WO2020052304A1 - 基于仿射运动模型的运动矢量预测方法及设备 - Google Patents

基于仿射运动模型的运动矢量预测方法及设备 Download PDF

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WO2020052304A1
WO2020052304A1 PCT/CN2019/091364 CN2019091364W WO2020052304A1 WO 2020052304 A1 WO2020052304 A1 WO 2020052304A1 CN 2019091364 W CN2019091364 W CN 2019091364W WO 2020052304 A1 WO2020052304 A1 WO 2020052304A1
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block
processed
motion vector
sub
preset
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PCT/CN2019/091364
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English (en)
French (fr)
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陈焕浜
杨海涛
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华为技术有限公司
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Priority to JP2021513246A priority Critical patent/JP7279154B2/ja
Priority to SG11202102361WA priority patent/SG11202102361WA/en
Priority to BR112021004505-8A priority patent/BR112021004505A2/pt
Priority to EP19858748.7A priority patent/EP3840380A4/en
Priority to KR1020217010006A priority patent/KR102620024B1/ko
Priority to CA3112368A priority patent/CA3112368A1/en
Publication of WO2020052304A1 publication Critical patent/WO2020052304A1/zh
Priority to US17/196,642 priority patent/US11539975B2/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
    • H04N19/50—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding
    • H04N19/503—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving temporal prediction
    • H04N19/51—Motion estimation or motion compensation
    • H04N19/513—Processing of motion vectors
    • H04N19/517—Processing of motion vectors by encoding
    • H04N19/52—Processing of motion vectors by encoding by predictive encoding
    • 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
    • H04N19/50—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding
    • H04N19/503—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving temporal prediction
    • H04N19/51—Motion estimation or motion compensation
    • H04N19/527—Global motion vector estimation
    • 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
    • H04N19/105—Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for 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
    • H04N19/134—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
    • H04N19/136—Incoming video signal characteristics or properties
    • H04N19/137—Motion inside a coding unit, e.g. average field, frame or block difference
    • H04N19/139—Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
    • 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
    • H04N19/146—Data rate or code amount at the encoder output
    • H04N19/149—Data rate or code amount at the encoder output by estimating the code amount by means of a model, e.g. mathematical model or statistical model
    • 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
    • H04N19/167—Position within a video image, e.g. region of interest [ROI]
    • 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
    • H04N19/50—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding
    • H04N19/503—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving temporal prediction
    • H04N19/51—Motion estimation or motion compensation
    • H04N19/513—Processing of motion vectors
    • 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 invention relates to the field of video coding and decoding, and in particular, to a method and a device for predicting a motion vector based on an affine motion model.
  • Video encoding (video encoding and decoding) is widely used in digital video applications, such as broadcast digital TV, video transmission 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 AVC
  • ITU-T H.265 High Efficiency Video Coding
  • 3D three-dimensional
  • HEVC High Efficiency Video Coding
  • Embodiments of the present invention provide a motion vector prediction method and device based on an affine motion model, which can improve the accuracy of prediction in video encoding and decoding, and improve encoding efficiency.
  • the present invention provides a motion vector prediction method based on an affine motion model, which is described from the perspective of an encoding end or a decoding end, and includes: obtaining a spatial reference block of an image block to be processed, where the image block to be processed is For the purpose of obtaining by segmenting a video image, the spatial domain reference block is a decoded block adjacent to the spatial domain of the image block to be processed.
  • the image block to be processed is the current affine coding block
  • the spatial reference block is an adjacent affine coding block.
  • the image block to be processed is the current affine decoding block
  • the spatial reference block is an adjacent affine decoding block.
  • the image blocks to be processed may be collectively referred to as a current block, and the spatial reference blocks are collectively referred to as adjacent blocks; and then, the preset sub-block positions of two or more sub-blocks in the spatial reference block are determined, Each sub-block has a corresponding preset sub-block position.
  • the preset sub-block position is consistent with the position used when calculating the motion vector of the sub-block in the codec, that is, the sub-block of the adjacent affine decoding block uses the sub-block.
  • the motion vectors of pixels at preset positions in the block represent the motion vectors of all pixels in the sub-block; then, interpolation calculation is performed based on the motion vectors corresponding to the preset sub-block positions of the two or more sub-blocks
  • a motion vector corresponding to a preset pixel position of the image block to be processed is obtained, and the preset pixel position is a control point of the image block to be processed; then, according to the motion corresponding to the preset pixel position
  • the vector constitutes the affine motion model of the current block, and the motion vectors corresponding to the positions of multiple sub-blocks in the image block to be processed are calculated by interpolation.
  • the motion vectors corresponding to the positions of the multiple sub-blocks are respectively used to predict the motion vectors of the multiple sub-blocks.
  • the implementation of the embodiment of the present invention does not need to use the motion vector of the control point of the adjacent block, but uses the motion vector of at least two sub-blocks of the adjacent block to derive the motion vector of the control point of the current block, and then according to the control
  • the motion vector of the point is derived to obtain the motion vector of each sub-block of the current block.
  • the motion vector of the control point of the current block will not need to be stored subsequently, that is, the motion vector of the control point of the current block is only used to derive the motion vector of the sub-block of the current decoding block, and is not used to predict the motion vector of the neighboring block.
  • the solution of the present invention only needs to save the motion vectors of the sub-blocks, and uses the motion vectors of the sub-blocks for motion compensation, while solving the problem of storing the motion vectors, and avoiding that the sub-block where the control point is located is inconsistent with other sub-blocks
  • the motion vector is used for motion compensation, which improves the accuracy of prediction.
  • two sub-blocks in the spatial reference block may be determined, and a distance between two preset sub-block positions corresponding to the two sub-blocks is S, where S is a power of K , K is a non-negative integer, which is conducive to subsequent implementation of motion vector derivation, which can be implemented by means of shift, thereby reducing the complexity of implementation.
  • the preset sub-block position may be the position of the upper-left pixel point in the sub-block; or the position of the geometric center of the sub-block, or the position within the sub-block closest to the position of the geometric center.
  • the availability of candidate reference blocks of one or more preset airspace positions of the current block may be determined in a preset order, and then the first available in the preset order is obtained
  • the candidate reference block is the spatial reference block.
  • the candidate reference blocks of the preset spatial location include: adjacent image blocks located directly above, directly to the left, upper right, lower left, and upper left of the image block to be processed.
  • the availability of the candidate reference blocks is sequentially checked in the order of directly adjacent left image blocks, immediately above adjacent image blocks, upper right adjacent image blocks, lower left adjacent image blocks, and upper left adjacent image blocks.
  • Candidate reference block is
  • whether a candidate reference block is available may be determined according to the following method: when the candidate reference block and the image block to be processed are located in the same image region, and the candidate reference block obtains a motion vector based on the affine motion model When it is determined that the candidate reference block is available.
  • the positions of the plurality of preset sub-blocks of the spatial reference block include a first preset position (x4 + M / 2, y4 + N / 2) and a second preset position (x4 + M / 2 + P, y4 + N / 2), where x4 is the abscissa of the position of the upper-left pixel in the spatial reference block , Y4 is the ordinate of the position of the upper-left pixel in the spatial reference block, M is the width of the sub-block, N is the height of the sub-block, P is the power of K, K is a non-negative integer, K is less than U, and U is the number The width of the spatial reference block is described. This can be beneficial to subsequent implementation of the motion vector derivation, which can be implemented by shifting, and reduces the complexity of implementation.
  • the plurality of preset sub-block positions include a first preset position (x4 + M / 2, y4 + N / 2) and a third preset position (x4 + M / 2, y4 + N / 2 + Q), where x4 is the abscissa of the position of the upper-left pixel in the spatial reference block, and y4 is the The vertical coordinate of the position of the upper-left pixel in the spatial reference block, M is the width of the sub-block, N is the height of the sub-block, Q is the power of R, R is a non-negative integer, Q is less than V, and V is the value of the spatial reference block. height. This is conducive to subsequent motion vector derivation, which can be implemented by means of shift, and reduces the complexity of implementation.
  • the plurality of preset sub-block positions include a first preset position (x4 + M / 2, y4 + N / 2), A second preset position (x4 + M / 2 + P, y4 + N / 2) and a third preset position (x4 + M / 2, y4 + N / 2 + Q), where x4 is the airspace reference
  • x4 is the airspace reference
  • y4 is the ordinate of the position of the upper-left pixel in the spatial reference block
  • M is the width of the sub-block
  • N is the height of the sub-block
  • P is the power of K
  • Q Power of R
  • K and R are non-negative integers
  • P is less than U
  • Q is less than V
  • U is the width of the spatial domain reference block
  • V is the height of the spatial domain reference block.
  • the spatial reference block is located directly above the image block to be processed At the top left, or the top right, at least two of the sub-blocks corresponding to the plurality of preset sub-block positions are adjacent to the upper edge of the current block.
  • CTU coding tree unit
  • the straight line where the left edge of the current block is located coincides with the straight line where the left edge of the coding tree unit (CTU) where the current block is located, and the spatial reference block is located at the When directly to the left, upper left, or lower left, at least two of the sub-blocks corresponding to the plurality of preset sub-block positions are adjacent to the left edge of the current block.
  • CTU coding tree unit
  • an improved inherited control point motion vector prediction method is used to determine candidate control point motion vectors for the current block, that is, using adjacent affine coding blocks (or adjacent affine decoding Block) from the motion vectors of at least two sub-blocks.
  • the motion vector of the preset pixel position of the current block is obtained by interpolation calculation.
  • the preset pixel position is the control point of the current block. For example, if the affine motion model of the current block Is a 4-parameter affine motion model, then the control points of the current block can be the upper left pixel point and the upper right pixel point in the sub-block. If the affine motion model of the current block is a 6-parameter affine motion model, the control points of the current block may be the upper left pixel point, the upper right pixel point, and the lower left pixel point in the sub-block, and so on.
  • the control point of the current block may include the position of the pixel point in the upper left corner of the image block to be processed. Said at least two of the position of the pixel point in the upper right corner in the image block to be processed and the position of the pixel point in the bottom left corner in the image block to be processed, and said interpolation is calculated according to the motion vector corresponding to the preset subblock position
  • the motion vector corresponding to the preset pixel position of the image block to be processed includes calculating the motion vector corresponding to the preset pixel position of the image block to be processed according to the following formula:
  • vx 0 is the horizontal component of the motion vector corresponding to the position of the upper left pixel point in the image block to be processed
  • vy 0 is the vertical component of the motion vector corresponding to the position of the pixel point in the upper left corner in the image block to be processed
  • vx 1 is the horizontal component of the motion vector corresponding to the pixel position of the upper right corner in the image block to be processed
  • vy 1 is the vertical component of the motion vector corresponding to the pixel position of the upper right corner in the image block to be processed
  • vx 2 is The horizontal component of the motion vector corresponding to the position of the bottom left pixel point in the image block to be processed is described
  • vy 2 is the vertical component of the motion vector corresponding to the position of the bottom left pixel point in the image block to be processed
  • vx 4 is the first The horizontal component of the motion vector corresponding to the preset position
  • vy 4 is the vertical component of the motion vector corresponding to the first preset position
  • vx 5
  • the control point of the current block may include the position of the pixel point in the upper left corner of the image block to be processed.
  • the position of the pixel point in the upper right corner of the image block to be processed and the position of the pixel point in the lower left corner of the image block to be processed are calculated, and the interpolation of the image block to be processed is performed according to the motion vector corresponding to the preset subblock position.
  • a motion vector corresponding to a pixel position includes calculating a motion vector corresponding to a preset pixel position of the image block to be processed according to the following formula:
  • vx 0 is the horizontal component of the motion vector corresponding to the position of the upper left pixel point in the image block to be processed
  • vy 0 is the vertical component of the motion vector corresponding to the position of the pixel point in the upper left corner in the image block to be processed
  • vx 1 is the horizontal component of the motion vector corresponding to the pixel position of the upper right corner in the image block to be processed
  • vy 1 is the vertical component of the motion vector corresponding to the pixel position of the upper right corner in the image block to be processed
  • vx 2 is The horizontal component of the motion vector corresponding to the position of the bottom left pixel point in the image block to be processed is described
  • vy 2 is the vertical component of the motion vector corresponding to the position of the bottom left pixel point in the image block to be processed
  • vx 4 is the first The horizontal component of the motion vector corresponding to the preset position
  • vy 4 is the vertical component of the motion vector corresponding to the first preset position
  • vx 5
  • a sub-block can also be equivalent to a motion compensation unit, and the width and height of the sub-block are smaller than the width and height of the current block
  • the motion information of pixels in a preset position in the motion compensation unit is used to represent the motion information of all pixels in the motion compensation unit.
  • the preset position pixels can be the center point of the motion compensation unit (M / 2, N / 2), the upper left pixel (0, 0), and the upper right pixel (M-1,0 ), Or pixels at other locations.
  • the motion vector value of each sub-block in the current block can be obtained, and subsequent motion compensation can be performed according to the motion vector value of the sub-block to obtain the sub-block.
  • subsequent motion compensation can be performed according to the motion vector value of the sub-block to obtain the sub-block.
  • the preset pixel position includes the position of the upper left pixel point in the image block to be processed and The position of the pixel point in the upper right corner of the image block to be processed is calculated by interpolation based on the motion vector corresponding to the preset pixel point position, and the motion vectors corresponding to the positions of multiple sub-blocks in the image block to be processed include: The formula calculates the motion vectors corresponding to the positions of multiple sub-blocks in the image block to be processed:
  • vx is the horizontal component of a corresponding motion vector at (x, y) of the plurality of sub-block positions
  • vy is at (x , y) A vertical component of a corresponding motion vector.
  • the interpolation calculates the target value based on a motion vector corresponding to the preset pixel point position.
  • Processing the motion vectors corresponding to the positions of multiple sub-blocks in the image block includes calculating the motion vectors corresponding to the positions of multiple sub-blocks in the image block to be processed according to the following formula:
  • W is the width of the image block to be processed
  • H is the height of the image block to be processed
  • vx is the horizontal component of a corresponding motion vector at (x, y) of the plurality of sub-block positions
  • vy Is the vertical component of a corresponding motion vector at (x, y) of the plurality of sub-block positions.
  • an embodiment of the present invention provides a device, the device includes: a reference block acquisition module for acquiring an airspace reference block of an image block to be processed in the video data; a subblock determination module for determining A plurality of preset sub-block positions in the spatial reference block; a first calculation module configured to interpolate and calculate a position corresponding to a preset pixel position of the image block to be processed according to a motion vector corresponding to the preset sub-block position; A motion vector; a second calculation module, configured to interpolate and calculate a motion vector corresponding to a plurality of sub-block positions in the image block to be processed according to the motion vector corresponding to the preset pixel point position.
  • each module of the device may be used to implement the method described in the first aspect.
  • an embodiment of the present invention provides a device for decoding a video, and the device includes:
  • Memory for storing video data in the form of a stream
  • the decoder is specifically configured to: determine the availability of candidate reference blocks of one or more preset spatial domain positions of the image blocks to be processed according to a preset order; Let the first available candidate reference block in the sequence be used as the airspace reference block.
  • the candidate reference block when the candidate reference block is located in the same image region as the image block to be processed, and the candidate reference block obtains a motion vector based on the affine motion model, determine The candidate reference blocks are available.
  • the candidate reference blocks of the preset spatial location include: adjacent images located directly above the image block to be processed, directly to the left, upper right, lower left, and upper left Piece;
  • the decoder is specifically configured to: sequentially check the availability of the candidate reference blocks in the order of directly adjacent image blocks, directly adjacent image blocks, upper right adjacent image blocks, lower left adjacent image blocks, and upper left adjacent image blocks in order.
  • the first available candidate reference block is specifically configured to: sequentially check the availability of the candidate reference blocks in the order of directly adjacent image blocks, directly adjacent image blocks, upper right adjacent image blocks, lower left adjacent image blocks, and upper left adjacent image blocks in order.
  • the position of the sub-block includes: a position of an upper-left pixel point in the sub-block; or a position of a geometric center of the sub-block, or a position of a pixel point closest to the geometric center in the sub-block position.
  • a distance between two preset sub-block positions in the plurality of preset sub-block positions is S, S is a power of K, and K is a non-negative integer .
  • the affine motion model is a 4-parameter affine motion model
  • the plurality of preset sub-block positions include a first preset position (x4 + M / 2, y4 + N / 2) and a second preset position (x4 + M / 2 + P, y4 + N / 2), where x4 is the abscissa of the position of the upper-left pixel in the spatial reference block, and y4 is the spatial reference
  • M is the width of the sub-block
  • N is the height of the sub-block
  • P is the power of K
  • 2 is a non-negative integer
  • K is less than U
  • U is the width of the spatial reference block.
  • the affine motion model is a 4-parameter affine motion model
  • the plurality of preset sub-block positions include a first preset position (x4 + M / 2, y4 + N / 2) and a third preset position (x4 + M / 2, y4 + N / 2 + Q), where x4 is the abscissa of the position of the upper-left pixel in the spatial reference block, and y4 is the spatial reference
  • M is the width of the sub-block
  • N is the height of the sub-block
  • Q is the power of R
  • R is a non-negative integer
  • Q is less than V
  • V is the height of the spatial reference block.
  • the affine motion model is a 4-parameter affine motion model
  • the preset pixel position includes the position of the upper left pixel point in the image block to be processed
  • the decoder specifically For calculating a motion vector corresponding to a preset pixel position of the image block to be processed according to the following formula:
  • vx 0 is the horizontal component of the motion vector corresponding to the position of the upper left pixel point in the image block to be processed
  • vy 0 is the vertical component of the motion vector corresponding to the position of the pixel point in the upper left corner in the image block to be processed
  • vx 1 is the horizontal component of the motion vector corresponding to the pixel position of the upper right corner in the image block to be processed
  • vy 1 is the vertical component of the motion vector corresponding to the pixel position of the upper right corner in the image block to be processed
  • vx 2 is The horizontal component of the motion vector corresponding to the position of the bottom left pixel point in the image block to be processed is described
  • vy 2 is the vertical component of the motion vector corresponding to the position of the bottom left pixel point in the image block to be processed
  • vx 4 is the first The horizontal component of the motion vector corresponding to the preset position
  • vy 4 is the vertical component of the motion vector corresponding to the first preset position
  • vx 5
  • the affine motion model is a 4-parameter affine motion model
  • the preset pixel position includes an upper left pixel position in the image block to be processed and the target position The position of the pixel point in the upper right corner of the image block is processed
  • the decoder is specifically configured to calculate the motion vectors corresponding to the positions of multiple sub-blocks in the image block to be processed according to the following formula:
  • vx is the horizontal component of a corresponding motion vector at (x, y) of the plurality of sub-block positions
  • vy is at (x , y) A vertical component of a corresponding motion vector.
  • the affine motion model is a 6-parameter affine motion model
  • the positions of the plurality of preset sub-blocks include a first preset position (x4 + M / 2, y4 + N / 2), the second preset position (x4 + M / 2 + P, y4 + N / 2) and the third preset position (x4 + M / 2, y4 + N / 2 + Q), where x4 Is the abscissa of the position of the upper-left pixel in the spatial reference block, y4 is the ordinate of the position of the upper-left pixel in the spatial reference block, M is the width of the sub-block, N is the height of the sub-block, and P is the power of K , Q is the power of R, K and R are non-negative integers, P is less than U, Q is less than V, U is the width of the spatial domain reference block, and V is the height of the spatial domain reference block.
  • the affine motion model is a 6-parameter affine motion model
  • the preset pixel position includes a position of an upper left pixel point in the image block to be processed.
  • the position of the pixel point in the upper right corner of the image block and the position of the pixel point in the lower left corner of the image block to be processed are specifically configured to calculate a motion vector corresponding to the preset pixel position of the image block to be processed according to the following formula:
  • vx 0 is the horizontal component of the motion vector corresponding to the position of the upper left pixel point in the image block to be processed
  • vy 0 is the vertical component of the motion vector corresponding to the position of the pixel point in the upper left corner in the image block to be processed
  • vx 1 is the horizontal component of the motion vector corresponding to the pixel position of the upper right corner in the image block to be processed
  • vy 1 is the vertical component of the motion vector corresponding to the pixel position of the upper right corner in the image block to be processed
  • vx 2 is The horizontal component of the motion vector corresponding to the position of the bottom left pixel point in the image block to be processed is described
  • vy 2 is the vertical component of the motion vector corresponding to the position of the bottom left pixel point in the image block to be processed
  • vx 4 is the first The horizontal component of the motion vector corresponding to the preset position
  • vy 4 is the vertical component of the motion vector corresponding to the first preset position
  • vx 5
  • the affine motion model is a 6-parameter affine motion model
  • the decoder is specifically configured to calculate a position corresponding to multiple sub-blocks in the image block to be processed according to the following formula: Motion vector:
  • W is the width of the image block to be processed
  • H is the height of the image block to be processed
  • vx is the horizontal component of a corresponding motion vector at (x, y) of the plurality of sub-block positions
  • vy Is the vertical component of a corresponding motion vector at (x, y) of the plurality of sub-block positions.
  • the straight line where the upper edge of the image block to be processed lies and the straight line where the upper edge of the coding tree unit CTU where the image block to be processed coincides and the airspace
  • at least two of the sub-blocks corresponding to the plurality of preset sub-block positions are adjacent to the upper edge of the image block to be processed .
  • the method described in the first aspect of the invention can be performed by a device according to the third aspect of the invention.
  • Other features and implementations of the method of the first aspect of the invention directly depend on the functionality of the device according to the third aspect of the invention and its different implementations.
  • an embodiment of the present invention provides a device for encoding a video, where the device includes:
  • Memory for storing video data in the form of a stream
  • the method of the first aspect of the invention can be performed by a device described in accordance with the fourth aspect of the invention.
  • Other features and implementations of the method of the first aspect of the invention directly depend on the functionality of the device according to the fourth aspect of the invention and its different implementations.
  • the present invention relates to a device for decoding a video stream, including a processor and a memory.
  • the memory stores instructions that cause the processor to perform the method according to the first aspect.
  • an embodiment of the present invention provides a device for decoding a video stream, including a processor and a memory.
  • the memory stores instructions that cause the processor to perform the method according to the first aspect.
  • an embodiment of the present invention provides an apparatus for encoding a video stream, including a processor and a memory.
  • the memory stores instructions that cause the processor to perform the method according to the first aspect.
  • an embodiment of the present invention provides a computer-readable storage medium having stored thereon instructions that, when executed, cause one or more processors to encode video data.
  • the instructions cause the one or more processors to perform a method according to any possible embodiment of the first aspect.
  • an embodiment of the present invention provides a computer program including a program code that, when run on a computer, executes a method according to any possible embodiment of the first aspect.
  • the embodiment of the present invention adopts an improved inherited control point motion vector prediction method.
  • the improved inherited control point motion vector prediction method does not need to use the motion vectors of control points of adjacent blocks, but uses adjacent blocks.
  • the motion vectors of at least two sub-blocks are used to derive the motion vectors of the control points of the current block, and then the motion vectors of each sub-block of the current block are derived based on the motion vectors of the control points, and prediction of the current block is achieved through motion compensation.
  • the motion vector of the control point of the current block does not need to be stored subsequently, that is, the motion vector of the control point of the current block is only used to derive the motion vector of the sub-block of the current decoding block, and is not used to predict the motion vector of the neighboring block. Therefore, the solution of the present invention only needs to save the motion vectors of the sub-blocks, and uses the motion vectors of the sub-blocks for motion compensation, while solving the problem of storing the motion vectors, and avoiding that the sub-block where the control point is located is inconsistent with other sub-blocks
  • the motion vector is used for motion compensation, which improves the accuracy of prediction.
  • FIG. 1A is a block diagram of an example of a video encoding and decoding system 10 for implementing an embodiment of the present invention
  • 1B is a block diagram of an example of a video decoding system 40 for implementing an embodiment of the present invention
  • FIG. 2 is a block diagram of an example structure of an encoder 20 for implementing an embodiment of the present invention
  • FIG. 3 is a block diagram of an example structure of a decoder 30 for implementing an embodiment of the present invention
  • FIG. 4 is a block diagram of an example of a video decoding device 400 for implementing an embodiment of the present invention
  • FIG. 5 is a block diagram of another example of an encoding device or a decoding device for implementing an embodiment of the present invention
  • FIG. 6 is a schematic diagram of a scenario operation on the current block
  • FIG. 7 is a schematic diagram of another scenario operation on the current block
  • FIG. 8 is a schematic diagram of another scenario operation on the current block
  • FIG. 9 is a schematic diagram of another scenario operation on the current block.
  • FIG. 10 is a schematic diagram of another scenario operation on the current block
  • FIG. 11 is a flowchart of a motion vector prediction method based on an affine motion model according to an embodiment of the present invention
  • FIG. 12 is a flowchart of another motion vector prediction method based on an affine motion model according to an embodiment of the present invention.
  • FIG. 13 is a schematic diagram of another example operation on the current block
  • FIG. 14 is a flowchart of another motion vector prediction method based on an affine motion model according to an embodiment of the present invention.
  • FIG. 15 is a structural block diagram of a device for implementing an embodiment of the present invention.
  • the corresponding device may include one or more units such as functional units to perform the described one or more method steps (e.g., one unit performs one or more steps Or multiple units, each of which performs one or more of the 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 (e.g., a step performs one or more units Functionality, or multiple steps, where each 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.
  • Video coding generally refers to processing a sequence of pictures that form a video or a video sequence.
  • picture In the field of video coding, the terms “picture”, “frame” or “image” can be used as synonyms.
  • Video encoding as used herein means video encoding or video decoding.
  • Video encoding is performed on the source side and typically involves processing (e.g., 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 video picture “encoding” involved in the embodiment should be understood as the “encoding” or “decoding” of the video sequence.
  • the combination of the encoding part and the decoding part is also called codec (encoding and decoding).
  • the video sequence includes a series of pictures.
  • the pictures are further divided into slices, and the slices are divided into blocks.
  • Video coding is encoded in blocks.
  • the concept of blocks is further expanded.
  • MB macroblock
  • the macroblock can be further divided into multiple prediction blocks (partitions) that can be used for predictive coding.
  • HEVC high-performance video coding
  • basic concepts such as coding unit (CU), prediction unit (PU), and transformation unit (TU) are used. Functionally, Divided a variety of block units, and used a new tree-based description.
  • a CU can be divided into smaller CUs according to a quadtree, and smaller CUs can be further divided to form a quadtree structure.
  • a CU is a basic unit for dividing and encoding a coded image.
  • the PU and TU have similar tree structures.
  • the PU can correspond to the prediction block, which is the basic unit of prediction coding.
  • the CU is further divided into multiple PUs according to the division mode.
  • TU can correspond to a transform block and is a basic unit for transforming prediction residuals. However, no matter CU, PU or TU, they all belong to the concept of block (or image block).
  • a CTU is split into multiple CUs by using a quad-tree 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 a picture region.
  • 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.
  • a CU may be partitioned into a transform unit (TU) according to other quad-tree structures similar to a coding tree for a CU.
  • quad-tree and binary-tree (QTBT) split frames are used to split coded blocks.
  • the CU may be a square or rectangular shape.
  • the image block to be encoded in the currently encoded image may be referred to as the current block, for example, in encoding, it means the block currently being encoded; in decoding, it means the block currently being decoded.
  • the decoded image block in the reference image used to predict the current block is referred to as a reference block, that is, 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 a prediction signal for the current block may be a prediction block, where the prediction signal represents a pixel value or a sampling value or a sampling signal within the prediction block. For example, after traversing multiple reference blocks, the best reference block is found. This best reference block will provide 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 there is 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, and the decoder side cannot completely reconstruct the video picture, that is, the quality of the reconstructed video picture is compared to the original video picture The quality is lower or worse.
  • Each picture of a video sequence is usually partitioned into a set of non-overlapping blocks, usually encoded at the block level.
  • the encoder side usually processes at the block (video block) level, that is, encodes the video.
  • 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 predictions (such as intra prediction and inter prediction) and / or reconstruction for processing, that is, encoding subsequent blocks.
  • Fig. 1A exemplarily shows a schematic block diagram of a video encoding and decoding system 10 applied to an embodiment of the present invention.
  • 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. 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 thus, the destination device 14 may be referred to as a video decoding device.
  • the source device 12 and the destination device 14 may include one or more processors and a memory coupled to the one or more processors.
  • the memory may include, but is not limited to, RAM, ROM, EEPROM, flash memory, or any other media that can be used to store the desired program code in the form of instructions or data structures accessible by a computer, as described herein.
  • the source device 12 and the destination device 14 may include various devices including desktop computers, mobile computing devices, notebook (e.g., 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, on-board computers, wireless communication devices, or the like.
  • FIG. 1A illustrates the source device 12 and the destination device 14 as separate devices
  • the device embodiment may also include the source device 12 and the destination device 14 or both of the functionality, that is, the source device 12 or corresponding And the functionality of the destination device 14 or equivalent.
  • the same hardware and / or software, 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 source device 12 and the destination device 14 may be communicatively connected through a link 13, and the destination device 14 may receive encoded video data from the source device 12 via the link 13.
  • the link 13 may include one or more media or devices capable of moving the encoded video data from the source device 12 to the destination device 14.
  • the link 13 may include one or more communication media enabling the source device 12 to directly transmit the encoded video data to the destination device 14 in real time.
  • the source device 12 may modulate the encoded video data according to a communication standard, such as 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 the source device 12 to the 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 preprocessor 18, and the communication interface 22 may be hardware components in the source device 12, or software programs in the source device 12. They are described as follows:
  • Picture source 16 which may include or may be any kind of picture capture device, for example to capture real-world pictures, and / or any kind of pictures or comments (for screen content encoding, some text on the screen is also considered to be encoded Picture or image) generating device, for example, a computer graphics processor for generating computer animated pictures, or for obtaining and / or providing real world pictures, computer animated pictures (for example, screen content, virtual reality, (VR) pictures), and / or any combination thereof (e.g., augmented reality pictures).
  • the picture source 16 may be a camera for capturing pictures or a memory for storing pictures, and 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 local or, 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 for receiving pictures from an external video source.
  • the external video source is, for example, an external picture capture device, such as a camera, external memory, or an external picture generation device.
  • 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 of the array or picture in the horizontal and vertical directions (or axes) defines the size and / or resolution of the picture.
  • three color components are usually used, that is, a picture can be represented as or contain three sampling arrays.
  • the picture includes corresponding red, green, and blue sampling arrays.
  • each pixel is usually represented in luma / chroma format or color space.
  • a picture in YUV format includes the luminance component indicated by Y (sometimes it can also be indicated by L) and the two indicated by U and V Chroma components.
  • the luma component Y represents the brightness or gray level intensity (for example, they are the same in a gray scale picture), and the two chroma components U and V represent the chroma or color information components.
  • a picture in the YUV format includes a luminance sample array of luminance sample values (Y) and two chrominance sample arrays of chrominance values (U and V).
  • Pictures in RGB format can be converted or converted to YUV format, and vice versa. This process is also called color conversion or conversion. If the picture is black and white, the picture can include only an array of luminance samples.
  • a 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 a pre-processed picture 19 or pre-processed picture data 19.
  • the pre-processing performed by the picture pre-processor 18 may include retouching, color format conversion (eg, conversion from RGB format to YUV format), color correction, or denoising.
  • An encoder 20 (also referred to as a video encoder 20) is configured to receive the preprocessed picture data 19, and use a related prediction mode (such as the prediction mode in various embodiments herein) to process the preprocessed picture data 19, 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 configured to execute various embodiments described later to implement the application of the chroma block prediction method described in the present invention 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) for storage or direct reconstruction through the link 13.
  • 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.
  • the destination device 14 may further include a communication interface 28, a picture post-processor 32, and a display device 34. They are described as follows:
  • the communication interface 28 may be used to receive the encoded picture data 21 from the source device 12 or any other source, such as a storage device, and the storage device is, for example, 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, any
  • the type of network is, for example, a wired or wireless network or any combination thereof, or any type of private and public network, or any combination thereof.
  • the communication interface 28 may be used, for example, to decapsulate the data packets 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 related to data transmission.
  • a decoder 30 (or called a decoder 30) for receiving the encoded picture data 21 and providing the decoded picture data 31 or the decoded picture 31 (hereinafter, the description of the decoder 30 based on FIG. 3 or FIG. 4 or FIG. 5 will be further described). Structural details).
  • the decoder 30 may be configured to execute various embodiments described later to implement the application of the chroma block prediction method described in the present invention on the decoding side.
  • the picture post-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 picture post-processor 32 may include: color format conversion (for example, conversion from YUV format to RGB format), color correction, retouching, or resampling, or any other processing. 33 transmitting to a display device 34.
  • a display device 34 is configured to receive post-processed picture data 33 to display a picture to, for example, a user or a viewer.
  • the display device 34 may be or may include any kind of display for presenting a reconstructed picture, such as 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 (DLP) or any other display of any kind.
  • FIG. 1A illustrates the source device 12 and the destination device 14 as separate devices
  • the device embodiment may also include both the source device 12 and the destination device 14 or the functionality of both, that is, the source device 12 or Corresponding functionality and destination device 14 or corresponding functionality.
  • the same hardware and / or software, or separate hardware and / or software, or any combination thereof may be used to implement the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality .
  • Source device 12 and destination device 14 may include any of a variety of devices, including any type of handheld or stationary device, such as a notebook or laptop computer, mobile phone, smartphone, tablet or tablet computer, video camera, desktop Computer, set-top box, television, camera, in-vehicle device, display device, digital media player, video game console, video streaming device (e.g. content service server or content distribution server), broadcast receiver device, broadcast transmitter device Etc. and can not use or use any kind of operating system.
  • handheld or stationary device such as a notebook or laptop computer, mobile phone, smartphone, tablet or tablet computer, video camera, desktop Computer, set-top box, television, camera, in-vehicle device, display device, digital media player, video game console, video streaming device (e.g. content service server or content distribution server), broadcast receiver device, broadcast transmitter device Etc. and can not use or use any kind of operating system.
  • Both the encoder 20 and the decoder 30 may be implemented as any of various suitable circuits, for example, one or more microprocessors, digital signal processors (DSPs), application-specific integrated circuits (application-specific integrated circuits) circuit (ASIC), field-programmable gate array (FPGA), discrete logic, hardware, or any combination thereof.
  • DSPs digital signal processors
  • ASIC application-specific integrated circuits
  • FPGA field-programmable gate array
  • the device may store the software's instructions 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.) can be considered as one or more processors.
  • the video encoding and decoding system 10 shown in FIG. 1A is merely an example, and the techniques of the present application may be applicable to a video encoding setting that does not necessarily include any data communication between encoding and decoding devices (e.g., video encoding or video decoding).
  • data may be retrieved from local storage, streamed over a network, and the like.
  • the video encoding device may encode the data and store the data to a 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 data.
  • FIG. 1B is an explanatory diagram of an example of a video decoding 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 invention.
  • the video decoding system 40 may include an imaging device 41, an encoder 20, a decoder 30 (and / or a video encoder / decoder implemented by the logic circuit 47 of the processing unit 46), and an antenna 42 , One or more processors 43, one or more memories 44, and / or a display device 45.
  • the imaging device 41, antenna 42, processing unit 46, logic circuit 47, encoder 20, decoder 30, processor 43, memory 44, and / or display device 45 can communicate with each other.
  • the video decoding system 40 is shown with an encoder 20 and a decoder 30, in different examples, the video decoding system 40 may include only the encoder 20 or only the decoder 30.
  • antenna 42 may be used to transmit or receive an encoded bit stream of video data.
  • the display device 45 may be used to present video data.
  • the logic circuit 47 may be implemented by the processing unit 46.
  • the processing unit 46 may include application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, and the like.
  • the video decoding system 40 may also include an optional processor 43.
  • the optional processor 43 may similarly include application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, and the like.
  • the logic circuit 47 may be implemented by hardware, such as dedicated hardware for video encoding, and the processor 43 may be implemented by general software, operating system, and the like.
  • the memory 44 may be any type of memory, such as volatile memory (e.g., Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), etc.) or non-volatile memory Memory (for example, flash memory, etc.).
  • volatile memory e.g., Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), etc.
  • non-volatile memory Memory for example, flash memory, etc.
  • the memory 44 may be implemented by a cache memory.
  • the logic circuit 47 may access the memory 44 (eg, for implementing an image buffer).
  • the logic circuit 47 and / or the processing unit 46 may include a memory (eg, a cache, etc.) for implementing an image buffer or the like.
  • the encoder 20 implemented by a logic circuit may include an image buffer (eg, implemented by the processing unit 46 or the memory 44) and a graphics processing unit (eg, implemented by the processing unit 46).
  • the graphics processing unit may be communicatively coupled to the image buffer.
  • the graphics processing unit may include an encoder 20 implemented by a logic circuit 47 to implement 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 various operations discussed herein.
  • decoder 30 may be implemented in a similar manner through logic circuit 47 to implement the various modules discussed with reference to decoder 30 of FIG. 3 and / or any other decoder system or subsystem described herein.
  • the decoder 30 implemented by a logic circuit may include an image buffer (implemented by the processing unit 2820 or the memory 44) and a graphics processing unit (eg, implemented by the processing unit 46).
  • the graphics processing unit may be communicatively coupled to the image buffer.
  • the graphics processing unit may include a decoder 30 implemented by a logic circuit 47 to implement the 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 bit stream of video data.
  • the encoded bitstream may contain data, indicators, index values, mode selection data, and the like related to encoded video frames discussed herein, such as data related to coded segmentation (e.g., transform coefficients or quantized transform coefficients) , (As discussed) optional indicators, and / or data defining code partitions).
  • 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 related video data accordingly.
  • the encoder 20 may entropy encode syntax elements into an encoded video bitstream.
  • the decoder 30 may parse such syntax elements and decode the relevant video data accordingly.
  • the motion vector prediction method based on the affine motion model described in the embodiment of the present invention is mainly used in the inter prediction process. This process exists in both the encoder 20 and the decoder 30.
  • the encoder in the embodiment of the present invention 20 and decoder 30 may be codecs corresponding to video standard protocols such as H.263, H.264, HEVV, MPEG-2, MPEG-4, VP8, VP9 or the next-generation video standard protocols (such as H.266, etc.) decoder.
  • the encoder 20 includes a residual calculation unit 204, a transformation processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transformation processing unit 212, a reconstruction unit 214, a buffer 216, and a loop filter.
  • 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 according to a hybrid video codec.
  • the residual calculation unit 204, the transformation 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 the inverse quantization unit 210, the inverse transformation processing unit 212,
  • the constructing 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, wherein the backward signal path of the encoder corresponds to To the decoder's signal path (see decoder 30 in Figure 3).
  • the encoder 20 receives the picture 201 or the image block 203 of the picture 201 through, for example, the input 202, for example, a picture in a picture sequence forming a video or a video sequence.
  • the image block 203 can also be called the current picture block or the picture block to be encoded
  • the picture 201 can be called the current picture or the picture to be encoded (especially when the current picture is distinguished from other pictures in video encoding, other pictures such as the same video sequence (Ie previously encoded and / or decoded pictures in the video sequence of the current picture).
  • the embodiment of the encoder 20 may include a dividing unit (not shown in FIG. 2) for dividing the picture 201 into a plurality of blocks, such as an image block 203, and generally divides into a plurality of non-overlapping blocks.
  • the segmentation unit can be used to use the same block size and corresponding raster to define the block size for all pictures in the video sequence, or to change the block size between pictures or subsets or groups of pictures, and split each picture into Corresponding block.
  • the prediction processing unit 260 of the encoder 20 may be used to perform any combination of the segmentation techniques described above.
  • image block 203 is 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, a luminance array in the case of a black and white picture 201) or three sampling arrays (for example, one luminance array and two chroma arrays in the case of a color picture) Any other number and / or category of arrays 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 a picture 201 block by block, for example, performing encoding and prediction on each image block 203.
  • the residual calculation unit 204 is configured to calculate the residual block 205 based on the picture image block 203 and the prediction block 265 (the other details of the prediction block 265 are provided below). For example, the sample value of the picture image block 203 is subtracted by sample by pixel (pixel by pixel). The sample values of the prediction block 265 are de-predicted to obtain the residual block 205 in the sample domain.
  • the transform processing unit 206 is configured 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.
  • a transform such as discrete cosine transform (DCT) or discrete sine transform (DST)
  • DCT discrete cosine transform
  • DST discrete sine transform
  • the transform coefficient 207 may also be referred to as a transform residual coefficient, and represents a residual block 205 in a transform domain.
  • the transform processing unit 206 may be used to apply an integer approximation of DCT / DST, such as the transform specified for HEVC / H.265. Compared to an orthogonal DCT transform, this integer approximation is usually scaled by a factor. To maintain the norm of the residual blocks processed by the forward and inverse transforms, 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 shift operations, the bit depth of the transform coefficients, the trade-off between accuracy, and implementation cost.
  • a specific scaling factor is specified on the decoder 30 side by, for example, the inverse transform processing unit 212 (and on the encoder 20 side by, for example, the inverse transform processing unit 212 as the corresponding inverse transform), and accordingly, the The 20 side specifies a corresponding scaling factor for the positive transformation through the transformation processing unit 206.
  • the quantization unit 208 is used to quantize the transform coefficients 207, for example, by applying scalar quantization or vector quantization to obtain the quantized transform coefficients 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 may 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 the quantization parameter (QP). For scalar quantization, for example, different scales can be applied to achieve finer or coarser quantization.
  • a smaller quantization step size corresponds to a finer quantization, while a larger quantization step size corresponds to a coarser quantization.
  • An appropriate 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)
  • Quantization may include division by a quantization step size and corresponding quantization or inverse quantization performed, for example, by inverse quantization 210, or may include multiplication by a 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 using a fixed-point approximation using an equation containing division based on the quantization parameter. Additional scaling factors may 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 the fixed-point approximation of the equation for the quantization step size and quantization parameter.
  • inverse transform and inverse quantization scales can be combined.
  • a custom quantization table can be used and signaled from the encoder to the decoder in, for example, a bitstream. Quantization is a lossy operation, where the larger the quantization step, the greater the loss.
  • the inverse quantization unit 210 is used to apply the inverse quantization of the quantization unit 208 on the quantized coefficients to obtain the inverse quantized coefficients 211. For example, based on or using the same quantization step size as the quantization unit 208, the quantization scheme applied by the quantization unit 208 is applied. Inverse quantization scheme.
  • the dequantized coefficient 211 may also be referred to as a dequantized residual coefficient 211, which corresponds to the transform coefficient 207, although the loss due to quantization is usually different from the transform coefficient.
  • the inverse transform processing unit 212 is used to apply an 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.
  • DCT inverse discrete cosine transform
  • DST inverse discrete sine transform
  • the inverse transform block 213 may also be referred to as an inverse transform inverse quantized block 213 or an inverse transform residual block 213.
  • the reconstruction unit 214 (for example, the summer 214) is used to add the inverse transform block 213 (that is, the reconstructed residual block 213) to the prediction block 265 to obtain the reconstructed block 215 in the sample domain.
  • the sample values of the reconstructed residual block 213 are added to the sample values of the prediction block 265.
  • 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 example, for intra prediction.
  • the encoder may be used to use any unfiltered reconstructed block and / or corresponding sample values stored in the buffer unit 216 for any category of estimation and / or prediction, such as intra-frame prediction.
  • an embodiment of the encoder 20 may be configured such that the buffer unit 216 is used not only for storing 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, to make the buffer unit 216 and the decoded picture buffer unit 230 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 the input or basis for the intra prediction 254.
  • the loop filter unit 220 (or simply "loop filter” 220) is configured 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 a deblocking filter, a sample-adaptive offset (SAO) filter, or other filters, such as a bilateral filter, Adaptive loop filters (adaptive loop filters, ALF), or sharpening or smoothing filters, or cooperative filters.
  • 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 a filtered reconstructed block 221.
  • the decoded picture buffer 230 may store the reconstructed encoded block after the loop filter unit 220 performs a filtering operation on the reconstructed encoded block.
  • An embodiment of the encoder 20 may be used to output loop filter parameters (e.g., sample adaptive offset information), for example, directly output or by the entropy coding unit 270 or any other
  • the entropy coding unit outputs after entropy coding, for example, so that the decoder 30 can receive and apply the same loop filter parameters for decoding.
  • the decoded picture buffer (DPB) 230 may be a reference picture memory that stores 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 (DRAM) (including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), and resistive RAM (resistive RAM, RRAM)) or other types of memory devices.
  • DRAM dynamic random access
  • 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 previously reconstructed pictures, such as the previously reconstructed and filtered block 221, and may provide a complete previous Reconstruction is the decoded picture (and corresponding reference blocks and samples) and / or part of the reconstructed current picture (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.
  • a prediction processing unit 260 also referred to as a block prediction processing unit 260, is used to receive or obtain image block 203 (current image block 203 of current picture 201) and reconstructed picture data, such as the same (current) picture from buffer 216 Reference samples and / or reference picture data 231 of one or more previously decoded pictures from the decoded picture buffer 230, and for processing such data for prediction, providing a block that can be The prediction block 265 of the intra prediction block 255.
  • the mode selection unit 262 may be used to select a prediction mode (such as an intra or inter prediction mode) and / or a 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 such as an intra or inter prediction mode
  • a 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 (e.g., selected from those prediction modes supported by the prediction processing unit 260) that provides the best match or minimum residual (minimum residual means Better compression in transmission or storage), or provide minimal signaling overhead (minimum signaling overhead means better compression in transmission or storage), or consider or balance both.
  • 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 the minimum code rate distortion optimization, or to select a prediction mode whose related code rate distortion meets at least 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 a set of (predetermined) prediction modes.
  • the prediction mode set may include, for example, an intra prediction mode and / or an inter prediction mode.
  • the set of intra prediction modes may include 35 different intra prediction modes, for example, non-directional modes such as DC (or average) mode and planar mode, or directional modes as defined in H.265, or may include 67 Different intra prediction modes, such as non-directional modes such as DC (or mean) mode and planar mode, or directional modes as defined in the developing H.266.
  • the set of inter prediction modes depends on the available reference pictures (i.e., for example, the aforementioned at least partially decoded pictures stored in DBP 230) and other inter prediction parameters, such as whether to use the entire reference picture or just use Part of a reference picture, such as 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, an Advanced Motion Vector (AMVP) mode and a merge mode.
  • the inter prediction mode set may include an improved AMVP mode based on control points and an improved merge mode based on control points in the embodiment of the present invention.
  • the intra prediction unit 254 may be used to perform any combination of the inter prediction techniques described below.
  • embodiments of the present invention may also apply a skip mode and / or a direct mode.
  • the prediction processing unit 260 may be further configured to divide the image block 203 into smaller block partitions or sub-blocks, for example, iteratively uses quad-tree (QT) segmentation, binary-tree (BT) segmentation Or triple-tree (TT) segmentation, or any combination thereof, and for performing predictions for, for example, block partitions or each of the sub-blocks, where the mode selection includes selecting the tree structure of the segmented image block 203 and selecting the application A prediction mode for each of a block partition or a sub-block.
  • 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 configured to receive or obtain 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 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 configured to obtain an inter prediction parameter, and obtain an inter prediction block 245 based on or using the inter prediction parameter to perform inter prediction.
  • Motion compensation performed by a motion compensation unit may include taking out or generating a prediction block based on a motion / block vector determined through motion estimation (possibly performing interpolation on 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.
  • the motion compensation unit 246 may also generate syntax elements associated with the blocks and video slices for use by the decoder 30 when decoding picture blocks of the video slices.
  • the above-mentioned 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). In a possible application scenario, if there is only one inter prediction mode, the inter prediction parameters may not be carried in the syntax element. At this time, the decoding end 30 may directly use the default prediction mode for decoding. It can be understood that the inter prediction unit 244 can be used to perform any combination of inter prediction techniques.
  • the intra prediction unit 254 is configured to obtain, 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 an optimization criterion, such as based on a minimum residual (eg, an intra-prediction mode that provides a prediction block 255 most similar to the current picture block 203) or a minimum code rate distortion.
  • an optimization criterion such as based on a minimum residual (eg, an intra-prediction mode that provides a prediction block 255 most similar to the current picture block 203) or a minimum code rate distortion.
  • the intra prediction unit 254 is further configured 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 further configured 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 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). In a possible application scenario, if there is only one intra prediction mode, the intra prediction parameters may not be carried in the syntax element. At this time, the decoding end 30 may directly use the default prediction mode for decoding.
  • 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 end 30 may directly use the default prediction mode for decoding.
  • the entropy coding unit 270 is configured to apply an entropy coding algorithm or scheme (for example, a variable length coding (VLC) scheme, a context adaptive VLC (context adaptive VLC, CAVLC) scheme, an arithmetic coding scheme, and a context adaptive binary arithmetic Coding (context, adaptive binary coding, CABAC), syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval partitioning entropy (PIPE) coding, or other entropy Encoding method or technique) applied to one or all of the quantized residual coefficients 209, inter prediction parameters, intra prediction parameters, and / or loop filter parameters (or not applied) to obtain
  • VLC variable length coding
  • CAVLC context adaptive VLC
  • CABAC syntax-based context-adaptive binary arithmetic coding
  • PIPE probability interval partitioning entropy
  • the encoded picture data 21 is output in the form of, for example, an encoded bit stream 21.
  • the encoded bitstream may be transmitted to video decoder 30 or archived for later transmission or retrieval by video decoder 30.
  • the entropy encoding unit 270 may also be used to entropy encode other syntax elements of the current video slice that is being encoded.
  • video encoder 20 may be used to encode a video stream.
  • the non-transform-based encoder 20 may directly quantize the residual signal without a 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 configured to implement a motion vector prediction method based on an affine motion model described in the embodiments below.
  • the video decoder 30 is configured to receive, for example, encoded picture data (eg, an encoded bit stream) 21 encoded by the encoder 20 to obtain a decoded picture 231.
  • encoded picture data eg, an encoded bit stream
  • video decoder 30 receives video data from video encoder 20, such as an encoded video bitstream and associated syntax elements representing picture blocks of encoded video slices.
  • 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, 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 substantially inverse to the encoding pass described with reference to video encoder 20 of FIG. 2.
  • the entropy decoding unit 304 is configured 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 , (Filtered) any or all of the loop filter parameters and / or other syntax elements.
  • the entropy decoding unit 304 is further configured to forward the inter prediction parameters, the 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 transformation processing unit 312 may be functionally the same as the inverse transformation 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.
  • the inter prediction unit 344 may be functionally similar to the inter prediction unit 244 and the intra prediction unit 354 may be functionally similar to the intra prediction unit 254.
  • the prediction processing unit 360 is generally used to perform block prediction and / or obtain a prediction block 365 from the encoded data 21, and to receive or obtain prediction-related parameters from, for example, an entropy decoding unit 304 (explicitly or implicitly) and / or Information about the selected prediction mode.
  • the intra-prediction unit 354 of the prediction processing unit 360 is used for the intra-prediction mode based on the signal representation and the previously decoded block from the current frame or picture Data to generate a prediction block 365 for a picture block of the current video slice.
  • the inter-prediction unit 344 e.g., a motion compensation unit
  • the other syntax elements generate a prediction block 365 for a 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 a reference frame list using a default construction technique based on the reference pictures stored in the DPB 330: List 0 and List 1.
  • the prediction processing unit 360 is configured to determine prediction information for a video block of a current video slice by analyzing a motion vector and other syntax elements, and use the prediction information to generate a prediction block for a current video block that is being decoded.
  • the prediction processing unit 360 uses some of the received syntax elements to determine a prediction mode (e.g., intra or inter prediction), an inter prediction slice type ( (E.g., B slice, P slice, or GPB slice), construction information for one or more of the reference picture lists for the slice, motion vectors for each inter-coded video block for the slice, 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.
  • a prediction mode e.g., intra or inter prediction
  • an inter prediction slice type (E.g., B slice, P slice, or GPB slice)
  • construction information for one or more of the reference picture lists for the slice motion vectors for each inter-coded video block for the slice
  • the syntax elements received by the video decoder 30 from the bitstream include receiving an adaptive parameter set (APS), a sequence parameter set (SPS), and a picture parameter set (picture parameter set (PPS) or syntax element in one or more of the slice headers.
  • APS adaptive parameter set
  • SPS sequence parameter set
  • PPS picture parameter set
  • the inverse quantization unit 310 may be used for inverse quantization (ie, inverse quantization) of 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 video encoder 20 for each video block in the video slice to determine the degree of quantization that should be applied and also to determine the degree of inverse quantization that should be applied.
  • the inverse transform processing unit 312 is configured to apply an inverse transform (for example, an inverse DCT, an inverse integer transform, or a conceptually similar inverse transform process) to the transform coefficients to generate a residual block in the pixel domain.
  • an inverse transform for example, an inverse DCT, an inverse integer transform, or a conceptually similar inverse transform process
  • Reconstruction unit 314 (e.g., summer 314) is used to add inverse transform block 313 (i.e., reconstructed residual block 313) to prediction block 365 to obtain reconstructed block 315 in the sample domain, such as 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 or after the encoding cycle) is used to filter the reconstructed block 315 to obtain the filtered block 321 so as 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 a deblocking filter, a sample-adaptive offset (SAO) filter, or other filters such as a bilateral filter, Adaptive loop filters (adaptive loop filters, ALF), or sharpening or smoothing filters, or cooperative filters.
  • 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 a decoded picture 31 through an output 332 for presentation to or review by a user.
  • video decoder 30 may be used to decode the compressed bitstream.
  • the decoder 30 may generate an 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 configured to implement the motion vector prediction method based on the affine motion model described in the embodiments below.
  • FIG. 4 is a schematic structural diagram of a video decoding device 400 (such as a video encoding device 400 or a video decoding device 400) according to an embodiment of the present invention.
  • Video coding device 400 is adapted to implement the embodiments described herein.
  • the video coding device 400 may be a video decoder (such as the decoder 30 of FIG. 1A) or a video encoder (such as the 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 entry port 410 and a receiving unit (Rx) 420 for receiving data, a processor, a logic unit or a central processing unit (CPU) 430 for processing data, and a transmitter unit for transmitting data (Tx) 440 and egress port 450, and a memory 460 for storing data.
  • the video decoding device 400 may further include a photoelectric conversion component and an electro-optic (EO) component coupled with the entrance port 410, the receiver unit 420, the transmitter unit 440, and the exit port 450 for an exit or entrance of an optical signal or an electric signal.
  • EO electro-optic
  • 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), FPGAs, ASICs, and DSPs.
  • the processor 430 is in communication with the ingress port 410, the receiver unit 420, the transmitter unit 440, the egress port 450, and the memory 460.
  • the processor 430 includes a decoding module 470 (eg, an encoding module 470 or a decoding module 470).
  • the encoding / decoding module 470 implements the embodiments disclosed herein to implement the chroma block prediction method provided by the embodiments of the present invention.
  • the encoding / decoding module 470 implements, processes, or provides various encoding operations.
  • the function of the video decoding device 400 is substantially improved through the encoding / decoding module 470, and the transition of the video decoding device 400 to different states is affected.
  • 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, which can be used as overflow data storage devices for storing programs when these programs are selectively executed, and for storing instructions and data read during program execution.
  • the memory 460 may be volatile and / or non-volatile, and may be a read-only memory (ROM), a random access memory (RAM), a random content-addressable memory (TCAM), and / or a static state. 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 may implement the technology of the present application.
  • the device 500 for implementing chroma block prediction may be in the form of a computing system including a plurality of computing devices, or in a mobile phone, tablet computer, laptop computer, notebook computer, desktop The form of a single computing device, such as a computer.
  • the processor 502 in the apparatus 500 may be a central processing unit.
  • the processor 502 may be any other type of device or multiple devices capable of manipulating or processing information, existing or to be developed in the future.
  • speed and efficiency advantages can be achieved using more than one processor.
  • the memory 504 in the device 500 may be a read-only memory (ROM) device or a random access memory (RAM) device. Any other suitable type of storage device can be used as the memory 504.
  • the memory 504 may include code and data 506 accessed by the processor 502 using the bus 512.
  • the memory 504 may further include an operating system 508 and an application program 510, which contains at least one program that permits the processor 502 to perform the methods described herein.
  • the application program 510 may include applications 1 to N, and applications 1 to N further include a video encoding application that performs the methods described herein.
  • the device 500 may also include additional memory in the form of a slave memory 514, which may be, for example, a memory card for use with a mobile computing device. Because a video communication session may contain a large amount of information, this information may be stored in whole or in part in the slave memory 514 and loaded into the memory 504 for processing as needed.
  • the apparatus 500 may also include one or more output devices, such as a display 518.
  • the display 518 may be a touch-sensitive display combining a display and a touch-sensitive element operable to sense a touch input.
  • the display 518 may be coupled to the processor 502 through a bus 512.
  • other output devices may be provided that allow the user to program or otherwise use the device 500, or provide other output devices as an alternative to the display 518.
  • the display can be implemented in different ways, including through a liquid crystal display (LCD), a cathode-ray tube (CRT) display, a plasma display, or a light emitting diode diode (LED) displays, such as organic LED (OLED) displays.
  • LCD liquid crystal display
  • CTR cathode-ray tube
  • plasma display a plasma display
  • LED light emitting diode diode
  • OLED organic LED
  • the apparatus 500 may further include or be in communication with an image sensing device 520, such as a camera or any other image sensing device 520 that can or will be developed in the future to sense an image, such as An image of a user running the device 500.
  • the image sensing device 520 may be placed directly facing a user of the running apparatus 500.
  • the position and optical axis of the image sensing device 520 may be configured such that its field of view includes an area immediately adjacent to the display 518 and the display 518 is visible from the area.
  • the device 500 may also include or be in communication with a sound sensing device 522, such as a microphone or any other sound sensing device that can or will be developed in the future to sense the sound near the device 500.
  • the sound sensing device 522 may be placed directly facing the user of the operating device 500 and may be used to receive a sound, such as a voice or other sound, emitted by the user when the device 500 is running.
  • the processor 502 and the memory 504 of the apparatus 500 are shown in FIG. 5 as being integrated in a single unit, other configurations may be used.
  • the operation of the processor 502 may be distributed among multiple directly-coupled machines (each machine has one or more processors), or distributed in a local area or other network.
  • the memory 504 may be distributed among multiple machines, such as a network-based memory or a memory among multiple machines running the apparatus 500.
  • the bus 512 of the device 500 may be formed by multiple buses.
  • the slave memory 514 may be directly coupled to other components of the device 500 or may be accessed through a network, and may include a single integrated unit, such as one memory card, or multiple units, such as multiple memory cards. Therefore, the apparatus 500 can be implemented in various configurations.
  • inter prediction modes In order to better understand the technical solutions of the embodiments of the present invention, the inter prediction modes, non-translational motion models, inherited control point motion vector prediction methods, and constructed control point motion vector prediction methods according to the embodiments of the present invention are further described below.
  • Inter prediction mode In HEVC, two inter prediction modes are used, which are advanced motion vector prediction (AMVP) mode and merge mode.
  • AMVP advanced motion vector prediction
  • the AMVP mode For the AMVP mode, it first traverses the spatially or temporally adjacent coded blocks of the current block (denoted as neighboring blocks), and builds a candidate motion vector list (also referred to as a motion information candidate list) based on the motion information of each neighboring block. Then, the optimal motion vector is determined from the candidate motion vector list by the rate distortion cost, and the candidate motion information with the lowest rate distortion cost is used as the motion vector predictor (MVP) of the current block. Among them, the positions of the neighboring blocks and their traversal order are all predefined.
  • the rate-distortion cost is calculated by formula (1), where J represents the rate-distortion cost RD Cost, SAD is the sum of the absolute error between the predicted pixel value and the original pixel value obtained after motion estimation using the candidate motion vector prediction value (sum of absolute differences (SAD), where R is the code rate and ⁇ is the Lagrangian multiplier.
  • the encoding end passes the index value of the selected motion vector prediction value in the candidate motion vector list and the reference frame index value to the decoding end. Further, a motion search is performed in a neighborhood centered on the MVP to obtain the actual motion vector of the current block, and the encoder transmits the difference between the MVP and the actual motion vector (motion vector difference) to the decoder.
  • the motion information of the current block in the spatial or time-domain adjacent coded blocks is used to construct a list of candidate motion vectors, and then the optimal motion information is determined from the list of candidate motion vectors by calculating the rate-distortion cost as the current block's The motion information, and then the index value of the position of the optimal motion information in the candidate motion vector list (referred to as merge index, the same applies hereinafter) to the decoding end.
  • merge index the same applies hereinafter
  • the spatial and temporal candidate motion information of the current block is shown in Figure 6.
  • the spatial motion candidate motion information comes from the spatially neighboring 5 blocks (A0, A1, B0, B1, and B2).
  • the motion information of the neighboring block is not added to the candidate motion vector list.
  • the time-domain candidate motion information of the current block is obtained after scaling the MV of the corresponding position block in the reference frame according to the reference frame and the picture order count (POC) of the current frame.
  • POC picture order count
  • the positions of the neighboring blocks in the Merge mode and their traversal order are also predefined, and the positions of the neighboring blocks and their traversal order may be different in different modes.
  • all pixels in the coding block use the same motion information (that is, the motion of all pixels in the coding block is consistent), and then motion compensation is performed according to the motion information to obtain the predicted value of the pixels of the coding block. .
  • motion compensation is performed according to the motion information to obtain the predicted value of the pixels of the coding block.
  • not all pixels in a coded block have the same motion characteristics. Using the same motion information may cause inaccurate motion compensation predictions, which may increase residual information.
  • the existing video coding standards use block-matched motion estimation based on translational motion models.
  • non-translational motion objects such as rotating objects. Roller coasters that rotate in different directions, fireworks and some special effects in movies, especially moving objects in UGC scenes, if they are coded, if the block motion compensation technology based on translational motion models in the current coding standard is used, The encoding efficiency will be greatly affected. Therefore, non-translational motion models, such as affine motion models, are generated to further improve the encoding efficiency.
  • AMVP modes can be divided into AMVP modes based on translational models and AMVP modes based on non-translational models;
  • Merge modes can be divided into Merge modes based on translational models and non-translational movement models.
  • Merge mode can be divided into Merge modes based on translational models and non-translational movement models.
  • Non-translational motion model prediction refers to the use of the same motion model at the codec side to derive the motion information of each sub-motion compensation unit in the current block, and perform motion compensation based on the motion information of the sub-motion compensation unit to obtain a prediction block, thereby improving prediction effectiveness.
  • the sub-motion compensation unit involved in the embodiment of the present invention may be a pixel or a pixel block of size N 1 ⁇ N 2 divided according to a specific method, where N 1 and N 2 are both positive integers and N 1 It may be equal to N 2 or not equal to N 2 .
  • non-translational motion models are 4-parameter affine motion models or 6-parameter affine motion models. In possible application scenarios, there are also 8-parameter bilinear models. Each will be described below.
  • the 4-parameter affine motion model can be represented by the motion vector of two pixels and their coordinates relative to the top left vertex pixel of the current block.
  • the pixels used to represent the parameters of the motion model are called control points. If the upper left vertex (0,0) and upper right vertex (W, 0) pixels are used as control points, first determine the motion vectors (vx0, vy0) and (vx1, vy1) of the upper left vertex and upper right vertex control points of the current block. Then, the motion information of each sub motion compensation unit in the current block is obtained according to the following formula (3), where (x, y) is the coordinates of the sub motion compensation unit relative to the top left pixel of the current block, and W is the width of the current block.
  • the 6-parameter affine motion model is shown in the following formula (4):
  • the 6-parameter affine motion model can be represented by the motion vector of three pixels and its coordinates relative to the top left vertex pixel of the current block. If the upper left vertex (0,0), upper right vertex (W, 0), and lower left vertex (0, H) pixels are used as control points, the motion vectors of the upper left vertex, upper right vertex, and lower left vertex control points of the current block are determined respectively.
  • the 8-parameter bilinear model is shown in the following formula (6):
  • the 8-parameter bilinear model can be represented by the motion vector of four pixels and its coordinates relative to the top left vertex pixel of the current coding block. If the top left vertex (0,0), top right vertex (W, 0), bottom left vertex (0, H), and bottom right fixed point (W, H) are used as control points, then the top left vertex, top right of the current coding block are determined first.
  • the motion information of each sub motion compensation unit where (x, y) is the coordinates of the top left pixel of the sub motion compensation unit relative to the current coding block, and W and H are the width and height of the current coding block, respectively.
  • the coding block predicted by the affine motion model can also be called an affine coding block.
  • the affine motion model is directly related to the motion information of the control points of the affine coding block.
  • the AMVP mode based on the affine motion model or the Merge mode based on the affine motion model can be used to obtain the motion information of the control points of the affine coding block. Further, for the AMVP mode based on the affine motion model or the Merge mode based on the affine motion model, the motion information of the control points of the current coding block can be obtained by the inherited control point motion vector prediction method or the constructed control point motion vector prediction method. get. These two methods are described further below.
  • the inherited control point motion vector prediction method refers to using a motion model of an adjacent affine-coded block of a current block to determine a candidate control point motion vector of the current block.
  • Affine coding block to obtain control point motion information of the affine coding block, and then use the motion model constructed by the control point motion information of the affine coding block to derive the control point motion vector (for Merge mode) or control of the current block Point motion vector prediction (for AMVP mode).
  • A1 ⁇ B1 ⁇ B0 ⁇ A0 ⁇ B2 is only an example, and the order of other combinations is also applicable to the embodiment of the present invention.
  • the adjacent position blocks are not limited to A1, B1, B0, A0, and B2.
  • the adjacent position block may be a pixel point, or a pixel block of a preset size divided according to a specific method, such as a 4x4 pixel block, a 4x2 pixel block, or other sizes. Pixel blocks are not limited.
  • the affine coding block is an already coded block (also referred to as an adjacent affine coding block) that is adjacent to the current block and is predicted by using an affine motion model in the encoding stage.
  • the motion vector (vx4) of the upper left vertex (x4, y4) of the affine coding block is obtained.
  • vy4 the motion vector (vx5, vy5) of the upper right vertex (x5, y5).
  • the combination of the motion vector (vx0, vy0) of the upper left vertex (x0, y0) of the current block and the motion vector (vx1, vy1) of the upper right vertex (x1, y1) obtained based on the affine coding block where A1 is located as above is the current Candidate control point motion vector for the block.
  • the motion vector (vx4) of the upper left vertex (x4, y4) of the affine coding block is obtained.
  • vy4 the motion vector (vx5, vy5) of the upper right vertex (x5, y5), and the motion vector (vx6, vy6) of the lower left vertex (x6, y6).
  • the motion vector (vx1, vy1) of the upper-right vertex (x1, y1), and the lower left of the current block is the candidate control point motion vector of the current block.
  • the constructed control point motion vector prediction method refers to combining the motion vectors of neighboring coded blocks around the control points of the current block as the motion vectors of the control points of the current affine coding block, without considering the neighboring neighboring coded Whether the block is an affine coded block.
  • the control point motion vector prediction methods constructed are different, which are described below respectively.
  • the motion vectors of the upper left vertex and the upper right vertex of the current block are determined by using the motion information of the coded blocks adjacent to the current coded block. It should be noted that FIG. 8 is only used as an example.
  • the motion vector of the block A2, B2, or B3 adjacent to the top-left vertex can be used as the top-left vertex of the current block.
  • the candidate motion vector of the motion vector of; the motion vector of the upper right vertex adjacent to the encoded block B1 or B0 block is used as the candidate motion vector of the upper right vertex of the current block.
  • the candidate motion vectors of the upper left vertex and the upper right vertex are combined to form a plurality of two-tuples.
  • the motion vectors of two coded blocks included in the tuple can be used as candidate control point motion vectors of the current block.
  • the two-tuple can be seen in the following (13A):
  • v A2 represents the motion vector of A2
  • v B1 represents the motion vector of B1
  • v B0 represents the motion vector of B0
  • v B2 represents the motion vector of B2
  • v B3 represents the motion vector of B3.
  • the motion vector of the block A2, B2, or B3 adjacent to the top-left vertex can be used as the top-left vertex of the current block
  • the motion vector serves as a candidate motion vector for the motion vector of the lower left vertex of the current block.
  • the above candidate motion vectors of the upper left vertex, the upper right vertex, and the lower left vertex are combined to form multiple triples.
  • the motion vectors of the three coded blocks included in the triple can be used as candidate control point motion vectors for the current block.
  • the multiple triples can be seen in the following formulas (13B) and (13C):
  • v A2 indicates the motion vector of A2
  • v B1 indicates the motion vector of B1
  • v B0 indicates the motion vector of B0
  • v B2 indicates the motion vector of B2
  • v B3 indicates the motion vector of B3
  • v A0 indicates the motion vector of A0
  • v A1 represents the motion vector of A1.
  • control point motion vectors may also be applied to the embodiments of the present invention, and details are not described herein.
  • a control point motion vector prediction method based on the construction of the Merge mode of the affine motion model is described below.
  • the motion vectors of the upper-left vertex and the upper-right vertex of the current block are determined using the motion information of the encoded blocks around the current encoding block. It should be noted that FIG. 9 is only used as an example.
  • A0, A1, A2, B0, B1, B2, and B3 are the spatially adjacent positions of the current block and are used to predict CP1, CP2, or CP3;
  • T is the temporally adjacent positions of the current block and used to predict CP4.
  • the coordinates of CP1, CP2, CP3, and CP4 are (0,0), (W, 0), (H, 0), and (W, H), where W and H are the width and height of the current block. Then for each control point of the current block, its motion information is obtained in the following order:
  • the check order is B2-> A2-> B3. If B2 is available, then the motion information of B2 is used. Otherwise, detect A2, B3. If motion information is not available at all three locations, CP1 motion information cannot be obtained.
  • the check sequence is B0-> B1; if B0 is available, CP2 uses the motion information of B0. Otherwise, detect B1. If motion information is not available at both locations, CP2 motion information cannot be obtained.
  • the detection sequence is A0-> A1;
  • X can be obtained to indicate that the block including the position of X (X is A0, A1, A2, B0, B1, B2, B3, or T) has been encoded and adopts the inter prediction mode; otherwise, the X position is not available. It should be noted that other methods for obtaining motion information of the control points may also be applied to the embodiments of the present invention, and details are not described herein.
  • the motion information of the control points of the current block is combined to obtain the structured control point motion information.
  • a 4-parameter affine motion model is used in the current block, the motion information of the two control points of the current block is combined to form a two-tuple for constructing a 4-parameter affine motion model.
  • the combination of the two control points can be ⁇ CP1, CP4 ⁇ , ⁇ CP2, CP3 ⁇ , ⁇ CP1, CP2 ⁇ , ⁇ CP2, CP4 ⁇ , ⁇ CP1, CP3 ⁇ , ⁇ CP3, CP4 ⁇ .
  • Affine CP1, CP2
  • the motion information of the three control points of the current block is combined to form a triplet, which is used to construct a 6-parameter affine motion model.
  • the combination of the three control points can be ⁇ CP1, CP2, CP4 ⁇ , ⁇ CP1, CP2, CP3 ⁇ , ⁇ CP2, CP3, CP4 ⁇ , ⁇ CP1, CP3, CP4 ⁇ .
  • a 6-parameter affine motion model constructed using a triple of CP1, CP2, and CP3 control points can be written as Affine (CP1, CP2, CP3).
  • a quadruple formed by combining the motion information of the four control points of the current block is used to build an 8-parameter bilinear model.
  • An 8-parameter bilinear model constructed using a quaternion of CP1, CP2, CP3, and CP4 control points is denoted as Bilinear (CP1, CP2, CP3, CP4).
  • the motion information combination of two control points is simply referred to as a tuple, and the motion information of three control points (or two coded blocks) is combined. It is abbreviated as a triple, and the combination of motion information of four control points (or four coded blocks) is abbreviated as a quad.
  • CurPoc represents the POC number of the current frame
  • DesPoc represents the POC number of the reference frame of the current block
  • SrcPoc represents the POC number of the reference frame of the control point
  • MV s represents the scaled motion vector
  • MV represents the motion vector of the control point.
  • control points can also be converted into a control point at the same position.
  • the 4-parameter affine motion model obtained by combining ⁇ CP1, CP4 ⁇ , ⁇ CP2, CP3 ⁇ , ⁇ CP2, CP4 ⁇ , ⁇ CP1, CP3 ⁇ , ⁇ CP3, CP4 ⁇ is converted to ⁇ CP1, CP2 ⁇ or ⁇ CP1, CP2, CP3 ⁇ .
  • the conversion method is to substitute the motion vector of the control point and its coordinate information into the above formula (2) to obtain the model parameters, and then substitute the coordinate information of ⁇ CP1, CP2 ⁇ into the above formula (3) to obtain its motion vector.
  • the conversion can be performed according to the following formulas (15)-(23), where W represents the width of the current block, H represents the height of the current block, and in formulas (15)-(23), (vx 0 , vy 0) denotes a motion vector CP1, (vx 1, vy 1) CP2 represents a motion vector, (vx 2, vy 2) represents the motion vector of CP3, (vx 3, vy 3) denotes the motion vector of CP4.
  • ⁇ CP1, CP3 ⁇ conversion ⁇ CP1, CP2 ⁇ or ⁇ CP1, CP2, CP3 ⁇ can be realized by the following formula (16):
  • the conversion from ⁇ CP2, CP4 ⁇ to ⁇ CP1, CP2 ⁇ can be realized by the following formula (20), and the conversion from ⁇ CP2, CP4 ⁇ to ⁇ CP1, CP2, CP3 ⁇ can be realized by the formulas (20) and (21):
  • the 6-parameter affine motion model combined with ⁇ CP1, CP2, CP4 ⁇ , ⁇ CP2, CP3, CP4 ⁇ , ⁇ CP1, CP3, CP4 ⁇ is converted into a control point ⁇ CP1, CP2, CP3 ⁇ to represent it.
  • the conversion method is to substitute the motion vector of the control point and its coordinate information into the above formula (4) to obtain the model parameters, and then substitute the coordinate information of ⁇ CP1, CP2, CP3 ⁇ into the formula (5) to obtain its motion vector.
  • the conversion can be performed according to the following formulas (24)-(26), where W represents the width of the current block and H represents the height of the current block.
  • (vx 0 , vy 0) denotes a motion vector CP1
  • (vx 1, vy 1) CP2 represents a motion vector
  • (vx 2, vy 2) represents the motion vector of CP3
  • (vx 3, vy 3) denotes the motion vector of CP4.
  • the candidate motion vector list is empty at this time, add the candidate control point motion information to the candidate motion vector list; otherwise, iterate through the motion information in the candidate motion vector list and check the candidate motion vectors. Does the list have the same motion information as the candidate control point motion information? If the candidate motion vector list does not have the same motion information as the candidate control point motion information, the candidate control point motion information is added to the candidate motion vector list.
  • the maximum list length such as MaxAffineNumMrgCand
  • a preset sequence is as follows: Affine (CP1, CP2, CP3) ⁇ Affine (CP1, CP2, CP4) ⁇ Affine (CP1, CP3, CP4) ⁇ Affine (CP2, CP3, CP4) ⁇ Affine (CP2, CP3, CP4) ⁇ Affine (CP1, CP2) ⁇ Affine (CP1, CP3) ⁇ Affine (CP2, CP3) ⁇ Affine (CP1, CP4) ⁇ Affine (CP2, CP4) ⁇ Affine (CP3, CP4), a total of 10 combinations.
  • control point motion information corresponding to a combination is not available, the combination is considered to be unavailable. If a combination is available, determine the reference frame index of the combination (when two control points, the smallest reference frame index is selected as the reference frame index of the combination; when it is greater than two control points, the reference frame index with the most occurrences is selected first. If there are as many occurrences of multiple reference frame indexes, the one with the smallest reference frame index is selected as the combined reference frame index), and the motion vector of the control point is scaled. If the motion information of all control points after scaling is consistent, the combination is illegal.
  • the embodiment of the present invention can also fill the candidate motion vector list.
  • the length of the candidate motion vector list at this time is less than the maximum list length (such as MaxAffineNumMrgCand). Fill until the length of the list is equal to the maximum list length.
  • It can be filled by a method of supplementing zero motion vectors, or by a method of combining and weighted average of motion information of existing candidates in an existing list. It should be noted that other methods for obtaining candidate motion vector list filling can also be applied to the embodiments of the present invention, and details are not described herein.
  • AMVP mode (Affine AMVP mode) based on the affine motion model
  • Merge mode (Affine Merge mode) based on the affine motion model
  • the inherited control point motion vector prediction method and / or the constructed control point motion vector prediction method may be used to construct a candidate motion vector list of the AMVP mode based on the affine motion model.
  • the candidate motion vector list of the AMVP mode based on the affine motion model may be referred to as a control point motion vector predictor candidate list (control point motion vector predictor list), and the control point motion vector prediction value in the list Including 2 (as in the case where the current block is a 4-parameter affine motion model) candidate control point motion vector or includes 3 (as in the case where the current block is 6 parameter affine motion model) candidate control point motion vectors.
  • the candidate list of control point motion vector prediction values can also be pruned and sorted according to a specific rule, and it can be truncated or filled to a specific number.
  • the encoder uses each control point motion vector prediction value in the control point motion vector prediction value candidate list to obtain the current value by formula (3) or (5) or (7)
  • the motion vector of each sub-motion compensation unit in the block is coded, and then the pixel value of the corresponding position in the reference frame pointed by the motion vector of each sub-motion compensation unit is used as its prediction value to perform motion compensation using the affine motion model.
  • Calculate the average value of the difference between the original value and the predicted value of each pixel in the current coding block select the control point motion vector prediction value corresponding to the smallest average value as the optimal control point motion vector prediction value, and use it as the current encoding Block 2 or 3 or 4 control point motion vector predictions.
  • control point motion vector prediction value is used as the search starting point to perform a motion search within a certain search range to obtain control point motion vectors (CPMV), and calculate the control point motion vector and control point motion vector.
  • CPMV control point motion vectors
  • CPMVD difference between the predicted values (control points, motion vectors, differences)
  • the encoder passes the index number indicating the position of the control point motion vector prediction value in the control point motion vector prediction value candidate list and the CPMVD encoded input code stream to the decoding end.
  • the decoder (such as the aforementioned decoder 30) parses and obtains the index number and the control point motion vector difference (CPMVD) in the code stream, and determines the control point motion vector from the control point motion vector prediction value candidate list according to the index number.
  • Predictor control point motion vector predictor, CPMVP
  • the inherited control point motion vector prediction method and / or the constructed control point motion vector prediction method can be used to construct a control point motion vector fusion candidate list.
  • control point motion vector fusion candidate list can be pruned and sorted according to a specific rule, and it can be truncated or filled to a specific number.
  • the encoder uses each control point motion vector in the fusion candidate list to obtain each sub-motion compensation in the current encoding block by formula (3) or (5) or (7)
  • the motion vector of a unit (a pixel or a pixel block of size N 1 ⁇ N 2 divided by a specific method), and then obtain the pixel value of the position in the reference frame pointed to by the motion vector of each sub motion compensation unit as its prediction value, Perform affine motion compensation.
  • An index number indicating the position of the control point motion vector in the candidate list is encoded into the code stream and sent to the decoding end.
  • a decoder (such as the aforementioned decoder 30) parses the index number and determines a control point motion vector (CPMV) from a control point motion vector fusion candidate list according to the index number.
  • CPMV control point motion vector
  • At least one (a) of a, b, or c can be expressed as: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple .
  • the encoding end may use syntax elements to indicate to the decoding end the inter prediction mode of the current block, the affine motion model adopted by the current block, and other related information.
  • ae (v) represents a syntax element using context-based adaptive binary coding (cabac) coding.
  • x0, y0 represent the coordinates of the current block in the video image.
  • the condition for adopting the merge mode based on the affine motion model may be that the width and height of the current block are both greater than or equal to 8.
  • cbWidth represents the width of the current block
  • the syntax element affine_merge_flag [x0] [y0] may be used to indicate whether a merge mode based on an affine motion model is adopted for the current block.
  • the type (slice_type) of the slice where the current block is located is P type or B type.
  • affine_merge_flag [x0] [y0] 1 indicates that the merge mode based on the affine motion model is used for the current block
  • affine_merge_flag [x0] [y0] 0 indicates that the merge mode based on the affine motion model is not used for the current block. You can use the merge mode of the leveling motion model.
  • the syntax element merge_idx [x0] [y0] can be used to indicate the index value for the merge candidate list.
  • the syntax element affine_merge_idx [x0] [y0] can be used to indicate the index value for the affine merge candidate list.
  • affine_inter_flag [x0] [y0] may be used to indicate whether the affine motion model based AMVP mode is used for the current block when the current block is a P-type or B-type slice.
  • affine_inter_flag [x0] [y0] 0 indicates that the AMVP mode based on affine motion model is used for the current block
  • affine_type_flag [x0] [y0] can be used to indicate whether a 6-parameter affine motion model is used for motion compensation for the current block when the current block is a P-type or B-type slice.
  • affine_type_flag [x0] [y0] 0, indicating that the 6-parameter affine motion model is not used for motion compensation for the current block, and only 4-parameter affine motion model can be used for motion compensation;
  • affine_type_flag [x0] [y0] 1, indicating that A 6-parameter affine motion model is used for motion compensation for the current block.
  • MaxNumMergeCand and MaxAffineNumMrgCand are used to indicate the maximum list length, indicating the maximum length of the constructed candidate motion vector list.
  • inter_pred_idc [x0] [y0] is used to indicate the prediction direction.
  • PRED_L1 is used to indicate backward prediction.
  • num_ref_idx_l0_active_minus1 indicates the number of reference frames in the forward reference frame list
  • ref_idx_l0 [x0] [y0] indicates the forward reference frame index value of the current block.
  • mvd_coding (x0, y0,0,0) indicates the first motion vector difference.
  • mvp_l0_flag [x0] [y0] indicates the forward MVP candidate list index value.
  • PRED_L0 indicates forward prediction.
  • num_ref_idx_l1_active_minus1 indicates the number of reference frames in the backward reference frame list.
  • ref_idx_l1 [x0] [y0] indicates the backward reference frame index value of the current block, and
  • mvp_l1_flag [x0] [y0] indicates the backward MVP candidate list index value.
  • MotionModelIdc [x0] [y0] 1 indicates that a 4-parameter affine motion model is used
  • Tables 1 and 2 are merely examples. In practical applications, the above Tables 1 and 2 can also include more or less content.
  • MotionModelIdc [x0] [y0] in Table 2 may also include other values, which can be used to indicate the use of 8-parameter bilinearity. Models, etc.
  • the encoder or decoder After the encoder or decoder obtains the motion vector value of each sub-block of the current block through the inter prediction mode, it needs to store it for subsequent motion compensation; at the same time, the obtained motion vector value It will also be used in other subsequent decoding processes, such as motion vector prediction in the decoding process of neighboring blocks, and filtering strength decision for deblocking filtering.
  • the obtained motion vector of the control point of the current block also needs to be stored for use by subsequent adjacent to-be-encoded blocks when using the inherited control point motion vector prediction method. Therefore, at this time, for the current block, there are two types of motion vectors: the motion vector of each sub-block, and the motion vector of the control point.
  • the motion vectors of the control points are used to cover the motion vectors of the subblocks in which they are located. For example, if the affine motion model used by the current affine decoding block is a 4 affine motion model, the motion vectors of the top left subblock and the top right subblock are set as the motion vectors of the top left and top right vertex control points. If the affine motion model used by the current affine decoding block is a 6-affine motion model, the motion vectors of the top left subblock, the top right subblock, and the bottom left subblock are set as the motion vectors of the top left, top right, and bottom left vertex control points.
  • this method should solve the problem of motion vector storage, because the sub-block where the control point is located uses motion vectors that are inconsistent with other sub-blocks for motion compensation, the prediction is inaccurate, which reduces the coding efficiency.
  • the embodiments of the present invention perform the method of predicting control point motion vectors inherited as described above. Improve.
  • the improved inherited control point motion vector prediction method does not need to use the neighboring affine coding block (or the neighboring affine decoding block) in the process of determining the candidate control point motion vector of the current block.
  • the motion vector of the control point is the motion vector of at least two sub-blocks of the adjacent affine coding block (or the adjacent affine decoding block) to derive the candidate control point motion vector of the current block.
  • the motion vector of the control point does not need to be stored, that is, the motion vector of the control point of the current block is only used for
  • the derivation of the motion vectors of the sub-blocks of the current block will not be used for the prediction of motion vectors of other neighboring blocks to be processed. Therefore, the solution of the present invention only needs to save the motion vectors of the sub-blocks, and uses the motion vectors of the sub-blocks for motion compensation, while solving the problem of motion vector storage, it also improves prediction accuracy and coding efficiency.
  • the adjacent affine coding block is a coded block adjacent to the current block that is predicted by using an affine motion model during the encoding phase
  • the adjacent affine decoding block is a current block that is predicted by using an affine motion model during the decoding phase.
  • the decoded block adjacent to the block W can be used to express the width of the current block
  • H can be used to express the height of the current block.
  • U can be used to express the width of adjacent affine decoding blocks
  • V can be used to express the height of adjacent affine decoding blocks.
  • the adjacent affine decoding block is a 4-parameter affine decoding block
  • the horizontal coordinate distance of the center point of the subblock in the adjacent affine decoding block is P and the two subblocks with the same vertical coordinate are obtained.
  • the motion vector and the coordinates of its center point constitute a 4-parameter affine motion model, which is used to derive the motion vector of the control point of the current affine decoding block, where P is smaller than the width U of the adjacent affine decoding block, and P is 2 Power of.
  • the adjacent affine decoding block is a 4-parameter affine decoding block
  • two sub-blocks having the same horizontal coordinates and a vertical coordinate distance of Q as the center points of the sub-blocks in the adjacent affine-coding block are obtained.
  • the motion vector and the coordinates of its center point form a 4-parameter affine motion model, which is used to derive the motion vector of the control point of the current affine decoding block, where Q is less than the height V of the adjacent affine decoding block, and Q is Power of two.
  • the neighboring affine decoding block is a 6-parameter affine decoding block
  • two sub-blocks with the horizontal coordinate distance P of the sub-block center point in the neighboring affine decoding block and the same vertical coordinates Such as the motion vector of the first sub-block and the second sub-block, respectively, and the coordinates of their center points, and then obtain the horizontal coordinates of the sub-block center points in the adjacent affine decoding block that are the same as the horizontal coordinates of the first sub-block and vertical.
  • the motion vector of a sub-block with a coordinate distance of Q and the coordinates of its center point constitute a 6-parameter affine motion model used to derive the motion vector of the control point of the current affine decoding block, where P is smaller than the adjacent affine decoding
  • P is smaller than the adjacent affine decoding
  • P is a power of 2
  • Q is smaller than the height V of the adjacent affine decoding block
  • Q is a power of 2.
  • the adjacent affine decoded block is a 6-parameter affine decoded block
  • two sub-blocks with the horizontal coordinate distance P of the sub-block center point in the adjacent affine decoded block and the same vertical coordinate are obtained.
  • the motion vector of a sub-block with a straight distance of Q and the coordinates of its center point constitute a 6-parameter affine motion model, which is used to derive the motion vector of the control point of the current affine decoding block, where P is smaller than the adjacent affine
  • Q is smaller than the height V of the adjacent affine decoded block
  • Q is a power of 2.
  • the parameter types of adjacent affine decoding blocks are not distinguished, and two sub-blocks with horizontal coordinate distance P and the same vertical coordinates (such as respectively (Referred to as the first sub-block and the second sub-block), and the coordinates of their center points, and then obtain the center point of the sub-block in the adjacent affine decoding block with the same horizontal coordinate and vertical distance from the first sub-block
  • the motion vector of a sub-block of Q and the coordinates of its center point constitute a 6-parameter affine motion model used to derive the motion vector of the control point of the current affine decoding block, where P is smaller than that of the adjacent affine decoding block.
  • the width U, and P is a power of 2
  • Q is smaller than the height V of the adjacent affine decoding block
  • Q is a power of 2.
  • the distance between the center points of the two sub-blocks used in the embodiment of the present invention is a power of two, which is conducive to being implemented by shifting when performing motion vector derivation, thereby reducing implementation complexity. .
  • the position of the center point of the subblock used in each of the above examples is for ease of description.
  • the coordinate position of the subblock used for the adjacent affine decoding block may be referred to as the adjacent affine decoding block for short
  • the position of the preset subblock needs to be consistent with the position used in the calculation of the motion vector of the subblock in the codec (that is, the subblock of the adjacent affine decoding block uses the motion vector of the pixel at the preset position in the subblock) Represents the motion vectors of all pixels in the sub-block). Therefore, the preset sub-block positions may be various.
  • the preset sub-block position is the position of the upper-left pixel point in the sub-block of the adjacent affine decoding block, that is, the upper-left pixel point is used to calculate the motion vector of the sub-block during encoding and decoding.
  • the coordinates of the top-left pixel of the sub-block should also be used.
  • the preset sub-block position is the position of a pixel point closest to the geometric center position in the sub-block of the adjacent affine decoding block.
  • the preset sub-block position is the upper right of the sub-block in the adjacent affine decoding block. The position of the corner pixels, and so on.
  • the use conditions of the affine decoding block may be restricted, so that adjacent affine decoding blocks can be divided into at least 2 sub-blocks in the horizontal direction and at least 2 sub-blocks in the vertical direction.
  • the size of the sub-block is MxN
  • M is an integer such as 4, 8, 16, and N is an integer such as 4, 8, 16, and so
  • the allowable size of the affine decoding block is width W ⁇ 2M and height H ⁇ 2N .
  • the neighboring affine decoding block is a 4-parameter affine decoding block, as shown in FIG. 10, it is assumed that the coordinates of the upper left vertex of the neighboring affine decoding block of the current block are (x4, y4 ), The width is U, the height is V, and the divided subblock size is MxN (as shown in Figure 10, the subblock size of the adjacent affine decoding block is 4x4), then the position (x4 + M / 2, y4 + N / 2) motion vector (vx4, vy4) and position (x4 + M / 2 + P, y4 + N / 2) motion vector (vx5, vy5) form a 4-parameter affine motion model.
  • the formula (28) is used to calculate and obtain the motion vector (vx1, vy1) of the upper right control point (x1, y1) of the current affine decoding block.
  • the value of (x1, y1) can be set to (x0 + W, y0), where W is the width of the current block.
  • the motion vector (vx2, vy2) of the lower left control point (x2, y2) of the current affine decoding block is calculated by using formula (29).
  • the value of (x2, y2) can be set to (x0, y0 + H), where H is the height of the current block.
  • the neighboring affine decoding block is a 6-parameter affine decoding block
  • the same is shown in FIG. 10 as an example, and the coordinates of the upper left vertex of the neighboring affine decoding block of the current block are (x4 , y4), the width is U, the height is V, and the divided sub-block size is MxN (as shown in FIG.
  • the sub-block size of the adjacent affine decoding block is 4x4), then the position (x4 + M / 2 , y4 + N / 2) motion vector (vx4, vy4), position (x4 + M / 2 + P, y4 + N / 2) motion vector (vx5, vy5), and position (x4 + M / 2, y4 + N / 2 + Q) motion vectors (vx6, vy6) form a 6-parameter affine motion model.
  • the following vector (30) is used to calculate and obtain the motion vector (vx0, vy0) of the upper left control point (x0, y0) of the current affine decoding block:
  • the motion vector (vx1, vy1) of the upper right control point (x1, y1) of the current affine decoding block is calculated by using formula (31).
  • the value of (x1, y1) can be set to (x0 + W, y0), where W is the width of the current block.
  • the motion vector (vx2, vy2) of the lower left control point (x2, y2) of the current affine decoding block is calculated by using formula (32).
  • the value of (x2, y2) can be set to (x0, y0 + H), where H is the height of the current block.
  • the method in the embodiment of the present invention may also be applied to all adjacent affine decoding blocks without limitation. That is, the motion vectors of three sub-blocks are used to form a 6-parameter affine motion model for derivation.
  • the width U and height V of the codec block are usually powers of 2
  • the value of P can be U / 2
  • the value of Q can be V / 2.
  • U is 8, 16, 32, 64, 128, etc.
  • P is 4, 8, 16, 32, 64, etc .
  • V is 8, 16, 32, 64, 128, etc.
  • Q is 4, 8 respectively. , 16, 32, 64, etc.
  • the motion vector of the control point of the current affine decoding block can be calculated according to the following formula:
  • vx0 Round (mvScaleHor + dHorX * (x0–x4–M / 2) + dHorY * (y0–y4–N / 2))
  • vy0 Round (mvScaleVer + dVerX * (x0–x4–M / 2) + dVerY * (y0–y4–N / 2))
  • vx1 Round (mvScaleHor + dHorX * (x1–x4–M / 2) + dHorY * (y1–y4–N / 2))
  • vy1 Round (mvScaleVer + dVerX * (x1–x4–M / 2) + dVerY * (y1–y4–N / 2))
  • vx2 Round (mvScaleHor + dHorX * (x2–x4–M / 2) + dHorY * (y2–y4–N / 2))
  • vy2 Round (mvScaleVer + dVerX * (x2–x4–M / 2) + dVerY * (y2–y4–N / 2))
  • the adjacent affine decoding block is located above the CTU of the current affine decoding block, in order to reduce the memory read, two sub-locations of the adjacent affine decoding block located at the bottom of the CTU may be obtained.
  • the motion vector of the block is derived.
  • the position (x4 + M / 2, y4 + V– N / 2) motion vector (vx4, vy4) and position (x4 + M / 2 + P, y4 + V–N / 2) motion vector (vx5, vy5) form a 4-parameter affine motion model.
  • the methods in the embodiments of the present invention may also be applied to a case where the adjacent affine decoding block is a 4-parameter affine decoding block without limitation. That is, if the adjacent affine decoding block is a 4-parameter affine decoding block, the motion vectors of the two sub-blocks whose distance between the lowermost center points are P are used for derivation.
  • the neighboring affine decoding block located at the far right of the CTU may be obtained.
  • the motion vectors of the two sub-blocks are derived.
  • the following vector (36) is used to calculate and obtain the motion vector (vx0, vy0) of the upper left control point (x0, y0) of the current affine decoding block:
  • the methods in the embodiments of the present invention may also be applied to a case where the adjacent affine decoding block is a 4-parameter affine decoding block without limitation. That is, if the adjacent affine decoding block is a 4-parameter affine decoding block, the motion vectors of two sub-blocks whose distance between the rightmost center points are Q are used for derivation.
  • the adjacent affine decoding block is located above the current CTU affine decoding block, and the adjacent affine decoding block is a 6-parameter affine decoding block, in order to reduce the memory read, you can The motion vectors of the two sub-blocks located at the bottom of the CTU of the adjacent affine decoding block and the motion vectors of one of the upper sub-blocks are obtained for derivation.
  • the position (x4 + M / 2, y4 + V– N / 2) motion vector (vx4, vy4), position (x4 + M / 2 + P, y4 + V--N / 2) motion vector (vx5, vy5), position (x4 + M / 2, y4 + V–N / 2–Q) motion vectors (vx6, vy6) form a 6-parameter affine motion model.
  • the methods in the embodiments of the present invention may also be applied to a case where the adjacent affine decoding block is a 6-parameter affine decoding block without limitation. That is, if the neighboring affine decoding block is a 6-parameter affine decoding block, the motion vectors of the two sub-blocks with a distance P of the bottom center point and the sub-blocks with a vertical distance Q from the bottom-most sub-block are used. The motion vector is derived.
  • the method in the embodiment of the present invention may also be applied to all adjacent affine decoding blocks without limitation. That is, the motion vectors of the sub-blocks with a distance P of the bottom two center points and the motion vectors of the sub-blocks with a vertical distance Q from the bottom-most sub-block are used for derivation.
  • the adjacent affine decoding block is located at the left CTU of the current affine decoding block, and the adjacent affine decoding block is a 6-parameter affine decoding block, in order to reduce memory read,
  • the motion vectors of two sub-blocks located at the far right of the CTU of the adjacent affine decoding block and the motion vectors of one left sub-block can be obtained for derivation.
  • the position (x4 + U–M / 2, y4 + N / 2) motion vector (vx4, vy4), position (x4 + U–M / 2, y4 + N / 2 + Q) motion vector (vx5, vy5), position (x4 + U–M / 2– P, y4 + N / 2) motion vector (vx6, vy6) constitutes a 6-parameter affine motion model.
  • the methods in the embodiments of the present invention may also be applied to a case where the adjacent affine decoding block is a 6-parameter affine decoding block without limitation. That is, if the adjacent affine decoding block is a 6-parameter affine decoding block, the motion vectors of the two rightmost sub-blocks with a distance of Q and the sub-blocks with a horizontal distance of P from the rightmost sub-block are used. The motion vector of the block is derived.
  • the method in the embodiment of the present invention may also be applied to all adjacent affine decoding blocks without limitation. That is, the motion vectors of the subblocks with a distance Q of the two rightmost center points and the motion vectors of the subblocks with a horizontal distance P from the rightmost subblock are used for derivation.
  • a motion vector prediction method based on an affine motion model provided by an embodiment of the present invention is further described from the perspective of an encoding end or a decoding end. Referring to FIG. 11, the method includes But not limited to the following steps:
  • Step 701 Obtain a spatial reference block of an image block to be processed.
  • the image block to be processed is obtained by segmenting a video image
  • the spatial domain reference block is a decoded block adjacent to the spatial domain of the image block to be processed.
  • the image block to be processed can also be called the current affine coding block
  • the spatial reference block can also be called the adjacent affine coding block.
  • the image block to be processed can also be called the current affine decoding block.
  • the spatial domain reference block may also be called an adjacent affine decoding block.
  • the image blocks to be processed may be collectively referred to as a current block
  • the spatial reference blocks may be collectively referred to as neighboring blocks.
  • the availability of one or more preset candidate spatial reference positions of the current block may be determined according to a preset order, and then the first available candidate reference block in the preset order is obtained as the Airspace reference block.
  • the candidate reference blocks of the preset spatial location include: adjacent image blocks located directly above, directly to the left, upper right, lower left, and upper left of the image block to be processed.
  • the availability of the candidate reference blocks is sequentially checked in the order of directly adjacent left image blocks, immediately above adjacent image blocks, upper right adjacent image blocks, lower left adjacent image blocks, and upper left adjacent image blocks.
  • Candidate reference block is
  • an adjacent position block around the current block may be traversed in the order of A1 ⁇ B1 ⁇ B0 ⁇ A0 ⁇ B2 in FIG. 7 to find the adjacent block where the adjacent position block is located.
  • whether a candidate reference block is available may be determined according to the following method: when the candidate reference block and the image block to be processed are located in the same image region, and the candidate reference block is obtained based on the affine motion model When a motion vector is determined, the candidate reference block is determined to be available.
  • Step 702 Determine two or more preset sub-block positions in the airspace reference block.
  • two or more sub-blocks in the spatial domain reference block may be determined, and each sub-block has a corresponding preset sub-block position, and the preset sub-block position and the motion of the sub-block are calculated in encoding and decoding.
  • the positions used in the vector are the same, that is, the sub-blocks of adjacent affine decoding blocks use the motion vectors of pixels at preset positions in the sub-block to represent the motion vectors of all pixels in the sub-block.
  • the motion vector can be used for subsequent motion compensation to achieve prediction of the sub-block where the pixel at the preset position is located.
  • the preset sub-block position may be the position of the upper-left pixel point in the sub-block; or the position of the geometric center of the sub-block, or the position of a pixel point closest to the geometric center position in the sub-block; or The position of the upper-right pixel in the block, and so on.
  • two sub-blocks in the spatial domain reference block may be determined, and a distance between two preset sub-block positions corresponding to the two sub-blocks is S, S is a power of K, and K is a non-negative integer, This is conducive to subsequent motion vector derivation, which can be implemented by means of shift, thereby reducing the complexity of implementation.
  • the plurality of preset sub-block positions of the spatial reference block include a first preset position (x4 + M / 2, y4 + N / 2) and a second preset position (x4 + M / 2 + P, y4 + N / 2), where x4 is the abscissa of the position of the upper-left pixel in the spatial reference block, and y4 is the spatial reference
  • M is the width of the sub-block
  • N is the height of the sub-block
  • P is the power of K
  • 2 is a non-negative integer
  • K is less than U
  • U is the width of the spatial reference block.
  • the plurality of preset sub-block positions include a first preset position (x4 + M / 2, y4 + N / 2) and The third preset position (x4 + M / 2, y4 + N / 2 + Q), where x4 is the abscissa of the position of the upper-left pixel in the spatial reference block, and y4 is the upper-left pixel in the spatial reference block
  • x4 is the abscissa of the position of the upper-left pixel in the spatial reference block
  • y4 is the upper-left pixel in the spatial reference block
  • M is the width of the sub-block
  • N is the height of the sub-block
  • Q is the power of R
  • R is a non-negative integer
  • Q is less than V
  • V is the height of the spatial reference block.
  • the plurality of preset sub-block positions include a first preset position (x4 + M / 2, y4 + N / 2), A second preset position (x4 + M / 2 + P, y4 + N / 2) and a third preset position (x4 + M / 2, y4 + N / 2 + Q), where x4 is the airspace reference
  • x4 is the airspace reference
  • y4 is the ordinate of the position of the upper-left pixel in the spatial reference block
  • M is the width of the sub-block
  • N is the height of the sub-block
  • P is the power of K
  • Q Power of R
  • K and R are non-negative integers
  • P is less than U
  • Q is less than V
  • U is the width of the spatial domain reference block
  • V is the height of the spatial domain reference block.
  • the spatial reference block is located directly above the image block to be processed At the top left, or the top right, at least two of the sub-blocks corresponding to the plurality of preset sub-block positions are adjacent to the upper edge of the current block.
  • CTU coding tree unit
  • the straight line where the left edge of the current block is located coincides with the straight line where the left edge of the coding tree unit (CTU) where the current block is located, and the spatial reference block is located directly to the left of the current block and to the upper left Or at the lower left, at least two of the sub-blocks corresponding to the plurality of preset sub-block positions are adjacent to the left edge of the current block.
  • CTU coding tree unit
  • Step 703 Interpolate and calculate the motion vector corresponding to the preset pixel position of the image block to be processed according to the motion vector corresponding to the preset sub-block position.
  • an improved inherited control point motion vector prediction method is used to determine candidate control point motion vectors of the current block, that is, at least two sub-blocks of adjacent affine coding blocks (or adjacent affine decoding blocks) are used.
  • the motion vector of the current block is calculated by interpolation to obtain the motion vector of the preset pixel position of the current block.
  • the preset pixel position is the control point of the current block.
  • the affine motion model of the current block is a 4-parameter affine motion Model
  • the control points of the current block can be the upper left pixel and the upper right pixel in the sub-block.
  • the affine motion model of the current block is a 6-parameter affine motion model
  • the control points of the current block may be the upper left pixel point, the upper right pixel point, and the lower left pixel point in the sub-block, and so on.
  • Step 704 Interpolate and calculate motion vectors corresponding to multiple sub-block positions in the image block to be processed according to the motion vectors corresponding to the preset pixel point positions.
  • a preset position pixel in the motion compensation unit can be used Point motion information to represent the motion information of all pixels in the motion compensation unit. Assuming the size of the motion compensation unit is MxN, the preset position pixels can be the center point of the motion compensation unit (M / 2, N / 2), the upper left pixel (0, 0), and the upper right pixel (M-1,0 ), Or pixels at other locations.
  • the motion vector value of each sub-block in the current block can be obtained, and subsequent motion compensation can be performed according to the motion vector value of the sub-block to obtain the sub-block.
  • subsequent motion compensation can be performed according to the motion vector value of the sub-block to obtain the sub-block.
  • the embodiment of the present invention adopts an improved inherited control point motion vector prediction method.
  • the improved inherited control point motion vector prediction method does not need to use the motion vectors of control points of adjacent blocks, but uses adjacent blocks.
  • the motion vectors of at least two sub-blocks are used to derive the motion vectors of the control points of the current block, and then the motion vectors of each sub-block of the current block are derived based on the motion vectors of the control points, and prediction of the current block is achieved through motion compensation.
  • the motion vector of the control point of the current block does not need to be stored subsequently, that is, the motion vector of the control point of the current block is only used to derive the motion vector of the sub-block of the current decoding block, and is not used to predict the motion vector of the neighboring block. Therefore, the solution of the present invention only needs to save the motion vectors of the sub-blocks, and uses the motion vectors of the sub-blocks for motion compensation, while solving the problem of storing the motion vectors, and avoiding that the sub-block where the control point is located is inconsistent with other sub-blocks
  • the motion vector is used for motion compensation, which improves the accuracy of prediction.
  • the motion vector prediction method based on the affine motion model provided by the embodiment of the present invention is further described below from the perspective of a decoding end. Referring to FIG. 12, the method includes, but is not limited to, The following steps:
  • Step 801 Parse the bitstream to determine the inter prediction mode of the current block.
  • the code stream may be parsed based on the syntax structure shown in Table 1 to determine the inter prediction mode of the current block.
  • steps 802a to 806a are performed.
  • Step 802a Construct a candidate motion vector list corresponding to the AMVP mode based on the affine motion model.
  • the candidate control point motion vector of the current block can be obtained and added to the candidate motion vector corresponding to the AMVP mode. List.
  • the improved inherited control point motion vector prediction method uses the motion vectors of at least two sub-blocks of adjacent affine decoding blocks to determine the candidate control points of the current block in the process of determining the candidate control point motion vector of the current block.
  • the motion vector prediction value (candidate motion vector tuple / triple / quad) is added to the candidate motion vector list.
  • the candidate motion vector list may include a list of two tuples, and the list of two tuples includes one or more tuples used to construct the 4-parameter affine motion model.
  • the candidate motion vector list may include a triple list, and the triple list includes one or more triples for constructing a 6-parameter affine motion model.
  • the candidate motion vector list may include a quaternion list, and the quaternion list includes one or more quaternions used to construct the 8-parameter bilinear model.
  • the candidate motion vector tuple / triple / quaternion list can be pruned and sorted according to a specific rule, and it can be truncated or filled to a specific number.
  • the adjacent position blocks around the current block can be traversed in the order of A1 ⁇ B1 ⁇ B0 ⁇ A0 ⁇ B2 in FIG. 7 to find adjacent position blocks.
  • the affine decoded block uses the motion vectors of at least two sub-blocks of adjacent affine decoded blocks to construct the affine motion model, and then derives the candidate control point motion vector of the current block (candidate motion vector binary / ternary Group / quad), added to the candidate motion vector list.
  • search orders may also be applied to the embodiments of the present invention, and details are not described herein.
  • control point motion vector prediction method for the construction of the AMVP mode based on the affine motion model is also described in detail in the foregoing 4. For the sake of brevity of the description, it will not be repeated here.
  • Step 803a Parse the code stream to determine the optimal control point motion vector prediction value.
  • the index number of the candidate motion vector list is obtained by analyzing the code stream, and the optimal control point motion vector prediction value is determined from the candidate motion vector list constructed in the foregoing step 602a according to the index number.
  • the affine motion model used by the current decoding block is a 4-parameter affine motion model (MotionModelIdc is 1)
  • the index number is obtained by analysis.
  • the index number is mvp_l0_flag or mvp_l1_flag
  • the candidate motion vector list is obtained from the index
  • the optimal motion vector prediction value of 2 control points is determined in.
  • the affine motion model used by the current decoding block is a 6-parameter affine motion model (MotionModelIdc is 2)
  • the index number is obtained by analysis, and the optimal motion of the three control points is determined from the candidate motion vector list according to the index number.
  • Vector prediction is a 6-parameter affine motion model (MotionModelIdc is 2)
  • the affine motion model used in the current decoding block is an 8-parameter bilinear model
  • an index number is obtained through analysis, and the optimal motion vector prediction value of 4 control points is determined from the candidate motion vector list according to the index number.
  • Step 804a Parse the code stream and determine the motion vector of the control point.
  • the motion vector difference of the control point is obtained by analyzing the code stream, and then the motion vector of the control point is obtained according to the motion vector difference of the control point and the optimal control point motion vector prediction value determined in the foregoing step 803a.
  • the affine motion model used in the current decoding block is a 4-parameter affine motion model (MotionModelIdc is 1).
  • the forward prediction is taken as an example.
  • the difference between the motion vector of the two control points is mvd_coding (x0, y0,0,0 ) And mvd_coding (x0, y0,0,1).
  • the motion vector difference values of the two control points of the current block are obtained by decoding from the code stream.
  • the motion vector difference values of the upper left position control point and the upper right position control point can be obtained from the code stream by decoding.
  • the motion vector difference value and the motion vector prediction value of each control point are respectively added to obtain the motion vector value of the control point, that is, the motion vector values of the upper left position control point and the upper right position control point of the current block are obtained.
  • the current decoding block affine motion model is a 6-parameter affine motion model (MotionModelIdc is 2), and the forward prediction is taken as an example.
  • the motion vector differences of the three control points are mvd_coding (x0, y0,0,0) and mvd_coding (x0, y0,0,1), mvd_coding (x0, y0,0,2).
  • the motion vector differences of the three control points of the current block are obtained by decoding from the code stream. For example, the motion vector differences of the upper left control point, the upper right control point, and the lower left control point are obtained from the code stream by decoding.
  • the motion vector difference value and the motion vector prediction value of each control point are respectively added to obtain the motion vector value of the control point, that is, the motion vector values of the upper left control point, the upper right control point, and the lower left control point of the current block are obtained.
  • embodiments of the present invention may also be other affine motion models and other control point positions, and details are not described herein.
  • Step 805a Obtain a motion vector value of each sub-block in the current block according to the motion vector of the control point and the affine motion model adopted by the current block.
  • the preset position pixels in the motion compensation unit can be used Point motion information to represent the motion information of all pixels in the motion compensation unit. Assuming the size of the motion compensation unit is MxN, the preset position pixels can be the center point of the motion compensation unit (M / 2, N / 2), the upper left pixel (0, 0), and the upper right pixel (M-1,0 ), Or pixels at other locations.
  • FIG. 13 shows the current affine decoding block and the motion compensation unit (sub-block). Each small box in the figure represents a motion compensation unit.
  • V0 represents the motion vector of the upper left control point of the current affine decoding block
  • V1 represents the motion vector of the upper right control point of the current affine decoding block
  • V2 represents the motion vector of the lower left control point of the current affine decoding block.
  • the coordinates of the center point of the motion compensation unit relative to the top left pixel of the current affine decoding block can be calculated using the following formula (45):
  • (x (i, j) , y (i, j) ) Represents the coordinates of the center point of the (i, j) th motion compensation unit relative to the upper left control point pixel of the current affine decoding block.
  • the affine motion model used in the current affine decoding block is a 6-parameter affine motion model
  • substituting (x (i, j) , y (i, j) ) into the 6-parameter affine motion model formula (46) obtain each Motion vectors of the center points of each motion compensation unit as the motion vectors (vx (i, j) , vy (i, j) ) of all pixels in the motion compensation unit:
  • the affine motion model used by the current affine decoding block is a 4 affine motion model
  • substitute (x (i, j) , y (i, j) ) into the 4-parameter affine motion model formula (47) and obtain each
  • the motion vector of the center point of the motion compensation unit is used as the motion vector of all pixels in the motion compensation unit (vx (i, j) , vy (i, j) ):
  • Step 806a For each sub-block, perform motion compensation according to the determined motion vector value of the sub-block to obtain a pixel prediction value of the sub-block.
  • Step 802b Construct a motion information candidate list based on the merge mode of the affine motion model.
  • candidate control point motion vectors of the current block can be obtained and added to the candidate motion vectors corresponding to the merge mode. List.
  • the improved inherited control point motion vector prediction method uses the motion vectors of at least two sub-blocks of adjacent affine decoding blocks to determine the candidate control points of the current block in the process of determining the candidate control point motion vector of the current block.
  • Motion vectors (candidate motion vector tuples / triads / quads) to join the candidate motion vector list.
  • the motion information candidate list can be pruned and sorted according to a specific rule, and it can be truncated or filled to a specific number.
  • FIG. 8 For example, taking FIG. 8 as an example, according to the sequence of A1 ⁇ B1 ⁇ B0 ⁇ A0 ⁇ B2, it can traverse the adjacent position blocks around the current block, find the affine coding block where the adjacent position block is located, and use adjacent affine decoding blocks.
  • the affine motion model is constructed by the motion vectors of at least two sub-blocks, and then the candidate control point motion vectors (candidate motion vector tuples / triads / quads) of the current block are derived and added to the candidate motion vector list. It should be noted that other search orders may also be applied to the embodiments of the present invention, and details are not described herein.
  • the candidate control point motion information is added to the candidate list; otherwise, the motion information in the candidate motion vector list is sequentially traversed in order to check the candidate motion vector list. Whether there is the same motion information as the candidate control point motion information. If the candidate motion vector list does not have the same motion information as the candidate control point motion information, the candidate control point motion information is added to the candidate motion vector list.
  • judging whether the two candidate motion information are the same requires judging whether their forward and backward reference frames and the horizontal and vertical components of each forward and backward motion vector are the same. Only when all the above elements are different, the two motion information are considered different.
  • MaxAffineNumMrgCand is a positive integer, such as 1, 2, 3, 4, 5, etc.
  • control point motion vector prediction method based on the construction of the Merge mode based on the affine motion model is also described in detail in the foregoing 4). For the sake of brevity of the description, it will not be repeated here.
  • Step S803b Parse the code stream to determine the optimal control point motion information.
  • the index number of the candidate motion vector list is obtained by analyzing the code stream, and the optimal control point motion information is determined from the candidate motion vector list constructed in the foregoing step 802b according to the index number.
  • Step 804b Obtain a motion vector value of each sub-block in the current block according to the optimal control point motion information and the affine motion model adopted by the current decoding block.
  • Step 804b Obtain a motion vector value of each sub-block in the current block according to the optimal control point motion information and the affine motion model adopted by the current decoding block.
  • Step 805b For each sub-block, perform motion compensation according to the determined motion vector value of the sub-block to obtain a pixel prediction value of the sub-block.
  • an improved inherited control point motion vector prediction method is used. Because the improved inherited control point motion vector prediction method does not need to use the motion vector of the control point of the adjacent block, but The motion vectors of at least two sub-blocks of adjacent affine decoding blocks are used. After the derivation of the sub-block motion vectors of each affine decoding block is completed, the motion vectors of the control points need not be stored, that is, the control points of the current decoding block are The motion vector is only used for deriving the motion vector of the sub-block of the current decoding block, and is not used for the motion vector prediction of the neighboring block. Therefore, the solution of the present invention only needs to save the motion vectors of the sub-blocks, and all use the motion vectors of the sub-blocks for motion compensation, while solving the problem of motion vector storage, and also improving the accuracy of prediction.
  • the motion vector prediction method based on the affine motion model according to the embodiment of the present invention is further described from the perspective of the encoding end. Referring to FIG. 14, the method includes but is not limited to The following steps:
  • Step 901 Determine an inter prediction mode of the current block.
  • multiple inter prediction modes may also be preset.
  • the multiple intra prediction modes include, for example, the AMVP mode based on the affine motion model described above and Based on the merge mode of the affine motion model, the encoder traverses the multiple inter prediction modes to determine the inter prediction mode that is optimal for the current block prediction.
  • only one inter prediction mode may be preset. In this case, the encoding end directly determines that the current inter prediction mode is currently used.
  • the inter-prediction mode is AMVP mode based on affine motion model or merge mode based on affine motion model.
  • steps 902a to 904a are performed subsequently.
  • steps 902b to 904b are performed subsequently.
  • Step 902a Construct a candidate motion vector list corresponding to the AMVP mode based on the affine motion model.
  • the candidate control point motion vector prediction value of the current block (such as the candidate motion vector binary group) may be obtained based on the improved inherited control point motion vector prediction method and / or the constructed control point motion vector prediction method. / Triple / quad) to join the candidate motion vector list corresponding to the AMVP mode.
  • step 802a For specific implementation of this step, reference may be made to the description of step 802a in the foregoing embodiment, and details are not described herein again.
  • Step 903a Determine the optimal control point motion vector prediction value according to the rate distortion cost.
  • the encoding end may use the control point motion vector prediction value in the candidate motion vector list (such as the candidate motion vector binary / triad / quaternary), using formula (3) or (5) or ( 7) Obtain the motion vector of each sub-motion compensation unit in the current block, and then obtain the pixel value of the corresponding position in the reference frame pointed by the motion vector of each sub-motion compensation unit, as its predicted value, perform the motion using the affine motion model make up. Calculate the average of the difference between the original value and the predicted value of each pixel in the current coding block, select the control point motion vector prediction value corresponding to the smallest average value as the optimal control point motion vector prediction value, and use it as the current block Motion vector predictions for 2 or 3 or 4 control points.
  • the candidate motion vector list such as the candidate motion vector binary / triad / quaternary
  • Step 904a encode the index value, the motion vector difference of the control point, and the indication information of the inter prediction mode into the code stream.
  • the decoder can use the optimal control point motion vector prediction value as the search starting point to perform a motion search within a certain search range to obtain control point motion vectors (CPMV) and calculate the control point motion vector. And the control point motion vector prediction (CPMVD). Then, the encoding end encodes the index value indicating the position of the control point motion vector prediction in the candidate motion vector list and the CPMVD code into the code. In addition, the indication information of the inter prediction mode can also be coded into a code stream for subsequent transmission to the decoding end.
  • CPMV control point motion vectors
  • the encoding end encodes the index value indicating the position of the control point motion vector prediction in the candidate motion vector list and the CPMVD code into the code.
  • the indication information of the inter prediction mode can also be coded into a code stream for subsequent transmission to the decoding end.
  • Step 902b Construct a candidate motion vector list corresponding to the Merge mode based on the affine motion model.
  • the candidate control point motion vector prediction value of the current block (such as the candidate motion vector binary group) may be obtained based on the improved inherited control point motion vector prediction method and / or the constructed control point motion vector prediction method. / Triple / quad) to join the candidate motion vector list corresponding to the Merge mode.
  • step 802b For specific implementation of this step, reference may be made to the description of step 802b in the foregoing embodiment, and details are not described herein again.
  • Step 903b Determine the optimal control point motion information according to the rate distortion cost.
  • the encoding end may use the control point motion vector (such as the candidate motion vector binary / triple / quad) in the candidate motion vector list by formula (3) or (5) or (7)
  • the motion vector of each sub motion compensation unit in the current coding block is obtained, and then the pixel value of the position in the reference frame pointed to by the motion vector of each sub motion compensation unit is used as its prediction value to perform affine motion compensation.
  • the optimal control The point motion vector is the motion vector of 2 or 3 or 4 control points of the current coding block.
  • Step 904b encode the index value and the indication information of the inter prediction mode into the code stream.
  • the decoding end may encode an index value indicating the position of the control point motion vector in the candidate list into the code stream, and the indication information of the inter prediction mode is coded into the code stream for subsequent transmission to the decoding end.
  • the above embodiment only describes the process of encoding and code stream sending at the encoding end. According to the foregoing description, those skilled in the art understand that the encoding end can also implement other methods described in the embodiments of the present invention in other links. For example, in the prediction of the current block at the encoding end, the specific implementation of the reconstruction process of the current block can refer to the related method described above at the decoding end (as shown in the embodiment of FIG. 12), which will not be repeated here.
  • an improved method of predicting a control point motion vector is adopted. Since the improved method of predicting a control point motion vector does not need to use a motion vector of a control point of an adjacent affine coding block Instead, the motion vectors of at least two sub-blocks of adjacent affine coding blocks are used to derive the control point candidate motion vectors of the current block based on the motion vectors of the at least two sub-blocks and establish a list to obtain the optimal control point candidate motion vector. And send its corresponding index value in the list to the decoder.
  • the motion vector of the control point does not need to be stored, that is, the motion vector of the control point of the current coding block is only used for the motion vector of the sub-block of the current coding block. It is deduced that subsequent motion vector prediction is not used for neighboring blocks. Therefore, the solution of the present invention only needs to save the motion vectors of the sub-blocks, and all use the motion vectors of the sub-blocks for motion compensation, while solving the problem of storing the motion vectors, the accuracy of prediction is also improved.
  • an embodiment of the present invention further provides a device 1000.
  • the device 1000 includes a reference block acquisition module 1001, a sub-block determination module 1002, a first calculation module 1003, and a second calculation module 1004. :
  • a sub-block determining module 1002 configured to determine positions of multiple preset sub-blocks in the airspace reference block
  • a first calculation module 1003 configured to interpolate and calculate a motion vector corresponding to a preset pixel position of the image block to be processed according to a motion vector corresponding to the preset sub-block position;
  • a second calculation module 1004 is configured to interpolate and calculate a motion vector corresponding to a plurality of sub-block positions in the image block to be processed according to a motion vector corresponding to the preset pixel point position.
  • the reference block obtaining module 1001 is specifically configured to determine the availability of candidate reference blocks of one or more preset spatial domain positions of the image block to be processed according to a preset order; Let the first available candidate reference block in the sequence be used as the airspace reference block.
  • the candidate reference block and the image block to be processed are located in the same image region, and the candidate reference block obtains a motion vector based on the affine motion model, it is determined that the candidate reference block is available.
  • the candidate reference blocks of the preset spatial location include: adjacent image blocks located directly above, directly to the left, upper right, lower left, and upper left of the image block to be processed;
  • the reference block acquisition module 1001 is specifically configured to: sequentially check the availability of the candidate reference blocks in the order of directly adjacent left image blocks, immediately above adjacent image blocks, upper right adjacent image blocks, lower left adjacent image blocks, and upper left adjacent image blocks. Until the first available candidate reference block is determined.
  • the position of the sub-block includes: a position of an upper-left pixel point in the sub-block; or a position of a geometric center of the sub-block, or a position closest to the geometric center in the sub-block The position of one pixel.
  • a distance between two preset sub-block positions in the plurality of preset sub-block positions is S, S is a power of K, and K is a non-negative integer.
  • the affine motion model is a 4-parameter affine motion model
  • the plurality of preset sub-block positions include a first preset position (x4 + M / 2, y4 + N / 2) and The second preset position (x4 + M / 2 + P, y4 + N / 2), where x4 is the abscissa of the position of the upper-left pixel in the spatial reference block, and y4 is the upper-left pixel in the spatial reference block
  • M is the width of the sub-block
  • N is the height of the sub-block
  • P is the power of K
  • K is a non-negative integer
  • K is less than U
  • U is the width of the spatial reference block.
  • the affine motion model is a 4-parameter affine motion model
  • the plurality of preset sub-block positions include a first preset position (x4 + M / 2, y4 + N / 2) and The third preset position (x4 + M / 2, y4 + N / 2 + Q), where x4 is the abscissa of the position of the upper-left pixel in the spatial reference block, and y4 is the upper-left pixel in the spatial reference block
  • M is the width of the sub-block
  • N is the height of the sub-block
  • Q is the power of R
  • R is a non-negative integer
  • Q is less than V
  • V is the height of the spatial reference block.
  • the preset pixel position includes an upper left pixel position in the image block to be processed
  • the first calculation module 1003 is specifically configured to calculate the image block to be processed according to the following formula Motion vector corresponding to the preset pixel position:
  • vx 0 is the horizontal component of the motion vector corresponding to the position of the upper left pixel point in the image block to be processed
  • vy 0 is the vertical component of the motion vector corresponding to the position of the pixel point in the upper left corner in the image block to be processed
  • vx 1 is the horizontal component of the motion vector corresponding to the pixel position of the upper right corner in the image block to be processed
  • vy 1 is the vertical component of the motion vector corresponding to the pixel position of the upper right corner in the image block to be processed
  • vx 2 is The horizontal component of the motion vector corresponding to the position of the bottom left pixel point in the image block to be processed is described
  • vy 2 is the vertical component of the motion vector corresponding to the position of the bottom left pixel point in the image block to be processed
  • vx 4 is the first The horizontal component of the motion vector corresponding to the preset position
  • vy 4 is the vertical component of the motion vector corresponding to the first preset position
  • vx 5
  • the preset pixel position includes an upper left pixel position in the image block to be processed and an upper right pixel position in the image block to be processed.
  • the second calculation module 1004 specifically uses Therefore, the motion vectors corresponding to the positions of multiple sub-blocks in the image block to be processed are calculated according to the following formula:
  • vx is the horizontal component of a corresponding motion vector at (x, y) of the plurality of sub-block positions
  • vy is at (x , y) A vertical component of a corresponding motion vector.
  • the affine motion model is a 6-parameter affine motion model
  • the plurality of preset sub-block positions include a first preset position (x4 + M / 2, y4 + N / 2), A second preset position (x4 + M / 2 + P, y4 + N / 2) and a third preset position (x4 + M / 2, y4 + N / 2 + Q), where x4 is the airspace reference
  • y4 is the ordinate of the position of the upper-left pixel in the spatial reference block
  • M is the width of the sub-block
  • N is the height of the sub-block
  • P is the power of K
  • Q is 2 Power of R
  • K and R are non-negative integers
  • P is less than U
  • Q is less than V
  • U is the width of the spatial domain reference block
  • V is the height of the spatial domain reference block.
  • the preset pixel position includes an upper left pixel position in the image block to be processed, an upper right pixel position in the image block to be processed, and a lower left corner in the image block to be processed.
  • Pixel position, the first calculation module 1003 is specifically configured to calculate a motion vector corresponding to a preset pixel position of the image block to be processed according to the following formula:
  • vx 0 is the horizontal component of the motion vector corresponding to the position of the upper left pixel point in the image block to be processed
  • vy 0 is the vertical component of the motion vector corresponding to the position of the pixel point in the upper left corner in the image block to be processed
  • vx 1 is the horizontal component of the motion vector corresponding to the pixel position of the upper right corner in the image block to be processed
  • vy 1 is the vertical component of the motion vector corresponding to the pixel position of the upper right corner in the image block to be processed
  • vx 2 is The horizontal component of the motion vector corresponding to the position of the bottom left pixel point in the image block to be processed is described
  • vy 2 is the vertical component of the motion vector corresponding to the position of the bottom left pixel point in the image block to be processed
  • vx 4 is the first The horizontal component of the motion vector corresponding to the preset position
  • vy 4 is the vertical component of the motion vector corresponding to the first preset position
  • vx 5
  • the second calculation module 1004 is specifically configured to calculate a motion vector corresponding to multiple sub-block positions in the image block to be processed according to the following formula:
  • W is the width of the image block to be processed
  • H is the height of the image block to be processed
  • vx is the horizontal component of a corresponding motion vector at (x, y) of the plurality of sub-block positions
  • vy Is the vertical component of a corresponding motion vector at (x, y) of the plurality of sub-block positions.
  • the straight line where the upper edge of the image block to be processed is located coincides with the straight line where the upper edge of the coding tree unit CTU where the image block to be processed is located, and the spatial reference block is located at the
  • the image block to be processed is directly above, left above, or right above, at least two of the sub blocks corresponding to the plurality of preset sub block positions are adjacent to the upper edge of the image block to be processed.
  • the spatial reference block is located at the When directly to the left, upper left, or lower left of the image block to be processed, at least two of the sub blocks corresponding to the plurality of preset sub block positions are adjacent to the left edge of the image block to be processed.
  • the motion vectors corresponding to the positions of the multiple sub-blocks are respectively used to predict the motion vectors of the multiple sub-blocks.
  • the reference block obtaining module 1001, the sub-block determining module 1002, the first calculation module 1003, and the second calculation module 1004 may be applied to the inter prediction process at the encoding end or the decoding end. Specifically, at the encoding end, these modules can be applied to the inter prediction unit 244 in the prediction processing unit 260 of the aforementioned encoder 20; at the decoding end, these modules can be applied to the frames in the prediction processing unit 360 of the aforementioned decoder 30 Inter prediction unit 344.
  • a computer-readable medium may include a computer-readable storage medium, which corresponds to a tangible medium such as a data storage medium or a communication medium including any medium that facilitates transfer of a computer program from one place to another, according to a communication protocol, for example.
  • computer-readable media generally may correspond to non-transitory, tangible computer-readable storage media, or communication media such as signals or carrier waves.
  • a data storage medium may be any available medium that can be accessed by one or more computers or one or more processors to retrieve instructions, codes, and / or data structures used to implement the techniques described in this disclosure.
  • 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, disk storage or other magnetic storage devices, flash memory, or may be used to store instructions or data structures Any other media that requires program code and is accessible by the computer.
  • any connection is properly termed a computer-readable medium.
  • a 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, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the medium.
  • 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 compact discs include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), flexible discs and Blu-ray discs, where the discs are usually magnetic The data is reproduced, while the optical disk uses a laser to reproduce the data optically. Combinations of the above should also be included within the scope of computer-readable media.

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Abstract

本申请公开了基于仿射运动模型的运动矢量预测方法以及设备，该方法包括：获取待处理图像块的一个空域参考块；确定所述空域参考块中多个预设子块位置；根据所述预设子块位置对应的运动矢量，插值计算出所述待处理图像块预设像素点位置对应的运动矢量；根据所述预设像素点位置对应的运动矢量，插值计算出所述待处理图像块中多个子块位置对应的运动矢量。实施本申请能够提高编解码中的预测准确性，提升编码效率。

Description

基于仿射运动模型的运动矢量预测方法及设备 技术领域
本发明涉及视频编解码领域，尤其涉及基于仿射运动模型的运动矢量预测方法及设备。
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。即使最新的高效视频编码(High Efficiency video coding，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。
发明内容
本发明实施例提供了基于仿射运动模型的运动矢量预测方法及设备，能够提高视频编解码中预测的准确性，提升编码效率。
第一方面，本发明提供了一种基于仿射运动模型的运动矢量预测方法，从编码端或解码端的角度进行描述，包括：获取待处理图像块的一个空域参考块，其中，待处理图像块为通过对视频图像进行分割而得到的，空域参考块为与所述待处理图像块空域相邻的已解码块。在编码端，待处理图像块为当前仿射编码块，空域参考块为相邻仿射编码块。在解码端，待处理图像块为当前仿射解码块，空域参考块为相邻仿射解码块。为了便于描述，可将待处理图像块统称为当前块，将空域参考块统称为相邻块；然后，确定所述空域参考块中两个或两个以上的子块的预设子块位置，每个子块都有相应的预设子块位置，该预设子块位置与编解码中计算该子块的运动矢量时所采用的位置一致，即相邻仿射解码块的子块采用该子块中预设位置像素点的运动矢量来表示该子块内所有像素点的运动矢量；然后，根据所述两个或两个以上的子块的预设子块位置对应的运动矢量，插值计算出所述待处理图像块的预设像素点位置对应的运动矢量，所述预设像素点位置即为所述待处理图像块的控制点；然后，根据所述预设像素点位置对应的运动矢量组成当前块的仿射运动模型，插值计算出所述待处理图像块中多个子块位置对应的运动矢量。
其中，所述多个子块位置对应的运动矢量分别用于所述多个子块的运动矢量的预测。
可以看到，实施本发明实施例，不需要利用到相邻块控制点的运动矢量，而是采用相邻块至少两个子块的运动矢量，推导当前块的控制点的运动矢量，进而根据控制点的运动矢量推导得到当前块的各个子块的运动矢量。当前块的控制点的运动矢量后续将不需要进 行存储，即当前块的控制点的运动矢量只用于该当前解码块的子块的运动矢量的推导，不用于相邻块的运动矢量预测。因此，本发明方案只需要保存子块的运动矢量，并且均采用子块的运动矢量进行运动补偿，解决运动矢量存储的问题的同时，避免了控制点所在的子块使用了与其他子块不一致的运动矢量进行运动补偿，提高了预测的准确性。
基于第一方面，在可能的实施方式中，可确定所述空域参考块中两个子块，两个子块对应的两个预设子块位置之间的距离为S，S为2的K次幂，K为非负整数，这样有利于后续在进行运动矢量推导时，能够通过移位的方式进行实现，从而降低了实现的复杂度。
基于第一方面，在可能的实施方式中，预设子块位置可以是子块内左上角像素点的位置；或者，子块的几何中心的位置，或者，子块内距离几何中心位置最近的一个像素点的位置；或者子块内右上角像素点的位置，等等。
基于第一方面，在可能的实施方式中，可按照预设顺序确定当前块的一个或多个预设空域位置的候选参考块的可用性，然后，获得在所述预设顺序中第一个可用的候选参考块作为所述空域参考块。其中，所述预设空域位置的候选参考块包括：位于所述待处理图像块正上方、正左方、右上方、左下方和左上方的相邻图像块。比如，按照正左方相邻图像块、正上方相邻图像块、右上方相邻图像块、左下方相邻图像块、左上方相邻图像块的顺序依次检查所述候选参考块的可用性，直到确定所述第一个可用的候选参考块。
具体的，可根据以下方法来确定候选参考块是否可用：当所述候选参考块与所述待处理图像块位于同一图像区域内，并且所述候选参考块基于所述仿射运动模型获得运动矢量时，确定所述候选参考块可用。
基于第一方面，在可能的实施方式中，如果当前块的仿射运动模型为4参数仿射运动模型，那么所述空域参考块的多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)和第二预设位置(x4+M/2+P,y4+N/2)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，P为2的K次幂，K为非负整数，K小于U，U为所述空域参考块的宽度。这样可有利于后续在进行运动矢量推导时，能够通过移位的方式进行实现，降低了实现的复杂度。
基于第一方面，在可能的实施方式中，如果当前块的仿射运动模型为4参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)和第三预设位置(x4+M/2,y4+N/2+Q)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，Q为2的R次幂，R为非负整数，Q小于V，V为所述空域参考块的高度。这样有利于后续在进行运动矢量推导时，能够通过移位的方式进行实现，降低了实现的复杂度。
在一实例中，如果当前块的仿射运动模型为6参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)，第二预设位置(x4+M/2+P,y4+N/2)和第三预设位置(x4+M/2,y4+N/2+Q)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，P为2的K次幂，Q为2的R次幂，K和R为非负整数，P小于U，Q小于V,U为所述空域参考块的宽度,V为所述空域参考块的高度。这样有利于后续在进行运动矢量推导时，能够通过移位的方式进行实现，降低了实现的复杂度。
在又一实例中，如果当前块的上边缘所在的直线和当前块所在的编码树单元(CTU)的上边缘所在的直线重合，且所述空域参考块位于所述待处理图像块的正上方、左上方或右上方时，所述多个预设子块位置对应的子块中的至少两个子块与当前块的上边缘邻接。
基于第一方面，在可能的实施方式中，如果当前块的左边缘所在的直线和当前块所在的编码树单元(CTU)的左边缘所在的直线重合，且所述空域参考块位于当前块的正左方、左上方或左下方时，所述多个预设子块位置对应的子块中的至少两个子块与当前块的左边缘邻接。
基于第一方面，在可能的实施方式中，采用改进的继承的控制点运动矢量预测方法在确定当前块的候选的控制点运动矢量，即采用相邻仿射编码块(或相邻仿射解码块)至少两个子块的运动矢量来，通过插值计算得到当前块的预设像素点位置的运动矢量，预设像素点位置即为当前块的控制点，比如，如果当前块的仿射运动模型为4参数仿射运动模型，那么当前块的控制点可为子块内左上角像素点和右上角像素点。如果当前块的仿射运动模型为6参数仿射运动模型，那么当前块的控制点可为子块内左上角像素点、右上角像素点以及左下角像素点，等等。
基于第一方面，在可能的实施方式中，如果当前块的仿射运动模型为4参数仿射运动模型，那么当前块的控制点可包括所述待处理图像块内左上角像素点位置，所述待处理图像块内右上角像素点位置和所述待处理图像块内左下角像素点位置中的至少两个，所述根据所述预设子块位置对应的运动矢量，插值计算出所述待处理图像块预设像素点位置对应的运动矢量，包括根据如下公式计算出所述待处理图像块预设像素点位置对应的运动矢量：
Figure PCTCN2019091364-appb-000001
Figure PCTCN2019091364-appb-000002
Figure PCTCN2019091364-appb-000003
其中，vx 0为所述待处理图像块内左上角像素点位置对应的运动矢量的水平分量，vy 0为所述待处理图像块内左上角像素点位置对应的运动矢量的竖直分量，vx 1为所述待处理图像块内右上角像素点位置对应的运动矢量的水平分量，vy 1为所述待处理图像块内右上角像素点位置对应的运动矢量的竖直分量，vx 2为所述待处理图像块内左下角像素点位置对应的运动矢量的水平分量，vy 2为所述待处理图像块内左下角像素点位置对应的运动矢量的竖直分量，vx 4为所述第一预设位置对应的运动矢量的水平分量，vy 4为所述第一预设位置对应的运动矢量的竖直分量，vx 5为所述第二预设位置对应的运动矢量的水平分量，vy 5为所述第二预设位置对应的运动矢量的竖直分量，x 0为所述待处理图像块内左上角像素点位置横坐标，y 0为所述待处理图像块内左上角像素点位置纵坐标，x 1为所述待处理图像块内右上角像素点 位置横坐标，y 1为所述待处理图像块内右上角像素点位置纵坐标，x 2为所述待处理图像块内左下角像素点位置横坐标，y 2为所述待处理图像块内左下角像素点位置纵坐标。
基于第一方面，在可能的实施方式中，如果当前块的仿射运动模型为6参数仿射运动模型，那么当前块的控制点可包括所述待处理图像块内左上角像素点位置，所述待处理图像块内右上角像素点位置和所述待处理图像块内左下角像素点位置，所述根据所述预设子块位置对应的运动矢量，插值计算出所述待处理图像块预设像素点位置对应的运动矢量，包括根据如下公式计算出所述待处理图像块预设像素点位置对应的运动矢量：
Figure PCTCN2019091364-appb-000004
Figure PCTCN2019091364-appb-000005
Figure PCTCN2019091364-appb-000006
其中，vx 0为所述待处理图像块内左上角像素点位置对应的运动矢量的水平分量，vy 0为所述待处理图像块内左上角像素点位置对应的运动矢量的竖直分量，vx 1为所述待处理图像块内右上角像素点位置对应的运动矢量的水平分量，vy 1为所述待处理图像块内右上角像素点位置对应的运动矢量的竖直分量，vx 2为所述待处理图像块内左下角像素点位置对应的运动矢量的水平分量，vy 2为所述待处理图像块内左下角像素点位置对应的运动矢量的竖直分量，vx 4为所述第一预设位置对应的运动矢量的水平分量，vy 4为所述第一预设位置对应的运动矢量的竖直分量，vx 5为所述第二预设位置对应的运动矢量的水平分量，vy 5为所述第二预设位置对应的运动矢量的竖直分量，vx 6为所述第三预设位置对应的运动矢量的水平分量，vy 6为所述第三预设位置对应的运动矢量的竖直分量，x 0为所述待处理图像块内左上角像素点位置横坐标，y 0为所述待处理图像块内左上角像素点位置纵坐标，x 1为所述待处理图像块内右上角像素点位置横坐标，y 1为所述待处理图像块内右上角像素点位置纵坐标，x 2为所述待处理图像块内左下角像素点位置横坐标，y 2为所述待处理图像块内左下角像素点位置纵坐标。
基于第一方面，在可能的实施方式中，对于当前块的每一个子块(一个子块也可以等效为一个运动补偿单元，子块的宽和高小于当前块的宽和高)，可采用运动补偿单元中预设位置像素点的运动信息来表示该运动补偿单元内所有像素点的运动信息。假设运动补偿单元的尺寸为MxN，则预设位置像素点可以为运动补偿单元中心点(M/2,N/2)、左上像素点(0,0)，右上像素点(M-1,0)，或其他位置的像素点。那么，根据当前块的控制点运动信息以及当前采用的仿射运动模型，可获得当前块中每个子块的运动矢量值，后续可根据所述子块的运动矢量值进行运动补偿得到该子块的像素预测值。
基于第一方面，在可能的实施方式中，如果当前块的仿射运动模型为4参数仿射运动 模型，则所述预设像素点位置包括所述待处理图像块内左上角像素点位置和所述待处理图像块内右上角像素点位置，所述根据所述预设像素点位置对应的运动矢量，插值计算出所述待处理图像块中多个子块位置对应的运动矢量，包括根据如下公式计算出所述待处理图像块中多个子块位置对应的运动矢量：
Figure PCTCN2019091364-appb-000007
其中，W为所述待处理图像块的宽度，vx为所述多个子块位置中位于(x,y)的一个对应的运动矢量的水平分量，vy为所述多个子块位置中位于(x,y)的一个对应的运动矢量的竖直分量。
基于第一方面，在可能的实施方式中，如果当前块的仿射运动模型为6参数仿射运动模型，则所述根据所述预设像素点位置对应的运动矢量，插值计算出所述待处理图像块中多个子块位置对应的运动矢量，包括根据如下公式计算出所述待处理图像块中多个子块位置对应的运动矢量：
Figure PCTCN2019091364-appb-000008
其中，W为所述待处理图像块的宽度，H为所述待处理图像块的高度，vx为所述多个子块位置中位于(x,y)的一个对应的运动矢量的水平分量，vy为所述多个子块位置中位于(x,y)的一个对应的运动矢量的竖直分量。
第二方面，本发明实施例提供了一种设备，该设备包括：参考块获取模块，用于获取所述视频数据中的待处理图像块的一个空域参考块；子块确定模块，用于确定所述空域参考块中多个预设子块位置；第一计算模块，用于根据所述预设子块位置对应的运动矢量，插值计算出所述待处理图像块预设像素点位置对应的运动矢量；第二计算模块，用于根据所述预设像素点位置对应的运动矢量，插值计算出所述待处理图像块中多个子块位置对应的运动矢量。
具体实施例中，所述设备的各个模块可用于实现第一方面所描述的方法。
第三方面，本发明实施例提供了一种用于解码视频的设备，该设备包括：
存储器，用于存储码流形式的视频数据；
解码器，用于获取所述视频数据中的待处理图像块的一个空域参考块；确定所述空域参考块中多个预设子块位置；根据所述预设子块位置对应的运动矢量，插值计算出所述待处理图像块预设像素点位置对应的运动矢量；根据所述预设像素点位置对应的运动矢量，插值计算出所述待处理图像块中多个子块位置对应的运动矢量，其中，所述多个子块位置对应的运动矢量分别用于所述多个子块的运动矢量的预测。
基于第三方面，在可能的实施例中，解码器具体用于：按照预设顺序确定所述待处理图像块的一个或多个预设空域位置的候选参考块的可用性；获得在所述预设顺序中第一个可用的候选参考块作为所述空域参考块。
基于第三方面，在可能的实施例中，当所述候选参考块与所述待处理图像块位于同一 图像区域内，并且所述候选参考块基于所述仿射运动模型获得运动矢量时，确定所述候选参考块可用。
基于第三方面，在可能的实施例中，所述预设空域位置的候选参考块包括：位于所述待处理图像块正上方、正左方、右上方、左下方和左上方的相邻图像块；
所述解码器具体用于：按照正左方相邻图像块、正上方相邻图像块、右上方相邻图像块、左下方相邻图像块、左上方相邻图像块的顺序依次检查所述候选参考块的可用性，直到确定所述第一个可用的候选参考块。
其中，所述子块位置包括：所述子块内左上角像素点的位置；或者，所述子块的几何中心的位置，或者，所述子块内距离几何中心位置最近的一个像素点的位置。
基于第三方面，在可能的实施例中，所述多个预设子块位置中的两个预设子块位置之间的距离为S，S为2的K次幂，K为非负整数。
基于第三方面，在可能的实施例中，所述仿射运动模型为4参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)和第二预设位置(x4+M/2+P,y4+N/2)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，P为2的K次幂，K为非负整数，K小于U，U为所述空域参考块的宽度。
基于第三方面，在可能的实施例中，所述仿射运动模型为4参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)和第三预设位置(x4+M/2,y4+N/2+Q)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，Q为2的R次幂，R为非负整数，Q小于V，V为所述空域参考块的高度。
基于第三方面，在可能的实施例中，所述仿射运动模型为4参数仿射运动模型，所述预设像素点位置包括所述待处理图像块内左上角像素点位置，解码器具体用于，根据如下公式计算出所述待处理图像块预设像素点位置对应的运动矢量：
Figure PCTCN2019091364-appb-000009
Figure PCTCN2019091364-appb-000010
Figure PCTCN2019091364-appb-000011
其中，vx 0为所述待处理图像块内左上角像素点位置对应的运动矢量的水平分量，vy 0为所述待处理图像块内左上角像素点位置对应的运动矢量的竖直分量，vx 1为所述待处理图像块内右上角像素点位置对应的运动矢量的水平分量，vy 1为所述待处理图像块内右上角像素点位置对应的运动矢量的竖直分量，vx 2为所述待处理图像块内左下角像素点位置对应的运动 矢量的水平分量，vy 2为所述待处理图像块内左下角像素点位置对应的运动矢量的竖直分量，vx 4为所述第一预设位置对应的运动矢量的水平分量，vy 4为所述第一预设位置对应的运动矢量的竖直分量，vx 5为所述第二预设位置对应的运动矢量的水平分量，vy 5为所述第二预设位置对应的运动矢量的竖直分量，x 0为所述待处理图像块内左上角像素点位置横坐标，y 0为所述待处理图像块内左上角像素点位置纵坐标，x 1为所述待处理图像块内右上角像素点位置横坐标，y 1为所述待处理图像块内右上角像素点位置纵坐标，x 2为所述待处理图像块内左下角像素点位置横坐标，y 2为所述待处理图像块内左下角像素点位置纵坐标。
基于第三方面，在可能的实施例中，所述仿射运动模型为4参数仿射运动模型，所述预设像素点位置包括所述待处理图像块内左上角像素点位置和所述待处理图像块内右上角像素点位置，解码器具体用于，根据如下公式计算出所述待处理图像块中多个子块位置对应的运动矢量：
Figure PCTCN2019091364-appb-000012
其中，W为所述待处理图像块的宽度，vx为所述多个子块位置中位于(x,y)的一个对应的运动矢量的水平分量，vy为所述多个子块位置中位于(x,y)的一个对应的运动矢量的竖直分量。
基于第三方面，在可能的实施例中，所述仿射运动模型为6参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)，第二预设位置(x4+M/2+P,y4+N/2)和第三预设位置(x4+M/2,y4+N/2+Q)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，P为2的K次幂，Q为2的R次幂，K和R为非负整数，P小于U，Q小于V,U为所述空域参考块的宽度,V为所述空域参考块的高度。
基于第三方面，在可能的实施例中，所述仿射运动模型为6参数仿射运动模型，所述预设像素点位置包括所述待处理图像块内左上角像素点位置，所述待处理图像块内右上角像素点位置和所述待处理图像块内左下角像素点位置，解码器具体用于，根据如下公式计算出所述待处理图像块预设像素点位置对应的运动矢量：
Figure PCTCN2019091364-appb-000013
Figure PCTCN2019091364-appb-000014
Figure PCTCN2019091364-appb-000015
其中，vx 0为所述待处理图像块内左上角像素点位置对应的运动矢量的水平分量，vy 0为所 述待处理图像块内左上角像素点位置对应的运动矢量的竖直分量，vx 1为所述待处理图像块内右上角像素点位置对应的运动矢量的水平分量，vy 1为所述待处理图像块内右上角像素点位置对应的运动矢量的竖直分量，vx 2为所述待处理图像块内左下角像素点位置对应的运动矢量的水平分量，vy 2为所述待处理图像块内左下角像素点位置对应的运动矢量的竖直分量，vx 4为所述第一预设位置对应的运动矢量的水平分量，vy 4为所述第一预设位置对应的运动矢量的竖直分量，vx 5为所述第二预设位置对应的运动矢量的水平分量，vy 5为所述第二预设位置对应的运动矢量的竖直分量，vx 6为所述第三预设位置对应的运动矢量的水平分量，vy 6为所述第三预设位置对应的运动矢量的竖直分量，x 0为所述待处理图像块内左上角像素点位置横坐标，y 0为所述待处理图像块内左上角像素点位置纵坐标，x 1为所述待处理图像块内右上角像素点位置横坐标，y 1为所述待处理图像块内右上角像素点位置纵坐标，x 2为所述待处理图像块内左下角像素点位置横坐标，y 2为所述待处理图像块内左下角像素点位置纵坐标。
基于第三方面，在可能的实施例中，所述仿射运动模型为6参数仿射运动模型，解码器具体用于，根据如下公式计算出所述待处理图像块中多个子块位置对应的运动矢量：
Figure PCTCN2019091364-appb-000016
其中，W为所述待处理图像块的宽度，H为所述待处理图像块的高度，vx为所述多个子块位置中位于(x,y)的一个对应的运动矢量的水平分量，vy为所述多个子块位置中位于(x,y)的一个对应的运动矢量的竖直分量。
基于第三方面，在可能的实施例中，当所述待处理图像块的上边缘所在的直线和所述待处理图像块所在的编码树单元CTU的上边缘所在的直线重合，且所述空域参考块位于所述待处理图像块的正上方、左上方或右上方时，所述多个预设子块位置对应的子块中的至少两个子块与所述待处理图像块的上边缘邻接。
基于第三方面，在可能的实施例中，当所述待处理图像块的左边缘所在的直线和所述待处理图像块所在的编码树单元CTU的左边缘所在的直线重合，且所述空域参考块位于所述待处理图像块的正左方、左上方或左下方时，所述多个预设子块位置对应的子块中的至少两个子块与所述待处理图像块的左边缘邻接。
本发明第一方面描述的方法可由根据本发明第三方面的设备执行。本发明第一方面的方法的其它特征和实现方式直接取决于根据本发明第三方面的设备的功能性及其不同实现方式。
第四方面，本发明实施例提供了一种用于编码视频的设备，该设备包括：
存储器，用于存储码流形式的视频数据；
编码器，用于获取所述视频数据中的待处理图像块的一个空域参考块；确定所述空域参考块中多个预设子块位置；根据所述预设子块位置对应的运动矢量，插值计算出所述待处理图像块预设像素点位置对应的运动矢量；根据所述预设像素点位置对应的运动矢量，插值计算出所述待处理图像块中多个子块位置对应的运动矢量，其中，所述多个子块位置对应的运动矢量分别用于所述多个子块的运动矢量的预测。
其中，所述编码器的具体功能实现可参考第三方面描述的解码器的功能描述，这里不再赘述。
本发明第一方面的方法可由根据本发明第四方面描述的设备执行。本发明第一方面的方法的其它特征和实现方式直接取决于根据本发明第四方面的设备的功能性及其不同实现方式。
第五方面，本发明涉及解码视频流的装置，包含处理器和存储器。所述存储器存储指令，所述指令使得所述处理器执行根据第一方面的方法。
第六方面，本发明实施例提供了解码视频流的装置，包含处理器和存储器。所述存储器存储指令，所述指令使得所述处理器执行根据第一方面的方法。
第七方面，本发明实施例提供了编码视频流的装置，包含处理器和存储器。所述存储器存储指令，所述指令使得所述处理器执行根据第一方面的方法。
第八方面，本发明实施例提供了计算机可读存储介质，其上储存有指令，所述指令执行时，使得一个或多个处理器编码视频数据。所述指令使得所述一个或多个处理器执行根据第一方面任何可能实施例的方法。
第九方面，本发明实施例提供了包括程序代码的计算机程序，所述程序代码在计算机上运行时执行根据第一方面任何可能实施例的方法。
可以看到，本发明实施例采用了改进继承的控制点运动矢量预测方法，该改进的继承的控制点运动矢量预测方法不需要利用到相邻块控制点的运动矢量，而是采用相邻块至少两个子块的运动矢量，推导当前块的控制点的运动矢量，进而根据控制点的运动矢量推导得到当前块的各个子块的运动矢量，通过运动补偿实现对当前块的预测。当前块的控制点的运动矢量后续将不需要进行存储，即当前块的控制点的运动矢量只用于该当前解码块的子块的运动矢量的推导，不用于相邻块的运动矢量预测。因此，本发明方案只需要保存子块的运动矢量，并且均采用子块的运动矢量进行运动补偿，解决运动矢量存储的问题的同时，避免了控制点所在的子块使用了与其他子块不一致的运动矢量进行运动补偿，提高了预测的准确性。
附图说明
为了更清楚地说明本发明实施例或背景技术中的技术方案，下面将对本发明实施例或背景技术中所需要使用的附图进行说明。
图1A是用于实现本发明实施例的视频编码及解码系统10实例的框图；
图1B是用于实现本发明实施例的视频译码系统40实例的框图；
图2是用于实现本发明实施例的编码器20实例结构的框图；
图3是用于实现本发明实施例的解码器30实例结构的框图；
图4是用于实现本发明实施例的视频译码设备400实例的框图；
图5是用于实现本发明实施例的另一种编码装置或解码装置实例的框图；
图6是一种对当前块的实例操作的场景示意图；
图7是又一种对当前块的实例操作的场景示意图；
图8是又一种对当前块的实例操作的场景示意图；
图9是又一种对当前块的实例操作的场景示意图；
图10是又一种对当前块的实例操作的场景示意图；
图11是本发明实施例提供的一种基于仿射运动模型的运动矢量预测方法流程图；
图12是本发明实施例提供的又一种基于仿射运动模型的运动矢量预测方法流程图；
图13是又一种对当前块的实例操作的场景示意图；
图14是本发明实施例提供的又一种基于仿射运动模型的运动矢量预测方法流程图；
图15是用于实现本发明实施例的一种设备的结构框图。
具体实施方式
下面结合本发明实施例中的附图对本发明实施例进行描述。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发明实施例的具体方面或可使用本发明实施例的具体方面的附图。应理解，本发明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，且本发明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。
本发明实施例所涉及的技术方案不仅可能应用于现有的视频编码标准中(如H.264、HEVC等标准)，还可能应用于未来的视频编码标准中(如H.266标准)。本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。下面先对本发明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CU可以按照四叉树进行划分为更小的CU，而更小的CU还可以继续划分，从而形成一种四叉树结构，CU是对编码图像进行划分和编码的基本单元。对于PU和TU也有类似的树结构，PU可以对应预测块，是预测编码的基本单元。对CU按照划分模式进一步划分成多个PU。TU可以对应变换块，是对预测残差进行变换的基本单元。然而，无论CU，PU还是TU，本质上都属于块(或称图像块)的概念。
例如在HEVC中，通过使用表示为编码树的四叉树结构将CTU拆分为多个CU。在CU层级处作出是否使用图片间(时间)或图片内(空间)预测对图片区域进行编码的决策。每个CU可以根据PU拆分类型进一步拆分为一个、两个或四个PU。一个PU内应用相同的预测过程，并在PU基础上将相关信息传输到解码器。在通过基于PU拆分类型应用预测过程获取残差块之后，可以根据类似于用于CU的编码树的其它四叉树结构将CU分割成变换单元(transform unit，TU)。在视频压缩技术最新的发展中，使用四叉树和二叉树(Quad-tree and binary tree，QTBT)分割帧来分割编码块。在QTBT块结构中，CU可以为正方形或矩形形状。
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。
下面描述本发明实施例所应用的系统架构。参见图1A，图1A示例性地给出了本发明 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。本发明实施例中，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，以实现本发明所描述的色度块预测方法在编码侧的应用。
通信接口22，可用于接收经编码图片数据21，并可通过链路13将经编码图片数据21传输至目的地设备14或任何其它设备(如存储器)，以用于存储或直接重构，所述其它设备可为任何用于解码或存储的设备。通信接口22可例如用于将经编码图片数据21封装成合适的格式，例如数据包，以在链路13上传输。
目的地设备14包括解码器30，另外可选地，目的地设备14还可以包括通信接口28、图片后处理器32和显示设备34。分别描述如下：
通信接口28，可用于从源设备12或任何其它源接收经编码图片数据21，所述任何其它源例如为存储设备，存储设备例如为经编码图片数据存储设备。通信接口28可以用于藉由源设备12和目的地设备14之间的链路13或藉由任何类别的网络传输或接收经编码图片数据21，链路13例如为直接有线或无线连接，任何类别的网络例如为有线或无线网络或其任何组合，或任何类别的私网和公网，或其任何组合。通信接口28可以例如用于解封装通信接口22所传输的数据包以获取经编码图片数据21。
通信接口28和通信接口22都可以配置为单向通信接口或者双向通信接口，以及可以用于例如发送和接收消息来建立连接、确认和交换任何其它与通信链路和/或例如经编码图 片数据传输的数据传输有关的信息。
解码器30(或称为解码器30)，用于接收经编码图片数据21并提供经解码图片数据31或经解码图片31(下文将进一步基于图3或图4或图5描述解码器30的结构细节)。在一些实施例中，解码器30可以用于执行后文所描述的各个实施例，以实现本发明所描述的色度块预测方法在解码侧的应用。
图片后处理器32，用于对经解码图片数据31(也称为经重构图片数据)执行后处理，以获得经后处理图片数据33。图片后处理器32执行的后处理可以包括：色彩格式转换(例如，从YUV格式转换为RGB格式)、调色、整修或重采样，或任何其它处理，还可用于将将经后处理图片数据33传输至显示设备34。
显示设备34，用于接收经后处理图片数据33以向例如用户或观看者显示图片。显示设备34可以为或可以包括任何类别的用于呈现经重构图片的显示器，例如，集成的或外部的显示器或监视器。例如，显示器可以包括液晶显示器(liquid crystal display，LCD)、有机发光二极管(organic light emitting diode，OLED)显示器、等离子显示器、投影仪、微LED显示器、硅基液晶(liquid crystal on silicon，LCoS)、数字光处理器(digital light processor，DLP)或任何类别的其它显示器。
虽然，图1A将源设备12和目的地设备14绘示为单独的设备，但设备实施例也可以同时包括源设备12和目的地设备14或同时包括两者的功能性，即源设备12或对应的功能性以及目的地设备14或对应的功能性。在此类实施例中，可以使用相同硬件和/或软件，或使用单独的硬件和/或软件，或其任何组合来实施源设备12或对应的功能性以及目的地设备14或对应的功能性。
本领域技术人员基于描述明显可知，不同单元的功能性或图1A所示的源设备12和/或目的地设备14的功能性的存在和(准确)划分可能根据实际设备和应用有所不同。源设备12和目的地设备14可以包括各种设备中的任一个，包含任何类别的手持或静止设备，例如，笔记本或膝上型计算机、移动电话、智能手机、平板或平板计算机、摄像机、台式计算机、机顶盒、电视机、相机、车载设备、显示设备、数字媒体播放器、视频游戏控制台、视频流式传输设备(例如内容服务服务器或内容分发服务器)、广播接收器设备、广播发射器设备等，并可以不使用或使用任何类别的操作系统。
编码器20和解码器30都可以实施为各种合适电路中的任一个，例如，一个或多个微处理器、数字信号处理器(digital signal processor，DSP)、专用集成电路(application-specific integrated circuit，ASIC)、现场可编程门阵列(field-programmable gate array，FPGA)、离散逻辑、硬件或其任何组合。如果部分地以软件实施所述技术，则设备可将软件的指令存储于合适的非暂时性计算机可读存储介质中，且可使用一或多个处理器以硬件执行指令从而执行本公开的技术。前述内容(包含硬件、软件、硬件与软件的组合等)中的任一者可视为一或多个处理器。
在一些情况下，图1A中所示视频编码及解码系统10仅为示例，本申请的技术可以适用于不必包含编码和解码设备之间的任何数据通信的视频编码设置(例如，视频编码或视频解码)。在其它实例中，数据可从本地存储器检索、在网络上流式传输等。视频编码设备可以对数据进行编码并且将数据存储到存储器，和/或视频解码设备可以从存储器检索数据 并且对数据进行解码。在一些实例中，由并不彼此通信而是仅编码数据到存储器和/或从存储器检索数据且解码数据的设备执行编码和解码。
参见图1B，图1B是根据一示例性实施例的包含图2的编码器20和/或图3的解码器30的视频译码系统40的实例的说明图。视频译码系统40可以实现本发明实施例的各种技术的组合。在所说明的实施方式中，视频译码系统40可以包含成像设备41、编码器20、解码器30(和/或藉由处理单元46的逻辑电路47实施的视频编/解码器)、天线42、一个或多个处理器43、一个或多个存储器44和/或显示设备45。
如图1B所示，成像设备41、天线42、处理单元46、逻辑电路47、编码器20、解码器30、处理器43、存储器44和/或显示设备45能够互相通信。如所论述，虽然用编码器20和解码器30绘示视频译码系统40，但在不同实例中，视频译码系统40可以只包含编码器20或只包含解码器30。
在一些实例中，天线42可以用于传输或接收视频数据的经编码比特流。另外，在一些实例中，显示设备45可以用于呈现视频数据。在一些实例中，逻辑电路47可以通过处理单元46实施。处理单元46可以包含专用集成电路(application-specific integrated circuit，ASIC)逻辑、图形处理器、通用处理器等。视频译码系统40也可以包含可选的处理器43，该可选处理器43类似地可以包含专用集成电路(application-specific integrated circuit，ASIC)逻辑、图形处理器、通用处理器等。在一些实例中，逻辑电路47可以通过硬件实施，如视频编码专用硬件等，处理器43可以通过通用软件、操作系统等实施。另外，存储器44可以是任何类型的存储器，例如易失性存储器(例如，静态随机存取存储器(Static Random Access Memory，SRAM)、动态随机存储器(Dynamic Random Access Memory，DRAM)等)或非易失性存储器(例如，闪存等)等。在非限制性实例中，存储器44可以由超速缓存内存实施。在一些实例中，逻辑电路47可以访问存储器44(例如用于实施图像缓冲器)。在其它实例中，逻辑电路47和/或处理单元46可以包含存储器(例如，缓存等)用于实施图像缓冲器等。
在一些实例中，通过逻辑电路实施的编码器20可以包含(例如，通过处理单元46或存储器44实施的)图像缓冲器和(例如，通过处理单元46实施的)图形处理单元。图形处理单元可以通信耦合至图像缓冲器。图形处理单元可以包含通过逻辑电路47实施的编码器20，以实施参照图2和/或本文中所描述的任何其它编码器系统或子系统所论述的各种模块。逻辑电路可以用于执行本文所论述的各种操作。
在一些实例中，解码器30可以以类似方式通过逻辑电路47实施，以实施参照图3的解码器30和/或本文中所描述的任何其它解码器系统或子系统所论述的各种模块。在一些实例中，逻辑电路实施的解码器30可以包含(通过处理单元2820或存储器44实施的)图像缓冲器和(例如，通过处理单元46实施的)图形处理单元。图形处理单元可以通信耦合至图像缓冲器。图形处理单元可以包含通过逻辑电路47实施的解码器30，以实施参照图3和/或本文中所描述的任何其它解码器系统或子系统所论述的各种模块。
在一些实例中，天线42可以用于接收视频数据的经编码比特流。如所论述，经编码比特流可以包含本文所论述的与编码视频帧相关的数据、指示符、索引值、模式选择数据等， 例如与编码分割相关的数据(例如，变换系数或经量化变换系数，(如所论述的)可选指示符，和/或定义编码分割的数据)。视频译码系统40还可包含耦合至天线42并用于解码经编码比特流的解码器30。显示设备45用于呈现视频帧。
应理解，本发明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，本发明实施例描述的基于仿射运动模型的运动矢量预测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，本发明实施例中的编码器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示出用于实现本发明实施例的编码器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发明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，本发明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，在本发明实施例中，编码器20可用于实现后文实施例中描述的基于仿射运动模型的运动矢量预测方法。
参见图3，图3示出用于实现本发明实施例的解码器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。在本发明的一实例中，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，在本发明实施例中，解码器30用于实现后文实施例中描述的基于仿射运动模型的运动矢量预测方法。
参见图4，图4是本发明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，以实现本发明实施例所提供的色度块预测方法。例如，编码/解码模块470实现、处理或提供各种编码操作。因此，通过编码/解码模块470为视频译码设备400的功能提供了实质性的改进，并影响了视频译码设备400到不同状态的转换。或者，以存储在存储器460中并由处理器430执行的指令来实现编码/解码模块470。
存储器460包括一个或多个磁盘、磁带机和固态硬盘，可以用作溢出数据存储设备，用于在选择性地执行这些程序时存储程序，并存储在程序执行过程中读取的指令和数据。存储器460可以是易失性和/或非易失性的，可以是只读存储器(ROM)、随机存取存储器(RAM)、随机存取存储器(ternary content-addressable memory，TCAM)和/或静态随机存取存储器(SRAM)。
参见图5，图5是根据一示例性实施例的可用作图1A中的源设备12和目的地设备14中的任一个或两个的装置500的简化框图。装置500可以实现本申请的技术，用于实现色度块预测的装置500可以采用包含多个计算设备的计算系统的形式，或采用例如移动电话、平板计算机、膝上型计算机、笔记本电脑、台式计算机等单个计算设备的形式。
装置500中的处理器502可以为中央处理器。或者，处理器502可以为现有的或今后将研发出的能够操控或处理信息的任何其它类型的设备或多个设备。如图所示，虽然可以使用例如处理器502的单个处理器实践所揭示的实施方式，但是使用一个以上处理器可以实现速度和效率方面的优势。
在一实施方式中，装置500中的存储器504可以为只读存储器(Read Only Memory，ROM)设备或随机存取存储器(random access memory，RAM)设备。任何其他合适类型的存储设备都可以用作存储器504。存储器504可以包括代码和由处理器502使用总线512访问的数据506。存储器504可进一步包括操作系统508和应用程序510，应用程序510包含至少一个准许处理器502执行本文所描述的方法的程序。例如，应用程序510可以包括应用1到N，应用1到N进一步包括执行本文所描述的方法的视频编码应用。装置500还可包含采用从存储器514形式的附加存储器，该从存储器514例如可以为与移动计算设备 一起使用的存储卡。因为视频通信会话可能含有大量信息，这些信息可以整体或部分存储在从存储器514中，并按需要加载到存储器504用于处理。
装置500还可包含一或多个输出设备，例如显示器518。在一个实例中，显示器518可以为将显示器和可操作以感测触摸输入的触敏元件组合的触敏显示器。显示器518可以通过总线512耦合于处理器502。除了显示器518还可以提供其它准许用户对装置500编程或以其它方式使用装置500的输出设备，或提供其它输出设备作为显示器518的替代方案。当输出设备是显示器或包含显示器时，显示器可以以不同方式实现，包含通过液晶显示器(liquid crystal display，LCD)、阴极射线管(cathode-ray tube，CRT)显示器、等离子显示器或发光二极管(light emitting diode，LED)显示器，如有机LED(organic LED，OLED)显示器。
装置500还可包含图像感测设备520或与其连通，图像感测设备520例如为相机或为现有的或今后将研发出的可以感测图像的任何其它图像感测设备520，所述图像例如为运行装置500的用户的图像。图像感测设备520可以放置为直接面向运行装置500的用户。在一实例中，可以配置图像感测设备520的位置和光轴以使其视野包含紧邻显示器518的区域且从该区域可见显示器518。
装置500还可包含声音感测设备522或与其连通，声音感测设备522例如为麦克风或为现有的或今后将研发出的可以感测装置500附近的声音的任何其它声音感测设备。声音感测设备522可以放置为直接面向运行装置500的用户，并可以用于接收用户在运行装置500时发出的声音，例如语音或其它发声。
虽然图5中将装置500的处理器502和存储器504绘示为集成在单个单元中，但是还可以使用其它配置。处理器502的运行可以分布在多个可直接耦合的机器中(每个机器具有一个或多个处理器)，或分布在本地区域或其它网络中。存储器504可以分布在多个机器中，例如基于网络的存储器或多个运行装置500的机器中的存储器。虽然此处只绘示单个总线，但装置500的总线512可以由多个总线形成。进一步地，从存储器514可以直接耦合至装置500的其它组件或可以通过网络访问，并且可包括单个集成单元，例如一个存储卡，或多个单元，例如多个存储卡。因此，可以以多种配置实施装置500。
为了更好理解本发明实施例的技术方案，下面进一步描述本发明实施例涉及的帧间预测模式、非平动运动模型、继承的控制点运动矢量预测方法以及构造的控制点运动矢量预测方法。
1)帧间预测模式。在HEVC中，使用两种帧间预测模式，分别为先进的运动矢量预测(advanced motion vector prediction，AMVP)模式和融合(merge)模式。
对于AMVP模式，先遍历当前块空域或者时域相邻的已编码块(记为相邻块)，根据各个相邻块的运动信息构建候选运动矢量列表(也可以称为运动信息候选列表)，然后通过率失真代价从候选运动矢量列表中确定最优的运动矢量，将率失真代价最小的候选运动信息作为当前块的运动矢量预测值(motion vector predictor，MVP)。其中，相邻块的位置及其遍历顺序都是预先定义好的。率失真代价由公式(1)计算获得，其中，J表示率失真代价RD Cost，SAD为使用候选运动矢量预测值进行运动估计后得到的预测像素值与原始像素值之 间的绝对误差和(sum of absolute differences，SAD)，R表示码率，λ表示拉格朗日乘子。编码端将选择的运动矢量预测值在候选运动矢量列表中的索引值和参考帧索引值传递到解码端。进一步地，在MVP为中心的邻域内进行运动搜索获得当前块实际的运动矢量，编码端将MVP与实际运动矢量之间的差值(motion vector difference)传递到解码端。
J＝SAD+λR(1)
对于Merge模式，先通过当前块空域或者时域相邻的已编码块的运动信息，构建候选运动矢量列表，然后通过计算率失真代价从候选运动矢量列表中确定最优的运动信息作为当前块的运动信息，再将最优的运动信息在候选运动矢量列表中位置的索引值(记为merge index，下同)传递到解码端。当前块空域和时域候选运动信息如图6所示，空域候选运动信息来自于空间相邻的5个块(A0,A1,B0,B1和B2)，若相相邻块不可得(相相邻块不存在或者相相邻块未编码或者相相邻块采用的预测模式不为帧间预测模式)，则该相相邻块的运动信息不加入候选运动矢量列表。当前块的时域候选运动信息根据参考帧和当前帧的图序计数(picture order count，POC)对参考帧中对应位置块的MV进行缩放后获得。首先判断参考帧中T位置的块是否可得，若不可得则选择C位置的块。
与AMVP模式类似，Merge模式的相邻块的位置及其遍历顺序也是预先定义好的，且相邻块的位置及其遍历顺序在不同模式下可能不同。
可以看到，在AMVP模式和Merge模式中，都需要维护一个候选运动矢量列表。每次向候选列表中加入新的运动信息之前都会先检查列表中是否已经存在相同的运动信息，如果存在则不会将该运动信息加入列表中。我们将这个检查过程称为候选运动矢量列表的修剪。列表修剪是为了防止列表中出现相同的运动信息，避免冗余的率失真代价计算。
在HEVC的帧间预测中，编码块内的所有像素都采用了相同的运动信息(即编码块中所有像素点的运动一致)，然后根据运动信息进行运动补偿，得到编码块的像素的预测值。然而在编码块内，并不是所有的像素都有相同的运动特性，采用相同的运动信息可能会导致运动补偿预测的不准确，进而增加了残差信息。
也就是说，现有的视频编码标准使用基于平动运动模型的块匹配运动估计，但是由于在现实世界中，运动多种多样，存在很多非平动运动的物体，如旋转的的物体，在不同方向旋转的过山车，投放的烟花和电影中的一些特技动作，特别是在UGC场景中的运动物体，对它们的编码，如果采用当前编码标准中的基于平动运动模型的块运动补偿技术，编码效率会受到很大的影响，因此，产生了非平动运动模型，比如仿射运动模型，以便进一步提高编码效率。
基于此，根据运动模型的不同，AMVP模式可以分为基于平动模型的AMVP模式以及基于非平动模型的AMVP模式；Merge模式可以分为基于平动模型的Merge模式和基于非平动运动模型的Merge模式。
2)非平动运动模型。非平动运动模型预测指在编解码端使用相同的运动模型推导出当前块内每一个子运动补偿单元的运动信息，根据子运动补偿单元的运动信息进行运动补偿，得到预测块，从而提高预测效率。其中，本发明实施例中涉及到的子运动补偿单元可以是一个像素点或按照特定方法划分的大小为N 1×N 2的像素块，其中，N 1和N 2均为正整数，N 1可以等于N 2，也可以不等于N 2。
常用的非平动运动模型有4参数仿射运动模型或者6参数仿射运动模型，在可能的应用场景中，还有8参数双线性模型。下面将分别进行说明。
对于4参数仿射运动模型，4参数仿射运动模型如下公式(2)所示：
Figure PCTCN2019091364-appb-000017
4参数仿射运动模型可以通过两个像素点的运动矢量及其相对于当前块左上顶点像素的坐标来表示，将用于表示运动模型参数的像素点称为控制点。若采用左上顶点(0,0)和右上顶点(W,0)像素点作为控制点，则先确定当前块左上顶点和右上顶点控制点的运动矢量(vx0,vy0)和(vx1,vy1)，然后根据如下公式(3)得到当前块中每一个子运动补偿单元的运动信息，其中(x,y)为子运动补偿单元相对于当前块左上顶点像素的坐标，W为当前块的宽。
Figure PCTCN2019091364-appb-000018
对于6参数仿射运动模型，6参数仿射运动模型如下公式(4)所示：
Figure PCTCN2019091364-appb-000019
6参数仿射运动模型可以通过三个像素点的运动矢量及其相对于当前块左上顶点像素的坐标来表示。若采用左上顶点(0,0)、右上顶点(W,0)和左下顶点(0,H)像素点作为控制点，则先确定当前块左上顶点、右上顶点和左下顶点控制点的运动矢量分别为(vx0,vy0)和(vx1,vy1)和(vx2,vy2)，然后根据如下公式(5)得到当前块中每一个子运动补偿单元的运动信息，其中(x,y)为子运动补偿单元相对于当前块的左上顶点像素的坐标，W和H分别为当前块的宽和高。
Figure PCTCN2019091364-appb-000020
对于8参数双线性模型，8参数双线性模型如下公式(6)所示：
Figure PCTCN2019091364-appb-000021
8参数双线性模型可以通过四个像素点的运动矢量及其相对于当前编码块左上顶点像素的坐标来表示。若采用左上顶点(0,0)、右上顶点(W,0)、左下顶点(0,H)和右下定点(W,H)像素点作为控制点，则先确定当前编码块左上顶点、右上顶点、左下顶点和右下顶点控制点的运动矢量(vx0,vy0)、(vx1,vy1)、(vx2,vy2)和(vx3,vy3)，然后根据如下公式(7)推导得到当前编码块中每一个子运动补偿单元的运动信息，其中(x,y)为子运动补偿单元相对于当前编码块左上顶点像素的坐标，W和H分别为当前编码块的宽和高。
Figure PCTCN2019091364-appb-000022
采用仿射运动模型进行预测的编码块又可称为仿射编码块，通过上文可以看出，仿射运动模型与仿射编码块的控制点的运动信息直接相关。
通常的，可以使用基于仿射运动模型的AMVP模式或者基于仿射运动模型的Merge模式， 获得仿射编码块的控制点的运动信息。进一步的，对于基于仿射运动模型的AMVP模式或者基于仿射运动模型的Merge模式，当前编码块的控制点的运动信息可以通过继承的控制点运动矢量预测方法或者构造的控制点运动矢量预测方法得到。下面进一步描述这两种方法。
3)继承的控制点运动矢量预测方法。继承的控制点运动矢量预测方法是指利用当前块的相邻已编码的仿射编码块的运动模型，确定当前块的候选的控制点运动矢量。
以图7所示的当前块为例，按照设定的顺序，比如A1→B1→B0→A0→B2的顺序遍历当前块周围的相邻位置块，找到该当前块的相邻位置块所在的仿射编码块，获得该仿射编码块的控制点运动信息，进而通过仿射编码块的控制点运动信息构造的运动模型，推导出当前块的控制点运动矢量(用于Merge模式)或者控制点的运动矢量预测值(用于AMVP模式)。A1→B1→B0→A0→B2仅作为一种示例，其它组合的顺序也适用于本发明实施例。另外，相邻位置块不仅限于A1、B1、B0、A0、B2。其中，相邻位置块可以为一个像素点，或者，按照特定方法划分的预设大小的像素块，比如可以为一个4x4的像素块，也可以为一个4x2的像素块，也可以为其他大小的像素块，不作限定。其中，仿射编码块为在编码阶段采用仿射运动模型进行预测的与当前块相邻的已编码块(也可简称为相邻仿射编码块)。
下面以如图7所示出的A1为例描述当前块的候选的控制点运动矢量的确定过程，其他情况以此类推：
若A1所在的编码块为4参数仿射编码块(即该仿射编码块采用4参数仿射运动模型进行预测)，则获得该仿射编码块左上顶点(x4,y4)的运动矢量(vx4,vy4)、右上顶点(x5,y5)的运动矢量(vx5,vy5)。
然后，利用如下公式(8)计算获得当前仿射编码块左上顶点(x0,y0)的运动矢量(vx0,vy0)：
Figure PCTCN2019091364-appb-000023
利用如下公式(9)计算获得当前仿射编码块右上顶点(x1,y1)的运动矢量(vx1,vy1)：
Figure PCTCN2019091364-appb-000024
通过如上基于A1所在的仿射编码块获得的当前块的左上顶点(x0,y0)的运动矢量(vx0,vy0)、右上顶点(x1,y1)的运动矢量(vx1,vy1)的组合为当前块的候选的控制点运动矢量。
若A1所在的编码块为6参数仿射编码块(即该仿射编码块采用6参数仿射运动模型进行预测)，则获得该仿射编码块左上顶点(x4,y4)的运动矢量(vx4,vy4)、右上顶点(x5,y5)的运动矢量(vx5,vy5)、左下顶点(x6,y6)的运动矢量(vx6,vy6)。
然后，利用如下公式(10)计算获得当前块左上顶点(x0,y0)的运动矢量(vx0,vy0)：
Figure PCTCN2019091364-appb-000025
利用如下公式(11)计算获得当前块右上顶点(x1,y1)的运动矢量(vx1,vy1)：
Figure PCTCN2019091364-appb-000026
利用如下公式(12)计算获得当前块左下顶点(x2,y2)的运动矢量(vx2,vy2)：
Figure PCTCN2019091364-appb-000027
通过如上基于A1所在的仿射编码块获得的当前块的左上顶点(x0,y0)的运动矢量(vx0,vy0)、右上顶点(x1,y1)的运动矢量(vx1,vy1)、当前块左下顶点(x2,y2)的运动矢量(vx2,vy2)的组合为当前块的候选的控制点运动矢量。
需要说明的是，其他运动模型、候选位置、查找遍历顺序也可以适用于本发明实施例，本发明实施例对此不做赘述。
需要说明的是，采用其他控制点来表示相邻和当前编码块的运动模型的方法也可以适用于本发明实施例，此处不做赘述。
4)构造的控制点运动矢量(constructed control point motion vectors)预测方法。构造的控制点运动矢量预测方法是指将当前块的控制点周边邻近的已编码块的运动矢量进行组合，作为当前仿射编码块的控制点的运动矢量，而不需要考虑周边邻近的已编码块是否为仿射编码块。基于不同的预测模式(基于仿射运动模型的AMVP模式和基于仿射运动模型的Merge模式)，构造的控制点运动矢量预测方法又有所差异，下面分别进行描述。
首先描述基于仿射运动模型的AMVP模式的构造的控制点运动矢量预测方法。
以图8所示为例对该构造的控制点运动矢量预测方法进行描述，以利用当前编码块周边邻近的已编码块的运动信息确定当前块左上顶点和右上顶点的运动矢量。需要说明的是，图8仅作为一种示例。
若当前块为4参数仿射编码块(即当前块采用4参数仿射运动模型进行预测)，则可利用左上顶点相邻已编码块A2，B2或B3块的运动矢量，作为当前块左上顶点的运动矢量的候选运动矢量；利用右上顶点相邻已编码块B1或B0块的运动矢量，作为当前块右上顶点的运动矢量的候选运动矢量。将上述左上顶点和右上顶点的候选运动矢量进行组合，构成多个二元组，二元组包括的两个已编码块的运动矢量可以作为当前块的候选的控制点运动矢量，所述多个二元组可参见如下(13A)所示：
{v A2,v B1},{v A2,v B0},{v B2,v B1},{v B2,v B0},{v B3,v B1},{v B3,v B0}(13A)
其中，v A2表示A2的运动矢量，v B1表示B1的运动矢量，v B0表示B0的运动矢量，v B2表示B2的运动矢量，v B3表示B3的运动矢量。
若当前块为6参数仿射编码块(即当前块采用6参数仿射运动模型进行预测)，则可利用左上顶点相邻已编码块A2，B2或B3块的运动矢量，作为当前块左上顶点的运动矢量的候选运动矢量；利用右上顶点相邻已编码块B1或B0块的运动矢量，作为当前块右上顶点的运动矢量的候选运动矢量，利用坐下顶点相邻已编码块A0或A1的运动矢量作为当前块左下顶点的运动矢量的候选运动矢量。将上述左上顶点、右上顶点以及左下顶点的候选运动矢量进 行组合，构成多个三元组，三元组包括的三个已编码块的运动矢量可以作为当前块的候选的控制点运动矢量，所述多个三元组可参见如下公式(13B)、(13C)所示：
{v A2,v B1,v A0},{v A2,v B0,v A0},{v B2,v B1,v A0},{v B2,v B0,v A0},{v B3,v B1,v A0},{v B3,v B0,v A0}(13B)
{v A2,v B1,v A1},{v A2,v B0,v A1},{v B2,v B1,v A1},{v B2,v B0,v A1},{v B3,v B1,v A1},{v B3,v B0,v A1}(13C)
其中，v A2表示A2的运动矢量，v B1表示B1的运动矢量，v B0表示B0的运动矢量，v B2表示B2的运动矢量，v B3表示B3的运动矢量，v A0表示A0的运动矢量，v A1表示A1的运动矢量。
需要说明的是，其他控制点运动矢量的组合的方法也可适用于本发明实施例，此处不做赘述。
需要说明的是，采用其他控制点来表示相邻和当前编码块的运动模型的方法也可以适用于本发明实施例，此处不做赘述。
下面描述基于仿射运动模型的Merge模式的构造的控制点运动矢量预测方法。
以图9所示为例对该构造的控制点运动矢量预测方法进行描述，以利用当前编码块周边邻近的已编码块的运动信息确定当前块左上顶点和右上顶点的运动矢量。需要说明的是，图9仅作为一种示例。
如图9所示，CPk(k＝1,2,3,4)表示第k个控制点。A0,A1,A2,B0,B1,B2和B3为当前块的空域相邻位置，用于预测CP1、CP2或CP3；T为当前块的时域相邻位置，用于预测CP4。假设，CP1,CP2,CP3和CP4的坐标分别为(0,0),(W,0),(H,0)和(W,H)，其中W和H为当前块的宽度和高度。那么对于当前块的每个控制点，其运动信息按照以下顺序获得：
1、对于CP1，检查顺序为B2->A2->B3,如果B2可得，则采用B2的运动信息。否则，检测A2，B3。若三个位置的运动信息均不可得，则无法获得CP1的运动信息。
2、对于CP2，检查顺序为B0->B1；如果B0可得，则CP2采用B0的运动信息。否则，检测B1。若两个位置的运动信息均不可得，则无法获得CP2的运动信息。
3、对于CP3，检测顺序为A0->A1；
4、对于CP4，采用T的运动信息。
此处X可得表示包括X(X为A0,A1,A2,B0,B1,B2,B3或T)位置的块已经编码并且采用帧间预测模式；否则，X位置不可得。需要说明的是，其他获得控制点的运动信息的方法也可适用于本发明实施例，此处不做赘述。
然后，将当前块的控制点的运动信息进行组合，得到构造的控制点运动信息。
若当前块采用的是4参数仿射运动模型，则将当前块的两个控制点的运动信息进行组合构成二元组，用来构建4参数仿射运动模型。两个控制点的组合方式可以为{CP1,CP4},{CP2,CP3},{CP1,CP2},{CP2,CP4},{CP1,CP3},{CP3,CP4}。例如，采用CP1和CP2控制点组成的二元组构建的4参数仿射运动模型，可以记作Affine(CP1,CP2)。
若当前块采用的是6参数仿射运动模型，则将当前块的三个控制点的运动信息进行组合构成三元组，用来构建6参数仿射运动模型。三个控制点的组合方式可以为{CP1,CP2,CP4},{CP1,CP2,CP3},{CP2,CP3,CP4},{CP1,CP3,CP4}。例如，采用CP1、CP2和CP3控制点构成的三元组构建的6参数仿射运动模型，可以记作Affine(CP1,CP2,CP3)。
若当前块采用的是8参数双线性模型，则将当前块的四个控制点的运动信息进行组合构 成的四元组，用来构建8参数双线性模型。采用CP1、CP2、CP3和CP4控制点构成的四元组构建的8参数双线性模型，记做Bilinear(CP1,CP2,CP3,CP4)。
本发明实施例中，为了描述方便，将由两个控制点(或者两个已编码块)的运动信息组合简称为二元组，将三个控制点(或者两个已编码块)的运动信息组合简称为三元组，将四个控制点(或者四个已编码块)的运动信息组合简称为四元组。
按照预置的顺序遍历这些模型，若组合模型对应的某个控制点的运动信息不可得，则认为该模型不可得；否则，确定该模型的参考帧索引，并将控制点的运动矢量进行缩放，若缩放后的所有控制点的运动信息一致，则该模型不合法。若确定控制该模型的控制点的运动信息均可得，并且模型合法，则将该构建该模型的控制点的运动信息加入运动信息候选列表中。
控制点的运动矢量缩放的方法如下公式(14)所示：
Figure PCTCN2019091364-appb-000028
其中，CurPoc表示当前帧的POC号,DesPoc表示当前块的参考帧的POC号,SrcPoc表示控制点的参考帧的POC号，MV s表示缩放得到的运动矢量，MV表示控制点的运动矢量。
需要说明的是，亦可将不同控制点的组合转换为同一位置的控制点。
例如将{CP1,CP4},{CP2,CP3},{CP2,CP4},{CP1,CP3},{CP3,CP4}组合得到的4参数仿射运动模型转换为通过{CP1,CP2}或{CP1,CP2,CP3}来表示。转换方法为将控制点的运动矢量及其坐标信息，代入上述公式(2)，得到模型参数，再将{CP1,CP2}的坐标信息代入上述公式(3)，得到其运动矢量。
更直接地，可以按照以下公式(15)-(23)来进行转换，其中，W表示当前块的宽度，H表示当前块的高度，公式(15)-(23)中，(vx 0，vy 0)表示CP1的运动矢量，(vx 1，vy 1)表示CP2的运动矢量，(vx 2，vy 2)表示CP3的运动矢量，(vx 3，vy 3)表示CP4的运动矢量。
{CP1,CP2}转换为{CP1,CP2,CP3}可以通过如下公式(15)实现，即{CP1,CP2,CP3}中CP3的运动矢量可以通过公式(15)来确定：
Figure PCTCN2019091364-appb-000029
{CP1,CP3}转换{CP1,CP2}或{CP1,CP2,CP3}可以通过如下公式(16)实现：
Figure PCTCN2019091364-appb-000030
{CP2,CP3}转换为{CP1,CP2}或{CP1,CP2,CP3}可以通过如下公式(17)实现：
Figure PCTCN2019091364-appb-000031
{CP1,CP4}转换为{CP1,CP2}或{CP1,CP2,CP3}可以通过如下公式(18)或者(19)实现：
Figure PCTCN2019091364-appb-000032
Figure PCTCN2019091364-appb-000033
{CP2,CP4}转换为{CP1,CP2}可以通过如下公式(20)实现，{CP2,CP4}转换为{CP1,CP2,CP3}可以通过公式(20)和(21)实现：
Figure PCTCN2019091364-appb-000034
Figure PCTCN2019091364-appb-000035
{CP3,CP4}转换为{CP1,CP2}可以通过如下公式(20)实现，{CP3,CP4}转换为{CP1,CP2,CP3}可以通过如下公式(22)和(23)实现：
Figure PCTCN2019091364-appb-000036
Figure PCTCN2019091364-appb-000037
例如将{CP1,CP2,CP4},{CP2,CP3,CP4},{CP1,CP3,CP4}组合的6参数仿射运动模型转换为控制点{CP1,CP2,CP3}来表示。转换方法为将控制点的运动矢量及其坐标信息，代入上述公式(4)，得到模型参数，再将{CP1,CP2,CP3}的坐标信息代入公式上述(5)，得到其运动矢量。
更直接地，可以按照以下公式(24)-(26)进行转换，，其中，W表示当前块的宽度，H表示当前块的高度，公式(24)-(26)中，(vx 0，vy 0)表示CP1的运动矢量，(vx 1，vy 1)表示CP2的运动矢量，(vx 2，vy 2)表示CP3的运动矢量，(vx 3，vy 3)表示CP4的运动矢量。
{CP1,CP2,CP4}转换为{CP1,CP2,CP3}可以通过公式(22)实现：
Figure PCTCN2019091364-appb-000038
{CP2,CP3,CP4}转换为{CP1,CP2,CP3}可以通过公式(23)实现：
Figure PCTCN2019091364-appb-000039
{CP1,CP3,CP4}转换为{CP1,CP2,CP3}可以通过公式(24)实现：
Figure PCTCN2019091364-appb-000040
具体实施例中，将当前所构造的控制点运动信息加入候选运动矢量列表后，若此时候选列表的长度小于最大列表长度(如MaxAffineNumMrgCand)，则按照预置的顺序遍历这些组合，得到合法的组合作为候选的控制点运动信息，如果此时候选运动矢量列表为空， 则将该候选的控制点运动信息加入候选运动矢量列表；否则依次遍历候选运动矢量列表中的运动信息，检查候选运动矢量列表中是否存在与该候选的控制点运动信息相同的运动信息。如果候选运动矢量列表中不存在与该候选的控制点运动信息相同的运动信息，则将该候选的控制点运动信息加入候选运动矢量列表。
示例性的，一种预置的顺序如下：Affine(CP1,CP2,CP3)→Affine(CP1,CP2,CP4)→Affine(CP1,CP3,CP4)→Affine(CP2,CP3,CP4)→Affine(CP1,CP2)→Affine(CP1,CP3)→Affine(CP2,CP3)→Affine(CP1,CP4)→Affine(CP2,CP4)→Affine(CP3,CP4)，总共10种组合。
若组合对应的控制点运动信息不可得，则认为该组合不可得。若组合可得，确定该组合的参考帧索引(两个控制点时，选择参考帧索引最小的作为该组合的参考帧索引；大于两个控制点时，先选择出现次数最多的参考帧索引，若有多个参考帧索引的出现次数一样多，则选择参考帧索引最小的作为该组合的参考帧索引)，并将控制点的运动矢量进行缩放。若缩放后的所有控制点的运动信息一致，则该组合不合法。
可选地，本发明实施例还可以针对候选运动矢量列表进行填充，比如，经过上述遍历过程后，此时候选运动矢量列表的长度小于最大列表长度(如MaxAffineNumMrgCand)，则可以对候选运动矢量列表进行填充，直到列表的长度等于最大列表长度。
可以通过补充零运动矢量的方法进行填充，或者通过将现有列表中已存在的候选的运动信息进行组合、加权平均的方法进行填充。需要说明的是，其他获得候选运动矢量列表填充的方法也可适用于本发明实施例，在此不做赘述。
基于上文的描述，下面进一步描述基于仿射运动模型的AMVP模式(Affine AMVP mode)和基于仿射运动模型的Merge模式(Affine Merge mode)。
首先描述基于仿射运动模型的AMVP模式。
对于基于仿射运动模型的先进运动矢量预测模式，可利用继承的控制点运动矢量预测方法和/或构造的控制点运动矢量预测方法，构建基于仿射运动模型的AMVP模式的候选运动矢量列表。在本发明实施例中可以将基于仿射运动模型的AMVP模式的候选运动矢量列表称为控制点运动矢量预测值候选列表(control point motion vectors predictor candidate list)，列表中的控制点运动矢量预测值包括2个(如当前块为4参数仿射运动模型的情况)候选的控制点运动矢量或者包括3个(如当前块为6参数仿射运动模型的情况)候选的控制点运动矢量。
可能的应用场景中，还可将控制点运动矢量预测值候选列表根据特定的规则进行剪枝和排序，并可将其截断或填充至特定的个数。
然后，在编码端，编码器(如前述编码器20)利用控制点运动矢量预测值候选列表中的每个控制点运动矢量预测值，通过公式(3)或(5)或(7)获得当前编码块中每个子运动补偿单元的运动矢量，进而得到每个子运动补偿单元的运动矢量所指向的参考帧中对应位置的像素值，作为其预测值，进行采用仿射运动模型的运动补偿。计算当前编码块中每个像素点的原始值和预测值之间差值的平均值，选择最小平均值对应的控制点运动矢量预测值为最优的控制点运动矢量预测值，并作为当前编码块2个或3个或4个控制点的运动矢量预测值。 此外在编码端，还以控制点运动矢量预测值作为搜索起始点在一定搜索范围内进行运动搜索获得控制点运动矢量(control point motion vectors，CPMV)，并计算控制点运动矢量与控制点运动矢量预测值之间的差值(control point motion vectors differences，CPMVD)。然后，编码器将表示该控制点运动矢量预测值在控制点运动矢量预测值候选列表中位置的索引号以及CPMVD编码入码流传递到解码端。
在解码端，解码器(如前述解码器30)解析获得码流中的索引号以及控制点运动矢量差值(CPMVD)，根据索引号从控制点运动矢量预测值候选列表中确定控制点运动矢量预测值(control point motion vectors predictor，CPMVP)，将CPMVP与CPMVD相加，得到控制点运动矢量。
接下来描述基于仿射运动模型的Merge模式。
对于基于仿射运动模型的Merge模式，可利用继承的控制点运动矢量预测方法和/或构造的控制点运动矢量预测方法，构建控制点运动矢量融合候选列表(control point motion vectors merge candidate list)。
可能的应用场景中，可将控制点运动矢量融合候选列表根据特定的规则进行剪枝和排序，并可将其截断或填充至特定的个数。
然后，在编码端，编码器(如前述编码器20)利用融合候选列表中的每个控制点运动矢量，通过公式(3)或(5)或(7)获得当前编码块中每个子运动补偿单元(像素点或特定方法划分的大小为N 1×N 2的像素块)的运动矢量，进而得到每个子运动补偿单元的运动矢量所指向的参考帧中位置的像素值，作为其预测值，进行仿射运动补偿。计算当前编码块中每个像素点的原始值和预测值之间差值的平均值，选择差值的平均值最小对应的控制点运动矢量作为当前编码块2个或3个或4个控制点的运动矢量。将表示该控制点运动矢量在候选列表中位置的索引号编码入码流发送给解码端。
在解码端，解码器(如前述解码器30)解析索引号，根据索引号从控制点运动矢量融合候选列表中确定控制点运动矢量(control point motion vectors，CPMV)。
另外，需要说明的是，本发明实施例中，“至少一个”是指一个或者多个，“多个”是指两个或两个以上。“和/或”，描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B的情况，其中A,B可以是单数或者复数。字符“/”一般表示前后关联对象是一种“或”的关系。“以下至少一项(个)”或其类似表达，是指的这些项中的任意组合，包括单项(个)或复数项(个)的任意组合。例如，a,b,或c中的至少一项(个)，可以表示：a,b,c,a-b,a-c,b-c,或a-b-c，其中a,b,c可以是单个，也可以是多个。
在本发明实施例中，编码端可使用语法元素来向解码端指示当前块的帧间预测模式、当前块采用的仿射运动模型以及其他相关信息。
目前所采用的解析当前块采用的帧间预测模式的部分语法结构，可以参见表1所示。需要说明的是，语法结构中的语法元素还可以通过其他标识来表示，本发明实施例对此不作具体限定。
表1
Figure PCTCN2019091364-appb-000041
Figure PCTCN2019091364-appb-000042
表1中，ae(v)表示采用基于自适应二元算术编码(context-based adaptive binary arithmetic coding，cabac)编码的语法元素。
语法元素merge_flag[x0][y0]可用于指示针对当前块是否采用融合模式。比如，当merge_flag[x0][y0]＝1时，指示针对当前块采用融合模式，当merge_flag[x0][y0]＝0时，指示针对当前块不采用融合模式。x0，y0表示当前块在视频图像的坐标。
变量allowAffineMerge可用于指示当前块是否满足采用基于仿射运动模型的merge模式的条件。比如allowAffineMerge＝0，指示不满足采用基于仿射运动模型的merge模式的条件,allowAffineMerge＝1，指示满足采用基于仿射运动模型的merge模式的条件。采用基于仿射运动模型的merge模式的条件可以是：当前块的宽和高中均大于或者等于8。cbWidth表示当前块的宽，cbHeight表示当前块的高，即，当cbWidth<8或cbHeight<8时，allowAffineMerge＝0，当cbWidth>＝8且cbHeight>＝8时，allowAffineMerge＝1。
变量allowAffineInter可用于指示当前块是否满足采用基于仿射运动模型的AMVP模式的条件。比如allowAffineInter＝0，指示不满足采用基于仿射运动模型的AMVP模式的条件，allowAffineInter＝1，指示满足采用基于仿射运动模型的AMVP模式的条件。采用基于仿射运动模型的AMVP模式的条件可以是：当前块的宽和高中均大于或者等于16。即，当cbWidth<16或cbHeight<16时，allowAffineInter＝0，当cbWidth>＝16且cbHeight>＝16时，allowAffineInter＝1。
语法元素affine_merge_flag[x0][y0]可用于指示针对当前块是否采用基于仿射运动模型的merge模式。当前块所在条带的类型(slice_type)为P型或者B型。比如，affine_merge_flag[x0][y0]＝1，指示针对当前块采用基于仿射运动模型的merge模式，affine_merge_flag[x0][y0]＝0，指示针对当前块不采用基于仿射运动模型的merge模式，可以采用平运运动模型的merge模式。
语法元素merge_idx[x0][y0]可用于指示针对merge候选列表的索引值。
语法元素affine_merge_idx[x0][y0]可用于指示针对仿射merge候选列表的索引值。
语法元素affine_inter_flag[x0][y0]可用于指示在当前块所在条带为P型条带或者B型条带时，针对当前块是否采用基于仿射运动模型的AMVP模式。比如，affine_inter_flag[x0][y0]＝0，指示针对当前块采用基于仿射运动模型的AMVP模式，affine_inter_flag[x0][y0]＝1，指示针对当前块不采用基于仿射运动模型的AMVP模式，可以采用平动运动模型的AMVP模式。
语法元素affine_type_flag[x0][y0]可以用于指示：在当前块所在条带为P型条带或者B型条带时，针对当前块是否采用6参数仿射运动模型进行运动补偿。affine_type_flag[x0][y0]＝0，指示针对当前块不采用6参数仿射运动模型进行运动补偿，可以仅采用4参数仿射运动模型进行运动补偿；affine_type_flag[x0][y0]＝1，指示针对当前块采用6参数仿射运动模型进行运动补偿。
变量MaxNumMergeCand、MaxAffineNumMrgCand用于表示最大列表长度，指示构造的候选运动矢量列表的最大长度。inter_pred_idc[x0][y0]用于指示预测方向。PRED_L1用于指示后向预测。num_ref_idx_l0_active_minus1指示前向参考帧列表的参考帧个数，ref_idx_l0[x0][y0]指示当前块的前向参考帧索引值。mvd_coding(x0,y0,0,0)指示第一个运动矢量差。mvp_l0_flag[x0][y0]指示前向MVP候选列表索引值。PRED_L0指示前向预测。num_ref_idx_l1_active_minus1指示后向参考帧列表的参考帧个数。ref_idx_l1[x0][y0]指示当前块的后向参考帧索引值，mvp_l1_flag[x0][y0]表示后向MVP候选列表索引值。
如表2所示，MotionModelIdc[x0][y0]＝1，指示采用4参数仿射运动模型，MotionModelIdc[x0][y0]＝2，指示采用6参数仿射运动模型，MotionModelIdc[x0][y0]＝0指示采用平动运动模型。
表2
Figure PCTCN2019091364-appb-000043
需要说明的是，上述表1和表2仅仅作为实例。在实际应用中，上述表1和表2还可以包括更多或更少的内容，例如表2中MotionModelIdc[x0][y0]还可能包括其他值，该值可用于指示采用8参数双线性模型，等等。
现有做法中，编码端或者解码端在通过帧间预测模式得到当前块的每个子块的运动矢量值后，需要将其存储起来，用于其后续的运动补偿；同时，得到的运动矢量值还将用于后续其他解码流程，例如作为相邻块解码过程中的运动矢量预测、去块效应滤波的滤波强度判决等。而所得到的当前块的控制点的运动矢量也需要存储起来，以供后续相邻的待编解码块利用继承的控制点运动矢量预测方法时使用。故此时，对于当前块，存在两种类别的运动矢量：每个子块的运动矢量，以及，控制点的运动矢量。现有方案中为了避免存储两类运动矢量，会使用控制点的运动矢量覆盖了其所在子块的运动矢量。例如，若当前仿 射解码块采用的仿射运动模型为4仿射运动模型，则将左上角子块、右上角子块的运动矢量设置为左上、右上顶点控制点的运动矢量。若当前仿射解码块采用的仿射运动模型为6仿射运动模型，则将左上角子块、右上角子块、左下角子块的运动矢量设置为左上、右上、左下顶点控制点的运动矢量。该方法虽然该解决了运动矢量存储的问题，但是因为控制点所在的子块使用了与其他子块不一致的运动矢量进行运动补偿，导致了预测不准确，从而降低了编码效率。
为了克服现有技术的缺陷，既解决了运动矢量存储的问题，又提高编解码过程中预测的准确性，提升编码效率，本发明实施例对上文所述继承的控制点运动矢量预测方法进行改进。
本发明实施例提供的改进的继承的控制点运动矢量预测方法在确定当前块的候选的控制点运动矢量过程中，不需要利用到相邻仿射编码块(或相邻仿射解码块)的控制点的运动矢量，而是采用相邻仿射编码块(或相邻仿射解码块)至少两个子块的运动矢量来推导得到当前块的候选的控制点运动矢量。在完成每个相邻仿射编码块(或相邻仿射解码块)的子块运动矢量的推导后，控制点的运动矢量不需要进行存储，即当前块的控制点的运动矢量只用于该当前块的子块的运动矢量的推导，后续将不用于其他待处理相邻块的运动矢量预测。因此，本发明方案只需要保存子块的运动矢量，并且均采用子块的运动矢量进行运动补偿，解决运动矢量存储的问题的同时，还提高了预测的准确性以及编码效率。
其中，相邻仿射编码块为在编码阶段采用仿射运动模型进行预测的与当前块相邻的已编码块，相邻仿射解码块为在解码阶段采用仿射运动模型进行预测的与当前块相邻的已解码块。在本文中，对于当前块，可采用W表述当前块的宽度，H表述当前块的高度。对于相邻仿射解码块，可采用U表述相邻仿射解码块的宽度，V表述相邻仿射解码块的高度。
下面进一步详细描述该改进的继承的控制点运动矢量预测方法的一些具体实施方式。需要说明的是，下文是从解码端的角度对该改进的继承的控制点运动矢量预测方法进行阐述，而关于编码端的改进的继承的控制点运动矢量预测方法可参考该阐述来实现，为了说明书的简洁，将不再赘述。
首先描述相邻仿射解码块为4参数仿射解码块时，该改进的继承的控制点运动矢量预测方法的一些实例。
在一实例中，若相邻仿射解码块为4参数仿射解码块，则获取该相邻仿射解码块中子块中心点的水平坐标距离为P、竖直坐标相同的两个子块的运动矢量及其中心点的坐标，组成4参数仿射运动模型，用来推导当前仿射解码块的控制点的运动矢量，其中P小于该相邻仿射解码块的宽度U，并且P为2的幂次方。
在又一实例中，若相邻仿射解码块为4参数仿射解码块，则获取该相邻仿射解码块中子块中心点的水平坐标相同、竖直坐标距离为Q的两个子块的运动矢量及其中心点的坐标，组成4参数仿射运动模型，用来推导当前仿射解码块的控制点的运动矢量，其中Q小于该相邻仿射解码块的高度V，并且Q为2的幂次方。
接下来描述相邻仿射解码块为6参数仿射解码块时，该改进的继承的控制点运动矢量预测方法的一些实例。
在一实例中，若相邻仿射解码块为6参数仿射解码块，则获取该相邻仿射解码块中子块中心点的水平坐标距离为P、竖直坐标相同的两个子块(如分别称为第一子块和第二子块)的运动矢量及其中心点的坐标，再获取该相邻仿射解码块中子块中心点与第一子块的水平坐标相同、竖直坐标距离为Q的一个子块的运动矢量及其中心点的坐标，组成6参数仿射运动模型，用来推导当前仿射解码块的控制点的运动矢量，其中P小于该相邻仿射解码块的宽度U，并且P为2的幂次方，Q小于该相邻仿射解码块的高度V，并且Q为2的幂次方。
在又一实例中，若相邻仿射解码块为6参数仿射解码块，则获取该相邻仿射解码块中子块中心点的水平坐标距离为P、竖直坐标相同的两个子块(如分别称为第一子块和第二子块)的运动矢量及其中心点的坐标，再获取该相邻仿射解码块中子块中心点与第二子块的水平坐标相同、竖直坐标距离为Q的一个子块的运动矢量及其中心点的坐标，组成6参数仿射运动模型，用来推导当前仿射解码块的控制点的运动矢量，其中P小于该相邻仿射解码块的宽度U，并且P为2的幂次方，Q小于该相邻仿射解码块的高度V，并且Q为2的幂次方。
在又一实例中，不区分相邻仿射解码块的参数类型，直接获取该相邻仿射解码块中子块中心点的水平坐标距离为P、竖直坐标相同的两个子块(如分别称为第一子块和第二子块)的运动矢量及其中心点的坐标，再获取该相邻仿射解码块中子块中心点与第一子块的水平坐标相同、竖直坐标距离为Q的一个子块的运动矢量及其中心点的坐标，组成6参数仿射运动模型，用来推导当前仿射解码块的控制点的运动矢量，其中P小于该相邻仿射解码块的宽度U，并且P为2的幂次方，Q小于该相邻仿射解码块的高度V，并且Q为2的幂次方。
需要说明的是，本发明实施例采用的两个子块中心点的距离为2的幂次方，有利于在进行运动矢量推导时，能够通过移位的方式进行实现，从而降低了实现的复杂度。
还需要说明的是，上述各个实例中采用子块的中心点位置只是为了便于描述，实际应用中，针对相邻仿射解码块采用的子块的坐标位置(可简称为相邻仿射解码块的预设子块位置)需要与编解码中计算该子块的运动矢量时所采用的位置一致(即相邻仿射解码块的子块采用该子块中预设位置像素点的运动矢量来表示该子块内所有像素点的运动矢量)。所以，预设子块位置还可能是多种多样的。比如预设子块位置为相邻仿射解码块的子块内左上角像素点的位置，也就是说，编解码中计算该子块的运动矢量时采用左上像素点进行计算，则上述各个实例同样应该使用采用子块的左上像素点的坐标。又比如，预设子块位置为相邻仿射解码块的子块内距离几何中心位置最近的一个像素点的位置，又比如，预设子块位置为邻仿射解码块的子块内右上角像素点的位置，等等。
为了描述方便，下文的各种实例描述均以子块中心点为例，其他子块位置的实现方式可参考该描述，将不再一一赘述。
在本发明实施例可能的应用场景中，可以对仿射解码块的使用条件进行限制，使得相邻仿射解码块能够在水平方向划分为至少2个子块，在竖直方向划分为至少2个子块。例如，假设子块的尺寸为MxN，M为4、8、16等整数，N为4、8、16等整数，那么，仿射解码块的允许使用尺寸为宽度W≥2M，高度H≥2N。当解码单元相(相邻块)的尺寸不满足仿射解码块的使用条件时，可不需要解析仿射相关的语法元素，如表一中的affine_inter_flag，affine_merge_flag，等等。
在本发明的一个实施例中，若相邻仿射解码块为4参数仿射解码块，如图10所示，假设 当前块的相邻仿射解码块的左上顶点的坐标为(x4,y4)，宽度为U、高度为V、划分的子块尺寸为MxN(如图10中所示的相邻仿射解码块的子块尺寸为4x4)，则获取位置(x4+M/2,y4+N/2)的运动矢量(vx4,vy4)和位置(x4+M/2+P,y4+N/2)的运动矢量(vx5,vy5)组成4参数仿射运动模型。
然后利用如下公式(27)计算获得当前仿射解码块左上控制点(x0,y0)的运动矢量(vx0,vy0)：
Figure PCTCN2019091364-appb-000044
利用公式(28)计算获得当前仿射解码块右上控制点(x1,y1)的运动矢量(vx1,vy1)。可选的，此处(x1,y1)的值可以设置为(x0+W,y0)，W为当前块的宽度。
Figure PCTCN2019091364-appb-000045
可选的(如当前块为6参数仿射解码块)，利用公式(29)计算获得当前仿射解码块左下控制点(x2,y2)的运动矢量(vx2,vy2)。可选的，此处(x2,y2)的值可以设置为(x0,y0+H)，其中H为当前块的高度。
Figure PCTCN2019091364-appb-000046
在本发明的一个实施例中，若相邻仿射解码块为6参数仿射解码块，同样以图10所示为例，当前块的相邻仿射解码块的左上顶点的坐标为(x4,y4)，宽度为U、高度为V、划分的子块尺寸为MxN(如图10中所示的相邻仿射解码块的子块尺寸为4x4)，则获取位置(x4+M/2,y4+N/2)的运动矢量(vx4,vy4)、位置(x4+M/2+P,y4+N/2)的运动矢量(vx5,vy5)和位置(x4+M/2,y4+N/2+Q)的运动矢量(vx6,vy6)组成6参数仿射运动模型。
然后，利用如下公式(30)计算获得当前仿射解码块左上控制点(x0,y0)的运动矢量(vx0,vy0)：
Figure PCTCN2019091364-appb-000047
利用公式(31)计算获得当前仿射解码块右上控制点(x1,y1)的运动矢量(vx1,vy1)。可选的，此处(x1,y1)的值可以设置为(x0+W,y0)，W为当前块的宽度。
Figure PCTCN2019091364-appb-000048
可选的(如当前块为6参数仿射解码块)，利用公式(32)计算获得当前仿射解码块左下控制点(x2,y2)的运动矢量(vx2,vy2)。可选的，此处(x2,y2)的值可以设置为(x0,y0+H)，其中H为当前块的高度。
Figure PCTCN2019091364-appb-000049
需要说明的是，本发明实施例的方法也可以不限定条件，应用于所有相邻仿射解码块。即，均采用三个子块的运动矢量，组成6参数仿射运动模型进行推导。
需要说明的是，本发明实施例中，因为编解码块的宽度U、高度V通常为2的幂次方，所以此时P的取值可以为U/2，Q的取值可以为V/2。如U为8、16、32、64、128等时，P分别为4、8、16、32、64等；如V为8、16、32、64、128等时，Q分别为4、8、16、32、64等。
需要说明的是，上述实施例仅仅作为示例，本发明其他实施例也可以采用其他中心点水平距离为P的两个子块，竖直距离为Q的两个子块，这里不再赘述。
另外，在实际实现中，由于P、Q均为2的幂次方，因此上述公式(27)-公式(32)的除法操作可以通过右移的方式实现。同时，为了降低除法的精度损失，可以将上述公式(27)-公式(32)的等式两端都进行左移放大，最后再进行右移。
具体实现操作可以按照以下流程，其中，Log2为取2的对数的函数，<<表示左移位，>>表示右移位：
log2P＝Log2(P)
log2Q＝Log2(Q)
mvScaleHor＝vx4<<7
mvScaleVer＝vy4<<7
dHorX＝(vx5–vx4)<<(7–log2P)
dVerX＝(vy5–vy4)<<(7–log2Q)
若相邻仿射解码块为6参数仿射解码块，则令：
dHorY＝(vx6–vx4)<<(7–log2P)
dVerY＝(vy6–vy4)<<(7–log2Q)
若相邻仿射解码块为4参数仿射解码块，则令：
dHorY＝–dVerX
dVerY＝dHorX
接着，当前仿射解码块的控制点的运动矢量可以按照以下公式计算：
vx0＝Round(mvScaleHor+dHorX*(x0–x4–M/2)+dHorY*(y0–y4–N/2))
vy0＝Round(mvScaleVer+dVerX*(x0–x4–M/2)+dVerY*(y0–y4–N/2))
vx1＝Round(mvScaleHor+dHorX*(x1–x4–M/2)+dHorY*(y1–y4–N/2))
vy1＝Round(mvScaleVer+dVerX*(x1–x4–M/2)+dVerY*(y1–y4–N/2))
vx2＝Round(mvScaleHor+dHorX*(x2–x4–M/2)+dHorY*(y2–y4–N/2))
vy2＝Round(mvScaleVer+dVerX*(x2–x4–M/2)+dVerY*(y2–y4–N/2))
其中Round函数的操作如下，对于任意输入K，其输出K通过以下方式获得：
mvShift＝7
offset＝1<<(mvShift–1)
K＝K>＝0？(K+offset)>>mvShift:–((–K+offset)>>mvShift)
在本发明的又一个实施例中，若相邻仿射解码块位于当前仿射解码块的上方CTU，为了减少内存读取，可以获取该相邻仿射解码块的位于CTU最下方的两个子块的运动矢量进行推导。假设该相邻仿射解码块的左上顶点的坐标为(x4,y4)，宽度为U、高度为V、划分的子块尺寸为MxN，则获取位置(x4+M/2,y4+V–N/2)的运动矢量(vx4,vy4)，位置(x4+M/2+P,y4+V–N/2)的运动矢量(vx5,vy5)组成4参数仿射运动模型。
然后，利用如下公式(33)计算获得当前仿射解码块左上控制点(x0,y0)的运动矢量(vx0,vy0)：
Figure PCTCN2019091364-appb-000050
利用如下公式(34)计算获得当前仿射解码块右上控制点(x1,y1)的运动矢量(vx1,vy1)：
Figure PCTCN2019091364-appb-000051
利用如下公式(35)计算获得当前仿射解码块左下控制点(x2,y2)的运动矢量(vx2,vy2)：
Figure PCTCN2019091364-appb-000052
需要说明的是，本发明实施例的方法也可以不限定条件，都应用于相邻仿射解码块为4参数仿射解码块的情况。即，若相邻仿射解码块为4参数仿射解码块，均采用最下方的两个中心点距离为P的子块的运动矢量进行推导。
在本发明的另一个实施例中，若相邻仿射解码块位于当前仿射解码块的左方CTU，为了减少内存读取，可以获取该相邻仿射解码块的位于CTU最右方的两个子块的运动矢量进行推导。假设该相邻仿射解码块的左上顶点的坐标为(x4,y4)，宽度为U、高度为V、划分的子块尺寸为MxN，则获取位置(x4+U–M/2,y4+N/2)的运动矢量(vx4,vy4)，位置(x4+U–M/2,y4+N/2+Q)的运动矢量(vx5,vy5)组成4参数仿射运动模型。
然后，利用如下公式(36)计算获得当前仿射解码块左上控制点(x0,y0)的运动矢量(vx0,vy0)：
Figure PCTCN2019091364-appb-000053
利用如下公式(37)计算获得当前仿射解码块右上控制点(x1,y1)的运动矢量(vx1,vy1)：
Figure PCTCN2019091364-appb-000054
利用如下公式(38)计算获得当前仿射解码块左下控制点(x2,y2)的运动矢量(vx2,vy2)：
Figure PCTCN2019091364-appb-000055
需要说明的是，本发明实施例的方法也可以不限定条件，都应用于相邻仿射解码块为4参数仿射解码块的情况。即，若相邻仿射解码块为4参数仿射解码块，均采用最右方的两个中心点距离为Q的子块的运动矢量进行推导。
在本发明的又一个实施例中，若相邻仿射解码块位于当前仿射解码块的上方CTU，且该相邻仿射解码块为6参数仿射解码块，为了减少内存读取，可以获取该相邻仿射解码块的位于CTU最下方的两个子块的运动矢量及一个上方的子块的运动矢量进行推导。假设该相邻仿射解码块的左上顶点的坐标为(x4,y4)，宽度为U、高度为V、划分的子块尺寸为MxN，则获取位置(x4+M/2,y4+V–N/2)的运动矢量(vx4,vy4)、位置(x4+M/2+P,y4+V–N/2)的运动矢量(vx5,vy5)、位置(x4+M/2,y4+V–N/2–Q)的运动矢量(vx6,vy6)组成6参数仿射运动模型。
然后，利用如下公式(39)计算获得当前仿射解码块左上控制点(x0,y0)的运动矢量(vx0,vy0)：
Figure PCTCN2019091364-appb-000056
利用如下公式(40)计算获得当前仿射解码块右上控制点(x1,y1)的运动矢量(vx1,vy1)：
Figure PCTCN2019091364-appb-000057
利用如下公式(41)计算获得当前仿射解码块左下控制点(x2,y2)的运动矢量(vx2,vy2)：
Figure PCTCN2019091364-appb-000058
需要说明的是，本发明实施例的方法也可以不限定条件，都应用于相邻仿射解码块为6参数仿射解码块的情况。即，若相邻仿射解码块为6参数仿射解码块，均采用最下方的两个中心点距离为P的子块的运动矢量及距离该最下方子块竖直距离为Q的子块的运动矢量进行推导。
需要说明的是，本发明实施例的方法也可以不限定条件，应用于所有相邻仿射解码块。即，均采用最下方的两个中心点距离为P的子块的运动矢量及距离该最下方子块竖直距离为Q的子块的运动矢量进行推导。
在本发明的又一个实施例中，若相邻仿射解码块位于当前仿射解码块的左方CTU，且该相邻仿射解码块为6参数仿射解码块，为了减少内存读取，可以获取该相邻仿射解码块的位于CTU最右方的两个子块的运动矢量及一个左方的子块的运动矢量进行推导。假设该相邻仿射解码块的左上顶点的坐标为(x4,y4)，宽度为U、高度为V、划分的子块尺寸为MxN，则获取位置(x4+U–M/2,y4+N/2)的运动矢量(vx4,vy4)，位置(x4+U–M/2,y4+N/2+Q)的运动矢量(vx5,vy5)，位置(x4+U–M/2–P,y4+N/2)的运动矢量(vx6,vy6)组成6参数仿射运动模型。
然后，利用如下公式(42)计算获得当前仿射解码块左上控制点(x0,y0)的运动矢量(vx0,vy0)：
Figure PCTCN2019091364-appb-000059
利用如下公式(43)计算获得当前仿射解码块右上控制点(x1,y1)的运动矢量(vx1,vy1)：
Figure PCTCN2019091364-appb-000060
利用如下公式(44)计算获得当前仿射解码块左下控制点(x2,y2)的运动矢量(vx2,vy2)：
Figure PCTCN2019091364-appb-000061
需要说明的是，本发明实施例的方法也可以不限定条件，都应用于相邻仿射解码块为6参数仿射解码块的情况。即，若相邻仿射解码块为6参数仿射解码块，均采用最右方的两个中心点距离为Q的子块的运动矢量及距离该最右方子块水平距离为P的子块的运动矢量进行推导。
需要说明的是，本发明实施例的方法也可以不限定条件，应用于所有相邻仿射解码块。即，均采用最右方的两个中心点距离为Q的子块的运动矢量及距离该最右方子块水平距离为P的子块的运动矢量进行推导。
基于所述改进的继承的控制点运动矢量预测方法，下面进一步本发明实施例提供的基于仿射运动模型的运动矢量预测方法，从编码端或解码端的角度进行描述，参见图11，该方法包括但不限于以下步骤：
步骤701：获取待处理图像块的一个空域参考块。
其中，待处理图像块为通过对视频图像进行分割而得到的，空域参考块为与所述待处理图像块空域相邻的已解码块。在编码端，待处理图像块又可称为当前仿射编码块，空域参考块又可称为相邻仿射编码块；在解码端，待处理图像块又可称为当前仿射解码块，空域参考块又可称为相邻仿射解码块。为了便于描述，本实施例可将待处理图像块统称为当前块，将空域参考块统称为相邻块。
具体实施例中，可按照预设顺序确定当前块的一个或多个预设空域位置的候选参考块的可用性，然后，获得在所述预设顺序中第一个可用的候选参考块作为所述空域参考块。其中，所述预设空域位置的候选参考块包括：位于所述待处理图像块正上方、正左方、右上方、左下方和左上方的相邻图像块。比如，按照正左方相邻图像块、正上方相邻图像块、右上方相邻图像块、左下方相邻图像块、左上方相邻图像块的顺序依次检查所述候选参考块的可用性，直到确定所述第一个可用的候选参考块。
例如以图7为例，可按照图7中A1→B1→B0→A0→B2的顺序遍历当前块周围的相邻位置块，找到相邻位置块所在的相邻块。
具体实施例中，可根据以下方法来确定候选参考块是否可用：当所述候选参考块与所述待处理图像块位于同一图像区域内，并且所述候选参考块基于所述仿射运动模型获得运动矢量时，确定所述候选参考块可用。
步骤702：确定所述空域参考块中两个或两个以上的预设子块位置。
具体的，可确定所述空域参考块中两个或两个以上的子块，每个子块都有相应的预设子块位置，该预设子块位置与编解码中计算该子块的运动矢量时所采用的位置一致，即相 邻仿射解码块的子块采用该子块中预设位置像素点的运动矢量来表示该子块内所有像素点的运动矢量，该预设位置像素点的运动矢量可用于后续的运动补偿，以实现对预设位置像素点所在子块的预测。
具体实现中，预设子块位置可以是子块内左上角像素点的位置；或者，子块的几何中心的位置，或者，子块内距离几何中心位置最近的一个像素点的位置；或者子块内右上角像素点的位置，等等。
具体实施例中，可确定所述空域参考块中两个子块，两个子块对应的两个预设子块位置之间的距离为S，S为2的K次幂，K为非负整数，这样有利于后续在进行运动矢量推导时，能够通过移位的方式进行实现，从而降低了实现的复杂度。
在一实例中，如果当前块的仿射运动模型为4参数仿射运动模型，那么所述空域参考块的多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)和第二预设位置(x4+M/2+P,y4+N/2)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，P为2的K次幂，K为非负整数，K小于U，U为所述空域参考块的宽度。
在一实例中，如果当前块的仿射运动模型为4参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)和第三预设位置(x4+M/2,y4+N/2+Q)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，Q为2的R次幂，R为非负整数，Q小于V，V为所述空域参考块的高度。
在一实例中，如果当前块的仿射运动模型为6参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)，第二预设位置(x4+M/2+P,y4+N/2)和第三预设位置(x4+M/2,y4+N/2+Q)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，P为2的K次幂，Q为2的R次幂，K和R为非负整数，P小于U，Q小于V,U为所述空域参考块的宽度,V为所述空域参考块的高度。
在又一实例中，如果当前块的上边缘所在的直线和当前块所在的编码树单元(CTU)的上边缘所在的直线重合，且所述空域参考块位于所述待处理图像块的正上方、左上方或右上方时，所述多个预设子块位置对应的子块中的至少两个子块与当前块的上边缘邻接。
在又一实例中，如果当前块的左边缘所在的直线和当前块所在的编码树单元(CTU)的左边缘所在的直线重合，且所述空域参考块位于当前块的正左方、左上方或左下方时，所述多个预设子块位置对应的子块中的至少两个子块与当前块的左边缘邻接。
步骤703：根据所述预设子块位置对应的运动矢量，插值计算出所述待处理图像块预设像素点位置对应的运动矢量。
本发明实施例中，采用改进的继承的控制点运动矢量预测方法在确定当前块的候选的控制点运动矢量，即采用相邻仿射编码块(或相邻仿射解码块)至少两个子块的运动矢量来，通过插值计算得到当前块的预设像素点位置的运动矢量，预设像素点位置即为当前块的控制点，比如，如果当前块的仿射运动模型为4参数仿射运动模型，那么当前块的控制点 可为子块内左上角像素点和右上角像素点。如果当前块的仿射运动模型为6参数仿射运动模型，那么当前块的控制点可为子块内左上角像素点、右上角像素点以及左下角像素点，等等。
关于改进的继承的控制点运动矢量预测方法的详细内容已在前文做了详细描述，可参考该内容来实施本实施例，为了说明书的简洁，这里不再赘述。
步骤704：根据所述预设像素点位置对应的运动矢量，插值计算出所述待处理图像块中多个子块位置对应的运动矢量。
具体的，对于当前块的每一个子块(一个子块也可以等效为一个运动补偿单元，子块的宽和高小于当前块的宽和高)，可采用运动补偿单元中预设位置像素点的运动信息来表示该运动补偿单元内所有像素点的运动信息。假设运动补偿单元的尺寸为MxN，则预设位置像素点可以为运动补偿单元中心点(M/2,N/2)、左上像素点(0,0)，右上像素点(M-1,0)，或其他位置的像素点。那么，根据当前块的控制点运动信息以及当前采用的仿射运动模型，可获得当前块中每个子块的运动矢量值，后续可根据所述子块的运动矢量值进行运动补偿得到该子块的像素预测值。
需要说明的是，图11实施例在解码端和编码端的详细实现过程还可参考后续图12实施例和图14实施例的描述，为了说明书的简洁，这里不再赘述。
可以看到，本发明实施例采用了改进继承的控制点运动矢量预测方法，该改进的继承的控制点运动矢量预测方法不需要利用到相邻块控制点的运动矢量，而是采用相邻块至少两个子块的运动矢量，推导当前块的控制点的运动矢量，进而根据控制点的运动矢量推导得到当前块的各个子块的运动矢量，通过运动补偿实现对当前块的预测。当前块的控制点的运动矢量后续将不需要进行存储，即当前块的控制点的运动矢量只用于该当前解码块的子块的运动矢量的推导，不用于相邻块的运动矢量预测。因此，本发明方案只需要保存子块的运动矢量，并且均采用子块的运动矢量进行运动补偿，解决运动矢量存储的问题的同时，避免了控制点所在的子块使用了与其他子块不一致的运动矢量进行运动补偿，提高了预测的准确性。
基于所述改进的继承的控制点运动矢量预测方法，下面进一步本发明实施例提供的基于仿射运动模型的运动矢量预测方法，从解码端的角度进行描述，参见图12，该方法包括但不限于以下步骤：
步骤801：解析码流，确定当前块的帧间预测模式。
具体的，可基于表1所示的语法结构，解析码流，从而确定当前块的帧间预测模式。
若确定当前块的帧间预测模式为基于仿射运动模型的AMVP模式，即，语法元素merge_flag＝0且affine_inter_flag＝1，指示当前块的帧间预测模式为基于仿射运动模型的AMVP模式，则后续执行步骤802a-步骤806a。
若确定当前块的帧间预测模式为基于仿射运动模型的merge模式，即，语法元素merge_flag＝1且affine_merge_flag＝1，指示当前块的帧间预测模式为基于仿射运动模型的Merge模式，则后续执行步骤802b-步骤805b。
步骤802a：构造基于仿射运动模型的AMVP模式对应的候选运动矢量列表。
本发明实施例中，可基于改进的继承的控制点运动矢量预测方法和/或构造的控制点运动矢量预测方法，得到当前块的候选的控制点运动矢量来加入到AMVP模式对应的候选运动矢量列表。
其中，改进的继承的控制点运动矢量预测方法在确定当前块的候选的控制点运动矢量过程中，采用相邻仿射解码块至少两个子块的运动矢量来推导得到当前块的候选的控制点运动矢量预测值(候选运动矢量二元组/三元组/四元组)，来加入候选运动矢量列表。
如果当前块采用4参数仿射运动模型，那么候选运动矢量列表可以包括二元组列表，二元组列表中包括一个或者多个用于构造4参数仿射运动模型的二元组。
如果当前块采用6参数仿射运动模型，那么候选运动矢量列表可以包括三元组列表，三元组列表中包括一个或者多个用于构造6参数仿射运动模型的三元组。
如果当前块采用8参数双线性模型，那么候选运动矢量列表可以包括四元组列表，四元组列表中包括一个或者多个用于构造8参数双线性模型的四元组
在可能的应用场景中，可将候选运动矢量二元组/三元组/四元组列表根据特定的规则进行剪枝和排序，并可将其截断或填充至特定的个数。
对于改进的继承的控制点运动矢量预测方法，例如以图7为例，可按照图7中A1→B1→B0→A0→B2的顺序遍历当前块周围的相邻位置块，找到相邻位置块所在的仿射解码块，采用相邻仿射解码块至少两个子块的运动矢量来构造仿射运动模型，进而推导得到当前块的候选的控制点运动矢量(候选运动矢量二元组/三元组/四元组)，加入到候选运动矢量列表。需要说明的是，其他查找顺序也可以适用于本发明实施例，在此不做赘述。
关于改进的继承的控制点运动矢量预测方法的详细内容可参考前文的相关描述，为了说明书的简洁，这里不再赘述。
另外，关于基于仿射运动模型的AMVP模式的构造的控制点运动矢量预测方法的内容也在前文4)中做了详细描述，为了说明书的简洁，这里也不再赘述。
步骤803a：解析码流，确定最优的控制点运动矢量预测值。
具体的，通过解析码流获得候选运动矢量列表的索引号，根据该索引号从上述步骤602a构建的候选运动矢量列表中确定最优的控制点运动矢量预测值。
例如，若当前解码块采用的仿射运动模型是4参数仿射运动模型(MotionModelIdc为1)，则解析获得索引号，示例性的，索引号为mvp_l0_flag或mvp_l1_flag，根据索引号从候选运动矢量列表中确定2个控制点的最优运动矢量预测值。
又例如，若当前解码块采用的仿射运动模型是6参数仿射运动模型(MotionModelIdc为2)，则解析获得索引号，根据索引号从候选运动矢量列表中确定3个控制点的最优运动矢量预测值。
又例如，若当前解码块采用的仿射运动模型是8参数双线性模型，则解析获得索引号，根据索引号从候选运动矢量列表中确定4个控制点的最优运动矢量预测值。
步骤804a：解析码流，确定控制点的运动矢量。
具体的，通过解析码流获得控制点的运动矢量差值，然后根据控制点的运动矢量差值以及上述步骤803a所确定的最优的控制点运动矢量预测值，得到控制点的运动矢量。
例如，当前解码块采用的仿射运动模型是4参数仿射运动模型(MotionModelIdc为1)， 以前向预测为例，2个控制点的运动矢量差值别为mvd_coding(x0,y0,0,0)和mvd_coding(x0,y0,0,1)。从码流中解码得到当前块的2个控制点的运动矢量差值，示例性的，可从码流中解码得到左上位置控制点和右上位置控制点的运动矢量差值。然后分别使用各控制点的运动矢量差值和运动矢量预测值相加，获得控制点的运动矢量值，即得到当前块左上位置控制点和右上位置控制点的运动矢量值。
又例如，当前解码块仿射运动模型是6参数仿射运动模型(MotionModelIdc为2)，以前向预测为例，3个控制点的运动矢量差分别为mvd_coding(x0,y0,0,0)和mvd_coding(x0,y0,0,1)、mvd_coding(x0,y0,0,2)。从码流中解码得到当前块的3个控制点的运动矢量差，示例性的，从码流中解码得到左上控制点、右上控制点和左下控制点的运动矢量差值。然后，分别使用各控制点的运动矢量差值和运动矢量预测值相加，获得控制点的运动矢量值，即得到当前块左上控制点、右上控制点和左下控制点的运动矢量值。
需要说明的是，本发明实施例还可以是其他仿射运动模型和其他控制点位置，在此不做赘述。
步骤805a：根据控制点的运动矢量以及当前块采用的仿射运动模型获得当前块中每个子块的运动矢量值。
对于当前仿射解码块的每一个子块(一个子块也可以等效为一个运动补偿单元，子块的宽和高小于当前块的宽和高)，可采用运动补偿单元中预设位置像素点的运动信息来表示该运动补偿单元内所有像素点的运动信息。假设运动补偿单元的尺寸为MxN，则预设位置像素点可以为运动补偿单元中心点(M/2,N/2)、左上像素点(0,0)，右上像素点(M-1,0)，或其他位置的像素点。
下面以运动补偿单元中心点为例说明，参见图13，参见图13示出了当前仿射解码块以及运动补偿单元(子块)，图示中每个小方框表示一个运动补偿单元。图13中V0表示当前仿射解码块的左上控制点的运动矢量，V1表示当前仿射解码块的右上控制点的运动矢量，V2表示当前仿射解码块的左下控制点的运动矢量。
运动补偿单元中心点相对于当前仿射解码块左上顶点像素的坐标可使用如下公式(45)计算得到：
Figure PCTCN2019091364-appb-000062
其中i为水平方向第i个运动补偿单元(从左到右)，j为竖直方向第j个运动补偿单元(从上到下)，(x (i,j),y (i,j))表示第(i,j)个运动补偿单元中心点相对于当前仿射解码块左上控制点像素的坐标。
若当前仿射解码块采用的仿射运动模型为6参数仿射运动模型，将(x (i,j),y (i,j))代入6参数仿射运动模型公式(46)，获得每个运动补偿单元中心点的运动矢量，作为该运动补偿单元内所有像素点的运动矢量(vx (i,j),vy (i,j))：
Figure PCTCN2019091364-appb-000063
若当前仿射解码块采用的仿射运动模型为4仿射运动模型，将(x (i,j),y (i,j))代入4参数仿 射运动模型公式(47)，获得每个运动补偿单元中心点的运动矢量，作为该运动补偿单元内所有像素点的运动矢量(vx (i,j),vy (i,j))：
Figure PCTCN2019091364-appb-000064
步骤806a：针对每个子块根据确定的子块的运动矢量值进行运动补偿得到该子块的像素预测值。
步骤802b：构造基于仿射运动模型的merge模式的运动信息候选列表。
本发明实施例中，可基于改进的继承的控制点运动矢量预测方法和/或构造的控制点运动矢量预测方法，得到当前块的候选的控制点运动矢量来加入到merge模式对应的候选运动矢量列表。
其中，改进的继承的控制点运动矢量预测方法在确定当前块的候选的控制点运动矢量过程中，采用相邻仿射解码块至少两个子块的运动矢量来推导得到当前块的候选的控制点运动矢量(候选运动矢量二元组/三元组/四元组)，来加入候选运动矢量列表。
可能的应用场景中，可将运动信息候选列表根据特定的规则进行剪枝和排序，并可将其截断或填充至特定的个数。
例如以图8为例，可根据A1→B1→B0→A0→B2的顺序遍历当前块周边的相邻位置块，找到该相邻位置块所在的仿射编码块，采用相邻仿射解码块至少两个子块的运动矢量来构造仿射运动模型，进而推导得到当前块的候选的控制点运动矢量(候选运动矢量二元组/三元组/四元组)，加入到候选运动矢量列表。需要说明的是，其他查找顺序也可以适用于本发明实施例，在此不做赘述。
具体的，在上述遍历过程中，如果候选运动矢量列表为空，则将该候选的控制点运动信息加入候选列表；否则，继续依次遍历候选运动矢量列表中的运动信息，检查候选运动矢量列表中是否存在与该候选的控制点运动信息相同的运动信息。如果候选运动矢量列表中不存在与该候选的控制点运动信息相同的运动信息，则将该候选的控制点运动信息加入候选运动矢量列表。
其中，判断两个候选运动信息是否相同需要依次判断它们的前后向参考帧、以及各个前后向运动矢量的水平和竖直分量是否相同。只有当以上所有元素都不相同时才认为这两个运动信息是不同的。
如果候选运动矢量列表中的运动信息个数达到最大列表长度MaxAffineNumMrgCand(MaxAffineNumMrgCand为正整数，如1，2，3，4，5等)，则候选列表构建完毕，否则遍历下一个相邻位置块。
关于改进的继承的控制点运动矢量预测方法的内容可参考前文的详细描述，为了说明书的简洁，这里不再赘述。
另外，关于基于仿射运动模型的Merge模式的构造的控制点运动矢量预测方法的内容也在前文4)中做了详细描述，为了说明书的简洁，这里也不再赘述。
步骤S803b：解析码流，确定最优的控制点运动信息。
具体的，通过解析码流获得候选运动矢量列表的索引号，根据该索引号从上述步骤802b 构建的候选运动矢量列表中确定最优的控制点运动信息。
步骤804b：根据最优的控制点运动信息以及当前解码块采用的仿射运动模型获得当前块中每个子块的运动矢量值。本步骤的详细实施可参考上述步骤805a的描述，为了说明书的简洁，这里不再赘述。
步骤805b：针对每个子块根据确定的子块的运动矢量值进行运动补偿得到该子块的像素预测值。
可以看到，本发明实施例中，采用了改进的继承的控制点运动矢量预测方法，由于该改进的继承的控制点运动矢量预测方法不需要利用到相邻块控制点的运动矢量，而是采用相邻仿射解码块至少两个子块的运动矢量，在完成每个仿射解码块的子块运动矢量的推导后，控制点的运动矢量不需要进行存储，即当前解码块的控制点的运动矢量只用于该当前解码块的子块的运动矢量的推导，不用于相邻块的运动矢量预测。因此，本发明方案只需要保存子块的运动矢量，并且均采用子块的运动矢量进行运动补偿，解决运动矢量存储的问题的同时，还提高了预测的准确性。
基于所述改进的继承的控制点运动矢量预测方法，下面进一步本发明实施例提供的基于仿射运动模型的运动矢量预测方法，从编码端的角度进行描述，参见图14，该方法包括但不限于以下步骤：
步骤901：确定当前块的帧间预测模式。
在一具体实现中，对于编码端的帧间预测中，也可预设多种帧间预测模式，所述多种帧内预测模式中例如包括上文所描述的基于仿射运动模型的AMVP模式以及基于仿射运动模型的merge模式，编码端遍历所述多种帧间预测模式，从而确定对当前块的预测最优的帧间预测模式。
在又一具体实现中，对于编码端的帧间预测中，也可只预设一种帧间预测模式，即在这种情况下编码端直接确定当前采用的是默认的帧间预测模式，该默认的帧间预测模式为基于仿射运动模型的AMVP模式或者基于仿射运动模型的merge模式。
本发明实施例中，如果确定当前块的帧间预测模式为基于仿射运动模型的AMVP模式，则后续执行步骤902a-步骤904a。
本发明实施例中，如果确定当前块的帧间预测模式为基于仿射运动模型的AMVP模式，则后续执行步骤902b-步骤904b。
步骤902a：构造基于仿射运动模型的AMVP模式对应的候选运动矢量列表。
本发明实施例中，可基于改进的继承的控制点运动矢量预测方法和/或构造的控制点运动矢量预测方法，得到当前块的候选的控制点运动矢量预测值(如候选运动矢量二元组/三元组/四元组)来加入到AMVP模式对应的候选运动矢量列表。
本步骤的具体实施可参考前述实施例步骤802a的描述，这里不再赘述。
步骤903a：根据率失真代价，确定最优的控制点运动矢量预测值。
在一实例中，编码端可利用候选运动矢量列表中的控制点运动矢量预测值(如候选运动矢量二元组/三元组/四元组)，通过公式(3)或(5)或(7)获得当前块中每个子运动补偿单元的运动矢量，进而得到每个子运动补偿单元的运动矢量所指向的参考帧中对应位置的像素值， 作为其预测值，进行采用仿射运动模型的运动补偿。计算当前编码块中每个像素点的原始值和预测值之间差值的平均值，选择最小平均值对应的控制点运动矢量预测值为最优的控制点运动矢量预测值，并作为当前块2个或3个或4个控制点的运动矢量预测值。
步骤904a：将索引值、控制点的运动矢量差值以及帧间预测模式的指示信息编入码流。
在一实例中，解码端可使用最优的控制点运动矢量预测值作为搜索起始点在一定搜索范围内进行运动搜索获得控制点运动矢量(control point motion vectors，CPMV)，并计算控制点运动矢量与控制点运动矢量预测值之间的差值(control point motion vectors differences，CPMVD)，然后，编码端将表示该控制点运动矢量预测值在候选运动矢量列表中位置的索引值以及CPMVD编码入码流，还可将帧间预测模式的指示信息编入码流，以便于后续传递到解码端。
具体实现中，编入码流的语法元素还可参考前述表1和表2的描述，这里不再赘述。
步骤902b：构造基于仿射运动模型的Merge模式对应的候选运动矢量列表。
本发明实施例中，可基于改进的继承的控制点运动矢量预测方法和/或构造的控制点运动矢量预测方法，得到当前块的候选的控制点运动矢量预测值(如候选运动矢量二元组/三元组/四元组)来加入到Merge模式对应的候选运动矢量列表。
本步骤的具体实施可参考前述实施例步骤802b的描述，这里不再赘述。
步骤903b：根据率失真代价，确定最优的控制点运动信息。
在一实例中，编码端可利用候选运动矢量列表中的控制点运动矢量(如候选运动矢量二元组/三元组/四元组)，通过公式(3)或(5)或(7)获得当前编码块中每个子运动补偿单元的运动矢量，进而得到每个子运动补偿单元的运动矢量所指向的参考帧中位置的像素值，作为其预测值，进行仿射运动补偿。计算当前编码块中每个像素点的原始值和预测值之间差值的平均值，选择差值的平均值最小对应的控制点运动矢量为最优的控制点运动矢量，该最优的控制点运动矢量即作为当前编码块2个或3个或4个控制点的运动矢量。
步骤904b：将索引值以及帧间预测模式的指示信息编入码流。
在一实例中，解码端可将表示该控制点运动矢量在候选列表中位置的索引值编码入码流，帧间预测模式的指示信息编入码流，以便于后续传递到解码端。
具体实现中，编入码流的语法元素还可参考前述表1和表2的描述，这里不再赘述。
需要说明的是，上述实施例仅仅描述了编码端实现编码和码流发送的过程，根据前文的描述，本领域技术人员理解编码端还可以在其他环节实施本发明实施例所描述的其他方法。例如在编码端在对当前块的预测中，对当前块的重构过程的具体实现可参考前文在解码端描述的相关方法(如图12实施例)，在这里不再赘述。
可以看到，本发明实施例中，采用了改进的继承的控制点运动矢量预测方法，由于该改进的继承的控制点运动矢量预测方法不需要利用到相邻仿射编码块控制点的运动矢量，而是采用相邻仿射编码块至少两个子块的运动矢量，从而根据至少两个子块的运动矢量推导得到当前块的控制点候选运动矢量并建立列表，获取最优的控制点候选运动矢量，并将其对应在列表中的索引值发送至解码端，控制点的运动矢量不需要进行存储，即当前编码块的控制点的运动矢量只用于该当前编码块的子块的运动矢量的推导，后续不用于相邻块的运动矢量预测。因此，本发明方案只需要保存子块的运动矢量，并且均采用子块的运动 矢量进行运动补偿，解决运动矢量存储的问题的同时，还提高了预测的准确性。
基于与上述方法相同的发明构思，本发明实施例还提供了一种设备1000，该设备1000包括参考块获取模块1001、子块确定模块1002、第一计算模块1003和第二计算模块1004，其中：
参考块获取模块1001，用于获取所述视频数据中的待处理图像块的一个空域参考块；
子块确定模块1002，用于确定所述空域参考块中多个预设子块位置；
第一计算模块1003，用于根据所述预设子块位置对应的运动矢量，插值计算出所述待处理图像块预设像素点位置对应的运动矢量；
第二计算模块1004，用于根据所述预设像素点位置对应的运动矢量，插值计算出所述待处理图像块中多个子块位置对应的运动矢量。
在可能的实施例中，所述参考块获取模块1001具体用于：按照预设顺序确定所述待处理图像块的一个或多个预设空域位置的候选参考块的可用性；获得在所述预设顺序中第一个可用的候选参考块作为所述空域参考块。
其中，当所述候选参考块与所述待处理图像块位于同一图像区域内，并且所述候选参考块基于所述仿射运动模型获得运动矢量时，则确定所述候选参考块可用。
在可能的实施例中，所述预设空域位置的候选参考块包括：位于所述待处理图像块正上方、正左方、右上方、左下方和左上方的相邻图像块；
所述参考块获取模块1001具体用于：按照正左方相邻图像块、正上方相邻图像块、右上方相邻图像块、左下方相邻图像块、左上方相邻图像块的顺序依次检查所述候选参考块的可用性，直到确定所述第一个可用的候选参考块。
在可能的实施例中，所述子块位置包括：所述子块内左上角像素点的位置；或者，所述子块的几何中心的位置，或者，所述子块内距离几何中心位置最近的一个像素点的位置。
在可能的实施例中，所述多个预设子块位置中的两个预设子块位置之间的距离为S，S为2的K次幂，K为非负整数。
在可能的实施例中，所述仿射运动模型为4参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)和第二预设位置(x4+M/2+P,y4+N/2)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，P为2的K次幂，K为非负整数，K小于U，U为所述空域参考块的宽度。
在可能的实施例中，所述仿射运动模型为4参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)和第三预设位置(x4+M/2,y4+N/2+Q)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，Q为2的R次幂，R为非负整数，Q小于V，V为所述空域参考块的高度。
在可能的实施例中，所述预设像素点位置包括所述待处理图像块内左上角像素点位置，所述第一计算模块1003具体用于，根据如下公式计算出所述待处理图像块预设像素点位置对应的运动矢量：
Figure PCTCN2019091364-appb-000065
Figure PCTCN2019091364-appb-000066
Figure PCTCN2019091364-appb-000067
其中，vx 0为所述待处理图像块内左上角像素点位置对应的运动矢量的水平分量，vy 0为所述待处理图像块内左上角像素点位置对应的运动矢量的竖直分量，vx 1为所述待处理图像块内右上角像素点位置对应的运动矢量的水平分量，vy 1为所述待处理图像块内右上角像素点位置对应的运动矢量的竖直分量，vx 2为所述待处理图像块内左下角像素点位置对应的运动矢量的水平分量，vy 2为所述待处理图像块内左下角像素点位置对应的运动矢量的竖直分量，vx 4为所述第一预设位置对应的运动矢量的水平分量，vy 4为所述第一预设位置对应的运动矢量的竖直分量，vx 5为所述第二预设位置对应的运动矢量的水平分量，vy 5为所述第二预设位置对应的运动矢量的竖直分量，x 0为所述待处理图像块内左上角像素点位置横坐标，y 0为所述待处理图像块内左上角像素点位置纵坐标，x 1为所述待处理图像块内右上角像素点位置横坐标，y 1为所述待处理图像块内右上角像素点位置纵坐标，x 2为所述待处理图像块内左下角像素点位置横坐标，y 2为所述待处理图像块内左下角像素点位置纵坐标。
在可能的实施例中，所述预设像素点位置包括所述待处理图像块内左上角像素点位置和所述待处理图像块内右上角像素点位置，所述第二计算模块1004具体用于，根据如下公式计算出所述待处理图像块中多个子块位置对应的运动矢量：
Figure PCTCN2019091364-appb-000068
其中，W为所述待处理图像块的宽度，vx为所述多个子块位置中位于(x,y)的一个对应的运动矢量的水平分量，vy为所述多个子块位置中位于(x,y)的一个对应的运动矢量的竖直分量。
在可能的实施例中，所述仿射运动模型为6参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)，第二预设位置(x4+M/2+P,y4+N/2)和第三预设位置(x4+M/2,y4+N/2+Q)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，P为2的K次幂，Q为2的R次幂，K和R为非负整数，P小于U，Q小于V,U为所述空域参考块的宽度,V为所述空域参考块的高度。
在可能的实施例中，所述预设像素点位置包括所述待处理图像块内左上角像素点位置，所述待处理图像块内右上角像素点位置和所述待处理图像块内左下角像素点位置，所述第 一计算模块1003具体用于，根据如下公式计算出所述待处理图像块预设像素点位置对应的运动矢量：
Figure PCTCN2019091364-appb-000069
Figure PCTCN2019091364-appb-000070
Figure PCTCN2019091364-appb-000071
其中，vx 0为所述待处理图像块内左上角像素点位置对应的运动矢量的水平分量，vy 0为所述待处理图像块内左上角像素点位置对应的运动矢量的竖直分量，vx 1为所述待处理图像块内右上角像素点位置对应的运动矢量的水平分量，vy 1为所述待处理图像块内右上角像素点位置对应的运动矢量的竖直分量，vx 2为所述待处理图像块内左下角像素点位置对应的运动矢量的水平分量，vy 2为所述待处理图像块内左下角像素点位置对应的运动矢量的竖直分量，vx 4为所述第一预设位置对应的运动矢量的水平分量，vy 4为所述第一预设位置对应的运动矢量的竖直分量，vx 5为所述第二预设位置对应的运动矢量的水平分量，vy 5为所述第二预设位置对应的运动矢量的竖直分量，vx 6为所述第三预设位置对应的运动矢量的水平分量，vy 6为所述第三预设位置对应的运动矢量的竖直分量，x 0为所述待处理图像块内左上角像素点位置横坐标，y 0为所述待处理图像块内左上角像素点位置纵坐标，x 1为所述待处理图像块内右上角像素点位置横坐标，y 1为所述待处理图像块内右上角像素点位置纵坐标，x 2为所述待处理图像块内左下角像素点位置横坐标，y 2为所述待处理图像块内左下角像素点位置纵坐标。
在可能的实施例中，所述第二计算模块1004具体用于，根据如下公式计算出所述待处理图像块中多个子块位置对应的运动矢量：
Figure PCTCN2019091364-appb-000072
其中，W为所述待处理图像块的宽度，H为所述待处理图像块的高度，vx为所述多个子块位置中位于(x,y)的一个对应的运动矢量的水平分量，vy为所述多个子块位置中位于(x,y)的一个对应的运动矢量的竖直分量。
在可能的实施例中，当所述待处理图像块的上边缘所在的直线和所述待处理图像块所在的编码树单元CTU的上边缘所在的直线重合，且所述空域参考块位于所述待处理图像块的正上方、左上方或右上方时，所述多个预设子块位置对应的子块中的至少两个子块与所述待处理图像块的上边缘邻接。
在可能的实施例中，当所述待处理图像块的左边缘所在的直线和所述待处理图像块所在的编码树单元CTU的左边缘所在的直线重合，且所述空域参考块位于所述待处理图像块的正左方、左上方或左下方时，所述多个预设子块位置对应的子块中的至少两个子块与所述待处理图像块的左边缘邻接。
在本发明上述实施例中，所述多个子块位置对应的运动矢量分别用于所述多个子块的运动矢量的预测。
需要说明的是，上述参考块获取模块1001、子块确定模块1002、第一计算模块1003和第二计算模块1004可应用于编码端或解码端的帧间预测过程。具体的，在编码端，这些模块可应用于前述编码器20的预测处理单元260中的帧间预测单元244；在解码端，这些模块可应用于前述解码器30的预测处理单元360中的帧间预测单元344。
还需要说明的是，参考块获取模块1001、子块确定模块1002、第一计算模块1003和第二计算模块1004的具体实现过程可参考图11、图12、图14实施例的详细描述，为了说明书的简洁，这里不再赘述。
在一个或一个以上实例中，所描述功能可以硬件、软件、固件或其任何组合来实施。如果在软件中实施，那么所述功能可作为一或多个指令或代码在计算机可读介质上存储或传输，并且由基于硬件的处理单元执行。计算机可读介质可以包含计算机可读存储介质，其对应于例如数据存储介质或通信介质的有形介质，通信介质例如根据通信协议包含有助于将计算机程序从一处传送到另一处的任何介质。以此方式，计算机可读介质通常可对应于非暂时性的有形计算机可读存储介质，或通信介质，例如，信号或载波。数据存储介质可以是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发明中描述的技术的指令、代码和/或数据结构的任何可用介质。计算机程序产品可包含计算机可读介质。
借助于实例而非限制，此类计算机可读存储介质可包括RAM、ROM、EEPROM、CD-ROM或其它光盘存储器、磁盘存储器或其它磁性存储设备、闪存，或可用以存储呈指令或数据结构形式的所需程序代码且可由计算机存取的任何其它介质。并且，任何连接可适当地称为计算机可读介质。举例来说，如果使用同轴电缆、光纤缆线、双绞线、数字订户线(digital subscriber line，DSL)或例如红外线、无线电及微波等无线技术从网站、服务器或其它远程源传输指令，则同轴电缆、光纤缆线、双绞线、DSL或例如红外线、无线电及微波等无线技术包含在介质的定义中。但是，应理解，所述计算机可读存储介质及数据存储介质并不包括连接、载波、信号或其它暂时性介质，而是实际上针对于非暂时性有形存储介质。如本文中所使用，磁盘和光盘包含压缩光盘(compact disc，CD)、激光光盘、光学光盘、数字多功能光盘(digital versatile disc，DVD)、软性磁盘及蓝光光盘，其中磁盘通常以磁性方式再现数据，而光盘用激光以光学方式再现数据。以上各项的组合也应包含于计算机可读介质的范围内。
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。

Claims (33)

  1. 一种基于仿射运动模型的运动矢量预测方法，其特征在于，包括：
    获取待处理图像块的一个空域参考块；
    确定所述空域参考块中多个预设子块位置；
    根据所述预设子块位置对应的运动矢量，插值计算出所述待处理图像块预设像素点位置对应的运动矢量；
    根据所述预设像素点位置对应的运动矢量，插值计算出所述待处理图像块中多个子块位置对应的运动矢量。
  2. 根据权利要求1所述的方法，其特征在于，所述获取待处理图像块的一个空域参考块，包括：
    按照预设顺序确定所述待处理图像块的一个或多个预设空域位置的候选参考块的可用性；
    获得在所述预设顺序中第一个可用的候选参考块作为所述空域参考块。
  3. 根据权利要求2所述的方法，其特征在于，当所述候选参考块与所述待处理图像块位于同一图像区域内，并且所述候选参考块基于所述仿射运动模型获得运动矢量时，确定所述候选参考块可用。
  4. 根据权利要求2或3所述的方法，其特征在于，所述预设空域位置的候选参考块包括：位于所述待处理图像块正上方、正左方、右上方、左下方和左上方的相邻图像块；
    对应的，所述按照预设顺序确定所述待处理图像块的一个或多个预设空域位置的候选参考块的可用性，包括：
    按照正左方相邻图像块、正上方相邻图像块、右上方相邻图像块、左下方相邻图像块、左上方相邻图像块的顺序依次检查所述候选参考块的可用性，直到确定所述第一个可用的候选参考块。
  5. 根据权利要求1至4任一项所述的方法，其特征在于，所述子块位置包括：
    所述子块内左上角像素点的位置；或者，
    所述子块的几何中心的位置，或者，
    所述子块内距离几何中心位置最近的一个像素点的位置。
  6. 根据权利要求1至5任一项所述的方法，其特征在于，所述多个预设子块位置中的两个预设子块位置之间的距离为S，S为2的K次幂，K为非负整数。
  7. 根据权利要求1至6任一项所述的方法，其特征在于，所述仿射运动模型为4参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)和第二预设位置 (x4+M/2+P,y4+N/2)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，P为2的K次幂，K为非负整数，K小于U，U为所述空域参考块的宽度。
  8. 根据权利要求1至6任一项所述的方法，其特征在于，所述仿射运动模型为4参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)和第三预设位置(x4+M/2,y4+N/2+Q)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，Q为2的R次幂，R为非负整数，Q小于V，V为所述空域参考块的高度。
  9. 根据权利要求7所述的方法，其特征在于，所述预设像素点位置包括所述待处理图像块内左上角像素点位置，所述待处理图像块内右上角像素点位置和所述待处理图像块内左下角像素点位置中的至少两个，所述根据所述预设子块位置对应的运动矢量，插值计算出所述待处理图像块预设像素点位置对应的运动矢量，包括根据如下公式计算出所述待处理图像块预设像素点位置对应的运动矢量：
    Figure PCTCN2019091364-appb-100001
    Figure PCTCN2019091364-appb-100002
    Figure PCTCN2019091364-appb-100003
    其中，vx 0为所述待处理图像块内左上角像素点位置对应的运动矢量的水平分量，vy 0为所述待处理图像块内左上角像素点位置对应的运动矢量的竖直分量，vx 1为所述待处理图像块内右上角像素点位置对应的运动矢量的水平分量，vy 1为所述待处理图像块内右上角像素点位置对应的运动矢量的竖直分量，vx 2为所述待处理图像块内左下角像素点位置对应的运动矢量的水平分量，vy 2为所述待处理图像块内左下角像素点位置对应的运动矢量的竖直分量，vx 4为所述第一预设位置对应的运动矢量的水平分量，vy 4为所述第一预设位置对应的运动矢量的竖直分量，vx 5为所述第二预设位置对应的运动矢量的水平分量，vy 5为所述第二预设位置对应的运动矢量的竖直分量，x 0为所述待处理图像块内左上角像素点位置横坐标，y 0为所述待处理图像块内左上角像素点位置纵坐标，x 1为所述待处理图像块内右上角像素点位置横坐标，y 1为所述待处理图像块内右上角像素点位置纵坐标，x 2为所述待处理图像块内左下角像素点位置横坐标，y 2为所述待处理图像块内左下角像素点位置纵坐标。
  10. 根据权利要求9所述的方法，其特征在于，所述预设像素点位置包括所述待处理 图像块内左上角像素点位置和所述待处理图像块内右上角像素点位置，所述根据所述预设像素点位置对应的运动矢量，插值计算出所述待处理图像块中多个子块位置对应的运动矢量，包括根据如下公式计算出所述待处理图像块中多个子块位置对应的运动矢量：
    Figure PCTCN2019091364-appb-100004
    其中，W为所述待处理图像块的宽度，vx为所述多个子块位置中位于(x,y)的一个对应的运动矢量的水平分量，vy为所述多个子块位置中位于(x,y)的一个对应的运动矢量的竖直分量。
  11. 根据权利要求1至6任一项所述的方法，其特征在于，所述仿射运动模型为6参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)，第二预设位置(x4+M/2+P,y4+N/2)和第三预设位置(x4+M/2,y4+N/2+Q)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，P为2的K次幂，Q为2的R次幂，K和R为非负整数，P小于U，Q小于V,U为所述空域参考块的宽度,V为所述空域参考块的高度。
  12. 根据权利要求11所述的方法，其特征在于，所述预设像素点位置包括所述待处理图像块内左上角像素点位置，所述待处理图像块内右上角像素点位置和所述待处理图像块内左下角像素点位置，所述根据所述预设子块位置对应的运动矢量，插值计算出所述待处理图像块预设像素点位置对应的运动矢量，包括根据如下公式计算出所述待处理图像块预设像素点位置对应的运动矢量：
    Figure PCTCN2019091364-appb-100005
    Figure PCTCN2019091364-appb-100006
    Figure PCTCN2019091364-appb-100007
    其中，vx 0为所述待处理图像块内左上角像素点位置对应的运动矢量的水平分量，vy 0为所述待处理图像块内左上角像素点位置对应的运动矢量的竖直分量，vx 1为所述待处理图像块内右上角像素点位置对应的运动矢量的水平分量，vy 1为所述待处理图像块内右上角像素点位置对应的运动矢量的竖直分量，vx 2为所述待处理图像块内左下角像素点位置对应的运动矢量的水平分量，vy 2为所述待处理图像块内左下角像素点位置对应的运动矢量的竖直分量，vx 4为所述第一预设位置对应的运动矢量的水平分量，vy 4为所述第一预设位置对应的运动 矢量的竖直分量，vx 5为所述第二预设位置对应的运动矢量的水平分量，vy 5为所述第二预设位置对应的运动矢量的竖直分量，vx 6为所述第三预设位置对应的运动矢量的水平分量，vy 6为所述第三预设位置对应的运动矢量的竖直分量，x 0为所述待处理图像块内左上角像素点位置横坐标，y 0为所述待处理图像块内左上角像素点位置纵坐标，x 1为所述待处理图像块内右上角像素点位置横坐标，y 1为所述待处理图像块内右上角像素点位置纵坐标，x 2为所述待处理图像块内左下角像素点位置横坐标，y 2为所述待处理图像块内左下角像素点位置纵坐标。
  13. 根据权利要求12所述的方法，其特征在于，所述根据所述预设像素点位置对应的运动矢量，插值计算出所述待处理图像块中多个子块位置对应的运动矢量，包括根据如下公式计算出所述待处理图像块中多个子块位置对应的运动矢量：
    Figure PCTCN2019091364-appb-100008
    其中，W为所述待处理图像块的宽度，H为所述待处理图像块的高度，vx为所述多个子块位置中位于(x,y)的一个对应的运动矢量的水平分量，vy为所述多个子块位置中位于(x,y)的一个对应的运动矢量的竖直分量。
  14. 根据权利要求1至13任一项所述的方法，其特征在于，当所述待处理图像块的上边缘所在的直线和所述待处理图像块所在的编码树单元CTU的上边缘所在的直线重合，且所述空域参考块位于所述待处理图像块的正上方、左上方或右上方时，所述多个预设子块位置对应的子块中的至少两个子块与所述待处理图像块的上边缘邻接。
  15. 根据权利要求1至13任一项所述的方法，其特征在于，当所述待处理图像块的左边缘所在的直线和所述待处理图像块所在的编码树单元CTU的左边缘所在的直线重合，且所述空域参考块位于所述待处理图像块的正左方、左上方或左下方时，所述多个预设子块位置对应的子块中的至少两个子块与所述待处理图像块的左边缘邻接。
  16. 根据权利要求1至15任一项所述的方法，其特征在于，所述多个子块位置对应的运动矢量分别用于所述多个子块的运动矢量的预测。
  17. 一种设备，其特征在于，包括：
    参考块获取模块，用于获取所述视频数据中的待处理图像块的一个空域参考块；
    子块确定模块，用于确定所述空域参考块中多个预设子块位置；
    第一计算模块，用于根据所述预设子块位置对应的运动矢量，插值计算出所述待处理图像块预设像素点位置对应的运动矢量；
    第二计算模块，用于根据所述预设像素点位置对应的运动矢量，插值计算出所述待处理图像块中多个子块位置对应的运动矢量。
  18. 根据权利要求17所述的设备，其特征在于，所述参考块获取模块具体用于：
    按照预设顺序确定所述待处理图像块的一个或多个预设空域位置的候选参考块的可用性；
    获得在所述预设顺序中第一个可用的候选参考块作为所述空域参考块。
  19. 根据权利要求18所述的设备，其特征在于，当所述候选参考块与所述待处理图像块位于同一图像区域内，并且所述候选参考块基于所述仿射运动模型获得运动矢量时，确定所述候选参考块可用。
  20. 根据权利要求18或19所述的设备，其特征在于，所述预设空域位置的候选参考块包括：位于所述待处理图像块正上方、正左方、右上方、左下方和左上方的相邻图像块；
    所述参考块获取模块具体用于：按照正左方相邻图像块、正上方相邻图像块、右上方相邻图像块、左下方相邻图像块、左上方相邻图像块的顺序依次检查所述候选参考块的可用性，直到确定所述第一个可用的候选参考块。
  21. 根据权利要求17至20任一项所述的设备，其特征在于，所述子块位置包括：
    所述子块内左上角像素点的位置；或者，
    所述子块的几何中心的位置，或者，
    所述子块内距离几何中心位置最近的一个像素点的位置。
  22. 根据权利要求17至21任一项所述的设备，其特征在于，所述多个预设子块位置中的两个预设子块位置之间的距离为S，S为2的K次幂，K为非负整数。
  23. 根据权利要求17至22任一项所述的设备，其特征在于，所述仿射运动模型为4参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)和第二预设位置(x4+M/2+P,y4+N/2)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，P为2的K次幂，K为非负整数，K小于U，U为所述空域参考块的宽度。
  24. 根据权利要求17至22任一项所述的设备，其特征在于，所述仿射运动模型为4参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)和第三预设位置(x4+M/2,y4+N/2+Q)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，Q为2的R次幂，R为非负整数，Q小于V，V为所述空域参考块的高度。
  25. 根据权利要求23所述的设备，其特征在于，所述预设像素点位置包括所述待处理图像块内左上角像素点位置，所述第一计算模块具体用于，根据如下公式计算出所述待处 理图像块预设像素点位置对应的运动矢量：
    Figure PCTCN2019091364-appb-100009
    Figure PCTCN2019091364-appb-100010
    Figure PCTCN2019091364-appb-100011
    其中，vx 0为所述待处理图像块内左上角像素点位置对应的运动矢量的水平分量，vy 0为所述待处理图像块内左上角像素点位置对应的运动矢量的竖直分量，vx 1为所述待处理图像块内右上角像素点位置对应的运动矢量的水平分量，vy 1为所述待处理图像块内右上角像素点位置对应的运动矢量的竖直分量，vx 2为所述待处理图像块内左下角像素点位置对应的运动矢量的水平分量，vy 2为所述待处理图像块内左下角像素点位置对应的运动矢量的竖直分量，vx 4为所述第一预设位置对应的运动矢量的水平分量，vy 4为所述第一预设位置对应的运动矢量的竖直分量，vx 5为所述第二预设位置对应的运动矢量的水平分量，vy 5为所述第二预设位置对应的运动矢量的竖直分量，x 0为所述待处理图像块内左上角像素点位置横坐标，y 0为所述待处理图像块内左上角像素点位置纵坐标，x 1为所述待处理图像块内右上角像素点位置横坐标，y 1为所述待处理图像块内右上角像素点位置纵坐标，x 2为所述待处理图像块内左下角像素点位置横坐标，y 2为所述待处理图像块内左下角像素点位置纵坐标。
  26. 根据权利要求25所述的设备，其特征在于，所述预设像素点位置包括所述待处理图像块内左上角像素点位置和所述待处理图像块内右上角像素点位置，所述第二计算模块具体用于，根据如下公式计算出所述待处理图像块中多个子块位置对应的运动矢量：
    Figure PCTCN2019091364-appb-100012
    其中，W为所述待处理图像块的宽度，vx为所述多个子块位置中位于(x,y)的一个对应的运动矢量的水平分量，vy为所述多个子块位置中位于(x,y)的一个对应的运动矢量的竖直分量。
  27. 根据权利要求17至22任一项所述的设备，其特征在于，所述仿射运动模型为6参数仿射运动模型，所述多个预设子块位置包括第一预设位置(x4+M/2,y4+N/2)，第二预设位置(x4+M/2+P,y4+N/2)和第三预设位置(x4+M/2,y4+N/2+Q)，其中，x4为所述空域参考块内左上角像素的位置横坐标，y4为所述空域参考块内左上角像素的位置纵坐标，M为子块宽度，N为子块高度，P为2的K次幂，Q为2的R次幂，K和R为非负整数，P小于U， Q小于V,U为所述空域参考块的宽度,V为所述空域参考块的高度。
  28. 根据权利要求27所述的设备，其特征在于，所述预设像素点位置包括所述待处理图像块内左上角像素点位置，所述待处理图像块内右上角像素点位置和所述待处理图像块内左下角像素点位置，所述第一计算模块具体用于，根据如下公式计算出所述待处理图像块预设像素点位置对应的运动矢量：
    Figure PCTCN2019091364-appb-100013
    Figure PCTCN2019091364-appb-100014
    Figure PCTCN2019091364-appb-100015
    其中，vx 0为所述待处理图像块内左上角像素点位置对应的运动矢量的水平分量，vy 0为所述待处理图像块内左上角像素点位置对应的运动矢量的竖直分量，vx 1为所述待处理图像块内右上角像素点位置对应的运动矢量的水平分量，vy 1为所述待处理图像块内右上角像素点位置对应的运动矢量的竖直分量，vx 2为所述待处理图像块内左下角像素点位置对应的运动矢量的水平分量，vy 2为所述待处理图像块内左下角像素点位置对应的运动矢量的竖直分量，vx 4为所述第一预设位置对应的运动矢量的水平分量，vy 4为所述第一预设位置对应的运动矢量的竖直分量，vx 5为所述第二预设位置对应的运动矢量的水平分量，vy 5为所述第二预设位置对应的运动矢量的竖直分量，vx 6为所述第三预设位置对应的运动矢量的水平分量，vy 6为所述第三预设位置对应的运动矢量的竖直分量，x 0为所述待处理图像块内左上角像素点位置横坐标，y 0为所述待处理图像块内左上角像素点位置纵坐标，x 1为所述待处理图像块内右上角像素点位置横坐标，y 1为所述待处理图像块内右上角像素点位置纵坐标，x 2为所述待处理图像块内左下角像素点位置横坐标，y 2为所述待处理图像块内左下角像素点位置纵坐标。
  29. 根据权利要求28所述的设备，其特征在于，所述第二计算模块具体用于，根据如下公式计算出所述待处理图像块中多个子块位置对应的运动矢量：
    Figure PCTCN2019091364-appb-100016
    其中，W为所述待处理图像块的宽度，H为所述待处理图像块的高度，vx为所述多个子块位置中位于(x,y)的一个对应的运动矢量的水平分量，vy为所述多个子块位置中位于(x,y)的 一个对应的运动矢量的竖直分量。
  30. 根据权利要求17至29任一项所述的设备，其特征在于，当所述待处理图像块的上边缘所在的直线和所述待处理图像块所在的编码树单元CTU的上边缘所在的直线重合，且所述空域参考块位于所述待处理图像块的正上方、左上方或右上方时，所述多个预设子块位置对应的子块中的至少两个子块与所述待处理图像块的上边缘邻接。
  31. 根据权利要求17至29任一项所述的设备，其特征在于，当所述待处理图像块的左边缘所在的直线和所述待处理图像块所在的编码树单元CTU的左边缘所在的直线重合，且所述空域参考块位于所述待处理图像块的正左方、左上方或左下方时，所述多个预设子块位置对应的子块中的至少两个子块与所述待处理图像块的左边缘邻接。
  32. 根据权利要求17至31任一项所述的设备，其特征在于，所述多个子块位置对应的运动矢量分别用于所述多个子块的运动矢量的预测。
  33. 一种视频编解码设备，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权利要求1-16任一项所描述的方法。
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