42 is further configured to judge the current node based on the division mode Whether the division will result in a chroma block of the second preset size;
  • the execution module 43 is specifically configured to encode all the coverage of the current node
  • the block uses intra prediction, or uses inter prediction for all coding blocks covered by the current node.
  • the image block with a preset size includes a chroma block with a second preset size
  • the judgment module 42 is specifically configured to: based on the size and division mode of the current node, determine Whether the current node is obtained by dividing the current node in the dividing manner will result in a chroma block with a second preset size.
  • the execution module 43 is specifically configured to:
  • inter prediction is used for all coding blocks covered by the current node; or, when the value of the prediction mode state identifier is the second value, the All coding blocks covered by the current node use intra prediction.
  • the execution module 43 is specifically configured to: When the prediction mode of a coding block is inter prediction, inter prediction is used for all coding blocks covered by the current node; or, when the prediction mode of any coding block covered by the current node is intra prediction, All coding blocks covered by the current node use intra prediction.
  • the any coding block is the first coding block in the decoding order among all coding blocks covered by the current node.
  • the execution module 43 is specifically configured to:
  • intra prediction is used for all coding blocks covered by the current node.
  • the execution module 43 is specifically configured to:
  • inter prediction is used for all coding blocks covered by the current node; or, when the value of the prediction mode state identifier is the second value, the All coding blocks covered by the current node use intra prediction.
  • the execution module 43 is specifically configured to: When the prediction mode of the coding block is inter prediction, inter prediction is used for all coding blocks covered by the current node; or, when the prediction mode of any coding block covered by the current node is intra prediction, Intra prediction is used for all coding blocks covered by the current node.
  • execution module 43 is specifically used to:
  • the chroma blocks are divided to obtain the divided chroma blocks, and inter prediction is used for the divided chroma blocks.
  • execution module 43 is specifically used to:
  • the coding block uses inter prediction for the chroma coding block.
  • the obtaining module 41 is further used to obtain the subdivision manner of the child nodes of the current node, the child nodes include Luma and chroma blocks;
  • the judging module 42 is further configured to judge whether dividing the child nodes of the current node based on the sub-division mode will result in a brightness block having a first preset size
  • the execution module 43 is specifically configured to divide the child nodes of the current node The node is divided by a division method other than the sub-division method to obtain the corresponding coding block, and the inter prediction is used for the corresponding coding block, or the sub node of the current node is used as the coding block to use the inter frame prediction.
  • the image prediction apparatus provided by the embodiments of the present application may execute the technical solutions of the foregoing method embodiments, and the implementation principles and technical effects are similar, and are not described herein again.
  • the video encoding device 50 provided in this embodiment includes a processor 51 and a memory 52 for storing executable instructions of the processor 51; wherein the processor 51 may perform the above method embodiment
  • the image prediction method corresponding to the video encoding device has similar implementation principles and technical effects, and will not be repeated here.
  • the memory 52 may be independent or integrated with the processor 51.
  • the video encoding device 50 further includes a bus 53 for connecting the memory 52 and the processor 51.
  • the video decoding device 60 provided by this embodiment includes a processor 61 and a memory 62 for storing executable instructions of the processor 61; wherein the processor 61 may perform the above method embodiment
  • the image prediction method corresponding to the video decoding device has similar implementation principles and technical effects, which will not be repeated here.
  • the memory 62 may be independent or integrated with the processor 61.
  • the video decoding device 60 further includes a bus 63 for connecting the memory 62 and the processor 61.
  • the image prediction system provided by this embodiment includes a video acquisition device 70, a video encoding device 50 of the embodiment shown in FIG. 16, a video decoding device 60 of the embodiment shown in FIG. 17, and a display device 80.
  • the video encoding device 50 is respectively connected to the video acquisition device 70 and the video decoding device 60, and the video decoding device 60 is connected to the display device 80.
  • the video encoding device 50 receives the video or image information sent by the video capturing device 70.
  • the video encoding device 50 may execute the image prediction method corresponding to the video encoding device 50 in the above method embodiment.
  • the video encoding device 50 converts the encoded video or The image information is sent to the video decoding device 60, and the video decoding device 60 can execute the image prediction method corresponding to the video decoding device 60 in the above method embodiment, and the video decoding device 60 sends the decoded video or image information to the display device 80 for display.
  • the image prediction system provided by the embodiments of the present application includes a video encoding device that can perform the above method embodiments and a video decoding device that can perform the above method embodiments.
  • the implementation principles and technical effects are similar, and are not repeated here.
  • Embodiments of the present application also provide a computer-readable storage medium on which a computer program is stored, and the computer program is executed by a processor to implement various steps of the foregoing method embodiments.
  • An embodiment of the present application also provides a video decoding method.
  • the method includes:
  • the current node includes a luma block and a chroma block
  • the chroma block is a chroma block less than or equal to a first preset value or the chroma block A chroma block whose number of pixels in the block is less than or equal to the second preset value;
  • the current node is further divided based on the current node division method, a small chroma block will be obtained, and inter prediction is performed on the coding block obtained by dividing the current node as the root node, or on The current node performs intra prediction on a coding block (coding block) obtained by dividing the root node, thereby obtaining prediction information of the divided coding block.
  • performing inter prediction on a coding block (coding block) obtained by dividing the current node as a root node includes: dividing all coding blocks (coding block) obtained by dividing the current node as a root node ) Perform inter prediction; or,
  • the performing intra prediction on a coding block (coding block) obtained by dividing the current node as a root node includes: performing intra frame on all coding blocks (coding block) obtained by dividing the current node as a root node prediction.
  • the performing inter prediction on the coding block (block) obtained by dividing the current node as the root node includes: executing all the chroma blocks obtained by dividing the current node as the root node Inter prediction; or,
  • the performing intra prediction on a coding block obtained by dividing the current node as a root node includes performing intra prediction on all chroma small blocks obtained by dividing the current node as a root node .
  • the performing inter prediction on the coding block (block) obtained by dividing the current node as the root node includes: coding unit (coding unit) obtained by dividing the current node as the root node Perform inter prediction; or,
  • the performing intra prediction on a coding block (coding block) obtained by dividing the current node as a root node includes: performing intra prediction on a coding unit (coding unit) obtained by dividing the current node as a root node .
  • the inter prediction is performed on a coding block (coding block) obtained by dividing the current node as a root node, or a coding block (coding block) obtained by dividing the current node as a root node
  • intra prediction includes:
  • intra prediction is performed on a coding block (coding block) obtained by dividing the current node as the root node.
  • the inter prediction is performed on a coding block (coding block) obtained by dividing the current node as a root node, or a coding block (coding block) obtained by dividing the current node as a root node
  • intra prediction includes:
  • intra prediction is performed on a coding block (coding block) obtained by dividing the current node as a root node.
  • the first preset value is 2 or 4, or the second preset value is 16, 8, or 32.
  • performing intra prediction on a coding block obtained by dividing the current node as a root node includes:
  • the inter prediction is performed on a coding block (coding block) obtained by dividing the current node as a root node, or a coding block (coding block) obtained by dividing the current node as a root node
  • intra prediction includes:
  • chroma block included in the current node as a chroma coding block to perform inter prediction or intra prediction.
  • the inter prediction or intra prediction using the chroma block included in the current node as a chroma coding block includes:
  • chroma encoding block as a chroma prediction block for intra prediction
  • An embodiment of the present application also provides a video decoding method.
  • the method includes:
  • the current node includes a luma block and a chroma block
  • a brightness block having the preset size will be obtained, and all coding blocks (coding blocks) obtained by dividing the current node as the root node are executed. Intra prediction, thereby obtaining the prediction block of the divided coding block.
  • the method further includes:
  • the small chroma block is a chroma block that is less than or equal to a first preset value or the small chroma block is a chroma block whose number of pixels in the block is less than or equal to a second preset value;
  • the current node is further divided based on the current node division method, a small chroma block will be obtained, and inter prediction is performed on the coding block obtained by dividing the current node as the root node, or on The current node performs intra prediction on a coding block (coding block) obtained by dividing the root node, thereby obtaining a prediction block of the divided coding block.
  • performing inter prediction on a coding block (coding block) obtained by dividing the current node as a root node includes: dividing all coding blocks (coding block) obtained by dividing the current node as a root node ) Perform inter prediction; or,
  • the performing intra prediction on a coding block (coding block) obtained by dividing the current node as a root node includes: performing intra frame on all coding blocks (coding block) obtained by dividing the current node as a root node prediction.
  • the performing inter prediction on the coding block (coding) block obtained by dividing the current node as a root node includes: executing all small chroma blocks obtained by dividing the current node as a root node Inter prediction; or,
  • the performing intra prediction on a coding block obtained by dividing the current node as a root node includes performing intra prediction on all chroma small blocks obtained by dividing the current node as a root node .
  • the performing inter prediction on the coding block (block) obtained by dividing the current node as the root node includes: coding unit (coding unit) obtained by dividing the current node as the root node Perform inter prediction; or,
  • the performing intra prediction on a coding block (coding block) obtained by dividing the current node as a root node includes: performing intra prediction on a coding unit (coding unit) obtained by dividing the current node as a root node .
  • the inter prediction is performed on a coding block (coding block) obtained by dividing the current node as a root node, or a coding block (coding block) obtained by dividing the current node as a root node
  • intra prediction includes:
  • intra prediction is performed on a coding block (coding block) obtained by dividing the current node as the root node.
  • the inter prediction is performed on a coding block (coding block) obtained by dividing the current node as a root node, or a coding block (coding block) obtained by dividing the current node as a root node
  • intra prediction includes:
  • intra prediction is performed on a coding block (coding block) obtained by dividing the current node as a root node.
  • the first preset value is 2 or 4, or the second preset value is 16, 8, or 32.
  • performing intra prediction on a coding block obtained by dividing the current node as a root node includes:
  • the inter prediction is performed on a coding block (coding block) obtained by dividing the current node as a root node, or a coding block (coding block) obtained by dividing the current node as a root node
  • intra prediction includes:
  • chroma block included in the current node as a chroma coding block to perform inter prediction or intra prediction.
  • the inter prediction or intra prediction using the chroma block included in the current node as a chroma coding block includes:
  • chroma encoding block as a chroma prediction block for intra prediction
  • the performing inter prediction on a coding block (block) obtained by dividing the current node as a root node includes:
  • the sub-nodes of the current node are further divided based on the sub-divided manner, a brightness block with a preset size will be obtained, and the sub-nodes of the current node are divided by a division method other than the sub-divided manner, To obtain a corresponding coding unit and perform inter prediction on the corresponding coding unit, or perform inter prediction using a child node of the current node as a coding unit.
  • the preset size includes 4 ⁇ 4, 4 ⁇ 8, 8 ⁇ 4, 2 ⁇ 4, or 4 ⁇ 2.
  • An embodiment of the present application also provides a video decoding method.
  • the method includes:
  • the current node includes a luma block and a chroma block
  • the current node is divided according to the current node division method To obtain the child nodes of the current node;
  • the sub-nodes of the current node are further divided based on the sub-divided manner, a brightness block with a preset size will be obtained, and the sub-nodes of the current node are divided by a division method other than the sub-divided manner, To obtain a corresponding coding unit and perform inter prediction on the corresponding coding unit, or perform inter prediction using a child node of the current node as a coding unit.
  • the first video decoding method provided by an embodiment of the present application relates to a block division method in video decoding.
  • the video data format in this embodiment is YUV4:2:0 format.
  • a similar method can be used for YUV4:2:2 data.
  • Step 1 Analyze the division mode S of node A. If node A continues to divide, proceed to step 2; if the current node is no longer divided into child nodes, the current node corresponds to a coding unit, and the coding unit information is resolved;
  • the division mode of the node A may be at least one of quadtree division, vertical bisection, horizontal bisection, vertical trisection, and horizontal trisection, or other division modes, which are not limited in this application.
  • the information about the division mode of the current node can be transmitted in the code stream, and the division mode of the current node can be obtained by parsing the corresponding syntax element in the code stream.
  • the current node division method can also be determined based on preset rules, which is not limited in this application.
  • Step 2 Determine whether the chroma block of at least one child node B is a small block among the child nodes obtained by the node A according to the division method S (determine the width, height, and/or division method of the node A, and/or Or whether the width and height of node B satisfy at least one of the conditions). If the chroma block of at least one child node B among the child nodes divided by node A is a small block, perform steps 3 to 6
  • one of the following methods may be used to determine whether the chroma block of at least one child node B of the node A is a small block.
  • the chroma block of at least one child node B of node A is 2x2, 2x4, or 4x2, the chroma block of at least one child node B of node A is a small block.
  • the chroma block of at least one child node B of node A is 2 If the width or height of the chroma block of at least one child node B of node A is 2, the chroma block of at least one child node B of node A is a small block.
  • node A contains 128 luminance pixels and node A uses a tri-tree division, or if node A contains 64 luminance pixels and node A uses a binary-tree division or quad-tree division or tri-tree division, then at least one child of node A
  • the chroma block of node B is a small block.
  • node A contains 256 luminance pixels and the node uses a tri-tree or quad-tree division, or if node A contains 128 luminance pixels and the node uses a binary-tree division, then at least one of the child node B’s chroma blocks For small pieces.
  • N1 is 64, 128, or 256.
  • N2 is 64 or 256.
  • N3 is 64, 128, or 256.
  • node A contains 128 luminance pixels, which can also be described as the area of the current node is 128, or the product of the width and height of node A is 128, which will not be repeated here.
  • Step 3 Restrict all coding units in the coverage area of node A to use intra prediction or all inter prediction.
  • the intra-frame or inter-frame prediction is used, which can realize the parallel processing of small blocks by the hardware and improve the performance of codec.
  • Whether all coding units in the coverage area of the node A use intra prediction or all inter prediction can be determined by one of the following methods.
  • Method 1 Determine according to the flag bit in the grammar table.
  • cons_pred_mode_flag can be a syntax element that needs to be parsed during the block division process. When the syntax element is parsed, the cu_pred_mode of the coding unit of the coverage area of the node A can no longer be parsed, and its value is the default value corresponding to the value of cons_pred_mode_flag.
  • node A can only use the intra prediction mode, for example, node A is in the intra image (that is, the image type of node A is Intra or I), or node A is in the intra image Medium and the sequence does not use IBC technology, then cons_pred_mode_flag defaults to 1, and does not appear in the code stream.
  • the IBC technology can belong to inter prediction or intra prediction.
  • Method 2 Determined by the prediction mode of the first node in the node A area.
  • the prediction mode of the first coding unit B0 is not limited
  • the prediction mode of B0 is intra prediction, all coding units in the coverage area of node A use the frame Intra prediction; if the prediction mode of B0 is inter prediction, then all coding units in the area covered by node A use inter prediction.
  • Step 4 According to the prediction mode used by the coding unit of the coverage area of the node A, determine the division method of the chroma block and the luma block of the node A.
  • the brightness block of node A is divided according to the division mode S described, to obtain N brightness coding tree nodes; the chroma block of node A is not divided, Corresponding to a chroma coding block (abbreviated as chroma CB).
  • the N luminance coding tree nodes can be restricted to not continue to be divided, or do not make this restriction.
  • the division method is analyzed to recursively divide. When the brightness coding tree node is no longer divided, it corresponds to a brightness coding block (abbreviated as brightness CB).
  • the chroma transform block corresponding to the chroma CB is the same size as the chroma coding block, and the chroma prediction block and the chroma coding block are the same size.
  • the luma block and the chroma block of node A are further divided into N coding tree nodes including the luma block and the chroma block according to the division mode S.
  • the coding tree node may continue to be divided or not divided, and when not divided, it corresponds to a coding unit including a luma block and a chroma block.
  • Step 5 Analyze the prediction information and residual information of the CU divided by the node A.
  • the prediction information includes: prediction mode (indicating intra prediction or non-intra prediction mode), intra prediction mode, inter prediction mode, motion information, and the like.
  • the motion information may include prediction direction (forward, backward or bidirectional), reference frame index (reference index), motion vector (motion vector) and other information.
  • the residual information includes: coded block flags (coded block flags, cbf), transform coefficients, transform types (such as DCT-2, DST-7, DCT-8), and so on.
  • coded block flags coded block flags, cbf
  • transform coefficients transform types (such as DCT-2, DST-7, DCT-8), and so on.
  • the transform type can default to DCT-2 transform.
  • the prediction information analysis of the luminance CB divided by Node A includes skip_flag, merge_flag, cu_pred_mode default to 0, 0, and 1 (ie skip_flag, merge_flag, cu_pred_mode None of them appear in the code stream), or skip_flag and cu_pred_mode default to 0 and 1 respectively (that is, skip_flag and cu_pred_mode do not appear in the code stream).
  • the intra prediction mode information of the brightness CB will be resolved; the chroma obtained by the node A division
  • the analysis of the prediction information of the CB includes analyzing the intra prediction mode of the chroma CB.
  • the analysis method of the intra prediction mode of the chroma CB may be: 1) obtained by parsing the syntax elements from the code stream; 2) directly set to one of the set of chroma intra prediction modes, such as the linear model mode and the DM mode (chroma derived mode, DM) and IBC mode.
  • the analysis of the prediction mode of the CU divided by Node A includes parsing skip_flag or/and merge_flag, and cu_pred_mode is set to 0 by default, parsing inter prediction information, such as fusion index (merge index), inter prediction direction (inter dir), reference frame index (reference index), motion vector prediction value index (motion vector predictor index) and motion vector difference component (motion vector difference)
  • inter prediction information such as fusion index (merge index), inter prediction direction (inter dir), reference frame index (reference index), motion vector prediction value index (motion vector predictor index) and motion vector difference component (motion vector difference)
  • skip_flag is a flag of skip mode
  • a value of 1 indicates that the current CU uses the skip mode
  • a value of 0 indicates that the current CU does not use the skip mode
  • merge_flag is the fusion mode flag.
  • a value of 1 indicates that the current CU uses the fusion mode; a value of 0 indicates that the fusion mode is not used.
  • cu_pred_mode is the coding unit prediction mode flag.
  • a value of 1 indicates that the current prediction unit uses intra prediction; a value of 0 indicates that the current prediction unit uses ordinary inter prediction (identifies the inter prediction direction, reference frame index, motion vector prediction in the code stream Value index, motion vector difference, etc.).
  • the intra prediction mode in this embodiment is a prediction mode that uses the spatial reference pixels of the image where the coding block is located to generate the prediction value of the coding block, such as direct current mode (DC mode), planar mode ( Planar mode, angular mode, may also include template matching mode (template matching mode), IBC mode.
  • DC mode direct current mode
  • Planar mode Planar mode, angular mode
  • template matching mode template matching mode
  • IBC mode IBC mode
  • the inter prediction mode is a prediction mode that uses the time-domain reference pixels in the reference image of the coding block to generate the prediction value of the coding block, such as skip mode (Skip mode), fusion mode (Merge mode), and AMVP (advanced motion vector) prediction) mode or ordinary Inter mode, IBC mode, etc.
  • skip mode Skip mode
  • fusion mode Merge mode
  • AMVP advanced motion vector
  • Step 6 Decode each CU to obtain the reconstruction signal of the image block corresponding to node A
  • inter prediction processing or intra prediction processing is performed on each CU from the prediction information of each CU to obtain an inter prediction image or an intra prediction image of each CU.
  • the transform coefficient is subjected to inverse quantization and inverse transform processing to obtain a residual image, which is superimposed on the predicted image of the corresponding area to generate a reconstructed image.
  • the chroma small block using intra prediction will not be generated, thereby solving the problem of intra prediction of small blocks.
  • steps 1, 2, 3, and 6 are the same as the first decoding method. The difference is that:
  • Step 4 Decide how to divide the chroma block and luma block of node A.
  • the brightness block of node A is further divided according to the division mode S, and N brightness coding tree nodes are generated.
  • the chroma block of node A is no longer divided, and corresponds to a chroma coding block (chroma CB).
  • the chroma transform block corresponding to the chroma CB is the same size as the chroma coding block.
  • Step 5 Analyze the prediction information and residual information of the CU divided by the node A.
  • each CU divided by the node A restricts that only intra prediction can be used, the processing is the same as in the first embodiment.
  • the prediction information analysis of the luminance CB divided by node A includes parsing skip_flag or/and merge_flag, and cu_pred_mode is set to 0 by default, parsing inter prediction information, such as fusion Index (merge index), inter prediction direction (inter dir), reference frame index (reference index), motion vector predictor index (motion vector predictor index) and motion vector difference (motion vector difference).
  • inter prediction information such as fusion Index (merge index), inter prediction direction (inter dir), reference frame index (reference index), motion vector predictor index (motion vector predictor index) and motion vector difference (motion vector difference).
  • each CU divided by node A can only use inter prediction, the prediction information of chroma CB divided by node A does not need to be analyzed, and the chroma CB is divided into 2x2 chroma sub-blocks (this division can be divided S), the motion information of each 2x2 chroma sub-block is the motion information of the 4x4 luminance region corresponding to each 2x2 chroma sub-block.
  • Step 1, Step 2, Step 3, Step 4, and Step 6 are the same as the second decoding method. The difference is that:
  • Step 5 Analyze the prediction information and residual information of the CU divided by the node A.
  • each CU divided by the node A restricts that only inter prediction can be used, the analysis of the prediction information of the luminance CB divided by the node A is the same as the second embodiment.
  • the prediction information of chroma CB divided by node A does not need to be analyzed, the size of the chroma prediction block and the chroma coding block are the same, and the motion information of chroma CB is Motion information at a preset position in the brightness area corresponding to the chroma CB (such as the center, lower right corner, or upper left corner of the brightness area, etc.).
  • no chroma small block using intra prediction, a small block transform block, or a chroma small block using inter prediction will be generated.
  • Step 1 Same as Step 1 of the first video decoding method above
  • Step 2 Determine whether there are at least one sub-node B whose brightness block is 4x4 in the sub-nodes obtained by the node A according to the division method S (determine the width, height, and/or division mode of the node A, and /Or whether the width and height of the node B satisfy at least one of the conditions in the first case).
  • a method for determining whether the chroma block of at least one child node B of the node A is a small block is divided into the following two cases.
  • the node A is divided according to the division mode S to obtain a 4x4 brightness block:
  • Node A contains M1 pixels and node A is divided into quadtrees, for example, M1 is 64;
  • Node A contains M2 pixels and node A is divided into a trigeminal tree, for example, M2 is 64;
  • Node A contains M3 pixels and node A is divided into binary trees, for example, M3 is 32;
  • the width of node A is equal to 4 times the second threshold, the height is equal to the second threshold, and the division mode of node A is vertical trigeminal tree division;
  • node A is equal to the second threshold, and the height is equal to 4 times the second threshold, and the division of node A is a horizontal trigeminal tree division;
  • the height of node A is equal to twice the second threshold, the width is equal to the second threshold, and the current node is divided into two levels;
  • the size may be the width and height of the image area corresponding to node A, or the number of luminance pixels included in the image area corresponding to node A, or the area of the image area corresponding to node A.
  • the width of the current node is the width of the current node corresponding to the brightness block
  • the height of the current node is the height of the current node corresponding to the brightness block.
  • the second threshold may be 4.
  • node A contains 128 luminance pixels and node A uses a tri-tree division, or if node A contains 64 luminance pixels and node A uses a binary-tree division or quad-tree division or tri-tree division;
  • node A contains 256 brightness pixels and the node uses a tri-tree or quad-tree division, or if node A contains 128 brightness pixels and the node uses a binary-tree division;
  • N1 is 64, 128, or 256.
  • N2 is 64 or 256.
  • N3 is 64, 128, or 256.
  • node A contains 128 luminance pixels, which can also be described as the area of the current node is 128, or the product of the width and height of node A is 128, which will not be repeated here.
  • Step 3 Same as Step 3 of the first video decoding method above.
  • Step 4 According to the prediction mode used by the coding unit of the coverage area of the node A, determine the division method of the chroma block and the luma block of the node A.
  • the luma block and the chroma block of the node A are divided according to the division mode S to obtain the node A or/and the child nodes in the area covered by the node A.
  • the division mode of the child nodes in the area covered by the node A or/and the node A generates a 4 ⁇ 4 brightness block, the division mode of the child node is not allowed or the child node cannot continue to be divided.
  • node A For example, if the size of node A is 8x8 and the horizontal binary tree (or vertical binary tree) division is used to generate two 8x4 (or two 4x8) nodes, the 8x4 (or 4x8) node division will continue to produce 4x4 blocks, therefore, At this time, the 8x4 (or 4x8) nodes cannot continue to be divided.
  • the implementation method may use the first, second, and third video decoding methods described above, which will not be repeated here. For example, the brightness block of node A is divided, and the chroma block is not divided.
  • Step 5 Analyze the prediction block and residual information of the CU divided by node A.
  • step 5 of the first video decoding method described above It is the same as step 5 of the first video decoding method described above, and will not be repeated here.
  • Step 6 Decode each CU to obtain the reconstruction signal of the image block corresponding to node A
  • Step 1 Same as Step 1 of the first video decoding method above.
  • Step 2 Determine whether there are at least one sub-node B whose brightness block is 4x4 in the sub-nodes obtained by the node A according to the division method S (determine the width, height, and/or division mode of the node A, and /Or whether the width and height of the node B satisfy at least one of the conditions in the first case). If the size (width, height) of node A, and/or the division mode S satisfy at least one of the conditions in case 1, then all intra-coding units in the coverage area of node A are restricted to use intra prediction.
  • Step 3 determine whether the chroma block of at least one child node B is a small block among the child nodes obtained by the node A according to the division method S (determine the size of the node A, and/or the division method S, and/or the node If the width and height of B meet at least one of the conditions in Case 2, perform Step 3 to Step 6.
  • a method for determining whether the chroma block of at least one child node B of the node A is a small block is divided into the following two cases.
  • the node A is divided according to the division mode S to obtain a 4x4 brightness block:
  • Node A contains M1 pixels and node A is divided into quadtrees, for example, M1 is 64;
  • Node A contains M2 pixels and node A is divided into a trigeminal tree, for example, M2 is 64;
  • Node A contains M3 pixels and node A is divided into binary trees, for example, M3 is 32;
  • the width of node A is equal to 4 times the second threshold, the height is equal to the second threshold, and the division mode of node A is vertical trigeminal tree division;
  • node A is equal to the second threshold, and the height is equal to 4 times the second threshold, and the division of node A is a horizontal trigeminal tree division;
  • the height of node A is equal to twice the second threshold, the width is equal to the second threshold, and the current node is divided into two levels;
  • the size may be the width and height of the image area corresponding to node A, or the number of luminance pixels included in the image area corresponding to node A, or the area of the image area corresponding to node A.
  • the width of the current node is the width of the current node corresponding to the brightness block
  • the height of the current node is the height of the current node corresponding to the brightness block.
  • the second threshold may be 4.
  • node A contains 128 luminance pixels and node A uses a tri-tree division, or if node A contains 64 luminance pixels and node A uses a binary-tree division or quad-tree division or tri-tree division;
  • node A contains 256 brightness pixels and the node uses a tri-tree or quad-tree division, or if node A contains 128 brightness pixels and the node uses a binary-tree division;
  • N1 is 64, 128, or 256.
  • N2 is 64 or 256.
  • N3 is 64, 128, or 256.
  • node A contains 128 luminance pixels, which can also be described as the area of the current node is 128, or the product of the width and height of node A is 128, which will not be repeated here.
  • Step 3 Same as Step 3 of the first video decoding method above.
  • Step 4 According to the prediction mode used by the coding unit of the coverage area of the node A, determine the division method of the chroma block and the luma block of the node A.
  • the luma block and the chroma block of the node A are divided according to the division mode S to obtain the node A or/and the child nodes in the area covered by the node A.
  • the division mode of the child nodes in the area covered by the node A or/and the node A generates a 4 ⁇ 4 brightness block, the division mode of the child node is not allowed or the child node cannot continue to be divided.
  • node A For example, if the size of node A is 8x8 and the horizontal binary tree (or vertical binary tree) division is used to generate two 8x4 (or two 4x8) nodes, the 8x4 (or 4x8) node division will continue to produce 4x4 blocks, therefore, At this time, the 8x4 (or 4x8) nodes cannot continue to be divided.
  • the implementation method may use the first, second, and third video decoding methods described above, which will not be repeated here. For example, the brightness block of node A is divided, and the chroma block is not divided.
  • Step 5 Analyze the prediction block and residual information of the CU divided by node A.
  • step 5 of the first video decoding method described above It is the same as step 5 of the first video decoding method described above, and will not be repeated here.
  • Step 6 Decode each CU to obtain the reconstruction signal of the image block corresponding to node A
  • the current region if the current region is divided once to generate 4x4 luminance blocks (for example, 64 luminance pixels use QT division, or 128 luminance pixels use TT division), then the current region defaults to restricting the use of Intra mode.
  • 4x4 luminance blocks for example, 64 luminance pixels use QT division, or 128 luminance pixels use TT division
  • the brightness and chroma are divided together, where if the node division in the current area produces a 4x4 brightness block, this division is not allowed. For example, if the current node is 8x8 and HBT (or VBT) is used to generate two 8x4 nodes, these nodes will continue to be divided to produce 4x4CU, so these 8x4 nodes cannot continue to be divided.
  • the area limitation can only use the Intra mode, it is the same as the implementation in the first embodiment (that is, the brightness is divided, and the chroma is not divided).
  • An embodiment of the present application proposes a block division method to avoid the use of intra prediction mode for chroma blocks with a small area, which is convenient for hardware pipeline processing and decoder implementation.
  • intra prediction mode for chroma blocks with a small area
  • inter prediction you can skip some The parsing process of the syntax elements of the prediction mode, thereby reducing the coding complexity.
  • the block division method can be as follows:
  • all the coding units in the coverage area of the node A are restricted to the intra prediction mode or the inter prediction mode.
  • the luma block of node A continues to be divided according to the division mode S, and the chroma block of node A is no longer divided. If all coding units in the coverage area of node A use inter prediction, the luma block and the chroma block of node A are further divided into N coding tree nodes including the luma block and the chroma block according to the division mode S.
  • the brightness block of node A continues to be divided according to the division mode S, and the chroma block of node A is no longer divided.
  • the chroma transformation block and the chroma coding block are the same size.
  • the chroma prediction block and the chroma coding block are the same size; when all coding units in the coverage area of node A use inter prediction, the chroma prediction block is divided into Sub-blocks (sub-blocks are smaller than chroma-coded blocks), and the motion vector of each sub-block is the motion vector in the luminance region corresponding to the sub-block.
  • the brightness block of node A continues to be divided according to the division mode S; the chroma block of node A is no longer divided.
  • the chroma transform block corresponding to the chroma encoding block is the same size as the chroma encoding block
  • the chroma prediction block is the same size as the chroma encoding block
  • the motion information of the chroma CB is a preset position in the luminance area corresponding to the chroma CB Sports information.
  • Computer readable media may include computer readable storage media, which corresponds to tangible media, such as data storage media, or communication media including any medium that facilitates transfer of a computer program from one place to another (eg, according to a communication protocol).
  • computer-readable media may generally correspond to (1) non-transitory tangible computer-readable storage media, or (2) communication media, such as signals or carrier waves.
  • Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and/or data structures for implementation of the techniques described in this application.
  • the computer program product may include a computer-readable medium.
  • Such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage devices, magnetic disk storage devices or other magnetic storage devices, flash memory, or may be used to store instructions or data structures
  • the desired program code in the form of and any other medium that can be accessed by the computer. And, any connection is properly called a computer-readable medium.
  • coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technology such as infrared, radio, and microwave are used to transmit instructions from a website, server, or other remote source
  • coaxial cable Wire, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of media.
  • the computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other temporary media, but are actually directed to non-transitory tangible storage media.
  • magnetic disks and optical discs include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), and Blu-ray discs, where magnetic discs usually reproduce data magnetically, while optical discs reproduce optically using lasers data. Combinations of the above should also be included within the scope of computer-readable media.
  • DSPs digital signal processors
  • ASICs application specific integrated circuits
  • FPGAs field programmable logic arrays
  • processors may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein.
  • the functions described in the various illustrative logical blocks, modules, and steps described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or in combination Into the combined codec.
  • the techniques can be fully implemented in one or more circuits or logic elements.
  • the technology of the present application may be implemented in a variety of devices or equipment, including wireless handsets, integrated circuits (ICs), or a set of ICs (eg, chipsets).
  • ICs integrated circuits
  • a set of ICs eg, chipsets
  • Various components, modules or units are described in this application to emphasize the functional aspects of the device for performing the disclosed technology, but do not necessarily need to be implemented by different hardware units.
  • various units may be combined in a codec hardware unit in combination with suitable software and/or firmware, or by interoperating hardware units (including one or more processors as described above) provide.

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Abstract

一种图像预测方法、装置、设备、系统及存储介质。该方法包括：获取当前节点的划分方式（401），所述当前节点为当前图像中的编码树单元(coding tree unit)中的图像块；根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足第一条件（402）；在确定所述当前节点满足所述第一条件的情况下，对所有属于当前节点的编码块使用进行帧内预测，从而得到所有属于所述当前节点的编码块的预测值（403）。上述方法对当前节点的所有编码块均使用帧内预测，可以实现对当前节点的所有编码块的并行处理，提高图像预测的处理性能，从而提升编解码的处理速度。

Description

图像预测方法、装置、设备、系统及存储介质
本申请要求于2019年1月8日提交中国国家知识产权局专利局、申请号为201910016466.3、申请名称为“视频解码方法及视频解码器”，2019年3月7日提交中国专利局、申请号为201910173454.1、申请名称为“视频编码器、视频解码器及相应方法”，2019年3月21日提交中国专利局、申请号为201910219440.9、申请名称为“视频编码器、视频解码器及相应方法”，2019年7月30日提交中国专利局、申请号为201910696741.0、申请名称为“图像预测方法、装置、设备、系统及存储介质”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请实施例涉及视频编解码技术领域，尤其涉及一种图像预测方法、装置、设备、系统及存储介质。
背景技术
数字视频能力可并入到多种多样的装置中，包含数字电视、数字直播系统、无线广播系统、个人数字助理(PDA)、膝上型或桌上型计算机、平板计算机、电子图书阅读器、数码相机、数字记录装置、数字媒体播放器、视频游戏装置、视频游戏控制台、蜂窝式或卫星无线电电话(所谓的“智能电话”)、视频电话会议装置、视频流式传输装置及其类似者。数字视频装置实施视频压缩技术，例如，在由MPEG-2、MPEG-4、ITU-T H.263、ITU-T H.264/MPEG-4第10部分高级视频编码(AVC)定义的标准、视频编码标准H.265/高效视频编码(HEVC)标准以及此类标准的扩展中所描述的视频压缩技术。视频装置可通过实施此类视频压缩技术来更有效率地发射、接收、编码、解码和/或存储数字视频信息。
随着信息技术的发展，高清晰度电视，网络会议，IPTV，3D电视等视频业务迅速发展，视频信号以其直观性和高效性等优势成为人们日常生活中获取信息最主要的方式。由于视频信号包含的数据量大，需要占用大量的传输带宽和存储空间。为了有效的传输和存储视频信号，需要对视频信号进行压缩编码，视频压缩技术越来越成为视频应用领域不可或缺的关键技术。
对于编码过程主要包括帧内预测(Intra Prediction)、帧间预测(Inter Prediction)、变换(Transform)、量化(Quantization)、熵编码(Entropy encode)、环内滤波(in-loop filtering)(主要为去块滤波，de-blocking filtering)等环节。将图像划分为编码块之后进行帧内预测或者帧间预测，并且在得到残差之后进行变换量化，最终进行熵编码并输出码流。此处编码块为由像素点组成的大小的阵列(M×N，M可以等于N，也可以不等于N)，并且已知各个像素点位置的像素值。视频解码则相当于视频编码的逆过程。例如，首先利用熵解码反量化反变换得到残差信息，根据解码码流确定当前 块使用的是帧内预测还是帧间预测。如果是帧内编码，则利用当前图像内周围已重建区域内像素点的像素值按照所使用的帧内预测方法构建预测块。如果是帧间编码，则需要解析出运动信息，并使用所解析出的运动信息在已重建的图像中确定参考块，并将参考块内像素点的像素值作为预测块(此过程称为运动补偿(motion compensation，MC))，使用预测块加上残差信息经过滤波操作便可以得到重建信息。
目前，一个8xM(或Mx8)大小的节点使用竖直二分(或水平二分)划分后会产生两个4xM(或Mx4)大小的子节点。类似的，一个16xM(或Mx16)大小的节点使用竖直三分(或水平三分)划分后会产生两个4xM(或Mx4)大小的子节点和一个8xM(或Nx8)大小的子节点。对于YUV4:2:0的数据格式，色度分量的分辨率为亮度分量的1/2，即一个4xM的节点包含了一个4xM的亮度块和两个2x(M/2)的色度块。因此，对当前节点按照预设划分方式进行划分可能会产生2x2、2x4、4x2等色度小块。对硬件解码器而言，色度小块的处理复杂度较高，具体包括以下3个方面。
1)帧内预测问题：硬件设计中为了提高处理速度，帧内预测通常一次同时处理16个像素，而2x2、2x4、4x2等色度小块包含少于16个像素，降低了帧内预测的处理性能。
2)系数编码问题：HEVC中变换系数编码基于包含16个系数的系数组(coefficient group，CG)，而2x2、2x4、4x2的色度小块包含了4个或8个变换系数，这导致需要增加包含4个系数和8个系数的系数组来支持这些小块的系数编码，因此增加了实现复杂度。
3)帧间预测问题：色度小块的帧间预测对数据带宽要求较高，也会影响解码的处理速度。
发明内容
本申请提供一种图像预测方法、装置、设备、系统及存储介质，提高了图像预测的处理性能，提升编解码的处理速度。
本申请第一方面提供一种图像预测方法，所述方法包括：
获取当前节点的划分方式；判断基于所述划分方式对所述当前节点进行划分是否会得到具有预设尺寸的图像块；所述图像块包括亮度块或色度块；在确定基于所述划分方式对所述当前节点进行划分会得到具有所述预设尺寸的图像块的情况下，对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预测。
可选的，预设尺寸的图像块可以为尺寸小于一个阈值的亮度块，该阈值可以是128、64或者32个亮度采样点数量，或者是32、16或者8个色度采样点数量。该当前节点的尺寸可以大于或者等于该阈值。
可选的，使用帧内预测可以是使用通常的帧内预测模式(intra mode)进行预测，也可以是使用IBC(intra block copy)mode进行预测。
可选的，当前节点覆盖的所有编码块指的是所有位于当前节点区域内的编码块。 其中，编码块也可以是编码单元(coding unit)。
可选的，在当前节点所在的片的类型(slice type)是帧内(Intra)类型的情况下，对所述当前节点覆盖的所有编码块使用帧内预测，而不使用帧间预测。
本申请实施例的有益效果是：本申请考虑到对当前节点对应的图像块进行划分会得到具有预设尺寸的亮度块或者色度块的情况，存在上述情况下编码端或者解码端对以当前节点为根节点进行划分或者不划分的所有编码块均使用帧内预测或者均使用帧间预测，可以实现对预设尺寸的亮度块或者色度块的并行处理，提高图像预测的处理性能，从而提升编解码性能。
可选的，以下两种情况均属于所述具有预设尺寸的图像块：具有第一预设尺寸的亮度块和具有第二预设尺寸的色度块，所述对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预测包括：判断基于所述划分方式对所述当前节点进行划分是否会得到所述具有第一预设尺寸的亮度块；在确定基于所述划分方式对当前节点进行划分会得到具有第一预设尺寸的亮度块的情况下，对所述当前节点覆盖的所有编码块使用帧内预测；在确定基于所述划分方式对当前节点进行划分不会得到具有第一预设尺寸的亮度块的情况下，对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预测。
可选的，所述在确定基于所述划分方式对当前节点进行划分不会得到具有第一预设尺寸的亮度块的情况下，对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预测，可以包括：在确定基于所述划分方式对当前节点进行划分不会得到具有第一预设尺寸的亮度块的情况下，解析所述当前节点的预测模式状态标识；在所述预测模式状态标识的值为第一值时，对所述当前节点覆盖的所有编码块使用帧间预测；或者，在所述预测模式状态标识的值为第二值时，对所述当前节点覆盖的所有编码块使用帧内预测。
结合第一方面，在第一方面的第一种可能的实现方式中，所述具有预设尺寸的图像块包括具有第一预设尺寸的亮度块，所述判断基于所述划分方式对当前节点进行划分是否会得到具有预设尺寸的图像块，包括：根据所述当前节点的尺寸和所述划分方式，确定基于所述划分方式对当前节点进行划分是否会得到具有第一预设尺寸的亮度块。
可选的，第一预设尺寸的亮度块可以为像素尺寸为4×4，或者8×8的亮度块，或者面积为16或者32的亮度块。
可选的，在该第一预设尺寸的亮度块为像素尺寸为4×4或者面积为16的情况下，根据所述当前节点的尺寸和所述划分方式，确定基于所述划分方式对当前节点进行划分是否会得到具有第一预设尺寸的亮度块，可以包括：
当前节点的亮度块的采样点数量为64，且该划分方式为四叉树划分；或者，
当前节点的亮度块的采样点数量为64，且该划分方式为三叉树划分；或者，
当前节点的亮度块的采样点数量为32，且该划分方式为二叉树划分。
结合第一方面第一种可能的实现方式，可选的，所述在确定基于所述划分方式对所述当前节点进行划分会得到具有所述预设尺寸的图像块的情况下，对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预 测，包括：在确定基于所述划分方式对当前节点进行划分会得到具有第一预设尺寸的亮度块的情况下，对所述当前节点覆盖的所有编码块使用帧内预测。
结合第一方面第一种可能的实现方式，可选的，在确定基于所述划分方式对当前节点进行划分不会得到具有第一预设尺寸的亮度块的情况下，所述方法还包括：判断基于所述划分方式对当前节点进行划分是否会得到第二预设尺寸的色度块；在确定基于所述划分方式对所述当前节点进行划分会得到具有所述第二预设尺寸的色度块的情况下，对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预测。
综上，通过上述第一种实现方式确定对以当前节点为根节点进行划分或者不划分的所有编码块均使用帧内预测，或者均使用帧间预测，可以实现对预设尺寸的亮度块或者色度块的并行处理，提高图像预测的处理性能，从而提升编解码性能。
可选的，所述具有第一预设尺寸的亮度块可以为4×4的亮度块或者面积为16的亮度块，在所述第一预设尺寸的亮度块是4×4的亮度块的情况下，第二预设尺寸的色度块可以为像素尺寸为2×4、或者4×2的色度块，或者面积为8的色度块，而不包括像素尺寸为2×2或者面积为4的色度块。
可选的，所述具有第一预设尺寸的亮度块可以为4×4的亮度块或者面积为16的亮度块，在所述第一预设尺寸的亮度块是4×4的亮度块的情况下，第二预设尺寸的色度块可以为像素尺寸为4×8、或者8×4的亮度块，或者面积为32的亮度块，而不包括像素尺寸为4×4或者面积为16的亮度块。
可选的，在第二预设尺寸的色度块为像素尺寸为2×4、或者4×2，或者面积为8的色度块，或者像素尺寸为4×8、或者8×4，或者面积为32的亮度块的情况下，判断基于所述划分方式对当前节点进行划分是否会得到第二预设尺寸的色度块，可以包括：
1)当前节点的亮度块的采样点数量为64，且该划分方式为二叉树划分；或者，
2)当前节点的亮度块的采样点数量为128，且该划分方式为三叉树划分。
结合第一方面，在第一方面的第二种可能的实现方式中，所述具有预设尺寸的图像块包括具有第二预设尺寸的色度块，所述判断基于所述划分方式对当前节点进行划分是否会得到具有预设尺寸的图像块，包括：根据所述当前节点的尺寸和划分方式，确定基于所述划分方式对当前节点进行划分是否会得到具有第二预设尺寸的色度块。
可选的，第二预设尺寸的色度块可以为像素尺寸为2×2、2×4、或者4×2，或者面积为4或者8的色度块。
可选的，所述根据所述当前节点的尺寸和划分方式，确定基于所述划分方式对当前节点进行划分是否会得到具有第二预设尺寸的色度块可以包括：根据所述当前节点的尺寸和划分方式，确定基于所述划分方式对当前节点进行划分是否会得到具有第三预设尺寸的亮度块。
可选的，该具有第三预设尺寸的亮度块可以为4×4、4×8、或者8×4，或者面积为32或者16的亮度块。
可选的，判断基于所述划分方式对当前节点进行划分是否会得到第二预设尺寸的 色度块，可以包括：
1)当前节点的亮度块的采样点数量为64，且该划分方式为四叉树划分；或者，
2)当前节点的亮度块的采样点数量为64，且该划分方式为三叉树划分；或者，
3)当前节点的亮度块的采样点数量为32，且该划分方式为二叉树划分；或者，
4)当前节点的亮度块的采样点数量为64，且该划分方式为二叉树划分；或者，
5)当前节点的亮度块的采样点数量为128，且该划分方式为三叉树划分。
可选的，第二预设尺寸的色度块可以为像素尺寸为2×4、或者4×2，或者面积为8的色度块，而不包括像素尺寸为2×2，或者面积为4的色度块。相似的，具有第三预设尺寸的亮度块可以为像素尺寸为4×8、或者8×4，或者面积为32的亮度块，而不包括像素尺寸为4×4，或者面积为16的亮度块。相应的，判断基于所述划分方式对当前节点进行划分是否会得到第二预设尺寸的色度块，可以包括：
当前节点的亮度块的采样点数量为64，且该划分方式为二叉树划分；或者，
2)当前节点的亮度块的采样点数量为128，且该划分方式为三叉树划分。
结合第一种实现方式或者基于第二种实现方式，在确定基于所述划分方式对当前节点进行划分会得到具有第二预设尺寸的色度块的情况下，所述对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预测，包括：解析所述当前节点的预测模式状态标识；在所述预测模式状态标识的值为第一值时，对所述当前节点覆盖的所有编码块使用帧间预测；或者，在所述预测模式状态标识的值为第二值时，对所述当前节点覆盖的所有编码块使用帧内预测。该实现方式应用于视频解码器，通过从码流中解析预测模式状态标识确定以当前节点为根节点进行划分或者不划分得到的所有编码块的预测模式，与现有技术相比只需解析一次，提高了视频解码的处理速度。
可选的，当前节点所在的片的类型(slice type)不是帧内(Intra)类型。
基于第一种实现方式或者基于第二种实现方式，在确定基于所述划分方式对当前节点进行划分会得到具有第二预设尺寸的色度块的情况下，所述对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预测，包括：在所述当前节点覆盖的任一编码块的预测模式为帧间预测时，对所述当前节点覆盖的所有编码块使用帧间预测；或者，在所述当前节点覆盖的任一编码块的预测模式为帧内预测时，对所述当前节点覆盖的所有编码块使用帧内预测。可选的，所述任一编码块为所述当前节点覆盖的所有编码块中的解码顺序上的第一个编码块。该实现方式应用于视频解码器，通过从码流中解析当前节点的任一一个编码块的预测模式，按照解析的预测模式对以当前节点为根节点进行划分或者不划分得到的所有编码块进行预测，与现有技术相比只需要解析一次，提高了视频解码的处理速度。
结合第二种实现方式，可选的，在确定基于所述划分方式对当前节点进行划分会得到具有第二预设尺寸的色度块的情况下，所述对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预测，包括：判断基于所述划分方式对当前节点进行划分是否会得到第一预设尺寸的亮度块；在确定基于所 述当前节点的划分方式对当前节点进行划分会得到第一预设尺寸的亮度块的情况下，对所述当前节点覆盖的所有编码块使用帧内预测。通过该实现方式确定对以当前节点为根节点进行划分或者不划分的所有编码块均使用帧内预测，可以实现对第一预设尺寸的亮度块和第二预设尺寸的色度块的并行处理，提高图像预测的处理性能，从而提升编解码性能。
可选的，在确定基于所述划分方式对当前节点进行划分不会得到第一预设尺寸的亮度块的情况下，所述对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预测，包括：解析所述当前节点的预测模式状态标识；在所述预测模式状态标识的值为第一值时，对所述当前节点覆盖的所有编码块使用帧间预测；或者，在所述预测模式状态标识的值为第二值时，对所述当前节点覆盖的所有编码块使用帧内预测。该实现方式应用于视频解码器，通过从码流中解析预测模式状态标识确定以当前节点为根节点进行划分或者不划分得到的所有编码块的预测模式，与现有技术相比只需解析一次，提高了视频解码的处理速度。
可选的，在确定基于所述划分方式对当前节点进行划分不会得到第一预设尺寸的亮度块的情况下，所述对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预测，包括：在所述当前节点覆盖的任一编码块的预测模式为帧间预测时，对所述当前节点覆盖的所有编码块使用帧间预测；或者，在所述当前节点覆盖的任一编码块的预测模式为帧内预测时，对所述当前节点覆盖的所有编码块使用帧内预测。该实现方式应用于视频解码器，通过从码流中解析当前节点的任一一个编码块的预测模式，按照解析的预测模式对以当前节点为根节点进行划分或者不划分得到的所有编码块进行预测，与现有技术相比只需要解析一次，提高了视频解码的处理速度。
可选的，所述任一编码块为所述当前节点覆盖的所有编码块中的解码顺序上的第一个编码块。
结合第一方面或者第一方面的任一种可能的实现方式，在第一方面第三种可能的实现方式中，所述对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预测，包括：按照所述划分方式对所述当前节点包括的亮度块进行划分，得到划分后的亮度块，对所述划分后的亮度块使用帧内预测，将所述当前节点包括的色度块作为色度编码块，对所述色度编码块使用帧内预测；或者，按照所述划分方式对所述当前节点包括的亮度块进行划分，得到划分后的亮度块，对所述划分后的亮度块使用帧间预测，按照所述划分方式对所述当前节点包括的色度块进行划分，得到划分后的色度块，对所述划分后的色度块使用帧间预测。该实现方式下，不论当前节点覆盖的所有编码块均使用帧内预测还是均使用帧间预测，当前节点的亮度块总是划分，当前节点的色度块在帧间预测模式时可以进行划分，当前节点的色度块在帧内预测模式时不划分。该实现方式不会产生使用帧内预测的第二预设尺寸的色度块，从而解决了色度小块帧内预测的问题，进而提高了视频编码的处理速度。
结合第一方面或者第一方面的任一种可能的实现方式，在第一方面第四种可能的实现方式中，所述对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预测，包括：按照所述划分方式对所述当前节点包括 的亮度块进行划分，得到划分后的亮度块，对所述划分后的亮度块使用帧内预测，将所述当前节点包括的色度块作为色度编码块，对所述色度编码块使用帧内预测；或者，按照所述划分方式对所述当前节点包括的亮度块进行划分，得到划分后的亮度块，对所述划分后的亮度块使用帧间预测，将所述当前节点包括的色度块作为色度编码块，对所述色度编码块使用帧间预测。该实现方式下，不论当前节点覆盖的所有编码块均使用帧内预测还是均使用帧间预测，当前节点的色度块总是不划分，亮度块按照亮度块的划分方式进行划分。该实现方式不会产生使用帧内预测的第二预设尺寸的色度块，从而解决了色度小块帧内预测的问题，进而提高了视频编码的处理速度。
结合第一方面或者第一方面的任一种可能的实现方式，在第一方面第五种可能的实现方式中，在对所述当前节点覆盖的所有编码块使用帧间预测的情况下，所述对所述当前节点覆盖的所有编码块使用帧间预测，包括：
按照所述当前节点的划分方式对所述当前节点进行划分，得到所述当前节点的子节点；根据所述当前节点的子节点的尺寸，确定所述当前节点的子节点的不被允许的划分方式；根据所述当前节点的子节点的不被允许的划分方式，确定所述当前节点的子节点的快划分策略；根据所述当前节点的子节点的块划分策略，得到所述当前节点的子节点对应的编码块，并对所述对应的编码块使用帧间预测。该实现方式下，可以避免在帧间预测的前提下产生第一预设尺寸的亮度块。
其中，该子节点可以是对当前节点划分一次得到的，也可以是划分N次得到的。N为大于1的整数。
其中，该划分策略可以包括不划分，也可以包括划分一次，也可以包括划分N次。N为大于1的整数。
本申请第二方面提供一种图像预测装置，包括：
获取模块，用于获取当前节点的划分方式；
判断模块，用于判断基于所述划分方式对所述当前节点进行划分是否会得到具有预设尺寸的图像块；所述图像块包括亮度块或色度块；
执行模块，用于在确定基于所述划分方式对所述当前节点进行划分会得到具有所述预设尺寸的图像块的情况下，对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预测。
本申请第三方面提供一种视频编码设备，包括处理器和用于存储所述处理器的可执行指令的存储器；其中所述处理器执行如本申请第一方面中所述的方法。
本申请第四方面提供一种视频解码设备，包括处理器和用于存储所述处理器的可执行指令的存储器；其中所述处理器执行如如本申请第一方面中所述的方法。
本申请第五方面提供一种图像预测系统，包括：视频采集设备、如本申请第三方面所述的视频编码设备、如本申请第四方面所述的视频解码设备以及显示设备，所述视频编码设备分别与所述视频采集设备和所述视频解码设备连接，所述视频解码设备与所述显示设备连接。
本申请第六方面提供一种计算机可读存储介质，其上存储有计算机程序，所述计算机程序被处理器执行以实现如本申请第一方面任一项所述的方法。
本申请第七方面提供一种图像预测方法，所述方法包括：
获取当前节点的划分方式，所述当前节点为当前图像中的编码树单元(coding tree unit)中的图像块；根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足第一条件；在确定所述当前节点满足所述第一条件的情况下，对所有属于当前节点的编码块使用进行帧内预测，从而得到所有属于所述当前节点的的编码块的预测值。
其中，所述当前节点的尺寸根据所述当前节点对应的编码树节点的尺寸和用于得到所述当前节点的划分方式确定得到。
其中，当前节点所在的片(slice)类型为B或者P。应理解，在当前节点所在的片(slice)类型为I的情况下，应默认对对当前节点覆盖的所有编码块使用帧内预测。
其中，可选的，所述根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足第一条件可以发生在所述当前节点小于或者等于预设的尺寸上限的情况下，预设的尺寸上限可以是256，128或者64。
其中，所述第一条件可以包括：
当前节点的亮度块的采样点数量为64，且该划分方式为四叉树划分；或者，
当前节点的亮度块的采样点数量为64，且该划分方式为三叉树划分；或者，
3)当前节点的亮度块的采样点数量为32，且该划分方式为二叉树划分。
结合第七方面，在第七方面的第一种可能的实现方式中，在确定所述当前节点不满足所述第一条件的情况下，所述方法还包括：根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足第二条件；在确定所述当前节点满足所述第二条件的情况下，对所有属于当前节点的编码块使用相同的预测方式进行预测，从而得到所有属于所述当前节点的的编码块的预测值，所述预测方式为帧内预测或者帧间预测。
其中，所述根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足第二条件，可以包括：根据所述当前节点的划分方式，所述当前节点的尺寸和当前的采样格式(Chroma format)，判断所述当前节点是否满足第二条件。
其中，第二条件可以包括：
1)当前节点的亮度块的采样点数量为64，且该划分方式为二叉树划分；
2)当前节点的亮度块的采样点数量为128，且该划分方式为三叉树划分；
3)当前节点的亮度块的采样点数量为64，且该划分方式为二叉树划分，且采样格式为4:2:0；
4)当前节点的亮度块的采样点数量为128，且该划分方式为三叉树划分，且采样格式为4:2:0；或者，
5)当前节点的子节点的色度块的宽为2。
结合第七方面第一种可能的实现方式中，在第七方面的第二种可能的实现方式中，所述对所有属于当前节点的编码块使用相同的预测方式进行预测包括：解析所述当前节点的预测模式状态标识；在所述预测模式状态标识的值为第一值的情况下，对所有属于所述当前节点的的编码块进行帧间预测；或者，在所述预测模式状态标识的值为第二值的情况下，对所有属于所述当前节点的的编码块进行帧内预测。
其中，预测模式状态标识可以为块划分过程中解析的语法元素，即是说在编码树 (coding tree)过程中解析的语法元素，当解析该语法元素时，则当前节点覆盖区域的编码单元的编码单元预测模式标志(cu_pred_mode)可以不再解析，其值为与预测模式状态标识的值对应的默认值。
结合第七方面第一种或第二种可能的实现方式中，在第七方面的第三种可能的实现方式中，所述对所有属于所述当前节点的编码块进行帧间预测，包括：按照所述当前节点的划分方式对所述当前节点进行划分，得到所述当前节点的子节点；根据所述当前节点的子节点的尺寸，确定所述当前节点的子节点的不被允许的划分方式；根据所述当前节点的子节点的不被允许的划分方式，确定所述当前节点的子节点的快划分策略；根据所述当前节点的子节点的块划分策略，得到所述当前节点的子节点对应的编码块，并对所述对应的编码块使用帧间预测。
其中，如果子节点被限制仅使用帧间预测，且子节点的亮度采样点数为32(或者节点的宽和高的乘积为32)，则子节点不允许使用二叉树划分(包括水平二叉树或竖直二叉树划分)。如果子节点被限制仅使用帧间预测，且子节点的亮度采样点数为64(或者节点的宽和高的乘积为64)，则子节点不允许使用三叉树划分(包括水平三叉树和竖直三叉树划分)。此判断方法对于视频数据格式为YUV4:2:0和YUV4:2:2均适用。
例如，如果当前节点的尺寸为8x8且使用水平二叉树(或者竖直二叉树)划分产生两个8x4(或两个4x8)的节点，8x4(或4x8)的节点继续划分会产生4x4的块，因此，8x4(或4x8)的节点不能使用竖直二叉树划分(或水平二叉树划分)，或者不能继续划分。又如，如果当前节点的亮度块的采样点数量为128，且划分方式为水平三叉树划分或者竖直三叉树划分，则可能会得到亮度块的采样点数量为64，而所述采样点数量为64的亮度节点如果使用子节点的划分方式水平三叉树或者竖直三叉树划分，会得到4x4的亮度块，因此当已经被限制仅使用帧间预测时，对于采样点数量为64的节点不能使用水平三叉树或者竖直三叉树划分，或者不能继续被划分。
结合第七方面或第七方面以上任一种可能的实现方式中，在第七方面的第四种可能的实现方式中，所述对所有属于所述当前节点的的编码块进行帧内预测，包括：按照所述划分方式对所述当前节点包括的亮度块进行划分，得到划分后的亮度块，对所述划分后的亮度块使用帧内预测，将所述当前节点包括的色度块作为色度编码块，对所述色度编码块使用帧内预测。
本申请第八方面提供一种图像预测方法，所述方法包括：获取当前节点的划分方式，所述当前节点为当前图像中的编码树单元(coding tree unit)中的图像块；根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足预设条件；在确定所述当前节点满足所述预设条件的情况下，对所有属于当前节点的编码块使用相同的预测方式进行预测，从而得到所有属于所述当前节点的的编码块的预测值，所述预测方式为帧内预测或者帧间预测。
其中，所述当前节点的尺寸可以根据所述当前节点对应的编码树节点的尺寸和用于得到所述当前节点的划分方式确定得到。
其中，根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足预设条件，可以包括：根据所述当前节点的划分方式，所述当前节点的尺寸 和当前的采样格式(Chroma format)，判断所述当前节点是否满足预设条件。
其中，预设条件可以包括：
1)当前节点的亮度块的采样点数量为64，且该划分方式为二叉树划分；或者，
2)当前节点的亮度块的采样点数量为128，且该划分方式为三叉树划分。
结合第八方面，在第八方面第一种可能的实现方式中，所述对所有属于当前节点的编码块使用相同的预测方式进行预测包括：解析所述当前节点的预测模式状态标识；在所述预测模式状态标识的值为第一值的情况下，对所有属于所述当前节点的的编码块进行帧间预测；或者，在所述预测模式状态标识的值为第二值的情况下，对所有属于所述当前节点的的编码块进行帧内预测。
结合第八方面或第八方面的第一种可能的实现方式，在第八方面第二种可能的实现方式中，所述对所有属于所述当前节点的编码块进行帧间预测，包括：按照所述当前节点的划分方式对所述当前节点进行划分，得到所述当前节点的子节点；根据所述当前节点的子节点的尺寸，确定所述当前节点的子节点的不被允许的划分方式；根据所述当前节点的子节点的不被允许的划分方式，确定所述当前节点的子节点的快划分策略；根据所述当前节点的子节点的块划分策略，得到所述当前节点的子节点对应的编码块，并对所述对应的编码块使用帧间预测。
其中，如果子节点被限制仅使用帧间预测，且子节点的亮度采样点数为32(或者节点的宽和高的乘积为32)，则子节点不允许使用二叉树划分(包括水平二叉树或竖直二叉树划分)。如果子节点被限制仅使用帧间预测，且子节点的亮度采样点数为64(或者节点的宽和高的乘积为64)，则子节点不允许使用三叉树划分(包括水平三叉树和竖直三叉树划分)。此判断方法对于视频数据格式为YUV4:2:0和YUV4:2:2均适用。
例如，如果当前节点的尺寸为8x8且使用水平二叉树(或者竖直二叉树)划分产生两个8x4(或两个4x8)的节点，8x4(或4x8)的节点继续划分会产生4x4的块，因此，8x4(或4x8)的节点不能使用竖直二叉树划分(或水平二叉树划分)，或者不能继续划分。又如，如果当前节点的亮度块的采样点数量为128，且划分方式为水平三叉树划分或者竖直三叉树划分，则可能会得到亮度块的采样点数量为64，而所述采样点数量为64的亮度节点如果使用子节点的划分方式水平三叉树或者竖直三叉树划分，会得到4x4的亮度块，因此当已经被限制仅使用帧间预测时，对于采样点数量为64的节点不能使用水平三叉树或者竖直三叉树划分，或者不能继续被划分。
本申请第九方面提供一种图像预测方法，所述方法包括：根据当前节点的尺寸和所述当前节点的预测模式，确定所述当前节点不被允许的划分方式，所述当前节点为当前图像中的编码树单元(coding tree unit)中的图像块；根据所述当前节点的不被允许的划分方式，确定所述当前节点的快划分策略；根据所述当前节点的块划分策略，得到所述当前节点对应的编码块，并对所述对应的编码块使用帧间预测。
其中，所述当前节点的尺寸可以根据所述当前节点对应的编码树节点的尺寸和用 于得到所述当前节点的划分方式确定得到。
结合第九方面，在第九方面第一种可能的实现方式中，所述根据当前节点的尺寸和所述当前节点的预测模式，确定所述当前节点不被允许的划分方式，包括：确定是否所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量是否为32；在确定所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量为32的情况下，确定二叉树划分为所述当前节点不被允许的划分方式。
结合第九方面或者第九方面第一种可能的实现方式，在第九方面第二种可能的实现方式中，所述根据当前节点的尺寸和所述当前节点的预测模式，确定所述当前节点不被允许的划分方式，包括：确定是否所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量是否为64；在确定所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量为64的情况下，确定三叉树划分为所述当前节点不被允许的划分方式。
本申请第十方面提供一种图像预测装置，所述装置包括：
获取模块，用于获取当前节点的划分方式，所述当前节点为当前图像中的编码树单元(coding tree unit)中的图像块；
判断模块，用于根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足第一条件；
执行模块，用于在确定所述当前节点满足所述第一条件的情况下，对所有属于当前节点的编码块使用进行帧内预测，从而得到所有属于所述当前节点的的编码块的预测值。
结合第十方面，在第十方面的第一种可能的实现方式中，所述判断模块还用于：在确定所述当前节点不满足所述第一条件的情况下，所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足第二条件；
所述执行模块还用于：在确定所述当前节点满足所述第二条件的情况下，对所有属于当前节点的编码块使用相同的预测方式进行预测，从而得到所有属于所述当前节点的的编码块的预测值，所述预测方式为帧内预测或者帧间预测。
其中，所述判断模块可以用于：根据所述当前节点的划分方式，所述当前节点的尺寸和当前的采样格式(Chroma format)，判断所述当前节点是否满足第二条件。
结合第十方面第一种可能的实现方式中，在第十方面的第二种可能的实现方式中，所述执行模块用于：
解析所述当前节点的预测模式状态标识；
在所述预测模式状态标识的值为第一值的情况下，对所有属于所述当前节点的的编码块进行帧间预测；或者，在所述预测模式状态标识的值为第二值的情况下，对所 有属于所述当前节点的的编码块进行帧内预测。
结合第十方面第一种或第二种可能的实现方式中，在第十方面的第三种可能的实现方式中，所述执行模块用于：
按照所述当前节点的划分方式对所述当前节点进行划分，得到所述当前节点的子节点；
根据所述当前节点的子节点的尺寸，确定所述当前节点的子节点的不被允许的划分方式；
根据所述当前节点的子节点的不被允许的划分方式，确定所述当前节点的子节点的快划分策略；
根据所述当前节点的子节点的块划分策略，得到所述当前节点的子节点对应的编码块，并对所述对应的编码块使用帧间预测。
结合第十方面或第十方面以上任一种可能的实现方式中，在第十方面的第四种可能的实现方式中，所述执行模块用于：
按照所述划分方式对所述当前节点包括的亮度块进行划分，得到划分后的亮度块，对所述划分后的亮度块使用帧内预测，将所述当前节点包括的色度块作为色度编码块，对所述色度编码块使用帧内预测。
本申请第十一方面提供一种图像预测装置，所述装置包括：获取模块，用于获取当前节点的划分方式，所述当前节点为当前图像中的编码树单元(coding tree unit)中的图像块；判断模块，用于根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足预设条件；执行模块，用于在确定所述当前节点满足所述预设条件的情况下，对所有属于当前节点的编码块使用相同的预测方式进行预测，从而得到所有属于所述当前节点的的编码块的预测值，所述预测方式为帧内预测或者帧间预测。
其中，所述判断模块，可以用于：根据所述当前节点的划分方式，所述当前节点的尺寸和当前的采样格式(Chroma format)，判断所述当前节点是否满足预设条件。
结合第十一方面，在第十一方面第一种可能的实现方式中，所所述执行模块用于：
解析所述当前节点的预测模式状态标识；
在所述预测模式状态标识的值为第一值的情况下，对所有属于所述当前节点的的编码块进行帧间预测；或者，在所述预测模式状态标识的值为第二值的情况下，对所有属于所述当前节点的的编码块进行帧内预测。
结合第十一方面或第十一方面的第一种可能的实现方式，在第十一方面第二种可能的实现方式中，所述执行模块用于：按照所述当前节点的划分方式对所述当前节点进行划分，得到所述当前节点的子节点；根据所述当前节点的子节点的尺寸，确定所 述当前节点的子节点的不被允许的划分方式；根据所述当前节点的子节点的不被允许的划分方式，确定所述当前节点的子节点的快划分策略；根据所述当前节点的子节点的块划分策略，得到所述当前节点的子节点对应的编码块，并对所述对应的编码块使用帧间预测。
本申请第十二方面提供一种图像预测装置，所述装置包括：确定单元，用于根据当前节点的尺寸和所述当前节点的预测模式，确定所述当前节点不被允许的划分方式，所述当前节点为当前图像中的编码树单元(coding tree unit)中的图像块；所述确定单元，还用于根据所述当前节点的不被允许的划分方式，确定所述当前节点的快划分策略；预测单元，用于根据所述当前节点的块划分策略，得到所述当前节点对应的编码块，并对所述对应的编码块使用帧间预测。
结合第十二方面，在第十二方面第一种可能的实现方式中，所述确定单元，用于：
确定是否所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量是否为32；
在确定所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量为32的情况下，确定二叉树划分为所述当前节点不被允许的划分方式。
结合第十二方面或者第十二方面第一种可能的实现方式，在第十二方面第二种可能的实现方式中，，所述确定单元，用于：
确定是否所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量是否为64；
在确定所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量为64的情况下，确定三叉树划分为所述当前节点不被允许的划分方式。
本申请第七，第八以及第九方面中的特征和实现方式可以参考第一方面的方法的特征和实现方式。
本申请第七方面的方法可由本申请第十方面的装置执行。本申请第十方面的装置的功能性及其不同实现方式可以参考本申请第七方面的方法的特征和实现方式。
本申请第八方面的方法可由本申请第十一方面的装置执行。本申请第十一方面的装置的功能性及其不同实现方式可以参考本申请第八方面的方法的特征和实现方式。
本申请第九方面的方法可由本申请第十二方面的装置执行。本申请第十二方面的装置的功能性及其不同实现方式可以参考本申请第九方面的方法的特征和实现方式
本申请第十三方面提供一种解码视频流的装置，包含处理器和存储器。所述存储器存储指令，所述指令使得所述处理器执行根据第七方面或第八方面或第九方面的方法。
本申请第十四方面提供一种编码视频流的装置，包含处理器和存储器。所述存储器存储指令，所述指令使得所述处理器执行根据第七方面或第八方面或第九方面的方法。
本申请第十五方面提供一种计算机可读存储介质，其上储存有指令，所述指令执行时，使得一个或多个处理器编码视频数据。所述指令使得所述一个或多个处理器执行根据第七方面或第八方面或第九方面，或第七方面或第八方面或第九方面任何可能的实现方式。
本申请第十六方面提供一种包括程序代码的计算机程序，所述程序代码在计算机上运行时执行根据第七方面或第八方面或第九方面，或第七方面或第八方面或第九方面任何可能的实现方式。
本申请第十七方面提供一种计算机可读存储介质，其上存储有码流，所述码流携带当前编码树的当前节点的预测模式状态标识；所述预测模式状态标识的值为第一值的用于指示所有属于所述当前节点的的编码块的预测模式为帧间预测；或者，所述预测模式状态标识的值为第二值用于指示所有属于所述当前节点的的编码块的预测模式为帧内预测。
应当理解的是，本申请的第二至第十七方面与本申请的第一方面的技术方案一致，各方面及对应的可行实施方式所取得的有益效果相似，不再赘述。
在附图及以下说明中阐述一个或多个实施例的细节。其它特征、目的和优点通过说明书、附图以及权利要求是显而易见的。
本申请提供一种图像预测方法、装置、设备、系统及存储介质。该方法包括：获取当前节点的划分方式，判断基于当前节点的划分方式对当前节点进行划分是否会得到具有预设尺寸的图像块，其中图像块包括亮度块或色度块。在基于当前节点的划分方式对当前节点进行划分会得到具有预设尺寸的图像块的情况下，对当前节点覆盖的所有编码块使用帧内预测，或者对当前节点覆盖的所有编码块使用帧间预测。上述方法对当前节点的所有编码块均使用帧内或者均使用帧间预测，可以实现对当前节点的所有编码块的并行处理，提高图像预测的处理性能，从而提升编解码的处理速度。
附图说明
图1A是用于实现本申请实施例的视频编码及解码系统10实例的框图；
图1B是用于实现本申请实施例的视频译码系统40实例的框图；
图2是用于实现本申请实施例的编码器20实例结构的框图；
图3是用于实现本申请实施例的解码器30实例结构的框图；
图4是用于实现本申请实施例的视频译码设备400实例的框图；
图5是用于实现本申请实施例的另一种编码装置或解码装置实例的框图；
图6是用于实现本申请实施例的一种块划分方式的示意性框图；
图7是用于实现本申请实施例的一种帧内预测的示意性框图；
图8是用于实现本申请实施例的一种视频通信系统示意性框图；
图9是本申请实施例提供的第一种图像预测方法的流程示意图；
图10是本申请实施例提供的第二种图像预测方法的流程示意图；
图11是本申请实施例提供的第三种图像预测方法的流程示意图；
图12是本申请实施例提供的第四种图像预测方法的流程示意图；
图13是本申请实施例提供的第五种图像预测方法的流程示意图；
图14是本申请实施例提供的第六种图像预测方法的流程示意图；
图15是本申请实施例提供的图像预测装置的功能结构示意图；
图16是本申请实施例提供的视频编码设备的硬件结构示意图；
图17是本申请实施例提供的视频解码设备的硬件结构示意图；
图18是本申请实施例提供的图像预测系统的结构示意图。
具体实施方式
下面结合本申请实施例中的附图对本申请实施例进行描述。以下描述中，参考形成本公开一部分并以说明之方式示出本申请实施例的具体方面或可使用本申请实施例的具体方面的附图。应理解，本申请实施例可在其它方面中使用，并可包括附图中未描绘的结构或逻辑变化。因此，以下详细描述不应以限制性的意义来理解，且本申请的范围由所附权利要求书界定。例如，应理解，结合所描述方法的揭示内容可以同样适用于用于执行所述方法的对应设备或系统，且反之亦然。例如，如果描述一个或多个具体方法步骤，则对应的设备可以包含如功能单元等一个或多个单元，来执行所描述的一个或多个方法步骤(例如，一个单元执行一个或多个步骤，或多个单元，其中每个都执行多个步骤中的一个或多个)，即使附图中未明确描述或说明这种一个或多个单元。另一方面，例如，如果基于如功能单元等一个或多个单元描述具体装置，则对应的方法可以包含一个步骤来执行一个或多个单元的功能性(例如，一个步骤执行一个或多个单元的功能性，或多个步骤，其中每个执行多个单元中一个或多个单元的功能性)，即使附图中未明确描述或说明这种一个或多个步骤。进一步，应理解的是，除非另外明确提出，本文中所描述的各示例性实施例和/或方面的特征可以相互组合。
视频编码通常是指处理形成视频或视频序列的图片序列。在视频编码领域，术语“图片(picture)”、“帧(frame)”或“图像(image)”可以用作同义词。本文中使用的视频编码表示视频编码或视频解码。视频编码在源侧执行，通常包括处理(例如，通过压缩)原始视频图片以减少表示该视频图片所需的数据量，从而更高效地存储和/或传输。视频解码在目的地侧执行，通常包括相对于编码器作逆处理，以重构视频图片。实施例涉及的视频图片“编码”应理解为涉及视频序列的“编码”或“解码”。 编码部分和解码部分的组合也称为编解码(编码和解码)。
视频序列包括一系列图像(picture)，图像被进一步划分为切片(slice)，切片再被划分为块(block)。视频编码以块为单位进行编码处理，在一些新的视频编码标准中，块的概念被进一步扩展。比如，宏块可进一步划分成多个可用于预测编码的预测块(partition)。或者，采用编码单元(coding unit，CU)，预测单元(prediction unit，PU)和变换单元(transform unit，TU)等基本概念，从功能上划分了多种块单元，并采用全新的基于树结构进行描述。比如CU可以按照四叉树进行划分为更小的CU，而更小的CU还可以继续划分，从而形成一种四叉树结构，CU是对编码图像进行划分和编码的基本单元。对于PU和TU也有类似的树结构，PU可以对应预测块，是预测编码的基本单元。对CU按照划分模式进一步划分成多个PU。TU可以对应变换块，是对预测残差进行变换的基本单元。然而，无论CU，PU还是TU，本质上都属于块(或称图像块)的概念。
通过使用表示为编码树的四叉树结构将CTU拆分为多个CU。在CU层级处作出是否使用图片间(时间)或图片内(空间)预测对图片区域进行编码的决策。每个CU可以根据PU拆分类型进一步拆分为一个、两个或四个PU。一个PU内应用相同的预测过程，并在PU基础上将相关信息传输到解码器。在通过基于PU拆分类型应用预测过程获取残差块之后，可以根据类似于用于CU的编码树的其它四叉树结构将CU分割成变换单元(transform unit，TU)。在视频压缩技术最新的发展中，使用四叉树和二叉树(Quad-tree and binary tree，QTBT)分割帧来分割编码块。在QTBT块结构中，CU可以为正方形或矩形形状。
本文中，为了便于描述和理解，可将当前编码图像中待编码的图像块称为当前块，例如在编码中，指当前正在编码的块；在解码中，指当前正在解码的块。将参考图像中用于对当前块进行预测的已解码的图像块称为参考块，即参考块是为当前块提供参考信号的块，其中，参考信号表示图像块内的像素值。可将参考图像中为当前块提供预测信号的块为预测块，其中，预测信号表示预测块内的像素值或者采样值或者采样信号。例如，在遍历多个参考块以后，找到了最佳参考块，此最佳参考块将为当前块提供预测，此块称为预测块。
无损视频编码情况下，可以重构原始视频图片，即经重构视频图片具有与原始视频图片相同的质量(假设存储或传输期间没有传输损耗或其它数据丢失)。在有损视频编码情况下，通过例如量化执行进一步压缩，来减少表示视频图片所需的数据量，而解码器侧无法完全重构视频图片，即经重构视频图片的质量相比原始视频图片的质量较低或较差。
H.261的几个视频编码标准属于“有损混合型视频编解码”(即，将样本域中的空间和时间预测与变换域中用于应用量化的2D变换编码结合)。视频序列的每个图片通常分割成不重叠的块集合，通常在块层级上进行编码。换句话说，编码器侧通常在块(视频块)层级处理亦即编码视频，例如，通过空间(图片内)预测和时间(图片间)预测来产生预测块，从当前块(当前处理或待处理的块)减去预测块以获取残差块，在变换域变换残差块并量化残差块，以减少待传输(压缩)的数据量，而解码器侧将相对于编码器的逆处理部分应用于经编码或经压缩块，以重构用于表示的当前 块。另外，编码器复制解码器处理循环，使得编码器和解码器生成相同的预测(例如帧内预测和帧间预测)和/或重构，用于处理亦即编码后续块。
下面描述本申请实施例所应用的系统架构。参见图1A，图1A示例性地给出了本申请实施例所应用的视频编码及解码系统10的示意性框图。如图1A所示，视频编码及解码系统10可包括源设备12和目的地设备14，源设备12产生经编码视频数据，因此，源设备12可被称为视频编码装置。目的地设备14可对由源设备12所产生的经编码的视频数据进行解码，因此，目的地设备14可被称为视频解码装置。源设备12、目的地设备14或两个的各种实施方案可包含一或多个处理器以及耦合到所述一或多个处理器的存储器。所述存储器可包含但不限于RAM、ROM、EEPROM、快闪存储器或可用于以可由计算机存取的指令或数据结构的形式存储所要的程序代码的任何其它媒体，如本文所描述。源设备12和目的地设备14可以包括各种装置，包含桌上型计算机、移动计算装置、笔记型(例如，膝上型)计算机、平板计算机、机顶盒、例如所谓的“智能”电话等电话手持机、电视机、相机、显示装置、数字媒体播放器、视频游戏控制台、车载计算机、无线通信设备或其类似者。
虽然图1A将源设备12和目的地设备14绘示为单独的设备，但设备实施例也可以同时包括源设备12和目的地设备14或同时包括两者的功能性，即源设备12或对应的功能性以及目的地设备14或对应的功能性。在此类实施例中，可以使用相同硬件和/或软件，或使用单独的硬件和/或软件，或其任何组合来实施源设备12或对应的功能性以及目的地设备14或对应的功能性。
源设备12和目的地设备14之间可通过链路13进行通信连接，目的地设备14可经由链路13从源设备12接收经编码视频数据。链路13可包括能够将经编码视频数据从源设备12移动到目的地设备14的一或多个媒体或装置。在一个实例中，链路13可包括使得源设备12能够实时将经编码视频数据直接发射到目的地设备14的一或多个通信媒体。在此实例中，源设备12可根据通信标准(例如无线通信协议)来调制经编码视频数据，且可将经调制的视频数据发射到目的地设备14。所述一或多个通信媒体可包含无线和/或有线通信媒体，例如射频(RF)频谱或一或多个物理传输线。所述一或多个通信媒体可形成基于分组的网络的一部分，基于分组的网络例如为局域网、广域网或全球网络(例如，因特网)。所述一或多个通信媒体可包含路由器、交换器、基站或促进从源设备12到目的地设备14的通信的其它设备。
源设备12包括编码器20，另外可选地，源设备12还可以包括图片源16、图片预处理器18、以及通信接口22。具体实现形态中，所述编码器20、图片源16、图片预处理器18、以及通信接口22可能是源设备12中的硬件部件，也可能是源设备12中的软件程序。分别描述如下：
图片源16，可以包括或可以为任何类别的图片捕获设备，用于例如捕获现实世界图片，和/或任何类别的图片或评论(对于屏幕内容编码，屏幕上的一些文字也认为是待编码的图片或图像的一部分)生成设备，例如，用于生成计算机动画图片的计算机图形处理器，或用于获取和/或提供现实世界图片、计算机动画图片(例如，屏幕内容、虚拟现实(virtual reality，VR)图片)的任何类别设备，和/或其任何组合(例如，实景(augmented reality，AR)图片)。图片源16可以为用于捕获图片的相机或者用于 存储图片的存储器，图片源16还可以包括存储先前捕获或产生的图片和/或获取或接收图片的任何类别的(内部或外部)接口。当图片源16为相机时，图片源16可例如为本地的或集成在源设备中的集成相机；当图片源16为存储器时，图片源16可为本地的或例如集成在源设备中的集成存储器。当所述图片源16包括接口时，接口可例如为从外部视频源接收图片的外部接口，外部视频源例如为外部图片捕获设备，比如相机、外部存储器或外部图片生成设备，外部图片生成设备例如为外部计算机图形处理器、计算机或服务器。接口可以为根据任何专有或标准化接口协议的任何类别的接口，例如有线或无线接口、光接口。
其中，图片可以视为像素点(picture element)的二维阵列或矩阵。阵列中的像素点也可以称为采样点。阵列或图片在水平和垂直方向(或轴线)上的采样点数目定义图片的尺寸和/或分辨率。为了表示颜色，通常采用三个颜色分量，即图片可以表示为或包含三个采样阵列。例如在RBG格式或颜色空间中，图片包括对应的红色、绿色及蓝色采样阵列。但是，在视频编码中，每个像素通常以亮度/色度格式或颜色空间表示，例如对于YUV格式的图片，包括Y指示的亮度分量(有时也可以用L指示)以及U和V指示的两个色度分量。亮度(luma)分量Y表示亮度或灰度水平强度(例如，在灰度等级图片中两者相同)，而两个色度(chroma)分量U和V表示色度或颜色信息分量。相应地，YUV格式的图片包括亮度采样值(Y)的亮度采样阵列，和色度值(U和V)的两个色度采样阵列。RGB格式的图片可以转换或变换为YUV格式，反之亦然，该过程也称为色彩变换或转换。如果图片是黑白的，该图片可以只包括亮度采样阵列。本申请实施例中，由图片源16传输至图片处理器的图片也可称为原始图片数据17。
图片预处理器18，用于接收原始图片数据17并对原始图片数据17执行预处理，以获取经预处理的图片19或经预处理的图片数据19。例如，图片预处理器18执行的预处理可以包括整修、色彩格式转换(例如，从RGB格式转换为YUV格式)、调色或去噪。
编码器20(或称视频编码器20)，用于接收经预处理的图片数据19，采用相关预测模式(如本文各个实施例中的预测模式)对经预处理的图片数据19进行处理，从而提供经编码图片数据21(下文将进一步基于图2或图4或图5描述编码器20的结构细节)。在一些实施例中，编码器20可以用于执行后文所描述的各个实施例，以实现本申请所描述的色度块预测方法在编码侧的应用。
通信接口22，可用于接收经编码图片数据21，并可通过链路13将经编码图片数据21传输至目的地设备14或任何其它设备(如存储器)，以用于存储或直接重构，所述其它设备可为任何用于解码或存储的设备。通信接口22可例如用于将经编码图片数据21封装成合适的格式，例如数据包，以在链路13上传输。
目的地设备14包括解码器30，另外可选地，目的地设备14还可以包括通信接口28、图片后处理器32和显示设备34。分别描述如下：
通信接口28，可用于从源设备12或任何其它源接收经编码图片数据21，所述任何其它源例如为存储设备，存储设备例如为经编码图片数据存储设备。通信接口28可以用于藉由源设备12和目的地设备14之间的链路13或藉由任何类别的网络传输或 接收经编码图片数据21，链路13例如为直接有线或无线连接，任何类别的网络例如为有线或无线网络或其任何组合，或任何类别的私网和公网，或其任何组合。通信接口28可以例如用于解封装通信接口22所传输的数据包以获取经编码图片数据21。
通信接口28和通信接口22都可以配置为单向通信接口或者双向通信接口，以及可以用于例如发送和接收消息来建立连接、确认和交换任何其它与通信链路和/或例如经编码图片数据传输的数据传输有关的信息。
解码器30(或称为解码器30)，用于接收经编码图片数据21并提供经解码图片数据31或经解码图片31(下文将进一步基于图3或图4或图5描述解码器30的结构细节)。在一些实施例中，解码器30可以用于执行后文所描述的各个实施例，以实现本申请所描述的色度块预测方法在解码侧的应用。
图片后处理器32，用于对经解码图片数据31(也称为经重构图片数据)执行后处理，以获得经后处理图片数据33。图片后处理器32执行的后处理可以包括：色彩格式转换(例如，从YUV格式转换为RGB格式)、调色、整修或重采样，或任何其它处理，还可用于将将经后处理图片数据33传输至显示设备34。
显示设备34，用于接收经后处理图片数据33以向例如用户或观看者显示图片。显示设备34可以为或可以包括任何类别的用于呈现经重构图片的显示器，例如，集成的或外部的显示器或监视器。例如，显示器可以包括液晶显示器(liquid crystal display，LCD)、有机发光二极管(organic light emitting diode，OLED)显示器、等离子显示器、投影仪、微LED显示器、硅基液晶(liquid crystal on silicon，LCoS)、数字光处理器(digital light processor，DLP)或任何类别的其它显示器。
虽然，图1A将源设备12和目的地设备14绘示为单独的设备，但设备实施例也可以同时包括源设备12和目的地设备14或同时包括两者的功能性，即源设备12或对应的功能性以及目的地设备14或对应的功能性。在此类实施例中，可以使用相同硬件和/或软件，或使用单独的硬件和/或软件，或其任何组合来实施源设备12或对应的功能性以及目的地设备14或对应的功能性。
本领域技术人员基于描述明显可知，不同单元的功能性或图1A所示的源设备12和/或目的地设备14的功能性的存在和(准确)划分可能根据实际设备和应用有所不同。源设备12和目的地设备14可以包括各种设备中的任一个，包含任何类别的手持或静止设备，例如，笔记本或膝上型计算机、移动电话、智能手机、平板或平板计算机、摄像机、台式计算机、机顶盒、电视机、相机、车载设备、显示设备、数字媒体播放器、视频游戏控制台、视频流式传输设备(例如内容服务服务器或内容分发服务器)、广播接收器设备、广播发射器设备等，并可以不使用或使用任何类别的操作系统。
编码器20和解码器30都可以实施为各种合适电路中的任一个，例如，一个或多个微处理器、数字信号处理器(digital signal processor，DSP)、专用集成电路(application-specific integrated circuit，ASIC)、现场可编程门阵列(field-programmable gate array，FPGA)、离散逻辑、硬件或其任何组合。如果部分地以软件实施所述技术，则设备可将软件的指令存储于合适的非暂时性计算机可读存储介质中，且可使用一或多个处理器以硬件执行指令从而执行本公开的技术。前述内容(包含硬件、软件、硬 件与软件的组合等)中的任一者可视为一或多个处理器。
在一些情况下，图1A中所示视频编码及解码系统10仅为示例，本申请的技术可以适用于不必包含编码和解码设备之间的任何数据通信的视频编码设置(例如，视频编码或视频解码)。在其它实例中，数据可从本地存储器检索、在网络上流式传输等。视频编码设备可以对数据进行编码并且将数据存储到存储器，和/或视频解码设备可以从存储器检索数据并且对数据进行解码。在一些实例中，由并不彼此通信而是仅编码数据到存储器和/或从存储器检索数据且解码数据的设备执行编码和解码。
参见图1B，图1B是根据一示例性实施例的包含图2的编码器20和/或图3的解码器30的视频译码系统40的实例的说明图。视频译码系统40可以实现本申请实施例的各种技术的组合。在所说明的实施方式中，视频译码系统40可以包含成像设备41、编码器20、解码器30(和/或藉由处理单元46的逻辑电路47实施的视频编/解码器)、天线42、一个或多个处理器43、一个或多个存储器44和/或显示设备45。
如图1B所示，成像设备41、天线42、处理单元46、逻辑电路47、编码器20、解码器30、处理器43、存储器44和/或显示设备45能够互相通信。如所论述，虽然用编码器20和解码器30绘示视频译码系统40，但在不同实例中，视频译码系统40可以只包含编码器20或只包含解码器30。
在一些实例中，天线42可以用于传输或接收视频数据的经编码比特流。另外，在一些实例中，显示设备45可以用于呈现视频数据。在一些实例中，逻辑电路47可以通过处理单元46实施。处理单元46可以包含专用集成电路(application-specific integrated circuit，ASIC)逻辑、图形处理器、通用处理器等。视频译码系统40也可以包含可选的处理器43，该可选处理器43类似地可以包含专用集成电路(application-specific integrated circuit，ASIC)逻辑、图形处理器、通用处理器等。在一些实例中，逻辑电路47可以通过硬件实施，如视频编码专用硬件等，处理器43可以通过通用软件、操作系统等实施。另外，存储器44可以是任何类型的存储器，例如易失性存储器(例如，静态随机存取存储器(Static Random Access Memory，SRAM)、动态随机存储器(Dynamic Random Access Memory，DRAM)等)或非易失性存储器(例如，闪存等)等。在非限制性实例中，存储器44可以由超速缓存内存实施。在一些实例中，逻辑电路47可以访问存储器44(例如用于实施图像缓冲器)。在其它实例中，逻辑电路47和/或处理单元46可以包含存储器(例如，缓存等)用于实施图像缓冲器等。
在一些实例中，通过逻辑电路实施的编码器20可以包含(例如，通过处理单元46或存储器44实施的)图像缓冲器和(例如，通过处理单元46实施的)图形处理单元。图形处理单元可以通信耦合至图像缓冲器。图形处理单元可以包含通过逻辑电路47实施的编码器20，以实施参照图2和/或本文中所描述的任何其它编码器系统或子系统所论述的各种模块。逻辑电路可以用于执行本文所论述的各种操作。
在一些实例中，解码器30可以以类似方式通过逻辑电路47实施，以实施参照图3的解码器30和/或本文中所描述的任何其它解码器系统或子系统所论述的各种模块。在一些实例中，逻辑电路实施的解码器30可以包含(通过处理单元2820或存储器44 实施的)图像缓冲器和(例如，通过处理单元46实施的)图形处理单元。图形处理单元可以通信耦合至图像缓冲器。图形处理单元可以包含通过逻辑电路47实施的解码器30，以实施参照图3和/或本文中所描述的任何其它解码器系统或子系统所论述的各种模块。
在一些实例中，天线42可以用于接收视频数据的经编码比特流。如所论述，经编码比特流可以包含本文所论述的与编码视频帧相关的数据、指示符、索引值、模式选择数据等，例如与编码分割相关的数据(例如，变换系数或经量化变换系数，(如所论述的)可选指示符，和/或定义编码分割的数据)。视频译码系统40还可包含耦合至天线42并用于解码经编码比特流的解码器30。显示设备45用于呈现视频帧。
应理解，本申请实施例中对于参考编码器20所描述的实例，解码器30可以用于执行相反过程。关于信令语法元素，解码器30可以用于接收并解析这种语法元素，相应地解码相关视频数据。在一些例子中，编码器20可以将语法元素熵编码成经编码视频比特流。在此类实例中，解码器30可以解析这种语法元素，并相应地解码相关视频数据。
需要说明的是，本申请实施例描述的解码方法主要用于解码过程，此过程在编码器20和解码器30均存在。
参见图2，图2示出用于实现本申请实施例的编码器20的实例的示意性/概念性框图。在图2的实例中，编码器20包括残差计算单元204、变换处理单元206、量化单元208、逆量化单元210、逆变换处理单元212、重构单元214、缓冲器216、环路滤波器单元220、经解码图片缓冲器(decoded picture buffer，DPB)230、预测处理单元260和熵编码单元270。预测处理单元260可以包含帧间预测单元244、帧内预测单元254和模式选择单元262。帧间预测单元244可以包含运动估计单元和运动补偿单元(未图示)。图2所示的编码器20也可以称为混合型视频编码器或根据混合型视频编解码器的视频编码器。
例如，残差计算单元204、变换处理单元206、量化单元208、预测处理单元260和熵编码单元270形成编码器20的前向信号路径，而例如逆量化单元210、逆变换处理单元212、重构单元214、缓冲器216、环路滤波器220、经解码图片缓冲器(decoded picture buffer，DPB)230、预测处理单元260形成编码器的后向信号路径，其中编码器的后向信号路径对应于解码器的信号路径(参见图3中的解码器30)。
编码器20通过例如输入202，接收图片201或图片201的图像块203，例如，形成视频或视频序列的图片序列中的图片。图像块203也可以称为当前图片块或待编码图片块，图片201可以称为当前图片或待编码图片(尤其是在视频编码中将当前图片与其它图片区分开时，其它图片例如同一视频序列亦即也包括当前图片的视频序列中的先前经编码和/或经解码图片)。
编码器20的实施例可以包括分割单元(图2中未绘示)，用于将图片201分割成多个例如图像块203的块，通常分割成多个不重叠的块。分割单元可以用于对视频序列中所有图片使用相同的块大小以及定义块大小的对应栅格，或用于在图片或子集或图片群组之间更改块大小，并将每个图片分割成对应的块。
在一个实例中，编码器20的预测处理单元260可以用于执行上述分割技术的任何 组合。
如图片201，图像块203也是或可以视为具有采样值的采样点的二维阵列或矩阵，虽然其尺寸比图片201小。换句话说，图像块203可以包括，例如，一个采样阵列(例如黑白图片201情况下的亮度阵列)或三个采样阵列(例如，彩色图片情况下的一个亮度阵列和两个色度阵列)或依据所应用的色彩格式的任何其它数目和/或类别的阵列。图像块203的水平和垂直方向(或轴线)上采样点的数目定义图像块203的尺寸。
如图2所示的编码器20用于逐块编码图片201，例如，对每个图像块203执行编码和预测。
残差计算单元204用于基于图片图像块203和预测块265(下文提供预测块265的其它细节)计算残差块205，例如，通过逐样本(逐像素)将图片图像块203的样本值减去预测块265的样本值，以在样本域中获取残差块205。
变换处理单元206用于在残差块205的样本值上应用例如离散余弦变换(discrete cosine transform，DCT)或离散正弦变换(discrete sine transform，DST)的变换，以在变换域中获取变换系数207。变换系数207也可以称为变换残差系数，并在变换域中表示残差块205。
变换处理单元206可以用于应用DCT/DST的整数近似值，例如为AVS，AVS2，AVS3指定的变换。与正交DCT变换相比，这种整数近似值通常由某一因子按比例缩放。为了维持经正变换和逆变换处理的残差块的范数，应用额外比例缩放因子作为变换过程的一部分。比例缩放因子通常是基于某些约束条件选择的，例如，比例缩放因子是用于移位运算的2的幂、变换系数的位深度、准确性和实施成本之间的权衡等。例如，在解码器30侧通过例如逆变换处理单元212为逆变换(以及在编码器20侧通过例如逆变换处理单元212为对应逆变换)指定具体比例缩放因子，以及相应地，可以在编码器20侧通过变换处理单元206为正变换指定对应比例缩放因子。
量化单元208用于例如通过应用标量量化或向量量化来量化变换系数207，以获取经量化变换系数209。经量化变换系数209也可以称为经量化残差系数209。量化过程可以减少与部分或全部变换系数207有关的位深度。例如，可在量化期间将n位变换系数向下舍入到m位变换系数，其中n大于m。可通过调整量化参数(quantization parameter，QP)修改量化程度。例如，对于标量量化，可以应用不同的标度来实现较细或较粗的量化。较小量化步长对应较细量化，而较大量化步长对应较粗量化。可以通过量化参数(quantization parameter，QP)指示合适的量化步长。例如，量化参数可以为合适的量化步长的预定义集合的索引。例如，较小的量化参数可以对应精细量化(较小量化步长)，较大量化参数可以对应粗糙量化(较大量化步长)，反之亦然。量化可以包含除以量化步长以及例如通过逆量化210执行的对应的量化或逆量化，或者可以包含乘以量化步长。根据例如AVS，AVS2，AVS3的一些标准的实施例可以使用量化参数来确定量化步长。一般而言，可以基于量化参数使用包含除法的等式的定点近似来计算量化步长。可以引入额外比例缩放因子来进行量化和反量化，以恢复可能由于在用于量化步长和量化参数的等式的定点近似中使用的标度而修改的残差块的范数。在一个实例实施方式中，可以合并逆变换和反量化的标度。或者，可以使用自定义量化表并在例如比特流中将其从编码器通过信号发送到解码器。量化是有损操作， 其中量化步长越大，损耗越大。
逆量化单元210用于在经量化系数上应用量化单元208的逆量化，以获取经反量化系数211，例如，基于或使用与量化单元208相同的量化步长，应用量化单元208应用的量化方案的逆量化方案。经反量化系数211也可以称为经反量化残差系数211，对应于变换系数207，虽然由于量化造成的损耗通常与变换系数不相同。
逆变换处理单元212用于应用变换处理单元206应用的变换的逆变换，例如，逆离散余弦变换(discrete cosine transform，DCT)或逆离散正弦变换(discrete sine transform，DST)，以在样本域中获取逆变换块213。逆变换块213也可以称为逆变换经反量化块213或逆变换残差块213。
重构单元214(例如，求和器214)用于将逆变换块213(即经重构残差块213)添加至预测块265，以在样本域中获取经重构块215，例如，将经重构残差块213的样本值与预测块265的样本值相加。
可选地，例如线缓冲器216的缓冲器单元216(或简称“缓冲器”216)用于缓冲或存储经重构块215和对应的样本值，用于例如帧内预测。在其它的实施例中，编码器可以用于使用存储在缓冲器单元216中的未经滤波的经重构块和/或对应的样本值来进行任何类别的估计和/或预测，例如帧内预测。
例如，编码器20的实施例可以经配置以使得缓冲器单元216不只用于存储用于帧内预测254的经重构块215，也用于环路滤波器单元220(在图2中未示出)，和/或，例如使得缓冲器单元216和经解码图片缓冲器单元230形成一个缓冲器。其它实施例可以用于将经滤波块221和/或来自经解码图片缓冲器230的块或样本(图2中均未示出)用作帧内预测254的输入或基础。
环路滤波器单元220(或简称“环路滤波器”220)用于对经重构块215进行滤波以获取经滤波块221，从而顺利进行像素转变或提高视频质量。环路滤波器单元220旨在表示一个或多个环路滤波器，例如去块滤波器、样本自适应偏移(sample-adaptive offset，SAO)滤波器或其它滤波器，例如双边滤波器、自适应环路滤波器(adaptive loop filter，ALF)，或锐化或平滑滤波器，或协同滤波器。尽管环路滤波器单元220在图2中示出为环内滤波器，但在其它配置中，环路滤波器单元220可实施为环后滤波器。经滤波块221也可以称为经滤波的经重构块221。经解码图片缓冲器230可以在环路滤波器单元220对经重构编码块执行滤波操作之后存储经重构编码块。
编码器20(对应地，环路滤波器单元220)的实施例可以用于输出环路滤波器参数(例如，样本自适应偏移信息)，例如，直接输出或由熵编码单元270或任何其它熵编码单元熵编码后输出，例如使得解码器30可以接收并应用相同的环路滤波器参数用于解码。
经解码图片缓冲器(decoded picture buffer，DPB)230可以为存储参考图片数据供编码器20编码视频数据之用的参考图片存储器。DPB 230可由多种存储器设备中的任一个形成，例如动态随机存储器(dynamic random access memory，DRAM)(包含同步DRAM(synchronous DRAM，SDRAM)、磁阻式RAM(magnetoresistive RAM，MRAM)、电阻式RAM(resistive RAM，RRAM))或其它类型的存储器设备。可以由同一存储器设备或单独的存储器设备提供DPB 230和缓冲器216。在某一实例中， 经解码图片缓冲器(decoded picture buffer，DPB)230用于存储经滤波块221。经解码图片缓冲器230可以进一步用于存储同一当前图片或例如先前经重构图片的不同图片的其它先前的经滤波块，例如先前经重构和经滤波块221，以及可以提供完整的先前经重构亦即经解码图片(和对应参考块和样本)和/或部分经重构当前图片(和对应参考块和样本)，例如用于帧间预测。在某一实例中，如果经重构块215无需环内滤波而得以重构，则经解码图片缓冲器(decoded picture buffer，DPB)230用于存储经重构块215。
预测处理单元260，也称为块预测处理单元260，用于接收或获取图像块203(当前图片201的当前图像块203)和经重构图片数据，例如来自缓冲器216的同一(当前)图片的参考样本和/或来自经解码图片缓冲器230的一个或多个先前经解码图片的参考图片数据231，以及用于处理这类数据进行预测，即提供可以为经帧间预测块245或经帧内预测块255的预测块265。
模式选择单元262可以用于选择预测模式(例如帧内或帧间预测模式)和/或对应的用作预测块265的预测块245或255，以计算残差块205和重构经重构块215。
模式选择单元262的实施例可以用于选择预测模式(例如，从预测处理单元260所支持的那些预测模式中选择)，所述预测模式提供最佳匹配或者说最小残差(最小残差意味着传输或存储中更好的压缩)，或提供最小信令开销(最小信令开销意味着传输或存储中更好的压缩)，或同时考虑或平衡以上两者。模式选择单元262可以用于基于码率失真优化(rate distortion optimization，RDO)确定预测模式，即选择提供最小码率失真优化的预测模式，或选择相关码率失真至少满足预测模式选择标准的预测模式。
下文将详细解释编码器20的实例(例如，通过预测处理单元260)执行的预测处理和(例如，通过模式选择单元262)执行的模式选择。
如上文所述，编码器20用于从(预先确定的)预测模式集合中确定或选择最好或最优的预测模式。预测模式集合可以包括例如帧内预测模式和/或帧间预测模式。
帧内预测模式集合可以包括35种不同的帧内预测模式，例如，如DC(或均值)模式和平面模式的非方向性模式，或如H.265中定义的方向性模式，或者可以包括67种不同的帧内预测模式，例如，如DC(或均值)模式和平面模式的非方向性模式，或如正在发展中的H.266中定义的方向性模式。
在可能的实现中，帧间预测模式集合取决于可用参考图片(即，例如前述存储在DBP 230中的至少部分经解码图片)和其它帧间预测参数，例如取决于是否使用整个参考图片或只使用参考图片的一部分，例如围绕当前块的区域的搜索窗区域，来搜索最佳匹配参考块，和/或例如取决于是否应用如半像素和/或四分之一像素内插的像素内插，帧间预测模式集合例如可包括先进运动矢量(Advanced Motion Vector Prediction，AMVP)模式和融合(merge)模式。具体实施中，帧间预测模式集合可包括本申请实施例改进的基于控制点的AMVP模式，以及，改进的基于控制点的merge模式。在一个实例中，帧内预测单元254可以用于执行下文描述的帧间预测技术的任意组合。
除了以上预测模式，本申请实施例也可以应用跳过模式和/或直接模式。
预测处理单元260可以进一步用于将图像块203分割成较小的块分区或子块，例 如，通过迭代使用四叉树(quad-tree，QT)分割、二进制树(binary-tree，BT)分割或三叉树(triple-tree，TT)或者扩展四叉树(EQT,Extended Quad-Tree)分割，或其任何组合，以及用于例如为块分区或子块中的每一个执行预测，其中模式选择包括选择分割的图像块203的树结构和选择应用于块分区或子块中的每一个的预测模式。
帧间预测单元244可以包含运动估计(motion estimation，ME)单元(图2中未示出)和运动补偿(motion compensation，MC)单元(图2中未示出)。运动估计单元用于接收或获取图片图像块203(当前图片201的当前图片图像块203)和经解码图片231，或至少一个或多个先前经重构块，例如，一个或多个其它/不同先前经解码图片231的经重构块，来进行运动估计。例如，视频序列可以包括当前图片和先前经解码图片31，或换句话说，当前图片和先前经解码图片31可以是形成视频序列的图片序列的一部分，或者形成该图片序列。
例如，编码器20可以用于从多个其它图片中的同一或不同图片的多个参考块中选择参考块，并向运动估计单元(图2中未示出)提供参考图片和/或提供参考块的位置(X、Y坐标)与当前块的位置之间的偏移(空间偏移)作为帧间预测参数。该偏移也称为运动向量(motion vector，MV)。
运动补偿单元用于获取帧间预测参数，并基于或使用帧间预测参数执行帧间预测来获取帧间预测块245。由运动补偿单元(图2中未示出)执行的运动补偿可以包含基于通过运动估计(可能执行对子像素精确度的内插)确定的运动/块向量取出或生成预测块。内插滤波可从已知像素样本产生额外像素样本，从而潜在地增加可用于编码图片块的候选预测块的数目。一旦接收到用于当前图片块的PU的运动向量，运动补偿单元246可以在一个参考图片列表中定位运动向量指向的预测块。运动补偿单元246还可以生成与块和视频条带相关联的语法元素，以供解码器30在解码视频条带的图片块时使用。
具体的，上述帧间预测单元244可向熵编码单元270传输语法元素，所述语法元素包括帧间预测参数(比如遍历多个帧间预测模式后选择用于当前块预测的帧间预测模式的指示信息)。可能应用场景中，如果帧间预测模式只有一种，那么也可以不在语法元素中携带帧间预测参数，此时解码端30可直接使用默认的预测模式进行解码。可以理解的，帧间预测单元244可以用于执行帧间预测技术的任意组合。
帧内预测单元254用于获取，例如接收同一图片的图片块203(当前图片块)和一个或多个先前经重构块，例如经重构相相邻块，以进行帧内估计。例如，编码器20可以用于从多个(预定)帧内预测模式中选择帧内预测模式。
编码器20的实施例可以用于基于优化标准选择帧内预测模式，例如基于最小残差(例如，提供最类似于当前图片块203的预测块255的帧内预测模式)或最小码率失真。
帧内预测单元254进一步用于基于如所选择的帧内预测模式的帧内预测参数确定帧内预测块255。在任何情况下，在选择用于块的帧内预测模式之后，帧内预测单元254还用于向熵编码单元270提供帧内预测参数，即提供指示所选择的用于块的帧内预测模式的信息。在一个实例中，帧内预测单元254可以用于执行帧内预测技术的任意组合。
具体的，上述帧内预测单元254可向熵编码单元270传输语法元素，所述语法元素包括帧内预测参数(比如遍历多个帧内预测模式后选择用于当前块预测的帧内预测模式的指示信息)。可能应用场景中，如果帧内预测模式只有一种，那么也可以不在语法元素中携带帧内预测参数，此时解码端30可直接使用默认的预测模式进行解码。
熵编码单元270用于将熵编码算法或方案(例如，可变长度编码(variable length coding，VLC)方案、上下文自适应VLC(context adaptive VLC，CAVLC)方案、算术编码方案、上下文自适应二进制算术编码(context adaptive binary arithmetic coding，CABAC)、基于语法的上下文自适应二进制算术编码(syntax-based context-adaptive binary arithmetic coding，SBAC)、概率区间分割熵(probability interval partitioning entropy，PIPE)编码或其它熵编码方法或技术)应用于经量化残差系数209、帧间预测参数、帧内预测参数和/或环路滤波器参数中的单个或所有上(或不应用)，以获取可以通过输出272以例如经编码比特流21的形式输出的经编码图片数据21。可以将经编码比特流传输到视频解码器30，或将其存档稍后由视频解码器30传输或检索。熵编码单元270还可用于熵编码正被编码的当前视频条带的其它语法元素。
视频编码器20的其它结构变型可用于编码视频流。例如，基于非变换的编码器20可以在没有针对某些块或帧的变换处理单元206的情况下直接量化残差信号。在另一实施方式中，编码器20可具有组合成单个单元的量化单元208和逆量化单元210。
具体的，在本申请实施例中，编码器20可用于实现后文实施例中描述的编码方法。
应当理解的是，视频编码器20的其它的结构变化可用于编码视频流。例如，对于某些图像块或者图像帧，视频编码器20可以直接地量化残差信号而不需要经变换处理单元206处理，相应地也不需要经逆变换处理单元212处理；或者，对于某些图像块或者图像帧，视频编码器20没有产生残差数据，相应地不需要经变换处理单元206、量化单元208、逆量化单元210和逆变换处理单元212处理；或者，视频编码器20可以将经重构图像块作为参考块直接地进行存储而不需要经滤波器220处理；或者，视频编码器20中量化单元208和逆量化单元210可以合并在一起。环路滤波器220是可选的，以及针对无损压缩编码的情况下，变换处理单元206、量化单元208、逆量化单元210和逆变换处理单元212是可选的。应当理解的是，根据不同的应用场景，帧间预测单元244和帧内预测单元254可以是被选择性的启用。
参见图3，图3示出用于实现本申请实施例的解码器30的实例的示意性/概念性框图。视频解码器30用于接收例如由编码器20编码的经编码图片数据(例如，经编码比特流)21，以获取经解码图片231。在解码过程期间，视频解码器30从视频编码器20接收视频数据，例如表示经编码视频条带的图片块的经编码视频比特流及相关联的语法元素。
在图3的实例中，解码器30包括熵解码单元304、逆量化单元310、逆变换处理单元312、重构单元314(例如求和器314)、缓冲器316、环路滤波器320、经解码图片缓冲器330以及预测处理单元360。预测处理单元360可以包含帧间预测单元344、帧内预测单元354和模式选择单元362。在一些实例中，视频解码器30可执行大体上与参照图2的视频编码器20描述的编码遍次互逆的解码遍次。
熵解码单元304用于对经编码图片数据21执行熵解码，以获取例如经量化系数309和/或经解码的编码参数(图3中未示出)，例如，帧间预测、帧内预测参数、环路滤波器参数和/或其它语法元素中(经解码)的任意一个或全部。熵解码单元304进一步用于将帧间预测参数、帧内预测参数和/或其它语法元素转发至预测处理单元360。视频解码器30可接收视频条带层级和/或视频块层级的语法元素。
逆量化单元310功能上可与逆量化单元110相同，逆变换处理单元312功能上可与逆变换处理单元212相同，重构单元314功能上可与重构单元214相同，缓冲器316功能上可与缓冲器216相同，环路滤波器320功能上可与环路滤波器220相同，经解码图片缓冲器330功能上可与经解码图片缓冲器230相同。
预测处理单元360可以包括帧间预测单元344和帧内预测单元354，其中帧间预测单元344功能上可以类似于帧间预测单元244，帧内预测单元354功能上可以类似于帧内预测单元254。预测处理单元360通常用于执行块预测和/或从经编码数据21获取预测块365，以及从例如熵解码单元304(显式地或隐式地)接收或获取预测相关参数和/或关于所选择的预测模式的信息。
当视频条带经编码为经帧内编码(I)条带时，预测处理单元360的帧内预测单元354用于基于信号表示的帧内预测模式及来自当前帧或图片的先前经解码块的数据来产生用于当前视频条带的图片块的预测块365。当视频帧经编码为经帧间编码(即B或P)条带时，预测处理单元360的帧间预测单元344(例如，运动补偿单元)用于基于运动向量及从熵解码单元304接收的其它语法元素生成用于当前视频条带的视频块的预测块365。对于帧间预测，可从一个参考图片列表内的一个参考图片中产生预测块。视频解码器30可基于存储于DPB 330中的参考图片，使用默认建构技术来建构参考帧列表：列表0和列表1。
预测处理单元360用于通过解析运动向量和其它语法元素，确定用于当前视频条带的视频块的预测块，并使用预测块产生用于正经解码的当前视频块的预测块。在本申请的一实例中，预测处理单元360使用接收到的一些语法元素确定用于编码视频条带的视频块的预测模式(例如，帧内或帧间预测)、帧间预测条带类型(例如，B条带、P条带或GPB条带)、用于条带的参考图片列表中的一个或多个的建构信息、用于条带的每个经帧间编码视频块的运动向量、条带的每个经帧间编码视频块的帧间预测状态以及其它信息，以解码当前视频条带的视频块。在本公开的另一实例中，视频解码器30从比特流接收的语法元素包含接收自适应参数集(adaptive parameter set，APS)、序列参数集(sequence parameter set，SPS)、图片参数集(picture parameter set，PPS)或条带标头中的一个或多个中的语法元素。
逆量化单元310可用于逆量化(即，反量化)在比特流中提供且由熵解码单元304解码的经量化变换系数。逆量化过程可包含使用由视频编码器20针对视频条带中的每一视频块所计算的量化参数来确定应该应用的量化程度并同样确定应该应用的逆量化程度。
逆变换处理单元312用于将逆变换(例如，逆DCT、逆整数变换或概念上类似的逆变换过程)应用于变换系数，以便在像素域中产生残差块。
重构单元314(例如，求和器314)用于将逆变换块313(即经重构残差块313) 添加到预测块365，以在样本域中获取经重构块315，例如通过将经重构残差块313的样本值与预测块365的样本值相加。
环路滤波器单元320(在编码循环期间或在编码循环之后)用于对经重构块315进行滤波以获取经滤波块321，从而顺利进行像素转变或提高视频质量。在一个实例中，环路滤波器单元320可以用于执行下文描述的滤波技术的任意组合。环路滤波器单元320旨在表示一个或多个环路滤波器，例如去块滤波器、样本自适应偏移(sample-adaptive offset，SAO)滤波器或其它滤波器，例如双边滤波器、自适应环路滤波器(adaptive loop filter，ALF)，或锐化或平滑滤波器，或协同滤波器。尽管环路滤波器单元320在图3中示出为环内滤波器，但在其它配置中，环路滤波器单元320可实施为环后滤波器。
随后将给定帧或图片中的经解码视频块321存储在存储用于后续运动补偿的参考图片的经解码图片缓冲器330中。
解码器30用于例如，藉由输出332输出经解码图片31，以向用户呈现或供用户查看。
视频解码器30的其它变型可用于对压缩的比特流进行解码。例如，解码器30可以在没有环路滤波器单元320的情况下生成输出视频流。例如，基于非变换的解码器30可以在没有针对某些块或帧的逆变换处理单元312的情况下直接逆量化残差信号。在另一实施方式中，视频解码器30可以具有组合成单个单元的逆量化单元310和逆变换处理单元312。
具体的，在本申请实施例中，解码器30用于实现后文实施例中描述的解码方法。
应理解的是，块划分操作可以由预测处理单元360执行，或者由独立的单元(图中未示出)执行。预测处理单元360可以用于将图像块203分割成较小的块分区或子块，例如，通过迭代使用四叉树(quad-tree，QT)分割、二进制树(binary-tree，BT)分割或三叉树(triple-tree，TT)或者扩展四叉树(EQT,Extended Quad-Tree)分割，或其任何组合，划分的方式可以基于预设的规则确定或者基于解析的用于指示划分方式的语法元素确定，以及用于例如为块分区或子块中的每一个执行预测，其中模式选择包括选择分割的图像块203的树结构和选择应用于块分区或子块中的每一个的预测模式。
应当理解的是，视频解码器30的其它结构变化可用于解码经编码视频位流。例如，视频解码器30可以不经滤波器320处理而生成输出视频流；或者，对于某些图像块或者图像帧，视频解码器30的熵解码单元304没有解码出经量化的系数，相应地不需要经逆量化单元310和逆变换处理单元312处理。环路滤波器320是可选的；以及针对无损压缩的情况下，逆量化单元310和逆变换处理单元312是可选的。应当理解的是，根据不同的应用场景，帧间预测单元和帧内预测单元可以是被选择性的启用。
应当理解的是，本申请的编码器20和解码器30中，针对某个环节的处理结果可以经过进一步处理后，输出到下一个环节，例如，在插值滤波、运动矢量推导或环路滤波等环节之后，对相应环节的处理结果进一步进行Clip或移位shift等操作。
例如，按照相邻仿射编码块的运动矢量推导得到的当前图像块的控制点的运动矢量，或者推导得到的当前图像块的子块的运动矢量，可以经过进一步处理，本申请对 此不做限定。例如，对运动矢量的取值范围进行约束，使其在一定的位宽内。假设允许的运动矢量的位宽为bitDepth，则运动矢量的范围为-2^(bitDepth-1)～2^(bitDepth-1)-1，其中“^”符号表示幂次方。如bitDepth为16，则取值范围为-32768～32767。如bitDepth为18，则取值范围为-131072～131071。又例如，对运动矢量(例如一个8x8图像块内的四个4x4子块的运动矢量MV)的取值进行约束，使得所述四个4x4子块MV的整数部分之间的最大差值不超过N个像素，例如不超过一个像素。
可以通过以下两种方式进行约束，使其在一定的位宽内：
方式1，将运动矢量溢出的高位去除：
ux＝(vx+2 bitDepth)％2 bitDepth
vx＝(ux>＝2 bitDepth-1)？(ux-2 bitDepth):ux
uy＝(vy+2 bitDepth)％2 bitDepth
vy＝(uy>＝2 bitDepth-1)？(uy-2 bitDepth):uy
其中，vx为图像块或所述图像块的子块的运动矢量的水平分量，vy为图像块或所述图像块的子块的运动矢量的垂直分量，ux和uy为中间值；bitDepth表示位宽。
例如vx的值为-32769，通过以上公式得到的为32767。因为在计算机中，数值是以二进制的补码形式存储的，-32769的二进制补码为1,0111,1111,1111,1111(17位)，计算机对于溢出的处理为丢弃高位，则vx的值为0111,1111,1111,1111，则为32767，与通过公式处理得到的结果一致。
方法2，将运动矢量进行Clipping，如以下公式所示：
vx＝Clip3(-2bitDepth-1,2bitDepth-1-1,vx)
vy＝Clip3(-2bitDepth-1,2bitDepth-1-1,vy)
其中vx为图像块或所述图像块的子块的运动矢量的水平分量，vy为图像块或所述图像块的子块的运动矢量的垂直分量；其中，x、y和z分别对应MV钳位过程Clip3的三个输入值，所述Clip3的定义为，表示将z的值钳位到区间[x,y]之间：
Figure PCTCN2020070976-appb-000001
参见图4，图4是本申请实施例提供的视频译码设备400(例如视频编码设备400或视频解码设备400)的结构示意图。视频译码设备400适于实施本文所描述的实施例。在一个实施例中，视频译码设备400可以是视频解码器(例如图1A的解码器30)或视频编码器(例如图1A的编码器20)。在另一个实施例中，视频译码设备400可以是上述图1A的解码器30或图1A的编码器20中的一个或多个组件。
视频译码设备400包括：用于接收数据的入口端口410和接收单元(Rx)420， 用于处理数据的处理器、逻辑单元或中央处理器(CPU)430，用于传输数据的发射器单元(Tx)440和出口端口450，以及，用于存储数据的存储器460。视频译码设备400还可以包括与入口端口410、接收器单元420、发射器单元440和出口端口450耦合的光电转换组件和电光(EO)组件，用于光信号或电信号的出口或入口。
处理器430通过硬件和软件实现。处理器430可以实现为一个或多个CPU芯片、核(例如，多核处理器)、FPGA、ASIC和DSP。处理器430与入口端口410、接收器单元420、发射器单元440、出口端口450和存储器460通信。处理器430包括译码模块470(例如编码模块470或解码模块470)。编码/解码模块470实现本文中所公开的实施例，以实现本申请实施例所提供的色度块预测方法。例如，编码/解码模块470实现、处理或提供各种编码操作。因此，通过编码/解码模块470为视频译码设备400的功能提供了实质性的改进，并影响了视频译码设备400到不同状态的转换。或者，以存储在存储器460中并由处理器430执行的指令来实现编码/解码模块470。
存储器460包括一个或多个磁盘、磁带机和固态硬盘，可以用作溢出数据存储设备，用于在选择性地执行这些程序时存储程序，并存储在程序执行过程中读取的指令和数据。存储器460可以是易失性和/或非易失性的，可以是只读存储器(ROM)、随机存取存储器(RAM)、随机存取存储器(ternary content-addressable memory，TCAM)和/或静态随机存取存储器(SRAM)。
参见图5，图5是根据一示例性实施例的可用作图1A中的源设备12和目的地设备14中的任一个或两个的装置500的简化框图。装置500可以实现本申请的技术。换言之，图5为本申请实施例的编码设备或解码设备(简称为译码设备500)的一种实现方式的示意性框图。其中，译码设备500可以包括处理器510、存储器530和总线系统550。其中，处理器和存储器通过总线系统相连，该存储器用于存储指令，该处理器用于执行该存储器存储的指令。译码设备的存储器存储程序代码，且处理器可以调用存储器中存储的程序代码执行本申请描述的各种视频编码或解码方法，尤其是各种新的解码的方法。为避免重复，这里不再详细描述。
在本申请实施例中，该处理器510可以是中央处理单元(Central Processing Unit，简称为“CPU”)，该处理器510还可以是其他通用处理器、数字信号处理器(DSP)、专用集成电路(ASIC)、现成可编程门阵列(FPGA)或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件等。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。
该存储器530可以包括只读存储器(ROM)设备或者随机存取存储器(RAM)设备。任何其他适宜类型的存储设备也可以用作存储器530。存储器530可以包括由处理器510使用总线550访问的代码和数据531。存储器530可以进一步包括操作系统533和应用程序535，该应用程序535包括允许处理器510执行本申请描述的视频编码或解码方法(尤其是本申请描述的解码方法)的至少一个程序。例如，应用程序535可以包括应用1至N，其进一步包括执行在本申请描述的视频编码或解码方法的视频编码或解码应用(简称视频译码应用)。
该总线系统550除包括数据总线之外，还可以包括电源总线、控制总线和状态信号总线等。但是为了清楚说明起见，在图中将各种总线都标为总线系统550。
可选的，译码设备500还可以包括一个或多个输出设备，诸如显示器570。在一个示例中，显示器570可以是触感显示器，其将显示器与可操作地感测触摸输入的触感单元合并。显示器570可以经由总线550连接到处理器510。
下面详细阐述本申请实施例的方案：
视频编码标准把一帧图像分割成互不重叠的编码树单元(CTU)，CTU的大小可设置为64×64(CTU的大小也可设置为其它值，如CTU大小增大为128×128或256×256等)。64×64的CTU包含由64列、每列64个像素的矩形像素点阵，每个像素包含亮度分量或/和色度分量。CTU：编码树单元(coding tree unit)，一幅图像由多个CTU构成，一个CTU通常对应于一个方形图像区域，包含这个图像区域中的亮度像素和色度像素(或者也可以只包含亮度像素，或者也可以只包含色度像素)；CTU中还包含语法元素，这些语法元素指示如何将CTU划分成至少一个编码单元(coding unit,CU)，以及解码每个编码单元得到重建图像的方法。
CU：编码单元，通常对应于一个A×B的矩形区域，包含A×B亮度像素和它对应的色度像素，A为矩形的宽，B为矩形的高，A和B可以相同也可以不同，A和B的取值通常为2的整数次幂，例如256、128、64、32、16、8、4。一个编码单元可通过解码处理解码得到一个A×B的矩形区域的重建图像，解码处理通常包括预测、反量化、反变换等处理，产生预测图像和残差，预测图像和残差叠加后得到重建图像。
四叉树(QT,Quad-Tree):一种树状结构，一个节点可划分为四个子节点。视频编码标准采用基于四叉树的CTU划分方式：CTU作为根节点，每个节点对应于一个方形的区域，即把这个方形区域划分成四个大小相同的方形区域(其长、宽各为划分前区域长、宽的一半)，每个区域对应于一个节点，如图6(a)所示。一个节点可以不再划分(此时它对应的区域为一个CU)，或者将这个节点按QT、BT、TT或EQT的方式继续划分成下一层级的节点。
二叉树(BT,Binary Tree)：一种树状结构，一个节点可划分成两个子节点。划分成两个节点的方式有两种：1)水平二分，将节点对应的区域划分成上、下两个相同大小的区域，每个区域对应于一个节点，如图6(b)所示；或者2)竖直二分，将节点对应的区域划分成左、右两个大小相同的区域，每个区域对应于一个节点，如图6(c)所示。采用二叉树的编解码方法中，一个二叉树结构上的节点可以不划分(此时它对应的区域为一个CU)，或者把此节点按BT、TT或EQT的方式继续划分成下一层级的节点。
三叉树(Ternary tree，简称TT)：一种树状结构，一个节点可划分成三个子节点。现有采用三叉树的编码方法中，一个三叉树结构上的节点可以不划分，或者把此节点划分成三个下一层级的节点。划分成三个节点的方式有两种：1)水平三分，将节点对应的区域划分成上、中、下三个区域，每个区域对应于一个节点，其中上、中、下三个区域的高分别为节点高的1/4、1/2、1/4，如图6(d)所示；或者2)竖直三分，将节点对应的区域划分成左、中、右三个区域，每个区域对应于一个节点，其中左、中、右三个区域的宽分别为节点高的1/4、1/2、1/4，如图6(e)所示。采用三叉树的编解码方法中，一个三叉树结构上的节点可以不划分(此时它对应的区域为一个CU)，或者把此节点按BT、TT或EQT的方式继续划分成下一层级的节点。
扩展四叉树(EQT,Extended Quad-Tree):一种工字划分结构，一个节点可划分成四个子节点。划分成三个节点的方式有两种：1)水平四分，将节点对应的区域划分成上、中、下三个区域，每个区域对应于一个节点，其中上、中左、中右、下三个区域的高分别为节点高的1/4、1/2、1/2、1/4，中左和中右宽度为节点高度的1/2、1/2，如图6(f)所示；或者2)竖直四分，将节点对应的区域划分成左、中上、中下、右三个区域，每个区域对应于一个节点，其中左、中、右三个区域的宽分别为节点高的1/4、1/2、1/2、1/4，中上和中下宽度为节点高度的1/2、1/2，如图6(g)所示。采用扩展四叉树的编码方法中，一个扩展四叉树结构上的节点可以不划分，或者把此节点按BT、TT或EQT的方式继续划分成下一层级的节点。
视频解码(video decoding)：将视频码流按照特定的语法规则和处理方法恢复成重建图像的处理过程。
视频编码(video encoding)：将图像序列压缩成码流的处理过程；
视频编码(video coding)：video encoding和video decoding的统称，中文译名和video encoding相同。
VTM：JVET组织开发的新式编解码器参考软件。
视频编码标准把一帧图像分割成互不重叠的编码树单元(CTU)，CTU的大小可设置为64×64(CTU的大小也可设置为其它值，如CTU大小增大为128×128或256×256等)。64×64的CTU包含由64列、每列64个像素的矩形像素点阵，每个像素包含亮度分量或/和色度分量。
使用基于四叉树(quad-tree，简称QT)的CTU划分方法，将CTU作为四叉树的根节点(root)，按照四叉树的划分方式，将CTU递归划分成若干个叶节点(leaf node)。一个节点对应于一个图像区域，节点如果不划分，则节点称为叶节点，它对应的图像区域形成一个CU；如果节点继续划分，则节点对应的图像区域划分成四个相同大小的区域(其长和宽各为被划分区域的一半)，每个区域对应一个节点，需要分别确定这些节点是否还会划分。一个节点是否划分由码流中这个节点对应的划分标志位split_cu_flag指示。根节点的四叉树层级(qtDepth)为0，子节点的四叉树层级为父节点的四叉树层级+1。为表述简洁，下文中节点的大小和形状即指节点对应的图像区域的大小和形状。
更具体的，对64×64的CTU节点(四叉树层级为0)，根据它对应的split_cu_flag，可选择不划分，成为1个64×64的CU，或者选择划分为4个32×32的节点(四叉树层级为1)。这四个32×32的节点中的每一个节点，又可以根据它对应的split_cu_flag，选择继续划分或者不划分；如果一个32×32的节点继续划分，则产生四个16×16的节点(四叉树层级为2)。以此类推，直到所有节点都不再划分，这样一个CTU就被划分成一组CU。CU的最小尺寸(size)在SPS中标识，例如8×8为最小CU。在上述递归划分过程中，如果一个节点的尺寸等于最小CU尺寸(minimum CU size)，这个节点默认为不再划分，同时也不需要在码流中包含它的划分标志位。
当解析到一个节点为叶节点后，此叶节点为一个CU，进一步解析CU对应的编码信息(包括CU的预测模式、变换系数等信息，例如coding_unit()语法结构体)，然后按照这些编码信息对CU进行预测、反量化、反变换、环路滤波等解码处理，产生这 个CU对应的重建图像。四叉树结构使得CTU能够根据图像局部特点划分成合适大小的一组CU，例如平滑区域划分成较大的CU，而纹理丰富区域划分为较小的CU。
一种CTU划分成一组CU的划分方式对应于一个编码树(coding tree)。CTU应当采用何种编码树则通常通过编码器的率失真优化(rate distortion optimization,RDO)技术来确定。编码器尝试多种CTU划分方式，每一种划分方式对应于一个率失真代价(RD cost)；编码器比较各种尝试过的划分方式的RD cost，找到RD cost最小的划分方式，作为该CTU最优的划分方式，用于该CTU的实际编码。编码器尝试的各种CTU划分方式均需要符合解码器规定的划分规则，这些才能够被解码器正确识别。
在屏幕内容视频中，同一幅图像中通常含有相同内容，比如含有数字或者图形的图像中，当前块可以在其周围找到相同的数字或者图形，如图7所示。因此如果当前块在编码时，如果能在周围搜索到可以参考的复制块，直接参考其重建像素，会大大提高编码压缩率。帧内块拷贝技术(Intra Block Copy，IBC)是一个在当前屏幕内容中寻找相同的块的帧内预测技术。例如，可使用表2所述中的语法元素pred_mode_ibc_flag来表示当前编码单元是否使用IBC预测模式。
在四叉树划分的基础上，可以增加二叉树(binary tree，简称BT)划分方式和扩展四叉树(Extended Quad-Tree，简称EQT)划分方式。
二叉树划分将一个节点划分成2个子节点，具体的两叉树划分方式有两种：
1)水平二分：将节点对应的区域划分成上、下两个相同大小的区域(即宽不变，高变为划分前区域的一半)，每个区域对应于一个节点；如图6(b)所示。
2)竖直二分：将节点对应的区域划分成左、右两个相同大小的区域(即高不变，宽变为划分前区域的一半)；如图6(c)所示。
扩展四叉树划分将一个节点划分成4个子节点，具体的扩展四叉树划分方式有两种：
1)水平四分，将节点对应的区域划分成上、中、下三个区域，每个区域对应于一个节点，其中上、中左、中右、下三个区域的高分别为节点高的1/4、1/2、1/2、1/4，中左和中右宽度为节点高度的1/2、1/2，如图6(f)所示；
2)竖直四分，将节点对应的区域划分成左、中上、中下、右三个区域，每个区域对应于一个节点，其中左、中、右三个区域的宽分别为节点高的1/4、1/2、1/2、1/4，中上和中下宽度为节点高度的1/2、1/2，如图6(g)所示。
QT级联BT/EQT的划分方式，即第一级编码树上的节点只能使用QT划分成子节点，第一级编码树的叶节点为第二级编码树的根节点；第二级编码树上的节点可使用BT或EQT划分方式中的一种划分为子节点；第二级编码树的叶节点为编码单元。需要注意的是，当叶节点为BT或EQT划分方式时，其叶节点只能使用BT或EQT划分方式，而不能使用QT的方式。
也可以在四叉树划分的基础上，增加了二叉树(binary tree，简称BT)划分方式和三叉树(ternary tree，简称TT)划分方式。
二叉树划分将一个节点划分成2个子节点，具体的两叉树划分方式有两种：
1)水平二分：将节点对应的区域划分成上、下两个相同大小的区域(即宽不变，高变为划分前区域的一半)，每个区域对应于一个节点；如图6(b)所示。
2)竖直二分：将节点对应的区域划分成左、右两个相同大小的区域(即高不变，宽变为划分前区域的一半)；如图6(c)所示。
三叉树划分将一个节点划分成2个子节点，具体的两叉树划分方式有两种：
水平三分：将节点对应的区域划分成上、中、下三个区域，每个区域对应于一个节点，其中上、中、下三个区域的高分别为节点高的1/4、1/2、1/4，如图6(d)所示；
竖直三分：将节点对应的区域划分成左、中、右三个区域，每个区域对应于一个节点，其中左、中、右三个区域的宽分别为节点高的1/4、1/2、1/4，如图6(e)所示
QT级联BT/TT的划分方式，简称为QT-BTT，即第一级编码树上的节点只能使用QT划分成子节点，第一级编码树的叶节点为第二级编码树的根节点；第二级编码树上的节点可使用水平二分、竖直二分、水平三分、竖直三分这四种划分方式中的一种划分为子节点；第二级编码树的叶节点为编码单元。
CU级的部分语法结构可以如表1所示，如果当前节点不再划分为子节点，则当前节点为编码单元，按照以下的语法结构解析编码单元的预测块。
其中，skip_flag为跳过模式的标志，值为1表示当前CU使用跳过模式，值为0表示当前CU不使用跳过模式。
merge_flag为直接模式标志，值为1表示当前CU使用融合模式；值为0表示不使用融合模式。
cu_pred_mode为编码单元预测模式标志，值为1表示当前预测单元使用帧内预测模式；值为0表示当前预测单元使用普通inter预测模式。
表1
Figure PCTCN2020070976-appb-000002
CU级的部分语法解析也可以如表2所示，表2仅为一种示例，其中与表1中的skip_flag含义相同，pred_mode_flag含义与表1中cu_pred_mode含义相同。
其中，cu_skip_flag为跳过模式的标志，值为1表示当前CU使用跳过模式，值为0表示当前CU不使用跳过模式。
general_merge_flag为融合模式标志，值为1表示当前CU使用融合模式；值为0 表示不使用融合模式。
pred_mode_flag为编码单元预测模式标志，值为1表示当前编码单元使用帧内预测模式；值为0表示当前编码单元使用普通inter预测模式。如果pred_mode_flag为1，CuPredMode[x0][y0]为CuPredMode[x0][y0]为MODE_INTRA；如果pred_mode_flag为0，CuPredMode[x0][y0]为MODE_INTER。
pred_mode_ibc_flag为1表示当前编码单元使用IBC预测模式，值为0表示当前编码单元不使用IBC预测模式。如果pred_mode_ibc_flag为1，则CuPredMode[x0][y0]为MODE_IBC。
其中，CuPredMode[x0][y0]表示当前编码单元的预测模式，(x0,y0)表示当前编码单元在当前图像中的位置。
表2
Figure PCTCN2020070976-appb-000003
一个8xM(或Mx8)大小的节点使用竖直二分(或水平二分)划分后会产生两个 4xM(或Mx4)大小的子节点；类似的，一个16xM(或Mx16)大小的节点使用垂直扩展四分(或水平扩展四分)划分后会产生四个4xM(或Mx4)大小的子节点和一个8xN(或Nx8)大小的子节点。类似的，一个16xM(或Mx16)大小的节点使用竖直三分(或水平三分)划分后会产生两个4xM(或Mx4)大小的子节点和一个8xM(或Nx8)大小的子节点。对于YUV4:2:0的数据格式，色度分量的分辨率为亮度分量的1/2，即一个4xM的节点包含了一个4xM的亮度块和两个2x(M/2)的色度块。对硬件解码器而言，小块(特别是2x2、2x4、2x8)的处理代价较高。然而，该划分方式会产生2x2、2x4等小块，不利于硬件解码器的实现。对硬件解码器而言，小块的处理复杂度较高，具体包括以下3个方面。
1)帧内预测问题：硬件设计中为了提高处理速度，帧内预测通常一次同时处理16个像素，而2x2、2x4、4x2等小块包含少于16个像素，降低了帧内预测的处理性能。
2)系数编码问题：HEVC中变换系数编码基于包含16个系数的系数组(coefficient group，CG)，而2x2、2x4、4x2的小块包含了4个或8个变换系数，这导致需要增加包含4个系数和8个系数的系数组来支持这些小块的系数编码，因此增加了实现复杂度。
3)帧间预测问题：小块的帧间预测对数据带宽要求较高，也会影响解码的处理速度。
当一个节点使用一种划分方式继续划分而产生的子节点中有一个子节点包含了边长为2的色度块，则将子节点包含的亮度块使用这种划分继续划分，而子节点的包含的色度块不再划分。通过这种方式，可以避免产生边长为2的色度块，降低解码器的最大吞吐率，利于解码器实现。同时提出根据亮度块预测模式确定色度块预测模式的方法，有效提升了编码效率。
本申请提供的图像预测方法可以应用于图8所示的视频编码器18或者视频解码器24。需要指出的是，下面几个实施例中的个别步骤仅在视频解码器24中执行，在下文中的对应位置会进行特别说明。
下面采用具体的实施例对本申请的图像预测方法进行详细说明，需要说明的是，下面几个具体实施例可以相互结合，对于相同或相似的内容，在不同的实施例中不再进行重复说明。
图9是本申请实施例提供的第一种图像预测方法的流程示意图。参见图9，本实施例提供的图像预测方法，包括如下步骤：
步骤101、获取当前节点的划分方式。
在本实施例中，首先解析当前节点的划分信息，划分信息用于指示对当前节点进行划分或者不划分。若划分信息指示对当前节点进行划分，获取当前节点的划分方式。其中，当前节点的划分方式包括四叉树划分、竖直二分、水平二分、竖直三分、水平三分的至少一种，当然还可以是其他的划分方式，对此本实施例不作具体限定。
当前节点的划分信息可以在码流中传输，通过解析码流中相应的语法元素可以解析当前节点的划分信息，并确定具体的划分方式。当前节点的划分方式也可以基于其 他预设的规则确定，本实施例不作具体限定。
在本实施例中，若解析到当前节点的划分信息用于指示对当前节点进行划分，划分信息中具体包括对当前节点包括的亮度块的划分方式，和/或，对当前节点包括的色度块的划分方式。其中，对当前节点包括的亮度块的划分方式和对当前节点包括的色度块的划分方式可以相同，也可以不同，对此本实施例不作具体限定。示例性的，划分信息用于指示对当前节点的亮度块和色度块均采用四叉树划分。或者，划分信息用于指示对当前节点的亮度块采用四叉树划分，对当前节点的色度块采用竖直二分。
步骤102、判断基于划分方式对当前节点进行划分是否会得到具有预设尺寸的图像块。
其中，预设尺寸的图像块可以为尺寸小于一个阈值的亮度块，该阈值可以是128、64或者32个亮度采样点数量，或者是32、16或者8个色度采样点数量。该当前节点的尺寸可以大于或者等于该阈值。
在确定基于划分方式对当前节点进行划分会得到具有预设尺寸的图像块的情况下，执行步骤103；在确定基于划分方式对当前节点进行划分不会得到具有预设尺寸的图像块的情况下，执行步骤104。
步骤103、对当前节点覆盖的所有编码块使用帧内预测，或者对当前节点覆盖的所有编码块使用帧间预测。
需要指出的是，本实施例中的当前节点可以理解为待处理或者待划分节点对应的图像区域或者图像块。当前节点覆盖的所有编码块可以理解为所有位于当前节点区域内的编码块。本实施例中的所有编码块包括对当前节点划分或者不划分的亮度编码块和色度编码块。其中，编码块也可以是编码单元(coding unit)。
可选的，使用帧内预测可以是使用通常的帧内预测模式(intra mode)进行预测，也可以是使用IBC(intra block copy)mode进行预测。
可选的，在当前节点所在的片的类型(slice type)是帧内(Intra)类型的情况下，对所述当前节点覆盖的所有编码块使用帧内预测，而不使用帧间预测。
在一种实现方式中，对当前节点覆盖的所有编码块使用帧内预测，可以包括：
按照划分方式对当前节点包括的亮度块进行划分，得到划分后的亮度块，对划分后的亮度块使用帧内预测；将当前节点包括的色度块作为色度编码块，对色度编码块使用帧内预测。
也就是说，如果确定当前节点的所有编码块均使用帧内预测，则对当前节点的亮度块按照亮度块的划分方式进行划分，得到N个亮度编码树节点；对当前节点的色度块不划分，得到一个色度编码块(简称色度CB)。
其中，N个亮度编码树节点可以限制为不再继续划分，或者不做此限制。如果亮度编码树节点继续划分，则解析其划分方式进行递归划分，当亮度编码树节点不再划分时，它对应一个亮度编码块(简称为亮度CB)。亮度CB使用帧内预测得到亮度CB对应的亮度预测块。
其中，色度CB使用帧内预测得到色度CB对应的色度预测块，色度预测块和色度CB的尺寸大小相同。
在一种实现方式中，对当前节点覆盖的所有编码块使用帧间预测，可以包括：
按照划分方式对当前节点包括的亮度块进行划分，得到划分后的亮度块；对划分后的亮度块使用帧间预测；将当前节点包括的色度块作为色度编码块，对色度编码块使用帧间预测。
也就是说，如果确定当前节点的所有编码块均使用帧间预测，则对当前节点的亮度块按照亮度块的划分方式进行划分，得到N个亮度编码树节点；对当前节点的色度块不划分，得到一个色度编码块(简称色度CB)。
本实施例中，在确定当前节点的所有编码块使用帧内预测时，或者，在确定当前节点的所有编码块使用帧间预测时，当前节点包括的亮度块按照当前节点的划分方式进行划分，当前节点的色度块不再划分。上述方法可以避免产生使用帧内预测的色度小块，从而解决了色度小块帧内预测的问题。
在一种实现方式中，对当前节点覆盖的所有编码块使用帧间预测，可以包括：
按照划分方式对当前节点包括的亮度块进行划分，得到划分后的亮度块，对划分后的亮度块使用帧间预测；按照划分方式对当前节点包括的色度块进行划分，得到划分后的色度块，对划分后的色度块使用帧间预测。
也就是说，如果确定当前节点的所有编码块均使用帧间预测，则对当前节点的亮度块按照亮度块的划分方式进行划分，得到N个亮度编码树节点；对当前节点的色度块按照色度块的划分方式进行划分，得到M个色度编码树节点。其中，N和M为正整数，N和M可以相同，也可以不同。对于N个亮度编码树节点和M个色度编码树节点可以限制为不再继续划分，或者不做此限制。不再继续划分时，N个亮度编码树节点对应当前节点的N个亮度CB，M个色度编码树节点对应当前节点的M个色度CB。N个亮度CB使用帧间预测得到对应的亮度预测块，M个色度CB使用帧间预测得到对应的色度预测块。
可选的，在对当前节点覆盖的所有编码块使用帧间预测的情况下，对当前节点覆盖的所有编码块使用帧间预测，可以包括：
获取当前节点的子节点的子划分方式，子节点包括亮度块和色度块；判断基于子划分方式对当前节点的子节点进行划分是否会得到具有第一预设尺寸的亮度块；在确定基于子划分方式对当前节点的子节点进行划分会得到具有第一预设尺寸的亮度块的情况下，对以当前节点的子节点采用子划分方式之外的划分方式进行划分，得到对应的编码块，并对对应的编码块使用帧间预测，或者，将当前节点的子节点作为编码块使用帧间预测。
也就是说，如果按照当前节点的子节点的子划分方式对子节点进行划分会产生具有第一预设尺寸(4x4)的亮度块，则该子节点的子划分方式不被允许，或者，该子节点不能继续划分，或者，采用子划分方式之外的划分方式对子节点进行划分。例如，如果当前节点的尺寸为8x8且使用水平二叉树(或者竖直二叉树)划分产生两个8x4(或两个4x8)的节点，8x4(或4x8)的节点继续划分会产生4x4的块，因此，此时 8x4(或4x8)的节点不能继续划分。
步骤104、采用当前节点的划分方式对当前节点进行划分，不限制当前节点覆盖的所有编码块的预测模式。
具体的，采用当前节点的亮度块的划分方式对当前节点的亮度块进行划分，采用当前节点的色度块的划分方式对当前节点的色度块进行划分。
需要指出的是，步骤104中不限制当前节点覆盖的所有编码块的预测模式可以理解为：当前节点覆盖的所有编码块可以不按照同一预测模式进行预测，即解析每一个编码块的预测模式，每一个编码块根据解析的预测模式进行预测。
可选的，在步骤103或者步骤104之后，还包括：
步骤105、解析当前节点覆盖的所有编码块的预测块和残差信息。
步骤106、解码各编码块，得到当前节点对应的图像块的重建信号。
需要说明的是，上述两个步骤可以应用于图8所示的视频解码器24。
其中，预测块包括：预测模式(指示帧内预测或非帧内预测模式)、帧内预测模式、帧间预测模式、运动信息等。运动信息可包括预测方向(前向、后向或双向)、参考帧索引(reference index)、运动矢量(motion vector)等信息。
残差信息包括：编码块标志位(coded block flag，cbf)、变换系数、变换类型(例如DCT-2,DST-7,DCT-8)等。变换类型可默认为DCT-2变换。
如果当前节点覆盖的所有编码块限制只能使用帧内预测，则当前节点划分得到的亮度CB的预测块解析包括将skip_flag、merge_flag、cu_pred_mode分别默认为0、0和1(即skip_flag、merge_flag、cu_pred_mode均不出现在码流中)，或者skip_flag、cu_pred_mode分别默认为0和1(即skip_flag、cu_pred_mode均不出现在码流中)将解析亮度CB的帧内预测模式信息；当前节点划分得到的色度CB的预测块解析包括解析色度CB的帧内预测模式。色度CB的帧内预测模式的解析方法可以是：1)从码流中解析语法元素得到；2)直接设定为色度帧内预测模式集合中的一种，例如线性模型模式、DM模式(chroma derived mode，DM)和IBC模式等中的一种。
如果当前节点覆盖的所有编码块限制只能使用帧间预测，则当前节点划分得到的CU的预测模式解析包括解析skip_flag或/和merge_flag，将cu_pred_mode默认为0，解析帧间预测块，如融合索引(merge index)、帧间预测方向(inter dir)，参考帧索引(reference index)、运动矢量预测值索引(motion vector predictor index)和运动矢量差分量(motion vector difference)。其中，skip_flag为跳过模式的标志，值为1表示当前CU使用跳过模式，值为0表示当前CU不使用跳过模式。merge_flag为融合模式标志，值为1表示当前CU使用融合模式；值为0表示不使用融合模式。cu_pred_mode为编码单元预测模式标志，值为1表示当前预测单元使用帧内预测；值为0表示当前预测单元使用普通帧间预测(在码流中标识帧间预测方向、参考帧索引、运动矢量预测值索引、运动矢量差分量等信息)。
可选的，如果当前节点覆盖的所有编码块限制只能使用帧间预测，则当前节点划分得到的亮度CB的预测块解析包括解析skip_flag或/和merge_flag，将cu_pred_mode 默认为0，解析帧间预测块，如融合索引(merge index)、帧间预测方向(inter dir)，参考帧索引(reference index)、运动矢量预测值索引(motion vector predictor index)和运动矢量差分量(motion vector difference)。由解析得到的帧间预测块，导出亮度CB中各4x4子块的运动信息。如果当前节点覆盖的所有编码块限制只能使用帧间预测，则当前节点划分得到的色度CB的预测块无需解析，将色度CB划分为2x2色度子块(该划分方式可以为划分方式S)，各2x2色度子块的运动信息为各2x2色度子块对应的4x4亮度区域的运动信息。通过上述划分方式，将不会产生使用帧内预测的色度小块，也不会产生小于16个像素的变换块，因此解决上述帧内预测问题和系数编码问题。
可选的，如果当前节点覆盖的所有编码块限制只能使用帧间预测，则当前节点划分得到的色度CB的预测块无需解析，色度预测块与色度编码块大小相同，色度CB的运动信息为色度CB对应的亮度区域中某个预设位置的运动信息(如亮度区域的中心、右下角或左上角等)。通过上述划分方式，将不会产生使用帧内预测的色度小块，也不会产生小块变换块，也不会产生使用帧间预测的色度小块。
需要说明的是，本实施例中帧内预测模式为使用编码块所在图像的空域参考像素产生编码块的预测值的预测模式，如直流模式(direct current mode,DC mode)，平面模式(Planar mode)，角度模式(angular mode)，还可能包含模版匹配模式(template matching mode)，IBC模式。帧间预测模式为使用编码块的参考图像中的时域参考像素产生编码块的预测值的预测模式，如跳过模式(Skip mode)，融合模式(Merge mode)，AMVP(advanced motion vector prediction)模式或称普通Inter模式等。
由各编码块的预测块对各编码块执行帧间预测或帧内预测，得到各编码块的帧间预测图像或帧内预测图像。再根据各编码块的残差信息，将变换系数经过反量化和反变换处理得到残差图像，并叠加到对应区域的预测图像上，产生重建图像。
可选的，在一种可能的实现方式中，具有预设尺寸的图像块包括具有第一预设尺寸的亮度块，对应的，步骤102包括：
判断基于对当前节点的亮度块的划分方式对当前节点进行划分，是否会得到具有第一预设尺寸的亮度块。其中，第一预设尺寸的亮度块是指像素尺寸为4×4的亮度块。
在基于对当前节点的亮度块的划分方式对当前节点的亮度块进行划分会得到具有第一预设尺寸的亮度块的情况下，对应的，步骤103包括：对当前节点覆盖的所有编码块使用帧内预测。
在基于对当前节点的亮度块的划分方式对当前节点的亮度块进行划分不会得到具有第一预设尺寸的亮度块的情况下，对应的，步骤104包括：采用当前节点的亮度块的划分方式对当前节点的亮度块进行划分，采用当前节点的色度块的划分方式对当前节点的色度块进行划分，不限制当前节点覆盖的所有编码块的预测模式。
可选的，在另一种可能的实现方式中，具有预设尺寸的图像块包括具有第二预设尺寸的色度块，对应的，步骤102包括：
判断基于对当前节点的色度块的划分方式对当前节点进行划分，是否会得到具有第二预设尺寸的色度块。其中，第二预设尺寸的色度块是指像素尺寸为2×2、2×4、或者4×2的色度块。
在基于对当前节点的色度块的划分方式对当前节点的色度块进行划分会得到具有第二预设尺寸的色度块的情况下，对应的，步骤103包括：对当前节点覆盖的所有编码块使用帧内预测，或者对当前节点覆盖的所有编码块使用帧间预测。
在基于对当前节点的色度块的划分方式对当前节点的色度块进行划分不会得到具有第二预设尺寸的色度块的情况下，对应的，步骤104包括：采用当前节点的色度块的划分方式对当前节点的色度块进行划分，采用当前节点的亮度块的划分方式对当前节点的亮度块进行划分，不限制当前节点覆盖的所有编码块的预测模式。本实施例提供的图像预测方法，通过获取当前节点的划分方式，判断基于当前节点的划分方式对当前节点进行划分是否会得到具有预设尺寸的图像块，其中图像块包括亮度块或色度块。在基于当前节点的划分方式对当前节点进行划分会得到具有预设尺寸的图像块的情况下，对当前节点覆盖的所有编码块使用帧内预测，或者对当前节点覆盖的所有编码块使用帧间预测。上述方法对当前节点的所有编码块均使用帧内或者均使用帧间预测，可以实现对当前节点的所有编码块的并行处理，提高图像预测的处理性能，从而提升编解码的处理速度。
在图9所示实施例的基础上，下述实施例提供的图像预测方法对基于当前节点的亮度块的划分方式对当前节点进行划分是否会得到具有第一预设尺寸的亮度块的判断过程进行详细说明，具体公开了具有第一预设尺寸的亮度块的判断集合。
图10是本申请实施例提供的第二种图像预测方法的流程示意图。如图10所示，本实施例提供的图像预测方法包括：
步骤201、获取当前节点的划分方式。
具体的，解析当前节点的划分信息，若划分信息指示对当前节点的亮度块进行划分，则进一步确定当前节点的亮度块的划分方式。其中，亮度块的划分方式包括四叉树划分、竖直二分、水平二分、竖直三分、水平三分的至少一种，当然还可以是其他的划分方式，对此本实施例不作具体限定。
步骤202、根据当前节点的尺寸和划分方式，确定基于划分方式对当前节点进行划分是否会得到具有第一预设尺寸的亮度块。
其中，第一预设尺寸的亮度块可以为像素尺寸为4×4，或8×8的亮度块。
在确定基于划分方式对当前节点进行划分会得到具有第一预设尺寸的亮度块的情况下，执行步骤203；在确定基于划分方式对当前节点进行划分不会得到具有第一预设尺寸的亮度块的情况下，执行步骤204。
具体的，根据当前节点的尺寸和当前节点的亮度块的划分方式，确定基于亮度块的划分方式对当前节点进行划分是否会得到具有第一预设尺寸的亮度块。
在实施例中，当前节点的尺寸可以理解为当前节点对应的图像块的像素尺寸。当前节点的尺寸可以根据当前节点对应的图像块的宽和高确定，也可以根据当前节点对 应的图像块的面积确定，还可以根据当前节点对应的图像块的亮度像素个数确定。例如，当前节点包括128个亮度像素点可以描述为当前节点的面积为128，还可以描述为当前节点的宽和高的乘积为128。
根据当前节点的尺寸和当前节点的亮度块的划分方式，确定基于亮度块的划分方式对当前节点进行划分会得到第一预设尺寸的亮度块，包括以下第一集合中的一个或者多个。
1)当前节点包含M1个像素且当前节点的划分方式为四叉树划分，例如M1为64；
2)当前节点包含M2个像素且当前节点的划分方式为三叉树划分，例如M2为64；
3)当前节点包含M3个像素且当前节点的划分方式为二叉树划分，例如M3为32；
4)当前节点包含64个亮度像素且当前节点使用三叉树划分(竖直三分或者水平三)或者四叉树划分，或者当前节点包含32个亮度像素且使用二叉树划分(竖直二分或水平二分)；
5)当前节点的宽等于第二阈值的4倍、高等于第二阈值且当前节点的划分方式为竖直三叉树划分；
6)当前节点的宽等于第二阈值、高等于第二阈值的4倍且当前节点的划分方式为水平三叉树划分；
7)当前节点的宽等于第二阈值的2倍、高等于第二阈值且当前节点的划分方式为竖直二分；
8)当前节点的高等于第二阈值的2倍、宽等于第二阈值且当前节点的划分方式为水平二分；
9)当前节点的宽或/和高为第二阈值的2倍且当前节点的划分方式为四叉树划分。
上述的第一集合中，当前节点的宽为当前节点对应亮度块的宽，当前节点的高为当前节点对应亮度块的高。在具体的实现方式中，例如第二阈值可以为4。
上述的第一集合适用于视频数据格式为YUV4:2:0或YUV4:2:2。
可选的，在该第一预设尺寸的亮度块为像素尺寸为4×4的情况下，根据所述当前节点的尺寸和所述划分方式，确定基于所述划分方式对当前节点进行划分是否会得到具有第一预设尺寸的亮度块，可以包括：
1)当前节点的亮度块的采样点数量为64，且该划分方式为四叉树划分；或者，
2)当前节点的亮度块的采样点数量为64，且该划分方式为三叉树划分；或者，
3)当前节点的亮度块的采样点数量为32，且该划分方式为二叉树划分。
其中，当前节点的亮度块的采样点数量即当前节点对应的图像块的亮度像素个数(像素尺寸)。
步骤203、对当前节点覆盖的所有编码块使用帧内预测。
作为一种步骤203的替代方式，可以是只对具有具有第一预设尺寸的亮度块的编码块进行帧内预测，而不限制当前节点覆盖的其他编码块的预测模式。
对当前节点覆盖的所有编码块使用帧内预测，可以包括：
按照划分方式对当前节点包括的亮度块进行划分，得到划分后的亮度块，对划分 后的亮度块使用帧内预测；将当前节点包括的色度块作为色度编码块，对色度编码块使用帧内预测。
也就是说，如果确定当前节点的所有编码块均使用帧内预测，则对当前节点的亮度块按照亮度块的划分方式进行划分，得到N个亮度编码树节点；对当前节点的色度块不划分，得到一个色度编码块(简称色度CB)。
其中，N个亮度编码树节点可以限制为不再继续划分，或者不做此限制。如果亮度编码树节点继续划分，则解析其划分方式进行递归划分，当亮度编码树节点不再划分时，它对应一个亮度编码块(简称为亮度CB)。亮度CB使用帧内预测得到亮度CB对应的亮度预测块。
其中，色度CB使用帧内预测得到色度CB对应的色度预测块，色度预测块和色度CB的尺寸大小相同。
可选的，对当前节点覆盖的所有编码块使用帧内预测，可以包括：
将当前节点包括的亮度块作为亮度编码块，对亮度编码块使用帧内预测；将当前节点包括的色度块作为色度编码块，对色度编码块使用帧内预测。也就是说，对当前节点的亮度块和色度块可以都不划分。
步骤204、采用当前节点的划分方式对当前节点进行划分，不限制当前节点覆盖的所有编码块的预测模式。
本实施例的步骤204同图9所示实施例的步骤104，具体参见上述实施例，此处不再赘述。
可选的，在步骤203或者步骤204之后，还包括：
步骤205、解析当前节点覆盖的所有编码块的预测块和残差信息。
步骤206、解码各编码块，得到当前节点对应的图像块的重建信号。
本实施例中步骤205和步骤206同图9所示实施例的步骤105和步骤106，具体参见上述实施例，此处不再赘述。
本实施例提供的图像预测方法，通过获取当前节点的划分方式，根据当前节点的尺寸和亮度块的划分方式，确定基于亮度块的划分方式对当前节点进行划分是否会得到第一预设尺寸的亮度块，在确定基于亮度块的划分方式对当前节点进行划分会得到第一预设尺寸的亮度块的情况下，对当前节点覆盖的所有编码块均使用帧内预测。上述方法对当前节点的所有编码块均使用帧内预测，可以实现对当前节点的所有编码块的并行处理，提高图像预测的处理性能，从而提升编解码的处理速度。
图11是本申请实施例提供的第三种图像预测方法的流程示意图。在图10所示实施例的基础上，如图11所示，需要说明的是，图11所示的方案可以是在视频数据格式为YUV4:2:0或YUV4:2:2的情况下的方案，也可以是仅在视频数据格式为YUV4:2:0的情况下的方案。在确定基于划分方式对当前节点进行划分不会得到具有第一预设尺寸的亮度块的情况下，步骤204，可以包括：
步骤2041、判断基于划分方式对当前节点进行划分是否会得到具有第二预设尺寸的色度块。
在确定基于划分方式对当前节点进行划分会得到具有第二预设尺寸的色度块的情况下，执行步骤2042；在确定基于划分方式对当前节点进行划分不会得到具有第二预设尺寸的色度块的情况下，执行步骤2043。
具体的，步骤2041，包括：根据当前节点的尺寸和色度块的划分方式，确定基于色度块的划分方式对当前节点进行划分是否会得到具有第二预设尺寸的色度块。其中，第二预设尺寸的色度块可以为像素尺寸为2×2、2×4、或者4×2的色度块。
根据当前节点的尺寸和色度块的划分方式，确定基于色度块的划分方式对当前节点进行划分会得到具有第二预设尺寸的色度块，包括以下第二集合中的一个或者多个。
当视频数据格式为YUV 4:2:2时，第二集合包括：
1)当前节点的至少一个子节点的色度块的尺寸为2x2、2x4、或4x2；
2)当前节点的至少一个子节点的色度块的宽或高为2；
3)当前节点包含64个亮度像素且当前节点的划分方式为三叉树划分或四叉树划分；
4)当前节点包含32个亮度像素且当前节点的划分方式为二叉树划分或三叉树划分；
5)当前节点的面积(或宽和高的乘积)为S，S/2<th1，且当前节点的划分方式为竖直二分或者水平二分；或者当前节点的面积(或宽和高的乘积)为S，S/4<th1，且当前节点的划分方式为竖直三分、水平三分、或者四叉树划分。其中，阈值th1为32。
当视频数据格式为YUV 4:2:0时，第二集合包括：
1)如果当前节点的至少一个子节点的色度块的尺寸为2x2、2x4、或4x2；
2)如果当前节点的至少一个子节点的色度块的宽或高为2；
3)如果当前节点包含128个亮度像素且当前节点使用三叉树划分，或者，如果当前节点包含64个亮度像素且当前节点使用二叉树划分或者四叉树划分或者三叉树划分；
4)如果当前节点包含256个亮度像素且节点使用三叉树划分或者四叉树划分，或者如果当前节点包含128个亮度像素且节点使用二叉树划分；
5)如果当前节点包含N1个亮度像素且当前节点使用三叉树划分，N1为64、128或者256。
6)如果当前节点包含N2个亮度像素且当前节点使用四叉树划分，N2为64或者256。
7)如果当前节点包含N3个亮度像素且当前节点使用二叉树划分，N3为64、128或者256。
8)当前节点的面积(或宽和高的乘积)为S，S/2<th1，且当前节点的划分方式为竖直二分或者水平二分；或者当前节点的面积(或宽和高的乘积)为S，S/4<th1，且当前节点的划分方式为竖直三分、水平三分、或者四叉树划分。其中，阈值th1为 64。
可选的，具有第一预设尺寸的亮度块可以为4×4的亮度块，在第一预设尺寸的亮度块是4×4的亮度块的情况下，第二预设尺寸的色度块可以为像素尺寸为2×4、或者4×2的色度块，而不包括像素尺寸为2×2的色度块。
可选的，具有第一预设尺寸的亮度块可以为4×4的亮度块，在第一预设尺寸的亮度块是4×4的亮度块的情况下，第二预设尺寸的色度块可以为像素尺寸为4×8、或者8×4的亮度块，而不包括像素尺寸为4×4的亮度块。
可选的，在第二预设尺寸的色度块为像素尺寸为2×4、或者4×2的色度块，或者像素尺寸为4×8、或者8×4的亮度块的情况下，判断基于划分方式对当前节点进行划分是否会得到第二预设尺寸的色度块，可以包括：
1)当前节点的亮度块的采样点数量为64，且该划分方式为二叉树划分；或者，
2)当前节点的亮度块的采样点数量为128，且该划分方式为三叉树划分。
步骤2042、对当前节点覆盖的所有编码块使用帧内预测，或者对当前节点覆盖的所有编码块使用帧间预测。
对当前节点覆盖的所有编码块均使用帧内预测或均使用帧间预测，可以通过以下方法确定。
方法一：解析当前节点的预测模式状态标识，在预测模式状态标识的值为第一值时，对当前节点覆盖的所有编码块使用帧间预测；或者，在预测模式状态标识的值为第二值时，对当前节点覆盖的所有编码块使用帧内预测。
该方法实际上是根据语法表中的标志位确定对当前节点覆盖的所有编码块的预测模式。具体的，从码流中解析预测模式状态标识cons_pred_mode_flag。其中，cons_pred_mode_flag的第一值设置为0，表示对当前节点进行划分或者不划分得到的所有编码块均使用帧间预测，cons_pred_mode_flag的第二值设置为1，表示对当前节点进行划分或者不划分得到的所有编码块均使用帧内预测。可选的，cons_pred_mode_flag的第一值设置为1，表示对当前节点进行划分或者不划分得到的所有编码块均使用帧间预测，cons_pred_mode_flag的第二值设置为0，表示对当前节点进行划分或者不划分得到的所有编码块均使用帧内预测。cons_pred_mode_flag所表述的含义还可以使用其他的标识(例如mode_cons_flag)来表示，对此本实施例不做限定。
cons_pred_mode_flag可以为块划分过程中需要解析的语法元素，当解析该语法元素时，则当前节点覆盖区域的编码单元的编码单元预测模式标志cu_pred_mode可以不再解析，其值为与cons_pred_mode_flag的值对应的默认值。
语法元素cons_pred_mode_flag的语义描述如下：cons_pred_mode_flag为0，表示对当前节点当前节点覆盖的编码单元均只使用帧间预测，cons_pred_mode_flag为1，表示对当前节点覆盖的编码块均只使用帧内预测。
如果当前节点在帧内图像区域中(即当前节点所在的图像类型或者片类型(slice_type)为Intra型或I型)，且允许使用IBC模式，则cu_pred_mode值推导为1，无需从码流中解析得到；如果当前节点在帧内图像区域中，且不允许使用IBC模 式，则cu_pred_mode推导为1，cu_skip_flag为0，无需从码流中解析得到。
如果当前节点在帧间图像区域中(即当前节点所在的图像类型或者片类型(slice_type)为Inter型或B型)，则cu_pred_mode值推导为0，无需从码流中解析得到。
其中，IBC预测可归属于帧内预测模式，因为IBC预测的参考像素来自于当前图像中的重建像素。因此，在本申请实施例中，帧内预测可以包括IBC模式。也就是说，在本申请实施例中，使用帧内预测可以是使用IBC模式，也可以是使用普通的帧内预测模式intra，还可以是使用IBC模式+普通的帧内预测模式intra。因此，在本申请实施例汇总，帧内预测也可以理解为是非帧间预测。
可选的，当前节点所在的片的类型(slice type)不是帧内(Intra)类型。
方法二：在当前节点覆盖的任一编码块的预测模式为帧间预测时，对当前节点覆盖的所有编码块使用帧间预测；或者，在当前节点覆盖的任一编码块的预测模式为帧内预测时，对当前节点覆盖的所有编码块使用帧内预测。
该方法实际上是根据当前节点中任一编码块的预测模式确定对当前节点覆盖的所有编码块的预测模式。
可选的，任一编码块为当前节点覆盖的所有编码块中的解码顺序上的第一个编码块。具体的，解析当前节点区域中第一个编码块B0的预测模式，本实施例对第一个编码块B0的预测模式不作限制。在解析B0的预测模式为帧内预测，则当前节点覆盖的所有编码块均使用帧内预测；在解析B0的预测模式为帧间预测，则当前节点覆盖的所有编码块均使用帧间预测。
需要说明的是，上述方法一和方法二执行的步骤可以应用于图8所示的视频解码器24。
步骤2043、采用当前节点的划分方式对当前节点进行划分，不限制当前节点覆盖的所有编码块的预测模式。
可选的，在步骤203或者步骤2042或者步骤2043之后，还包括：
步骤205、解析当前节点覆盖的所有编码块的预测块和残差信息。
步骤206、解码各编码块，得到当前节点对应的图像块的重建信号。
本实施例中步骤205和步骤206同图9所示实施例的步骤105和步骤106，具体参见上述实施例，此处不再赘述。
本实施例提供的图像预测方法，通过获取当前节点的划分方式，根据当前节点的尺寸和亮度块的划分方式，确定基于亮度块的划分方式对当前节点进行划分是否会得到第一预设尺寸的亮度块，在确定基于亮度块的划分方式对当前节点进行划分会得到第一预设尺寸的亮度块的情况下，进一步判断基于色度块的划分方式对当前节点进行划分是否会得到第二预设尺寸的色度块，在确定基于色度块的划分方式对当前节点进行划分会得到第二预设尺寸的色度块的情况下，对当前节点覆盖的所有编码块均使用帧内预测，或者均使用帧间预测。上述方法对当前节点的所有编码块均使用帧内或者均使用帧间预测，可以实现对当前节点的所有编码块的并行处理，提高图像预测的处理性能，从而提升编解码的处理速度。
下面结合两个具体实例，对图11所示实施例提供的图像预测方法进行说明。
第一个实例适用于视频数据格式YUV为4：2：0或4：2：2，或者仅适用于视频数据格式YUV为4：2：0。
本实例的图像预测方法，包括：
步骤1、获取当前节点的划分方式。
步骤2、判断当前节点的面积和划分方式是否满足如下条件A的至少一项：
(1)当前节点的面积等于32且当前节点的划分方式为竖直二分或者水平二分；
(2)当前节点的面积等于64且当前节点的划分方式为竖直三分、水平三分或者四叉树划分。
如果当前节点的面积和划分方式满足条件A的至少一项，则执行步骤3。
步骤3、限制当前节点覆盖的所有编码块均使用帧内预测。
可选的，将cons_pred_mode_flag值设置为1。
如果当前节点的面积和划分方式不满足上述条件A，则执行步骤4。
步骤4、判断当前节点的面积和划分方式是否满足如下条件B的至少一项：
(1)当前节点的面积S满足S/2<th1且当前节点的划分方式为竖直二分或者水平二分；
(2)当前节点的面积S满足S/4<th1且当前节点的划分方式为竖直三分、水平三分或者四叉树划分。
其中，阈值th1与视频数据格式相关，例如，当视频数据格式为YUV 4:2:0时，th1为64，当视频数据格式为YUV 4:2:2时，th1为32。
如果当前节点的面积和划分方式满足条件B的至少一项，则执行步骤5。
步骤5、从码流中解析标志位cons_pred_mode_flag，根据cons_pred_mode_flag的值来确定当前节点覆盖区域的编码单元均使用帧间预测或者均使用帧内预测。
如果当前节点的面积和划分方式不满足上述条件B，则执行步骤6。
步骤6、使用当前节点的划分方式对当前节点进行划分，不限制当前节点覆盖的所有编码块的预测模式。
可选的，在步骤6之后，还包括：
步骤7、解析当前节点覆盖的所有编码块的预测块和残差信息。
步骤8、解码各编码块，得到当前节点对应的图像块的重建信号。
第二个实例适用于视频数据格式YUV为4:2:0。
本实例的图像预测方法，包括：
步骤1、获取当前节点的划分方式。
步骤2、判断当前节点的面积和划分方式是否满足条件C：
当前节点的面积等于64且当前节点使用水平三分、竖直三分或四叉树划分。
如果当前节点的面积和划分方式满足条件C，则执行步骤3。
步骤3、当前节点覆盖区域的编码单元均使用帧内预测。
可选的，cons_pred_mode_flag设置为1。
如果当前节点的面积和划分方式不满足条件C，则执行步骤4。
步骤4、判断当前节点的面积和划分方式是否满足条件D的至少一项：
(1)当前节点的面积等于64且当前节点使用水平二分或竖直二分；
(2)当前节点的面积等于128且当前节点使用水平三分或竖直三分。
如果当前节点的面积和划分方式满足上述条件D的至少一项，则执行步骤5。
步骤5、从码流中解析标志位cons_pred_mode_flag，根据cons_pred_mode_flag的值来确定当前节点覆盖区域的编码单元均使用帧间预测或者均使用帧内预测。
如果当前节点的面积和划分方式不满足上述条件D，则执行步骤6。
步骤6、使用当前节点的划分方式对当前节点进行划分，不限制当前节点覆盖的所有编码块的预测模式。
可选的，在步骤6之后，还包括：
步骤7、解析当前节点覆盖的所有编码块的预测块和残差信息。
步骤8、解码各编码块，得到当前节点对应的图像块的重建信号。
图12是本申请实施例提供的第四种图像预测方法的流程示意图。如图12所示，本实施例提供的图像预测方法包括：
步骤301、获取当前节点的划分方式。
具体的，解析当前节点的划分信息，若划分信息指示对当前节点的色度块进行划分，则进一步确定当前节点的色度块的划分方式。其中，色度块的划分方式包括四叉树划分、竖直二分、水平二分、竖直三分、水平三分的至少一种，当然还可以是其他的划分方式，对此本实施例不作具体限定。
步骤302、根据当前节点的尺寸和划分方式，确定基于划分方式对当前节点进行划分是否会得到具有第二预设尺寸的色度块。
在确定基于划分方式对当前节点进行划分会得到具有第二预设尺寸的色度块的情况下，执行步骤303；在确定基于划分方式对当前节点进行划分不会得到具有第二预设尺寸的色度块的情况下，执行步骤304。
本实施例的步骤302同图11所示实施例的步骤2041，具体可参见上述实施例，此处不再赘述。
可选的，步骤302可以包括：根据所述当前节点的尺寸和划分方式，确定基于所述划分方式对当前节点进行划分是否会得到具有第三预设尺寸的亮度块。
可选的，该具有第三预设尺寸的亮度块可以为4×4、4×8、或者8×4的亮度块。
可选的，判断基于所述划分方式对当前节点进行划分是否会得到第二预设尺寸的色度块，可以包括：
1)当前节点的亮度块的采样点数量为64，且该划分方式为四叉树划分；或者，
2)当前节点的亮度块的采样点数量为64，且该划分方式为三叉树划分；或者，
3)当前节点的亮度块的采样点数量为32，且该划分方式为二叉树划分；或者，
4)当前节点的亮度块的采样点数量为64，且该划分方式为二叉树划分；或者，
5)当前节点的亮度块的采样点数量为128，且该划分方式为三叉树划分。
可选的，第二预设尺寸的色度块可以为像素尺寸为2×4、或者4×2的色度块，而不包括像素尺寸为2×2的色度块。相似的，具有第三预设尺寸的亮度块可以为像素尺寸为4×8、或者8×4的亮度块，而不包括像素尺寸为4×4的亮度块。相应的，判断基于所述划分方式对当前节点进行划分是否会得到第二预设尺寸的色度块，可以包括：
1)当前节点的亮度块的采样点数量为64，且该划分方式为二叉树划分；或者，
2)当前节点的亮度块的采样点数量为128，且该划分方式为三叉树划分。
步骤303、对当前节点覆盖的所有编码块使用帧内预测，或者对当前节点覆盖的所有编码块使用帧间预测。
对当前节点覆盖的所有编码块使用帧内预测，还是对当前节点覆盖的所有编码块使用帧间预测，可以通过图11所示实施例的步骤2042确定，具体可参见上述实施例，此处不再赘述。
步骤304、采用当前节点的划分方式对当前节点进行划分，不限制当前节点覆盖的所有编码块的预测模式。
本实施例的步骤304同图9所示实施例的步骤104，具体参见上述实施例，此处不再赘述。
可选的，在步骤303或者步骤304之后，还包括：
步骤305、解析当前节点覆盖的所有编码块的预测块和残差信息。
步骤306、解码各编码块，得到当前节点对应的图像块的重建信号。
本实施例中步骤305和步骤306同图9所示实施例的步骤105和步骤106，具体参见上述实施例，此处不再赘述。
本实施例提供的图像预测方法，通过获取当前节点的划分方式，根据当前节点的尺寸和划分方式，确定基于划分方式对当前节点进行划分是否会得到具有第二预设尺寸的色度块，在确定基于划分方式对当前节点进行划分会得到第二预设尺寸的色度块的情况下，对当前节点覆盖的所有编码块使用帧内预测，或者对当前节点覆盖的所有编码块使用帧间预测。上述方法对当前节点的所有编码块均使用帧内或者均使用帧间预测，可以实现对当前节点的所有编码块的并行处理，提高图像预测的处理性能，从而提升编解码的处理速度。
图13是本申请实施例提供的第五种图像预测方法的流程示意图。在图12所示实施例的基础上，如图13所示，在确定基于划分方式对当前节点进行划分会得到具有第二预设尺寸的色度块的情况下，步骤304，可以包括：
步骤3041、判断基于划分方式对当前节点进行划分是否会得到第一预设尺寸的亮度块。
在确定基于划分方式对当前节点进行划分会得到第一预设尺寸的亮度块的情况下，执行步骤3042；在确定基于划分方式对当前节点进行划分不会得到第一预设尺寸的亮度块的情况下，执行步骤3043。
具体的，根据当前节点的尺寸和亮度块的划分方式，确定基于亮度块的划分方式对当前节点进行划分是否会得到具有第一预设尺寸的亮度块。其中，第一预设尺寸的亮度块是指像素尺寸为4×4的亮度块。具体确定过程同图10所示实施例的步骤202，可参见上述实施例，此处不再赘述。
步骤3042、对当前节点覆盖的所有编码块使用帧内预测。
步骤3043、采用当前节点的划分方式对当前节点进行划分，不限制当前节点覆盖的所有编码块的预测模式。
可选的，在步骤303或者步骤3042或者步骤3043之后，还包括：
步骤305、解析当前节点覆盖的所有编码块的预测块和残差信息。
步骤306、解码各编码块，得到当前节点对应的图像块的重建信号。
本实施例中步骤305和步骤306同图9所示实施例的步骤105和步骤106，具体参见上述实施例，此处不再赘述。
本实施例提供的图像预测方法，通过获取当前节点的划分方式，根据当前节点的尺寸和划分方式，确定基于划分方式对当前节点进行划分是否会得到具有第二预设尺寸的色度块，在确定基于划分方式对当前节点进行划分不会得到第二预设尺寸的色度块的情况下，进一步判断基于划分方式对当前节点进行划分是否会得到第一预设尺寸的亮度块，在确定基于划分方式对当前节点进行划分会得到第一预设尺寸的亮度块的情况下，对当前节点覆盖的所有编码块使用帧内预测。上述方法对当前节点的所有编码块均使用帧内或者均使用帧间预测，可以实现对当前节点的所有编码块的并行处理，提高图像预测的处理性能，从而提升编解码的处理速度。
图14是本申请实施例提供的第六种图像预测方法的流程示意图。本实施例提供的图像预测方法应用于图8所示的视频编码器18。如图14所示，本实施例提供的方法包括：
步骤401、获取当前节点的划分方式。
其中，当前节点所在的片(slice)类型为B或者P。应理解，在当前节点所在的片(slice)类型为I的情况下，应默认对对当前节点覆盖的所有编码块使用帧内预测。
在解码端，可以通过解析码流或者通过已获得的参数获取当前节点的划分方式。
在编码端，一般会先判断当前节点允许的划分方式，再使用使用率失真优化(Rate-distortion optimization，RDO)方法，确定出最优的划分方式，作为当前节点的划分方式。此步骤为现有技术，在此不做详细说明。
步骤402、判断当前节点的尺寸和划分方式是否满足第一预设条件中的其中一项。
其中，第一预设条件可以包括：
1)当前节点的亮度块的采样点数量为64，且当前节点的划分方式为四叉树划分； 或者，
2)当前节点的亮度块的采样点数量为64，且当前节点的划分方式为三叉树划分；或者，
3)当前节点的亮度块的采样点数量为32，且当前节点的划分方式为二叉树划分。
其中，当前节点的亮度块的采样点数量即当前节点对应的图像块的亮度像素个数(像素尺寸)，可以根据当前节点的宽和高的乘积得到。
在另一种实施方式中，所述预设条件一还包括以下条件4)：
4)当前节点按照所述划分方式划分会得到预设尺寸的亮度块，所述预设尺寸为4x4或者8x8。
需要说明的是，满足第一预设条件中的其中一项可能得到第一预设尺寸(4x4或者8x8)的亮度块，可能得到第二预设尺寸(2x4或者4x2)的色度块。
在本步骤中，当前节点的尺寸和划分方式满足第一预设条件中的其中一项，则执行步骤403；否则，当前节点的尺寸和划分方式不满足第一预设条件中的所有条件，则执行步骤404。
步骤403、对当前节点覆盖的所有编码块使用帧内预测。
可选的，在确定当前节点覆盖的所有编码块均使用帧内预测的情况下，无需将mode_constraint_flag的值写入码流，可以将mode_constraint_flag的值设置为1，对应的，解码端也可以根据同样的方法推导出mode_constraint_flag的值为1。
步骤404、判断当前节点的尺寸和划分方式是否满足第二预设条件中的其中一项。
其中，第二预设条件包括：
1)当前节点的亮度块的采样点数量为64，且当前节点的划分方式为竖直二叉树或者水平二叉树。或者，
2)当前节点的亮度块的采样点数量为128，且当前节点的划分方式为竖直三叉树或者水平三叉树。
在另一种实施方式中，所述预设条件二还包括条件3)
3)当前节点按照所述划分方式划分会得到预设尺寸的色度块，所述预设尺寸为2x4或者4x2。
在本步骤中，当前节点的尺寸和划分方式满足第二预设条件中的其中一项，则执行步骤405,；当前节点的尺寸和划分方式不满足第二预设条件中的所有条件，则执行步骤406。
步骤405、对当前节点覆盖的所有编码块使用帧内预测，或者对当前节点覆盖的所有编码块使用帧间预测。
在本实施例中可以通过如下几种方式确定当前节点的所有编码块使用的预测模式：
对于编码器或者编码端而言，一种实现方式中，如果当前节点所在的图像类型或者片类型(slice)是I型，确定当前节点内的所有编码块仅适用帧内预测(非帧间预测)。可选的，无需将mode_constraint_flag写入码流，可以将mode_constraint_flag的值设置为1。
对于编码器或者编码端而言，如果当前节点所在的图像类型或者片类型(slice)不是I型，使用率失真优化(Rate-distortion optimization，RDO)方法或者其他方法来 确定mode_constraint_flag的值。
其中，RDO方法是编码器分别计算当前节点覆盖的所有编码块均使用帧间预测和均使用帧内预测时的率失真代价(RD cost)，比较两种预测模式下的率失真代价的值，率失真代价值最小的预测模式确定为最终的预测模式。如果率失真值最小的预测模式为帧内预测，则将mode_constraint_flag设置为1；如果率失真最小的预测模式为帧间预测，则将mode_constraint_flag的值设置为0，将mode_constraint_flag的值写入码流。
示例性的，编码器先计算当前节点覆盖的所有编码块均使用帧间预测时的RD cost，然后计算使用帧内预测时的RD cost，如果当前节点覆盖的所有编码块均使用帧间预测时无残差(例如为skip模式)，则确定当前节点覆盖的所有编码块均使用帧间预测，将mode_constraint_flag的值设置为0，无需再计算帧内预测时的RD cost。编码器还可以先计算当前节点覆盖的所有编码块均使用帧内预测时的RD cost，然后计算使用帧间预测时的RD cost，将RD cost最小的预测模式确定为最终的预测模式。
需要指出的是，如果当前节点在帧内图像区域中(即当前节点所在的图像类型或者片类型(slice_type)为Intra型或I型)，且允许使用IBC模式，则pred_mode_flag值默认为1。如果当前节点在帧内图像区域中，且不允许使用IBC模式，则pred_mode_flag默认为1，cu_skip_flag默认为0(表示当前块不使用skip模式)。如果当前节点在帧内图像区域中(即当前节点所在的图像类型或者片类型(slice_type)为intra型或I型)，则mode_constraint_flag默认为1。
对于解码端或者解码器而言，在一种方式中，可以是解析所述当前节点的预测模式状态标识(mode_constraint_flag)；在所述预测模式状态标识的值为第一值的情况下，对所有属于所述当前节点的的编码块进行帧间预测；或者，在所述预测模式状态标识的值为第二值的情况下，对所有属于所述当前节点的的编码块进行帧内预测。
步骤406、采用当前节点的划分方式对当前节点进行划分，不限制当前节点覆盖的所有编码块的预测模式。
可选的，在步骤403、405、或者406之后，该方法还可以包括：
步骤407、根据当前节点的预测模式确定对当前节点的亮度块和色度块是否继续划分。
在确定当前节点内的所有编码块仅使用帧内预测，按照划分方式对当前节点包括的亮度块进行划分，得到划分后的亮度块，对划分后的亮度块使用帧内预测；将当前节点包括的色度块作为色度编码块，对色度编码块使用帧内预测。也就是说，如果确定当前节点内所有编码块均使用帧内预测，则对当前节点的亮度块按照亮度块的划分方式进行划分，得到N个亮度编码树节点；对当前节点的色度块不划分，得到一个色度编码块(简称色度CB)。其中，N个亮度编码树节点可以限制为不再继续划分，或者不做此限制。如果亮度编码树节点继续划分，则解析其划分方式进行递归划分，当亮度编码树节点不再划分时，它对应一个亮度编码块(简称为亮度CB)。亮度CB使用帧内预测得到亮度CB对应的亮度预测块。色度CB使用帧内预测得到色度CB对应的色度预测块，色度预测块和色度CB的尺寸大小相同。
在确定当前节点内的所有编码块仅使用帧内预测，在另一种实现方式中，按照划分方式对当前节点包括的亮度块和色度块进行划分，得到划分后的节点，当编码树节点不再划分时，它对应一个编码单元，包括亮度编码单元和色度编码单元，对划分后的亮度编码单元和色度编码单元使用帧内预测。
在确定当前节点内的所有编码块仅使用帧间预测，一种实现方式中，按照划分方式对当前节点包括的亮度块进行划分，得到划分后的亮度块，对划分后的亮度块使用帧间预测；按照划分方式对当前节点包括的色度块进行划分，得到划分后的色度块，对划分后的色度块使用帧间预测。也就是说，如果确定当前节点的所有编码块均使用帧间预测，则对当前节点的亮度块按照亮度块的划分方式进行划分，得到N个亮度编码树节点；对当前节点的色度块按照色度块的划分方式进行划分，得到M个色度编码树节点。其中，N和M为正整数，N和M可以相同，也可以不同。对于N个亮度编码树节点和M个色度编码树节点可以限制为不再继续划分，或者不做此限制。不再继续划分时，N个亮度编码树节点对应当前节点的N个亮度CB，M个色度编码树节点对应当前节点的M个色度CB。N个亮度CB使用帧间预测得到对应的亮度预测块，M个色度CB使用帧间预测得到对应的色度预测块。
在确定当前节点内的所有编码块仅使用帧间预测，一种实现方式中，按照划分方式对当前节点包括的亮度块进行划分，得到划分后的亮度块，对划分后的亮度块使用帧间预测；按照划分方式对当前节点包括的色度块进行划分，得到划分后的色度块，对划分后的色度块使用帧间预测。也就是说，如果确定当前节点的所有编码块均使用帧间预测，则对当前节点的亮度块按照亮度块的划分方式进行划分，得到N个亮度编码树节点；对当前节点的色度块按照色度块的划分方式进行划分，得到M个色度编码树节点。其中，N和M为正整数，N和M可以相同，也可以不同。对于N个亮度编码树节点和M个色度编码树节点可以限制为不再继续划分，或者不做此限制。不再继续划分时，N个亮度编码树节点对应当前节点的N个亮度CB，M个色度编码树节点对应当前节点的M个色度CB。N个亮度CB使用帧间预测得到对应的亮度预测块，M个色度CB使用帧间预测得到对应的色度预测块。
特别的，如果当前节点内的所有编码块仅使用帧间预测，且如果当前节点按照所述划分方式划分会得到子节点，如果子节点还需继续划分，且按照子节点的划分方式划分会得到预设尺寸的亮度块，例如预设尺寸为4x4(即宽和高均为4)，则所述子节点的划分方式不被允许，或者该子节点不能继续被划分。具体的，如果节点被限制仅使用帧间预测，且节点的亮度采样点数为32(或者节点的宽和高的乘积为32)，则节点不允许使用二叉树划分(包括水平二叉树和竖直二叉树划分)。如果节点被限制仅使用帧间预测，且节点的亮度采样点数为64(或者节点的宽和高的乘积为64)，则节点不允许使用三叉树划分(包括水平三叉树和竖直三叉树划分)。此判断方法对于视频数据格式为YUV4:2:0和YUV4:2:2均适用。
例如，如果当前节点的尺寸为8x8且使用水平二叉树(或者竖直二叉树)划分产生两个8x4(或两个4x8)的节点，8x4(或4x8)的节点继续划分会产生4x4的块，因此，8x4(或4x8)的节点不能使用竖直二叉树划分(或水平二叉树划分)，或者不能继续划分。又如，如果当前节点的亮度块的采样点数量为128，且划分方式为水 平三叉树划分或者竖直三叉树划分，则可能会得到亮度块的采样点数量为64，而所述采样点数量为64的亮度节点如果使用子节点的划分方式水平三叉树或者竖直三叉树划分，会得到4x4的亮度块，因此当已经被限制仅使用帧间预测时，对于采样点数量为64的节点不能使用水平三叉树或者竖直三叉树划分，或者不能继续被划分。
步骤408、对当前节点划分得到的CU的编码块进行预测，得到编码块的预测值。
对于编码器或者编码端而言，如果当前节点内的所有编码块仅使用帧内预测，编码端使用使用率失真优化(Rate-distortion optimization，RDO)方法或者其他方法确定当前编码块使用的最优的帧内预测模式，当前编码块使用对应的帧内预测模式进行预测，得到当前块的预测值。
对于编码器或者编码端而言，如果当前节点内的所有编码块仅使用帧间预测，编码端使用使用率失真优化方法或者其他方法确定当前编码块使用的最优的帧间预测模式，当前编码块使用对应的帧间预测模式进行预测，得到当前块的预测值。
同时，编码端将CU级相关的语法元素的值赋值，按照CU级的语法定义准则，将各个语法元素的值写入码流。例如，如果当前节点内的所有编码块仅使用帧内预测，则pred_mode_flag的值设置为1不写入码流，不出现在码流中。如果当前节点内的所有编码块仅使用帧内预测，且确定出不使用IBC模式，则cu_skip_flag(或skip_flag)的值为0，不写入码流，否则需要确定cu_skip_flag的值后，写入码流，传输给解码端。
如果当前节点内的所有编码块仅使用帧间预测，pred_mode_flag的值设置为0，不写入码流，不出现在码流中。pred_mode_ibc_flag设置为0，不写入码流，不出现在码流中。
对于解码器或者解码端而言，如果当前节点内的所有编码块仅使用帧内预测，可以通过解析码流或者通过已获得的参数确定确定当前编码块使用的最优的帧内预测模式，当前编码块使用对应的帧内预测模式进行预测，得到当前块的预测值。
对于解码器或者解码端而言，如果当前节点内的所有编码块仅使用帧间预测，可以通过解析码流或者通过已获得的参数确定当前编码块使用的最优的帧间预测模式，当前编码块使用对应的帧间预测模式进行预测，得到当前块的预测值。
步骤409、获取当前节点内的图像块的重建信号。
对于编码器或者编码端而言，利用帧内预测或者帧间预测得到预测信息之后，当前编码块内像素点的像素值减去对应的预测信息(或预测值)便得到残差信息，然后利用离散余弦变换(Discrete Cosine Transformation，DCT)等方法对残差信息进行变换，再使用量化熵编码得到码流。编码端将残差信息传到解码端。预测信号加上重建残差信号之后需进一步进行滤波操作，进而得到重建信号，并将其作为后续编码的参考信号。特别的，如果编码块使用的是skip模式，则无残差信息，无需进行变换，预测值即为最后的重建值。
对于解码器或者解码端而言，预测信号加上重建残差信号之后需进一步进行滤波操作，进而得到重建信号。进一步地，并将得到的重建信号作为后续编码的参考信号。特别的，如果编码块使用的是skip模式，则无残差信息，无需进行变换，预测值即为最后的重建值。
例如，由各CU的预测块对各CU执行帧间预测处理或帧内预测处理，得到各CU的帧间预测图像或帧内预测图像。再根据各CU的残差信息，将变换系数经过反量化和反变换处理得到残差图像，并叠加到对应区域的预测图像上，产生重建图像。
本实施例从视频解码端角度对图像预测方法进行描述，视频解码器根据当前节点的尺寸和划分方式确定是否对当前节点的所有编码块均使用帧内或者均使用帧间预测，可以实现对当前节点的所有编码块的并行处理，提高图像预测的处理性能，从而提升解码的处理速度。
本实施例提供的图像预测方法应用于图8所示的视频编码器18和/或视频解码器24。本实施例包括：
步骤501、获取当前节点的划分方式。
本实施例的步骤501与图9所示实施例的步骤101相同，此处不再赘述。
步骤502、根据以下方法导出变量modeTypeCondition的值
如果以下预设条件一中的一个或多个成立，则modeTypeCondition的值为第一值，例如0。
1)当前节点所在的图像类型或者片(Slice)类型为I型(slice_type＝＝I)，且qtbtt_dual_tree_intra_flag的值为1。
2)当前节点的预测模式类型为仅使用帧内预测或者帧间预测，即已被限制仅使用帧间预测或者帧内预测(非帧间预测)。
3)色度采样结构为单色采样结构(Monochrome)或者4:4:4结构。例如，chroma_format_idc的值为0或者3。
在另一种实施例中，预设条件一还包括以下条件4):
4)色度采样结构为单色采样结构(Monochrome)或者4:4:4或者4:2:2结构。例如，chroma_format_idc的值为0或者3或者2。
否则，如果以下预设条件二中的一项或者多项成立，则modeTypeCondition的值为第二值，例如1。
1)当前节点的亮度块的宽和高的乘积为64，且当前节点的划分方式为四叉树划分；
2)当前节点的亮度块的宽和高的乘积为64，且当前节点的划分方式为水平三叉树或者竖直三叉树划分；
3)当前节点的亮度块的宽和高的乘积为32，且当前节点的划分方式为水平二叉树或者竖直二叉树划分。
否则，如果以下预设条件三中的一项或者多项成立，并且色度采样结构为4:2:0(chroma_format_idc的值为1)，则modeTypeCondition的值根据以下公式推导：1+(slice_type！＝I？1:0)。
1)当前节点的亮度块的宽和高的乘积为64，且当前节点的划分方式为水平二叉树或者竖直二叉树划分；
2)当前节点的亮度块的宽和高的乘积为128，且当前节点的划分方式为水平三叉树或者竖直三叉树划分.
需要说明的是，如表3所示，为色度采样结构与chroma_format_idc的对应关系。
表3
chroma_format_idc separate_colour_plane_flag Chroma format SubWidthC SubHeightC
Figure PCTCN2020070976-appb-000004
在单色采样(Monochrome)中，无色度分量格式，只存在亮度分量的序列。
在4：2：0采样中，两个色度分量的宽度为对应亮度分量宽度的一半，色度分量的高度为亮度分量高度的一半。
在4：2：2采样中，两个色度分量的高与对应的亮度分量相同，色度分量宽度为对应亮度分量宽度的一半。
在4：4：4采样中，取决于separate_colour_plane_flag的值：如果separate_colour_plane_flag等于0，则两个色度分量的宽度和高度分别与亮度高度和宽度相同。否则(separate_colour_plane_flag等于1)，将三个分量分别以单色采样图像进行编码。
separate_colour_plane_flag equal to 1 specifies that the three colour components of the 4:4:4 chroma format are coded separately.separate_colour_plane_flag equal to 0 specifies that the colour components are not coded separately.
qtbtt_dual_tree_intra_flag equal to 1 specifies that for I slices,each CTU is split into coding units with 64x64 luma samples using an implicit quadtree split and that these coding units are the root of two separate coding_tree syntax structure for luma and chroma.qtbtt_dual_tree_intra_flag equal to 0 specifies separate coding_tree syntax structure is not used for I slices.When qtbtt_dual_tree_intra_flag is not present,it is inferred to be equal to 0.
步骤503、根据modeTypeCondition的值确定当前节点内所有编码单元的预测模式类型。
具体的，如果modeTypeCondition的值为1，则限制当前节点内所有编码单元均使用帧内预测(MODE_INTRA)。否则，如果modeTypeCondition的值为2，则从码流中解析语法元素mode_constraint_flag的值，如果mode_constraint_flag的值为0，则当前节点内所有编码单元均使用帧间预测(MODE_INTER)，值为1，则当前节点内所 有编码单元均使用帧内预测(非帧间预测/MODE_INTRA)。
否则，当前节点内所有的编码单元的预测模式类型不做限定，与当前节点的预测模式类型相同。
步骤504、确定当前节点对应的色度块和亮度块是否继续划分，得到色度编码单元和亮度编码单元。
(与步骤407相同。)
在确定当前节点内的所有编码块仅使用帧内预测，按照划分方式对当前节点包括的亮度块进行划分，得到划分后的亮度块，对划分后的亮度块使用帧内预测；将当前节点包括的色度块作为色度编码块，对色度编码块使用帧内预测。也就是说，如果确定当前节点内所有编码块均使用帧内预测，则对当前节点的亮度块按照亮度块的划分方式进行划分，得到N个亮度编码树节点；对当前节点的色度块不划分，得到一个色度编码块(简称色度CB)。其中，N个亮度编码树节点可以限制为不再继续划分，或者不做此限制。如果亮度编码树节点继续划分，则解析其划分方式进行递归划分，当亮度编码树节点不再划分时，它对应一个亮度编码块(简称为亮度CB)。亮度CB使用帧内预测得到亮度CB对应的亮度预测块。色度CB使用帧内预测得到色度CB对应的色度预测块，色度预测块和色度CB的尺寸大小相同。
在确定当前节点内的所有编码块仅使用帧内预测，在另一种实现方式中，按照划分方式对当前节点包括的亮度块和色度块进行划分，得到划分后的节点，当编码树节点不再划分时，它对应一个编码单元，包括亮度编码单元和色度编码单元，对划分后的亮度编码单元和色度编码单元使用帧内预测。
在确定当前节点内的所有编码块仅使用帧间预测，一种实现方式中，按照划分方式对当前节点包括的亮度块进行划分，得到划分后的亮度块，对划分后的亮度块使用帧间预测；按照划分方式对当前节点包括的色度块进行划分，得到划分后的色度块，对划分后的色度块使用帧间预测。也就是说，如果确定当前节点的所有编码块均使用帧间预测，则对当前节点的亮度块按照亮度块的划分方式进行划分，得到N个亮度编码树节点；对当前节点的色度块按照色度块的划分方式进行划分，得到M个色度编码树节点。其中，N和M为正整数，N和M可以相同，也可以不同。对于N个亮度编码树节点和M个色度编码树节点可以限制为不再继续划分，或者不做此限制。不再继续划分时，N个亮度编码树节点对应当前节点的N个亮度CB，M个色度编码树节点对应当前节点的M个色度CB。N个亮度CB使用帧间预测得到对应的亮度预测块，M个色度CB使用帧间预测得到对应的色度预测块。
在确定当前节点内的所有编码块仅使用帧间预测，一种实现方式中，按照划分方式对当前节点包括的亮度块进行划分，得到划分后的亮度块，对划分后的亮度块使用帧间预测；按照划分方式对当前节点包括的色度块进行划分，得到划分后的色度块，对划分后的色度块使用帧间预测。也就是说，如果确定当前节点的所有编码块均使用帧间预测，则对当前节点的亮度块按照亮度块的划分方式进行划分，得到N个亮度编码树节点；对当前节点的色度块按照色度块的划分方式进行划分，得到M个色度编码树节点。其中，N和M为正整数，N和M可以相同，也可以不同。对于N个亮度编码树节点和M个色度编码树节点可以限制为不再继续划分，或者不做此限制。不再继 续划分时，N个亮度编码树节点对应当前节点的N个亮度CB，M个色度编码树节点对应当前节点的M个色度CB。N个亮度CB使用帧间预测得到对应的亮度预测块，M个色度CB使用帧间预测得到对应的色度预测块。
特别的，如果当前节点内的所有编码块仅使用帧间预测，且如果当前节点按照所述划分方式划分会得到子节点，如果子节点还需继续划分，且按照子节点的划分方式划分会得到预设尺寸的亮度块，例如预设尺寸为4x4(即宽和高均为4)，则所述子节点的划分方式不被允许，或者该子节点不能继续被划分。具体的，如果节点被限制仅使用帧间预测，且节点的亮度采样点数为32(或者节点的宽和高的乘积为32)，则节点不允许使用二叉树划分(包括水平二叉树和竖直二叉树划分)。如果节点被限制仅使用帧间预测，且节点的亮度采样点数为64(或者节点的宽和高的乘积为64)，则节点不允许使用三叉树划分(包括水平三叉树和竖直三叉树划分)。此判断方法对于视频数据格式为YUV4:2:0和YUV4:2:2均适用。
例如，如果当前节点的尺寸为8x8且使用水平二叉树(或者竖直二叉树)划分产生两个8x4(或两个4x8)的节点，8x4(或4x8)的节点继续划分会产生4x4的块，因此，8x4(或4x8)的节点不能使用竖直二叉树划分(或水平二叉树划分)，或者不能继续划分。又如，如果当前节点的亮度块的采样点数量为128，且划分方式为水平三叉树划分或者竖直三叉树划分，则可能会得到亮度块的采样点数量为64，而所述采样点数量为64的亮度节点如果使用子节点的划分方式水平三叉树或者竖直三叉树划分，会得到4x4的亮度块，因此当已经被限制仅使用帧间预测时，对于采样点数量为64的节点不能使用水平三叉树或者竖直三叉树划分，或者不能继续被划分。
步骤505、解析编码单元，获取预测模式信息
根据编码单元的预测模式类型，解析帧内或者帧间预测相关的语法元素，得到编码单元最终的预测模式。使用对应的预测模式进行预测，得到预测值。
如果当前节点在帧内图像区域中(即当前节点所在的图像类型或者片类型(slice_type)为Intra型或I型)，且允许使用IBC模式，则cu_pred_mode值推导为1，无需从码流中解析得到；如果当前节点在帧内图像区域中，且不允许使用IBC模式，则cu_pred_mode推导为1，cu_skip_flag为0，无需从码流中解析得到。
如果当前节点在帧间图像区域中(即当前节点所在的图像类型或者片类型(slice_type)为Inter型或B型)，则cu_pred_mode值推导为0，无需从码流中解析得到。
步骤506、解码各编码块，得到当前节点对应的图像块的重建信号。
例如，由各CU的预测块对各CU执行帧间预测处理或帧内预测处理，得到各CU的帧间预测图像或帧内预测图像。再根据各CU的残差信息，将变换系数经过反量化和反变换处理得到残差图像，并叠加到对应区域的预测图像上，产生重建图像。
对应编码端方法：
本实施例提供的图像预测方法应用于图8所示的视频编码器18。本实施例包括：
步骤601、获取当前节点的划分方式。
本实施例的步骤601与步骤501相同，此处不再赘述。
步骤602、根据以下方法导出变量modeTypeCondition的值
如果以下预设条件一中的一个或多个成立，则modeTypeCondition的值为第一值，例如0。
1)当前节点所在的图像类型或者片(Slice)类型为I型(slice_type＝＝I)，且qtbtt_dual_tree_intra_flag的值为1。
2)当前节点的预测模式类型为仅使用帧内预测或者帧间预测，即已被限制仅使用帧间预测或者帧内预测(非帧间预测)。
3)色度采样结构为单色采样结构(Monochrome)或者4:4:4结构。例如，chroma_format_idc的值为0或者3。
在另一种实施例中，预设条件一还包括以下条件4):
4)色度采样结构为单色采样结构(Monochrome)或者4:4:4或者4:2:2结构。例如，chroma_format_idc的值为0或者3或者2。
否则，如果以下预设条件二中的一项或者多项成立，则modeTypeCondition的值为第二值，例如1。
1)当前节点的亮度块的宽和高的乘积为64，且当前节点的划分方式为四叉树划分；
2)当前节点的亮度块的宽和高的乘积为64，且当前节点的划分方式为水平三叉树或者竖直三叉树划分；
3)当前节点的亮度块的宽和高的乘积为32，且当前节点的划分方式为水平二叉树或者竖直二叉树划分。
否则，如果以下预设条件三中的一项或者多项成立，并且色度采样结构为4:2:0(chroma_format_idc的值为1)，则modeTypeCondition的值根据以下公式推导：1+(slice_type！＝I？1:0)。
1)当前节点的亮度块的宽和高的乘积为64，且当前节点的划分方式为水平二叉树或者竖直二叉树划分；
2)当前节点的亮度块的宽和高的乘积为128，且当前节点的划分方式为水平三叉树或者竖直三叉树划分.
步骤603、根据modeTypeCondition的值确定当前节点内所有编码单元的预测模式类型。
具体的，如果modeTypeCondition的值为1，则限制当前节点内所有编码单元均使用帧内预测(MODE_INTRA)。可选的mode_constraint_flag设置为1。
否则，如果modeTypeCondition的值为2，则使用RDO的方法确定出语法元素mode_constraint_flag的值。例如，先计算当前节点内所有编码单元均使用帧间预测时的RD cost，然后计算使用帧内预测时的RD cost，其中，如果当前节点内所有编码单元均使用帧间预测时无残差(例如为skip模式)，则确定当前节点内所有编码单元均使用帧间预测，将mode_constraint_flag的值设置为0，无需再计算帧内预测时的RD cost。 还可以先计算当前节点内所有编码单元均使用帧内预测时的RD cost，然后计算使用帧间预测时的RD cost，再得出RD cost最小的预测模式确定为最终的预测。
否则，当前节点内所有的编码单元的预测模式类型不做限定，与当前节点的预测模式类型相同。
特别的，如果当前节点在帧内图像区域中(即当前节点所在的图像类型或者片类型(slice_type)为Intra型或I型)，且允许使用IBC模式，则pred_mode_flag值默认为1；如果当前节点在帧内图像区域中，且不允许使用IBC模式，则pred_mode_flag默认为1，cu_skip_flag为0。
步骤604、确定当前节点对应的色度块和亮度块的划分方式，得到色度编码单元和亮度编码单元。
具体的，与步骤504相同。
步骤605、对当前节点划分得到的CU的编码块进行预测，得到编码块的预测值。
如果当前节点内的所有编码块仅使用帧内预测，编码端使用使用率失真优化(Rate-distortion optimization，RDO)方法或者其他方法确定当前编码块使用的最优的帧内预测模式，当前编码块使用对应的帧内预测模式进行预测，得到当前块的预测值。
如果当前节点内的所有编码块仅使用帧间预测，编码端使用使用率失真优化方法或者其他方法确定当前编码块使用的最优的帧间预测模式，当前编码块使用对应的帧间预测模式进行预测，得到当前块的预测值。
同时，编码端将CU级相关的语法元素的值赋值，按照CU级的语法定义准则，将各个语法元素的值写入码流。例如，如果当前节点内的所有编码块仅使用帧内预测，则pred_mode_flag的值设置为1不写入码流，不出现在码流中。如果当前节点内的所有编码块仅使用帧内预测，且确定出不使用IBC模式，则cu_skip_flag(或skip_flag)的值为0，不写入码流，否则需要确定cu_skip_flag的值后，写入码流，传输给解码端。
如果当前节点内的所有编码块仅使用帧间预测，pred_mode_flag的值设置为0，不写入码流，不出现在码流中。pred_mode_ibc_flag设置为0，不写入码流，不出现在码流中。
步骤606：获取当前节点内的图像块的重建信号
利用帧内预测或者帧间预测得到预测信息之后，当前编码块内像素点的像素值减去对应的预测信息(或预测值)便得到残差信息，然后利用离散余弦变换(Discrete Cosine Transformation，DCT)等方法对残差信息进行变换，再使用量化熵编码得到码流。编码端将残差信息传到解码端。预测信号加上重建残差信号之后需进一步进行滤波操作，进而得到重建信号，并将其作为后续编码的参考信号。特别的，如果编码块使用的是skip模式，则无残差信息，无需进行变换，预测值即为最后的重建值。
图15是本申请实施例提供的图像预测装置的功能结构示意图。如图15所示，本实施例提供的图像预测装置40，包括：
获取模块41，用于获取当前节点的划分方式；
判断模块42，用于判断基于所述划分方式对所述当前节点进行划分是否会得到具 有预设尺寸的图像块；所述图像块包括亮度块或色度块；
执行模块43，用于在确定基于所述划分方式对所述当前节点进行划分会得到具有所述预设尺寸的图像块的情况下，对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预测。
可选的，所述具有预设尺寸的图像块包括具有第一预设尺寸的亮度块，所述判断模块42，具体用于：根据所述当前节点的尺寸和所述划分方式，确定基于所述划分方式对当前节点进行划分是否会得到具有第一预设尺寸的亮度块。
可选的，在确定基于所述划分方式对当前节点进行划分会得到具有第一预设尺寸的亮度块的情况下，所述执行模块43，具体用于：
对所述当前节点覆盖的所有编码块使用帧内预测。
可选的，在确定基于所述划分方式对当前节点进行划分不会得到具有第一预设尺寸的亮度块的情况下，所述判断模块42，还用于判断基于所述划分方式对当前节点进行划分是否会得到第二预设尺寸的色度块；
在确定基于所述划分方式对所述当前节点进行划分会得到具有所述第二预设尺寸的色度块的情况下，所述执行模块43，具体用于对所述当前节点覆盖的所有编码块使用帧内预测，或者对所述当前节点覆盖的所有编码块使用帧间预测。
可选的，所述具有预设尺寸的图像块包括具有第二预设尺寸的色度块，所述判断模块42，具体用于：根据所述当前节点的尺寸和划分方式，确定基于所述划分方式对当前节点进行划分是否会得到具有第二预设尺寸的色度块。
可选的，在确定基于所述划分方式对当前节点进行划分会得到具有第二预设尺寸的色度块的情况下，所述执行模块43，具体用于：
解析所述当前节点的预测模式状态标识；
在所述预测模式状态标识的值为第一值时，对所述当前节点覆盖的所有编码块使用帧间预测；或者，在所述预测模式状态标识的值为第二值时，对所述当前节点覆盖的所有编码块使用帧内预测。
可选的，在确定基于所述划分方式对当前节点进行划分会得到具有第二预设尺寸的色度块的情况下，所述执行模块43，具体用于：在所述当前节点覆盖的任一编码块的预测模式为帧间预测时，对所述当前节点覆盖的所有编码块使用帧间预测；或者，在所述当前节点覆盖的任一编码块的预测模式为帧内预测时，对所述当前节点覆盖的所有编码块使用帧内预测。
可选的，所述任一编码块为所述当前节点覆盖的所有编码块中的解码顺序上的第一个编码块。
可选的，在确定基于所述划分方式对当前节点进行划分会得到具有第二预设尺寸的色度块的情况下，所述执行模块43，具体用于：
判断基于所述划分方式对当前节点进行划分是否会得到第一预设尺寸的亮度块；
在确定基于所述当前节点的划分方式对当前节点进行划分会得到第一预设尺寸的亮度块的情况下，对所述当前节点覆盖的所有编码块使用帧内预测。
可选的，在确定基于所述划分方式对当前节点进行划分不会得到第一预设尺寸的 亮度块的情况下，所述执行模块43，具体用于：
解析所述当前节点的预测模式状态标识；
在所述预测模式状态标识的值为第一值时，对所述当前节点覆盖的所有编码块使用帧间预测；或者，在所述预测模式状态标识的值为第二值时，对所述当前节点覆盖的所有编码块使用帧内预测。
可选的，在确定基于所述划分方式对当前节点进行划分不会得到第一预设尺寸的亮度块的情况下，所述执行模块43，具体用于：在所述当前节点覆盖的任一编码块的预测模式为帧间预测时，对所述当前节点覆盖的所有编码块使用帧间预测；或者，在所述当前节点覆盖的任一编码块的预测模式为帧内预测时，对所述当前节点覆盖的所有编码块使用帧内预测。
可选的，所述执行模块43，具体用于：
按照所述划分方式对所述当前节点包括的亮度块进行划分，得到划分后的亮度块，对所述划分后的亮度块使用帧内预测，将所述当前节点包括的色度块作为色度编码块，对所述色度编码块使用帧内预测；或者，
按照所述划分方式对所述当前节点包括的亮度块进行划分，得到划分后的亮度块，对所述划分后的亮度块使用帧间预测，按照所述划分方式对所述当前节点包括的色度块进行划分，得到划分后的色度块，对所述划分后的色度块使用帧间预测。
可选的，所述执行模块43，具体用于：
按照所述划分方式对所述当前节点包括的亮度块进行划分，得到划分后的亮度块，对所述划分后的亮度块使用帧内预测，将所述当前节点包括的色度块作为色度编码块，对所述色度编码块使用帧内预测；或者，
按照所述划分方式对所述当前节点包括的亮度块进行划分，得到划分后的亮度块，对所述划分后的亮度块使用帧间预测，将所述当前节点包括的色度块作为色度编码块，对所述色度编码块使用帧间预测。
可选的，在对所述当前节点覆盖的所有编码块使用帧间预测的情况下，所述获取模块41，还用于获取所述当前节点的子节点的子划分方式，所述子节点包括亮度块和色度块；
所述判断模块42，还用于判断基于所述子划分方式对所述当前节点的子节点进行划分是否会得到具有第一预设尺寸的亮度块；
在确定基于所述子划分方式对所述当前节点的子节点进行划分会得到具有第一预设尺寸的亮度块的情况下，所述执行模块43，具体用于对以所述当前节点的子节点采用所述子划分方式之外的划分方式进行划分，得到对应的编码块，并对所述对应的编码块使用帧间预测，或者，将所述当前节点的子节点作为编码块使用帧间预测。
本申请实施例提供的图像预测装置，可以执行上述方法实施例的技术方案，其实现原理和技术效果类似，此处不再赘述。
图16是本申请实施例提供的视频编码设备的硬件结构示意图。如图16所示，本实施例提供的视频编码设备50，包括处理器51和用于存储所述处理器51的可执行指令的存储器52；其中所述处理器51可以执行上述方法实施例中视频编码设备对应的 图像预测方法，其实现原理和技术效果类似，此处不再赘述。
可选的，存储器52既可以是独立的，也可以跟处理器51集成在一起。
当存储器52是独立于处理器51之外的器件时，视频编码设备50还包括：总线53，用于连接存储器52和处理器51。
图17是本申请实施例提供的视频解码设备的硬件结构示意图。如图17所示，本实施例提供的视频解码设备60，包括处理器61和用于存储所述处理器61的可执行指令的存储器62；其中所述处理器61可以执行上述方法实施例中视频解码设备对应的图像预测方法，其实现原理和技术效果类似，此处不再赘述。
可选的，存储器62既可以是独立的，也可以跟处理器61集成在一起。
当存储器62是独立于处理器61之外的器件时，视频解码设备60还包括：总线63，用于连接存储器62和处理器61。
图18是本申请实施例提供的图像预测系统的结构示意图。如图18所示，本实施例提供的图像预测系统，包括视频采集设备70、图16所示实施例的视频编码设备50、图17所示实施例的视频解码设备60以及显示设备80。
其中，所述视频编码设备50分别与所述视频采集设备70和所述视频解码设备60连接，所述视频解码设备60与所述显示设备80连接。
具体的，视频编码设备50接收视频采集设备70发送的视频或图像信息，视频编码设备50可以执行上述方法实施例中视频编码设备50对应的图像预测方法，视频编码设备50将编码后的视频或图像信息发送至视频解码设备60，视频解码设备60可以执行上述方法实施例中视频解码设备60对应的图像预测方法，视频解码设备60将解码后的视频或图像信息发送至显示设备80显示。
本申请实施例提供的图像预测系统包括可以执行上述方法实施例的视频编码设备以及可以执行上述方法实施例的视频解码设备，其实现原理和技术效果类似，此处不再赘述。
本申请实施例还提供一种计算机可读存储介质，其上存储有计算机程序，所述计算机程序被处理器执行以实现上述方法实施例的各个步骤。
本申请实施例还提供一种视频解码方法，所述方法包括：
获取当前节点的划分方式，所述当前节点包括亮度块和色度块；
判断基于所述当前节点的划分方式对所述当前节点继续划分是否会得到色度小块，所述色度小块为小于或者等于第一预设值的色度块或者所述色度小块为块中的像素个数小于或者等于第二预设值的色度块；
如果基于所述当前节点的划分方式对所述当前节点继续划分会得到色度小块，对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测，或者 对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测，从而得到划分得到的编码块的预测信息。
可选的，所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测包括：对以所述当前节点为根节点进行划分得到的所有编码块(coding block)执行帧间预测；或者，
所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测包括：对以所述当前节点为根节点进行划分得到的所有编码块(coding block)执行帧内预测。
可选的，所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测包括：对以所述当前节点为根节点进行划分得到的所有色度小块执行帧间预测；或者，
所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测包括：对以所述当前节点为根节点进行划分得到的所有所有色度小块执行帧内预测。
可选的，所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测包括：对以所述当前节点为根节点进行划分得到的编码单元(coding unit)执行帧间预测；或者，
所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测包括：对以所述当前节点为根节点进行划分得到的编码单元(coding unit)执行帧内预测。
可选的，所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测，或者对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测包括：
解析所述当前节点的节点预测模式标识(cons_pred_mode_flag)；
在所述节点预测模式标识的值为第一值时，对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测；
在所述节点预测模式标识的值为第二值时，对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测。
可选的，所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测，或者对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测包括：
在以所述当前节点为根节点进行划分得到的任一编码块的预测模式为帧间预测时，对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测；
在以所述当前节点为根节点进行划分得到的任一编码块的预测模式为帧内预测时，对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测。
可选的，所述第一预设值为2或4，或者，所述第二预设值为16、8或32。
可选的，所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测包括：
对所述当前节点包括的亮度块按照所述节点的划分方式对所述当前节点包括的亮 度块进行划分，以得到亮度编码块；
对所述亮度编码块进行帧内预测；
将所述当前节点包括的色度块作为色度编码块进行帧内预测。
可选的，所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测，或者对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测包括：
对所述当前节点包括的亮度块按照所述节点的划分方式对所述当前节点包括的亮度块进行划分，以得到亮度编码块；
对所述亮度编码块进行帧间预测或者帧内预测；
将所述当前节点包括的色度块作为色度编码块进行帧间预测或者帧内预测。
可选的，所述将所述当前节点包括的色度块作为色度编码块进行帧间预测或者帧内预测包括：
将所述色度编码块作为色度预测块进行帧内预测；或者，
将所述色度编码块进行划分得到色度预测块，对划分得到的色度预测块进行帧间预测。
本申请实施例还提供一种视频解码方法，所述方法包括：
获取当前节点的划分方式，所述当前节点包括亮度块和色度块；
判断基于所述当前节点的划分方式对所述当前节点继续划分是否会得到具有预设尺寸的亮度块；
如果基于所述当前节点的划分方式对所述当前节点继续划分会得到具有所述预设尺寸的亮度块，对以所述当前节点为根节点进行划分得到的所有编码块(coding block)执行帧内预测，从而得到划分得到的编码块的预测块。
可选的，所述方法还包括：
如果基于所述当前节点的划分方式对所述当前节点继续划分不会得到具有所述预设尺寸的亮度块，判断基于所述当前节点的划分方式对所述当前节点继续划分是否会得到色度小块，所述色度小块为小于或者等于第一预设值的色度块或者所述色度小块为块中的像素个数小于或者等于第二预设值的色度块；
如果基于所述当前节点的划分方式对所述当前节点继续划分会得到色度小块，对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测，或者对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测，从而得到划分得到的编码块的预测块。
可选的，所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测包括：对以所述当前节点为根节点进行划分得到的所有编码块(coding block)执行帧间预测；或者，
所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测包括：对以所述当前节点为根节点进行划分得到的所有编码块(coding block)执行帧内预测。
可选的，所述对以所述当前节点为根节点进行划分得到的编码块(coding block) 执行帧间预测包括：对以所述当前节点为根节点进行划分得到的所有色度小块执行帧间预测；或者，
所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测包括：对以所述当前节点为根节点进行划分得到的所有所有色度小块执行帧内预测。
可选的，所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测包括：对以所述当前节点为根节点进行划分得到的编码单元(coding unit)执行帧间预测；或者，
所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测包括：对以所述当前节点为根节点进行划分得到的编码单元(coding unit)执行帧内预测。
可选的，所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测，或者对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测包括：
解析所述当前节点的节点预测模式标识(cons_pred_mode_flag)；
在所述节点预测模式标识的值为第一值时，对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测；
在所述节点预测模式标识的值为第二值时，对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测。
可选的，所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测，或者对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测包括：
在以所述当前节点为根节点进行划分得到的任一编码块的预测模式为帧间预测时，对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测；
在以所述当前节点为根节点进行划分得到的任一编码块的预测模式为帧内预测时，对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测。
可选的，所述第一预设值为2或4，或者，所述第二预设值为16、8或32。
可选的，所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测包括：
对所述当前节点包括的亮度块按照所述节点的划分方式对所述当前节点包括的亮度块进行划分，以得到亮度编码块；
对所述亮度编码块进行帧内预测；
将所述当前节点包括的色度块作为色度编码块进行帧内预测。
可选的，所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测，或者对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧内预测包括：
对所述当前节点包括的亮度块按照所述节点的划分方式对所述当前节点包括的亮度块进行划分，以得到亮度编码块；
对所述亮度编码块进行帧间预测或者帧内预测；
将所述当前节点包括的色度块作为色度编码块进行帧间预测或者帧内预测。
可选的，所述将所述当前节点包括的色度块作为色度编码块进行帧间预测或者帧内预测包括：
将所述色度编码块作为色度预测块进行帧内预测；或者，
将所述色度编码块进行划分得到色度预测块，对划分得到的色度预测块进行帧间预测。
可选的，所述对以所述当前节点为根节点进行划分得到的编码块(coding block)执行帧间预测包括：
对所述当前节点按照所述当前节点的划分方式对所述当前节点进行划分，得到所述当前节点的子节点；
获取所述当前节点的子节点的子划分方式，所述子节点包括亮度块和色度块；
判断基于所述子划分方式对所述当前节点的子节点继续划分是否会得到具有预设尺寸的亮度块；
如果基于所述子划分方式对所述当前节点的子节点继续划分会得到具有预设尺寸的亮度块，对以所述当前节点的子节点采用所述子划分方式之外的划分方式进行划分，以得到对应的编码单元并对所述对应的编码单元执行帧间预测，或者，将所述当前节点的子节点作为编码单元进行帧间预测。
可选的，所述预设尺寸包括4×4，4×8，8×4，2×4或4×2。
本申请实施例还提供一种视频解码方法，所述方法包括：
获取当前节点的划分方式，所述当前节点包括亮度块和色度块；
在以所述当前节点为根节点进行划分得到的所有编码块(coding block)的预测模式为帧间预测模式时，对所述当前节点按照所述当前节点的划分方式对所述当前节点进行划分，得到所述当前节点的子节点；
获取所述当前节点的子节点的子划分方式，所述子节点包括亮度块和色度块；
判断基于所述子划分方式对所述当前节点的子节点继续划分是否会得到具有预设尺寸的亮度块；
如果基于所述子划分方式对所述当前节点的子节点继续划分会得到具有预设尺寸的亮度块，对以所述当前节点的子节点采用所述子划分方式之外的划分方式进行划分，以得到对应的编码单元并对所述对应的编码单元执行帧间预测，或者，将所述当前节点的子节点作为编码单元执行帧间预测。
本申请实施例提供的第一种视频解码方法涉及一种视频解码中的块划分方式。本实施例中的视频数据格式为YUV4:2:0格式。对YUV4:2:2数据可采用类似的方式。
步骤1：解析节点A的划分方式S，如果节点A继续划分，则执行步骤2；如果当前节点不再划分成子节点，则当前节点对应一个编码单元，解析编码单元信息；
节点A的划分方式可以是四叉树划分、竖直二分、水平二分、竖直三分、水平三分中的至少一种，还可以是其它的划分方式，本申请不做限定。当前节点的划分方式信息可以在码流中传输，通过解析码流中相应的语法元素可解析得到当前节点的划分 方式。当前节点的划分方式也可以基于预设的规则确定，本申请不做限定。
步骤2：判断节点A按照所述的划分方式S划分得到的子节点中是否存在至少一个子节点B的色度块为小块(判断节点A的宽、高，和/或划分方式，和/或节点B的宽和高是否满足所述条件中的至少一个)。如果节点A划分得到的子节点中至少一个子节点B的色度块为小块，则执行步骤3至步骤6
具体的，节点A的至少一个子节点B的色度块为小块的判断方法可使用以下一种。
1)如果节点A的至少一个子节点B的色度块为2x2、2x4、或4x2大小，则节点A的至少一个子节点B的色度块为小块。
2)如果节点A的至少一个子节点B的色度块的宽或高为2，则节点A的至少一个子节点B的色度块为小块。
3)如果节点A包含128个亮度像素且节点A使用三叉树划分，或者如果节点A包含64个亮度像素且节点A使用二叉树划分或者四叉树划分或者三叉树划分，则节点A的至少一个子节点B的色度块为小块。
4)如果节点A包含256个亮度像素且节点使用三叉树划分或者四叉树划分，或者如果节点A包含128个亮度像素且节点使用二叉树划分，则节点A的至少一个子节点B的色度块为小块。
5)如果节点A包含N1个亮度像素且节点A使用三叉树划分，N1为64、128或者256。
6)如果节点A包含N2个亮度像素且节点A使用四叉树划分，N2为64或者256。
7)如果节点A包含N3个亮度像素且节点A使用二叉树划分，N3为64、128或者256。
需要说明的是，节点A包含128个亮度像素点也可以描述为当前节点的面积为128，或者节点A的宽和高的乘积为128，在此不作赘述。
步骤3：限制节点A覆盖区域内所有的编码单元均使用帧内预测或均使用帧间预测。其中，均使用帧内或者帧间预测，可以实现硬件对小块的并行处理，提高了编解码性能。
节点A覆盖区域内所有编码单元均使用帧内预测或均使用帧间预测可通过以下的一种方法确定。
方法一：根据语法表中的标志位来确定。
如果节点A按照划分方式S划分后得到至少一个子节点B的色度块为小块(且节点A的色度块不为小块)，则从码流中解析标志位cons_pred_mode_flag；其中，cons_pred_mode_flag为0表示节点A覆盖区域的编码单元均使用帧间预测，cons_pred_mode_flag为1表示节点A覆盖区域的编码单元均使用帧内预测。cons_pred_mode_flag可以为块划分过程中需要解析的语法元素，当解析该语法元素时，则节点A覆盖区域的编码单元的cu_pred_mode可以不再解析，其值为与cons_pred_mode_flag的值对应的默认值。
需要说明的是，如果节点A的子节点只能使用帧内预测模式，例如节点A在帧内图像中(即节点A所在的图像类型为Intra型或I型)，或者节点A在帧内图像中且 序列不使用IBC技术，则cons_pred_mode_flag默认为1，不出现在码流中。其中，IBC技术可以属于帧间预测，也可以属于帧内预测。
方法二：由节点A区域中第一个节点的预测模式确定。
解析节点A区域中第一个编码单元B0的预测模式(第一个编码单元B0的预测模式不作限制)，如果B0的预测模式为帧内预测，则节点A覆盖区域内所有编码单元均使用帧内预测；如果B0的预测模式为帧间预测，则节点A区域盖区域内所有编码单元均使用帧间预测。
步骤4：根据节点A覆盖区域的编码单元使用的预测模式，决定节点A的色度块和亮度块的划分方式。
如果节点A覆盖区域的编码单元均使用帧内预测模式，则对节点A的亮度块按照所述的划分方式S进行划分，得到N个亮度编码树节点；对节点A的色度块不划分，对应一个色度编码块(简称为色度CB)。其中，N个亮度编码树节点可以限制为不再继续划分，或者不做此限制。如果亮度子节点继续划分，则解析其划分方式进行递归划分，当亮度编码树节点不再划分时，它对应一个亮度编码块(简称为亮度CB)。其中，色度CB对应的色度变换块和色度编码块相同大小，色度预测块和色度编码块相同大小。
如果节点A覆盖区域的编码单元均使用帧间预测模式，则将节点A的亮度块和色度块按照划分方式S继续划分为N个包含亮度块和色度块的编码树节点，这N个编码树节点可继续划分或不划分，不划分时对应于包含亮度块和色度块的编码单元。
步骤5：解析节点A划分得到的CU的预测信息和残差信息。
所述预测信息包括：预测模式(指示帧内预测或非帧内预测模式)、帧内预测模式、帧间预测模式、运动信息等。运动信息可包括预测方向(前向、后向或双向)、参考帧索引(reference index)、运动矢量(motion vector)等信息。
所述残差信息包括：编码块标志位(coded block flag，cbf)、变换系数、变换类型(例如DCT-2,DST-7,DCT-8)等。变换类型可默认为DCT-2变换。
如果节点A划分得到的各CU限制只能使用帧内预测，则节点A划分得到的亮度CB的预测信息解析包括将skip_flag、merge_flag、cu_pred_mode分别默认为0、0和1(即skip_flag、merge_flag、cu_pred_mode均不出现在码流中)，或者skip_flag、cu_pred_mode分别默认为0和1(即skip_flag、cu_pred_mode均不出现在码流中)将解析亮度CB的帧内预测模式信息；节点A划分得到的色度CB的预测信息解析包括解析色度CB的帧内预测模式。色度CB的帧内预测模式的解析方法可以是：1)从码流中解析语法元素得到；2)直接设定为色度帧内预测模式集合中的一种，例如线性模型模式、DM模式(chroma derived mode，DM)和IBC模式等中的一种。
如果节点A划分得到的各CU限制只能使用帧间预测，则节点A划分得到的CU的预测模式解析包括解析skip_flag或/和merge_flag，将cu_pred_mode默认为0，解析帧间预测信息，如融合索引(merge index)、帧间预测方向(inter dir)，参考帧索引(reference index)、运动矢量预测值索引(motion vector predictor index)和运动矢量 差分量(motion vector difference)
其中，skip_flag为跳过模式的标志，值为1表示当前CU使用跳过模式，值为0表示当前CU不使用跳过模式。merge_flag为融合模式标志，值为1表示当前CU使用融合模式；值为0表示不使用融合模式。cu_pred_mode为编码单元预测模式标志，值为1表示当前预测单元使用帧内预测；值为0表示当前预测单元使用普通帧间预测(在码流中标识帧间预测方向、参考帧索引、运动矢量预测值索引、运动矢量差分量等信息)。
需要说明的是，本实施例中所述帧内预测模式为使用编码块所在图像的空域参考像素产生编码块的预测值的预测模式，如直流模式(direct current mode,DC mode)，平面模式(Planar mode)，角度模式(angular mode)，还可能包含模版匹配模式(template matching mode)，IBC模式。
所述帧间预测模式为使用编码块的参考图像中的时域参考像素产生编码块的预测值的预测模式，如跳过模式(Skip mode)，融合模式(Merge mode)，AMVP(advanced motion vector prediction)模式或称普通Inter模式，IBC模式等。
步骤6：解码各CU，得到节点A对应的图像块的重建信号
例如，由各CU的预测信息对各CU执行帧间预测处理或帧内预测处理，得到各CU的帧间预测图像或帧内预测图像。再根据各CU的残差信息，将变换系数经过反量化和反变换处理得到残差图像，并叠加到对应区域的预测图像上，产生重建图像。
通过本实施例的划分方式，将不会产生使用帧内预测的色度小块，从而解决了小块帧内预测问题。
本申请实施例提供的第二种视频解码方法，步骤1、步骤2、步骤3、步骤6与第一种解码方法相同。区别在于：
步骤4：决定节点A的色度块和亮度块的划分方式。
节点A的亮度块按照划分方式S继续划分，产生N个亮度编码树节点。节点A的色度块不再划分，对应一个色度编码块(色度CB)。色度CB对应的色度变换块和色度编码块相同大小。[注：相比实施例一，本实施例中，不管限制的是帧间还是帧内预测模式，色度块总是不划分，亮度块总是按照划分方式S划分，与节点A覆盖区域的预测模式无关]。
步骤5：解析节点A划分得到的CU的预测信息和残差信息。
如果节点A划分得到的各CU限制只能使用帧内预测，处理与实施例一相同。
如果节点A划分得到的各CU限制只能使用帧间预测，则节点A划分得到的亮度CB的预测信息解析包括解析skip_flag或/和merge_flag，将cu_pred_mode默认为0，解析帧间预测信息，如融合索引(merge index)、帧间预测方向(inter dir)，参考帧索引(reference index)、运动矢量预测值索引(motion vector predictor index)和运动矢量差分量(motion vector difference)。由解析得到的帧间预测信息，导出亮度CB中各4x4子块的运动信息。
如果节点A划分得到的各CU限制只能使用帧间预测，则节点A划分得到的色度 CB的预测信息无需解析，将色度CB划分为2x2色度子块(该划分方式可以为划分方式S)，各2x2色度子块的运动信息为各2x2色度子块对应的4x4亮度区域的运动信息。
通过本实施例的划分方式，将不会产生使用帧内预测的色度小块，也不会产生小于16个像素的变换块，解决上述帧内预测问题和系数编码问题。
本申请实施例提供的第三种视频解码方法，步骤1、步骤2、步骤3、步骤4、步骤6与第二种解码方法相同。区别在于：
步骤5：解析节点A划分得到的CU的预测信息和残差信息。
如果节点A划分得到的各CU限制只能使用帧内预测，处理与实施例二相同。
如果节点A划分得到的各CU限制只能使用帧间预测，则节点A划分得到的亮度CB的预测信息解析与实施例二相同。
如果节点A划分得到的各CU限制只能使用帧间预测，则节点A划分得到的色度CB的预测信息无需解析，色度预测块与色度编码块大小相同，色度CB的运动信息为色度CB对应的亮度区域中某个预设位置的运动信息(如亮度区域的中心、右下角或左上角等)。
通过本实施例的划分方式，将不会产生使用帧内预测的色度小块，也不会产生小块变换块，也不会产生使用帧间预测的色度小块。
本申请实施例提供的第四种视频解码方法，包括：
步骤1：与上述第一种视频解码方法的步骤1相同
步骤2：判断节点A按照所述的划分方式S划分得到的子节点中是否存在至少一个子节点B的亮度块为4x4的亮度块(判断节点A的宽、高，和/或划分方式，和/或节点B的宽和高是否满足所述情况一中的条件中的至少一个)。
如果节点A的尺寸(宽、高)，和/或划分方式S满足情况一中的至少一个条件，则限制节点A覆盖区域内所有的编码单元均使用帧内预测。否则，判断节点A按照所述的划分方式S划分得到的子节点中是否存在至少一个子节点B的色度块为小块(判断节点A的尺寸，和/或划分方式S，和/或节点B的宽和高是否满足情况二中的至少一个条件，则执行步骤3至步骤6。
具体的，节点A的至少一个子节点B的色度块为小块的判断方法分为以下两种情况。
情况一：
满足以下预设条件一中的一个或者多个，则节点A按照划分方式S划分会得到4x4的亮度块：
1)节点A包含M1个像素且节点A的划分方式为四叉树划分，例如M1为64；
2)节点A包含M2个像素且节点A的划分方式为三叉树划分，例如M2为64；
3)节点A包含M3个像素且节点A的划分方式为二叉树划分，例如M3为32；
4)节点A的宽等于第二阈值的4倍、高等于第二阈值且节点A的划分方式为竖直三叉树划分；
5)节点A的宽等于第二阈值、高等于第二阈值的4倍且节点A的划分方式为水平三叉树划分；
6)节点A的宽等于第二阈值的2倍、高等于第二阈值且当前节点的划分方式为竖直二分；
7)节点A的高等于第二阈值的2倍、宽等于第二阈值且当前节点的划分方式为水平二分；
8)节点A的宽或/和高为第二阈值的2倍且节点A的划分方式为四叉树划分。
所述尺寸可以是节点A对应图像区域的宽和高、或者节点A对应图像区域所包含的亮度像素个数、或者节点A对应图像区域的面积。
通常，当前节点的宽为当前节点对应亮度块的宽，当前节点的高为当前节点对应亮度块的高。在具体的实现方式中，例如第二阈值可以为4。
情况二：
1)如果节点A的至少一个子节点B的色度块为2x4、或4x2大小；
2)如果节点A的至少一个子节点B的色度块的宽或高为2；
3)如果节点A包含128个亮度像素且节点A使用三叉树划分，或者如果节点A包含64个亮度像素且节点A使用二叉树划分或者四叉树划分或者三叉树划分；
4)如果节点A包含256个亮度像素且节点使用三叉树划分或者四叉树划分，或者如果节点A包含128个亮度像素且节点使用二叉树划分；
5)如果节点A包含N1个亮度像素且节点A使用三叉树划分，N1为64、128或者256。
6)如果节点A包含N2个亮度像素且节点A使用四叉树划分，N2为64或者256。
7)如果节点A包含N3个亮度像素且节点A使用二叉树划分，N3为64、128或者256。
需要说明的是，节点A包含128个亮度像素点也可以描述为当前节点的面积为128，或者节点A的宽和高的乘积为128，在此不作赘述。
步骤3：与上述第一种视频解码方法的步骤3相同。
步骤4：根据节点A覆盖区域的编码单元使用的预测模式，决定节点A的色度块和亮度块的划分方式。
如果节点A覆盖区域的编码单元均使用帧间预测模式，则节点A的亮度块和色度块按照所述划分方式S划分，得到节点A或/和节点A覆盖的区域内的子节点。其中，如果按照节点A或/和节点A覆盖的区域内的子节点的划分方式会产生4×4的亮度块，则该子节点的划分方式不被允许或者该子节点不能继续划分。例如，如果节点A的尺寸为8x8且使用水平二叉树(或者竖直二叉树)划分产生两个8x4(或两个4x8)的节点，8x4(或4x8)的节点继续划分会产生4x4的块，因此，此时8x4(或4x8)的节点不能继续划分。
如果节点A覆盖区域的编码单元均使用帧内预测模式时，实施方法可以使用上述第一种、第二种、第三种视频解码方法，在此不做赘述。例如，节点A的亮度块划分，色度块不划分。
步骤5：解析节点A划分得到的CU的预测块和残差信息。
同上述第一种视频解码方法的步骤5，在此不做赘述。
步骤6：解码各CU，得到节点A对应的图像块的重建信号
可以按照上述第一种视频解码方法的步骤6的方式实施，在此不再赘述。
本申请实施例提供的第五种视频解码方法，包括：
步骤1：与上述第一种视频解码方法的步骤1相同。
步骤2：判断节点A按照所述的划分方式S划分得到的子节点中是否存在至少一个子节点B的亮度块为4x4的亮度块(判断节点A的宽、高，和/或划分方式，和/或节点B的宽和高是否满足所述情况一中的条件中的至少一个)。如果节点A的尺寸(宽、高)，和/或划分方式S满足情况一中的至少一个条件，则限制节点A覆盖区域内所有的编码单元均使用帧内预测。
或者，判断节点A按照所述的划分方式S划分得到的子节点中是否存在至少一个子节点B的色度块为小块(判断节点A的尺寸，和/或划分方式S，和/或节点B的宽和高是否满足情况二中的至少一个条件，则执行步骤3至步骤6。
具体的，节点A的至少一个子节点B的色度块为小块的判断方法分为以下两种情况。
情况一：
满足以下预设条件一中的一个或者多个，则节点A按照划分方式S划分会得到4x4的亮度块：
1)节点A包含M1个像素且节点A的划分方式为四叉树划分，例如M1为64；
2)节点A包含M2个像素且节点A的划分方式为三叉树划分，例如M2为64；
3)节点A包含M3个像素且节点A的划分方式为二叉树划分，例如M3为32；
4)节点A的宽等于第二阈值的4倍、高等于第二阈值且节点A的划分方式为竖直三叉树划分；
5)节点A的宽等于第二阈值、高等于第二阈值的4倍且节点A的划分方式为水平三叉树划分；
6)节点A的宽等于第二阈值的2倍、高等于第二阈值且当前节点的划分方式为竖直二分；
7)节点A的高等于第二阈值的2倍、宽等于第二阈值且当前节点的划分方式为水平二分；
8)节点A的宽或/和高为第二阈值的2倍且节点A的划分方式为四叉树划分。
所述尺寸可以是节点A对应图像区域的宽和高、或者节点A对应图像区域所包含的亮度像素个数、或者节点A对应图像区域的面积。
通常，当前节点的宽为当前节点对应亮度块的宽，当前节点的高为当前节点对应亮度块的高。在具体的实现方式中，例如第二阈值可以为4。
情况二：
1)如果节点A的至少一个子节点B的色度块为2x4、或4x2大小；
2)如果节点A的至少一个子节点B的色度块的宽或高为2；
3)如果节点A包含128个亮度像素且节点A使用三叉树划分，或者如果节点A 包含64个亮度像素且节点A使用二叉树划分或者四叉树划分或者三叉树划分；
4)如果节点A包含256个亮度像素且节点使用三叉树划分或者四叉树划分，或者如果节点A包含128个亮度像素且节点使用二叉树划分；
5)如果节点A包含N1个亮度像素且节点A使用三叉树划分，N1为64、128或者256。
6)如果节点A包含N2个亮度像素且节点A使用四叉树划分，N2为64或者256。
7)如果节点A包含N3个亮度像素且节点A使用二叉树划分，N3为64、128或者256。
需要说明的是，节点A包含128个亮度像素点也可以描述为当前节点的面积为128，或者节点A的宽和高的乘积为128，在此不作赘述。
步骤3：与上述第一种视频解码方法的步骤3相同。
步骤4：根据节点A覆盖区域的编码单元使用的预测模式，决定节点A的色度块和亮度块的划分方式。
如果节点A覆盖区域的编码单元均使用帧间预测模式，则节点A的亮度块和色度块按照所述划分方式S划分，得到节点A或/和节点A覆盖的区域内的子节点。其中，如果按照节点A或/和节点A覆盖的区域内的子节点的划分方式会产生4×4的亮度块，则该子节点的划分方式不被允许或者该子节点不能继续划分。例如，如果节点A的尺寸为8x8且使用水平二叉树(或者竖直二叉树)划分产生两个8x4(或两个4x8)的节点，8x4(或4x8)的节点继续划分会产生4x4的块，因此，此时8x4(或4x8)的节点不能继续划分。
如果节点A覆盖区域的编码单元均使用帧内预测模式时，实施方法可以使用上述第一种、第二种、第三种视频解码方法，在此不做赘述。例如，节点A的亮度块划分，色度块不划分。
步骤5：解析节点A划分得到的CU的预测块和残差信息。
同上述第一种视频解码方法的步骤5，在此不做赘述。
步骤6：解码各CU，得到节点A对应的图像块的重建信号
可以按照上述第一种视频解码方法的步骤6的方式实施，在此不再赘述。
在一些实施例中，如果当前区域被划分一次将产生4x4亮度块(例如64亮度像素使用QT划分，或128亮度像素使用TT划分)，则当前区域默认为限制只能使用Intra模式。
否则，传输一个flag指示当前区域只能使用inter模式或者只能使用intra模式；
如果当前区域限制只能使用inter模式，则亮度和色度一起划分，其中如果当前区域中的节点划分产生4x4的亮度块，则这种划分不被允许。例如当前节点为8x8且使用HBT(或VBT)划分，产生两个8x4的节点，则这些节点继续划分将产生4x4CU，所以这些8x4节点不能继续划分。
如果区域限制只能使用Intra模式，和实施例一中的实施方式相同(即亮度划分，色度不划分)。
本申请技术方案带来的有益效果
本申请实施例提出了一种块划分方法，避免出现面积较小的色度块使用帧内预测模式，便于硬件的流水处理，及解码器的实现，同时在帧间预测中，可以跳过一些预测模式的语法元素的解析过程，从而减小编码复杂度。
解决了系数编码问题，减小编码复杂度。
该块划分方法可以如下：
解析节点A的划分方式
判断节点A按照所述的划分方式S划分后是否会得到至少一个子节点B的色度块为小块。(判断节点A的宽、高，和/或划分方式，和/或节点B的宽和高是否满足上述条件中的至少一个)
如果判断为真，则限制节点A覆盖区域内所有的编码单元同为帧内预测模式或帧间预测模式。
决定节点A的色度块和亮度块是否继续划分。
其中，如果节点A覆盖区域内所有编码单元均使用帧内预测，则节点A的亮度块按照划分方式S继续划分，节点A的色度块不再划分。如果节点A覆盖区域内所有编码单元均使用帧间预测，将节点A的亮度块和色度块按照划分方式S继续划分为N个包含亮度块和色度块的编码树节点。
其中，节点A的亮度块按照划分方式S继续划分，节点A的色度块不再划分。色度变换块和色度编码块相同大小。
当节点A覆盖区域内所有编码单元均使用帧内预测时，色度预测块和色度编码块相同大小；当节点A覆盖区域内所有编码单元均使用帧间预测时，色度预测块划分为子块(子块小于色度编码块)，每个子块的运动矢量为子块对应的亮度区域中的运动矢量。
其中，节点A的亮度块按照划分方式S继续划分；节点A的色度块不再划分。色度编码块对应的色度变换块和色度编码块相同大小，色度预测块和色度编码块相同大小，色度CB的运动信息为色度CB对应的亮度区域中某个预设位置的运动信息。
本领域技术人员能够领会，结合本文公开描述的各种说明性逻辑框、模块和算法步骤所描述的功能可以硬件、软件、固件或其任何组合来实施。如果以软件来实施，那么各种说明性逻辑框、模块、和步骤描述的功能可作为一或多个指令或代码在计算机可读媒体上存储或传输，且由基于硬件的处理单元执行。计算机可读媒体可包含计算机可读存储媒体，其对应于有形媒体，例如数据存储媒体，或包括任何促进将计算机程序从一处传送到另一处的媒体(例如，根据通信协议)的通信媒体。以此方式，计算机可读媒体大体上可对应于(1)非暂时性的有形计算机可读存储媒体，或(2)通信媒体，例如信号或载波。数据存储媒体可为可由一或多个计算机或一或多个处理器存取以检索用于实施本申请中描述的技术的指令、代码和/或数据结构的任何可用媒体。计算机程序产品可包含计算机可读媒体。
作为实例而非限制，此类计算机可读存储媒体可包括RAM、ROM、EEPROM、CD-ROM或其它光盘存储装置、磁盘存储装置或其它磁性存储装置、快闪存储器或可 用来存储指令或数据结构的形式的所要程序代码并且可由计算机存取的任何其它媒体。并且，任何连接被恰当地称作计算机可读媒体。举例来说，如果使用同轴缆线、光纤缆线、双绞线、数字订户线(DSL)或例如红外线、无线电和微波等无线技术从网站、服务器或其它远程源传输指令，那么同轴缆线、光纤缆线、双绞线、DSL或例如红外线、无线电和微波等无线技术包含在媒体的定义中。但是，应理解，所述计算机可读存储媒体和数据存储媒体并不包括连接、载波、信号或其它暂时媒体，而是实际上针对于非暂时性有形存储媒体。如本文中所使用，磁盘和光盘包含压缩光盘(CD)、激光光盘、光学光盘、数字多功能光盘(DVD)和蓝光光盘，其中磁盘通常以磁性方式再现数据，而光盘利用激光以光学方式再现数据。以上各项的组合也应包含在计算机可读媒体的范围内。
可通过例如一或多个数字信号处理器(DSP)、通用微处理器、专用集成电路(ASIC)、现场可编程逻辑阵列(FPGA)或其它等效集成或离散逻辑电路等一或多个处理器来执行指令。因此，如本文中所使用的术语“处理器”可指前述结构或适合于实施本文中所描述的技术的任一其它结构中的任一者。另外，在一些方面中，本文中所描述的各种说明性逻辑框、模块、和步骤所描述的功能可以提供于经配置以用于编码和解码的专用硬件和/或软件模块内，或者并入在组合编解码器中。而且，所述技术可完全实施于一或多个电路或逻辑元件中。
本申请的技术可在各种各样的装置或设备中实施，包含无线手持机、集成电路(IC)或一组IC(例如，芯片组)。本申请中描述各种组件、模块或单元是为了强调用于执行所揭示的技术的装置的功能方面，但未必需要由不同硬件单元实现。实际上，如上文所描述，各种单元可结合合适的软件和/或固件组合在编码解码器硬件单元中，或者通过互操作硬件单元(包含如上文所描述的一或多个处理器)来提供。
在上述实施例中，对各个实施例的描述各有侧重，某个实施例中没有详述的部分，可以参见其他实施例的相关描述。
以上所述，仅为本申请示例性的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到的变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应该以权利要求的保护范围为准。

Claims (33)

  1. 一种图像预测方法，其特征在于，所述方法包括：
    获取当前节点的划分方式，所述当前节点为当前图像中的编码树单元(coding tree unit)中的图像块；
    根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足第一条件；
    在确定所述当前节点满足所述第一条件的情况下，对所有属于当前节点的编码块使用进行帧内预测，从而得到所有属于所述当前节点的编码块的预测值。
  2. 根据权利要求1所述的方法，其特征在于，在确定所述当前节点不满足所述第一条件的情况下，所述方法还包括：
    根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足第二条件；
    在确定所述当前节点满足所述第二条件的情况下，对所有属于当前节点的编码块使用相同的预测方式进行预测，从而得到所有属于所述当前节点的编码块的预测值，所述预测方式为帧内预测或者帧间预测。
  3. 根据权利要求2所述的方法，其特征在于，所述根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足第二条件，包括：
    根据所述当前节点的划分方式，所述当前节点的尺寸和当前的采样格式(Chroma format)，判断所述当前节点是否满足第二条件。
  4. 根据权利要求2或3所述的方法，其特征在于，所述对所有属于当前节点的编码块使用相同的预测方式进行预测包括：
    解析所述当前节点的预测模式状态标识；
    在所述预测模式状态标识的值为第一值的情况下，对所有属于所述当前节点的编码块进行帧间预测；或者，在所述预测模式状态标识的值为第二值的情况下，对所有属于所述当前节点的的编码块进行帧内预测。
  5. 根据权利要求2至4任一项所述的方法，其特征在于，所述对所有属于所述当前节点的编码块进行帧间预测，包括：
    按照所述当前节点的划分方式对所述当前节点进行划分，得到所述当前节点的子节点；
    根据所述当前节点的子节点的尺寸，确定所述当前节点的子节点的不被允许的划分方式；
    根据所述当前节点的子节点的不被允许的划分方式，确定所述当前节点的子节点的快划分策略；
    根据所述当前节点的子节点的块划分策略，得到所述当前节点的子节点对应的编码块，并对所述对应的编码块使用帧间预测。
  6. 根据权利要求1至4任一项所述的方法，其特征在于，所述对所有属于所述当前节点的的编码块进行帧内预测，包括：
    按照所述划分方式对所述当前节点包括的亮度块进行划分，得到划分后的亮度块，对所述划分后的亮度块使用帧内预测，将所述当前节点包括的色度块作为色度编码块，对所述色度编码块使用帧内预测。
  7. 根据权利要求1至6任一项所述的方法，其特征在于，所述当前节点的尺寸根据所述当前节点对应的编码树节点的尺寸和用于得到所述当前节点的划分方式确定得到。
  8. 一种图像预测方法，其特征在于，所述方法包括：
    获取当前节点的划分方式，所述当前节点为当前图像中的编码树单元(coding tree unit)中的图像块；
    根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足预设条件；
    在确定所述当前节点满足所述预设条件的情况下，对所有属于当前节点的编码块使用相同的预测方式进行预测，从而得到所有属于所述当前节点的编码块的预测值，所述预测方式为帧内预测或者帧间预测。
  9. 根据权利要求8所述的方法，其特征在于，所述根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足预设条件，包括：
    根据所述当前节点的划分方式，所述当前节点的尺寸和当前的采样格式(Chroma format)，判断所述当前节点是否满足预设条件。
  10. 根据权利要求8或9所述的方法，其特征在于，所述对所有属于当前节点的编码块使用相同的预测方式进行预测包括：
    解析所述当前节点的预测模式状态标识；
    在所述预测模式状态标识的值为第一值的情况下，对所有属于所述当前节点的编码块进行帧间预测；或者，在所述预测模式状态标识的值为第二值的情况下，对所有属于所述当前节点的的编码块进行帧内预测。
  11. 根据权利要求8至10任一项所述的方法，其特征在于，所述对所有属于所述当前节点的编码块进行帧间预测，包括：
    按照所述当前节点的划分方式对所述当前节点进行划分，得到所述当前节点的子节点；
    根据所述当前节点的子节点的尺寸，确定所述当前节点的子节点的不被允许的划分方式；
    根据所述当前节点的子节点的不被允许的划分方式，确定所述当前节点的子节点的快划分策略；
    根据所述当前节点的子节点的块划分策略，得到所述当前节点的子节点对应的编码块，并对所述对应的编码块使用帧间预测。
  12. 根据权利要求8至11任一项所述的方法，其特征在于，所述当前节点的尺寸根据所述当前节点对应的编码树节点的尺寸和用于得到所述当前节点的划分方式确定得到。
  13. 一种图像预测方法，其特征在于，所述方法包括：
    根据当前节点的尺寸和所述当前节点的预测模式，确定所述当前节点不被允许的划分方式，所述当前节点为当前图像中的编码树单元(coding tree unit)中的图像块；
    根据所述当前节点的不被允许的划分方式，确定所述当前节点的快划分策略；
    根据所述当前节点的块划分策略，得到所述当前节点对应的编码块，并对所述对应的编码块使用帧间预测。
  14. 根据权利要求13所述的方法，其特征在于，所述根据当前节点的尺寸和所述当前节点的预测模式，确定所述当前节点不被允许的划分方式，包括：
    确定是否所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量是否为32；
    在确定所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量为32的情况下，确定二叉树划分为所述当前节点不被允许的划分方式。
  15. 根据权利要求13或14所述的方法，其特征在于，所述根据当前节点的尺寸和所述当前节点的预测模式，确定所述当前节点不被允许的划分方式，包括：
    确定是否所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量是否为64；
    在确定所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量为64的情况下，确定三叉树划分为所述当前节点不被允许的划分方式。
  16. 根据权利要求13至15任一项所述的方法，其特征在于，所述当前节点的尺寸根据所述当前节点对应的编码树节点的尺寸和用于得到所述当前节点的划分方式确定得到。
  17. 一种图像预测装置，其特征在于，包括：
    获取模块，用于获取当前节点的划分方式，所述当前节点为当前图像中的编码树单元(coding tree unit)中的图像块；
    判断模块，用于根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足第一条件；
    执行模块，用于在确定所述当前节点满足所述第一条件的情况下，对所有属于当前节点的编码块使用进行帧内预测，从而得到所有属于所述当前节点的编码块的预测值。
  18. 根据权利要求17所述的装置，其特征在于，所述判断模块还用于：在确定所述当前节点不满足所述第一条件的情况下，所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足第二条件；
    所述执行模块还用于：在确定所述当前节点满足所述第二条件的情况下，对所有属于当前节点的编码块使用相同的预测方式进行预测，从而得到所有属于所述当前节点的编码块的预测值，所述预测方式为帧内预测或者帧间预测。
  19. 根据权利要求18所述的装置，其特征在于，所述判断模块用于：根据所述当前节点的划分方式，所述当前节点的尺寸和当前的采样格式(Chroma format)，判断所述当前节点是否满足第二条件。
  20. 根据权利要求18或者19所述的装置，其特征在于，所述执行模块用于：
    解析所述当前节点的预测模式状态标识；
    在所述预测模式状态标识的值为第一值的情况下，对所有属于所述当前节点的编码块进行帧间预测；或者，在所述预测模式状态标识的值为第二值的情况下，对所有属于所述当前节点的编码块进行帧内预测。
  21. 根据权利要求18至20任一项所述的装置，其特征在于，所述执行模块用于：
    按照所述当前节点的划分方式对所述当前节点进行划分，得到所述当前节点的子节点；
    根据所述当前节点的子节点的尺寸，确定所述当前节点的子节点的不被允许的划分方式；
    根据所述当前节点的子节点的不被允许的划分方式，确定所述当前节点的子节点的快划分策略；
    根据所述当前节点的子节点的块划分策略，得到所述当前节点的子节点对应的编码块，并对所述对应的编码块使用帧间预测。
  22. 根据权利要求17至21任一项所述的装置，其特征在于，所述执行模块用于：
    按照所述划分方式对所述当前节点包括的亮度块进行划分，得到划分后的亮度块，对所述划分后的亮度块使用帧内预测，将所述当前节点包括的色度块作为色度编码块， 对所述色度编码块使用帧内预测。
  23. 一种图像预测装置，其特征在于，所述装置包括：
    获取模块，用于获取当前节点的划分方式，所述当前节点为当前图像中的编码树单元(coding tree unit)中的图像块；
    判断模块，用于根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点是否满足预设条件；
    执行模块，用于在确定所述当前节点满足所述预设条件的情况下，对所有属于当前节点的编码块使用相同的预测方式进行预测，从而得到所有属于所述当前节点的的编码块的预测值，所述预测方式为帧内预测或者帧间预测。
  24. 根据权利要求23所述的装置，其特征在于，所述判断模块，用于：
    根据所述当前节点的划分方式，所述当前节点的尺寸和当前的采样格式(Chroma format)，判断所述当前节点是否满足预设条件。
  25. 根据权利要求23或24所述的装置，其特征在于，所述执行模块用于：
    解析所述当前节点的预测模式状态标识；
    在所述预测模式状态标识的值为第一值的情况下，对所有属于所述当前节点的的编码块进行帧间预测；或者，在所述预测模式状态标识的值为第二值的情况下，对所有属于所述当前节点的编码块进行帧内预测。
  26. 根据权利要求23至25任一项所述的装置，其特征在于，所述执行模块用于：
    按照所述当前节点的划分方式对所述当前节点进行划分，得到所述当前节点的子节点；
    根据所述当前节点的子节点的尺寸，确定所述当前节点的子节点的不被允许的划分方式；
    根据所述当前节点的子节点的不被允许的划分方式，确定所述当前节点的子节点的快划分策略；
    根据所述当前节点的子节点的块划分策略，得到所述当前节点的子节点对应的编码块，并对所述对应的编码块使用帧间预测。
  27. 一种图像预测装置，其特征在于，所述装置包括：
    确定单元，用于根据当前节点的尺寸和所述当前节点的预测模式，确定所述当前节点不被允许的划分方式，所述当前节点为当前图像中的编码树单元(coding tree unit)中的图像块；
    所述确定单元，还用于根据所述当前节点的不被允许的划分方式，确定所述当前节点的快划分策略；
    预测单元，用于根据所述当前节点的块划分策略，得到所述当前节点对应的编码 块，并对所述对应的编码块使用帧间预测。
  28. 根据权利要求27所述的装置，其特征在于，所述确定单元，用于：
    确定是否所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量是否为32；
    在确定所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量为32的情况下，确定二叉树划分为所述当前节点不被允许的划分方式。
  29. 根据权利要求27或28所述的装置，其特征在于，所述确定单元，用于：
    确定是否所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量是否为64；
    在确定所有属于当前节点的编码块仅使用帧间模式进行预测，并且确定所述当前节点的亮度块的采样点数量为64的情况下，确定三叉树划分为所述当前节点不被允许的划分方式。
  30. 一种视频编码设备，其特征在于，包括处理器和用于存储所述处理器的可执行指令的存储器；其中所述处理器执行如权利要求1-16任一项所述的方法。
  31. 一种视频解码设备，其特征在于，包括处理器和用于存储所述处理器的可执行指令的存储器；其中所述处理器执行如权利要求1-16任一项所述的方法。
  32. 一种图像预测系统，其特征在于，包括：视频采集设备、如权利要求30所述的视频编码设备、如权利要求31所述的视频解码设备以及显示设备，所述视频编码设备分别与所述视频采集设备和所述视频解码设备连接，所述视频解码设备与所述显示设备连接。
  33. 一种计算机可读存储介质，其特征在于，其上存储有计算机程序，所述计算机程序被处理器执行以实现如权利要求1-16任一项所述的方法。
PCT/CN2020/070976 2019-01-08 2020-01-08 图像预测方法、装置、设备、系统及存储介质 WO2020143684A1 (zh)

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