WO2020143292A1 - 一种帧间预测方法及装置 - Google Patents

一种帧间预测方法及装置 Download PDF

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WO2020143292A1
WO2020143292A1 PCT/CN2019/116115 CN2019116115W WO2020143292A1 WO 2020143292 A1 WO2020143292 A1 WO 2020143292A1 CN 2019116115 W CN2019116115 W CN 2019116115W WO 2020143292 A1 WO2020143292 A1 WO 2020143292A1
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motion vector
candidate motion
candidate
block
sub
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PCT/CN2019/116115
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English (en)
French (fr)
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张娜
陈旭
郑建铧
林永兵
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华为技术有限公司
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Priority claimed from CN201910205089.8A external-priority patent/CN111432219B/zh
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Publication of WO2020143292A1 publication Critical patent/WO2020143292A1/zh

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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
    • H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding
    • H04N19/61—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding in combination with predictive coding

Definitions

  • Embodiments of the present application relate to the field of video encoding and decoding, and in particular, to an inter prediction method and device.
  • 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.
  • video compression coding is to use the correlation between the video sequence in the space domain, time domain and codeword to encode, so as to remove the redundancy between the video sequences as much as possible.
  • video compression coding is realized mainly through the steps of prediction (including intra prediction and inter prediction), transformation, quantization, and entropy coding according to the hybrid video coding framework of image blocks.
  • a sub-block fusion mode is introduced in the inter prediction mode, and the candidate list of the sub-block fusion mode includes the candidate motion corresponding to the advanced temporal motion vector prediction (advanced temporal motion vector prediction) (ATMVP) mode At least one of a vector, a candidate motion vector corresponding to the inherited control point motion vector prediction mode, and a candidate motion vector corresponding to the constructed control point motion prediction mode or a zero motion vector.
  • ATMVP advanced temporal motion vector prediction
  • Embodiments of the present application provide an inter prediction method and device, which can achieve compatibility of multiple prediction modes in a sub-block fusion mode, thereby improving decoding efficiency.
  • an embodiment of the present application provides an inter prediction method.
  • the method is applied to a decoding end.
  • the method may include: determining a sub-block fusion candidate list of an image block to be processed.
  • the sub-block fusion candidate list includes At least one candidate motion vector obtained by the candidate prediction mode, the plurality of candidate prediction modes includes a plan inter prediction mode; and the index information is parsed from the code stream, and the index information is used to indicate the target candidate motion in the sub-block fusion candidate list Vector; and based on the target candidate motion vector indicated by the index information, the predicted value of the image block to be processed is obtained.
  • the plurality of candidate prediction modes may include plan inter prediction mode, ATMVP mode, inherited control point motion vector prediction mode, constructed control point motion vector prediction mode or zero motion vector prediction mode. Two or more types, where the motion vector corresponding to the zero motion vector prediction mode is a zero motion vector.
  • the plan inter prediction mode is introduced in the candidate prediction mode, which makes the types of candidate motion vectors in the sub-block fusion mode more abundant.
  • the encoding end After the encoding end has finished encoding the image block to be processed, the encoding end also writes the index information of the target candidate motion vectors in the sub-block fusion candidate list into the code stream and passes it to the decoding end, and the decoding end parses the index information from the code stream. That is, the position of the target candidate motion vector in the sub-block fusion candidate list can be determined, so that the target candidate motion vector is determined in the constructed sub-block fusion candidate list.
  • the sub-block fusion candidate list includes one candidate motion vector corresponding to a prediction mode, that is, the sub-block fusion candidate list includes only one candidate motion vector, and the candidate motion vector is the target candidate motion vector, then encode The end does not need to encode the index of the target candidate motion vector, and the decoder does not need to decode the index of the target candidate motion vector. After the decoder determines the candidate motion vector corresponding to the prediction mode, it directly predicts the image to be processed.
  • the candidate prediction mode satisfies the affine prediction mode (including inherited control point motion Vector prediction mode and/or constructed control point motion vector prediction mode), ATMVP mode or plan inter prediction mode, the current codec block length and width are greater than or equal to 8, when this condition is met, you can The sub-block fusion mode is used to predict the image block to be processed.
  • sps_sbtmvp_enabled_flag 1 If sps_sbtmvp_enabled_flag is 1, add the second candidate motion vector corresponding to the ATMVP mode to the sub-block fusion candidate list.
  • sps_affine_enabled_falg If sps_affine_enabled_falg is 1, use the inherited control motion vector prediction mode to derive the candidate control point motion vector of the image block to be processed and add it to the sub-block fusion candidate list.
  • sps_affine_enabled_falg If sps_affine_enabled_falg is 1, use the constructed control point motion vector prediction mode to derive the candidate control point motion vector of the image block to be processed, and add it to the sub-block fusion candidate list.
  • sps_planar_enabled_flag 1 If sps_planar_enabled_flag is 1, the first candidate motion vector corresponding to the planned inter prediction mode is added to the subblock fusion candidate list.
  • the embodiment of the present application can also fill the sub-block fusion candidate list. For example, after the traversal process of the above prediction mode, when the length of the sub-block fusion candidate list is less than the maximum list length (MaxNumSubblockMergeCand), the sub-block fusion candidate The list is filled until the length of the sub-block fusion candidate list is equal to MaxNumSubblockMergeCand.
  • MaxNumSubblockMergeCand MaxNumSubblockMergeCand
  • padding may be performed by supplementing with zero motion vectors, or by combining the candidate motion vectors existing in the existing list and weighted average. It should be noted that other methods for obtaining the filling of the sub-block fusion candidate list may also be applicable to the present application, and will not be repeated here.
  • the at least one candidate motion vector respectively obtained by the multiple candidate prediction modes includes: a first candidate motion vector, a second candidate motion vector, a third candidate motion vector, a fourth candidate motion vector, or a fifth Candidate motion vectors, where the first candidate motion vector is obtained according to the plan inter prediction mode, the second candidate motion vector is obtained according to the ATMVP mode, the third candidate motion vector is obtained according to the inherited control point motion vector prediction mode, and the fourth candidate motion vector According to the constructed control point motion vector prediction mode, the fifth candidate motion vector is a zero motion vector.
  • the sub-block fusion candidate list includes one or more of the above-mentioned first candidate motion vector, second candidate motion vector, third candidate motion vector, fourth candidate motion vector or fifth candidate motion vector, Specifically, it is determined according to the rules for actually constructing the candidate motion vectors in the sub-block fusion candidate list.
  • the first candidate motion vector is arranged after the second candidate motion vector.
  • the first candidate motion vector is arranged after the third candidate motion vector.
  • the first candidate motion vector is arranged after the fourth candidate motion vector.
  • the arrangement order of different candidate motion vectors in the sub-block fusion candidate list is related to the traversal order of multiple candidate prediction modes in the process of determining the sub-block fusion candidate list.
  • the number of candidate motion vectors in the sub-block fusion candidate list is a positive integer less than or equal to 5.
  • the number of candidate motion vectors in the sub-block fusion candidate list may be 1, 2, 3, 4 or 5, specifically, the number of candidate motion vectors in the sub-block fusion candidate list is set at the encoding end and the decoding end .
  • the complexity of constructing the sub-block fusion candidate list can be reduced when the number of candidate motion vectors is small, the calculation amount for determining a target candidate motion vector from a plurality of candidate motion vectors can be reduced, so that the complexity of coding and decoding can be effectively reduced.
  • the codeword length of the index corresponding to the preceding candidate motion vector in the sub-block fusion list is less than or equal to the codeword length of the index corresponding to the following candidate motion vector.
  • a binary method can be used to represent the index information of the candidate motion vectors.
  • truncated Rice (TR) code is used to represent the index information.
  • the TR code maps each index value according to the maximum index value. To a different binary number, and the codeword length of the index corresponding to the preceding candidate motion vector in the sub-block fusion list is less than or equal to the codeword length of the index corresponding to the following candidate motion vector.
  • the prediction mode of the image block to be processed includes other prediction modes (such as merge mode or triangle PU mode, etc.) in addition to the above sub-block fusion mode, the sub-block fusion mode and The other prediction modes respectively predict the image blocks to be processed, obtain the prediction values of the image blocks to be processed corresponding to the different prediction modes, and determine the index of the target candidate motion vector in each mode, and determine the rate distortion according to the rate distortion optimization technology
  • the smallest prediction mode is the best prediction mode for the image block to be processed.
  • the index (merge_subblock_idx) of the target candidate motion vector in the sub-block fusion mode is written into the code stream and passed to the decoding end
  • the best prediction mode is other prediction In the merge mode, for example, the target candidate motion vector (ie merge_idx) in merge mode is written into the code stream and passed to the decoding end.
  • an embodiment of the present application provides an inter-frame prediction device.
  • the device includes a determination module, an analysis module, and a prediction module.
  • the determination module is used for a sub-block fusion candidate list of the image block to be processed, the sub-block fusion candidate list includes at least one candidate motion vector obtained according to multiple candidate prediction modes, and the multiple candidate prediction modes include planar inter prediction Mode;
  • the parsing module is used to parse the index information from the code stream, the index information is used to indicate the target candidate motion vector in the sub-block fusion candidate list;
  • the prediction module is used to obtain the target image based on the target candidate motion vector indicated by the index information The predicted value of the block.
  • the at least one candidate motion vector respectively obtained by the multiple candidate prediction modes includes: a first candidate motion vector, a second candidate motion vector, a third candidate motion vector, a fourth candidate motion vector, or a fifth Candidate motion vectors, where the first candidate motion vector is obtained according to the plan inter prediction mode, the second candidate motion vector is obtained according to the ATMVP mode, the third candidate motion vector is obtained according to the inherited control point motion vector prediction mode, and the fourth candidate motion vector According to the constructed control point motion prediction mode, the fifth candidate motion vector is a zero motion vector.
  • the first candidate motion vector is arranged after the second candidate motion vector.
  • the first candidate motion vector is arranged after the third candidate motion vector.
  • the first candidate motion vector is arranged after the fourth candidate motion vector.
  • the number of candidate motion vectors in the sub-block fusion candidate list is a positive integer less than or equal to 5.
  • the codeword length of the index corresponding to the preceding candidate motion vector in the sub-block fusion list is less than or equal to the codeword length of the index corresponding to the following candidate motion vector.
  • an embodiment of the present application provides an inter prediction method, which may include: determining a sub-block fusion mode candidate motion vector list of an image block to be processed, and the sub-block fusion mode candidate motion vector list candidate motion vectors Include a first candidate motion vector, which is obtained according to the plan inter prediction mode; and determine the first index of the image block to be processed, the first index is used to determine the candidate from the sub-block fusion mode candidate motion vector list A motion vector; and according to the candidate motion vector determined by the first index, a prediction value of the image block to be processed is obtained.
  • the candidate motion vectors in the sub-block fusion mode candidate motion vector list further include at least one of the second candidate motion vector, the third candidate motion vector, the fourth candidate motion vector, and the fifth candidate motion vector One, in which the second candidate motion vector is obtained according to the ATMVP mode, the third candidate motion vector is obtained according to the inherited control point motion vector prediction mode, the fourth candidate motion vector is obtained according to the constructed control point motion prediction mode, and the fifth candidate motion The vector is zero motion vector.
  • the candidate motion vectors in the candidate motion vector list of the sub-block fusion mode are arranged in a preset order, wherein the codeword length of the index corresponding to the candidate motion vectors arranged earlier is less than or equal to The codeword length of the index corresponding to the candidate motion vector.
  • the foregoing preset sequence includes: the first candidate motion vector is arranged after the second candidate motion vector.
  • the preset sequence includes: the first candidate motion vector is arranged after the third candidate motion vector.
  • the preset sequence includes: the first candidate motion vector is arranged after the fourth candidate motion vector.
  • the number of candidate motion vectors in the above-mentioned sub-block fusion mode candidate motion vector list is less than 5.
  • an embodiment of the present application provides an apparatus for inter prediction.
  • the apparatus includes: a list module for determining a sub-block fusion mode candidate motion vector list of an image block to be processed, in the sub-block fusion mode candidate motion vector list
  • the candidate motion vectors include the first candidate motion vector, which is obtained according to the plan inter prediction mode; the parsing module is used to determine the first index of the image block to be processed, and the first index is used to merge the mode from the sub-block
  • the candidate motion vector is determined in the candidate motion vector list; the prediction module is used to obtain the predicted value of the image block to be processed according to the candidate motion vector determined by the first index.
  • the candidate motion vectors in the sub-block fusion mode candidate motion vector list further include at least one of the second candidate motion vector, the third candidate motion vector, the fourth candidate motion vector, and the fifth candidate motion vector One, in which the second candidate motion vector is obtained according to the ATMVP mode, the third candidate motion vector is obtained according to the inherited control point motion vector prediction mode, the fourth candidate motion vector is obtained according to the constructed control point motion prediction mode, and the fifth candidate motion The vector is zero motion vector.
  • the candidate motion vectors in the candidate motion vector list of the sub-block fusion mode are arranged in a preset order, wherein the codeword length of the index corresponding to the candidate motion vectors arranged earlier is less than or equal to The codeword length of the index corresponding to the candidate motion vector.
  • the foregoing preset sequence includes: the first candidate motion vector is arranged after the second candidate motion vector.
  • the preset sequence includes: the first candidate motion vector is arranged after the third candidate motion vector.
  • the preset sequence includes: the first candidate motion vector is arranged after the fourth candidate motion vector.
  • the number of candidate motion vectors in the above-mentioned sub-block fusion mode candidate motion vector list is less than 5.
  • an embodiment of the present application provides a video decoding device, including: a nonvolatile memory and a processor coupled to each other, and the processor calls program codes stored in the memory to perform the first aspect or the second aspect Part or all of the steps of any method.
  • an embodiment of the present application provides a computer-readable storage medium that stores a program code, where the program code includes a method for performing any method of the first aspect or the second aspect Instructions for some or all steps.
  • an embodiment of the present application provides a computer program product, which, when the computer program product runs on a computer, causes the computer to perform some or all of the steps of the method of the first aspect or the second aspect.
  • the video decoding apparatus may determine a sub-block fusion candidate list of the image block to be processed, and the sub-block fusion candidate list includes at least one obtained according to multiple candidate prediction modes Candidate motion vectors, including multiple inter prediction modes in the plurality of candidate prediction modes; and parsing index information from the code stream, the index information is used to indicate target candidate motion vectors in the sub-block fusion candidate list; and based on the index information Indicated target candidate motion vector to obtain the predicted value of the image block to be processed.
  • the planar inter prediction mode is introduced in the sub-block fusion mode, which can realize the compatibility of multiple prediction modes in the sub-block fusion mode. To improve decoding efficiency.
  • FIG. 1A is a block diagram of an example of a video encoding and decoding system 10 for implementing an embodiment 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 diagram of control points for implementing image blocks to be processed according to an embodiment of the present application.
  • FIG. 7 is a schematic diagram of neighboring image blocks used to implement the current image block to be processed in the embodiment of the present application.
  • FIG. 8 is a schematic diagram 1 of neighboring image blocks for implementing control points according to an embodiment of the present application.
  • FIG. 9 is a schematic diagram 2 of adjacent image blocks for implementing a control point according to an embodiment of the present application.
  • FIG. 10 is a schematic flowchart 1 of a method for implementing an inter prediction method according to an embodiment of the present application
  • FIG. 11 is a second schematic flowchart of an inter prediction method for implementing an embodiment of the present application.
  • FIG. 12 is a schematic flowchart 3 of a method for implementing an inter prediction method according to an embodiment of the present application.
  • FIG. 13 is a fourth schematic flowchart of an inter prediction method for implementing an embodiment of the present application.
  • FIG. 14 is a schematic flowchart 5 of a method for implementing an inter prediction method according to an embodiment of the present application.
  • 15 is a schematic flowchart 6 of a method for implementing an inter prediction method according to an embodiment of the present application.
  • FIG. 16 is a structural block diagram of a video image decoding device according to 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, which are further divided into slices, and the slices are further divided into blocks, which may also be referred to as image blocks.
  • Video coding is performed in units of blocks.
  • the concept of blocks is further expanded.
  • MB macroblock
  • the macroblock can be further divided into multiple prediction blocks (partitions) that can be used for predictive coding.
  • HEVC high-efficiency video coding
  • the basic concepts such as coding unit (CU), prediction unit (PU) and transform unit (TU) are adopted.
  • CU coding unit
  • PU prediction unit
  • TU transform unit
  • a variety of block units are divided and described using a new tree-based structure.
  • 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.
  • 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 prediction block of the image block needs to be obtained, and for the same image block, the method of obtaining the prediction block of the image block when encoding the video stream and the image block when decoding the video stream
  • the method of predicting blocks is the same.
  • the method of determining the prediction block may include intra prediction and inter prediction.
  • An image block to be encoded or decoded (collectively referred to as a to-be-processed image block, which may be a CU) is taken as an example to illustrate the concept of inter prediction involved in the embodiments of the present application.
  • Inter-frame prediction when encoding the image block to be processed, it refers to the video frame (may be called the second video frame) adjacent to the video frame (which may be called the first video frame) where the image block to be processed is located Process the prediction information of the image block (that is, use the second video frame as the reference frame of the first video frame, and then determine the image block (which may be referred to as a reference block) that is most similar to the image block to be processed in the second video frame, and Use this reference block as prediction information of the image block to be processed).
  • inter prediction includes prediction modes such as forward prediction, backward prediction, and bidirectional prediction.
  • forward prediction refers to selecting a reference frame (which may be called a forward reference frame) from the set of forward reference frames to obtain the reference block of the image block to be processed, and using the pixel value of the reference block as the image block to be processed Pixel value
  • backward prediction refers to selecting a reference frame ((may be referred to as a backward reference frame)) from the set of backward reference frames to obtain the reference block of the image block to be processed, and the pixel value of the reference block As the pixel value of the image block to be processed
  • bidirectional prediction refers to selecting a reference frame from the forward reference frame set and the backward reference frame set to obtain the reference block of the image block to be processed, to obtain two reference blocks, and then according to The pixel values corresponding to the two reference blocks determine the pixel values of the image block to be processed.
  • the prediction method in the video codec may further include intra-frame prediction.
  • Intra-frame prediction refers to a prediction method that combines intra-frame prediction and inter-frame prediction.
  • the specific process of the above inter prediction method is: determining the prediction value of the image block to be processed (including all pixel values of the image block to be processed) according to the motion information of the image block to be processed, and the motion information of the image block to be processed includes a prediction direction indication Information, one or more motion vectors pointing to the reference block, and indication information of the video frame where the reference block is located (here, the video frame where the reference block is located is the reference frame), where the prediction direction indication information is used to indicate inter prediction Prediction direction, for example, the prediction direction includes forward prediction, backward prediction, or bidirectional prediction; the motion vector is used to indicate the displacement of the reference block relative to the image block to be processed; the indication information of the video frame where the reference block is located is used to indicate the reference block
  • the position in the video stream, that is, in which video frame the reference block is located, the indication information of the video frame where the reference block is located may be the index of the reference frame.
  • the motion vector is an important parameter in the inter prediction process, which represents the spatial displacement
  • the image block to be encoded in the current encoded image may be referred to as the image block to be processed, for example, in encoding, the image block currently being encoded; in decoding, the image currently being decoded Piece.
  • the decoded image block used to predict the image block to be processed in the reference image is called the reference block of the image block to be processed, that is, the reference block is an image block that provides a reference signal for the image block to be processed, where the reference signal represents The pixel value within the image block.
  • the block in the reference image that provides the prediction signal for the image block to be processed may be referred to as 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 image block to be processed. This image block block is called the prediction value of the image block to be processed.
  • 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 video image decoding method described in the embodiment of the present application is mainly used for intra prediction and inter prediction processes. This process exists in both the encoder 20 and the decoder 30.
  • the encoder 20 and the decoder 20 in the embodiment of the present application The decoder 30 may be a codec corresponding to a video standard protocol such as H.263, H.264, HEVV, MPEG-2, MPEG-4, VP8, VP9, or a next-generation video standard protocol (such as H.266, etc.) .
  • 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 HEVC/H.265. 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.
  • Embodiments according to some standards such as HEVC may use quantization parameters 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 coefficient to obtain the inverse quantization coefficient 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 (the image block 203 to be processed of the current picture 201) and the reconstructed picture data, for example, the same (current) from the buffer 216
  • 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) partitioning, or any combination thereof, and for performing predictions for each of block partitions or sub-blocks, for example, where mode selection includes selecting the tree structure of the divided image block 203 and selecting applications The prediction mode for each of the block partitions or sub-blocks.
  • QT quad-tree
  • BT binary-tree
  • TT triple-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 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 information for the video block of the current video slice by parsing the motion vector and other syntax elements, and use the prediction information 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 video image decoding method described in the embodiment below.
  • 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 vector of the control point of the to-be-processed image block derived from the motion vector of the adjacent affine coding block, or the derived motion vector of the sub-block of the to-be-processed image block may be further processed.
  • 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 device 400 includes: an inlet port 410 for receiving data and a receiver unit (Rx) 420, a processor for processing data, a logic unit or a central processing unit (CPU) 430, and a transmitter for transmitting data A unit (Tx) 440 and an 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 intra-frame 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 this application (in particular, the video image decoding method described in this 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 prediction unit (prediction unit, PU) may be called a to-be-processed image block, based on a translational motion model ( That is to say that the motion of all pixels in the image block to be processed is consistent, that is, all pixels have the same motion information), there are two inter prediction modes, which are called merge modes (also called merge modes, Among them, skip mode is regarded as a special case of fusion mode) and advanced motion vector prediction (advanced motion vector prediction (AMVP) mode).
  • merge modes also called merge modes, Among them, skip mode is regarded as a special case of fusion mode
  • advanced motion vector prediction advanced motion vector prediction (advanced motion vector prediction (AMVP) mode).
  • AMVP advanced motion vector prediction
  • sub-block prediction in this embodiment of the present application.
  • the process of the sub-block prediction mode includes: separately obtaining motion information of each sub-block in the image block to be processed, and then obtaining respective prediction values of each sub-block according to the respective motion information of each sub-block, thereby Get the predicted value of the image block to be processed), where the sub-block prediction modes include prediction modes based on non-translational motion models, such as affine merge mode (affine merge mode) and affine advanced motion vector prediction mode (affine AMVP mode) );
  • the sub-block prediction mode may also include an ATMVP mode, a plan inter prediction mode, and a sub-block fusion mode (sub-block based commercial mode), etc.
  • the sub-block prediction mode is used to further divide the image block to be processed into smaller image blocks (hereinafter referred to as sub-blocks), and perform motion compensation according to the motion information of all sub-blocks to obtain the image block to be processed The predicted value, thereby improving the prediction efficiency.
  • the process of performing inter prediction on the image block to be processed using the affine merge mode includes:
  • Step 1 Construct a candidate motion information list of the control points of the image block to be processed.
  • the candidate motion information list includes one or more candidate motion information multi-groups, and the candidate motion information multi-group includes candidate motion information of n1 control points of the image block to be processed, n1 is a positive integer greater than or equal to 2.
  • the image block to be processed is a CU
  • the control points of the image block to be processed may include the upper left vertex, the upper right vertex, the lower left vertex, and the lower right vertex control points of the image block to be processed, such as the control in FIG. 6 Points can be P1, P2, P3, and P4.
  • the above candidate motion information multi-group includes motion information of n control points.
  • the value of n may be 2, 3, 4, and in combination with FIG.
  • the two control points of the image block to be processed may be For any of the following situations: P1 and P2, P1 and P3, P1 and P4, P2 and P3, P2 and P4, P3 and P4; when the value of n is 3, the 3 control points of the image block to be processed can be For any of the following situations: P1, P2 and P3, P1, P2 and P4, P1, P3 and P4, P2, P3 and P4; when the value of n is 4, 4 of the image blocks to be processed are P1 , P2, P3 and P4.
  • the above-mentioned candidate motion information list for constructing the control point of the image block to be processed is to determine one or more candidate motion information multi-groups of the image block to be processed.
  • the inherited control point motion vector (inherited control point motion vectors) prediction mode and/or constructed control point motion vector prediction mode to construct a list of candidate motion information for control points.
  • the first type: adopting the inherited control point motion vector prediction mode to construct the candidate motion information list of the control point includes: determining the control of the image block to be processed according to the motion model of the adjacent reconstructed affine coding block of the image block to be processed Candidate motion information for points.
  • the above method for determining candidate motion information of a control point of an image block to be processed specifically includes: performing a first processing process on one or more adjacent image blocks of the image block to be processed in sequence according to a preset order until the candidate motion information of the control point
  • the number of candidate motion information multi-groups in the list is equal to the first preset value or until all adjacent image blocks are traversed.
  • the above first processing procedure is: according to the motion information of the n1 control points of the affine coding block where the i-th adjacent image block is located, determine the candidate motion information of the n1 control points of the image block to be processed, and A candidate motion information multi-group including candidate motion information of n1 control points of the image block to be processed is stored in the control point candidate motion information list, and n1 is a positive integer greater than or equal to 2.
  • one or more adjacent image blocks of the image block to be processed can be traversed to obtain the motion vector of the control point of the affine coding block from the affine coding block where the one or more adjacent image blocks are located, and According to the motion information of the n1 control points of the affine coding block, the motion model of the affine coding block is used to derive the candidate motion information of the n1 control points of the image block to be processed.
  • the motion information includes a motion vector.
  • the above-mentioned candidate motion information for determining n1 control points of an image block to be processed is a candidate motion vector for determining n1 control points of an image block to be processed, and in the following embodiment, the motion information Refers to the motion vector.
  • the five adjacent image blocks of the image block to be processed are A1, B1, C1, D1, and E1, respectively, which can be in the first preset order (for example, the order of A1 ⁇ B1 ⁇ C1 ⁇ D1 ⁇ E1 ) Traverse the adjacent image blocks of the image block to be processed, find the affine coding block where the adjacent image block is located, obtain the motion information of n1 control points of the affine coding block, and according to the motion model of the affine coding block (for example 4-parameter (corresponding to 2 control points) motion model or 6-parameter (corresponding to 3 control points) motion model) to determine the motion information of n1 control points of the image block to be processed.
  • the motion model of the affine coding block for example 4-parameter (corresponding to 2 control points) motion model or 6-parameter (corresponding to 3 control points) motion model
  • the control points of the image block to be processed are respectively denoted as M0, M1, M2, and M3, where the coordinates of M0 are ( x 0 ,y 0 ), the coordinates of M1 are (x 1 ,y 1 ), the coordinates of M2 are (x 2 ,y 2 ), and the coordinates of M3 are (x 4 ,y 4 ), where the adjacent image block A1 is located
  • the affine coding block is denoted as affine coding block 1
  • the control points of the affine coding block 1 are respectively denoted as N0, N1, N2, and N3, where the coordinates of N0 are (x 4 , y 4 ), and the motion vector of N0 Is (vx 4 ,vy 4 ), the coordinate of N1 is (x 5 ,y 5 ), the motion vector of N1 is (vx 5 ,vy 5 ), the coordinate of N2
  • a 4-parameter motion model can be used to determine the candidate motions of the two control points Information, specifically, the following formula (1) can be used to calculate the candidate motion vector of the control point M1, and the formula (2) can be used to calculate the candidate motion vector of the control point M2:
  • the candidate motion vector of the control point M1 is (vx 0 , vy 0 ).
  • the candidate motion vector of the control point M2 is (vx 1 ,vy 1 ).
  • the candidate motion vectors of the control points M1 and M2 of the image block to be processed are (vx 0 ,vy 0 ) and (vx 1 ,vy 1 ), that is, a candidate motion information binary is obtained, and the candidate motion information The binary group is stored in the candidate motion information list of the control point.
  • other candidate motion information of the control points M1 and M2 can also be obtained by using formula (1) and formula (2), and the candidate motion information binary is stored in the control Point in the candidate motion information list.
  • the three parameters can be determined according to the motion information of the control points N1, N2, and N3 of the above-mentioned affine coding block 1, using a 6-parameter motion model
  • the candidate motion information of the point specifically, the following formula (3) can be used to calculate the candidate motion vector of the control point M1, the formula (4) can be used to calculate the candidate motion vector of the control point M2, and the formula (5) can be used to calculate the control point M3
  • the candidate motion vector of the control point M1 is (vx 0 , vy 0 ).
  • the candidate motion vector of the control point M2 is (vx 1 ,vy 1 ).
  • the candidate motion vector of the control point M3 is (vx 2 , vy 2 ).
  • the motion vectors of the control points M1, M2, and M3 of the image block to be processed are (vx 0 ,vy 0 ), (vx 1 ,vy 1 ), and (vx 2 ,vy 2 ), that is, a candidate motion information three Tuple, and store the candidate motion information triplet in the candidate motion information list of the control point.
  • other candidate motion information of the control points M1, M2, and M3 can also be obtained by using formula (3), formula (4), and formula (5), and the candidate motion The information triplet is stored in the candidate motion information list of the control point.
  • the motion information of the n1 control points of the image block to be processed is determined according to the above method. Among them, if a neighboring image block among the neighboring image blocks A1, B1, C1, D1, and E1 is not available, skip the neighboring image block and continue according to the affine coding block where the next neighboring image block is located.
  • the motion information of the control points determines the motion information of n control points of the image block to be processed.
  • the image block (or sub-block) means that the image block (or sub-block) exists or has been reconstructed, that is, has been encoded or decoded, and its prediction mode is the inter prediction mode, otherwise It is considered that the image block (or sub-block) is not available, that is, the image block does not exist or the image block is not encoded or the prediction mode adopted by the adjacent image block is not an inter prediction mode.
  • the positions of the adjacent image blocks A1, B1, C1, D1, and E1 the traversal order of the adjacent image blocks (that is, the above-mentioned preset order), and the affine where the adjacent image blocks are located
  • the motion model of the coding block is not limited. In practical applications, adjacent image blocks at other positions, other traversal sequences, and other motion models may also be used.
  • the second type: using the constructed control point motion vector prediction mode, the candidate motion information list for constructing the control point includes:
  • adjacent coded blocks The motion information of the coded blocks adjacent to the control points of the image blocks to be processed (hereinafter referred to as adjacent coded blocks) are combined to serve as the motion vectors of the control points of the image blocks to be processed.
  • the motion vector prediction method of the constructed control point has the following two implementations.
  • the motion information of the adjacent coded blocks of the control points is determined as the candidate motion information of the control points of the image block to be processed.
  • the n1 The candidate motion information of each control point is combined to obtain an n1 tuple queue of candidate motion information of n1 control points of the image block to be processed.
  • control point of the image block to be processed Take the two control points of the image block to be processed as an example, such as the control point of the upper left vertex and the control point of the upper right vertex.
  • the control point of the upper left vertex of the image block to be processed is denoted as M0, and the control point M0
  • the adjacent image blocks are A2, B2, and C2, and A2, B2, and C2 are adjacent image blocks in the spatial domain of the control point M0.
  • the control point at the upper right vertex is denoted as M1, and the adjacent image blocks of the control point M1 are: D2, E2, and the adjacent image blocks on the spatial domain of the control point M1 of D2 and E2, the candidate motion information of the two control points of the image block to be processed includes the candidate motion information of the control point M0 and the candidate motion information of the control point M1 .
  • motion information of multiple sets of control points is obtained.
  • the motion information of the control points may be determined in a similar combination of control points.
  • the motion information of the image block is determined to be the motion information of the corresponding control point of the image block to be processed, and then the motion information of the control point is combined to obtain all combinations of the motion information of the n control points of the image block to be processed.
  • the adjacent image blocks of CP1 are C3, F3, and G3. These three adjacent image blocks are used to determine the motion information of the control point CP1.
  • the adjacent image blocks of the control point CP2 are D3 and E3. These two adjacent image blocks are used For determining the motion information of the control point CP2, the adjacent image blocks of the control point CP3 are A3 and B3.
  • These two adjacent image blocks are used to determine the motion information of the control point CP3, and the adjacent image blocks of the control point CP4 are T1. It is used to determine the motion information of the control point CP4, where A3, B3, C3, D3, E3, F3, and G3 are all adjacent image blocks in space, and T1 is adjacent image blocks in time domain.
  • the motion information of each adjacent image block can be acquired in the order of F3 ⁇ C3 ⁇ G3, and the detected motion information of the first available adjacent image block is used as the motion information of the control point M0.
  • the process of determining the motion information of the control point CP1 is as follows:
  • the motion information of the adjacent image block F3 is used as the motion information vcp1 of the control point CP1, and there is no need to judge whether the adjacent image block C3 and the adjacent image block G3 are available;
  • the motion information of the adjacent image block C3 is used as the motion information vcp1 of the control point CP1, and there is no need to judge whether the adjacent image block G3 is available;
  • the motion information of the adjacent image block G3 is used as the motion information vcp1 of the control point CP1;
  • the motion information of each adjacent image block can be acquired in the order of D3 ⁇ E3, and the detected motion information of the first available adjacent image block is used as the motion information vcp2 of the control point CP2.
  • the motion information of each adjacent image block can be acquired in the order of A3 ⁇ B3, and the detected motion information of the first available adjacent image block is used as the motion information vcp3 of the control point CP3.
  • the process of determining the motion information of the control point CP2 and the control point CP3 is similar to the process of determining the motion information of the control point CP1. For details, refer to the description of the determination of the motion information of the control point CP3, which will not be repeated here.
  • the motion information of the adjacent image block T1 is used as the motion information vcp4 of the control point CP4.
  • control points of the image block to be processed are combined to obtain a multivariate group of motion information of n control points.
  • the motion information of the two control points is constructed, then the motion information of the two control points CP1, CP2, CP3, and CP4 are combined, and the resulting control point motion information binary includes: (vcp1, vcp2), (vcp1, vcp3), (vcp1, vcp4), (vcp2, vcp3), (vcp2, vcp4), (vcp3, vcp4).
  • the motion information of the three control points is constructed, the motion information of the three control points in the above control points CP1, CP2, CP3, and CP4 are combined, and the resulting triad of motion information of the control points includes: (vcp1, vcp2, vcp3), (vcp1, vcp2, vcp4), (vcp2, vcp3, vcp4), (vcp1, vcp3, vcp4).
  • control point motion information is constructed, the motion information of the three control points in the above control points CP1, CP2, CP3, and CP4 are combined, and the resulting quaternion of control point motion information is: (vcp1, vcp2 , Vcp3, vcp4).
  • the candidate motion vector list of control points constructed by the above method is used to determine the motion information of the sub-blocks of the image block to be processed.
  • Step 2 Determine the target motion information of n1 control points of the image block to be processed from the candidate motion information list of the image block to be processed.
  • each candidate motion information multi-group in the candidate motion information list is used to adopt the above affine motion model (refer to the related Description)
  • Obtain the motion vector of each sub-block in the image block to be processed and then obtain the pixel value of the position in the reference frame pointed by the motion vector of each sub-block as its predicted value, and perform affine transformation motion compensation.
  • the encoding end calculates the average value of the difference between the original value and the predicted value of each pixel in the image block to be processed, and selects the candidate motion information multiple group corresponding to the smallest average value as the optimal candidate motion information combination.
  • the encoding end determines an optimal candidate motion information multi-group from the candidate motion information list, and uses the optimal candidate motion information multi-group as the target motion information of n1 control points of the image block to be processed, and then encodes The end transmits the index number (denoted as affine, Merge, index) in the candidate motion information list of the optimal candidate motion information multi-group to the decoding end.
  • the decoding end parses the code stream to obtain the optimal index of the candidate motion information multi-group in the candidate motion information list, so that the decoding end combines the optimal candidate motion information corresponding to the index in the candidate motion information list of n1 control points Multivariate groups serve as target candidate motion information for n2 control points.
  • Step 3 According to the target motion information of the n1 control points of the image block to be processed, adopt the affine motion model to determine the motion information of one or more sub-blocks of the image block to be processed.
  • commonly used non-translational motion models include a 4-parameter affine motion model or a 6-parameter affine motion model.
  • the 4-parameter affine motion model is:
  • (vx, vy) composed of vx and vy is the motion vector of the sub-block
  • (x, y) is the coordinates of the sub-block (specifically the coordinates relative to the upper left vertex pixel of the image block to be processed)
  • a 1 , a 2 , a 3 and a 4 are the four parameters of the affine motion model.
  • This parameter is related to the motion information of the two control points of the image block to be processed. Referring to FIG. 7, if the two control points are the control points M0 and M1, according to the motion information of the control point M1 and the control point M2, the motion information of the sub-block is:
  • (vx 0 , vy 0 ) is the motion vector of the control point M1
  • (vx 1 , vy 1 ) is the motion vector of the control point M2
  • w is the width of the image block to be processed.
  • the 6-parameter affine motion model is:
  • a 1 , a 2 , a 3 , a 4 , a 5 , and a 6 are the parameters of the affine transformation model. This parameter is related to the motion information of the target control point. If the above target control point includes three control points Respectively for the above control points M0, M1 and M3, according to the motion information of the control point M1, the control point M2 and the control point M3, the motion information of the target pixel in the first sub-block is:
  • (vx 0 , vy 0 ) is the motion vector of the control point M1
  • (vx 1 , vy 1 ) is the motion vector of the control point M2
  • (vx 2 , vy 2 ) is the motion vector of the control point M3.
  • Step 4 Determine the prediction value of the one or more sub-blocks according to the motion information of the one or more sub-blocks of the image block to be processed, and then obtain the prediction value of the image block to be processed.
  • each sub-block in the image block to be processed can be obtained by offsetting the sub-blocks of the reconstructed image block, each sub-block in the image block to be processed
  • the motion of the sub-block of the image block to be processed is determined in the reference frame of the image block to be processed
  • the affine AMVP mode is used to perform the inter prediction of the image block to be processed:
  • Step 1 Construct a candidate motion information list of the control points of the image block to be processed.
  • the method of constructing the candidate motion information list of the control point in the affine AMVP mode is similar to the method of constructing the candidate motion information list of the control point in the above affine merge mode.
  • the relevant description of the above embodiment please refer to the relevant description of the above embodiment. Repeat again.
  • Step 2 According to the candidate motion information list of the image block to be processed, determine the target motion information of n1 control points of the image block to be processed.
  • each candidate motion information multi-group in the candidate motion information list is used to adopt the above affine motion model (refer to the relevant Description)
  • Obtain the motion vector of each sub-block in the image block to be processed and then obtain the pixel value of the position in the reference frame pointed by the motion vector of each sub-block as its predicted value, and perform affine transformation motion compensation.
  • the encoding end calculates the average value of the difference between the original value and the predicted value of each pixel in the image block to be processed, and selects the candidate motion information multiple group corresponding to the smallest average value as the optimal candidate motion information combination.
  • the optimal multi-group of candidate motion information is used as the predicted value of the motion information of n1 control points of the image block to be processed, and the encoding end uses the motion vector (referred to as the motion vector of the control point) in the predicted value of the motion information of the control point (Predicted value) as a search starting point to perform motion search within a certain search range to obtain the motion vectors (CPMV) of the n1 control points, and obtain the predicted value of the motion vector of the control point and the motion vector of the control point.
  • the difference (control points, motion vectors, differences, CPMVD) between the encoder and the encoder end transmits the index of the optimal candidate motion information multi-group in the candidate motion information list and the CPMVD to the decoder end.
  • the decoding end parses the code stream to obtain the index and CPMVD of the optimal candidate motion information multi-group in the candidate motion information list, so that the decoding end combines the optimal candidate corresponding to the index in the candidate motion information list of n1 control points
  • the motion information multi-group is used as the candidate motion information prediction value of n1 control points, and the sum of the candidate motion information prediction value of n1 control points and CPMVD is used as the target motion information of n1 control points.
  • Step 3 According to the target motion information of the n1 control points of the image block to be processed, adopt the affine motion model to determine the motion information of one or more sub-blocks of the image block to be processed.
  • Step 4 Determine the prediction value of the one or more sub-blocks according to the motion information of the one or more sub-blocks of the image block to be processed, and then obtain the prediction value of the image block to be processed.
  • Step 3 and step 4 can refer to the description of step 3 and step 4 in the above affiliate mode, which will not be repeated here.
  • the process of performing inter-frame prediction on the image block to be processed in the ATMVP mode includes:
  • Step 1 Determine the motion information of the image block to be processed.
  • Step 2 According to the motion information of the image block to be processed and the position of the sub-block to be processed in the image block to be processed, determine the corresponding sub-block of the sub-block to be processed in the reference image;
  • Step 3 Determine the motion information of the sub-block to be processed according to the motion information of the corresponding sub-block.
  • the motion information of the corresponding sub-block is determined to determine the current motion information of the sub-block to be processed.
  • Step 4 Perform motion compensation prediction on the sub-block to be processed according to the motion information of the sub-block to be processed to obtain the prediction value of the sub-block to be processed, and obtain the prediction value of the image block to be processed based on the prediction values of all sub-blocks of the image block to be processed.
  • the average value is obtained and converted into the current motion information of each sub-block.
  • the sub-block motion vector P(x, y) is calculated using the horizontal interpolation motion vector and the vertical interpolation motion vector:
  • the interpolation motion vector in the horizontal direction and the interpolation motion vector in the vertical direction are calculated by using the motion vectors on the left, right, upper, and lower sides of the current sub-block:
  • L(-1, y) and R(W, y) represent the motion vectors at the left and right positions of the current sub-block
  • A(x, -1) and B(x, H) represent above and below the current sub-block Motion vector in side position.
  • the left motion vector L and the upper motion vector A are obtained from neighboring blocks in the spatial domain of the image block to be processed.
  • the motion vectors L(-1, y) and A(x, -1) of the image block at preset positions (-1, y) and (x, -1) are obtained according to the sub-block coordinates (x, y).
  • the right motion vector R(W, y) and the lower motion vector B(x, H) are extracted by the following methods:
  • All motion vectors used in the calculation are scaled to point to the first reference frame in a specific reference frame queue.
  • the sub-block fusion mode refers to a combination of several kinds of motion information to construct a candidate list.
  • the candidate list may be called a sub-block fusion candidate list (sub-block based candidate list).
  • the inherited control points may be used.
  • the motion vector prediction mode, the constructed control point motion vector prediction mode or the ATMVP mode can obtain candidate motion vectors obtained by two or more prediction modes to construct a sub-block fusion candidate list, and then predict the current image block.
  • the process of performing inter prediction on the image block to be processed using the sub-block fusion mode includes:
  • Step 1 Construct a sub-block fusion candidate list of the image block to be processed.
  • the construction process of the sub-block fusion candidate list is introduced.
  • the motion information obtained by the motion vector prediction method in the above ATMVP mode (the motion information is the motion information of the sub-block) and the inherited control point motion vector prediction mode to obtain the motion information (the motion information includes multiple candidate motion information multi-groups)
  • the motion vector prediction mode of the control point constructed above (the motion information includes multiple candidate motion information multi-groups) according to a preset order (for example, the motion vector corresponding to the ATMVP mode first, and the motion corresponding to the motion vector prediction mode of the control point inherited later Vectors, the sequence of motion vectors corresponding to the motion vector prediction mode of the reconstructed control point) is added (can be understood as stored) to the sub-block fusion candidate list.
  • the sub-block fusion candidate list is pruned and sorted according to specific rules (such as checking availability or removing duplicates, etc.), and it can be truncated or filled to a specific number.
  • the sub-block fusion candidate list includes The number of motion vectors of can be referred to as the maximum number of effective candidates of the sub-block fusion candidate list or the maximum list length of the sub-block fusion candidate list.
  • Step 2 Determine target candidate motion information from the sub-block fusion candidate list.
  • the encoding end use the motion information of each candidate in the sub-block fusion candidate list to obtain the predicted value of the pixel of the image block to be processed, and calculate the difference between the original value and the predicted value of each pixel in the image block to be processed The average value of, selects the candidate motion information corresponding to the smallest average value of the difference, and encodes the index number indicating the position of the candidate motion information in the candidate motion information list into the code stream and sends it to the decoding end.
  • the decoding end parse the index number, and determine the motion information of the control point (if it is the inherited control point motion vector prediction mode or the constructed control point motion vector prediction mode) or the sub-block fusion candidate list according to the index number
  • the motion information of the block if ATMVP or plan inter prediction mode is used as the target candidate motion information.
  • the inter prediction mode when used to decode the image block to be processed, the inter prediction mode may be signaled using syntax elements.
  • the current partial syntax structure of the inter prediction mode used for parsing the image block to be processed can be seen in Table 1. It should be noted that the grammatical elements in the grammatical structure can also be represented by other identifiers, which is not specifically limited in the embodiments of the present application.
  • the identifier used to indicate whether the image block to be processed adopts merge mode (ie, fusion mode or merge mode) for inter prediction can be represented by the syntax element merge_flag[x0][y0],
  • merge_flag[x0][y0] is used to indicate whether the merge mode is allowed for the inter prediction of the image block to be processed.
  • x0, y0 represent the coordinates of the image block to be processed in the image.
  • the identifier used to indicate whether the image block to be processed adopts the sub-block fusion mode for inter prediction can be represented by the syntax element merge_subblock_flag[x0][y0], in other words, the syntax element merge_subblock_flag[x0] [y0] Used to indicate whether the sub-block prediction mode is allowed for the inter prediction of the image block to be processed.
  • the type (slice_type) of the slice where the image block to be processed is P-type or B-type
  • the syntax element merge_idx[x0][y0] is used to indicate the index value of the merge candidate list in the above merge mode, that is, when the merge mode is selected (that is, when the merge mode is used to predict the image block to be processed), the target candidate The position of the motion vector in the merge candidate list.
  • the syntax element merge_subblock_idx[x0][y0] is used to indicate the index value of the sub-block fusion candidate list in the sub-block fusion mode, that is, to indicate when the sub-block fusion mode is selected (that is, to use the sub-block fusion mode to process the image block When performing prediction), the position of the target candidate motion vector in the sub-block fusion candidate list.
  • the syntax element inter_affine_flag[x0][y0] can be used to indicate whether the image block to be processed is predicted based on the affine AMVP mode when the image block to be processed is a P-type strip or a B-type strip.
  • the syntax element cu_affine_type_flag[x0][y0] can be used to indicate whether the image block to be processed uses a 6-parameter affine motion model for motion compensation when the image block to be processed is a P-type strip or a B-type strip.
  • cu_affine_type_flag[x0][y0] 0, indicating that the image block to be processed does not use the 6-parameter affine motion model for motion compensation, and only uses the 4-parameter affine motion model for motion compensation
  • cu_affine_type_flag[x0][y0] 1, indicating that the image block to be processed uses a 6-parameter affine motion model for motion compensation.
  • ae(v) represents the syntax elements that are coded using context-based adaptive arithmetic (cabac).
  • MotionModelIdc[x0][y0] motion model for motion compensation (motion model used for motion compensation) 0 translational motion 1 4-parameter affine motion (4-parameter affine motion) 2 6-parameter affine motion
  • MaxNumMergeCand MaxNumSubblockMergeCand
  • MaxNumSubblockMergeCand are used to indicate the maximum list length, indicating the maximum length of the constructed candidate motion vector list
  • inter_pred_idc[x0][y0] is used to indicate the prediction direction
  • PRED_L1 is used to indicate the backward prediction
  • num_ref_idx_l0_active_minus1 is used to indicate the front
  • the number of reference frames in the reference frame list ref_idx_l0[x0][y0] is used to indicate the forward reference frame index value of the image block to be processed
  • mvd_coding(x0,y0,0,0) is used to indicate the first motion vector Poor
  • mvp_l0_flag[x0][y0] is used to indicate the forward MVP candidate list index value
  • PRED_L0 is used to indicate the forward prediction
  • num_ref_idx_l1_active_minus1 is
  • MotionModelIdc[x][y] inter_affine_flag[x0][y0]+cu_affine_type_flag[x0][y0]
  • Step 3 Obtain the prediction value of one or more sub-blocks of the image block to be processed according to the target candidate motion information, and then obtain the prediction value of the image block to be processed.
  • the motion information of one or more sub-blocks is determined according to the affine motion model in the above affine merge mode, and based on the motion information of one or more sub-blocks, a Or the prediction value of multiple sub-blocks, and then the prediction value of the image block to be processed. If the target candidate motion information is the motion information of the sub-block, the prediction value of the sub-block is obtained based on the motion information of the sub-block, and then the prediction value of the image block to be processed is obtained.
  • Embodiments of the present application provide an inter prediction method and device, which can apply a sub-block fusion mode to an inter prediction method, and can achieve compatibility of multiple prediction modes in the sub-block fusion mode, thereby improving decoding efficiency.
  • the method and the device are based on the same inventive concept. Since the principles of the method and the device to solve the problem are similar, the implementation of the device and the method can be referred to each other, and the repetition is not repeated here.
  • the following is a detailed description of the inter prediction method provided in the embodiments of the present application from the perspective of the decoding end based on the above introduction to the multiple prediction modes in the inter prediction mode and the accompanying drawings, which may be specifically executed by the decoder 30 or decoded
  • the entropy decoding unit and the prediction processing unit in the processor are implemented by the processor, or executed by the processor.
  • the inter prediction method provided by the embodiment of the present application may include:
  • the sub-block fusion candidate list includes at least one candidate motion vector obtained according to a plurality of candidate prediction modes, and the plurality of candidate prediction modes include a plan inter prediction mode.
  • the plurality of candidate prediction modes may include plan inter prediction mode, ATMVP mode, inherited control point motion vector prediction mode, constructed control point motion vector prediction mode or zero motion vector prediction mode. Two or more types, where the motion vector corresponding to the zero motion vector prediction mode is a zero motion vector.
  • the at least one candidate motion vector obtained by the multiple candidate prediction modes includes: a first candidate motion vector, a second candidate motion vector, a third candidate motion vector, a fourth candidate motion vector, or a fifth candidate motion vector, where the first candidate The motion vector is obtained according to the plan inter prediction mode, the second candidate motion vector is obtained according to the ATMVP mode, the third candidate motion vector is obtained according to the inherited control point motion vector prediction mode, and the fourth candidate motion vector is obtained according to the constructed control point motion vector prediction mode It is obtained that the fifth candidate motion vector is a zero motion vector (that is, a motion vector corresponding to the zero motion vector prediction mode).
  • the sub-block fusion candidate list includes one or more of the above-mentioned first candidate motion vector, second candidate motion vector, third candidate motion vector, fourth candidate motion vector or fifth candidate motion vector, Specifically, it is determined according to the rules for actually constructing the candidate motion vectors in the sub-block fusion candidate list.
  • the number of candidate motion vectors in the determined sub-block fusion candidate list is a positive integer less than or equal to 5, for example, the number of candidate motion vectors may be 1, 2, 3, 4 or 5, specifically,
  • the number of candidate motion vectors in the sub-block fusion candidate list is set at the encoding end and the decoding end.
  • the complexity of constructing the sub-block fusion candidate list can be reduced when the number of candidate motion vectors is small, the calculation amount for determining a target candidate motion vector from a plurality of candidate motion vectors can be reduced, so that the complexity of coding and decoding can be effectively reduced.
  • the arrangement order of different candidate motion vectors included in the sub-block fusion candidate list may be different, and may specifically include the following situations:
  • the first candidate motion vector when the first candidate motion vector and the second candidate motion vector exist in the sub-block fusion candidate list, the first candidate motion vector is arranged after the second candidate motion vector.
  • the first candidate motion vector is arranged after the third candidate motion vector.
  • the first candidate motion vector when the first candidate motion vector and the fourth candidate motion vector exist in the sub-block fusion candidate list, the first candidate motion vector is arranged after the fourth candidate motion vector.
  • the arrangement order of different candidate motion vectors in the sub-block fusion candidate list is related to the traversal order of multiple candidate prediction modes in the process of determining the sub-block fusion candidate list, which will be specifically implemented in the following Examples are described in detail.
  • the decoding end completes the construction of the sub-block fusion candidate list, and the position of each candidate motion vector in the sub-block fusion candidate list in the sub-block fusion candidate list can be indicated by the index of the candidate motion vector , Each candidate motion vector has a corresponding index number.
  • the encoding end after the encoding end completes encoding of the image block to be processed, the encoding end also writes the index information of the target candidate motion vectors in the sub-block fusion candidate list into the code stream, and passes it to the decoding end. By parsing the index information, the position of the target candidate motion vector in the sub-block fusion candidate list can be determined, so that the target candidate motion vector can be determined in the constructed sub-block fusion candidate list.
  • the sub-block fusion candidate list is pruned and sorted according to specific rules, and it can be truncated or filled to a specific number.
  • sps_sbtmvp_enabled_flag 1 If sps_sbtmvp_enabled_flag is 1, add the second candidate motion vector corresponding to the ATMVP mode to the sub-block fusion candidate list.
  • sps_affine_enabled_falg is 1, use the inherited control motion vector prediction mode to derive the candidate control point motion vector of the image block to be processed and add it to the sub-block fusion candidate list.
  • sps_affine_enabled_falg uses the inherited control motion vector prediction mode to derive the candidate control point motion vector of the image block to be processed and add it to the sub-block fusion candidate list.
  • traverse the neighboring position blocks of the image block to be processed find the affine coding block where the position is located, and obtain the control point of the affine coding block The motion vector, and then through its motion model, derive the candidate control point motion vector of the image block to be processed.
  • the candidate control point motion vector is added to the sub-block fusion candidate list; otherwise, the motion vectors in the sub-block fusion candidate list are sequentially traversed to check the sub Is there the same motion vector as the candidate control point motion vector in the block fusion candidate list? If the same motion vector as the candidate control point motion vector does not exist in the sub-block fusion candidate list, the candidate control point motion vector is added to the sub-block fusion candidate list.
  • MaxNumSubblockMergeCand is a positive integer, such as 1, 2, 3, 4, 5, etc.
  • sps_affine_enabled_falg 1
  • use the constructed control point motion vector prediction mode to derive the candidate control point motion vector of the image block to be processed, and add the sub-block fusion candidate list, as shown in Figure 8, traverse the control in the preset order The combination of points to obtain a legal combination as a candidate control point motion vector.
  • a preset sequence is as follows: Affine(CP1,CP2,CP3)->Affine(CP1,CP2,CP4)->Affine(CP1,CP3,CP4)->Affine(CP2,CP3,CP4) ->Affine(CP1,CP2)->Affine(CP1,CP3), a total of 6 combinations.
  • sps_affine_type_flag 1
  • a preset sequence is as follows: Affine(CP1,CP2,CP3)->Affine(CP1,CP2,CP4)->Affine(CP1,CP3,CP4)->Affine(CP2, CP3,CP4)->Affine(CP1,CP2)->Affine(CP1,CP3), a total of 6 combinations.
  • the embodiment of the present application does not specifically limit the order in which six combinations are added to the sub-block fusion candidate list.
  • sps_affine_type_flag a preset sequence is as follows: Affine(CP1,CP2)->Affine(CP1,CP3), a total of 2 combinations.
  • the embodiment of the present application does not specifically limit the order in which the two combinations are added to the sub-block fusion candidate list.
  • the combination is considered unavailable. If a combination is available, determine the reference frame index of the combination (when two control points, select the reference frame index with the smallest reference frame index as the reference frame index of the combination; when greater than two control points, select the reference frame index with the most occurrences first, If there are as many reference frame indexes as the same number of occurrences, the smallest reference frame index is selected as the combined reference frame index), and the motion vectors of the control points are scaled. If the motion information of all the control points after scaling is the same , The combination is illegal.
  • the candidate control point motion vector is added to the sub-block fusion candidate list; otherwise, the motion information in the sub-block fusion candidate list is traversed sequentially, and the sub-block fusion candidate is checked Whether there is the same motion vector as the candidate control point motion vector in the list, if there is no motion vector same as the candidate control point motion vector in the sub-block fusion candidate list, the candidate control point motion vector is added to Sub-block fusion candidate list.
  • sps_planar_enabled_flag 1 If sps_planar_enabled_flag is 1, the first candidate motion vector corresponding to the planned inter prediction mode is added to the subblock fusion candidate list.
  • the embodiment of the present application may also fill in the sub-block fusion candidate list. For example, after the above traversal process, when the length of the sub-block fusion candidate list is less than the maximum list length (MaxNumSubblockMergeCand), the sub-block fusion The candidate list is filled until the length of the subblock fusion candidate list is equal to MaxNumSubblockMergeCand.
  • padding may be performed by supplementing with zero motion vectors, or by combining the candidate motion vectors existing in the existing list and weighted average. It should be noted that other methods for obtaining the filling of the sub-block fusion candidate list may also be applicable to the present application, and will not be repeated here.
  • the encoder when the sub-block fusion candidate list includes one candidate motion vector corresponding to a prediction mode, that is, the sub-block fusion candidate list includes only one candidate motion vector, and the candidate motion vector is Is the target candidate motion vector, the encoder does not need to encode the target candidate motion vector index, and the decoder does not need to decode the target candidate motion vector index. After the decoder determines the candidate motion vector corresponding to the prediction mode, it directly predicts the image to be processed .
  • a binary method can be used to represent the index information of the candidate motion vectors.
  • truncated Rice (TR) code is used to represent the index information.
  • the TR code maps each index value according to the maximum index value. To a different binary number, and the codeword length of the index corresponding to the preceding candidate motion vector in the sub-block fusion list is less than or equal to the codeword length of the index corresponding to the following candidate motion vector.
  • the maximum index value is 4, and each index value can be binarized according to Table 4.
  • the index codes corresponding to the online candidate motion vectors are arranged
  • the word length is less than or equal to the codeword length of the index corresponding to the candidate motion vectors that are arranged later.
  • the codeword length of index 1 is less than the codeword length of index 2
  • the codeword length of index 3 is equal to the codeword length of index 4.
  • the maximum index value is 2, and each index value can be binarized according to Table 5.
  • the execution order of S101 and S102 may not be limited.
  • the decoding end may execute S101 first, then execute S102, or may execute S102 first, then execute S101, or may execute S101 and S102 at the same time.
  • obtaining the prediction value of the image block to be processed according to the target candidate motion vector includes: determining the motion vector of a corresponding sub-block in the image block to be processed according to the target candidate motion vector, thereby obtaining the prediction value of the sub-block, and decoding
  • the terminal obtains the prediction values of all sub-blocks in the image block to be processed according to the above method, and then obtains the prediction values of the image block to be processed.
  • the method of determining the sub-block fusion candidate list of the image block to be processed by the decoding end is the same as the method of determining the sub-block fusion candidate list of the image block to be processed by the encoding end, that is, the decoding end determines
  • the sub-block fusion candidate list of is the same as the sub-block fusion candidate list determined by the corresponding encoder.
  • the encoding end determines the target candidate motion vector from the candidate motion vectors in the sub-block fusion candidate list.
  • the encoding end traverses the sub-block fusion candidate For each candidate motion vector in the list, perform motion compensation on the image block to be processed according to the candidate motion vector to obtain the predicted value (ie, reconstruction value) of the image block to be processed, and then according to the sum of the minimum absolute transformation differences and (sum of of absolute transformed differences) , SATD) criterion, the candidate motion vector corresponding to the smallest SATD is determined as the target candidate motion vector in the sub-block fusion mode (that is, the optimal candidate motion vector), thus, the image block to be processed is obtained according to the target motion vector
  • the prediction value is the prediction value of the image block to be processed in the sub-block fusion mode. If the prediction mode of the image block to be processed no longer contains other prediction modes (such as merge mode), the encoding end indexes the target candidate motion vector (ie merge_subblock_idx ) Write the code stream and pass it to the decoder.
  • the prediction mode of the image block to be processed includes other prediction modes (such as merge mode or triangle PU mode, etc.) in addition to the sub-block fusion mode
  • the sub-block fusion mode is adopted at the encoding end
  • other prediction modes to predict the image blocks to be processed respectively, to obtain the prediction values of the image blocks to be processed corresponding to the different prediction modes, and to determine the index of the target candidate motion vector in each mode, and to determine the rate according to the rate distortion optimization technology
  • the prediction mode with the least distortion is the best prediction mode for the image block to be processed.
  • the index (merge_subblock_idx) of the target candidate motion vector in the sub-block fusion mode is written into the code stream and passed to the decoding end
  • the best prediction mode is other prediction In the merge mode, for example, the target candidate motion vector (ie merge_idx) in merge mode is written into the code stream and passed to the decoding end.
  • the sub-block fusion candidate list includes at least one candidate motion vector obtained according to multiple candidate prediction modes, the Multiple candidate prediction modes include plan inter prediction modes; and parse index information from the code stream, the index information is used to indicate the target candidate motion vector in the sub-block fusion candidate list; and the target candidate motion indicated based on the index information Vector to obtain the predicted value of the image block to be processed.
  • the plan inter prediction mode is introduced in the candidate prediction mode, so that the candidate in the sub-block fusion mode
  • the types of motion vectors are more abundant, and a variety of prediction modes can be compatible in the sub-block fusion mode, thereby improving decoding efficiency.
  • the candidate prediction modes may include two or more of the multiple candidate prediction modes described in S101 above, and are determined
  • the types of candidate motion vectors in the sub-block fusion candidate list and the arrangement order of each candidate motion vector are related to the traversal order of multiple candidate prediction modes. Therefore, for the encoding end and the decoding end, The sub-block fusion candidate list is determined by various methods, and then the predicted image block is predicted to obtain the predicted value of the image block to be predicted.
  • candidate prediction modes include ATMVP, inherited control point motion vector prediction mode, planar inter prediction mode, constructed control point motion vector prediction mode and zero motion vector prediction mode, and the traversal of these candidate prediction modes
  • ATMVP ATMVP
  • inherited control point motion vector prediction mode planar inter prediction mode
  • constructed control point motion vector prediction mode zero motion vector prediction mode
  • traversal of these candidate prediction modes The order and the maximum number of candidate motion vectors available according to each prediction mode can be seen in Table 6.
  • the inter prediction method provided by the embodiment of the present application may include S201-S211:
  • the decoder after acquiring the second candidate motion vector, the decoder first performs an availability check on the second candidate motion vector, and if the second candidate motion vector is available, the second candidate motion vector is added to the sub-block fusion In the candidate list; if the second candidate motion vector is not available, it is discarded.
  • the second candidate motion vector is a candidate motion vector of a sub-block
  • the second candidate motion vector can refer to that during the process of acquiring the second candidate motion vector, the neighboring block of the current sub-block is available.
  • the sub-block fusion candidate list is an empty list, that is, the number of candidate motion vectors included in the sub-block fusion candidate list is 0.
  • the number of candidate motion vectors in the above sub-block fusion candidate list may also be referred to as the length of the sub-block fusion candidate list, and the above-mentioned preset number may also be referred to as the preset length of the sub-block fusion candidate list, combined with the above description of S101 It can be seen that the number of candidate motion vectors in the sub-block fusion candidate list is a positive integer less than or equal to 5.
  • the following S203 is executed, if the number of candidate motion vectors in the sub-block fusion candidate list reaches (ie is equal to) the preset number, Then, there is no need to add candidate motion vectors to the sub-block fusion candidate list, that is, after S201, the determination of the sub-block fusion candidate list has been completed.
  • the number of third candidate motion vectors that can be added to the sub-block fusion candidate list is at most 2.
  • the decoding end obtains the two third candidate motion vectors, after checking their availability and excluding duplicates, Add a specified number of third candidate motion vectors to the sub-block fusion candidate list, the specified number is determined according to a preset number, whether the second candidate motion vector is available, and the maximum number of third candidate motion vectors, and the need can be determined through S202 Several third candidate motion vectors are added to the sub-block fusion candidate list.
  • the preset number of candidate motion vectors in the sub-block fusion candidate list is 1, if the above second candidate motion vector is available, the candidate motion vectors in the sub-block fusion candidate list can be determined through S202 If the number is equal to the preset number, the number of candidate motion vectors in the sub-block fusion candidate list has reached the preset number, and the decoding end completes the determination of the sub-block fusion candidate list without adding candidate motion vectors corresponding to other candidate prediction modes to The sub-block fusion candidate list is listed; if the above second candidate motion vector is unavailable, it can be determined through S202 that the number of candidate motion vectors in the sub-block fusion candidate list is less than the preset number, and then it needs to be added to the sub-block fusion candidate list One candidate motion vector, and then the decoding end adds a third candidate motion vector to the sub-block fusion candidate list, thus completing the determination of the sub-block fusion candidate list.
  • the number of fourth candidate motion vectors that can be added to the sub-block fusion candidate list is at most 6. Specifically, in combination with the above S208, it can be determined that several fourths need to be stored in the sub-block fusion candidate list. Candidate motion vector.
  • the prediction result of the planned inter prediction mode of the image block to be processed is equivalent to the prediction result of the inherited control point motion vector prediction mode (the effect), so
  • the plan inter prediction mode may precede the inherited control point motion vector prediction mode (in the above S203, 0 third candidate motion vectors are added to the sub-block fusion candidate list); the plan inter prediction mode may be inherited After the control point motion vector prediction mode (adding 0 third candidate motion vectors to the subblock fusion candidate list in S207 above); the planar inter prediction mode can be between two inherited control point motion vector prediction modes, at this time, The sum of the number of third candidate motion vectors added to the sub-block fusion candidate list in S203 and S207 is less than or equal to 2.
  • candidate prediction modes include ATMVP, inherited control point motion vector prediction mode and plan inter prediction mode, and the traversal order of these several candidate prediction modes and the maximum number of candidate motion vectors available according to each prediction mode See Table 7 for the quantity.
  • the inter prediction method provided by the embodiment of the present application may include S301-S307:
  • the preset number of candidate motion vectors in the sub-block fusion candidate list is a positive integer less than 5, for example, the number of candidate motion vectors may be 1, 2, 3, or 4.
  • the following S303 is executed, if the number of candidate motion vectors in the sub-block fusion candidate list reaches (ie is equal to) the preset number, Then, there is no need to add candidate motion vectors to the sub-block fusion candidate list, that is, after S301, the determination of the sub-block fusion candidate list has been completed.
  • the number of third candidate motion vectors that can be added to the sub-block fusion candidate list is at most one, and the third candidate motion vector obtained at the decoding end is available, then the third candidate motion vector is added to Sub-block fusion candidate list.
  • candidate prediction modes include ATMVP, inherited control point motion vector prediction mode and plan inter prediction mode, and the traversal order of these several candidate prediction modes and the maximum number of candidate motion vectors available according to each prediction mode The quantity can be seen in Table 8.
  • the inter prediction method provided in the embodiments of the present application may include S401-S405:
  • S402. Determine whether the number of candidate motion vectors in the sub-block fusion candidate list is less than a preset number.
  • the preset number of candidate motion vectors in the sub-block fusion candidate list is a positive integer less than 5, for example, the number of candidate motion vectors may be 1, 2, 3, or 4.
  • the following S403 is executed, if the number of candidate motion vectors in the sub-block fusion candidate list reaches (ie is equal to) the preset number, Then, there is no need to add candidate motion vectors to the sub-block fusion candidate list, that is, after S401, the determination of the sub-block fusion candidate list has been completed.
  • the number of third candidate motion vectors that can be added to the sub-block fusion candidate list is at most one or two. After obtaining the third candidate motion vector at the decoding end, check its availability and remove duplicates ( If there is only one third candidate motion vector, there is no need to perform the action of eliminating duplicates), after adding a specified number of third candidate motion vectors to the sub-block fusion candidate list. Similarly, the specified number is determined according to the preset number, whether the second candidate motion vector is available, and the maximum number of third candidate motion vectors. It can be determined through S402 how many third candidate motions need to be added to the sub-block fusion candidate list Vector.
  • the following S405 is performed. If the number of candidate motion vectors in the sub-block fusion candidate list reaches (ie is equal to) the preset number, there is no need Add candidate motion vectors to the sub-block fusion candidate list, that is, after S403, the determination of the sub-block fusion candidate list has been completed.
  • candidate prediction modes include ATMVP, inherited control point motion vector prediction mode, constructed control point motion vector prediction mode, plan inter prediction mode, and zero motion vector prediction mode, and the traversal of these candidate prediction modes
  • ATMVP ATMVP
  • inherited control point motion vector prediction mode constructed control point motion vector prediction mode
  • plan inter prediction mode plan inter prediction mode
  • zero motion vector prediction mode the traversal of these candidate prediction modes
  • the inter prediction method provided by the embodiment of the present application may include S501-S511:
  • the preset number of candidate motion vectors in the sub-block fusion candidate list is a positive integer less than or equal to 5, for example, the number of candidate motion vectors may be 1, 2, 3, 4, or 5.
  • the following S503 is executed, if the number of candidate motion vectors in the sub-block fusion candidate list reaches (ie is equal to) the preset number, There is no need to add candidate motion vectors to the sub-block fusion candidate list, that is, after S501, the determination of the sub-block fusion candidate list has been completed.
  • the number of third candidate motion vectors that can be added to the sub-block fusion candidate list is at most 2.
  • a specified number of third candidate motion vectors are added to the sub-block fusion candidate list.
  • the specified number is determined according to the preset number, whether the second candidate motion vector is available, and the maximum number of third candidate motion vectors, and it can be determined through S502 how many third candidate motions need to be added to the sub-block fusion candidate list Vector.
  • the number of fourth candidate motion vectors that can be added to the sub-block fusion candidate list is at most 6.
  • the decoding end obtains six third candidate motion vectors, and after checking their availability, the sub-block fusion A specified number of fourth candidate motion vectors are added to the candidate list.
  • the specified number is determined according to the preset number, the number of added third candidate motion vectors, and the maximum number of fourth candidate motion vectors. It can be determined through S504 how many fourths need to be added to the sub-block fusion candidate list Candidate motion vector.
  • S507 Acquire a first candidate motion vector corresponding to the plan inter prediction mode, and if the first candidate motion vector is available, add the first candidate motion vector to the subblock fusion candidate list.
  • the total number of the third candidate motion vectors added to the sub-block fusion candidate list in S505 and the third candidate motion vectors added to the sub-block fusion candidate list in S509 is less than or Equal to 6.
  • candidate prediction modes include ATMVP, inherited control point motion vector prediction mode, constructed control point motion vector prediction mode and zero motion vector prediction mode, and the traversal order of these candidate prediction modes and according to each prediction
  • the maximum number of candidate motion vectors that can be obtained by the mode can be seen in Table 10.
  • the inter prediction method provided in this embodiment of the present application may include S601-S607:
  • S602 Determine whether the number of candidate motion vectors in the sub-block fusion candidate list is less than a preset number.
  • the preset number of candidate motion vectors in the sub-block fusion candidate list is a positive integer less than 5, for example, the number of candidate motion vectors may be 1, 2, 3, or 4.
  • the following S603 is executed, if the number of candidate motion vectors in the sub-block fusion candidate list reaches (ie is equal to) the preset number, Then, there is no need to add candidate motion vectors to the sub-block fusion candidate list, that is, after S601, the determination of the sub-block fusion candidate list has been completed.
  • S603 Acquire a third candidate motion vector corresponding to the inherited control point motion vector prediction mode, and if the third candidate motion vector is available and not repeated, add the third candidate motion vector to the sub-block fusion candidate list.
  • the number of third candidate motion vectors that can be added to the sub-block fusion candidate list is at most one or two. After obtaining the third candidate motion vector at the decoding end, check its availability and remove duplicates ( If there is only one third candidate motion vector, there is no need to perform the action of eliminating duplicates), after adding a specified number of third candidate motion vectors to the sub-block fusion candidate list. Similarly, the specified number is determined according to the preset number, whether the second candidate motion vector is available, and the maximum number of third candidate motion vectors. It can be determined through S402 how many third candidate motions need to be added to the sub-block fusion candidate list Vector.
  • S604 Determine whether the number of candidate motion vectors in the sub-block fusion candidate list is less than a preset number.
  • S605 Acquire a fourth candidate motion vector corresponding to the constructed control point motion vector prediction mode, and if the fourth candidate motion vector is available, add the fourth candidate motion vector to the sub-block fusion candidate list.
  • the sub-block fusion candidate list is determined by the above-mentioned different methods, and the prediction method for the image block to be processed is similar based on the sub-block fusion candidate list.
  • the prediction method for the image block to be processed is similar based on the sub-block fusion candidate list.
  • the decoding end may not need to construct a complete sub-block fusion candidate list, and the decoding end may learn the prediction mode adopted by the coding end in the encoding process and the order of the prediction modes adopted.
  • the order of prediction modes is the same as the order of candidate motion vectors in the sub-block fusion candidate list
  • the decoder can use the index of the target candidate motion vector and the prediction mode
  • the target candidate motion vectors are sequentially determined so that the image block to be processed is predicted based on the target candidate motion vector.
  • the decoding end knows that the sub-block fusion candidate list constructed by the encoding end includes 3 candidate motion vectors, and the prediction mode corresponding to the first candidate motion vector is the ATMVP mode, and the prediction mode corresponding to the second candidate motion vector is The mode is the inherited control point motion vector prediction mode.
  • the prediction mode corresponding to the third candidate motion vector is the plan inter prediction mode.
  • the index of the target candidate motion vector parsed by the decoder is 3. Then the decoder can know the corresponding index 3.
  • the prediction mode is plan inter prediction mode
  • the decoder directly obtains the candidate motion vector corresponding to plan inter prediction mode, and predicts the image block to be processed based on the candidate motion vector, so the decoder does not need to determine the subblock fusion candidate list
  • the first candidate motion vector and the second candidate motion vector in can significantly improve decoding efficiency.
  • an embodiment of the present application further provides a video image decoding device 1000.
  • the video image decoding device 1000 includes a determination module 1001, an analysis module 1002, and a prediction module 1003, where :
  • the determining module 1001 is used for a sub-block fusion candidate list of an image block to be processed, the sub-block fusion candidate list includes at least one candidate motion vector obtained according to a plurality of candidate prediction modes, and the plurality of candidate prediction modes includes a planar inter prediction mode ;
  • the parsing module 1002 is used to parse the index information from the code stream, the index information is used to indicate the target candidate motion vector in the sub-block fusion candidate list; the prediction module 1003 is used to obtain the target candidate motion vector based on the index information indicated above Process the predicted value of the image block.
  • At least one candidate motion vector obtained by each of the plurality of candidate prediction modes includes: a first candidate motion vector, a second candidate motion vector, a third candidate motion vector, a fourth candidate motion vector, or a fifth candidate motion vector, Among them, the first candidate motion vector is obtained according to the plan inter prediction mode, the second candidate motion vector is obtained according to the ATMVP mode, the third candidate motion vector is obtained according to the inherited control point motion vector prediction mode, and the fourth candidate motion vector is obtained according to the constructed control The point motion prediction mode is obtained, and the fifth candidate motion vector is a zero motion vector.
  • the first candidate motion vector and the second candidate motion vector exist in the sub-block fusion candidate list
  • the first candidate motion vector is arranged after the second candidate motion vector.
  • the first candidate motion vector is arranged after the third candidate motion vector.
  • the first candidate motion vector and the fourth candidate motion vector exist in the sub-block fusion candidate list
  • the first candidate motion vector is arranged after the fourth candidate motion vector.
  • the number of candidate motion vectors in the sub-block fusion candidate list is a positive integer less than or equal to 5.
  • the codeword length of the index corresponding to the preceding candidate motion vector in the sub-block fusion list is less than or equal to the codeword length of the index corresponding to the following candidate motion vector.
  • the computer program product includes one or more computer instructions.
  • the computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable devices.
  • the computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions can be from a website site, computer, server or data center via wired (Such as coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (such as infrared, wireless, microwave, etc.) to another website, computer, server or data center.
  • the computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device including one or more available media integrated servers, data centers, and the like.
  • the available media may be magnetic media (for example, floppy disk, magnetic disk, magnetic tape), optical media (for example, digital video disc (DVD)), or semiconductor media (for example, solid state drives (SSD)), etc. .
  • the disclosed system, device, and method may be implemented in other ways.
  • the device embodiments described above are only schematic.
  • the division of the module or unit is only a division of logical functions.
  • there may be another division manner for example, multiple units or components may be The combination can either be integrated into another system, or some features can be ignored, or not implemented.
  • the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical, mechanical, or other forms.
  • the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place or may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit.
  • the above integrated unit can be implemented in the form of hardware or software function unit.
  • the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it may be stored in a computer-readable storage medium.
  • the technical solution of the present application essentially or part of the contribution to the existing technology or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium , Including several instructions to enable a computer device (which may be a personal computer, server, or network device, etc.) or processor to perform all or part of the steps of the methods described in the embodiments of the present application.
  • the foregoing storage media include: flash memory, mobile hard disk, read-only memory, random access memory, magnetic disk or optical disk and other various media that can store program codes.

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Abstract

一种帧间预测方法及装置，涉及视频编解码领域，能够在子块融合模式中实现多种预测模式的兼容，从而提高解码效率。该方法包括：确定待处理图像块的子块融合候选列表，该子块融合候选列表包括根据多个候选预测模式获得的至少一个候选运动矢量，该多个候选预测模式中包括planar帧间预测模式（S101）；从码流中解析索引信息，该索引信息用于指示子块融合候选列表中的目标候选运动矢量（S102）；基于索引信息指示的目标候选运动矢量，得到待处理图像块的预测值（S103）。

Description

一种帧间预测方法及装置
本申请要求于2019年01月09日提交国家知识产权局、申请号为201910021819.9、申请名称为“一种帧间预测的方法和装置”的中国专利申请和要求于2019年03月18日提交国家知识产权局、申请号为201910205089.8、申请名称为“一种帧间预测方法及装置”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领域，尤其涉及一种帧间预测方法及装置。
背景技术
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。
视频压缩编码的基本原理是，利用视频序列在空域、时域和码字之间的相关性，进行编码，从而尽可能地去除视频序列之间的冗余。目前主要根据图像块的混合视频编码框架，通过预测(包括帧内预测和帧间预测)、变换、量化、熵编码等步骤来实现视频压缩编码。
在一种编/解码方法中，帧间预测模式中引入子块融合模式，该子块融合模式的候选列表中包括高级时域运动矢量预测(advanced temporal motion vector prediction，ATMVP)模式对应的候选运动矢量、继承的控制点运动矢量预测模式对应的候选运动矢量、构造的控制点运动预测模式对应的候选运动矢量或零运动矢量中的至少一个。目前，对于子块融合模式中可兼容的各种预测模式还在进一步的研究中。
发明内容
本申请实施例提供一种帧间预测方法及装置，能够在子块融合模式中实现多种预测模式的兼容，从而提高解码效率。
为达到上述目的，本申请实施例采用如下技术方案：
第一方面，本申请实施例提供一种帧间预测方法，该方法应用于解码端，该方法可以包括：确定待处理图像块的子块融合候选列表，该子块融合候选列表包括根据多个候选预测模式获得的至少一个候选运动矢量，该多个候选预测模式中包括planar帧间预测模式；并且从码流中解析索引信息，该索引信息用于指示子块融合候选列表中的目标候选运动矢量；以及基于该索引信息指示的目标候选运动矢量，得到待处理图像块的预测值。
本申请实施例中，上述多个候选预测模式可以包括planar帧间预测模式、ATMVP模式、继承的控制点的运动矢量预测模式、构造的控制点的运动矢量预测模式或零运动矢量预测模式中的两种或多种，其中，零运动矢量预测模式对应的运动矢量为零运动矢量。
上述在采用子块融合模式对待处理图像块进行解码时，在候选预测模式中引入了planar帧间预测模式，使得子块融合模式中的候选运动矢量的种类更加丰富。
编码端完成待处理图像块的编码之后，编码端将子块融合候选列表中的目标候选运动矢量的索引信息也写入码流，传递至解码端，解码端从码流中解析该索引信息，即可确定目标候选运动矢量在子块融合候选列表中的位置，从而在构建的子块融合候选列表中确定目标候选运动矢量。
应理解，当子块融合候选列表中包括一种预测模式对应的一个候选运动矢量时，即子块融合候选列表中仅包括一个候选运动矢量，该候选运动矢量即为目标候选运动矢量，则编码端无需编码目标候选运动矢量的索引，解码端也无需解码目标候选运动矢量的索引，解码端确定出该预测模式对应的候选运动矢量之后，直接对待处理图像进行预测。
结合解析待处理图像块所采用的帧间预测模式的部分语法结构可知，if((sps_affine_enabled_flagsps_sbtmvp_enabled_flagsps_planar_enabled_flag)&&cbWidth>＝8&&cbHeight>＝8)指的是候选预测模式满足仿射预测模式(包括继承的控制点运动矢量预测模式和\或构造的控制点运动矢量预测模式)、ATMVP模式或planar帧间预测模式中的任一种，当前编解码块的长和宽均大于等于8，当满足该条件时，可以采用子块融合模式对待处理图像块进行预测。
若sps_sbtmvp_enabled_flag为1，将ATMVP模式对应的第二候选运动矢量添加到子块融合候选列表。
若sps_affine_enabled_falg为1，利用继承的控制运动矢量预测模式，推导得到待处理图像块的候选的控制点运动矢量，添加到子块融合候选列表。
若sps_affine_enabled_falg为1，利用构造的控制点运动矢量预测模式，推导得到待处理图像块的候选的控制点运动矢量，并加入子块融合候选列表。
若sps_planar_enabled_flag为1，将planar帧间预测模式对应的第一候选运动矢量添加到子块融合候选列表。
本申请实施例还可以对子块融合候选列表进行填充，比如，经过上述预测模式的遍历过程后，此时子块融合候选列表的长度小于最大列表长度(MaxNumSubblockMergeCand)，则可以对子块融合候选列表进行填充，直到子块融合候选列表的长度等于MaxNumSubblockMergeCand。
本申请实施例中，可以通过补充零运动矢量的方法进行填充，或者通过将现有列表中已存在的候选运动矢量进行组合、加权平均的方法进行填充。需要说明的是，其他获得子块融合候选列表填充的方法也可适用于本申请，在此不做赘述。
一种可能的实现方式中，上述多个候选预测模式分别获得的至少一个候选运动矢量包括：第一候选运动矢量、第二候选运动矢量、第三候选运动矢量、第四候选运动矢量或第五候选运动矢量，其中，第一候选运动矢量根据planar帧间预测模式获得，第二候选运动矢量根据ATMVP模式获得，第三候选运动矢量根据继承的控制点运动矢量预测模式获得，第四候选运动矢量根据构造的控制点运动矢量预测模式获得，第五候选运动矢量为零运动矢量。
可以理解的是，子块融合候选列表中包括上述第一候选运动矢量、第二候选运动 矢量、第三候选运动矢量、第四候选运动矢量或第五候选运动矢量中的一种或者多种，具体根据实际构建该子块融合候选列表中的候选运动矢量的规则确定。
一种可能的实现方式中，当子块融合候选列表中存在第一候选运动矢量和第二候选运动矢量时，该第一候选运动矢量排列在第二候选运动矢量之后。
一种可能的实现方式中，当子块融合候选列表中存在第一候选运动矢量和第三候选运动矢量时，该第一候选运动矢量排列在第三候选运动矢量之后。
一种可能的实现方式中，当子块融合候选列表中存在第一候选运动矢量和第四候选运动矢量时，该第一候选运动矢量排列在第四候选运动矢量之后。
本申请实施例中，子块融合候选列表中不同的候选运动矢量的排列顺序与确定子块融合候选列表的过程中多种候选预测模式的遍历顺序有关。
一种可能的实现方式中，上述子块融合候选列表中的候选运动矢量的数量为小于或等于5的正整数。
该子块融合候选列表中的候选运动矢量的数量可以为1，2，3，4或5，具体的，该子块融合候选列表中的候选运动矢量的数量在编码端和解码端进行设定。
本申请实施例中，在不影响编解码效果或者对编解码效果影响很小的情况下，子块融合候选列表中的候选运动矢量的数量较少时，可以降低构建子块融合候选列表的复杂度，并且候选运动矢量的数量较少时，可以减少从多个候选运动矢量中确定目标候选运动矢量的计算量，从而可以有效地降低编解码的复杂度。
一种可能的实现方式中，上述子块融合列表中排列在先的候选运动矢量对应的索引的码字长度小于或等于排列在后的候选运动矢量对应的索引的码字长度。
可选的，可以采用二值化方法来表示候选运动矢量的索引信息，如采用截断莱斯编码(truncated rice，TR)码来表示索引信息，TR码是根据最大索引值，将各个索引值映射到不同的二进制数，并且子块融合列表中排列在先的候选运动矢量对应的索引的码字长度小于或等于排列在后的候选运动矢量对应的索引的码字长度。
一种可能的实现方式中，如果待处理图像块的预测模式除了上述子块融合模式之外，还包括其他预测模式(例如merge模式或triangle PU模式等)，那么编码端采用子块融合模式以及其他的预测模式分别对待处理图像块进行预测，得到不同的预测模式各自对应的待处理图像块的预测值，并且确定各种模式下的目标候选运动矢量的索引，根据率失真优化技术确定率失真最小的预测模式为待处理图像块的最佳预测模式。应理解，若该最佳预测模式为子块融合模式，则将子块融合模式下的目标候选运动矢量的索引(merge_subblock_idx)写入码流传递至解码端，若该最佳预测模式为其他预测模式，例如merge模式，则将merge模式下的目标候选运动矢量(即merge_idx)写入码流，传递至解码端。
第二方面，本申请实施例提供一种帧间预测装置，该装置包括确定模块、解析模块以及预测模块。其中，确定模块用于待处理图像块的子块融合候选列表，该子块融合候选列表包括根据多个候选预测模式获得的至少一个候选运动矢量，该多个候选预测模式中包括planar帧间预测模式；解析模块用于从码流中解析索引信息，该索引信息用于指示子块融合候选列表中的目标候选运动矢量；预测模块用于基于索引信息指示的目标候选运动矢量，得到待处理图像块的预测值。
一种可能的实现方式中，上述多个候选预测模式分别获得的至少一个候选运动矢量包括：第一候选运动矢量、第二候选运动矢量、第三候选运动矢量、第四候选运动矢量或第五候选运动矢量，其中，第一候选运动矢量根据planar帧间预测模式获得，第二候选运动矢量根据ATMVP模式获得，第三候选运动矢量根据继承的控制点运动矢量预测模式获得，第四候选运动矢量根据构造的控制点运动预测模式获得，第五候选运动矢量为零运动矢量。
一种可能的实现方式中，当子块融合候选列表中存在第一候选运动矢量和第二候选运动矢量时，该第一候选运动矢量排列在第二候选运动矢量之后。
一种可能的实现方式中，当子块融合候选列表中存在第一候选运动矢量和第三候选运动矢量时，该第一候选运动矢量排列在第三候选运动矢量之后。
一种可能的实现方式中，当子块融合候选列表中存在第一候选运动矢量和第四候选运动矢量时，第一候选运动矢量排列在第四候选运动矢量之后。
一种可能的实现方式中，子块融合候选列表中的候选运动矢量的数量为小于或等于5的正整数。
一种可能的实现方式中，子块融合列表中排列在先的候选运动矢量对应的索引的码字长度小于或等于排列在后的候选运动矢量对应的索引的码字长度。
第三方面，本申请实施例提供一种帧间预测方法，该方法可以包括：确定待处理图像块的子块融合模式候选运动矢量列表，该子块融合模式候选运动矢量列表中的候选运动矢量包括第一候选运动矢量，该第一候选运动矢量根据planar帧间预测模式获得；并且确定待处理图像块的第一索引，该第一索引用于从子块融合模式候选运动矢量列表中确定候选运动矢量；以及根据由第一索引确定的候选运动矢量，获得待处理图像块的预测值。
一种可能的实现方式中，上述子块融合模式候选运动矢量列表中的候选运动矢量还包括第二候选运动矢量、第三候选运动矢量、第四候选运动矢量和第五候选运动矢量中的至少一种，其中，第二候选运动矢量根据ATMVP模式获得，第三候选运动矢量根据继承的控制点运动矢量预测模式获得，第四候选运动矢量根据构造的控制点运动预测模式获得，第五候选运动矢量为零运动矢量。
一种可能的实现方式中，上述子块融合模式候选运动矢量列表中的候选运动矢量按照预设顺序排列，其中，排列在先的候选运动矢量对应的索引的码字长度小于或等于排列在后的候选运动矢量对应的索引的码字长度。
一种可能的实现方式中，上述预设顺序包括：第一候选运动矢量排列在第二候选运动矢量之后。
一种可能的实现方式中，上述预设顺序包括：第一候选运动矢量排列在第三候选运动矢量之后。
一种可能的实现方式中，上述预设顺序包括：第一候选运动矢量排列在第四候选运动矢量之后。
一种可能的实现方式中，上述子块融合模式候选运动矢量列表中的候选运动矢量的个数小于5。
第四方面，本申请实施例提供一种帧间预测的装置，该装置包括：列表模块用于 确定待处理图像块的子块融合模式候选运动矢量列表，该子块融合模式候选运动矢量列表中的候选运动矢量包括第一候选运动矢量，该第一候选运动矢量根据planar帧间预测模式获得；解析模块用于确定待处理图像块的第一索引，该第一索引用于从子块融合模式候选运动矢量列表中确定候选运动矢量；预测模块用于根据由第一索引确定的候选运动矢量，获得待处理图像块的预测值。
一种可能的实现方式中，上述子块融合模式候选运动矢量列表中的候选运动矢量还包括第二候选运动矢量、第三候选运动矢量、第四候选运动矢量和第五候选运动矢量中的至少一种，其中，第二候选运动矢量根据ATMVP模式获得，第三候选运动矢量根据继承的控制点运动矢量预测模式获得，第四候选运动矢量根据构造的控制点运动预测模式获得，第五候选运动矢量为零运动矢量。
一种可能的实现方式中，上述子块融合模式候选运动矢量列表中的候选运动矢量按照预设顺序排列，其中，排列在先的候选运动矢量对应的索引的码字长度小于或等于排列在后的候选运动矢量对应的索引的码字长度。
一种可能的实现方式中，上述预设顺序包括：第一候选运动矢量排列在第二候选运动矢量之后。
一种可能的实现方式中，上述预设顺序包括：第一候选运动矢量排列在第三候选运动矢量之后。
一种可能的实现方式中，上述预设顺序包括：第一候选运动矢量排列在第四候选运动矢量之后。
一种可能的实现方式中，上述子块融合模式候选运动矢量列表中的候选运动矢量的个数小于5。
第五方面，本申请实施例提供一种视频解码设备，包括：相互耦合的非易失性存储器和处理器，该处理器调用存储在存储器中的程序代码以执行上述第一方面或者第二方面的任意一种方法的部分或全部步骤。
第六方面，本申请实施例提供一种计算机可读存储介质，该计算机可读存储介质存储了程序代码，其中，该程序代码包括用于执行第一方面或者第二方面的任意一种方法的部分或全部步骤的指令。
第七方面，本申请实施例提供一种计算机程序产品，当该计算机程序产品在计算机上运行时，使得计算机执行第一方面或者第二方面的任意一种方法的部分或全部步骤。
应当理解的是，本申请的第二至第七方面技术方案及对应的可行实施方式所取得的有益效果可以参见上述对第一方面及其对应的可能实施方式的技术效果，此处不再赘述。
可以看到，本申请实施例提供的帧间预测方法及装置，视频解码装置可以确定待处理图像块的子块融合候选列表，该子块融合候选列表包括根据多个候选预测模式获得的至少一个候选运动矢量，该多个候选预测模式中包括planar帧间预测模式；并且从码流中解析索引信息，该索引信息用于指示子块融合候选列表中的目标候选运动矢量；以及基于该索引信息指示的目标候选运动矢量，得到待处理图像块的预测值，本申请实施例中，在子块融合模式中引入了planar帧间预测模式，能够在子块融合模式 中实现多种预测模式的兼容，从而提高解码效率。
附图说明
图1A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用于实现本申请实施例的待处理图像块的控制点的示意图；
图7是用于实现本申请实施例的当前待处理图像块的相邻图像块的示意图；
图8是用于实现本申请实施例的控制点的相邻图像块的示意图一；
图9是用于实现本申请实施例的控制点的相邻图像块的示意图二；
图10用于实现本申请实施例的帧间预测方法流程示意图一；
图11用于实现本申请实施例的帧间预测方法流程示意图二；
图12用于实现本申请实施例的帧间预测方法流程示意图三；
图13用于实现本申请实施例的帧间预测方法流程示意图四；
图14用于实现本申请实施例的帧间预测方法流程示意图五；
图15用于实现本申请实施例的帧间预测方法流程示意图六；
图16用于实现本申请实施例的视频图像解码装置的结构框图。
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。
本申请实施例所涉及的技术方案不仅可能应用于现有的视频编码标准中(如H.264、HEVC等标准)，还可能应用于未来的视频编码标准中(如H.266标准)。本申请的实施方式部分使用的术语仅用于对本申请的具体实施例进行解释，而非旨在限定本申请。下面先对本申请实施例可能涉及的一些概念及相关现有技术进行简单介绍。
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)，也可以称为图像块。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，在H.264标准中有宏块(macroblock，MB)，宏块可进一步划分成多个可用于预测编码的预测块(partition)。在高性能视频编码(high efficiency video coding，HEVC)标准中，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。
例如在HEVC中，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。
上述在编码视频流和解码视频流的过程中，均需要获取图像块的预测块，并且对于同一图像块，编码视频流时获取该图像块的预测块的方法与解码视频流时获取该图像块的预测块的方法相同。通常确定预测块的方法可以包括帧内预测和帧间预测。下面以待编码或者待解码的图像块(统一称为待处理图像块，该待处理图像块可以为一个CU)为例说明本申请实施例涉及到的帧间预测的概念。
帧间预测：指的是对待处理图像块编码时，根据与该待处理图像块所在的视频帧(可以称为第一视频帧)相邻的视频帧(可以称为第二视频帧)确定待处理图像块的预测信息(即将第二视频帧作为第一视频帧的参考帧，然后再在该第二视频帧中确定与待处理图像块最相似的图像块(可以称为参考块)，并将该参考块作为待处理图像块的预测信息)。具体的，帧间预测包括前向预测、后向预测和双向预测等预测模式。其中，前向预测指的是从前向参考帧集合中选择一个参考帧(可以称为前向参考帧)来获取待处理图像块的参考块，并将该参考块的像素值作为待处理图像块的像素值；后向预测指的是从后向参考帧集合中选择一个参考帧((可以称为后向参考帧))来 获取待处理图像块的参考块，并将该参考块的像素值作为待处理图像块的像素值；双向预测指的是从前向参考帧集合和后向参考帧集合中个选择一个参考帧来获取待处理图像块的参考块，得到两个参考块，然后再根据这两个参考块对应的像素值确定待处理图像块的像素值。
本申请实施例中，视频编解码中的预测方法还可以包括帧内帧间预测，帧内帧间预测指的是帧内预测与帧间预测相结合的预测方法。
上述帧间预测方法的具体过程为：根据待处理图像块的运动信息确定该待处理图像块的预测值(包括待处理图像块的所有像素值)，待处理图像块的运动信息包括预测方向指示信息、一个或者多个指向参考块的运动矢量以及参考块所在的视频帧(此处，参考块所在的视频帧即为参考帧)的指示信息，其中，预测方向指示信息用于指示帧间预测的预测方向，例如预测方向包括前向预测、后向预测或双向预测；运动矢量用于指示参考块相对于待处理图像块的位移；参考块所在的视频帧的指示信息用于指示参考块在视频流中的位置，即参考块位于哪个视频帧，参考块所在的视频帧的指示信息可以为参考帧的索引。运动矢量是帧间预测过程中的一个重要参数，其表示已重建的图像块相对于该待处理图像块的空间位移。
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待处理图像块，例如在编码中，指当前正在编码的图像块；在解码中，指当前正在解码的图像块。将参考图像中用于对待处理图像块进行预测的已解码的图像块称为待处理图像块的参考块，即参考块是为待处理图像块块提供参考信号的图像块，其中，参考信号表示图像块内的像素值。可将参考图像中为待处理图像块提供预测信号的块称为预测块，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，此最佳参考块将为待处理图像块提供预测，此图像块块称为待处理图像块的预测值。
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视频图像解码方法主要用于帧内预测和帧间预测过程，此过程在编码器20和解码器30均存在，本申请实施例中的编码器20和解码器30可以是例如H.263、H.264、HEVV、MPEG-2、MPEG-4、VP8、VP9等视频标准协议或者下一代视频标准协议(如H.266等)对应的编/解码器。
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HEVC/H.265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HEVC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的待处理图像块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)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。
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信息，并使用预测信息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视频图像解码方法。
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待处理图像块的控制点的运动矢量，或者推导得到的待处理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>＝2bitDepth-1)？(uy-2bitDepth):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 PCTCN2019116115-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和接收器单元(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，尤其是各种新的帧内帧间的方法。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视频图像解码方法)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：
首先对本申请实施例涉及到的帧间预测采用的相关技术进行描述。
不限于现有标准中的几种帧间预测模式，例如在HEVC(即H.265)标准中，对于预测单元(prediction unit，PU)，可以称为待处理图像块，基于平动运动模型(即认为待处理图像块中的所有像素点的运动一致，即所有像素点具有相同的运动信息)，存在两个帧间预测模式，分别称为融合(merge)模式(也可以称为合并模式，其中，跳过(skip)模式被视为融合模式的特殊情况)和先进的运动向量预测(advanced motion vector prediction，AMVP)模式。
然而，在现实世界中存在很多非平动运动的物体，如旋转的物体、在不同方向旋转的过山车、投放的烟花、电影中的一些特技动作，对于一个图像块而言，非平动运动也就是指图像块中像素点的运动并不完全一致，即不是所有的像素都有相同的运动特性。若采用当前编码标准中的基于平动运动模型的运动补偿技术，编码效率会受到很大的影响，因此，业界提出了多种基于子块的预测方法(本申请实施例中简称为子块预测模式)，具体的，子块预测模式的过程包括：分别得到待处理图像块中的每个 子块的运动信息，然后根据该每个子块各自的运动信息，得到每个子块各自的预测值，从而得到该待处理图像块的预测值)，其中，子块预测模式包括基于非平动运动模型的预测模式，例如仿射合并模式(affine merge mode)和仿射先进运动矢量预测模式(affine AMVP mode)；子块预测模式还可以包括ATMVP模式、planar帧间预测模式以及子块融合模式(sub-block based merging mode)等。
本申请实施例中，采用子块预测模式将待处理图像块继续划分为更小的图像块(以下均称为子块)，并根据所有子块的运动信息进行运动补偿，得到待处理图像块的预测值，从而提高预测效率。
下面对上述几种子块预测模式进行详细的介绍。
(1)affine merge模式
从解码端的角度，采用affine merge模式对待处理图像块执行帧间预测的过程包括：
步骤1、构建待处理图像块的控制点的候选运动信息列表。
其中，该候选运动信息列表中包括一个或多个候选运动信息多元组，该候选运动信息多元组包括待处理图像块的n1个控制点的候选运动信息，n1为大于或者等于2的正整数。
本申请实施例中，待处理图像块为一个CU，待处理图像块的控制点可以包括待处理图像块的左上顶点、右上顶点、左下顶点以及右下顶点的控制点，例如图6中的控制点可以为P1、P2、P3以及P4。上述候选运动信息多元组中包括n个控制点的运动信息，n的取值可以为2,3,4，结合图6，n1的取值为2时，待处理图像块的2个控制点可以为下述任一种情况：P1和P2，P1和P3，P1和P4，P2和P3，P2和P4，P3和P4；n的取值为3时，待处理图像块的3个控制点可以为下述任一种情况：P1、P2以及P3，P1、P2以及P4，P1、P3以及P4，P2、P3以及P4；n的取值为4时，待处理图像块的为4个为P1、P2、P3以及P4。
本申请实施例中，上述构建待处理图像块的控制点的候选运动信息列表即是确定待处理图像块的一个或多个候选运动信息多元组，具体的，可以利用继承的控制点运动矢量(inherited control point motion vectors)预测模式和/或构造的控制点运动矢量(constructed control point motion vectors)预测模式，构建控制点的候选运动信息列表。
第一种：采用继承的控制点运动矢量预测模式，构建控制点的候选运动信息列表包括：根据待处理图像块的相邻已重建的仿射编码块的运动模型，确定待处理图像块的控制点的候选运动信息。
上述确定待处理图像块的控制点的候选运动信息的方法具体包括：按照预设顺序，依次对待处理图像块的一个或多个相邻图像块执行第一处理过程，直到控制点的候选运动信息列表中候选运动信息多元组的数量等于第一预设数值或者直到遍历完所有相邻图像块。
其中，上述第一处理过程为：根据第i个相邻图像块所在的仿射编码块的n1个控制点的运动信息，确定出待处理图像块的n1个控制点的候选运动信息，并将包括待处理图像块的n1个控制点的候选运动信息的候选运动信息多元组存储于控制点的候选运动信息列表中，n1为大于或者等于2的正整数。
具体的，可以遍历待处理图像块的一个或多个相邻图像块，以从该一个或多个相邻图像块所在的仿射编码块获得该仿射编码块的控制点的运动矢量，进而根据该仿射编码块的n1个控制点的运动信息，采用仿射编码块的运动模型，推导出待处理图像块的n1个控制点的候选运动信息。
可以理解的是，运动信息包括运动矢量，上述确定待处理图像块的n1个控制点的候选运动信息即确定待处理图像块n1个控制点的候选运动矢量，并且在以下实施例中，运动信息即指运动矢量。
如图7所示，待处理图像块的5个相邻图像块分别为A1、B1、C1、D1、E1，可以按照第一预设的顺序(例如A1→B1→C1→D1→E1的顺序)遍历待处理图像块的相邻图像块，找到相邻图像块所在的仿射编码块，获取该仿射编码块的n1个控制点的运动信息，并且根据仿射编码块的运动模型(例如4参数(对应2个控制点)的运动模型或6参数(对应3个控制点)的运动模型)，确定待处理图像块的n1个控制点的运动信息。
示例性的，以待处理图像块的一个相邻图像块A1为例，如图7所示，待处理图像块的控制点分别记为M0、M1、M2、M3，其中，M0的坐标为(x 0,y 0)，M1的坐标为(x 1,y 1)，M2的坐标为(x 2,y 2)，M3的坐标为(x 4,y 4)，相邻图像块A1所在的仿射编码块记为仿射编码块1，该仿射编码块1的控制点分别记为N0、N1、N2、N3，其中，N0的坐标为(x 4,y 4)，N0的运动矢量为(vx 4,vy 4)，N1的坐标为(x 5,y 5)，N1的运动矢量为(vx 5,vy 5)，N2的坐标为(x 6,y 6)，N2的运动矢量为(vx 6,vy 6)，N3的坐标为(x 7,y 7)，N3的运动矢量为(vx 7,vy 7)。
若待处理图像块的2个控制点为M1和M2，则可以根据仿射编码块1的控制点N1和N2的运动信息，采用4参数的运动模型，确定该这2个控制点的候选运动信息，具体的，可以采用下述公式(1)计算控制点M1的候选运动矢量，采用公式(2)计算控制点M2的候选运动矢量:
Figure PCTCN2019116115-appb-000002
根据上述公式(1)可得控制点M1的候选运动矢量为(vx 0,vy 0)。
Figure PCTCN2019116115-appb-000003
根据上述公式(2)可得控制点M2的候选运动矢量为(vx 1,vy 1)。
综上，待处理图像块的控制点M1和M2的候选运动矢量为(vx 0,vy 0)和(vx 1,vy 1)，即得到一个候选运动信息二元组，并将该候选运动信息二元组存储于控制点的候选运动信息列表。同理，对于待处理图像块的其他相邻图像块，采用公式(1)和公式(2) 也可以得到控制点M1和M2的其他候选运动信息，并将候选运动信息二元组存储于控制点的候选运动信息列表中。
若待处理图像块的3个控制点为M1、M2和M3，则可以根据上述仿射编码块1的控制点N1、N2和N3的运动信息，采用6参数的运动模型，确定该3个控制点的候选运动信息，具体的，可以采用下述公式(3)计算控制点M1的候选运动矢量，采用公式(4)计算控制点M2的候选运动矢量，采用公式(5)计算控制点M3的候选运动矢量：
Figure PCTCN2019116115-appb-000004
根据上述公式(3)可得控制点M1的候选运动矢量为(vx 0,vy 0)。
Figure PCTCN2019116115-appb-000005
根据上述公式(4)可得控制点M2的候选运动矢量为(vx 1,vy 1)。
Figure PCTCN2019116115-appb-000006
根据上述公式(5)可得控制点M3的候选运动矢量为(vx 2,vy 2)。
综上，待处理图像块的控制点M1、M2以及M3的运动矢量为(vx 0,vy 0)、(vx 1,vy 1)和(vx 2,vy 2)，即得到一个候选运动信息三元组，并将该候选运动信息三元组存储于控制点的候选运动信息列表。同理，对于待处理图像块的其他相邻图像块，采用公式(3)、公式(4)以及公式(5)也可以得到控制点M1、M2以及M3的其他候选运动信息，并将候选运动信息三元组存储于控制点的候选运动信息列表中。
可以理解的是，根据上述方法确定待处理图像块的n1个控制点的运动信息。其中，若相邻图像块A1、B1、C1、D1、E1中某个相邻图像块不可得，则跳过该相邻图像块，继续根据下一个相邻图像块所在的仿射编码块的控制点的运动信息确定待处理图像块的n个控制点的运动信息。
本申请实施例中，图像块(或者子块)可得指的是：该图像块(或子块)存在或者已重建，即已编码或者已解码，并且其预测模式为帧间预测模式，否则认为该图像块(或子块)不可得，即图像块不存在或者图像块未编码或者相邻图像块采用的预测模式不是帧间预测模式。
可选的，本申请实施例中，上述相邻图像块A1、B1、C1、D1、E1的位置，相邻图像块的遍历顺序(即上述预设顺序)以及相邻图像块所在的仿射编码块的运动模型 均不作限定，实际应用中，也可以采用其他位置的相邻图像块、其他遍历顺序以及其他运动模型。
第二种：采用构造的控制点运动矢量预测模式，构建控制点的候选运动信息列表包括：
将待处理图像块的控制点周边邻近的已编码块(以下简称为相邻已编码块)的运动信息进行组合，作为待处理图像块的控制点的运动矢量。
需要说明的是，采用构造的控制点运动矢量预测模式时，不需要考虑控制点周边邻近的已编码块是否为仿射编码块。
构造的控制点的运动矢量预测方法存在以下两种实现方式。
在第一种实现方式中，将控制点的相邻已编码块的运动信息，确定为待处理图像块的控制点的候选运动信息，在得到n1个控制点的候选运动信息之后，将该n1个控制点的候选运动信息进行组合，可以得到待处理图像块的n1个控制点的候选运动信息的n1元组队列。
以待处理图像块的2个控制点为例，例如左上顶点的控制点和右上顶点的控制点，如图8所示，待处理图像块的左上顶点的控制点记为M0，控制点M0的相邻图像块分别为A2、B2、C2，并且A2、B2、C2为控制点M0的空域上的相邻图像块，右上顶点的控制点记为M1，控制点M1的相邻图像块分别为D2、E2，并且D2和E2控制点M1的空域上的相邻图像块，该待处理图像块的2个控制点的候选运动信息包括控制点M0的候选运动信息和控制点M1的候选运动信息。将控制点M0的运动矢量记为v 0(具体为(vx 0,vy 0))，控制点M1的运动矢量记为v 1(具体为(vx 1,vy 1))，将相邻图像块A2、B2、C2的运动矢量作为控制点M0的候选运动矢量，将相邻图像块D、E的运动矢量作为控制点M1的候选运动矢量，然后将控制点M0的候选运动矢量与控制点M1的候选运动矢量进行组合，可以得到待处理图像块的2个控制点的候选运动矢量的二元组队列：
{(v 0A2,v 1D2)，(v 0A2,v 1E2)，(v 0B2,v 1D2)，(v 0B2,v 1E2)，(v 0C2,v 1D2)，(v 0C2,v 1E2)}
可以理解，根据上述控制点的运动信息组合的方式，得到多组控制点的运动信息。对于待处理图像块的目标控制点包括3个控制点或4个控制点的情况，可以采用类似的控制点组合的方式确定控制点的运动信息。
在第二种实现方式中，对于待处理图像块的每一个控制点，按照预设顺序确定控制点的相邻图像块是否可得，并且将相邻图像块中第一个可得的相邻图像块的运动信息，确定为待处理图像块的对应的控制点的运动信息，然后再将控制点的运动信息进行组合，得到待处理图像块的n个控制点的运动信息的所有组合。
采用CPk(k＝1，2，3，4)表示待处理图像块的第k个控制点，CP1、CP2、CP3和CP4，示例性的，如图9所示，待处理图像块的控制点CP1相邻图像块为C3、F3、G3，这三个相邻图像块用于确定控制点CP1的运动信息，控制点CP2的相邻图像块为D3、E3，这两个相邻图像块用于确定控制点CP2的运动信息，控制点CP3的相邻图像块为A3、B3，这两个相邻图像块用于确定控制点CP3的运动信息，控制点CP4的相邻图像块为T1，用于确定控制点CP4的运动信息，其中，A3、B3、C3、D3、E3、F3和G3均为空间上的相邻图像块，T1为时域上的相邻图像块。
对于控制点CP1，可以按照F3→C3→G3的顺序依次获取各个相邻图像块的运动信息，将检测到的第一个可得的相邻图像块的运动信息作为控制点M0的运动信息。具体的，确定控制点CP1的运动信息的过程如下：
(1)若相邻图像块F3可得，则将相邻图像块F3的运动信息作为控制点CP1的运动信息vcp1，无需再判断相邻图像块C3和相邻图像块G3是否可得；
(2)若相邻图像块F3不可得，则按照上述顺序确定相邻图像块C3是否可得；
(3)若相邻图像块C3可得，则将相邻图像块C3的运动信息作为控制点CP1的运动信息vcp1，无需再判断相邻图像块G3是否可得；
(4)若相邻图像块C3不可得，则继续确定相邻图像块G3是否可得；
(5)若相邻图像块G3可得，则将相邻图像块G3的运动信息作为控制点CP1的运动信息vcp1；
(6)若相邻图像块G3不可得，则确定控制点CP1的运动信息不存在。
对于控制点CP2，可以按照D3→E3的顺序依次获取各个相邻图像块的运动信息，将检测到的第一个可得的相邻图像块的运动信息作为控制点CP2的运动信息vcp2。
对于控制点CP3，可以按照A3→B3的顺序依次获取各个相邻图像块的运动信息，将检测到的第一个可得的相邻图像块的运动信息作为控制点CP3的运动信息vcp3。
上述确定控制点CP2和控制点CP3的运动信息的过程与确定控制点CP1的运动信息的过程类似，具体可以参见上述确定控制点CP3的运动信息的描述，此处不再赘述。
对于控制点CP4，若相邻图像块T1可得，将相邻图像块T1的运动信息作为控制点CP4的运动信息vcp4。
上述获得待处理图像块的所有控制点的运动信息之后，将待处理图像块的控制点进行组合，得到n个控制点的运动信息的多元组。
若构造2个控制点的运动信息，则将上述控制点CP1、CP2、CP3、CP4中的两个控制点的运动信息进行组合，得到的控制点的运动信息的二元组包括：(vcp1，vcp2)，(vcp1，vcp3)，(vcp1，vcp4)，(vcp2，vcp3)，(vcp2，vcp4)，(vcp3，vcp4)。
若构造3个控制点的运动信息，则将上述控制点CP1、CP2、CP3、CP4中的三个控制点的运动信息进行组合，得到的控制点的运动信息的三元组包括：(vcp1，vcp2，vcp3)，(vcp1，vcp2，vcp4)，(vcp2，vcp3，vcp4)，(vcp1，vcp3，vcp4)。
若构造4个控制点的运动信息，则将上述控制点CP1、CP2、CP3、CP4中的三个控制点的运动信息进行组合，得到的控制点运动信息的四元组为：(vcp1，vcp2，vcp3，vcp4)。
综上所述，通过上述方法构造的控制点的候选运动矢量列表，以用于确定待处理图像块的子块的运动信息。
可以理解的是，编码端构建控制点的候选运动信息列表的方法与解码端相同。
步骤2、从待处理图像块的候选运动信息列表中确定待处理图像块的n1个控制点的目标运动信息。
merge affine模式下，编码端构造完成待处理图像块的控制点的候选运动信息列表之后，利用候选运动信息列表中的每个候选运动信息多元组，采用上述仿射运动模型 (参考下文中的相关描述)获得待处理图像块中每个子块的运动矢量，进而得到每个子块的运动矢量所指向的参考帧中位置的像素值，作为其预测值，进行仿射变换运动补偿。编码端计算待处理图像块中每个像素点的原始值和预测值之间差值的平均值，并选择最小的平均值所对应的候选运动信息多元组作为最优的候选运动信息组合，也就是说，编码端从该候选运动信息列表中确定一个最优的候选运动信息多元组，将该最优的候选运动信息多元组作为待处理图像块的n1个控制点的目标运动信息，进而编码端将上述最优的候选运动信息多元组在候选运动信息列表中的索引号(记为affine Merge index)传递至解码端。
对应地，解码端解析码流得到最优的候选运动信息多元组在候选运动信息列表中的索引，从而解码端将n1个控制点的候选运动信息列表中该索引对应的最优的候选运动信息多元组作为n2个控制点的目标候选运动信息。
步骤3、根据待处理图像块的n1个控制点的目标运动信息，采用仿射运动模型，确定待处理图像块的一个或多个子块各自的运动信息。
本申请实施例中，常用的非平动运动模型包括4参数仿射运动模型或6参数仿射运动模型。
其中，4参数的仿射运动模型为：
Figure PCTCN2019116115-appb-000007
其中，vx和vy组成的(vx,vy)为子块的运动矢量，(x,y)为子块的坐标(具体为相对于待处理图像块的左上顶点像素的坐标)，a 1、a 2、a 3、a 4为该仿射运动模型的4个参数，该参数与待处理图像块的2个控制点的运动信息有关，结合图7，若2个控制点分别为控制点M0和M1，根据控制点M1和控制点M2的运动信息，得到子块的运动信息为：
Figure PCTCN2019116115-appb-000008
其中，(vx 0,vy 0)为控制点M1的运动矢量，(vx 1,vy 1)为控制点M2的运动矢量，w为待处理图像块的宽。
6参数的仿射运动模型为：
Figure PCTCN2019116115-appb-000009
同理a 1、a 2、a 3、a 4、a 5、a 6为该仿射变换模型的参数，该参数与目标控制点的运动信息有关，若上述目标控制点包括的三个控制点分别为上述控制点M0、M1以及M3，根据控制点M1、控制点M2以及控制点M3的运动信息，得到第一子块中目标像素点的运动信息为：
Figure PCTCN2019116115-appb-000010
其中，(vx 0,vy 0)为控制点M1的运动矢量，(vx 1,vy 1)为控制点M2的运动矢量，(vx 2,vy 2)为控制点M3的运动矢量。
步骤4、根据待处理图像块的一个或多个子块各自的运动信息，确定该一个或多个子块各自的预测值，进而得到待处理图像块的预测值。
本申请实施例中，由于子块的运动信息可以表征待处理图像块的子块可以由已重建的图像块的子块经过偏移得到，因此，可以根据待处理图像块中每一个子块各自的运动信息快速地确定每一个子块的预测值(即预测块)。具体的，根据待处理图像块的子块的运动信息中的运动矢量和待处理图像块的子块的位置信息，在待处理图像块的参考帧中，确定待处理图像块的子块的运动信息中的运动矢量指向的参考块，并将该参考块作为待处理图像块的子块的预测值，对待处理图像块的所有子块按照上述预测方法得到所有子块的预测值，即得到了待处理图像块的预测值。
(2)affine AMVP模式
从解码端的角度，采用affine AMVP模式对待处理图像块执行帧间预测的过程：
步骤1、构建待处理图像块的控制点的候选运动信息列表。
本申请实施例中，affine AMVP模式下构建控制点的候选运动信息列表的方法与上述affine merge模式下构造控制点的候选运动信息列表的方法类似，具体参见上述实施例的相关描述，此处不再赘述。
步骤2、根据待处理图像块的候选运动信息列表，确定待处理图像块的n1个控制点的目标运动信息。
affine AMVP模式下，编码端构造完成待处理图像块的控制点的候选运动信息列表之后，利用候选运动信息列表中的每个候选运动信息多元组，采用上述仿射运动模型(参考下文中的相关描述)获得待处理图像块中每个子块的运动矢量，进而得到每个子块的运动矢量所指向的参考帧中位置的像素值，作为其预测值，进行仿射变换运动补偿。编码端计算待处理图像块中每个像素点的原始值和预测值之间差值的平均值，并选择最小的平均值所对应的候选运动信息多元组作为最优的候选运动信息组合，将该最优的候选运动信息多元组作为待处理图像块的n1个控制点的运动信息的预测值，并且编码端以控制点的运动信息的预测值中的运动矢量(简称为控制点的运动矢量预测值)作为搜索起始点在一定搜索范围内进行运动搜索，获得这n1个控制点的运动矢量(control point motion vectors，CPMV)，并得到控制点的运动矢量与控制点的运动矢量预测值之间的差值(control point motion vectors differences，CPMVD)，进而编码端将上述最优的候选运动信息多元组在候选运动信息列表中的索引以及CPMVD传输至解码端。
对应地，解码端解析码流得到最优的候选运动信息多元组在候选运动信息列表中的索引以及CPMVD，从而解码端将n1个控制点的候选运动信息列表中该索引对应的最优的候选运动信息多元组作为n1个控制点的候选运动信息预测值，并将n1个控制点的候选运动信息预测值与CPMVD之和，作为n1个控制点的目标运动信息。
步骤3、根据待处理图像块的n1个控制点的目标运动信息，采用仿射运动模型，确定待处理图像块的一个或多个子块各自的运动信息。
步骤4、根据待处理图像块的一个或多个子块各自的运动信息，确定该一个或多个子块各自的预测值，进而得到待处理图像块的预测值。
步骤3与步骤4可参见上述affine merge模式中的步骤3和步骤4的描述，此处不再赘述。
(3)ATMVP模式
采用ATMVP模式对待处理图像块执行帧间预测的过程包括：
步骤1、确定待处理图像块的运动信息。
步骤2、根据待处理图像块的运动信息以及待处理子块在该待处理图像块中的位置，在参考图像中确定该待处理子块的对应子块；
步骤3、根据对应子块的运动信息，确定当前待处理子块的运动信息。
即将对应子块的运动信息，确定当前待处理子块的运动信息。
步骤4、根据待处理子块的运动信息对待处理子块进行运动补偿预测，得到待处理子块的预测值，基于待处理图像块的所有子块的预测值得到待处理图像块的预测值。
(4)planar帧间预测模式
通过获取当前每一个子块的上边空域相邻位置、左边空域相邻位置、右边和下边位置的运动信息，求其平均值，并转化为当前每一个子块的运动信息。
对于坐标为(x,y)子块，子块运动矢量P(x，y)使用水平方向插值运动矢量和垂直方向插值运动矢量计算得到：
p(x,y)＝(H×p h(x,y)+W×p V(x,y)+H×W)/(2×H×W)      (10)
水平方向插值运动矢量和垂直方向插值运动矢量通过使用当前子块左侧、右侧、上方和下侧的运动矢量计算得到：
P h(x,y)＝(W-1-x)×L(-1,y)+(x+1)×R(W,y)        (11)
P v(x,y)＝(H-1-y)×A(x,-1)+(y+1)×B(x,H)        (12)
其中L(-1，y)和R(W，y)代表当前子块左侧和右侧位置的运动矢量，A(x，-1)和B(x，H)表示当前子块上方和下侧位置的运动矢量。
左侧运动矢量L和上方运动矢量A从待处理图像块的空域临近块得到。根据子块坐标(x，y)得到预设位置(-1，y)和(x，-1)处的图像块的运动矢量L(-1，y)和A(x，-1)。
右侧运动矢量R(W，y)和下方运动矢量B(x，H)通过以下方法提取：
1、提取待处理图像块右下位置的时域运动信息BR；
2、使用提取到的右上空域临近位置的运动矢量AR和右下位置的时域运动信息BR加权计算得到右侧运动矢量R(W，y)，如下式：
R(W,y)＝((H-y-1)AR+(y+1)BR)/H             (13)
3、使用提取到的左下空域临近位置的运动矢量BL和右下位置的时域运动信息BR加权计算得到下方运动矢量B(x，H)，如下式：
B(x,H)＝((W-x-1)BL+(x+1)BR)/W           (14)
计算中使用的所有运动矢量都被缩放到指向特定参考帧队列中第一个参考帧。
(5)子块融合模式
子块融合模式指的是几种运动信息进行组合来构建候选列表，该候选列表可以称为子块融合候选列表(sub-block based merging candidate list)，示例性的，可以采用上述继承的控制点运动矢量预测模式、构造的控制点运动矢量预测模式或ATMVP模式中两种或者两种以上的预测模式获得的候选运动矢量来构建子块融合候选列表，进而对当前图像块进行预测。
采用子块融合模式对待处理图像块执行帧间预测的过程包括：
步骤1、构造待处理图像块的子块融合候选列表。
示例性的，以子块融合模式包括高级时域运动矢量预测方法、继承的控制点运动矢量预测模式以及构造的控制点运动矢量预测模式为例，介绍子块融合候选列表的构建过程。将上述ATMVP模式中运动矢量预测方法获得的运动信息(该运动信息为子块的运动信息)、上述继承的控制点运动矢量预测模式获得运动信息(该运动信息包括多个候选运动信息多元组)以及上述构造的控制点运动矢量预测模式(该运动信息包括多个候选运动信息多元组)按照预设顺序(例如先ATMVP模式对应的运动矢量，后继承的控制点的运动矢量预测模式对应的运动矢量，再构造的控制点的运动矢量预测模式对应的运动矢量的顺序)添加(可以理解为存储)至子块融合候选列表中。
可选的，将子块融合候选列表根据特定的规则(例如检查可用性或者去除重复项等)进行剪枝和排序，并可将其截断或填充至特定的个数，子块融合候选列表中包括的运动矢量的个数可以称为子块融合候选列表的最大有效候选个数或者成为子块融合候选列表的最大列表长度。
步骤2、从子块融合候选列表中确定目标候选运动信息。
在编码端，利用子块融合候选列表中的每个候选运动信息，得到待处理图像块的像素的预测值，并计算待处理图像块中每个像素点的原始值和预测值之间差值的平均值，选择差值的平均值最小对应的候选运动信息，将表示该候选运动信息在候选运动信息列表中位置的索引号编码入码流发送给解码端。
在解码端，解析索引号，根据索引号从上述子块融合候选列表中确定控制点的运动信息(若为继承的控制点的运动矢量预测模式或构造的控制点的运动矢量预测模式)或子块的运动信息(若为ATMVP或planar帧间预测模式)作为目标候选运动信息。
在本申请实施例中，当使用帧间预测模式解码待处理图像块时，可以使用语法元素以信号形式发送帧间预测模式。目前解析待处理图像块所采用的帧间预测模式的部分语法结构可以参见表1所示。需要说明的是，语法结构中的语法元素还可以通过其他标识来表示，本申请实施例对此不作具体限定。
表1
Figure PCTCN2019116115-appb-000011
Figure PCTCN2019116115-appb-000012
Figure PCTCN2019116115-appb-000013
结合表1，在标准文本或代码中，用于指示待处理图像块是否采用merge模式(即融合模式或合并模式)进行帧间预测的标识可以通过语法元素merge_flag[x0][y0]来表示，换句话说，merge_flag[x0][y0]用于指示对待处理图像块进行帧间预测是否允许采用merge模式。示例性的，当merge_flag[x0][y0]＝1时，指示待处理图像块采用融合模式，当merge_flag[x0][y0]＝0时，指示待处理图像块不采用融合模式。x0，y0表示待处理图像块在图像中的坐标。
在标准文本或代码中，用于指示待处理图像块是否采用子块融合模式进行帧间预测的标识可以通过语法元素merge_subblock_flag[x0][y0]来表示，换句话说，语法元素merge_subblock_flag[x0][y0]用于指示对待处理图像块进行帧间预测是否允许采用子块预测模式。示例性的，待处理图像块所在条带的类型(slice_type)为P型或者B型， 当merge_subblock_flag[x0][y0]＝＝1时，指示对待处理图像块进行帧间预测采用子块融合模式，即允许采用子块融合模式，merge_subblock_flag[x0][y0]＝＝0时，指示对待处理图像块进行帧间预测不采用子块融合模式，即不允许采用子块融合模式。
语法元素merge_idx[x0][y0]用于指示上述merge模式下merge候选列表的索引值，即用于指示merge模式被选中时(也就是说采用merge模式对待处理图像块进行预测时)，目标候选运动矢量在该merge候选列表中的位置。
语法元素merge_subblock_idx[x0][y0]用于指示在子块融合模式下子块融合候选列表的索引值，即用于指示子块融合模式被选中时(也就是说采用子块融合模式对待处理图像块进行预测时)，目标候选运动矢量在子块融合候选列表中的位置。
语法元素inter_affine_flag[x0][y0]可用于指示在待处理图像块所在条带为P型条带或者B型条带时，待处理图像块是否采用基于affine AMVP模式进行预测。
语法元素cu_affine_type_flag[x0][y0]可以用于指示在待处理图像块所在条带为P型条带或者B型条带时，该待处理图像块是否采用6参数仿射运动模型进行运动补偿。示例性的，cu_affine_type_flag[x0][y0]＝0，指示待处理图像块不采用6参数仿射运动模型进行运动补偿，仅采用4参数仿射运动模型进行运动补偿；cu_affine_type_flag[x0][y0]＝1，指示待处理图像块采用6参数仿射运动模型进行运动补偿。
在表1中，ae(v)表示采用基于自适应二元算术编码(context-based adaptive binary arithmetic coding，cabac)编码的语法元素。
参见表2所示，MotionModelIdc[x0][y0]＝1，指示采用4参数仿射运动模型，MotionModelIdc[x0][y0]＝2，指示采用6参数仿射运动模型，MotionModelIdc[x0][y0]＝0指示采用平动运动模型。
表2
MotionModelIdc[x0][y0] motion model for motion compensation(运动补偿采用的运动模型)
0 translational motion(平动运动)
1 4-parameter affine motion(4参数仿射运动)
2 6-parameter affine motion(6参数仿射运动)
其中，变量MaxNumMergeCand、MaxNumSubblockMergeCand用于表示最大列表长度，指示构造的候选运动矢量列表的最大长度，inter_pred_idc[x0][y0]用于指示预测方向，PRED_L1用于指示后向预测，num_ref_idx_l0_active_minus1用于指示前向参考帧列表的参考帧个数，ref_idx_l0[x0][y0]用于指示待处理图像块的前向参考帧索引值，mvd_coding(x0,y0,0,0)用于指示第一个运动矢量差，mvp_l0_flag[x0][y0]用于指示前向MVP候选列表索引值，PRED_L0用于指示前向预测，num_ref_idx_l1_active_minus1用于指示后向参考帧列表的参考帧个数，ref_idx_l1[x0][y0]用于指示待处理图像块的后向参考帧索引值，mvp_l1_flag[x0][y0]用于指示后向MVP候选列表索引值。
结合表1和表2，通过表1中的相关语法元素可以确定表2中的MotionModelIdc[x][y]，具体的：
当merge_flag[x0][y0]＝＝1时，
MotionModelIdc[x][y]＝merge_subblock_flag[x0][y0]
当merge_flag[x0][y0]＝＝1时，
MotionModelIdc[x][y]＝inter_affine_flag[x0][y0]+cu_affine_type_flag[x0][y0]
步骤3、根据目标候选运动信息，得到待处理图像块的一个或多个子块各自的预测值，进而得到待处理图像块的预测值。
具体的，若目标候选运动信息为控制点的运动信息，则根据上述affine merge模式中的仿射运动模型，确定一个或多个子块的运动信息，基于一个或多个子块的运动信息，得到一个或多个子块的预测值，进而得到待处理图像块的预测值。若目标候选运动信息为子块的运动信息，则基于子块的运动信息，得到子块的预测值，进而得到待处理图像块的预测值。
本申请实施例提供了一种帧间预测方法及装置，可以将子块融合模式应用于帧间预测方法中，在子块融合模式中能够实现多种预测模式的兼容，从而提高解码效率。其中，方法和装置是基于同一发明构思的，由于方法及装置解决问题的原理相似，因此装置与方法的实施可以相互参见，重复之处不再赘述。
下面基于上述对于帧间预测模式中的多种预测模式的介绍，并结合附图从解码端的角度对本申请实施例提供的帧间预测方法进行详细说明，具体可以由解码器30执行，或者由解码器中的熵解码单元和预测处理单元来实现，或者由处理器来执行。
如图10所示，本申请实施例提供的帧间预测方法可以包括：
S101、确定待处理图像块的子块融合候选列表，该子块融合候选列表包括根据多个候选预测模式获得的至少一个候选运动矢量，该多个候选预测模式中包括planar帧间预测模式。
本申请实施例中，上述多个候选预测模式可以包括planar帧间预测模式、ATMVP模式、继承的控制点的运动矢量预测模式、构造的控制点的运动矢量预测模式或零运动矢量预测模式中的两种或多种，其中，零运动矢量预测模式对应的运动矢量为零运动矢量。
上述多个候选预测模式获得的至少一个候选运动矢量包括：第一候选运动矢量、第二候选运动矢量、第三候选运动矢量、第四候选运动矢量或第五候选运动矢量，其中，第一候选运动矢量根据planar帧间预测模式获得，第二候选运动矢量根据ATMVP模式获得，第三候选运动矢量根据继承的控制点运动矢量预测模式获得，第四候选运动矢量根据构造的控制点运动矢量预测模式获得，第五候选运动矢量为零运动矢量(即零运动矢量预测模式对应的运动矢量)。
可以理解的是，子块融合候选列表中包括上述第一候选运动矢量、第二候选运动矢量、第三候选运动矢量、第四候选运动矢量或第五候选运动矢量中的一种或者多种，具体根据实际构建该子块融合候选列表中的候选运动矢量的规则确定。
对于获取不同预测模式对应的候选运动矢量的方法，可以参见上述实施例中的不同的预测模式下进行帧间预测过程的相关描述，此处不再赘述。
可选的，上述确定的子块融合候选列表中的候选运动矢量的数量为小于或等于5的正整数，例如，候选运动矢量的数量可以为1，2，3，4或5，具体的，该子块融合 候选列表中的候选运动矢量的数量在编码端和解码端进行设定。
本申请实施例中，在不影响编解码效果或者对编解码效果影响很小的情况下，子块融合候选列表中的候选运动矢量的数量较少时，可以降低构建子块融合候选列表的复杂度，并且候选运动矢量的数量较少时，可以减少从多个候选运动矢量中确定目标候选运动矢量的计算量，从而可以有效地降低编解码的复杂度。
可选的，本申请实施例中，子块融合候选列表中包括的不同候选运动矢量的排列顺序可以不同，具体可以包括以下几种情况：
在第一种实现方式中，当子块融合候选列表中存在第一候选运动矢量和第二候选运动矢量时，该第一候选运动矢量排列在第二候选运动矢量之后。
在第二种实现方式中，当子块融合候选列表中存在第一候选运动矢量和第三候选运动矢量时，该第一候选运动矢量排列在第三候选运动矢量之后。
在第三种实现方式中，当子块融合候选列表中存在第一候选运动矢量和第四候选运动矢量时，该第一候选运动矢量排列在第四候选运动矢量之后。
需要说明的是，本申请实施例中，子块融合候选列表中不同的候选运动矢量的排列顺序与确定子块融合候选列表的过程中多种候选预测模式的遍历顺序有关，具体将在下述实施例中进行详细的描述。
S102、从码流中解析索引信息，该索引信息用于指示子块融合候选列表中的目标候选运动矢量。
结合上述S101中的相关描述，解码端完成构建子块融合候选列表，该子块融合候选列表中的每个候选运动矢量在该子块融合候选列表中的位置可以由候选运动矢量的索引来指示，每个候选运动矢量有对应的索引号。
本申请实施例中，编码端完成待处理图像块的编码之后，编码端将子块融合候选列表中的目标候选运动矢量的索引信息也写入码流，传递至解码端，解码端从码流中解析该索引信息，即可确定目标候选运动矢量在子块融合候选列表中的位置，从而在构建的子块融合候选列表中确定目标候选运动矢量。
参见表3，为本申请实施例提供的解析待处理图像块所采用的帧间预测模式的部分语法结构。
表3
Figure PCTCN2019116115-appb-000014
Figure PCTCN2019116115-appb-000015
Figure PCTCN2019116115-appb-000016
在表3中，if((sps_affine_enabled_flag||sps_sbtmvp_enabled_flag||sps_planar_enabled_flag)&&cbWidth>＝8&&cbHeight>＝8)指的是候选预测模式满足仿射预测模式(包括继承的控制点运动矢量预测模式和\或构造的控制点运动矢量预测模式)、ATMVP模式或planar帧间预测模式中的任一种，当前编解码块的长和宽均大于等于8。
结合表3，可选的，将子块融合候选列表根据特定的规则进行剪枝和排序，并可将其截断或填充至特定的个数。
若sps_sbtmvp_enabled_flag为1，将ATMVP模式对应的第二候选运动矢量添加到子块融合候选列表。
若sps_affine_enabled_falg为1，利用继承的控制运动矢量预测模式，推导得到待处理图像块的候选的控制点运动矢量，添加到子块融合候选列表。示例性的，按照图7中A1、B1、C1、D1、E1的顺序遍历待处理图像块的周边相邻位置块，找到该位置所在的仿射编码块，获得该仿射编码块的控制点运动矢量，进而通过其运动模型，推导出待处理图像块的候选的控制点运动矢量。
需要说明的是，如果此时子块融合候选运动矢量列表为空，则将该候选的控制点 运动矢量添加到子块融合候选列表；否则依次遍历子块融合候选列表中的运动矢量，检查子块融合候选列表中是否存在与该候选的控制点运动矢量相同的运动矢量。如果子块融合候选列表中不存在与该候选的控制点运动矢量相同的运动矢量，则将该候选的控制点运动矢量添加到子块融合候选列表。
其中，判断两个候选运动矢量是否相同需要依次判断它们的前后向参考帧、以及各个前后向运动矢量的水平和竖直分量是否相同。只有当以上所有元素都不相同时才认为这两个运动矢量是不同的。
如果子块融合候选列表中的候选运动矢量个数达到最大列表长度，即MaxNumSubblockMergeCand(MaxNumSubblockMergeCand为正整数，如1，2，3，4，5等)，则子块融合候选列表构建完成，否则遍历下一个相邻位置块。
若sps_affine_enabled_falg为1，利用构造的控制点运动矢量预测模式，推导得到待处理图像块的候选的控制点运动矢量，并加入子块融合候选列表，参见图8所示，按照预置的顺序遍历控制点的组合，得到合法的组合作为候选的控制点运动矢量。
示例性的，一种预置的顺序如下：Affine(CP1,CP2,CP3)->Affine(CP1,CP2,CP4)->Affine(CP1,CP3,CP4)->Affine(CP2,CP3,CP4)->Affine(CP1,CP2)->Affine(CP1,CP3)，总共6种组合。
示例性的，若sps_affine_type_flag为1，一种预置顺序如下：Affine(CP1,CP2,CP3)->Affine(CP1,CP2,CP4)->Affine(CP1,CP3,CP4)->Affine(CP2,CP3,CP4)->Affine(CP1,CP2)->Affine(CP1,CP3)，总共6种组合。本申请实施例对6种组合添加到子块融合候选列表的先后顺序不作具体限定。
若sps_affine_type_flag为0，一种预置顺序如下：Affine(CP1,CP2)->Affine(CP1,CP3)，总共2种组合。本申请实施例对2种组合添加到子块融合候选列表的先后顺序不作具体限定。
若组合对应的控制点运动矢量不可得，则认为该组合不可得。若组合可得，确定该组合的参考帧索引(两个控制点时，选择参考帧索引最小的作为该组合的参考帧索引；大于两个控制点时，先选择出现次数最多的参考帧索引，若有多个参考帧索引的出现次数一样多，则选择参考帧索引最小的作为该组合的参考帧索引)，并将控制点的运动矢量进行缩放，若缩放后的所有控制点的运动信息一致，则该组合不合法。
需要说明的是，如果此时子块融合候选列表为空，则将该候选的控制点运动矢量加入子块融合候选列表；否则依次遍历子块融合候选列表中的运动信息，检查子块融合候选列表中是否存在与该候选的控制点运动矢量相同的运动矢量，如果子块融合候选列表中不存在与该候选的控制点运动矢量相同的运动矢量，则将该候选的控制点运动矢量添加到子块融合候选列表。
若sps_planar_enabled_flag为1，将planar帧间预测模式对应的第一候选运动矢量添加到子块融合候选列表。
可选地，本申请实施例还可以对子块融合候选列表进行填充，比如，经过上述遍历过程后，此时子块融合候选列表的长度小于最大列表长度(MaxNumSubblockMergeCand)，则可以对子块融合候选列表进行填充，直到子块融合候选列表的长度等于MaxNumSubblockMergeCand。本申请实施例中，可以通过补充 零运动矢量的方法进行填充，或者通过将现有列表中已存在的候选运动矢量进行组合、加权平均的方法进行填充。需要说明的是，其他获得子块融合候选列表填充的方法也可适用于本申请，在此不做赘述。
需要说明的是，本申请实施例中，当子块融合候选列表中包括一种预测模式对应的一个候选运动矢量时，即子块融合候选列表中仅包括一个候选运动矢量，该候选运动矢量即为目标候选运动矢量，则编码端无需编码目标候选运动矢量的索引，解码端也无需解码目标候选运动矢量的索引，解码端确定出该预测模式对应的候选运动矢量之后，直接对待处理图像进行预测。
可选的，可以采用二值化方法来表示候选运动矢量的索引信息，如采用截断莱斯编码(truncated rice，TR)码来表示索引信息，TR码是根据最大索引值，将各个索引值映射到不同的二进制数，并且子块融合列表中排列在先的候选运动矢量对应的索引的码字长度小于或等于排列在后的候选运动矢量对应的索引的码字长度。
示例性的，最大索引值为4，可以按照表4将各个索引值二值化。
表4
Figure PCTCN2019116115-appb-000017
结合表2，若子块融合候选列表中包括的候选运动矢量的数量为5，各个候选运动矢量的索引分别为0，1，2，3，4，可知排列在线的候选运动矢量对应的索引的码字长度小于或等于排列在后的候选运动矢量对应的索引的码字长度，例如索引1的码字长度小于索引2的码字长度，索引3的码字长度等于索引4的码字长度。
示例性的，最大索引值为2，可以按照表5将各个索引值二值化。
表5
Figure PCTCN2019116115-appb-000018
可选的，本申请实施例中，可以不限制S101与S102的执行顺序，解码端可以先执行S101，后执行S102，也可以先执行S102，后执行S101，还可以同时执行S101和S102。
S103、基于该索引信息指示的目标候选运动矢量，得到待处理图像块的预测值。
本申请实施例中，根据目标候选运动矢量得到待处理图像块的预测值包括：根据目标候选运动矢量确定待处理图像块中对应的一个子块的运动矢量，从而得到子块的预测值，解码端按照上述方法得到待处理图像块中的所有子块的预测值，则得到待处理图像块的预测值。
可以理解的是，目标候选运动矢量对应的预测模式不同时，则采用对应的预测模 式下的帧间预测过程，实现对待处理图像的预测，具体可以参见上述实施例中的详细描述，此处不再赘述。
需要说明的是，本申请实施例中，解码端确定待处理图像块的子块融合候选列表的方法与编码端确定待处理图像块的子块融合候选列表的方法相同，也就是说解码端确定的子块融合候选列表与对应的编码端确定的子块融合候选列表相同。与上述解码端不同的是，编码端确定出子块融合候选列表之后，编码端从子块融合候选列表中的候选运动矢量中确定出目标候选运动矢量，具体的，编码端遍历子块融合候选列表中的每个候选运动矢量，根据该候选运动矢量对待处理图像块进行运动补偿，得到待处理图像块的预测值(即重建值)，然后根据最小绝对变换差值和(sum of absolute transformed differences，SATD)准则，将最小的SATD对应的候选运动矢量确定为子块融合模式下的目标候选运动矢量(即最优的候选运动矢量)，如此，根据该目标运动矢量得到的待处理图像块的预测值是子块融合模式下的待处理图像块的预测值，如果待处理图像块的预测模式不再包含其他的预测模式(例如merge模式)，编码端将目标候选运动矢量的索引(即merge_subblock_idx)写入码流，传递至解码端。
可选的，本申请实施例中，如果待处理图像块的预测模式除了子块融合模式之外，还包括其他预测模式(例如merge模式或triangle PU模式等)，那么编码端采用子块融合模式以及其他的预测模式分别对待处理图像块进行预测，得到不同的预测模式各自对应的待处理图像块的预测值，并且确定各种模式下的目标候选运动矢量的索引，根据率失真优化技术确定率失真最小的预测模式为待处理图像块的最佳预测模式。应理解，若该最佳预测模式为子块融合模式，则将子块融合模式下的目标候选运动矢量的索引(merge_subblock_idx)写入码流传递至解码端，若该最佳预测模式为其他预测模式，例如merge模式，则将merge模式下的目标候选运动矢量(即merge_idx)写入码流，传递至解码端。
本申请实施例提供的帧间预测方法，由于视频解码装置可以确定待处理图像块的子块融合候选列表，该子块融合候选列表包括根据多个候选预测模式获得的至少一个候选运动矢量，该多个候选预测模式中包括planar帧间预测模式；并且从码流中解析索引信息，该索引信息用于指示子块融合候选列表中的目标候选运动矢量；以及基于该索引信息指示的目标候选运动矢量，得到待处理图像块的预测值，可知，在采用子块融合模式对待处理图像块进行解码时，在候选预测模式中引入了planar帧间预测模式，如此，使得子块融合模式中的候选运动矢量的种类更加丰富，并且能够在子块融合模式中实现多种预测模式的兼容，从而提高解码效率。
通过S101-S103的描述可知，子块融合模式下对待处理图像块进行预测的过程中，候选预测模式可以包括上述S101中描述的多种候选预测模式中的两种或两种以上，并且在确定子块融合候选列表时，该子块融合候选列表中的候选运动矢量的种类以及各个候选运动矢量的排列顺序均与多种候选预测模式的遍历顺序有关，因此，对于编码端和解码端，可以通过多种不同的方法确定子块融合候选列表，进而对待预测图像块进行预测，得到待预测图像块的预测值。
下面对采用子块融合模式进行帧间预测的过程中涉及到的几种确定子块融合候选列表的方法进行详细的介绍。
第一种方法：候选预测模式包括ATMVP，继承的控制点运动矢量预测模式，planar帧间预测模式，构造的控制点运动矢量预测模式以及零运动矢量预测模式，并且这几种候选预测模式的遍历顺序以及根据每种预测模式可获得的候选运动矢量的最大数量可参见表6。
表6
Figure PCTCN2019116115-appb-000019
如图11所示，结合上述表6，本申请实施例提供的帧间预测方法可以包括S201-S211：
S201、获取ATMVP模式对应的第二候选运动矢量，若该第二候选运动矢量可用，则将其添加至子块融合候选列表。
本申请实施例中，解码端获取到第二候选运动矢量之后，首先对该第二候选运动矢量进行可用性检查，若该第二候选运动矢量可用，则将第二候选运动矢量添加至子块融合候选列表中；若该第二候选运动矢量不可用，则将其丢弃。应理解，第二候选运动矢量是子块的候选运动矢量，该第二候选运动矢量可用指的是在获取第二候选运动矢量的过程中，当前子块的相邻块可得。
需要说明的是，在初始状态下，子块融合候选列表是空的列表，即该子块融合候选列表中包括的候选运动矢量的数量为0。
对于获取ATMVP模式对应的候选运动矢量的方法可以参见上述实施例中的相关描述，此处不再赘述。
S202、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
上述子块融合候选列表中的候选运动矢量的数量也可以称为子块融合候选列表的长度，上述预设数量也可以称为子块融合候选列表的预设长度，结合上述对S101的相关描述可知，子块融合候选列表中的候选运动矢量的数量为小于或等于5的正整数。
本申请实施例中，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S203，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S201之后，已完成子块融合候选列表的确定。
S203、获取继承的控制点运动矢量预测模式对应的第三候选运动矢量，若该第三候选运动矢量可用且不重复，则将该第三候选运动矢量添加至子块融合候选列表。
本申请实施例中，可以向子块融合候选列表中添加的第三候选运动矢量的数量最 多为2个，解码端获取到2个第三候选运动矢量之后，检查其可用性并剔除重复项之后，向子块融合候选列表中添加指定数量的第三候选运动矢量，该指定数量是根据预设数量、第二候选运动矢量是否可用以及第三候选运动矢量的最大数量确定的，通过S202可以确定需要向子块融合候选列表中添加几个第三候选运动矢量。
结合S201-S203，示例性的，子块融合候选列表中的候选运动矢量的预设数量为1，若上述第二候选运动矢量可用，通过S202可以确定子块融合候选列表中的候选运动矢量的数量等于预设数量，则子块融合候选列表中的候选运动矢量的数量已经达到预设数量，解码端完成子块融合候选列表的确定，无需再将其他候选预测模式对应的候选运动矢量添加至子块融合候选列表中了；若上述第二候选运动矢量不可用，通过S202可以确定子块融合候选列表中的候选运动矢量的数量小于预设数量，则还需向子块融合候选列表中添加1个候选运动矢量，进而解码端向子块融合候选列表中添加1个第三候选运动矢量，至此完成子块融合候选列表的确定。
对于获取继承的控制点运动矢量预测模式对应的候选运动矢量的方法可以参见上述实施例中的相关描述，此处不再赘述。
S204、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
在S203之后，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S205，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S203之后，已完成子块融合候选列表的确定。
S205、获取planar帧间预测模式对应的第一候选运动矢量，若该第一候选运动矢量可用，则将该第一候选运动矢量添加至子块融合候选列表。
对于获取planar帧间预测模式对应的候选运动矢量的方法可以参见上述实施例中的相关描述，此处不再赘述。
应理解，在S201中，若向子块融合候选列表中添加了第二候选运动矢量，且在S205中向子块融合候选列表中添加了第一候选运动矢量，则子块融合候选列表中的第一候选运动矢量排列在第二候选运动矢量之后。
应理解，在S203中，若向子块融合候选列表中添加了第三候选运动矢量，且在S205中向子块融合候选列表中添加了第一候选运动矢量，则子块融合候选列表中的第一候选运动矢量排列在第三候选运动矢量之后。
S206、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
在S205之后，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S207，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S205之后，已完成子块融合候选列表的确定。
S207、获取继承的控制点运动矢量预测模式对应的第三候选运动矢量，若该第三候选运动矢量可用且不重复，则将该第三候选运动矢量添加至子块融合候选列表。
S208、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
在S207之后，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S209，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量， 则无需再向子块融合候选列表中添加候选运动矢量，即在S207之后，已完成子块融合候选列表的确定。
S209、获取构造的控制点运动矢量预测模式对应的第四候选运动矢量，若该第四候选运动矢量可用，则将该第四候选运动矢量添加至子块融合候选列表。
本申请实施例中，可以向子块融合候选列表中添加的第四候选运动矢量的数量最多为6个，具体的，结合上述S208可以确定子块融合候选列表中还需存入几个第四候选运动矢量。
对于获取构造的控制点运动矢量预测模式对应的候选运动矢量的方法可以参见上述实施例中的相关描述，此处不再赘述。
S210、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
在S209之后，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S211，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S209之后，已完成子块融合候选列表的确定
S211、向子块融合候选列表中添加零运动矢量，使得子块融合候选列表中的候选运动矢量的数量等于预设数量。
可选的，本申请实施例中，根据性能测试结果，对待处理图像块采用planar帧间预测模式的预测结果与采用继承的控制点运动矢量预测模式的预测结果的性能(效果)相当，因此在上述实施例中，planar帧间预测模式可以在继承的控制点运动矢量预测模式之前(上述S203中向子块融合候选列表添加0个第三候选运动矢量)；planar帧间预测模式可以在继承的控制点运动矢量预测模式之后(上述S207中向子块融合候选列表添加0个第三候选运动矢量)；planar帧间预测模式可以在两个继承的控制点运动矢量预测模式之间，此时，S203与S207中向子块融合候选列表添加的第三候选运动矢量的数量之和小于或者等于2。
应注意，上述S203或S207中向子块融合候选列表添加0个第三候选运动矢量，即不执行S203或不执行S207的动作。
第二种方法：候选预测模式包括ATMVP，继承的控制点运动矢量预测模式以及planar帧间预测模式，并且这几种候选预测模式的遍历顺序以及根据每种预测模式可获得的候选运动矢量的最大数量可参见表7。
表7
Figure PCTCN2019116115-appb-000020
如图12所示，结合上述表7，本申请实施例提供的帧间预测方法可以包括S301-S307：
S301、获取ATMVP模式对应的第二候选运动矢量，若该第二候选运动矢量可用，则将其添加至子块融合候选列表。
S302、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
本申请实施例中，子块融合候选列表中的候选运动矢量的预设数量为小于5的正整数，例如，候选运动矢量的数量可以为1，2，3或4。
本申请实施例中，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S303，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S301之后，已完成子块融合候选列表的确定。
S303、获取继承的控制点运动矢量预测模式对应的第三候选运动矢量，若该第三候选运动矢量可用，则将该第三候选运动矢量添加至子块融合候选列表。
本申请实施例中，可以向子块融合候选列表中添加的第三候选运动矢量的数量最多为1个，解码端获取到的第三候选运动矢量可用，则将该第三候选运动矢量添加至子块融合候选列表。
S304、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
在S303之后，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S305，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S303之后，已完成子块融合候选列表的确定。
S305、获取planar帧间预测模式对应的第一候选运动矢量，若该第一候选运动矢量可用，则将该第一候选运动矢量添加至子块融合候选列表。
应理解，在S301中，若向子块融合候选列表中添加了第二候选运动矢量，且在S305中向子块融合候选列表中添加了第一候选运动矢量，则子块融合候选列表中的第一候选运动矢量排列在第二候选运动矢量之后。
应理解，在S303中，若向子块融合候选列表中添加了第三候选运动矢量，且在S305中向子块融合候选列表中添加了第一候选运动矢量，则子块融合候选列表中的第一候选运动矢量排列在第三候选运动矢量之后。
S306、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
在S305之后，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S307，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S205之后，已完成子块融合候选列表的确定。
S307、获取继承的控制点运动矢量预测模式对应的第三候选运动矢量，若该第三候选运动矢量可用，则将该第三候选运动矢量添加至子块融合候选列表。
需要说明的是，本申请实施例中，在上述S303中向子块融合候选列表中添加的第三候选运动矢量与S307中向子块融合候选列表中添加的第三候选运动矢量的数量之和小于或者等于2。
对于S301-S307中其他内容的描述，可以参见上述S201-S211中的相关描述，此处不再赘述。
第三种方法：候选预测模式包括ATMVP，继承的控制点运动矢量预测模式以及planar帧间预测模式，并且这几种候选预测模式的遍历顺序以及根据每种预测模式可获得的候选运动矢量的最大数量可参见表8。
表8
Figure PCTCN2019116115-appb-000021
如图13所示，结合上述表8，本申请实施例提供的帧间预测方法可以包括S401-S405：
S401、获取ATMVP模式对应的第二候选运动矢量，若该第二候选运动矢量可用，则将其添加至子块融合候选列表。
S402、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
本申请实施例中，子块融合候选列表中的候选运动矢量的预设数量为小于5的正整数，例如，候选运动矢量的数量可以为1，2，3或4。
本申请实施例中，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S403，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S401之后，已完成子块融合候选列表的确定。
S403、获取继承的控制点运动矢量预测模式对应的第三候选运动矢量，若该第三候选运动矢量可用且不重复，则将该第三候选运动矢量添加至子块融合候选列表。
本申请实施例中，可以向子块融合候选列表中添加的第三候选运动矢量的数量最多为1个或者2个，解码端获取到第三候选运动矢量之后，检查其可用性并剔除重复项(若只有1个第三候选运动矢量，则无需执行剔除重复项的动作)之后，向子块融合候选列表中添加指定数量的第三候选运动矢量。同理，该指定数量是根据预设数量、第二候选运动矢量是否可用以及第三候选运动矢量的最大数量确定的，通过S402可以确定需要向子块融合候选列表中添加几个第三候选运动矢量。
S404、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
在S403之后，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S405，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S403之后，已完成子块融合候选列表的确定。
S405、获取planar帧间预测模式对应的第一候选运动矢量，若该第一候选运动矢量可用，则将该第一候选运动矢量添加至子块融合候选列表。
应理解，在S401中，若向子块融合候选列表中添加了第二候选运动矢量，且在S405中向子块融合候选列表中添加了第一候选运动矢量，则子块融合候选列表中的第一候选运动矢量排列在第二候选运动矢量之后。
应理解，在S403中，若向子块融合候选列表中添加了第三候选运动矢量，且在 S205中向子块融合候选列表中添加了第一候选运动矢量，则子块融合候选列表中的第一候选运动矢量排列在第三候选运动矢量之后。
对于S401-S305中其他内容的描述，可以参见上述S201-S211中的相关描述，此处不再赘述。
第四种方法：候选预测模式包括ATMVP，继承的控制点运动矢量预测模式、构造的控制点运动矢量预测模式、planar帧间预测模式以及零运动矢量预测模式，并且这几种候选预测模式的遍历顺序以及根据每种预测模式可获得的候选运动矢量的最大数量可参见表9。
表9
Figure PCTCN2019116115-appb-000022
如图14所示，结合上述表9，本申请实施例提供的帧间预测方法可以包括S501-S511：
S501、获取ATMVP模式对应的第二候选运动矢量，若该第二候选运动矢量可用，则将其添加至子块融合候选列表。
S502、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
本申请实施例中，子块融合候选列表中的候选运动矢量的预设数量为小于或者等于5的正整数，例如，候选运动矢量的数量可以为1，2，3、4或5。
本申请实施例中，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S503，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S501之后，已完成子块融合候选列表的确定。
S503、获取继承的控制点运动矢量预测模式对应的第三候选运动矢量，若该第三候选运动矢量可用且不重复，则将该第三候选运动矢量添加至子块融合候选列表。
本申请实施例中，可以向子块融合候选列表中添加的第三候选运动矢量的数量最多为2个，解码端获取到2个第三候选运动矢量之后，检查其可用性并剔除重复项之后，向子块融合候选列表中添加指定数量的第三候选运动矢量。同理，该指定数量是根据预设数量、第二候选运动矢量是否可用以及第三候选运动矢量的最大数量确定的，通过S502可以确定需要向子块融合候选列表中添加几个第三候选运动矢量。
S504、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
在S503之后，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执 行下述S505，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S303之后，已完成子块融合候选列表的确定。
S505、获取构造的控制点运动矢量预测模式对应的第四候选运动矢量，若第四候选运动矢量可用，则将该第四候选运动矢量添加至子块融合候选列表。
本申请实施例中，可以向子块融合候选列表中添加的第四候选运动矢量的数量最多为6个，解码端获取到6个第三候选运动矢量之后，检查其可用性之后，向子块融合候选列表中添加指定数量的第四候选运动矢量。同理，该指定数量是根据预设数量、添加的第三候选运动矢量的数量以及第四候选运动矢量的最大数量确定的，通过S504可以确定需要向子块融合候选列表中添加几个第四候选运动矢量。
S506、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
在S505之后，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S507，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S505之后，已完成子块融合候选列表的确定。
S507、获取planar帧间预测模式对应的第一候选运动矢量，若该第一候选运动矢量可用，则将该第一候选运动矢量添加至子块融合候选列表。
应理解，在S501中，若向子块融合候选列表中添加了第二候选运动矢量，且在S507中向子块融合候选列表中添加了第一候选运动矢量，则子块融合候选列表中的第一候选运动矢量排列在第二候选运动矢量之后。
应理解，在S503中，若向子块融合候选列表中添加了第三候选运动矢量，且在S507中向子块融合候选列表中添加了第一候选运动矢量，则子块融合候选列表中的第一候选运动矢量排列在第三候选运动矢量之后。
应理解，在S505中，若向子块融合候选列表中添加了第四候选运动矢量，且在S507中向子块融合候选列表中添加了第一候选运动矢量，则子块融合候选列表中的第一候选运动矢量排列在第四候选运动矢量之后。
S508、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
在S507之后，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S509，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S507之后，已完成子块融合候选列表的确定。
S509、获取构造的控制点运动矢量预测模式对应的第四候选运动矢量，若第四候选运动矢量可用，则将该第四候选运动矢量添加至子块融合候选列表。
可选的，本申请实施例中，在上述S505中向子块融合候选列表中添加的第三候选运动矢量与S509中向子块融合候选列表中添加的第三候选运动矢量的总数量小于或者等于6。
对于获取构造的控制点运动矢量预测模式对应的候选运动矢量的方法可以参见上述实施例中的相关描述，此处不再赘述。
S510、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
在S509之后，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S511，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S509之后，已完成子块融合候选列表的确定。
S511、向子块融合候选列表中添加零运动矢量，使得子块融合候选列表中的候选运动矢量的数量等于预设数量。
对于S501-S511中其他内容的描述，可以参见上述S201-S211中的相关描述，此处不再赘述。
第五种方法：候选预测模式包括ATMVP，继承的控制点运动矢量预测模式、构造的控制点运动矢量预测模式以及零运动矢量预测模式，并且这几种候选预测模式的遍历顺序以及根据每种预测模式可获得的候选运动矢量的最大数量可参见表10。
表10
Figure PCTCN2019116115-appb-000023
如图15所示，结合上述表10，本申请实施例提供的帧间预测方法可以包括S601-S607：
S601、获取ATMVP模式对应的第二候选运动矢量，若该第二候选运动矢量可用，则将其添加至子块融合候选列表。
S602、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
本申请实施例中，子块融合候选列表中的候选运动矢量的预设数量为小于5的正整数，例如，候选运动矢量的数量可以为1，2，3或4。
本申请实施例中，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S603，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S601之后，已完成子块融合候选列表的确定。
S603、获取继承的控制点运动矢量预测模式对应的第三候选运动矢量，若该第三候选运动矢量可用且不重复，则将该第三候选运动矢量添加至子块融合候选列表。
本申请实施例中，可以向子块融合候选列表中添加的第三候选运动矢量的数量最多为1个或者2个，解码端获取到第三候选运动矢量之后，检查其可用性并剔除重复项(若只有1个第三候选运动矢量，则无需执行剔除重复项的动作)之后，向子块融合候选列表中添加指定数量的第三候选运动矢量。同理，该指定数量是根据预设数量、第二候选运动矢量是否可用以及第三候选运动矢量的最大数量确定的，通过S402可以确定需要向子块融合候选列表中添加几个第三候选运动矢量。
S604、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
在S603之后，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S605，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S603之后，已完成子块融合候选列表的确定。
S605、获取构造的控制点运动矢量预测模式对应的第四候选运动矢量，若该第四候选运动矢量可用，则将该第四候选运动矢量添加至子块融合候选列表。
S606、确定子块融合候选列表中的候选运动矢量的数量是否小于预设数量。
在S605之后，若子块融合候选列表中的候选运动矢量的数量小于预设数量，则执行下述S607，若子块融合候选列表中的候选运动矢量的数量达到(即等于)预设数量，则无需再向子块融合候选列表中添加候选运动矢量，即在S605之后，已完成子块融合候选列表的确定。
S607、向子块融合候选列表中添加零运动矢量，使得子块融合候选列表中的候选运动矢量的数量等于预设数量。
对于S601-S607中其他内容的描述，可以参见上述S201-S211中的相关描述，此处不再赘述。
综上所述，通过上述不同的方法确定出子块融合候选列表，基于该子块融合候选列表对待处理图像块进行预测方法均类似，具体参见上述实施例中的相关描述。
可选的，本申请实施例中，解码端也可以无需构建完整的子块融合候选列表，在解码端可以获知编码端在编码过程中的所采用的预测模式以及所采用的预测模式的顺序的情况下(预测模式的顺序与子块融合候选列表中的候选运动矢量的顺序一致，解码端解析码流得到目标候选运动矢量的索引之后，解码端可以根据目标候选运动矢量的索引以及预测模式的顺序确定目标候选运动矢量，从而基于该目标候选运动矢量对待处理图像块进行预测。
示例性的，若解码端已知编码端构建的子块融合候选列表中包括3个候选运动矢量，并且第1个候选运动矢量对应的预测模式为ATMVP模式，第2个候选运动矢量对应的预测模式为继承的控制点运动矢量预测模式，第3个候选运动矢量对应的预测模式为planar帧间预测模式，解码端解析的目标候选运动矢量的索引为3，那么解码端即可获知索引3对应的预测模式为planar帧间预测模式，该解码端直接获取planar帧间预测模式对应的候选运动矢量，并基于该候选运动矢量对待处理图像块进行预测，如此，解码端无需确定子块融合候选列表中的第1个候选运动矢量和第2个候选运动矢量，能够显著提高解码效率。
基于与上述方法相同的发明构思，如图16所示，本申请实施例还提供了一种视频图像解码装置1000，该视频图像解码装置1000包括确定模块1001、解析模块1002以及预测模块1003，其中：
确定模块1001用于待处理图像块的子块融合候选列表，该子块融合候选列表包括根据多个候选预测模式获得的至少一个候选运动矢量，该多个候选预测模式中包括planar帧间预测模式；解析模块1002用于从码流中解析索引信息，该索引信息用于指示子块融合候选列表中的目标候选运动矢量；预测模块1003用于基于上述索引信息指示的目标候选运动矢量，得到待处理图像块的预测值。
可选的，上述多个候选预测模式分别获得的至少一个候选运动矢量包括：第一候选运动矢量、第二候选运动矢量、第三候选运动矢量、第四候选运动矢量或第五候选运动矢量，其中，第一候选运动矢量根据planar帧间预测模式获得，第二候选运动矢量根据ATMVP模式获得，第三候选运动矢量根据继承的控制点运动矢量预测模式获得，第四候选运动矢量根据构造的控制点运动预测模式获得，第五候选运动矢量为零运动矢量。
可选的，当子块融合候选列表中存在第一候选运动矢量和第二候选运动矢量时，第一候选运动矢量排列在第二候选运动矢量之后。
可选的，当子块融合候选列表中存在第一候选运动矢量和第三候选运动矢量时，第一候选运动矢量排列在第三候选运动矢量之后。
可选的，当子块融合候选列表中存在第一候选运动矢量和第四候选运动矢量时，第一候选运动矢量排列在第四候选运动矢量之后。
可选的，子块融合候选列表中的候选运动矢量的数量为小于或等于5的正整数。
可选的，子块融合列表中排列在先的候选运动矢量对应的索引的码字长度小于或等于排列在后的候选运动矢量对应的索引的码字长度。
还需要说明的是，确定模块1001、解析模块1002和预测模块1003的具体实现过程可参考图10至图15的实施例的详细描述，为了说明书的简洁，这里不再赘述。
在上述实施例中，可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。当使用软件程序实现时，可以全部或部分地以计算机程序产品的形式实现。该计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行该计算机指令时，全部或部分地产生按照本申请实施例中的流程或功能。该计算机可以是通用计算机、专用计算机、计算机网络或者其他可编程装置。该计算机指令可以存储在计算机可读存储介质中，或者从一个计算机可读存储介质向另一个计算机可读存储介质传输，例如，该计算机指令可以从一个网站站点、计算机、服务器或数据中心通过有线(例如同轴电缆、光纤、数字用户线(digital subscriber line，DSL))方式或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心传输。该计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包括一个或多个可用介质集成的服务器、数据中心等数据存储设备。该可用介质可以是磁性介质(例如，软盘、磁盘、磁带)、光介质(例如，数字视频光盘(digital video disc，DVD))、或者半导体介质(例如固态硬盘(solid state drives，SSD))等。
通过以上的实施方式的描述，所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，仅以上述各功能模块的划分进行举例说明，实际应用中，可以根据需要而将上述功能分配由不同的功能模块完成，即将装置的内部结构划分成不同的功能模块，以完成以上描述的全部或者部分功能。上述描述的系统，装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统，装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述模块或单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或 不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。
所述集成的单元如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的全部或部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)或处理器执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：快闪存储器、移动硬盘、只读存储器、随机存取存储器、磁碟或者光盘等各种可以存储程序代码的介质。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何在本申请揭露的技术范围内的变化或替换，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以所述权利要求的保护范围为准。

Claims (15)

  1. 一种帧间预测方法，其特征在于，包括：
    确定待处理图像块的子块融合候选列表，所述子块融合候选列表包括根据多个候选预测模式获得的至少一个候选运动矢量，所述多个候选预测模式中包括平面planar帧间预测模式；
    从码流中解析索引信息，所述索引信息用于指示所述子块融合候选列表中的目标候选运动矢量；
    基于所述索引信息指示的目标候选运动矢量，得到所述待处理图像块的预测值。
  2. 根据权利要求1所述的方法，其特征在于，
    所述多个候选预测模式分别获得的至少一个候选运动矢量包括：第一候选运动矢量、第二候选运动矢量、第三候选运动矢量、第四候选运动矢量或第五候选运动矢量，其中，所述第一候选运动矢量根据所述planar帧间预测模式获得，所述第二候选运动矢量根据高级时域运动矢量预测ATMVP模式获得，所述第三候选运动矢量根据继承的控制点运动矢量预测模式获得，所述第四候选运动矢量根据构造的控制点运动矢量预测模式获得，所述第五候选运动矢量为零运动矢量。
  3. 根据权利要求1或2所述的方法，其特征在于，当所述子块融合候选列表中存在第一候选运动矢量和第二候选运动矢量时，所述第一候选运动矢量排列在所述第二候选运动矢量之后。
  4. 根据权利要求1或2所述的方法，其特征在于，当所述子块融合候选列表中存在第一候选运动矢量和第三候选运动矢量时，所述第一候选运动矢量排列在所述第三候选运动矢量之后。
  5. 根据权利要求1或2所述的方法，其特征在于，当所述子块融合候选列表中存在第一候选运动矢量和第四候选运动矢量时，所述第一候选运动矢量排列在所述第四候选运动矢量之后。
  6. 根据权利要求1至5任一项所述的方法，其特征在于，
    所述子块融合候选列表中的候选运动矢量的数量为小于或等于5的正整数。
  7. 根据权利要求1至6任一项所述的方法，其特征在于，
    所述子块融合列表中排列在先的候选运动矢量对应的索引的码字长度小于或等于排列在后的候选运动矢量对应的索引的码字长度。
  8. 一种帧间预测装置，其特征在于，包括：
    确定模块，用于待处理图像块的子块融合候选列表，所述子块融合候选列表包括根据多个候选预测模式获得的至少一个候选运动矢量，所述多个候选预测模式中包括平面planar帧间预测模式；
    解析模块，用于从码流中解析索引信息，所述索引信息用于指示所述子块融合候选列表中的目标候选运动矢量；
    预测模块，用于基于所述索引信息指示的目标候选运动矢量，得到所述待处理图像块的预测值。
  9. 根据权利要求8所述的装置，其特征在于，
    所述多个候选预测模式分别获得的至少一个候选运动矢量包括：第一候选运动矢 量、第二候选运动矢量、第三候选运动矢量、第四候选运动矢量或第五候选运动矢量，其中，所述第一候选运动矢量根据所述planar帧间预测模式获得，所述第二候选运动矢量根据高级时域运动矢量预测ATMVP模式获得，所述第三候选运动矢量根据继承的控制点运动矢量预测模式获得，所述第四候选运动矢量根据构造的控制点运动预测模式获得，所述第五候选运动矢量为零运动矢量。
  10. 根据权利要求8或9所述的装置，其特征在于，当所述子块融合候选列表中存在第一候选运动矢量和第二候选运动矢量时，所述第一候选运动矢量排列在所述第二候选运动矢量之后。
  11. 根据权利要求8或9所述的装置，其特征在于，当所述子块融合候选列表中存在第一候选运动矢量和第三候选运动矢量时，所述第一候选运动矢量排列在所述第三候选运动矢量之后。
  12. 根据权利要求8或9所述的装置，其特征在于，当所述子块融合候选列表中存在第一候选运动矢量和第四候选运动矢量时，所述第一候选运动矢量排列在所述第四候选运动矢量之后。
  13. 根据权利要求8至12任一项所述的装置，其特征在于，
    所述子块融合候选列表中的候选运动矢量的数量为小于或等于5的正整数。
  14. 根据权利要求8至13任一项所述的装置，其特征在于，
    所述子块融合列表中排列在先的候选运动矢量对应的索引的码字长度小于或等于排列在后的候选运动矢量对应的索引的码字长度。
  15. 一种视频解码设备，其特征在于，包括：相互耦合的非易失性存储器和处理器，所述处理器调用存储在所述存储器中的程序代码以执行如权利要求1-7任一项所述的方法。
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CN103299642A (zh) * 2011-01-07 2013-09-11 Lg电子株式会社 编码和解码图像信息的方法和使用该方法的装置
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CN103299642A (zh) * 2011-01-07 2013-09-11 Lg电子株式会社 编码和解码图像信息的方法和使用该方法的装置
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