WO2020134817A1 - 预测模式确定方法、装置及编码设备和解码设备 - Google Patents

预测模式确定方法、装置及编码设备和解码设备 Download PDF

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WO2020134817A1
WO2020134817A1 PCT/CN2019/121312 CN2019121312W WO2020134817A1 WO 2020134817 A1 WO2020134817 A1 WO 2020134817A1 CN 2019121312 W CN2019121312 W CN 2019121312W WO 2020134817 A1 WO2020134817 A1 WO 2020134817A1
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block
image sub
mode
prediction mode
prediction
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PCT/CN2019/121312
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English (en)
French (fr)
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杨海涛
赵寅
张恋
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华为技术有限公司
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Priority claimed from CN201910222962.4A external-priority patent/CN111385572B/zh
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP19902416.7A priority Critical patent/EP3893505A4/en
Publication of WO2020134817A1 publication Critical patent/WO2020134817A1/zh
Priority to US17/357,684 priority patent/US11895297B2/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/103—Selection of coding mode or of prediction mode
    • H04N19/107—Selection of coding mode or of prediction mode between spatial and temporal predictive coding, e.g. picture refresh
    • 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
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/119—Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
    • 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
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/124—Quantisation
    • 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
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/13—Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
    • 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
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
    • H04N19/157—Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter
    • H04N19/159—Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
    • 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
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
    • H04N19/17—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object
    • H04N19/176—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a block, e.g. a macroblock
    • 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
    • H04N19/85—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using pre-processing or post-processing specially adapted for video compression
    • 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
    • H04N19/90—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using coding techniques not provided for in groups H04N19/10-H04N19/85, e.g. fractals
    • H04N19/96—Tree coding, e.g. quad-tree coding

Definitions

  • the present application relates to the field of video coding, and in particular, to a prediction mode determination method, device, coding device, and decoding device.
  • Video encoding (video encoding and decoding) is widely used in digital video applications, such as broadcast digital TV, video dissemination on the Internet and mobile networks, real-time conversation applications such as video chat and video conferencing, DVD and Blu-ray discs, video content acquisition and editing systems And security applications for camcorders.
  • Video coding standards include MPEG-1 video, MPEG-2 video, ITU-T H.262/MPEG-2, ITU-T H.263, ITU-T H.264/MPEG-4 Part 10 Advanced Video Coding ( Advanced Video Coding (AVC), ITU-T H.265/High Efficiency Video Coding (HEVC)... and extensions of such standards, such as scalability and/or 3D (three-dimensional) extensions.
  • AVC Advanced Video Coding
  • HEVC High Efficiency Video Coding
  • extensions of such standards such as scalability and/or 3D (three-dimensional) extensions.
  • LCU Large Coding Unit
  • CU Coding Unit
  • BT binary tree
  • EQT Extended Quad Tree
  • HBT Horizontal Extended Quad Tree
  • VEQT Vertical Extended Quad Tree
  • Embodiments of the present application provide a prediction mode determination method, device, and encoding device and decoding device. In the process of determining the prediction mode of the current image block according to the code stream of the current image block, there is no need to parse all code streams, which is convenient for hardware pipeline processing .
  • the present application provides a method for determining a prediction mode, including: determining a division method of a current image block; determining whether a first image satisfying a preset condition will be obtained after dividing the current image block by using the division method Sub-blocks; if it is determined that the first image sub-block will be obtained after division, the current image block is divided using the division method to obtain multiple image sub-blocks, the multiple image sub-blocks including the first Image sub-blocks; it is determined that the multiple image sub-blocks use the same prediction mode, and the prediction modes of the multiple image sub-blocks are both intra prediction modes or inter prediction modes.
  • the preset condition includes that the area of the first image sub-block is less than or equal to a set threshold.
  • the determining that the multiple image sub-blocks use the same prediction mode includes: parsing the code stream of the current image block to determine the prediction mode of the second image sub-block, the second The image sub-block is the first image sub-block determined as the coding unit CU among the plurality of image sub-blocks according to the processing order, and the prediction mode of the second image sub-block is the intra prediction mode or the inter frame Prediction mode; determining prediction modes of other image sub-blocks in the plurality of image sub-blocks except the second image sub-block according to the prediction mode of the second image sub-block, the prediction modes of the other image sub-blocks The same as the prediction mode of the second image sub-block is the intra prediction mode or the inter prediction mode.
  • the inter prediction mode includes a skip mode, a direct mode, or a normal inter mode.
  • the determining, according to the prediction mode of the second image sub-block, prediction modes of other image sub-blocks in the plurality of image sub-blocks except the second image sub-block includes: : When the prediction mode of the second image sub-block is the inter-prediction mode, parse the code stream to obtain the skip mode identifier of the other image sub-blocks, and determine the skip mode identifier according to the skip mode identifier Whether the prediction mode of other image sub-blocks is the skip mode; if the skip mode indicator indicates that the skip mode is used, it is determined that the prediction mode of the other image sub-blocks is the skip mode.
  • the determining a prediction mode of other image sub-blocks in the plurality of image sub-blocks except the second image sub-block according to the prediction mode of the second image sub-block includes: if the skip mode indicator indicates that the skip mode is not used, analyzing the code stream to obtain the direct mode identifier of the other image sub-blocks, and judging the other image sub-blocks according to the direct mode identifier Whether the prediction mode of is the direct mode; if the direct mode indicator indicates that the direct mode is used, determine that the prediction mode of the other image sub-blocks is the direct mode; if the direct mode indicator indicates that the direct mode is not used In the direct mode, it is determined that the prediction mode of the other image sub-blocks is the normal inter mode.
  • the determining, according to the prediction mode of the second image sub-block, prediction modes of other image sub-blocks in the plurality of image sub-blocks except the second image sub-block includes: : When the prediction mode of the second image sub-block is the intra prediction mode, parse the code stream to determine that the prediction mode of the other image sub-block is one of the intra prediction modes.
  • the determining whether the current image block is obtained by dividing the current image block by using the division method includes: if the area of the current image block If the following conditions are met, the first image sub-block will be obtained after the division is determined: when the division mode is a binary tree BT division mode, sizeC/2 is less than S, sizeC is the area of the current image block, and S is a preset Area threshold; or, when the division method is a quadtree QT division method, sizeC/4 is less than S; or, when the division method is an extended quadtree EQT division method, sizeC/4 is less than S.
  • whether the first image sub-block satisfying a preset condition will be obtained further includes: To obtain the first image sub-block, use the division method to divide the current image block to obtain a plurality of image sub-blocks, and determine the division method of the plurality of image sub-blocks respectively, for each of the image sub-blocks The blocks are divided separately using corresponding division methods.
  • the parsing the code stream of the current image block to determine the prediction mode of the second image sub-block includes: parsing the code stream to obtain the skip mode identifier of the second image sub-block And determine whether the prediction mode of the second image sub-block is the skip mode according to the skip mode flag; if the skip mode flag indicates that the skip mode is used, determine the second image The prediction mode of the sub-block is the skip mode.
  • the parsing the code stream of the current image block to determine the prediction mode of the second image sub-block further includes: if the skip mode identifier indicates that the skip mode is not used, then Parse the code stream to obtain the direct mode identifier of the second image sub-block, and determine whether the prediction mode of the second image sub-block is the direct mode according to the direct mode identifier; if the direct mode identifier indicates Using the direct mode, it is determined that the prediction mode of the second image sub-block is the direct mode.
  • the parsing the code stream of the current image block to determine the prediction mode of the second image sub-block further includes: if the direct mode identifier indicates that the direct mode is not used, then parsing The prediction mode identifier of the second image sub-block in the code stream, and determining whether the prediction mode of the second image sub-block is the intra prediction mode according to the prediction mode identifier; if the prediction mode identifier indicates the use In the intra prediction mode, it is determined that the prediction mode of the second image sub-block is the intra prediction mode; if the prediction mode flag indicates the use of a normal inter mode, the determination of the second image sub-block The prediction mode is the normal inter mode.
  • the other image sub-blocks are determined based on the prediction mode of one of the image sub-blocks divided by the current image block, especially those with a smaller area
  • the prediction mode of the image sub-blocks eliminates the need to parse all code streams, and uses the same prediction mode as other image sub-blocks for image sub-blocks with a small area, which is convenient for hardware pipeline processing.
  • the present application provides a prediction mode determination device, including: a determination module for determining a division method of a current image block; and a determination module for determining whether to divide the current image block using the division method A first image sub-block that meets a preset condition will be obtained; a dividing module is used to divide the current image block by using the dividing method to obtain multiple images if it is judged that the first image sub-block will be obtained after dividing Sub-blocks, the plurality of image sub-blocks includes the first image sub-block; the prediction module is used to determine that the plurality of image sub-blocks use the same prediction mode, and the prediction modes of the plurality of image sub-blocks are the same Intra prediction mode or inter prediction mode.
  • the preset condition includes that the area of the first image sub-block is less than or equal to a set threshold.
  • the prediction module is specifically configured to parse the code stream of the current image block to determine the prediction mode of the second image sub-block, and the second image sub-block is the multiple image sub-blocks.
  • the first image subblock in the block determined as the coding unit CU according to the processing order, and the prediction mode of the second image subblock is the intra prediction mode or the inter prediction mode; according to the second image sub
  • the prediction mode of the block determines the prediction mode of the image subblocks other than the second image subblock among the plurality of image subblocks, the prediction mode of the other image subblocks and the prediction of the second image subblock
  • the modes are the intra prediction mode or the inter prediction mode.
  • the inter prediction mode includes a skip mode, a direct mode, or a normal inter mode.
  • the prediction module is specifically configured to parse the code stream to obtain the other image subblocks when the prediction mode of the second image subblock is the inter prediction mode Skip mode identifier, and determine whether the prediction mode of the other image sub-blocks is the skip mode according to the skip mode identifier; if the skip mode identifier indicates that the skip mode is used, determine The prediction mode of other image sub-blocks is the skip mode.
  • the prediction module is further configured to parse the code stream to obtain the direct mode identifier of the other image sub-blocks if the skip mode identifier indicates that the skip mode is not used And determine whether the prediction mode of the other image sub-blocks is the direct mode according to the direct mode identifier; if the direct mode identifier indicates the use of the direct mode, determine the prediction mode of the other image sub-blocks as The direct mode; if the direct mode identifier indicates that the direct mode is not used, determining that the prediction mode of the other image sub-blocks is the normal inter mode.
  • the prediction module is specifically configured to, when the prediction mode of the second image sub-block is the intra prediction mode, parse the code stream to determine the performance of the other image sub-blocks
  • the prediction mode is one of the intra prediction modes.
  • the judgment module is specifically configured to obtain the first image sub-block after determining the division if the area of the current image block satisfies the following conditions: when the division method is a binary tree In the BT division method, sizeC/2 is less than S, sizeC is the area of the current image block, and S is a preset area threshold; or, when the division method is a quadtree QT division method, sizeC/4 is less than S; Or, when the division method is an extended quadtree EQT division method, sizeC/4 is smaller than S.
  • the dividing module is further configured to divide the current image block by using the dividing method to obtain multiple images if it is determined that the first image sub-block will not be obtained after dividing Sub-blocks, and separately determine the division manner of the plurality of image sub-blocks, and use the corresponding division manner to divide the image sub-blocks respectively.
  • the prediction module is specifically configured to parse the code stream to obtain a skip mode identifier of the second image sub-block, and determine the second image according to the skip mode identifier Whether the prediction mode of the sub-block is the skip mode; if the skip mode flag indicates that the skip mode is used, it is determined that the prediction mode of the second image sub-block is the skip mode.
  • the prediction module is further configured to analyze the code stream to obtain the direct mode of the second image sub-block if the skip mode indicator indicates that the skip mode is not used Flag, and determine whether the prediction mode of the second image sub-block is the direct mode according to the direct mode flag; if the direct mode flag indicates the use of the direct mode, determine the The prediction mode is the direct mode.
  • the prediction module is further configured to parse the prediction mode identifier of the second image sub-block of the code stream if the direct mode identifier indicates that the direct mode is not used, and Determine whether the prediction mode of the second image subblock is the intra prediction mode according to the prediction mode identifier; if the prediction mode identifier indicates the use of the intra prediction mode, determine the second image subblock The prediction mode of is the intra prediction mode; if the prediction mode indicator indicates that a normal inter mode is used, it is determined that the prediction mode of the second image subblock is the normal inter mode.
  • the present application provides a video encoding device, including: a non-volatile memory and a processor coupled to each other, and the processor calls program codes stored in the memory to perform any of the foregoing first aspects A method described.
  • the present application provides a video decoding device, including: a non-volatile memory and a processor coupled to each other, and the processor calls program codes stored in the memory to perform any of the above-mentioned first aspects A method described.
  • 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.
  • FIG. 1A is a block diagram of an example of a video encoding and decoding system 10 for implementing embodiments of the present application;
  • FIG. 1B is a block diagram of an example of a video decoding system 40 for implementing embodiments 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 a division manner for implementing a binary tree, a quad tree, and an extended quad tree according to an embodiment of the present application;
  • FIG. 7 is a schematic diagram of QT-MTT division used to implement the embodiment of the present application.
  • FIG. 8 is a flowchart illustrating a prediction mode determination method according to an embodiment of the present application.
  • FIG. 9 is a flowchart illustrating a prediction mode determination method according to an embodiment of the present application.
  • FIG. 10 is a flowchart illustrating a prediction mode determination method according to an embodiment of the present application.
  • FIG. 11 is a schematic block diagram of a prediction mode determining apparatus 1100 in an embodiment of the present application.
  • the corresponding device may contain 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.
  • the technical solutions involved in the embodiments of the present application may not only be applied to existing video coding standards (such as H.264, High Efficiency Video Coding (HEVC), and other standards), but may also be applied to future video coding In the standard (such as H.266 standard), or may be used in the digital audio and video codec (Audio Video Coding Standard Workgroup of China, AVS) technical standards, such as AVS3.
  • HEVC High Efficiency Video Coding
  • AVS Analog Video Coding Standard Workgroup of China
  • 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.
  • Video coding is performed in units of blocks.
  • the concept of blocks is further expanded.
  • macroblock macroblock, MB
  • HEVC high-efficiency video coding
  • 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
  • the video coding standard divides a frame of image into non-overlapping coding tree units (Coding Tree Unit, CTU), and then divides a CTU into several sub-nodes. These sub-nodes can be processed according to a quad tree (QT) It is divided into smaller child nodes, and the smaller child nodes can continue to be divided to form a quadtree structure. If the node is no longer divided, it is called CU.
  • the CU is the basic unit for dividing and coding the coded 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. However, regardless of CU, PU or TU, they all belong to the concept of block (or image block) in essence.
  • the CTU is split into multiple CUs by using a quadtree structure represented as a coding tree.
  • a decision is made at the CU level whether to use inter-picture (temporal) or intra-picture (spatial) prediction to encode picture regions.
  • Each CU can be further split into one, two, or four PUs according to the PU split type.
  • the same prediction process is applied within a PU, and related information is transmitted to the decoder on the basis of the PU.
  • the CU may be divided into TUs according to other quadtree structures similar to the coding tree used for CU.
  • quad-tree and binary-tree (Quad-tree and binary tree, QTBT) split frames are used to split the coding blocks.
  • the CU may have a square or rectangular shape.
  • the image block to be encoded in the current encoded image may be referred to as the current block.
  • the reference block is a block that provides a reference signal for the current block, where the reference signal represents a pixel value within the image block.
  • the block in the reference image that provides the prediction signal for the current block may be a prediction block, where the prediction signal represents a pixel value or a sample value or a sample signal within the prediction block. For example, after traversing multiple reference blocks, the best reference block is found. This best reference block will provide a prediction for the current block. This block is called a prediction block.
  • the original video picture can be reconstructed, that is, the reconstructed video picture has the same quality as the original video picture (assuming no transmission loss or other data loss during storage or transmission).
  • further compression is performed by, for example, quantization to reduce the amount of data required to represent the video picture, but the decoder side cannot fully reconstruct the video picture, that is, the quality of the reconstructed video picture is better than the original video picture. The quality is lower or worse.
  • Several video coding standards of H.261 belong to "lossy hybrid video codec” (ie, combining spatial and temporal prediction in the sample domain with 2D transform coding for applying quantization in the transform domain).
  • Each picture of a video sequence is usually divided into non-overlapping block sets, which are usually encoded at the block level.
  • the encoder side usually processes the encoded video at the block (video block) level.
  • the prediction block is generated by spatial (intra-picture) prediction and temporal (inter-picture) prediction.
  • the encoder duplicates the decoder processing loop so that the encoder and decoder generate the same prediction (eg, intra prediction and inter 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 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 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 of 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 .
  • the communication connection between the source device 12 and the destination device 14 may be via a link 13, and the destination device 14 may 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 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 type of picture capture device, for example to capture real-world pictures, and/or any type of picture or comment (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 picture elements.
  • 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. For example, for a picture in YUV format, it includes the luminance component indicated by Y (sometimes also indicated by L) and the two indicated by U and V. Chroma components.
  • 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 grading, 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 in 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 inter 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) via 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 post-picture 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 through 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.
  • a network of a category is, for example, a wired or wireless network or any combination thereof, or a private network and a public network of any category, 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 may be configured as a one-way communication interface or a two-way communication interface, and may 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). In some embodiments, the decoder 30 may be used to execute various embodiments described below to implement the application of the video decoding method described in this 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, for example, a user or a viewer.
  • 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 (LCD), an organic light emitting diode (OLED) display, a plasma display, a projector, a micro LED display, a 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 kind 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 can 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 (eg, video encoding or video decoding).
  • data can 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 a logic circuit 47), 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 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 include application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, or 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, etc., and the processor 43 may be implemented by general-purpose software, an operating system, or the like.
  • 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 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 memory 44) and a graphics processing unit.
  • 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.
  • 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 method described in the embodiment of the present application is mainly used in the inter prediction process. This process exists in both the encoder 20 and the decoder 30.
  • the encoder 20 and the decoder 30 in the embodiment of the present application may be, for example, H .263, H.264, HEVV, MPEG-2, MPEG-4, VP8, VP9 and other video standard protocols or next-generation video standard protocols (such as H.266, etc.) corresponding codec/decoder.
  • 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 of 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 division unit (not shown in FIG. 2) for dividing 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 picture 201) or three sampling arrays (for example, one brightness array and two chroma arrays in the case of color picture) 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) on 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 corresponding inverse transform by the inverse transform processing unit 212 on the encoder 20 side), and accordingly, the encoder can be The 20 side specifies a corresponding scaling factor for the positive transform through 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 a 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 the bitstream, for example.
  • Quantization is a lossy operation, where the larger the quantization step, the greater the loss.
  • the inverse quantization unit 210 is used to apply the inverse quantization of the quantization unit 208 on the quantized coefficients to obtain the inverse quantization coefficients 211, for example, based on or using the same quantization step size as the quantization unit 208, apply the quantization scheme applied by the quantization unit 208 Inverse quantization scheme.
  • the inverse quantized coefficient 211 may also be referred to as an inverse quantized residual coefficient 211, which corresponds to the transform coefficient 207, although the loss due to quantization is usually not the same as the transform coefficient.
  • the inverse transform processing unit 212 is used to apply the inverse transform of the transform applied by the transform processing unit 206, for example, an inverse discrete cosine transform (DCT) or an inverse discrete sine transform (DST), in the sample domain
  • the inverse transform block 213 is obtained.
  • the inverse transform block 213 may also be referred to as an inverse transform dequantized block 213 or an inverse transform residual block 213.
  • the reconstruction unit 214 (eg, summer 214) is used to add the inverse transform block 213 (ie, the reconstructed residual block 213) to the prediction block 265 to obtain the reconstructed block 215 in the sample domain, for example, The sample values of the reconstructed residual block 213 and the sample values of the prediction block 265 are added.
  • a buffer unit 216 (or simply "buffer" 216), such as a line buffer 216, is used to buffer or store the reconstructed block 215 and corresponding sample values for, for example, intra prediction.
  • the encoder may be used to use the unfiltered reconstructed blocks and/or corresponding sample values stored in the buffer unit 216 for any type of estimation and/or prediction, such as intra prediction.
  • an embodiment of the encoder 20 may be configured such that the buffer unit 216 is used not only to store the reconstructed block 215 for intra prediction 254, but also for the loop filter unit 220 (not shown in FIG. 2) Out), and/or, for example, causing the buffer unit 216 and the decoded picture buffer unit 230 to form a buffer.
  • Other embodiments may be used to use the filtered block 221 and/or blocks or samples from the decoded picture buffer 230 (neither shown in FIG. 2) as an input or basis for intra prediction 254.
  • the loop filter unit 220 (or simply "loop filter” 220) is used to filter the reconstructed block 215 to obtain the filtered block 221, so as to smoothly perform pixel conversion or improve video quality.
  • the loop filter unit 220 is intended to represent one or more loop filters, such as deblocking filters, sample-adaptive offset (SAO) filters, or other filters, such as bilateral filters, 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 encoding block after the loop filter unit 220 performs a filtering operation on the reconstructed encoding 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 encoding unit outputs after entropy encoding, for example, so that the decoder 30 can receive and apply the same loop filter parameters for decoding.
  • the decoded picture buffer (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 memory, 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 memory
  • DRAM dynamic random access memory
  • MRAM magnetoresistive RAM
  • RRAM resistive RAM
  • the DPB 230 and the buffer 216 may be provided by the same memory device or separate memory devices.
  • a decoded picture buffer (DPB) 230 is used to store the filtered block 221.
  • the decoded picture buffer 230 may be further used to store other previous filtered blocks of the same current picture or different pictures such as previous reconstructed pictures, such as the previously reconstructed and filtered block 221, and may provide the complete previous The reconstructed ie decoded pictures (and corresponding reference blocks and samples) and/or partially reconstructed current pictures (and corresponding reference blocks and samples), for example for inter prediction.
  • a decoded picture buffer (DPB) 230 is used to store the reconstructed block 215.
  • the prediction processing unit 260 also known as the block prediction processing unit 260, is used to receive or acquire the image block 203 (current image block 203 of the current picture 201) and reconstructed picture data, such as the same (current) picture from the buffer 216 Reference samples and/or reference picture data 231 of one or more previously decoded pictures from the decoded picture buffer 230, and used to process such data for prediction, that is, to provide an inter prediction block 245 or The prediction block 265 of the intra prediction block 255.
  • the mode selection unit 262 may be used to select a prediction mode (eg, intra or inter prediction mode) and/or the corresponding prediction block 245 or 255 used as the prediction block 265 to calculate the residual block 205 and reconstruct the reconstructed block 215.
  • a prediction mode eg, intra or inter prediction mode
  • the corresponding prediction block 245 or 255 used as the prediction block 265 to calculate the residual block 205 and reconstruct the reconstructed block 215.
  • An embodiment of the mode selection unit 262 may be used to select a prediction mode (for example, from those prediction modes supported by the prediction processing unit 260), which provides the best match or the minimum residual (the minimum residual means Better compression in transmission or storage), or provide minimum signaling overhead (minimum signaling overhead means better compression in transmission or storage), or consider or balance both at the same time.
  • the mode selection unit 262 may be used to determine a prediction mode based on rate distortion optimization (RDO), that is, to select a prediction mode that provides minimum bit rate distortion optimization, or to select a prediction mode in which the related bit 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, such as whether the entire reference picture is used or only used A part of the reference picture, for example a 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, for example, 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 this 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 prediction 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 the application 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 the picture sequence forming the video sequence, or form the picture 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 a 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 an 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) Coding (context adaptive) binary arithmetic coding (CABAC), syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval partition entropy (probability interval interpartitioning entropy, PIPE) coding 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) Coding
  • SBAC syntax-based context-adaptive binary arithmetic
  • the encoded bitstream may be transmitted to the video decoder 30 or archived for later transmission or retrieval by the video decoder 30.
  • the entropy encoding unit 270 may also be used to entropy encode other syntax elements of the current video slice being encoded.
  • video encoder 20 may be used to encode video streams.
  • the non-transform based encoder 20 may directly quantize the residual signal without the transform processing unit 206 for certain blocks or frames.
  • the encoder 20 may have a quantization unit 208 and an inverse quantization unit 210 combined into a single unit.
  • the encoder 20 may be used to implement the inter prediction method described in the embodiments below.
  • 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 coding, 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 reciprocal 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, wherein 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 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 of 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), sequence parameter set (SPS), and picture parameter set (picture parameter (set, PPS) or the syntax element in one or more of the stripe headers.
  • 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, so as 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 are added to the sample values of the prediction block 365.
  • the loop filter unit 320 (during the encoding loop or after the encoding loop) 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, self-adaptive 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 inter prediction method described in the embodiments 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 certain 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 in the case of 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 current image block derived from the motion vector of the adjacent affine coding block, or the motion vector of the sub-block derived from the current image block can be further processed, and this application does not do this limited.
  • the value range of the motion vector is constrained to be within a certain bit width. Assuming that the bit width of the allowed motion vector is bitDepth, the range of the motion vector is -2 bitDepth-1 ⁇ 2 bitDepth-1 -1. If bitDepth is 16, the value ranges from -32768 to 32767. If bitDepth is 18, the value ranges from -131072 to 131071.
  • the value of the motion vector (such as the motion vector MV of four 4 ⁇ 4 sub-blocks in an 8 ⁇ 8 image block) is constrained so that the integer parts of the four 4 ⁇ 4 sub-blocks MV
  • the maximum difference of is no more than N pixels, for example no more than one pixel.
  • 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 apparatus 400 is suitable for implementing the embodiments described herein.
  • the video decoding device 400 may be a video decoder (e.g., decoder 30 of FIG. 1A) or a video encoder (e.g., 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 receiving unit (Rx) 420, a processor for processing data, a logic unit or a central processing unit (CPU) 430, and a transmitter unit for transmitting data (Tx) 440 and exit port 450, and a memory 460 for storing data.
  • the video decoding device 400 may further include a photoelectric conversion component and an electro-optical (EO) component coupled to the inlet port 410, the receiver unit 420, the transmitter unit 440, and the outlet port 450 for the outlet or inlet of the optical signal or the electrical signal.
  • EO electro-optical
  • the processor 430 is implemented by hardware and software.
  • the processor 430 may be implemented as one or more CPU chips, cores (eg, multi-core processors), FPGA, ASIC, and DSP.
  • the processor 430 communicates with the inlet port 410, the receiver unit 420, the transmitter unit 440, the outlet port 450, and the memory 460.
  • the processor 430 includes a decoding module 470 (for example, an encoding module 470 or a decoding module 470).
  • the encoding/decoding module 470 implements the embodiments disclosed herein to implement the inter 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 to 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 hard disks, 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 program codes, and the processor can call the program codes stored in the memory to perform various video encoding or decoding methods described in this application. 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), and dedicated integrated Circuit (ASIC), ready-made programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.
  • the general-purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
  • the memory 530 may include a read only memory (ROM) device or a random access memory (RAM) device. Any other suitable type of storage device may also be used as the memory 530.
  • the memory 530 may include code and data 531 accessed by the processor 510 using the bus 550.
  • the memory 530 may further include an operating system 533 and an application program 535 including at least one program that allows the processor 510 to perform the video encoding or decoding method described in the present application (in particular, the inter prediction method described in the present application).
  • the application program 535 may include applications 1 to N, which further include a video encoding or decoding application (abbreviated as video coding 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.
  • Figure 6 describes the division of quadtree, binary tree and extended quadtree, among which:
  • QT is a tree structure, which means that a node can be divided into four child nodes.
  • Existing video coding standards use a quadtree-based CTU division method: CTU as the root node, each node corresponds to a square area; a node can no longer be divided (in this case, the corresponding area is a CU), or This node is divided into four next-level nodes, that is, the square area is divided into four square areas of the same size (the length and width of which are half of the length and width of the area before division), each area corresponds to a node . As shown in 6(a).
  • a binary tree is a tree structure, which means that a node can be divided into two child nodes.
  • a node on a binary tree structure may not be divided, or the node may be divided into two nodes at the next level.
  • Extended Quad-Tree (Extended-Quad-Tree, EQT) is an I-shaped partition structure, a node can be divided into four sub-nodes. There are two ways to divide it into three nodes: 1) Horizontal quartering, which divides the area corresponding to the node into upper, middle and lower areas, each area corresponds to a node, of which upper, middle left, middle right, The heights of the next three areas are 1/4, 1/2, 1/2, 1/4 of the node height, and the width of the middle left and right are 1/2, 1/2 of the height of the node, such as 6(d) As shown; or 2) Vertical quartering, the area corresponding to the node is divided into three areas: left, middle upper, middle lower, and right, each area corresponds to a node, wherein the width of the left, middle, and right areas They are 1/4, 1/2, 1/2, and 1/4 of the node height, respectively, and the upper, middle, and lower widths are 1/2 and 1/2 of the node height, as shown in 6(e). In
  • the H.265 video coding standard divides a frame of images into non-overlapping coding tree units (CTU).
  • the size of the CTU can be set to 64 ⁇ 64 (the size of the CTU can also be set to other values, such as CTU in the JVET reference software JEM The size increases to 128 ⁇ 128 or 256 ⁇ 256).
  • a 64 ⁇ 64 CTU contains a rectangular pixel lattice of 64 pixels in each column and each pixel contains a luminance component or/and a chrominance component.
  • the CTU is used as the root node of the quad-tree, and the CTU is recursively divided into several leaf nodes (leaf) according to the quad-tree division method node).
  • a node corresponds to an image area. If the node is not divided, the node is called a leaf node, and its corresponding image area forms a CU; if the node continues to be divided, the image area corresponding to the node is divided into four areas of the same size (which The length and width are each half of the divided area), each area corresponds to a node, you need to determine whether these nodes will be divided.
  • the quad-tree level (qtDepth) of the root node is 0, and the quad-tree level of the node is the quad-tree level of the parent node of the node plus 1.
  • the size and shape of the node in the following refers to the size and shape of the image area corresponding to the node.
  • the leaf node When a node is parsed as a leaf node, the leaf node is a CU, and further parses the coding information corresponding to the CU (including the CU prediction mode, transform coefficients and other information, such as the coding_unit() syntax structure in H.265), Then, according to these coding information, the CU is subjected to decoding processing such as prediction, inverse quantization, inverse transform, and loop filtering to generate a reconstructed image corresponding to this CU.
  • the quadtree structure allows the CTU to be divided into a group of CUs of appropriate size according to the local characteristics of the image, for example, smooth regions are divided into larger CUs, and texture-rich regions are divided into smaller CUs.
  • a CTU divided into a group of CUs corresponds to a coding tree (coding tree).
  • the coding tree that the CTU should use is usually determined by the rate-distortion optimization (RDO) technology of the encoder.
  • RDO rate-distortion optimization
  • the encoder tries a variety of CTU division methods, each of which corresponds to a rate-distortion cost (RD cost); the encoder compares the RD costs of various tried division methods and finds the division method with the smallest RD cost as the CTU
  • the optimal division method is used for the actual coding of the CTU.
  • the various CTU division methods tried by the encoder need to meet the division rules specified by the decoder, so that these can be correctly recognized by the decoder.
  • VTM Very Video Coding Test Model
  • BT binary tree
  • TT ternary tree
  • Binary tree division divides a node into two child nodes. There are two specific binary tree division methods:
  • the trigeminal tree division divides a node into three child nodes. There are two specific trigeminal tree division methods:
  • VTM uses the QT cascaded BT/TT division (Quad Tree plus Multi-Type Tree, QT-MTT) division method. More specifically, the CTU generates QT leaf nodes through QT division, and the nodes in QT can be further divided into four QT child nodes using quadtree division, or generate a QT leaf node without using quadtree division.
  • the QT leaf node serves as the root node of the MTT.
  • the nodes in the MTT can be divided into child nodes using one of the four division methods: horizontal dichotomy, vertical dichotomy, horizontal trisection, and vertical trisection, or they can no longer be divided into MTT leaf nodes.
  • the leaf node of MTT is a coding unit CU.
  • Figure 7 shows an example of using QT-MTT to divide a CTU into 16 CUs such as a to p.
  • Each end point in the right figure of FIG. 7 represents a node, a node connected with 4 lines represents a quadtree division, a node connected with 2 lines represents a binary tree division, and a node connected with 3 lines represents a trigeminal tree division.
  • the solid line represents the QT division, the dotted line represents the first layer division of Multi-Type Tree (MTT), and the dot-and-dash line represents the second layer division of MTT.
  • a to p are 16 MTT leaf nodes, and each MTT leaf node is 1 CU.
  • a CTU is divided into the CU as shown in the left diagram of FIG. 7 according to the division method of the right diagram of FIG. 7.
  • each CU has a QT level (Quad-tree depth, QT depth, also called QT depth) and an MTT level (Multi-Type Tree depth, MTT depth, also called MTT depth).
  • QT level represents the QT level of the QT leaf node to which the CU belongs
  • MTT level represents the MTT level of the MTT leaf node to which the CU belongs.
  • the QT level of the root node of the coding tree is 0, and the MTT level is 0.
  • the QT level of the divided child node is the QT level of the node plus 1, the MTT level remains unchanged; similarly, if a node on the coding tree uses MTT division (ie BT or TT One of the divisions), then the MTT level of the divided child node is the MTT level of the node plus 1, and the QT level remains unchanged.
  • MTT division ie BT or TT One of the divisions
  • the QT level of a, b, c, d, e, f, g, i, j is 1, and the MTT level is 2; the QT level of h is 1, and the MTT level is 1; n, o, p The QT level is 2, and the MTT level is 0; the QT level of l and m is 2, and the MTTT level is 1. If the CTU is divided into only one CU, the QT level of this CU is 0 and the MTT level is 0.
  • AVS3 added a binary tree (BT) division method and an extended quad-tree (EQT) division method on the basis of the quadtree division.
  • BT binary tree
  • EQT extended quad-tree
  • Binary tree division divides a node into two child nodes. There are two specific ways to divide a binary tree:
  • HBT Horizontal binary
  • VBT Vertical binary
  • Extended quadtree division divides a node into 4 sub-nodes. There are two specific ways to expand a quadtree:
  • HEQT Horizontal Extended
  • the area corresponding to the node is divided into upper, middle and lower areas, each area corresponds to a node, of which upper, middle left, middle right and lower three
  • the height of each area is 1/4, 1/2, 1/2, 1/4 of the node height
  • the width of the center left and center right is 1/2, 1/2 of the node height, as shown in 6(d) ;
  • VEQT Vertical Extended Quad-Tree
  • AVS3 uses the QT cascade BT/EQT division method, that is, the nodes on the first-level coding tree can only be divided into child nodes using QT.
  • the leaf nodes of the first-level coding tree are the root nodes of the second-level coding tree;
  • the nodes on the second-level coding tree can be divided into child nodes using one of the BT or EQT division methods;
  • the leaf nodes of the second-level coding tree are coding units. It should be noted that when a leaf node is divided into BT or EQT, its leaf nodes can only use BT or EQT, but not QT.
  • Video coding mainly includes intra prediction (Intra Prediction), inter prediction (Inter Prediction), transformation (Transform), and quantization (Quantization) ), Entropy encoding, in-loop filtering (mainly de-blocking filtering) and other links.
  • intra prediction or inter prediction is performed, and after the residual is obtained, transform and quantization are performed, and finally entropy coding is performed and the code stream is output.
  • the coding block is an M ⁇ N size array composed of pixels (M may be equal to N or may not be equal to N), and the pixel value of each pixel position is known.
  • Intra prediction refers to using the pixel values of pixels in the reconstructed area in the current image to predict the pixel values of pixels in the current coding block.
  • Inter prediction is to find a matching reference block for the current coding block in the current image in the reconstructed image, so as to obtain the motion information of the current coding block, and then calculate the pixel value of the pixel in the current coding block according to the motion information Predicted information or predicted value (in the following no longer distinguish between information and value).
  • the process of calculating motion information is called Motion Estimation (ME)
  • the process of calculating the predicted value of the pixel value of the pixel in the current coding block is called Motion Compensation (MC).
  • the motion information of the current coding block includes indication information of the prediction direction (usually forward prediction, backward prediction or bidirectional prediction), one or two motion vectors (Motion vector, MV) pointing to the reference block, And the indication information of the image where the reference block is located (usually referred to as reference frame index, Reference).
  • Forward prediction means that the current coding block selects one reference image from the set of forward reference images to obtain the reference block.
  • Backward prediction means that the current coding block selects a reference image from the set of backward reference images to obtain the reference block.
  • Bidirectional prediction refers to selecting a reference image from a set of forward and backward reference images to obtain a reference block.
  • each reference block needs a motion vector and a reference frame index to indicate, and then determine the pixels in the current block according to the pixel values of the pixels in the two reference blocks The predicted value of the pixel value.
  • the motion estimation process needs to try multiple reference blocks in the reference image for the current coding block. Which one or several reference blocks to use for prediction is determined using Rate-distortion Optimization (RDO) or other methods.
  • RDO Rate-distortion Optimization
  • the pixel value of the pixel in the current coding block is subtracted from the corresponding prediction information to obtain the residual information, and then the discrete cosine transform (Discrete Cosine Transformation, DCT) and other methods are used to resolve the residual information.
  • the difference information is transformed, and then quantized entropy coding is used to obtain a code stream.
  • a further filtering operation is required to obtain a reconstructed signal, which is used as a reference signal for subsequent encoding.
  • Decoding is equivalent to the reverse process of encoding. For example, first, entropy decoding, inverse quantization and inverse transformation are used to obtain residual information, and the code stream is decoded to determine whether the current coding block uses intra prediction or inter prediction.
  • intra prediction prediction information is constructed according to the intra prediction method used by using pixel values of pixels in the surrounding reconstructed area. If it is inter prediction, you need to parse out the motion information, and use the parsed motion information to determine the reference block in the reconstructed image, and use the pixel values of the pixels in the block as prediction information. This process is called motion compensation. (Motion compensation, MC).
  • the reconstruction information can be obtained by using the prediction information plus the residual information through a filtering operation.
  • the following embodiment is a process of determining the prediction mode of the current image block according to the code stream of the current image block.
  • FIG. 8 is a flowchart illustrating a prediction mode determination method according to an embodiment of the present application.
  • This process 800 may be performed by the video encoder 20 or the video decoder 30.
  • the process 800 is described as a series of steps or operations. It should be understood that the process 800 may be performed in various orders and/or simultaneously, and is not limited to the order of execution shown in FIG. 8. As shown in Figure 8, the method includes:
  • Step 801 Determine the division mode of the current image block.
  • the current image block may be divided into QT, BT, EQT, or other divisions, which are not limited in this application.
  • the current image block division method is usually carried in the code stream after encoding, and the current image block division method can be obtained by parsing the corresponding syntax element in the code stream.
  • the current image block may not need to be divided again, so the current image block is processed as a coding unit.
  • Step 802 Determine whether the first image sub-block that satisfies the preset condition will be obtained after the current image block is divided using the division method.
  • the preset condition in this application may include that the area of the first image sub-block is less than or equal to the set threshold. That is, this step can be judged based on the area of the current image block, that is, if the area of the current image block satisfies any of the following conditions, the first image sub-block will be obtained after the division is determined: when the division method is the binary tree BT division method, sizeC/ 2 is less than S, sizeC is the area of the current image block, and S is the preset area threshold; or, when the division method is the quadtree QT division method, sizeC/4 is less than S; or, when the division method is the extended quadtree EQT In the division method, sizeC/4 is smaller than S.
  • This application is to predict whether the first image sub-block whose area is less than the set threshold will be obtained after dividing the current image block, then according to the division method obtained in step 801, the area of each image sub-block after division can be known in advance.
  • BT division method the current image block is divided into 2 image sub-blocks, so it is judged whether sizeC/2 is less than S; if it is QT division method, the current image block is divided into 4 image sub-blocks, so it is judged whether sizeC/4 is less than S; If it is the EQT division method, the current image block is divided into 4 image sub-blocks, so it is judged whether sizeC/4 is smaller than S.
  • this application can also compare the area of multiple image sub-blocks obtained after the division with a set threshold, where the area of one or more image sub-blocks is less than the set threshold, it can be determined that after division In the first image sub-block, the image sub-block whose area is smaller than the set threshold is the first image sub-block. It should be noted that the present application may use various methods to determine whether the first image sub-block will be obtained after dividing the image sub-block, and the comparison is not specifically limited.
  • the width of the current image block is W and the height is H
  • Step 803 If it is determined that the first image sub-block will be obtained after division, the current image block is divided using a division method to obtain multiple image sub-blocks.
  • the multiple image sub-blocks obtained after the division necessarily include the above-mentioned first image sub-block.
  • Step 804 Determine that multiple image sub-blocks use the same prediction mode, and the prediction modes of the multiple image sub-blocks are both intra prediction modes or inter prediction modes.
  • the prediction modes of the divided multiple image sub-blocks are determined as the intra prediction mode or the inter prediction mode at the same time, so there is no need to analyze all the code streams, and the efficiency can be adjusted.
  • the process may include parsing the code stream of the current image block to determine the prediction mode of the second image sub-block.
  • the second image sub-block is the first image sub-block determined as the CU among the plurality of image sub-blocks according to the processing order; according to the second
  • the prediction mode of the image subblock determines the prediction mode of the image subblocks other than the second image subblock among the plurality of image subblocks. It should be noted that other methods can also be used for this process, which is not specifically limited in this application.
  • the above-mentioned second image sub-block is the first image sub-block determined as the CU among the multiple image sub-blocks obtained after the current image block is divided, and the code stream can be used to know how to divide the image sub-block. If the image sub-block is no longer divided, the image sub-block is determined to be a CU.
  • the encoding device or decoding device When facing multiple image sub-blocks, the encoding device or decoding device has a preset processing order, and the first image sub-block to be a CU in this order is the second image sub-block.
  • the prediction mode determination method can also determine the current image block division After the method, first use the division method to divide the current image block to obtain multiple image sub-blocks, and then determine whether the divided multiple image sub-blocks include the first image sub-block, the area of the first image sub-block is smaller than the set Set a threshold, and finally determine the prediction mode of multiple image sub-blocks.
  • the prediction modes in the embodiments of the present application are divided into intra prediction modes and inter prediction modes.
  • the inter prediction modes include skip mode (Skip Mode), direct mode (Direct Mode), or ordinary inter mode.
  • FIG. 9 is a flowchart illustrating a prediction mode determination method according to an embodiment of the present application.
  • the process 900 determines the prediction mode of the second image sub-block.
  • Process 900 may be performed by video encoder 20 or video decoder 30.
  • the process 900 is described as a series of steps or operations. It should be understood that the process 900 may be performed in various orders and/or simultaneously, and is not limited to the order of execution shown in FIG. 9.
  • the method includes:
  • Step 901 Analyze the code stream to obtain skip_flag.
  • skip_flag is the skip mode flag of the second image sub-block
  • the value of skipFlag is equal to the value of skip_flag. If skip_flag does not exist in the bitstream, the value of skipFlag is equal to 0.
  • Step 902 Determine whether the prediction mode of the second image sub-block is the skip mode according to skipFlag.
  • Step 903 Determine the prediction mode of the second image sub-block as the skip mode.
  • step 903 After the execution to step 903, the prediction mode of the second image sub-block has been determined. At this time, only skip_flag is parsed from the code stream, and it is not necessary to parse direct_flag and cu_pred_mode from the code stream, that is, it is not necessary to parse all code streams.
  • Step 904 Analyze the code stream to obtain direct_flag.
  • direct_flag is the direct mode identifier of the second image subblock
  • the value of directFlag is equal to the value of direct_flag. If direct_flag does not exist in the bitstream, the value of directFlag is equal to 0.
  • Step 905 Determine whether the prediction mode of the second image sub-block is a direct mode according to directFlag.
  • Step 906 Determine that the prediction mode of the second image sub-block is a direct mode.
  • step 906 After execution to step 906, the prediction mode of the second image sub-block has been determined. At this time, only skip_flag and direct_flag are parsed from the code stream, and cu_pred_mode does not need to be parsed from the code stream, that is, it is not necessary to parse all code streams.
  • Step 907 Analyze the code stream to obtain cu_pred_mode.
  • cu_pred_mode is the prediction mode identifier of the second image subblock
  • the value of CuPredMode is equal to cu_pred_mode. If cu_pred_mode does not exist in the bit stream and the current frame is an I frame, CuPredMode is equal to 1.
  • Step 908 Determine whether the prediction mode of the second image sub-block is an intra prediction mode according to CuPredMode.
  • Step 909 Determine the prediction mode of the second image sub-block as the intra prediction mode.
  • Step 910 Determine that the prediction mode of the second image sub-block is a normal inter mode.
  • Step 910 is executed to determine the prediction mode of the second image sub-block. At this time, all flags skip_flag, direct_flag, and cu_pred_mode are parsed from the code stream.
  • FIG. 10 is a flowchart illustrating a prediction mode determination method according to an embodiment of the present application.
  • the process 1000 determines prediction modes of image sub-blocks other than the second image sub-block.
  • Process 1000 may be performed by video encoder 20 or video decoder 30.
  • the process 1000 is described as a series of steps or operations. It should be understood that the process 1000 may be performed in various orders and/or simultaneously, and is not limited to the order of execution shown in FIG. 10.
  • the method includes:
  • Step 1001 When the prediction mode of the second image sub-block is the inter prediction mode, parse the code stream to obtain skip_flag.
  • skip_flag is the skip mode flag of other image sub-blocks
  • the value of skipFlag is equal to the value of skip_flag. If skip_flag does not exist in the bitstream, the value of skipFlag is equal to 0.
  • Step 1002 Determine whether the prediction mode of other image sub-blocks is the skip mode according to skipFlag.
  • Step 1003 Determine the prediction mode of other image sub-blocks as skip mode.
  • step 1003 the prediction modes of other image sub-blocks have been determined. At this time, only skip_flag is parsed from the code stream, and direct_flag and cu_pred_mode do not need to be parsed from the code stream, that is, all code streams need not be parsed.
  • Step 1004 Analyze the code stream to obtain direct_flag.
  • direct_flag is the direct mode identifier of other image sub-blocks
  • the value of directFlag is equal to the value of direct_flag. If direct_flag does not exist in the bitstream, the value of directFlag is equal to 0.
  • Step 1005 Determine whether the prediction mode of other image sub-blocks is the direct mode according to directFlag.
  • Step 1006 Determine the prediction mode of other image sub-blocks as a direct mode.
  • step 1006 the prediction modes of other image sub-blocks have been determined. At this time, only skip_flag and direct_flag are parsed from the code stream, and cu_pred_mode does not need to be parsed from the code stream, that is, all code streams need not be parsed.
  • Step 1007 Determine the prediction mode of the other image sub-blocks as a normal inter mode.
  • the other image sub-blocks Due to the inter prediction mode used by the second image sub-block, in order to maintain consistency, the other image sub-blocks only select the prediction mode in the inter prediction mode, and after step 1007, only the normal inter mode is left, then determine other images
  • the prediction mode of the sub-block is a normal inter mode, and there is no need to analyze cu_pred_mode from the code stream.
  • Step 1008 When the prediction mode of the second image sub-block is an intra prediction mode, analyze the code stream to determine that the prediction mode of other image sub-blocks is one of the intra prediction modes.
  • the intra prediction mode includes the intra luma prediction mode and the intra chroma prediction mode.
  • intra_chroma_prediction_mode is used to determine the intra prediction mode of two chroma blocks whose PredBlockOrder is NumOfIntraPredBlock and NumOfIntraPredBlock+1 in the 4:2:0 format coding block.
  • step 1008 can determine the prediction mode of other image sub-blocks without parsing any identifier from the code stream.
  • the prediction mode of the image subblock with a smaller area is determined based on the prediction mode of one of the image subblocks divided by the current image block, Therefore, it is not necessary to parse all code streams, and the same prediction mode as other image sub-blocks is used for image sub-blocks with a small area, which is convenient for hardware pipeline processing.
  • FIG. 11 is a schematic block diagram of a prediction mode determining apparatus 1100 in an embodiment of the present application.
  • the prediction mode determining apparatus 1100 may include: a determining module 1101, a determining module 1102, a dividing module 1103, and a predicting module 1104, wherein the determining module 1101 is used to determine the current image block division method; the determining module 1102 is used to determine the use of Whether the first image sub-block meeting the preset condition will be obtained after dividing the current image block in the dividing manner; the dividing module 1103 is used to determine whether the first image sub-block will be obtained after dividing Dividing the current image block into multiple image sub-blocks, the multiple image sub-blocks including the first image sub-block; the prediction module 1104 is used to determine that the multiple image sub-blocks use the same Prediction mode.
  • the prediction modes of the multiple image sub-blocks are both intra prediction modes or inter prediction modes.
  • the preset condition includes that the area of the first image sub-block is less than or equal to a set threshold.
  • the prediction module 1104 is specifically configured to parse the code stream of the current image block to determine the prediction mode of the second image sub-block, and the second image sub-block is the multiple images
  • the first of the sub-blocks is determined to be the image sub-block of the coding unit CU, and the prediction mode of the second image sub-block is the intra prediction mode or the inter prediction mode; according to the second image sub-block
  • the prediction mode determines the prediction mode of the image subblocks other than the second image subblock among the plurality of image subblocks.
  • the prediction mode of the other image subblocks is the same as the prediction mode of the second image subblocks It is the intra prediction mode or the inter prediction mode.
  • the inter prediction mode includes a skip mode, a direct mode, or a normal inter mode.
  • the prediction module 1104 is specifically configured to parse the code stream to obtain the other image subblocks when the prediction mode of the second image subblock is the inter prediction mode Skip mode identifier, and determine whether the prediction mode of the other image sub-blocks is the skip mode according to the skip mode identifier; if the skip mode identifier indicates that the skip mode is used, determine The prediction mode of the other image sub-blocks is the skip mode.
  • the prediction module 1104 is further configured to parse the code stream to obtain the direct mode of the other image sub-blocks if the skip mode indicator indicates that the skip mode is not used. Flag, and determine whether the prediction mode of the other image sub-blocks is the direct mode according to the direct mode flag; if the direct mode flag indicates that the direct mode is used, determine the prediction mode of the other image sub-blocks Is the direct mode; if the direct mode identifier indicates that the direct mode is not used, determining that the prediction mode of the other image sub-blocks is the normal inter mode.
  • the prediction module 1104 is specifically configured to parse the code stream to determine the other image subblocks when the prediction mode of the second image subblock is the intra prediction mode
  • the prediction mode of is one of the intra prediction modes.
  • the judgment module 1102 is specifically configured to obtain the first image sub-block after determining the division if the area of the current image block satisfies the following conditions: when the division method is In the binary tree BT division method, sizeC/2 is less than S, sizeC is the area of the current image block, and S is a preset area threshold; or, when the division method is the quadtree QT division method, sizeC/4 is less than S Or, when the division method is an extended quadtree EQT division method, sizeC/4 is smaller than S.
  • the dividing module 1103 is further configured to divide the current image block by using the dividing method to obtain multiple if it is determined that the first image sub-block will not be obtained after dividing Image sub-blocks, and determine the division manner of the plurality of image sub-blocks respectively, and use the corresponding division manner to divide the image sub-blocks respectively.
  • the prediction module 1104 is specifically configured to parse the code stream to obtain a skip mode identifier of the second image sub-block, and determine the second mode according to the skip mode identifier Whether the prediction mode of the image sub-block is the skip mode; if the skip mode flag indicates that the skip mode is used, it is determined that the prediction mode of the second image sub-block is the skip mode.
  • the prediction module 1104 is further configured to: if the skip mode indicator indicates that the skip mode is not used, parse the code stream to obtain the second image sub-block directly A mode identifier, and determine whether the prediction mode of the second image sub-block is the direct mode according to the direct mode identifier; if the direct mode identifier indicates that the direct mode is used, determine the second image sub-block Is the direct mode.
  • the prediction module 1104 is further configured to parse the prediction mode identifier of the second image sub-block of the code stream if the direct mode identifier indicates that the direct mode is not used, And determine whether the prediction mode of the second image sub-block is the intra prediction mode according to the prediction mode identifier; if the prediction mode identifier indicates the use of the intra prediction mode, determine the second image sub The prediction mode of the block is the intra prediction mode; if the prediction mode indicator indicates that a normal inter mode is used, it is determined that the prediction mode of the second image sub-block is the normal inter mode.
  • each module in the inter-frame prediction apparatus of the embodiment of the present application is a functional body that implements various execution steps included in the inter-frame prediction method of the present application, that is, it is capable of implementing a complete implementation of the inter-frame prediction method of the present application.
  • the various steps of the steps and the functional body of the expansion and deformation of these steps please refer to the introduction of the inter prediction method in this article for details. For the sake of brevity, this article will not repeat them.
  • Computer-readable media may include computer-readable storage media, which corresponds to tangible media, such as data storage media, or communication media including any medium that facilitates transfer of a computer program from one place to another (eg, according to a communication protocol).
  • computer-readable media may generally correspond to (1) non-transitory tangible computer-readable storage media, or (2) communication media, such as signals or carrier waves.
  • Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and/or data structures for implementation of the techniques described in this application.
  • the computer program product may include a computer-readable medium.
  • Such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM, or other optical disk storage devices, magnetic disk storage devices, or other magnetic storage devices, flash memory, or may be used to store instructions or data structures
  • the desired program code in the form of and any other medium that can be accessed by the computer. And, any connection is properly called a computer-readable medium.
  • coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technology such as infrared, radio, and microwave is used to transmit instructions from a website, server, or other remote source
  • coaxial cable Wire, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of media.
  • the computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other temporary media, but are actually directed to non-transitory tangible storage media.
  • magnetic disks and optical discs include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), and Blu-ray discs, where magnetic discs typically reproduce data magnetically, while optical discs reproduce optically using lasers data. Combinations of the above should also be included in the scope of computer-readable media.
  • DSPs digital signal processors
  • ASICs application specific integrated circuits
  • FPGAs field programmable logic arrays
  • processors may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein.
  • the functions described in the various illustrative logical blocks, modules, and steps described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or in combination Into the combined codec.
  • the techniques can be fully implemented in one or more circuits or logic elements.
  • the technology of the present application may be implemented in a variety of devices or equipment, including wireless handsets, integrated circuits (ICs), or a set of ICs (eg, chipsets).
  • ICs integrated circuits
  • a set of ICs eg, chipsets
  • Various components, modules or units are described in this application to emphasize the functional aspects of the device for performing the disclosed technology, but do not necessarily need to be implemented by different hardware units.
  • various units may be combined in a codec hardware unit in combination with suitable software and/or firmware, or by interoperating hardware units (including one or more processors as described above) provide.

Abstract

本申请公开了预测模式确定方法、装置及编码设备和解码设备，该方法包括：确定当前图像块的划分方式；判断使用所述划分方式对所述当前图像块进行划分后是否会得到满足预设条件的第一图像子块；若判断划分后会得到所述第一图像子块，则使用所述划分方式对所述当前图像块进行划分得到多个图像子块，所述多个图像子块包括所述第一图像子块；确定所述多个图像子块采用相同的预测模式，所述多个图像子块的预测模式同为帧内预测模式或帧间预测模式。实施本申请无需解析所有码流，便于硬件的流水处理，提高效率。

Description

预测模式确定方法、装置及编码设备和解码设备
本申请要求于2018年12月27日提交中国专利局、申请号为201811613699.3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。
本申请要求于2019年3月22日提交中国专利局、申请号为201910222962.4、申请名称为“预测模式确定方法、装置及编码设备和解码设备”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
本申请涉及视频编码领域，尤其涉及一种预测模式确定方法、装置及编码设备和解码设备。
背景技术
视频编码(视频编码和解码)广泛用于数字视频应用，例如广播数字电视、互联网和移动网络上的视频传播、视频聊天和视频会议等实时会话应用、DVD和蓝光光盘、视频内容采集和编辑系统以及可携式摄像机的安全应用。
随着1990年H.261标准中基于块的混合型视频编码方式的发展，新的视频编码技术和工具得到发展并为新的视频编码标准形成基础。其它视频编码标准包括MPEG-1视频、MPEG-2视频、ITU-T H.262/MPEG-2、ITU-T H.263、ITU-T H.264/MPEG-4第10部分高级视频编码(Advanced Video Coding，AVC)、ITU-T H.265/高效视频编码(High Efficiency Video Coding，HEVC)…以及此类标准的扩展，例如可扩展性和/或3D(three-dimensional)扩展。随着视频创建和使用变得越来越广泛，视频流量成为通信网络和数据存储的最大负担。因此大多数视频编码标准的目标之一是相较之前的标准，在不牺牲图片质量的前提下减少比特率。即使最新的HEVC可以在不牺牲图片质量的前提下比AVC大约多压缩视频一倍，仍然亟需新技术相对HEVC进一步压缩视频。
在编码一帧图像时，首先将图像划分为等大小的图像块，称为最大编码单元(Largest Coding Unit，LCU)，再对一个LCU进行递归的划分操作，可以得到一个或多个编码单元(Coding Unit，CU)。LCU的形状有两种，128×128或64×64。现有编码标准在四叉树(Quad-Tree，QT)划分的基础上，增加了二叉树(Binary Tree，BT)划分方式(包括水平二叉树(Horizontal Binary Tree，HBT)和竖直二叉树(Vertical Binary Tree，VBT))和扩展四叉树(Extended Quad Tree，EQT)划分方式(包括水平扩展四叉树(Horizontal Extended Quad Tree，HEQT)和竖直扩展四叉树(Vertical Extended Quad Tree，VEQT))。基于此，一个图像块会被划分成多个不同的CU，各CU可能会使用不同的预测模式。
但是，对于面积小于64的图像块，其处理效率会很低。
发明内容
本申请实施例提供一种预测模式确定方法、装置及编码设备和解码设备，在根据当前图像块的码流确定当前图像块的预测模式的过程中，无需解析所有码流，便于硬件的流水处理。
第一方面，本申请提供一种预测模式确定方法，包括：确定当前图像块的划分方式；判断使用所述划分方式对所述当前图像块进行划分后是否会得到满足预设条件的第一图像子块；若判断划分后会得到所述第一图像子块，则使用所述划分方式对所述当前图像块进行划分得到多个图像子块，所述多个图像子块包括所述第一图像子块；确定所述多个图像子块采用相同的预测模式，所述多个图像子块的预测模式同为帧内预测模式或帧间预测模式。
在一种可能的实现方式中，所述的预设条件包括所述第一图像子块的面积小于或者等于设定的阈值。
在一种可能的实现方式中，所述确定所述多个图像子块采用相同的预测模式，包括：解析所述当前图像块的码流确定第二图像子块的预测模式，所述第二图像子块为所述多个图像子块中按照处理顺序第一个确定为编码单元CU的图像子块，所述第二图像子块的预测模式为所述帧内预测模式或所述帧间预测模式；根据所述第二图像子块的预测模式确定所述多个图像子块中除所述第二图像子块外的其他图像子块的预测模式，所述其他图像子块的预测模式与所述第二图像子块的预测模式同为所述帧内预测模式或所述帧间预测模式。
在一种可能的实现方式中，所述帧间预测模式包括跳过模式、直接模式或普通帧间模式。
在一种可能的实现方式中，所述根据所述第二图像子块的预测模式确定所述多个图像子块中除所述第二图像子块外的其他图像子块的预测模式，包括：当所述第二图像子块的预测模式为所述帧间预测模式时，解析所述码流获取所述其他图像子块的跳过模式标识，并根据所述跳过模式标识判断所述其他图像子块的预测模式是否为所述跳过模式；若所述跳过模式标识指示使用所述跳过模式，则确定所述其他图像子块的预测模式为所述跳过模式。
在一种可能的实现方式中，所述根据所述第二图像子块的预测模式确定所述多个图像子块中除所述第二图像子块外的其他图像子块的预测模式，还包括：若所述跳过模式标识指示不使用所述跳过模式，则解析所述码流获取所述其他图像子块的直接模式标识，并根据所述直接模式标识判断所述其他图像子块的预测模式是否为所述直接模式；若所述直接模式标识指示使用所述直接模式，则确定所述其他图像子块的预测模式为所述直接模式；若所述直接模式标识指示不使用所述直接模式，则确定所述其他图像子块的预测模式为所述普通帧间模式。
在一种可能的实现方式中，所述根据所述第二图像子块的预测模式确定所述多个图像子块中除所述第二图像子块外的其他图像子块的预测模式，包括：当所述第二图像子块的预测模式为所述帧内预测模式时，解析所述码流确定所述其他图像子块的预测模式为所述帧内预测模式的其中一种。
在一种可能的实现方式中，所述判断使用所述划分方式对所述当前图像块进行划分后是否会得到满足预设条件的第一图像子块，包括：若所述当前图像块的面积满足以下条件，则确定划分后会得到所述第一图像子块：当所述划分方式为二叉树BT划分方式时，sizeC/2小于S，sizeC为所述当前图像块的面积，S为预设面积阈值；或者，当所述划分方式为四叉树QT划分方式时，sizeC/4小于S；或者，当所述划分方式为扩展四叉树EQT划分方 式时，sizeC/4小于S。
在一种可能的实现方式中，所述判断使用所述划分方式对所述当前图像块进行划分后是否会得到满足预设条件的第一图像子块之后，还包括：若判断划分后不会得到所述第一图像子块，则使用所述划分方式对所述当前图像块进行划分得到多个图像子块，并分别确定所述多个图像子块的划分方式，对各所述图像子块使用对应的划分方式分别进行划分。
在一种可能的实现方式中，所述解析所述当前图像块的码流确定第二图像子块的预测模式，包括：解析所述码流获取所述第二图像子块的跳过模式标识，并根据所述跳过模式标识判断所述第二图像子块的预测模式是否为所述跳过模式；若所述跳过模式标识指示使用所述跳过模式，则确定所述第二图像子块的预测模式为所述跳过模式。
在一种可能的实现方式中，所述解析所述当前图像块的码流确定第二图像子块的预测模式，还包括：若所述跳过模式标识指示不使用所述跳过模式，则解析所述码流获取所述第二图像子块的直接模式标识，并根据所述直接模式标识判断所述第二图像子块的预测模式是否为所述直接模式；若所述直接模式标识指示使用所述直接模式，则确定所述第二图像子块的预测模式为所述直接模式。
在一种可能的实现方式中，所述解析所述当前图像块的码流确定第二图像子块的预测模式，还包括：若所述直接模式标识指示不使用所述直接模式，则解析所述码流所述第二图像子块的预测模式标识，并根据所述预测模式标识判断所述第二图像子块的预测模式是否为所述帧内预测模式；若所述预测模式标识指示使用所述帧内预测模式，则确定所述第二图像子块的预测模式为所述帧内预测模式；若所述预测模式标识指示使用普通帧间模式，则确定所述第二图像子块的预测模式为所述普通帧间模式。
本申请实施例在根据当前图像块的码流确定当前图像块的预测模式的过程中，基于当前图像块划分出的其中一个图像子块的预测模式确定其他图像子块，尤其是面积较小的图像子块的预测模式，从而无需解析所有码流，而且对于面积小的图像子块使用和其他图像子块相同的预测模式，便于硬件的流水处理。
第二方面，本申请提供一种预测模式确定装置，包括：确定模块，用于确定当前图像块的划分方式；判断模块，用于判断使用所述划分方式对所述当前图像块进行划分后是否会得到满足预设条件的第一图像子块；划分模块，用于若判断划分后会得到所述第一图像子块，则使用所述划分方式对所述当前图像块进行划分得到多个图像子块，所述多个图像子块包括所述第一图像子块；预测模块，用于确定所述多个图像子块采用相同的预测模式，所述多个图像子块的预测模式同为帧内预测模式或帧间预测模式。
在一种可能的实现方式中，所述的预设条件包括所述第一图像子块的面积小于或者等于设定的阈值。
在一种可能的实现方式中，所述预测模块，具体用于解析所述当前图像块的码流确定第二图像子块的预测模式，所述第二图像子块为所述多个图像子块中按照处理顺序第一个确定为编码单元CU的图像子块，所述第二图像子块的预测模式为所述帧内预测模式或所述帧间预测模式；根据所述第二图像子块的预测模式确定所述多个图像子块中除所述第二图像子块外的其他图像子块的预测模式，所述其他图像子块的预测模式与所述第二图像子块的预测模式同为所述帧内预测模式或所述帧间预测模式。
在一种可能的实现方式中，所述帧间预测模式包括跳过模式、直接模式或普通帧间模 式。
在一种可能的实现方式中，所述预测模块，具体用于当所述第二图像子块的预测模式为所述帧间预测模式时，解析所述码流获取所述其他图像子块的跳过模式标识，并根据所述跳过模式标识判断所述其他图像子块的预测模式是否为所述跳过模式；若所述跳过模式标识指示使用所述跳过模式，则确定所述其他图像子块的预测模式为所述跳过模式。
在一种可能的实现方式中，所述预测模块，还用于若所述跳过模式标识指示不使用所述跳过模式，则解析所述码流获取所述其他图像子块的直接模式标识，并根据所述直接模式标识判断所述其他图像子块的预测模式是否为所述直接模式；若所述直接模式标识指示使用所述直接模式，则确定所述其他图像子块的预测模式为所述直接模式；若所述直接模式标识指示不使用所述直接模式，则确定所述其他图像子块的预测模式为所述普通帧间模式。
在一种可能的实现方式中，所述预测模块，具体用于当所述第二图像子块的预测模式为所述帧内预测模式时，解析所述码流确定所述其他图像子块的预测模式为所述帧内预测模式的其中一种。
在一种可能的实现方式中，所述判断模块，具体用于若所述当前图像块的面积满足以下条件，则确定划分后会得到所述第一图像子块：当所述划分方式为二叉树BT划分方式时，sizeC/2小于S，sizeC为所述当前图像块的面积，S为预设面积阈值；或者，当所述划分方式为四叉树QT划分方式时，sizeC/4小于S；或者，当所述划分方式为扩展四叉树EQT划分方式时，sizeC/4小于S。
在一种可能的实现方式中，所述划分模块，还用于若判断划分后不会得到所述第一图像子块，则使用所述划分方式对所述当前图像块进行划分得到多个图像子块，并分别确定所述多个图像子块的划分方式，对各所述图像子块使用对应的划分方式分别进行划分。
在一种可能的实现方式中，所述预测模块，具体用于解析所述码流获取所述第二图像子块的跳过模式标识，并根据所述跳过模式标识判断所述第二图像子块的预测模式是否为所述跳过模式；若所述跳过模式标识指示使用所述跳过模式，则确定所述第二图像子块的预测模式为所述跳过模式。
在一种可能的实现方式中，所述预测模块，还用于若所述跳过模式标识指示不使用所述跳过模式，则解析所述码流获取所述第二图像子块的直接模式标识，并根据所述直接模式标识判断所述第二图像子块的预测模式是否为所述直接模式；若所述直接模式标识指示使用所述直接模式，则确定所述第二图像子块的预测模式为所述直接模式。
在一种可能的实现方式中，所述预测模块，还用于若所述直接模式标识指示不使用所述直接模式，则解析所述码流所述第二图像子块的预测模式标识，并根据所述预测模式标识判断所述第二图像子块的预测模式是否为所述帧内预测模式；若所述预测模式标识指示使用所述帧内预测模式，则确定所述第二图像子块的预测模式为所述帧内预测模式；若所述预测模式标识指示使用普通帧间模式，则确定所述第二图像子块的预测模式为所述普通帧间模式。
第三方面，本申请提供一种视频编码设备，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上述第一方面中任一项所描述的方法。
第四方面，本申请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，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上述第一方面中任一项所描述的方法。
第五方面，本申请实施例提供一种计算机程序产品，当所述计算机程序产品在计算机上运行时，使得所述计算机执行第一方面的任意一种方法的部分或全部步骤。
应当理解的是，本申请的第二至五方面与本申请的第一方面的技术方案一致，各方面及对应的可行实施方式所取得的有益效果相似，不再赘述。
附图说明
为了更清楚地说明本申请实施例或背景技术中的技术方案，下面将对本申请实施例或背景技术中所需要使用的附图进行说明。
图1A是用于实现本申请实施例的视频编码及解码系统10实例的框图；
图1B是用于实现本申请实施例的视频译码系统40实例的框图；
图2是用于实现本申请实施例的编码器20实例结构的框图；
图3是用于实现本申请实施例的解码器30实例结构的框图；
图4是用于实现本申请实施例的视频译码设备400实例的框图；
图5是用于实现本申请实施例的另一种编码装置或解码装置实例的框图；
图6是用于实现本申请实施例的二叉树，四叉树以及扩展四叉树的划分方式示意图；
图7是用于实现本申请实施例的QT-MTT划分示意图；
图8是示出根据本申请一种实施例的预测模式确定方法的流程图；
图9是示出根据本申请一种实施例的预测模式确定方法的流程图；
图10是示出根据本申请一种实施例的预测模式确定方法的流程图；
图11为本申请实施例中的预测模式确定装置1100的一种示意性框图。
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、高性能视频编码(High Efficiency Video Coding，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)，或者可能应用于在数字音视频编解码(Audio Video coding Standard Workgroup of China，AVS)技术标准，如AVS3中。本发明的实施方式部分使用的术语仅用于对本发明的具体实施例进行解释，而非旨在限定本发明。下面先对本申请实施例可能涉及的一些概念进行简单介绍。
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)。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。比如视频编码标准把一帧图像分割成互不重叠的编码树单元(Coding Tree Unit，CTU)，再把一个CTU划分为若干个子节点，这些子节点可以按照四叉树(Quad Tree，QT)进行划分为更小的子节点，而更小的子节点还可以继续划分，从而形成一种四叉树结构。如果节点不再划分，则叫做CU。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TU。在视频压缩技术最新的发展中，使用四叉树和二叉树(Quad-tree and binary tree，QTBT)分割帧来分割编码块。在QTBT块结构中，CU可以为正方形或矩形形状。
本文中，为了便于描述和理解，可将当前编码图像中待编码的图像块称为当前块，例如在编码中，指当前正在编码的块；在解码中，指当前正在解码的块。将参考图像中用于对当前块进行预测的已解码的图像块称为参考块，即参考块是为当前块提供参考信号的块，其中，参考信号表示图像块内的像素值。可将参考图像中为当前块提供预测信号的块为预测块，其中，预测信号表示预测块内的像素值或者采样值或者采样信号。例如，在遍 历多个参考块以后，找到了最佳参考块，此最佳参考块将为当前块提供预测，此块称为预测块。
无损视频编码情况下，可以重构原始视频图片，即经重构视频图片具有与原始视频图片相同的质量(假设存储或传输期间没有传输损耗或其它数据丢失)。在有损视频编码情况下，通过例如量化执行进一步压缩，来减少表示视频图片所需的数据量，而解码器侧无法完全重构视频图片，即经重构视频图片的质量相比原始视频图片的质量较低或较差。
H.261的几个视频编码标准属于“有损混合型视频编解码”(即，将样本域中的空间和时间预测与变换域中用于应用量化的2D变换编码结合)。视频序列的每个图片通常分割成不重叠的块集合，通常在块层级上进行编码。换句话说，编码器侧通常在块(视频块)层级处理亦即编码视频，例如，通过空间(图片内)预测和时间(图片间)预测来产生预测块，从当前块(当前处理或待处理的块)减去预测块以获取残差块，在变换域变换残差块并量化残差块，以减少待传输(压缩)的数据量，而解码器侧将相对于编码器的逆处理部分应用于经编码或经压缩块，以重构用于表示的当前块。另外，编码器复制解码器处理循环，使得编码器和解码器生成相同的预测(例如帧内预测和帧间预测)和/或重构，用于处理亦即编码后续块。
下面描述本申请实施例所应用的系统架构。参见图1A，图1A示例性地给出了本申请实施例所应用的视频编码及解码系统10的示意性框图。如图1A所示，视频编码及解码系统10可包括源设备12和目的地设备14，源设备12产生经编码视频数据，因此，源设备12可被称为视频编码装置。目的地设备14可对由源设备12所产生的经编码的视频数据进行解码，因此，目的地设备14可被称为视频解码装置。源设备12、目的地设备14或两个的各种实施方案可包含一或多个处理器以及耦合到所述一或多个处理器的存储器。所述存储器可包含但不限于RAM、ROM、EEPROM、快闪存储器或可用于以可由计算机存取的指令或数据结构的形式存储所要的程序代码的任何其它媒体，如本文所描述。源设备12和目的地设备14可以包括各种装置，包含桌上型计算机、移动计算装置、笔记型(例如，膝上型)计算机、平板计算机、机顶盒、例如所谓的“智能”电话等电话手持机、电视机、相机、显示装置、数字媒体播放器、视频游戏控制台、车载计算机、无线通信设备或其类似者。
虽然图1A将源设备12和目的地设备14绘示为单独的设备，但设备实施例也可以同时包括源设备12和目的地设备14或同时包括两者的功能性，即源设备12或对应的功能性以及目的地设备14或对应的功能性。在此类实施例中，可以使用相同硬件和/或软件，或使用单独的硬件和/或软件，或其任何组合来实施源设备12或对应的功能性以及目的地设备14或对应的功能性。
源设备12和目的地设备14之间可通过链路13进行通信连接，目的地设备14可经由链路13从源设备12接收经编码视频数据。链路13可包括能够将经编码视频数据从源设备12移动到目的地设备14的一或多个媒体或装置。在一个实例中，链路13可包括使得源设备12能够实时将经编码视频数据直接发射到目的地设备14的一或多个通信媒体。在此实例中，源设备12可根据通信标准(例如无线通信协议)来调制经编码视频数据，且可将经调制的视频数据发射到目的地设备14。所述一或多个通信媒体可包含无线和/或有 线通信媒体，例如射频(RF)频谱或一或多个物理传输线。所述一或多个通信媒体可形成基于分组的网络的一部分，基于分组的网络例如为局域网、广域网或全球网络(例如，因特网)。所述一或多个通信媒体可包含路由器、交换器、基站或促进从源设备12到目的地设备14的通信的其它设备。
源设备12包括编码器20，另外可选地，源设备12还可以包括图片源16、图片预处理器18、以及通信接口22。具体实现形态中，所述编码器20、图片源16、图片预处理器18、以及通信接口22可能是源设备12中的硬件部件，也可能是源设备12中的软件程序。分别描述如下：
图片源16，可以包括或可以为任何类别的图片捕获设备，用于例如捕获现实世界图片，和/或任何类别的图片或评论(对于屏幕内容编码，屏幕上的一些文字也认为是待编码的图片或图像的一部分)生成设备，例如，用于生成计算机动画图片的计算机图形处理器，或用于获取和/或提供现实世界图片、计算机动画图片(例如，屏幕内容、虚拟现实(virtual reality，VR)图片)的任何类别设备，和/或其任何组合(例如，实景(augmented reality，AR)图片)。图片源16可以为用于捕获图片的相机或者用于存储图片的存储器，图片源16还可以包括存储先前捕获或产生的图片和/或获取或接收图片的任何类别的(内部或外部)接口。当图片源16为相机时，图片源16可例如为本地的或集成在源设备中的集成相机；当图片源16为存储器时，图片源16可为本地的或例如集成在源设备中的集成存储器。当所述图片源16包括接口时，接口可例如为从外部视频源接收图片的外部接口，外部视频源例如为外部图片捕获设备，比如相机、外部存储器或外部图片生成设备，外部图片生成设备例如为外部计算机图形处理器、计算机或服务器。接口可以为根据任何专有或标准化接口协议的任何类别的接口，例如有线或无线接口、光接口。
其中，图片可以视为像素点(picture element)的二维阵列或矩阵。阵列中的像素点也可以称为采样点。阵列或图片在水平和垂直方向(或轴线)上的采样点数目定义图片的尺寸和/或分辨率。为了表示颜色，通常采用三个颜色分量，即图片可以表示为或包含三个采样阵列。例如在RBG格式或颜色空间中，图片包括对应的红色、绿色及蓝色采样阵列。但是，在视频编码中，每个像素通常以亮度/色度格式或颜色空间表示，例如对于YUV格式的图片，包括Y指示的亮度分量(有时也可以用L指示)以及U和V指示的两个色度分量。亮度(luma)分量Y表示亮度或灰度水平强度(例如，在灰度等级图片中两者相同)，而两个色度(chroma)分量U和V表示色度或颜色信息分量。相应地，YUV格式的图片包括亮度采样值(Y)的亮度采样阵列，和色度值(U和V)的两个色度采样阵列。RGB格式的图片可以转换或变换为YUV格式，反之亦然，该过程也称为色彩变换或转换。如果图片是黑白的，该图片可以只包括亮度采样阵列。本申请实施例中，由图片源16传输至图片处理器的图片也可称为原始图片数据17。
图片预处理器18，用于接收原始图片数据17并对原始图片数据17执行预处理，以获取经预处理的图片19或经预处理的图片数据19。例如，图片预处理器18执行的预处理可以包括整修、色彩格式转换(例如，从RGB格式转换为YUV格式)、调色或去噪。
编码器20(或称视频编码器20)，用于接收经预处理的图片数据19，采用相关预测模式(如本文各个实施例中的预测模式)对经预处理的图片数据19进行处理，从而提供经编码图片数据21(下文将进一步基于图2或图4或图5描述编码器20的结构细节)。 在一些实施例中，编码器20可以用于执行后文所描述的各个实施例，以实现本申请所描述的帧间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视频解码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、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，通过存储器44实施的)图像缓冲器和图形处理单元。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方法主要用于帧间预测过程，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的当前图像块203)和经重构图片数据，例如来自缓冲器216的同一(当前)图片的参考样本和/或来自经解码图片缓冲器230的一个或多个先前经解码图片的参考图片数据231，以及用于处理这类数据进行预测，即提供可以为经帧间预测块245或经帧内预测块255的预测块265。
模式选择单元262可以用于选择预测模式(例如帧内或帧间预测模式)和/或对应的用作预测块265的预测块245或255，以计算残差块205和重构经重构块215。
模式选择单元262的实施例可以用于选择预测模式(例如，从预测处理单元260所支持的那些预测模式中选择)，所述预测模式提供最佳匹配或者说最小残差(最小残差意味着传输或存储中更好的压缩)，或提供最小信令开销(最小信令开销意味着传输或存储中更好的压缩)，或同时考虑或平衡以上两者。模式选择单元262可以用于基于码率失真优化(rate distortion optimization，RDO)确定预测模式，即选择提供最小码率失真优化的预测模式，或选择相关码率失真至少满足预测模式选择标准的预测模式。
下文将详细解释编码器20的实例(例如，通过预测处理单元260)执行的预测处理和(例如，通过模式选择单元262)执行的模式选择。
如上文所述，编码器20用于从(预先确定的)预测模式集合中确定或选择最好或最优的预测模式。预测模式集合可以包括例如帧内预测模式和/或帧间预测模式。
帧内预测模式集合可以包括35种不同的帧内预测模式，例如，如DC(或均值)模式和平面模式的非方向性模式，或如H.265中定义的方向性模式，或者可以包括67种不同的帧内预测模式，例如，如DC(或均值)模式和平面模式的非方向性模式，或如正在发展中的H.266中定义的方向性模式。
在可能的实现中，帧间预测模式集合取决于可用参考图片(即，例如前述存储在DBP230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。
具体的，在本申请实施例中，编码器20可用于实现后文实施例中描述的帧间预测方法。
应当理解的是，视频编码器20的其它的结构变化可用于编码视频流。例如，对于某些图像块或者图像帧，视频编码器20可以直接地量化残差信号而不需要经变换处理单元206处理，相应地也不需要经逆变换处理单元212处理；或者，对于某些图像块或者图像帧，视频编码器20没有产生残差数据，相应地不需要经变换处理单元206、量化单元208、逆量化单元210和逆变换处理单元212处理；或者，视频编码器20可以将经重构图像块作为参考块直接地进行存储而不需要经滤波器220处理；或者，视频编码器20中量化单元208和逆量化单元210可以合并在一起。环路滤波器220是可选的，以及针对无损压缩编码的情况下，变换处理单元206、量化单元208、逆量化单元210和逆变换处理单元212是可选的。应当理解的是，根据不同的应用场景，帧间预测单元244和帧内预测单元254可以是被选择性的启用。
参见图3，图3示出用于实现本申请实施例的解码器30的实例的示意性/概念性框图。视频解码器30用于接收例如由编码器20编码的经编码图片数据(例如，经编码比特流)21，以获取经解码图片231。在解码过程期间，视频解码器30从视频编码器20接收视频数据，例如表示经编码视频条带的图片块的经编码视频比特流及相关联的语法元素。
在图3的实例中，解码器30包括熵解码单元304、逆量化单元310、逆变换处理单元312、重构单元314(例如求和器314)、缓冲器316、环路滤波器320、经解码图片缓冲器330以及预测处理单元360。预测处理单元360可以包含帧间预测单元344、帧内预测单元354和模式选择单元362。在一些实例中，视频解码器30可执行大体上与参照图2 的视频编码器20描述的编码遍次互逆的解码遍次。
熵解码单元304用于对经编码图片数据21执行熵解码，以获取例如经量化系数309和/或经解码的编码参数(图3中未示出)，例如，帧间预测、帧内预测参数、环路滤波器参数和/或其它语法元素中(经解码)的任意一个或全部。熵解码单元304进一步用于将帧间预测参数、帧内预测参数和/或其它语法元素转发至预测处理单元360。视频解码器30可接收视频条带层级和/或视频块层级的语法元素。
逆量化单元310功能上可与逆量化单元110相同，逆变换处理单元312功能上可与逆变换处理单元212相同，重构单元314功能上可与重构单元214相同，缓冲器316功能上可与缓冲器216相同，环路滤波器320功能上可与环路滤波器220相同，经解码图片缓冲器330功能上可与经解码图片缓冲器230相同。
预测处理单元360可以包括帧间预测单元344和帧内预测单元354，其中帧间预测单元344功能上可以类似于帧间预测单元244，帧内预测单元354功能上可以类似于帧内预测单元254。预测处理单元360通常用于执行块预测和/或从经编码数据21获取预测块365，以及从例如熵解码单元304(显式地或隐式地)接收或获取预测相关参数和/或关于所选择的预测模式的信息。
当视频条带经编码为经帧内编码(I)条带时，预测处理单元360的帧内预测单元354用于基于信号表示的帧内预测模式及来自当前帧或图片的先前经解码块的数据来产生用于当前视频条带的图片块的预测块365。当视频帧经编码为经帧间编码(即B或P)条带时，预测处理单元360的帧间预测单元344(例如，运动补偿单元)用于基于运动向量及从熵解码单元304接收的其它语法元素生成用于当前视频条带的视频块的预测块365。对于帧间预测，可从一个参考图片列表内的一个参考图片中产生预测块。视频解码器30可基于存储于DPB 330中的参考图片，使用默认建构技术来建构参考帧列表：列表0和列表1。
预测处理单元360用于通过解析运动向量和其它语法元素，确定用于当前视频条带的视频块的预测信息，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帧间预测方法。
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当前图像块的控制点的运动矢量，或者推导得到的当前图像块的子块的运动矢量，可以经过进一步处理，本申请对此不做限定。例如，对运动矢量的取值范围进行约束，使其在一定的位宽内。假设允许的运动矢量的位宽为bitDepth，则运动矢量的范围为-2 bitDepth-1～2 bitDepth-1-1。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8×8图像块内的四个4×4子块的运动矢量MV)的取值进行约束，使得所述四个4×4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。
参见图4，图4是本申请实施例提供的视频译码设备400(例如视频编码设备400或视频解码设备400)的结构示意图。视频译码设备400适于实施本文所描述的实施例。在一个实施例中，视频译码设备400可以是视频解码器(例如图1A的解码器30)或视频编 码器(例如图1A的编码器20)。在另一个实施例中，视频译码设备400可以是上述图1A的解码器30或图1A的编码器20中的一个或多个组件。
视频译码设备400包括：用于接收数据的入口端口410和接收单元(Rx)420，用于处理数据的处理器、逻辑单元或中央处理器(CPU)430，用于传输数据的发射器单元(Tx)440和出口端口450，以及，用于存储数据的存储器460。视频译码设备400还可以包括与入口端口410、接收器单元420、发射器单元440和出口端口450耦合的光电转换组件和电光(EO)组件，用于光信号或电信号的出口或入口。
处理器430通过硬件和软件实现。处理器430可以实现为一个或多个CPU芯片、核(例如，多核处理器)、FPGA、ASIC和DSP。处理器430与入口端口410、接收器单元420、发射器单元440、出口端口450和存储器460通信。处理器430包括译码模块470(例如编码模块470或解码模块470)。编码/解码模块470实现本文中所公开的实施例，以实现本申请实施例所提供的帧间预测方法。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。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帧间预测方法)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。
图6描述了四叉树，二叉树及扩展四叉树的划分方式，其中：
QT是一种树状结构，表示一个节点可划分为四个子节点。现有视频编码标准采用基于四叉树的CTU划分方式：CTU作为根节点，每个节点对应于一个方形的区域；一个节点可以不再划分(此时它对应的区域为一个CU)，或者将这个节点划分成四个下一层级的节点，即把这个方形区域划分成四个大小相同的方形区域(其长、宽各为划分前区域长、宽的一半)，每个区域对应于一个节点。如6(a)所示。
二叉树是一种树状结构，表示一个节点可划分成两个子节点。现有采用二叉树的编码方法中，一个二叉树结构上的节点可以不划分，或者把此节点划分成两个下一层级的节点。划分成两个节点的方式有两种：1)水平二分，将节点对应的区域划分成上、下两个相同大小的区域，每个区域对应于一个节点，如6(b)所示；或者2)竖直二分，将节点对应的区域划分成左、右两个大小相同的区域，每个区域对应于一个节点，如6(c)所示。
扩展四叉树(Extended Quad-Tree，EQT)是一种工字划分结构，一个节点可划分成四个子节点。划分成三个节点的方式有两种：1)水平四分，将节点对应的区域划分成上、中、下三个区域，每个区域对应于一个节点，其中上、中左、中右、下三个区域的高分别为节点高的1/4、1/2、1/2、1/4，中左和中右宽度为节点高度的1/2、1/2，如6(d)所示；或者2)竖直四分，将节点对应的区域划分成左、中上、中下、右三个区域，每个区域对应于一个节点，其中左、中、右三个区域的宽分别为节点高的1/4、1/2、1/2、1/4，中上和中下宽度为节点高度的1/2、1/2，如6(e)所示。现有采用扩展四叉树的编码方法中，一个扩展四叉树结构上的节点可以不划分，或者把此节点按BT或EQT的方式继续划分成下一层级的节点。
H.265视频编码标准把一帧图像分割成互不重叠的编码树单元(CTU)，CTU的大小可设置为64×64(CTU的大小也可设置为其它值，如JVET参考软件JEM中CTU大小增大为128×128或256×256)。64×64的CTU包含由64列、每列64个像素的矩形像素点阵，每个像素包含亮度分量或/和色度分量。
使用基于四叉树(quad-tree，简称QT)的CTU划分方法，将CTU作为四叉树的根节点(root)，按照四叉树的划分方式，将CTU递归划分成若干个叶节点(leaf node)。一个节点对应于一个图像区域，节点如果不划分，则节点称为叶节点，它对应的图像区域形成一个CU；如果节点继续划分，则节点对应的图像区域划分成四个相同大小的区域(其长和宽各为被划分区域的一半)，每个区域对应一个节点，需要分别确定这些节点是否还会划分。一个节点是否划分由码流中这个节点对应的划分标志位split_cu_flag指示。一个节点A划分一次得到4个节点Bi，i＝0,1,2,3，Bi称为A的子节点，A称为Bi的父节点。根节点的四叉树层级(qtDepth)为0，节点的四叉树层级为节点的父节点的四叉树层级加 1。为表述简洁，下文中节点的大小和形状即指节点对应的图像区域的大小和形状。
更具体的，对64×64的CTU节点(四叉树层级为0)，根据它对应的split_cu_flag，可选择不划分，成为1个64×64的CU，或者选择划分为4个32×32的节点(四叉树层级为1)。这四个32×32的节点中的每一个节点，又可以根据它对应的split_cu_flag，选择继续划分或者不划分；如果一个32×32的节点继续划分，则产生四个16×16的节点(四叉树层级为2)。以此类推，直到所有节点都不再划分，这样一个CTU就被划分成一组CU。CU的最小尺寸(size)在序列参数集(Sequence Parameter Set，SPS)中标识，例如8×8为最小CU。在上述递归划分过程中，如果一个节点的尺寸等于最小CU尺寸(minimum CU size)，这个节点默认为不再划分，同时也不需要在码流中包含它的划分标志位。
当解析到一个节点为叶节点后，此叶节点为一个CU，进一步解析CU对应的编码信息(包括CU的预测模式、变换系数等信息，例如H.265中的coding_unit()语法结构体)，然后按照这些编码信息对CU进行预测、反量化、反变换、环路滤波等解码处理，产生这个CU对应的重建图像。四叉树结构使得CTU能够根据图像局部特点划分成合适大小的一组CU，例如平滑区域划分成较大的CU，而纹理丰富区域划分为较小的CU。
一种CTU划分成一组CU的划分方式对应于一个编码树(coding tree)。CTU应当采用何种编码树则通常通过编码器的率失真优化(rate distortion optimization，RDO)技术来确定。编码器尝试多种CTU划分方式，每一种划分方式对应于一个率失真代价(RD cost)；编码器比较各种尝试过的划分方式的RD cost，找到RD cost最小的划分方式，作为该CTU最优的划分方式，用于该CTU的实际编码。编码器尝试的各种CTU划分方式均需要符合解码器规定的划分规则，这些才能够被解码器正确识别。
多用途视频编码测试模型(Versatile video coding Test Model，VTM)参考软件在四叉树划分的基础上，增加了二叉树(binary tree，BT)划分方式和三叉树(ternary tree，TT)划分方式。其中，VTM是JVET组织开发的新式编解码器参考软件。
二叉树划分将一个节点划分成2个子节点，具体的二叉树划分方式有两种：
1)水平二分：将节点对应的区域划分成上、下两个相同大小的区域(即宽不变，高变为划分前区域的一半)，每个区域对应于一个节点；如6(b)所示。
2)竖直二分：将节点对应的区域划分成左、右两个相同大小的区域(即高不变，宽变为划分前区域的一半)；如6(c)所示。
三叉树划分将一个节点划分成3个子节点，具体的三叉树划分方式有两种：
1)水平三分：将节点对应的区域划分成上、中、下三个区域，每个区域对应于一个节点，其中上、中、下三个区域的高分别为节点高的1/4、1/2、1/4，如6(d)所示；
2)竖直三分：将节点对应的区域划分成左、中、右三个区域，每个区域对应于一个节点，其中左、中、右三个区域的宽分别为节点高的1/4、1/2、1/4，如6(e)所示
VTM中使用了QT级联BT/TT的划分方式(Quad Tree plus Multi-Type Tree，QT-MTT)划分方式。更具体的，CTU通过QT划分，产生QT叶节点，QT中的节点可使用四叉树划分继续划分成四个QT子节点，或者不使用四叉划分产生一个QT叶节点。QT叶节点作为MTT的根节点。MTT中的节点可使用水平二分、竖直二分、水平三分、竖直三分这四种划分方式中的一种划分为子节点，或者不再划分成为一个MTT叶节点。MTT的叶节点为一个编码单元CU。
图7给出了使用QT-MTT将一个CTU划分成a到p等16个CU的示例。图7右图中每个端点表示一个节点，一个节点连出4根线表示四叉树划分，一个节点连出2根线表示二叉树划分，一个节点连出3根线表示三叉树划分。实线表示QT划分，虚线表示多类型划分(Multi-Type Tree，MTT)的第一层划分，点划线表示MTT的第二层划分。a到p为16个MTT叶节点，每个MTT叶节点为1个CU。一个CTU按照图7右图的划分方式，得到了如图7左图所示的CU划分图。
QT-MTT划分方式中，每个CU具有QT层级(Quad-tree depth，QT depth，也称为QT深度)和MTT层级(Multi-Type Tree depth，MTT depth，也称为MTT深度)。QT层级表示CU所属的QT叶节点的QT层级，MTT层级表示CU所属MTT叶节点的MTT层级。编码树的根节点的QT层级为0，MTT层级为0。如果编码树上一个节点使用QT划分，则划分得到的子节点的QT层级为该节点的QT层级加1，MTT层级不变；相似的，如果编码树上一个节点使用MTT划分(即BT或TT划分之一)，则划分得到的子节点的MTT层级为该节点的MTT层级加1，QT层级不变。例如图1中a、b、c、d、e、f、g、i、j的QT层级为1，MTT层级为2；h的QT层级为1，MTT层级为1；n、o、p的QT层级为2，MTT层级为0；l、m的QT层级为2，MTTT层级为1。如果CTU只划分成一个CU，则此CU的QT层级为0，MTT层级为0。
在最新的AVS3的制定过程中，AVS3在四叉树划分的基础上，增加了二叉树(binary tree，BT)划分方式和扩展四叉树(Extended Quad-Tree，EQT)划分方式。
二叉树划分将一个节点划分成2个子节点，具体的两叉树划分方式有两种：
1)水平二分(horizontal binary tree，HBT)：将节点对应的区域划分成上、下两个相同大小的区域(即宽不变，高变为划分前区域的一半)，每个区域对应于一个节点；如6(b)所示。
2)竖直二分(vertical binary tree，VBT)：将节点对应的区域划分成左、右两个相同大小的区域(即高不变，宽变为划分前区域的一半)；如6(c)所示。
扩展四叉树划分将一个节点划分成4个子节点，具体的扩展四叉树划分方式有两种：
1)水平四分(horizontal Extended Quad-Tree，HEQT)，将节点对应的区域划分成上、中、下三个区域，每个区域对应于一个节点，其中上、中左、中右、下三个区域的高分别为节点高的1/4、1/2、1/2、1/4，中左和中右宽度为节点高度的1/2、1/2，如6(d)所示；
2)竖直四分(vertical Extended Quad-Tree，VEQT)，将节点对应的区域划分成左、中上、中下、右三个区域，每个区域对应于一个节点，其中左、中、右三个区域的宽分别为节点高的1/4、1/2、1/2、1/4，中上和中下宽度为节点高度的1/2、1/2，如6(e)所示。
AVS3中使用了QT级联BT/EQT的划分方式，即第一级编码树上的节点只能使用QT划分成子节点，第一级编码树的叶节点为第二级编码树的根节点；第二级编码树上的节点可使用BT或EQT划分方式中的一种划分为子节点；第二级编码树的叶节点为编码单元。需要注意的是，当叶节点为BT或EQT划分方式时，其叶节点只能使用BT或EQT划分方式，而不能使用QT的方式。
经过上述的各种划分之后，编码树下的叶子节点位置的图像块作为编码单元，视频编码主要包括帧内预测(Intra Prediction)、帧间预测(Inter Prediction)、变换(Transform)、 量化(Quantization)、熵编码(Entropy encode)、环内滤波(in-loop filtering)(主要为去块滤波，de-blocking filtering)等环节。将图像划分为编码块之后进行帧内预测或者帧间预测，并且在得到残差之后进行变换量化，最终进行熵编码并输出码流。此处编码块为由像素点组成的M×N大小的阵列(M可以等于N，也可以不等于N)，并且已知各个像素点位置的像素值。
帧内预测是指利用当前图像内已重建区域内像素点的像素值对当前编码块内像素点的像素值进行预测。
帧间预测是在已重建的图像中，为当前图像中的当前编码块寻找匹配的参考块，从而得到当前编码块的运动信息，然后根据运动信息计算出当前编码块中像素点的像素值的预测信息或者预测值(以下不再区分信息和值)。其中，计算运动信息的过程称为运动估计(Motion estimation，ME)，计算出当前编码块中像素点的像素值的预测值的过程称为运动补偿(Motion compensation，MC)。
需要说明的是，当前编码块的运动信息包括了预测方向的指示信息(通常为前向预测、后向预测或者双向预测)，一个或两个指向参考块的运动矢量(Motion vector，MV)，以及参考块所在图像的指示信息(通常记为参考帧索引，Reference index)。
前向预测是指当前编码块从前向参考图像集合中选择一个参考图像获取参考块。后向预测是指当前编码块从后向参考图像集合中选择一个参考图像获取参考块。双向预测是指从前向和后向参考图像集合中各选择一个参考图像获取参考块。当使用双向预测方法时，当前编码块会存在两个参考块，每个参考块各自需要运动矢量和参考帧索引进行指示，然后根据两个参考块内像素点的像素值确定当前块内像素点像素值的预测值。
运动估计过程需要为当前编码块在参考图像中尝试多个参考块，最终使用哪一个或者哪几个参考块用作预测则使用率失真优化(Rate-distortion optimization，RDO)或者其他方法确定。
利用帧内预测或者帧间预测得到预测信息之后，当前编码块内像素点的像素值减去对应的预测信息便得到残差信息，然后利用离散余弦变换(Discrete Cosine Transformation，DCT)等方法对残差信息进行变换，再使用量化熵编码得到码流。预测信号加上重建残差信号之后需进一步进行滤波操作，进而得到重建信号，并将其作为后续编码的参考信号。
解码则相当于编码的逆过程。例如，首先利用熵解码反量化反变换得到残差信息，解码码流以确定当前编码块使用的是帧内预测还是帧间预测。如果是帧内预测，则利用周围已重建区域内像素点的像素值按照所使用的帧内预测方法构建预测信息。如果是帧间预测，则需要解析出运动信息，并使用所解析出的运动信息在已重建的图像中确定参考块，并将块内像素点的像素值作为预测信息，此过程称为运动补偿(Motion compensation，MC)。使用预测信息加上残差信息经过滤波操作便可以得到重建信息。
下述实施例为根据当前图像块的码流确定当前图像块的预测模式的过程。
图8是示出根据本申请一种实施例的预测模式确定方法的流程图。该过程800可由视频编码器20或视频解码器30执行。过程800描述为一系列的步骤或操作，应当理解的是，过程800可以以各种顺序执行和/或同时发生，不限于图8所示的执行顺序。如图8所示，该方法包括：
步骤801、确定当前图像块的划分方式。
当前图像块的划分方式可以是QT划分方式、BT划分方式、EQT划分方式或其他划分方式，本申请不做限定。当前图像块的划分方式通常会在编码后携带于码流中传输，通过解析码流中相应的语法元素就可以获取当前图像块的划分方式。
需要说明的是，当前图像块也可能不需要再划分，那么当前图像块就作为编码单元进行处理。
步骤802、判断使用划分方式对当前图像块进行划分后是否会得到满足预设条件的第一图像子块。
本申请中预设条件可以包括第一图像子块的面积小于或者等于设定的阈值。即该步骤可以基于当前图像块的面积来判断，即若当前图像块的面积满足以下任一条件，则确定划分后会得到第一图像子块：当划分方式为二叉树BT划分方式时，sizeC/2小于S，sizeC为当前图像块的面积，S为预设面积阈值；或者，当划分方式为四叉树QT划分方式时，sizeC/4小于S；或者，当划分方式为扩展四叉树EQT划分方式时，sizeC/4小于S。
本申请要预判对当前图像块划分后是否会得到面积小于设定阈值的第一图像子块，那么根据步骤801中得到的划分方式就可以提前知道划分后各图像子块的面积，如果是BT划分方式，当前图像块被分为2个图像子块，因此判断sizeC/2是否小于S；如果是QT划分方式，当前图像块被分为4个图像子块，因此判断sizeC/4是否小于S；如果是EQT划分方式，当前图像块被分为4个图像子块，因此判断sizeC/4是否小于S。
另外，本申请还可以根据划分后得到的多个图像子块的面积分别与设定阈值进行比较，其中有一个或多个图像子块的面积小于该设定阈值，就可以确定划分后会得到第一图像子块，该面积小于该设定阈值的图像子块就是第一图像子块。需要说明的是，本申请可以采用多种方法来确定对图像子块划分后是否会得到第一图像子块，对比不做具体限定。
示例性的，假设当前图像块的宽为W，高为H，则当前图像块的面积sizeC＝W×H，S可以设定为64或者32。
步骤803、若判断划分后会得到第一图像子块，则使用划分方式对当前图像块进行划分得到多个图像子块。
划分后得到的多个图像子块必然包括上述第一图像子块。
步骤804、确定多个图像子块采用相同的预测模式，该多个图像子块的预测模式同为帧内预测模式或帧间预测模式。
本申请将划分出来的多个图像子块的预测模式同确定为帧内预测模式或帧间预测模式，就无需解析所有码流，可以调高效率。该过程可以包括解析当前图像块的码流确定第二图像子块的预测模式，第二图像子块为多个图像子块中按照处理顺序第一个确定为CU的图像子块；根据第二图像子块的预测模式确定多个图像子块中除第二图像子块外的其他图像子块的预测模式。需要说明的是，该过程也可以采用其他方法，本申请对此不做具体限定。
上述第二图像子块是当前图像块划分后得到的多个图像子块中按照处理顺序第一个确定被为CU的图像子块，解析码流就可以知道该图像子块的划分方式，如果图像子块不再划分，则该图像子块就确定是CU。而在面对多个图像子块时，编码设备或解码设备有预先设定的处理顺序，按照这个顺序第一个被为CU的图像子块就是第二图像子块。
需要说明的是，本申请对步骤802和步骤803没有明确的执行顺序限定，除了上述方法实施例中说明的执行过程外，本申请提供的预测模式确定方法，还可以在确定当前图像块的划分方式之后，先使用该划分方式对当前图像块进行划分得到多个图像子块，然后判断划分得到的多个图像子块中是否包括第一图像子块，该第一图像子块的面积小于设定阈值，最后确定多个图像子块的预测模式。
本申请实施例中预测模式分为帧内预测模式和帧间预测模式，帧间预测模式包括跳过模式(Skip Mode)、直接模式(Direct Mode)或普通帧间模式。
图9是示出根据本申请一种实施例的预测模式确定方法的流程图。该过程900确定了第二图像子块的预测模式。过程900可由视频编码器20或视频解码器30执行。过程900描述为一系列的步骤或操作，应当理解的是，过程900可以以各种顺序执行和/或同时发生，不限于图9所示的执行顺序。如图9所示，该方法包括：
步骤901、对码流进行解析获取skip_flag。
skip_flag为第二图像子块的跳过模式标识，skip_flag＝1表示第二图像子块使用跳过模式，skip_flag＝0表示第二图像子块不使用跳过模式。skipFlag的值等于skip_flag的值。如果位流不存在skip_flag，则skipFlag的值等于0。
步骤902、根据skipFlag判断第二图像子块的预测模式是否为跳过模式。
skipFlag＝1执行步骤903，skipFlag＝0执行步骤904。
步骤903、确定第二图像子块的预测模式为跳过模式。
执行到步骤903已经确定了第二图像子块的预测模式，此时只从码流中解析skip_flag，不需要从码流中解析direct_flag和cu_pred_mode，即无需解析所有码流。
步骤904、对码流进行解析获取direct_flag。
direct_flag为第二图像子块的直接模式标识，direct_flag＝1表示第二图像子块使用直接模式，direct_flag＝0表示第二图像子块不使用直接模式。directFlag的值等于direct_flag的值。如果位流中不存在direct_flag，则directFlag的值等于0。
步骤905、根据directFlag判断第二图像子块的预测模式是否为直接模式。
directFlag＝1执行步骤906，directFlag＝0执行步骤907。
步骤906、确定第二图像子块的预测模式为直接模式。
执行到步骤906已经确定了第二图像子块的预测模式，此时只从码流中解析skip_flag和direct_flag，不需要从码流中解析cu_pred_mode，即无需解析所有码流。
步骤907、对码流进行解析获取cu_pred_mode。
cu_pred_mode为第二图像子块的预测模式标识，cu_pred_mode＝1表示第二图像子块使用帧内预测模式，cu_pred_mode＝0表示第二图像子块使用普通帧间预测模式。CuPredMode的值等于cu_pred_mode，如果位流中不存在cu_pred_mode且当前帧为I帧，则CuPredMode等于1。
步骤908、根据CuPredMode判断第二图像子块的预测模式是否为帧内预测模式。
CuPredMode＝1执行步骤909，CuPredMode＝0执行步骤910。
步骤909、确定第二图像子块的预测模式为帧内预测模式。
步骤910、确定第二图像子块的预测模式为普通帧间模式。
执行到步骤910确定了第二图像子块的预测模式，此时从码流中解析全部标识 skip_flag、direct_flag和cu_pred_mode。
图10是示出根据本申请一种实施例的预测模式确定方法的流程图。该过程1000确定了除第二图像子块外其他图像子块的预测模式。过程1000可由视频编码器20或视频解码器30执行。过程1000描述为一系列的步骤或操作，应当理解的是，过程1000可以以各种顺序执行和/或同时发生，不限于图10所示的执行顺序。如图10所示，该方法包括：
步骤1001、当第二图像子块的预测模式为帧间预测模式时，对码流进行解析获取skip_flag。
skip_flag为其他图像子块的跳过模式标识，skip_flag＝1表示其他图像子块使用跳过模式，skip_flag＝0表示其他图像子块不使用跳过模式。skipFlag的值等于skip_flag的值。如果位流不存在skip_flag，则skipFlag的值等于0。
步骤1002、根据skipFlag判断其他图像子块的预测模式是否为跳过模式。
skipFlag＝1执行步骤1003，skipFlag＝0执行步骤1004。
步骤1003、确定其他图像子块的预测模式为跳过模式。
执行到步骤1003已经确定了其他图像子块的预测模式，此时只从码流中解析skip_flag，不需要从码流中解析direct_flag和cu_pred_mode，即无需解析所有码流。
步骤1004、对码流进行解析获取direct_flag。
direct_flag为其他图像子块的直接模式标识，direct_flag＝1表示其他图像子块使用直接模式，direct_flag＝0表示其他图像子块不使用直接模式。directFlag的值等于direct_flag的值。如果位流中不存在direct_flag，则directFlag的值等于0。
步骤1005、根据directFlag判断其他图像子块的预测模式是否为直接模式。
directFlag＝1执行步骤1006，directFlag＝0执行步骤1007。
步骤1006、确定其他图像子块的预测模式为直接模式。
执行到步骤1006已经确定了其他图像子块的预测模式，此时只从码流中解析skip_flag和direct_flag，不需要从码流中解析cu_pred_mode，即无需解析所有码流。
步骤1007、确定其他图像子块的预测模式为普通帧间模式。
由于第二图像子块使用的帧间预测模式，那么其他图像子块为了保持一致，只在帧间预测模式中选择预测模式，执行到步骤1007只剩下普通帧间模式，那么就确定其他图像子块的预测模式为普通帧间模式，不需要从码流中解析cu_pred_mode。
步骤1008、当第二图像子块的预测模式为帧内预测模式时，对码流进行解析确定其他图像子块的预测模式为帧内预测模式的其中一种。
示例性的，帧内预测模式包括帧内亮度预测模式和帧内色度预测模式，可以通过两个标识确定其他图像子块的预测模式为帧内预测模式的哪一种，即intra_luma_prediction_mode用于确定亮度块的帧内预测模式，其取值范围为0-32。intra_chroma_prediction_mode用于确定4:2:0格式的编码块中PredBlockOrder为NumOfIntraPredBlock、NumOfIntraPredBlock+1的两个色度块的帧内预测模式。
由于第一图像子块使用的帧内预测模式，那么其他图像子块为了保持一致，只能使用帧内预测模式。执行到步骤1008不需要从码流中解析任何标识就可以确定其他图像子块的预测模式。
本申请实施例在根据当前图像块的码流确定当前图像块的预测模式的过程中，基于当 前图像块划分出的其中一个图像子块的预测模式确定面积较小的图像子块的预测模式，从而无需解析所有码流，而且对于面积小的图像子块使用和其他图像子块相同的预测模式，便于硬件的流水处理。
需要说明的是，上述实施例中涉及到的多个标识变量或名称均是一种示例性说明，其还可以采用其他任意格式或名称来表示，本申请对此不作具体限定。
图11为本申请实施例中的预测模式确定装置1100的一种示意性框图。该预测模式确定装置1100可以包括：确定模块1101、判断模块1102、划分模块1103和预测模块1104，其中，确定模块1101，用于确定当前图像块的划分方式；判断模块1102，用于判断使用所述划分方式对所述当前图像块进行划分后是否会得到满足预设条件的第一图像子块；划分模块1103，用于若判断划分后会得到所述第一图像子块，则使用所述划分方式对所述当前图像块进行划分得到多个图像子块，所述多个图像子块包括所述第一图像子块；预测模块1104，用于确定所述多个图像子块采用相同的预测模式，所述多个图像子块的预测模式同为帧内预测模式或帧间预测模式。
在一种可能的实现方式中，所述的预设条件包括所述第一图像子块的面积小于或者等于设定的阈值。
在一种可能的实现方式中，所述预测模块1104，具体用于解析所述当前图像块的码流确定第二图像子块的预测模式，所述第二图像子块为所述多个图像子块中第一个确定为编码单元CU的图像子块，所述第二图像子块的预测模式为所述帧内预测模式或所述帧间预测模式；根据所述第二图像子块的预测模式确定所述多个图像子块中除所述第二图像子块外的其他图像子块的预测模式，所述其他图像子块的预测模式与所述第二图像子块的预测模式同为所述帧内预测模式或所述帧间预测模式。
在一种可能的实现方式中，所述帧间预测模式包括跳过模式、直接模式或普通帧间模式。
在一种可能的实现方式中，所述预测模块1104，具体用于当所述第二图像子块的预测模式为所述帧间预测模式时，解析所述码流获取所述其他图像子块的跳过模式标识，并根据所述跳过模式标识判断所述其他图像子块的预测模式是否为所述跳过模式；若所述跳过模式标识指示使用所述跳过模式，则确定所述其他图像子块的预测模式为所述跳过模式。
在一种可能的实现方式中，所述预测模块1104，还用于若所述跳过模式标识指示不使用所述跳过模式，则解析所述码流获取所述其他图像子块的直接模式标识，并根据所述直接模式标识判断所述其他图像子块的预测模式是否为所述直接模式；若所述直接模式标识指示使用所述直接模式，则确定所述其他图像子块的预测模式为所述直接模式；若所述直接模式标识指示不使用所述直接模式，则确定所述其他图像子块的预测模式为所述普通帧间模式。
在一种可能的实现方式中，所述预测模块1104，具体用于当所述第二图像子块的预测模式为所述帧内预测模式时，解析所述码流确定所述其他图像子块的预测模式为所述帧内预测模式的其中一种。
在一种可能的实现方式中，所述判断模块1102，具体用于若所述当前图像块的面积满足以下条件，则确定划分后会得到所述第一图像子块：当所述划分方式为二叉树BT划 分方式时，sizeC/2小于S，sizeC为所述当前图像块的面积，S为预设面积阈值；或者，当所述划分方式为四叉树QT划分方式时，sizeC/4小于S；或者，当所述划分方式为扩展四叉树EQT划分方式时，sizeC/4小于S。
在一种可能的实现方式中，所述划分模块1103，还用于若判断划分后不会得到所述第一图像子块，则使用所述划分方式对所述当前图像块进行划分得到多个图像子块，并分别确定所述多个图像子块的划分方式，对各所述图像子块使用对应的划分方式分别进行划分。
在一种可能的实现方式中，所述预测模块1104，具体用于解析所述码流获取所述第二图像子块的跳过模式标识，并根据所述跳过模式标识判断所述第二图像子块的预测模式是否为所述跳过模式；若所述跳过模式标识指示使用所述跳过模式，则确定所述第二图像子块的预测模式为所述跳过模式。
在一种可能的实现方式中，所述预测模块1104，还用于若所述跳过模式标识指示不使用所述跳过模式，则解析所述码流获取所述第二图像子块的直接模式标识，并根据所述直接模式标识判断所述第二图像子块的预测模式是否为所述直接模式；若所述直接模式标识指示使用所述直接模式，则确定所述第二图像子块的预测模式为所述直接模式。
在一种可能的实现方式中，所述预测模块1104，还用于若所述直接模式标识指示不使用所述直接模式，则解析所述码流所述第二图像子块的预测模式标识，并根据所述预测模式标识判断所述第二图像子块的预测模式是否为所述帧内预测模式；若所述预测模式标识指示使用所述帧内预测模式，则确定所述第二图像子块的预测模式为所述帧内预测模式；若所述预测模式标识指示使用普通帧间模式，则确定所述第二图像子块的预测模式为所述普通帧间模式。
需要说明的是，本申请实施例的帧间预测装置中的各个模块为实现本申请帧间预测方法中所包含的各种执行步骤的功能主体，即具备实现完整实现本申请帧间预测方法中的各个步骤以及这些步骤的扩展及变形的功能主体，具体请参见本文中对帧间预测方法的介绍，为简洁起见，本文将不再赘述。
本领域技术人员能够领会，结合本文公开描述的各种说明性逻辑框、模块和算法步骤所描述的功能可以硬件、软件、固件或其任何组合来实施。如果以软件来实施，那么各种说明性逻辑框、模块、和步骤描述的功能可作为一或多个指令或代码在计算机可读媒体上存储或传输，且由基于硬件的处理单元执行。计算机可读媒体可包含计算机可读存储媒体，其对应于有形媒体，例如数据存储媒体，或包括任何促进将计算机程序从一处传送到另一处的媒体(例如，根据通信协议)的通信媒体。以此方式，计算机可读媒体大体上可对应于(1)非暂时性的有形计算机可读存储媒体，或(2)通信媒体，例如信号或载波。数据存储媒体可为可由一或多个计算机或一或多个处理器存取以检索用于实施本申请中描述的技术的指令、代码和/或数据结构的任何可用媒体。计算机程序产品可包含计算机可读媒体。
作为实例而非限制，此类计算机可读存储媒体可包括RAM、ROM、EEPROM、CD-ROM或其它光盘存储装置、磁盘存储装置或其它磁性存储装置、快闪存储器或可用来存储指令或数据结构的形式的所要程序代码并且可由计算机存取的任何其它媒体。并且，任何连接 被恰当地称作计算机可读媒体。举例来说，如果使用同轴缆线、光纤缆线、双绞线、数字订户线(DSL)或例如红外线、无线电和微波等无线技术从网站、服务器或其它远程源传输指令，那么同轴缆线、光纤缆线、双绞线、DSL或例如红外线、无线电和微波等无线技术包含在媒体的定义中。但是，应理解，所述计算机可读存储媒体和数据存储媒体并不包括连接、载波、信号或其它暂时媒体，而是实际上针对于非暂时性有形存储媒体。如本文中所使用，磁盘和光盘包含压缩光盘(CD)、激光光盘、光学光盘、数字多功能光盘(DVD)和蓝光光盘，其中磁盘通常以磁性方式再现数据，而光盘利用激光以光学方式再现数据。以上各项的组合也应包含在计算机可读媒体的范围内。
可通过例如一或多个数字信号处理器(DSP)、通用微处理器、专用集成电路(ASIC)、现场可编程逻辑阵列(FPGA)或其它等效集成或离散逻辑电路等一或多个处理器来执行指令。因此，如本文中所使用的术语“处理器”可指前述结构或适合于实施本文中所描述的技术的任一其它结构中的任一者。另外，在一些方面中，本文中所描述的各种说明性逻辑框、模块、和步骤所描述的功能可以提供于经配置以用于编码和解码的专用硬件和/或软件模块内，或者并入在组合编解码器中。而且，所述技术可完全实施于一或多个电路或逻辑元件中。
本申请的技术可在各种各样的装置或设备中实施，包含无线手持机、集成电路(IC)或一组IC(例如，芯片组)。本申请中描述各种组件、模块或单元是为了强调用于执行所揭示的技术的装置的功能方面，但未必需要由不同硬件单元实现。实际上，如上文所描述，各种单元可结合合适的软件和/或固件组合在编码解码器硬件单元中，或者通过互操作硬件单元(包含如上文所描述的一或多个处理器)来提供。
在上述实施例中，对各个实施例的描述各有侧重，某个实施例中没有详述的部分，可以参见其他实施例的相关描述。
以上所述，仅为本申请示例性的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到的变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应该以权利要求的保护范围为准。

Claims (26)

  1. 一种预测模式确定方法，其特征在于，包括：
    确定当前图像块的划分方式；
    判断使用所述划分方式对所述当前图像块进行划分后是否会得到满足预设条件的第一图像子块；
    若判断划分后会得到所述第一图像子块，则使用所述划分方式对所述当前图像块进行划分得到多个图像子块，所述多个图像子块包括所述第一图像子块；
    确定所述多个图像子块采用相同的预测模式，所述多个图像子块的预测模式同为帧内预测模式或帧间预测模式。
  2. 根据权利要求1所述的方法，其特征在于，所述的预设条件包括所述第一图像子块的面积小于或者等于设定的阈值。
  3. 根据权利要求1或2所述的方法，其特征在于，所述确定所述多个图像子块采用相同的预测模式，包括：
    解析所述当前图像块的码流确定第二图像子块的预测模式，所述第二图像子块为所述多个图像子块中第一个确定为编码单元CU的图像子块，所述第二图像子块的预测模式为所述帧内预测模式或所述帧间预测模式；
    根据所述第二图像子块的预测模式确定所述多个图像子块中除所述第二图像子块外的其他图像子块的预测模式，所述其他图像子块的预测模式与所述第二图像子块的预测模式同为所述帧内预测模式或所述帧间预测模式。
  4. 根据权利要求3所述的方法，其特征在于，所述帧间预测模式包括跳过模式、直接模式或普通帧间模式。
  5. 根据权利要求4所述的方法，其特征在于，所述根据所述第二图像子块的预测模式确定所述多个图像子块中除所述第二图像子块外的其他图像子块的预测模式，包括：
    当所述第二图像子块的预测模式为所述帧间预测模式时，解析所述码流获取所述其他图像子块的跳过模式标识，并根据所述跳过模式标识判断所述其他图像子块的预测模式是否为所述跳过模式；
    若所述跳过模式标识指示使用所述跳过模式，则确定所述其他图像子块的预测模式为所述跳过模式。
  6. 根据权利要求5所述的方法，其特征在于，所述根据所述第二图像子块的预测模式确定所述多个图像子块中除所述第二图像子块外的其他图像子块的预测模式，还包括：
    若所述跳过模式标识指示不使用所述跳过模式，则解析所述码流获取所述其他图像子块的直接模式标识，并根据所述直接模式标识判断所述其他图像子块的预测模式是否为所述直接模式；
    若所述直接模式标识指示使用所述直接模式，则确定所述其他图像子块的预测模式为所述直接模式；
    若所述直接模式标识指示不使用所述直接模式，则确定所述其他图像子块的预测模式为所述普通帧间模式。
  7. 根据权利要求4-6中任一项所述的方法，其特征在于，所述根据所述第二图像子 块的预测模式确定所述多个图像子块中除所述第二图像子块外的其他图像子块的预测模式，包括：
    当所述第二图像子块的预测模式为所述帧内预测模式时，解析所述码流确定所述其他图像子块的预测模式为所述帧内预测模式的其中一种。
  8. 根据权利要求1-7中任一项所述的方法，其特征在于，所述判断使用所述划分方式对所述当前图像块进行划分后是否会得到满足预设条件的第一图像子块，包括：
    若所述当前图像块的面积满足以下条件，则确定划分后会得到所述第一图像子块：
    当所述划分方式为二叉树BT划分方式时，sizeC/2小于S，sizeC为所述当前图像块的面积，S为预设面积阈值；或者，
    当所述划分方式为四叉树QT划分方式时，sizeC/4小于S；或者，
    当所述划分方式为扩展四叉树EQT划分方式时，sizeC/4小于S。
  9. 根据权利要求1所述的方法，其特征在于，所述判断使用所述划分方式对所述当前图像块进行划分后是否会得到满足预设条件的第一图像子块之后，还包括：
    若判断划分后不会得到所述第一图像子块，则使用所述划分方式对所述当前图像块进行划分得到多个图像子块，并分别确定所述多个图像子块的划分方式，对各所述图像子块使用对应的划分方式分别进行划分。
  10. 根据权利要求4-8中任一项所述的方法，其特征在于，所述解析所述当前图像块的码流确定第二图像子块的预测模式，包括：
    解析所述码流获取所述第二图像子块的跳过模式标识，并根据所述跳过模式标识判断所述第二图像子块的预测模式是否为所述跳过模式；
    若所述跳过模式标识指示使用所述跳过模式，则确定所述第二图像子块的预测模式为所述跳过模式。
  11. 根据权利要求10所述的方法，其特征在于，所述解析所述当前图像块的码流确定第二图像子块的预测模式，还包括：
    若所述跳过模式标识指示不使用所述跳过模式，则解析所述码流获取所述第二图像子块的直接模式标识，并根据所述直接模式标识判断所述第二图像子块的预测模式是否为所述直接模式；
    若所述直接模式标识指示使用所述直接模式，则确定所述第二图像子块的预测模式为所述直接模式。
  12. 根据权利要求11所述的方法，其特征在于，所述解析所述当前图像块的码流确定第二图像子块的预测模式，还包括：
    若所述直接模式标识指示不使用所述直接模式，则解析所述码流所述第二图像子块的预测模式标识，并根据所述预测模式标识判断所述第二图像子块的预测模式是否为所述帧内预测模式；
    若所述预测模式标识指示使用所述帧内预测模式，则确定所述第二图像子块的预测模式为所述帧内预测模式；
    若所述预测模式标识指示使用普通帧间模式，则确定所述第二图像子块的预测模式为所述普通帧间模式。
  13. 一种预测模式确定装置，其特征在于，包括：
    确定模块，用于确定当前图像块的划分方式；
    判断模块，用于判断使用所述划分方式对所述当前图像块进行划分后是否会得到满足预设条件的第一图像子块；
    划分模块，用于若判断划分后会得到所述第一图像子块，则使用所述划分方式对所述当前图像块进行划分得到多个图像子块，所述多个图像子块包括所述第一图像子块；
    预测模块，用于确定所述多个图像子块采用相同的预测模式，所述多个图像子块的预测模式同为帧内预测模式或帧间预测模式。
  14. 根据权利要求13所述的装置，其特征在于，所述的预设条件包括所述第一图像子块的面积小于或者等于设定的阈值。
  15. 根据权利要求13或14所述的装置，其特征在于，所述预测模块，具体用于解析所述当前图像块的码流确定第二图像子块的预测模式，所述第二图像子块为所述多个图像子块中第一个确定为编码单元CU的图像子块，所述第二图像子块的预测模式为所述帧内预测模式或所述帧间预测模式；根据所述第二图像子块的预测模式确定所述多个图像子块中除所述第二图像子块外的其他图像子块的预测模式，所述其他图像子块的预测模式与所述第二图像子块的预测模式同为所述帧内预测模式或所述帧间预测模式。
  16. 根据权利要求15所述的装置，其特征在于，所述帧间预测模式包括跳过模式、直接模式或普通帧间模式。
  17. 根据权利要求16所述的装置，其特征在于，所述预测模块，具体用于当所述第二图像子块的预测模式为所述帧间预测模式时，解析所述码流获取所述其他图像子块的跳过模式标识，并根据所述跳过模式标识判断所述其他图像子块的预测模式是否为所述跳过模式；若所述跳过模式标识指示使用所述跳过模式，则确定所述其他图像子块的预测模式为所述跳过模式。
  18. 根据权利要求17所述的装置，其特征在于，所述预测模块，还用于若所述跳过模式标识指示不使用所述跳过模式，则解析所述码流获取所述其他图像子块的直接模式标识，并根据所述直接模式标识判断所述其他图像子块的预测模式是否为所述直接模式；若所述直接模式标识指示使用所述直接模式，则确定所述其他图像子块的预测模式为所述直接模式；若所述直接模式标识指示不使用所述直接模式，则确定所述其他图像子块的预测模式为所述普通帧间模式。
  19. 根据权利要求16-18中任一项所述的装置，其特征在于，所述预测模块，具体用于当所述第二图像子块的预测模式为所述帧内预测模式时，解析所述码流确定所述其他图像子块的预测模式为所述帧内预测模式的其中一种。
  20. 根据权利要求13-19中任一项所述的装置，其特征在于，所述判断模块，具体用于若所述当前图像块的面积满足以下条件，则确定划分后会得到所述第一图像子块：当所述划分方式为二叉树BT划分方式时，sizeC/2小于S，sizeC为所述当前图像块的面积，S为预设面积阈值；或者，当所述划分方式为四叉树QT划分方式时，sizeC/4小于S；或者，当所述划分方式为扩展四叉树EQT划分方式时，sizeC/4小于S。
  21. 根据权利要求13所述的装置，其特征在于，所述划分模块，还用于若判断划分后不会得到所述第一图像子块，则使用所述划分方式对所述当前图像块进行划分得到多个图像子块，并分别确定所述多个图像子块的划分方式，对各所述图像子块使用对应的划分 方式分别进行划分。
  22. 根据权利要求16-20中任一项所述的装置，其特征在于，所述预测模块，具体用于解析所述码流获取所述第二图像子块的跳过模式标识，并根据所述跳过模式标识判断所述第二图像子块的预测模式是否为所述跳过模式；若所述跳过模式标识指示使用所述跳过模式，则确定所述第二图像子块的预测模式为所述跳过模式。
  23. 根据权利要求22所述的装置，其特征在于，所述预测模块，还用于若所述跳过模式标识指示不使用所述跳过模式，则解析所述码流获取所述第二图像子块的直接模式标识，并根据所述直接模式标识判断所述第二图像子块的预测模式是否为所述直接模式；若所述直接模式标识指示使用所述直接模式，则确定所述第二图像子块的预测模式为所述直接模式。
  24. 根据权利要求23所述的装置，其特征在于，所述预测模块，还用于若所述直接模式标识指示不使用所述直接模式，则解析所述码流所述第二图像子块的预测模式标识，并根据所述预测模式标识判断所述第二图像子块的预测模式是否为所述帧内预测模式；若所述预测模式标识指示使用所述帧内预测模式，则确定所述第二图像子块的预测模式为所述帧内预测模式；若所述预测模式标识指示使用普通帧间模式，则确定所述第二图像子块的预测模式为所述普通帧间模式。
  25. 一种视频编码设备，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1-12中任一项所描述的方法。
  26. 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1-12中任一项所描述的方法。
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