WO2020135368A1 - 一种帧间预测的方法和装置 - Google Patents

一种帧间预测的方法和装置 Download PDF

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Publication number
WO2020135368A1
WO2020135368A1 PCT/CN2019/127669 CN2019127669W WO2020135368A1 WO 2020135368 A1 WO2020135368 A1 WO 2020135368A1 CN 2019127669 W CN2019127669 W CN 2019127669W WO 2020135368 A1 WO2020135368 A1 WO 2020135368A1
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motion vector
accuracy
motion
processed
control point
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PCT/CN2019/127669
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English (en)
French (fr)
Inventor
陈焕浜
杨海涛
张恋
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华为技术有限公司
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Priority claimed from CN201910108004.4A external-priority patent/CN111355961B/zh
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to KR1020217023306A priority Critical patent/KR20210103561A/ko
Priority to EP19902475.3A priority patent/EP3896970A4/en
Publication of WO2020135368A1 publication Critical patent/WO2020135368A1/zh
Priority to US17/357,555 priority patent/US11706444B2/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

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  • Embodiments of the present application relate to the field of video encoding and decoding, and in particular, to an inter-frame prediction method and device.
  • Video signals have become the most important way for people to obtain information in their daily lives due to their intuitive and efficient advantages. Due to the large amount of data contained in the video signal, a large amount of transmission bandwidth and storage space are required. In order to effectively transmit and store video signals, it is necessary to compress and encode the video signals, and video compression technology is increasingly becoming an indispensable key technology in the video application field. In the process of encoding and decoding, in order to save storage space, the motion information is usually stored with lower precision. However, if the motion information is still encoded or decoded with lower precision, the accuracy of inter prediction is lower.
  • Embodiments of the present application provide an inter prediction method and device, which can effectively improve the accuracy of inter prediction.
  • an embodiment of the present application provides an inter prediction method, including: determining that the prediction mode of an image block to be processed is a prediction mode based on an affine motion model; and obtaining the motion of the control point of the image block to be processed Vector; based on the motion vector of the control point, derive the motion vector of each motion compensation unit in the image block to be processed; based on the motion vector of each motion compensation unit, perform motion compensation separately to obtain the Processing the prediction block of the image block; processing the motion vector of the motion compensation unit to meet the preset motion vector accuracy and/or motion vector bit depth; based on the prediction block and the processed motion vector, obtaining the Process reconstruction blocks of image blocks.
  • the processing of the motion vector of the motion compensation unit to meet a preset motion vector accuracy and/or motion vector bit depth includes: comparing the motion vector accuracy of the motion compensation unit and/ Or the motion vector bit depth, and the preset motion vector accuracy and/or motion vector bit depth; when the motion vector of the motion compensation unit does not satisfy the preset motion vector accuracy and/or motion vector bit depth, the The motion vector accuracy and/or motion vector bit depth of the motion compensation unit is converted into the preset motion vector accuracy and/or motion vector bit depth.
  • converting the motion vector accuracy and/or motion vector bit depth of the motion compensation unit into the preset motion vector accuracy and/or motion vector bit depth includes:
  • the accuracy and bit depth of the motion vector of the storage unit are 1/4, 16bit, and the accuracy and bit depth of the motion vector of the motion compensation unit are 1/16, 18bit, then the accuracy and bit depth of the motion information storage of the final motion compensation unit is 1/4, 16bit.
  • the 1/4-precision motion vector can be obtained by directly deriving from the formula (9) in the specification for storage; or the step can be directly derived from the motion vector of the control point according to the motion vector of the control point.
  • the motion vector with 1/16 precision obtained from the motion vector is quantized to obtain the motion vector with 1/4 precision.
  • the quantization method is as the round function in the following, where mvShift is set to 2.
  • the method further includes: when the motion vector of the motion compensation unit satisfies a preset motion vector accuracy and/or motion vector bit depth, the conversion is not performed.
  • the obtaining the reconstructed block of the image block to be processed based on the prediction block and the processed motion vector includes: converting the prediction block and the image block to be processed The residual blocks of are added to obtain the reconstructed block of the image block to be processed; or, the prediction block is updated according to the processed motion vector, and the updated prediction block and the to-be-processed Adding the residual blocks of the image blocks to obtain the reconstructed block of the image block to be processed; or, adding the prediction block and the residual blocks of the image block to be processed to obtain the reconstruction of the image block to be processed Block, filtering the reconstructed block based on the processed motion vector; or, adding the prediction block and the residual block of the image block to be processed to obtain the reconstruction of the image block to be processed Block, using the processed motion vector and the reconstructed block as prediction information of the subsequent image block to be processed.
  • an embodiment of the present application provides an inter prediction method, including: determining that the prediction mode of an image block to be processed is a prediction mode based on an affine motion model; and obtaining the motion of the control point of the image block to be processed Vector; process the motion vector of the control point to meet the preset motion vector accuracy and/or motion vector bit depth; according to the processed motion vector, derive the motion of each motion compensation unit in the image block to be processed Vector; based on the motion vector of each motion compensation unit, separately perform motion compensation to obtain the prediction block of the image block to be processed.
  • the processing of the motion vector of the control point to meet a preset motion vector accuracy and/or motion vector bit depth includes: comparing the motion vector accuracy and/or motion of the control point Vector bit depth, and the preset motion vector accuracy and/or motion vector bit depth; when the motion vector of the control point does not satisfy the preset motion vector accuracy and/or motion vector bit depth, the control The precision of the motion vector of the point and/or the bit depth of the motion vector are converted into the preset motion vector precision and/or the bit depth of the motion vector.
  • the conversion of the motion vector accuracy and/or motion vector bit depth of the control point into the preset motion vector accuracy and/or motion vector bit depth includes:
  • CPMV is obtained by the inherited motion vector prediction method
  • the accuracy and bit depth of CPMV can be obtained from the adjacent affine unit of the current block, where the motion vector accuracy and bit depth of the adjacent block are obtained by reading the storage unit
  • the motion information is obtained, which is 1/4 precision, 16bit.
  • the motion vector with 1/16 precision can be derived from the formulas (6) and (7) in the specification.
  • 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 accuracy and storage of the CPMVP are the same as those of the neighboring blocks, that is, 1/4 precision and 16 bits. Then shift left by 2 bits to get 1/4 precision, 18bit CPMV.
  • the method further includes: when the motion vector of the control point satisfies a preset motion vector accuracy and/or motion vector bit depth, the conversion is not performed.
  • an embodiment of the present application provides an apparatus for inter prediction, including: a determination module for determining that the prediction mode of an image block to be processed is a prediction mode based on an affine motion model; and an acquisition module for obtaining The motion vector of the control point of the image block to be processed; the calculation module for deriving the motion vector of each motion compensation unit in the image block to be processed according to the motion vector of the control point; the compensation module for The motion vector of each motion compensation unit is separately subjected to motion compensation to obtain the prediction block of the image block to be processed; a processing module is used to process the motion vector of the motion compensation unit to meet the preset motion vector accuracy and /Or the bit depth of the motion vector; the reconstruction module, used to obtain the reconstructed block of the image block to be processed based on the prediction block and the processed motion vector.
  • the processing module is specifically configured to compare the motion vector accuracy and/or motion vector bit depth of the motion compensation unit with the preset motion vector accuracy and/or motion vector bit Depth; when the motion vector of the motion compensation unit does not meet the preset motion vector accuracy and/or motion vector bit depth, convert the motion vector accuracy and/or motion vector bit depth of the motion compensation unit to the pre- Set the motion vector accuracy and/or motion vector bit depth.
  • the processing module is further configured to not perform the conversion when the motion vector of the motion compensation unit satisfies the preset motion vector accuracy and/or motion vector bit depth.
  • the reconstruction module is specifically configured to: add the prediction block and the residual block of the image block to be processed to obtain a reconstruction block of the image block to be processed; or, according to The processed motion vector, updating the prediction block, adding the updated prediction block and the residual block of the image block to be processed, to obtain a reconstructed block of the image block to be processed; or , Adding the prediction block and the residual block of the to-be-processed image block to obtain a reconstructed block of the to-be-processed image block, and filtering the reconstructed block based on the processed motion vector; or , Adding the prediction block and the residual block of the to-be-processed image block to obtain a reconstructed block of the to-be-processed image block, and using the processed motion vector and the reconstructed block as subsequent to-be-processed image blocks Forecast information.
  • an embodiment of the present application provides an apparatus for inter prediction, including: a determination module for determining that the prediction mode of an image block to be processed is a prediction mode based on an affine motion model; and an acquisition module for obtaining The motion vector of the control point of the image block to be processed; the processing module for processing the motion vector of the control point to meet the preset motion vector accuracy and/or motion vector bit depth; the calculation module for processing according to the processing After the motion vector, derive the motion vector of each motion compensation unit in the image block to be processed; a compensation module is used to perform motion compensation based on the motion vector of each motion compensation unit to obtain the to-be-processed The prediction block of the image block.
  • the processing module is specifically configured to: compare the motion vector accuracy and/or motion vector bit depth of the control point with the preset motion vector accuracy and/or motion vector bit depth ; When the motion vector of the control point does not satisfy the preset motion vector accuracy and/or motion vector bit depth, convert the motion vector accuracy and/or motion vector bit depth of the control point into the preset motion Vector accuracy and/or motion vector bit depth.
  • the processing module is further configured to not perform the conversion when the motion vector of the control point satisfies the preset motion vector accuracy and/or motion vector bit depth.
  • an embodiment of the present application provides a video codec device, including: a non-volatile memory and a processor coupled to each other, and the processor calls program codes stored in the memory to perform any of the above aspects The method.
  • this application can improve the accuracy of the motion vector of the control point and the bit depth to perform motion compensation, which can effectively improve the use of affine motion models.
  • the accuracy of the inter prediction of the coding block can improve the accuracy of the inter prediction of the coding block.
  • the name of the inter prediction device does not limit the device itself, and in actual implementation, these devices may appear under other names. As long as the functions of each device are similar to the embodiments of the present application, they fall within the scope of the claims of the present application and their equivalent technologies.
  • an embodiment of the present application provides an inter-frame prediction method, including: after determining that the prediction mode of an image block to be processed is an advanced motion vector (Advanced Motion Vector (AMVP) mode based on an affine motion model, Obtain the motion vector of the control point of the image block to be processed, and then, based on the motion vector of the control point, derive the motion vector of each motion compensation unit in the image block to be processed; based on the motion vector of each motion compensation unit, obtain the image to be processed The reconstruction block of the block.
  • the motion vector of the control point satisfies the preset first motion vector accuracy and/or the first motion vector bit depth.
  • the accuracy change process in the affine AMVP mode proposed by the embodiment of the present application can effectively improve the inter-frame of the coding block using the affine motion model by improving the accuracy and bit depth of the motion vector of the control point and performing motion compensation Forecast accuracy.
  • obtaining the motion vector of the control point of the image block to be processed includes: obtaining the difference between the control point motion vector prediction values (control point motion vectors differences) (CPMVD) And control point motion vector prediction value (control point motion vectors predictor, CPMVP); when the accuracy of CPMVD is not equal to the first motion vector accuracy, according to CPMVD and the first offset value, the motion vector of the control point of the image block to be processed is obtained Or, when the accuracy of CPMVP is not equal to the accuracy of the first motion vector, the motion vector of the control point of the image block to be processed is obtained according to the CPMVP and the second offset value.
  • CPMVD control point motion vectors differences
  • CPMVP control point motion vectors predictor
  • the motion vector of the control point of the image block to be processed is obtained by the following formula:
  • the first offset value is equal to 0; when the first motion vector accuracy is 1/16 pixel accuracy and CPMVD accuracy When the precision is 1/4 pixel, the first offset value is equal to 2; when the first motion vector precision is 1/16 pixel precision and the precision of CPMVD is integer pixel precision, the first offset value is equal to 4; when the first motion When the vector accuracy is 1/16 pixel accuracy and the CPMVP accuracy is 1/16 pixel accuracy, the second offset value is equal to 0; when the first motion vector accuracy is 1/16 pixel accuracy and the CPMVP accuracy is 1/4 pixel accuracy When the second offset value is equal to 2; when the first motion vector accuracy is 1/16 pixel accuracy and the CPMVP accuracy is integer pixel accuracy, the second offset value is equal to 4.
  • the motion vector of the control point when the bit depth of the motion vector of the control point is greater than the bit depth of the first motion vector, the motion vector of the control point is clamped to make the motion vector of the control point The bit depth of is equal to the bit depth of the first motion vector.
  • the motion vector of the control point is clamped so that the bit depth of the motion vector of the control point is equal to the bit depth of the first motion vector.
  • the method further includes: processing the motion vector accuracy of the motion compensation unit to meet a preset second motion vector accuracy, and/or, processing motion compensation The motion vector bit depth of the unit satisfies the preset second motion vector accuracy bit depth; the processed motion vector of the motion compensation unit is stored.
  • the motion vector of the processed motion compensation unit is obtained by the following formula:
  • MCUMV' (MCUMV>>mvrShift3), where MCUMV' represents the motion vector of the motion compensation unit after processing, MCUMV represents the motion vector of the motion compensation unit before processing, and mvrShift3 represents the third offset value.
  • the third offset value is equal to 2; when the second motion vector accuracy is 1/4 pixel accuracy and MCUMV accuracy When it is 1/4 pixel precision, the third offset value is equal to 0; when the second motion vector accuracy is 1/4 pixel precision and the MCUMV accuracy is 1/32 pixel precision, the third offset value is equal to 3.
  • the method further includes: clamping the bit depth of the motion vector of the processed motion compensation unit to make the bit depth of the motion vector of the processed motion compensation unit equal to The second motion vector bit depth.
  • the method further includes: when the bit depth of the motion vector of the processed motion compensation unit is greater than the bit depth of the second motion vector, the motion of the processed motion compensation unit The vector is clamped so that the bit depth of the motion vector of the processed motion compensation unit is equal to the bit depth of the second motion vector.
  • obtaining the reconstruction block of the image block to be processed based on the motion vector of each motion compensation unit includes: based on the motion vector of each motion compensation unit , Separately perform motion compensation to obtain the prediction block of the image block to be processed; based on the prediction block and the motion vector of each motion compensation unit, obtain the reconstruction block of the image block to be processed.
  • an embodiment of the present application provides an inter-frame prediction method, including: after determining that the prediction mode of the image block to be processed is a fusion prediction mode based on an affine motion model, obtaining the image block to be processed The motion vector of the control point; the motion vector of the control point is adjusted to meet the preset first motion vector accuracy and/or the first motion vector bit depth; according to the adjusted motion vector of the control point, each of the image blocks to be processed is derived The motion vector of the motion compensation unit; based on the motion vector of each motion compensation unit, the reconstruction block of the image block to be processed is acquired.
  • Embodiment 1 of the present application proposes an accuracy change process in the affine AMVP mode. By improving the accuracy and bit depth of the motion vector of the control point and performing motion compensation, the frame of the coding block using the affine motion model can be effectively improved Prediction accuracy.
  • adjusting the motion vector of the control point includes: when the accuracy of the motion vector of the control point is not equal to the accuracy of the first motion vector, according to the motion vector of the control point and the first The offset value is used to obtain the motion vector of the adjusted control point.
  • the motion vector of the adjusted control point is obtained by the following formula:
  • CPMV' CPMV ⁇ mvrShift1
  • CPMV represents the motion vector of the control point
  • CPMV' represents the motion vector of the adjusted control point
  • mvrShift1 represents the first offset value
  • the first offset value is equal to 0; when the first motion vector accuracy is 1/16 pixel accuracy When the precision of the motion vector of the control point is 1/4 pixel precision, the first offset value is equal to 2; when the precision of the first motion vector is 1/16 pixel precision and the precision of the motion vector of the control point is whole pixel precision, The first offset value is equal to 4.
  • the method further includes: when the bit depth of the adjusted control point's motion vector is greater than the first motion vector's bit depth, performing the adjusted control point's motion vector Clamp so that the bit depth of the adjusted control point motion vector is equal to the first motion vector bit depth.
  • the method further includes: clamping the motion vector of the adjusted control point so that the bit depth of the motion vector of the adjusted control point is equal to the first motion vector bit depth.
  • the prediction mode of the processed adjacent image blocks of the image block to be processed is a prediction mode based on an affine motion model, when the motion vector of the control point of the image block to be processed
  • the motion vectors of the adjusted control points are obtained by the following formula:
  • K1 mvScaleHor+dHorX*(x0–x4–M/2)+dHorY*(y0–y4–N/2),
  • K6 mvScaleVer+dVerX*(x2–x4–M/2)+dVerY*(y2–y4–N/2),
  • Log2() represents the function of taking the logarithm of 2
  • ⁇ represents left shift
  • >> represents right shift
  • P is the width of the processed adjacent image block
  • Q is the height of the processed adjacent image block
  • (vx0,vy0), (vx1,vy1) and (vx2,vy2) represent the horizontal and vertical components of the motion vectors of the three control points of the image block to be processed, that is, (vx0,vy0) is the image to be processed
  • the horizontal and vertical components of the motion vector of the first control point of the block, (vx1,vy1) are the horizontal and vertical components of the motion vector of the second control point of the image block to be processed, (vx2,vy2) Are the horizontal and vertical components of the motion vector of the third control point of the image block to be processed,
  • (vx4, vy4), (vx5, vy5), and (vx6, vy6) represent the horizontal and vertical components of the motion vectors of the three control points of the adjacent image blocks, that is, (vx4, vy4) is already Process the horizontal and vertical components of the motion vector of the first control point of the adjacent image block, (vx5,vy5) is the horizontal and vertical components of the motion vector of the second control point of the processed adjacent image block , (Vx6,vy6) is the horizontal and vertical components of the motion vector of the third control point of the neighboring image block,
  • mvShift is determined based on the motion vector accuracy of the control points of the neighboring image blocks that have been processed.
  • adjacent image blocks may refer to spatially adjacent affine coding blocks or temporally adjacent affine coding blocks.
  • the accuracy of the CPMV stored in the adjacent affine block is 1/4 pixel accuracy
  • the accuracy of the CPMV of the image block to be processed is 1/16 pixel accuracy.
  • the accuracy of the CPMV stored in the adjacent affine block is 1/4 pixel accuracy
  • mvShift can be set to 6
  • the accuracy of the CPMV of the image block to be processed is 1/32 pixel accuracy.
  • the accuracy of the CPMV stored in the adjacent affine block is 1/4 pixel accuracy
  • mvShift can be set to 7 and the accuracy of the CPMV of the image block to be processed is 1/4 pixel accuracy.
  • the accuracy of the CPMV of the adjacent affine block may refer to the accuracy of the stored motion vector of the storage unit.
  • the method further includes: processing the motion vector accuracy of the motion compensation unit to meet a preset second motion vector accuracy, and/or, processing motion compensation The motion vector bit depth of the unit satisfies the preset second motion vector accuracy bit depth; the processed motion vector of the motion compensation unit is stored.
  • the motion vector of the processed motion compensation unit is obtained by the following formula:
  • MCUMV' (MCUMV>>mvrShift2), where MCUMV' represents the motion vector of the motion compensation unit after processing, MCUMV represents the motion vector of the motion compensation unit before processing, and mvrShift2 represents the second offset value.
  • the second offset value is equal to 2; when the second motion vector accuracy is 1/4 pixel accuracy and MCUMV accuracy When it is 1/4 pixel accuracy, the second offset value is equal to 0; when the second motion vector accuracy is 1/4 pixel precision and the MCUMV accuracy is 1/32 pixel precision, the second offset value is equal to 3.
  • the method further includes: clamping the bit depth of the motion vector of the processed motion compensation unit to make the bit depth of the motion vector of the processed motion compensation unit equal to The second motion vector bit depth.
  • the method further includes: when the bit depth of the motion vector of the processed motion compensation unit is greater than the bit depth of the second motion vector, the motion of the processed motion compensation unit The vector is clamped so that the bit depth of the motion vector of the processed motion compensation unit is equal to the bit depth of the second motion vector.
  • acquiring the reconstruction block of the image block to be processed based on the motion vector of each motion compensation unit includes: based on the motion vector of each motion compensation unit , Separately perform motion compensation to obtain the prediction block of the image block to be processed; based on the prediction block and the motion vector of each motion compensation unit, obtain the reconstruction block of the image block to be processed.
  • an embodiment of the present application provides an apparatus for inter prediction, including: a determination module for determining that the prediction mode of an image block to be processed is an AMVP mode based on an affine motion model; and an acquisition module for obtaining Process the motion vector of the control point of the image block, the motion vector of the control point meets the preset first motion vector accuracy and/or the first motion vector bit depth; the calculation module is used to derive the image to be processed according to the motion vector of the control point The motion vector of each motion compensation unit in the block; the reconstruction module is used to obtain a reconstruction block of the image block to be processed based on the motion vector of each motion compensation unit.
  • the acquisition module is specifically used to: acquire CPMVD and CPMVP; when the accuracy of CPMVD is not equal to the accuracy of the first motion vector, according to CPMVD and the first offset value, obtain the pending Process the motion vector of the control point of the image block; or, when the accuracy of the CPMVP is not equal to the first motion vector accuracy, obtain the motion vector of the control point of the image block to be processed according to the CPMVP and the second offset value.
  • the motion vector of the control point of the image block to be processed is obtained by the following formula:
  • CPMV CPMVD'+CPMVP'.
  • CPMVD' CPMVD ⁇ mvrShift1.
  • CPMVP CPMVP ⁇ mvrShift2.
  • CPMVP' CPMVP.
  • CPMV represents the motion vector of the control point
  • mvrShift1 represents the first offset value
  • mvrShift2 represents the second offset value.
  • the first offset value is equal to 0; when the first motion vector accuracy is 1/16 pixel accuracy and CPMVD accuracy When the precision is 1/4 pixel, the first offset value is equal to 2; when the first motion vector precision is 1/16 pixel precision and the precision of CPMVD is integer pixel precision, the first offset value is equal to 4; when the first motion When the vector accuracy is 1/16 pixel accuracy and the CPMVP accuracy is 1/16 pixel accuracy, the second offset value is equal to 0; when the first motion vector accuracy is 1/16 pixel accuracy and the CPMVP accuracy is 1/4 pixel accuracy When the second offset value is equal to 2; when the first motion vector accuracy is 1/16 pixel accuracy and the CPMVP accuracy is integer pixel accuracy, the second offset value is equal to 4.
  • the acquisition module is further configured to: when the bit depth of the motion vector of the control point is greater than the bit depth of the first motion vector, clamp the motion vector of the control point to Make the bit depth of the motion vector of the control point equal to the bit depth of the first motion vector.
  • the acquisition module is further configured to: clamp the motion vector of the control point so that the bit depth of the motion vector of the control point is equal to the bit depth of the first motion vector.
  • the acquisition module is further configured to: process the motion vector accuracy of the motion compensation unit to meet the preset second motion vector accuracy, and/or, process The motion vector bit depth of the motion compensation unit satisfies the preset second motion vector precision bit depth; the device further includes a storage module: a storage module for storing the motion vector of the processed motion compensation unit.
  • the motion vector of the processed motion compensation unit is obtained by the following formula:
  • MCUMV' (MCUMV>>mvrShift3), where MCUMV' represents the motion vector of the motion compensation unit after processing, MCUMV represents the motion vector of the motion compensation unit before processing, and mvrShift3 represents the third offset value.
  • the third offset value is equal to 2; when the second motion vector accuracy is 1/4 pixel accuracy and MCUMV accuracy When it is 1/4 pixel precision, the third offset value is equal to 0; when the second motion vector accuracy is 1/4 pixel precision and the MCUMV accuracy is 1/32 pixel precision, the third offset value is equal to 3.
  • the acquisition module is further configured to: clamp the bit depth of the motion vector of the processed motion compensation unit to make the motion vector of the processed motion compensation unit The bit depth is equal to the second motion vector bit depth.
  • the acquisition module is further configured to: when the bit depth of the motion vector of the processed motion compensation unit is greater than the bit depth of the second motion vector, compensate the processed motion The motion vector of the unit is clamped so that the bit depth of the motion vector of the processed motion compensation unit is equal to the bit depth of the second motion vector.
  • the reconstruction module is specifically configured to: perform motion compensation based on the motion vector of each motion compensation unit to obtain the prediction block of the image block to be processed ; Based on the prediction block and the motion vector of each motion compensation unit, obtain a reconstructed block of the image block to be processed.
  • an embodiment of the present application provides an apparatus for inter prediction, including: a determination module for determining that the prediction mode of an image block to be processed is a fusion Merge prediction mode based on an affine motion model; and an acquisition module for Obtain the motion vector of the control point of the image block to be processed; the adjustment module, used to adjust the motion vector of the control point to meet the preset first motion vector accuracy and/or the first motion vector bit depth; the calculation module, used to adjust After the motion vectors of the control points, the motion vector of each motion compensation unit in the image block to be processed is derived; the reconstruction module is used to obtain the reconstruction block of the image block to be processed based on the motion vector of each motion compensation unit.
  • the adjustment module is specifically configured to: when the accuracy of the motion vector of the control point is not equal to the accuracy of the first motion vector, according to the motion vector of the control point and the first offset value To obtain the motion vector of the adjusted control point.
  • the motion vector of the adjusted control point is obtained by the following formula:
  • CPMV' CPMV ⁇ mvrShift1
  • CPMV represents the motion vector of the control point
  • CPMV' represents the motion vector of the adjusted control point
  • mvrShift1 represents the first offset value
  • the first offset value is equal to 0; when the first motion vector accuracy is 1/16 pixel accuracy When the precision of the motion vector of the control point is 1/4 pixel precision, the first offset value is equal to 2; when the precision of the first motion vector is 1/16 pixel precision and the precision of the motion vector of the control point is whole pixel precision, The first offset value is equal to 4.
  • the adjustment module is further configured to: when the bit depth of the adjusted control point motion vector is greater than the first motion vector bit depth, the adjustment control point The motion vector is clamped so that the bit depth of the adjusted control point motion vector is equal to the first motion vector bit depth.
  • the adjustment module is further used to: clamp the motion vector of the adjusted control point so that the bit depth of the motion vector of the adjusted control point is equal to the first Motion vector bit depth.
  • the prediction mode of the processed adjacent image blocks of the image block to be processed is a prediction mode based on the affine motion model, when the motion vector of the control point of the image block to be processed
  • the motion vectors of the adjusted control points are obtained by the following formula:
  • K1 mvScaleHor+dHorX*(x0–x4–M/2)+dHorY*(y0–y4–N/2),
  • K6 mvScaleVer+dVerX*(x2–x4–M/2)+dVerY*(y2–y4–N/2),
  • Log2() represents the function of taking the logarithm of 2
  • ⁇ represents left shift
  • >> represents right shift
  • P is the width of the processed adjacent image block
  • Q is the height of the processed adjacent image block
  • (vx0,vy0), (vx1,vy1) and (vx2,vy2) represent the horizontal and vertical components of the motion vectors of the three control points of the image block to be processed, that is, (vx0,vy0) is the image to be processed
  • the horizontal and vertical components of the motion vector of the first control point of the block, (vx1,vy1) are the horizontal and vertical components of the motion vector of the second control point of the image block to be processed, (vx2,vy2) Are the horizontal and vertical components of the motion vector of the third control point of the image block to be processed,
  • (vx4, vy4), (vx5, vy5), and (vx6, vy6) represent the horizontal and vertical components of the motion vectors of the three control points of the adjacent image blocks, that is, (vx4, vy4) is already Process the horizontal and vertical components of the motion vector of the first control point of the adjacent image block, (vx5,vy5) is the horizontal and vertical components of the motion vector of the second control point of the processed adjacent image block , (Vx6, vy6) is the horizontal and vertical components of the motion vector of the third control point of the adjacent image block,
  • mvShift is determined based on the motion vector accuracy of the control points of the neighboring image blocks that have been processed.
  • adjacent image blocks may refer to spatially adjacent affine coding blocks or temporally adjacent affine coding blocks.
  • the accuracy of the CPMV stored in the adjacent affine block is 1/4 pixel accuracy
  • the accuracy of the CPMV of the image block to be processed is 1/16 pixel accuracy.
  • the accuracy of the CPMV stored in the adjacent affine block is 1/4 pixel accuracy
  • mvShift can be set to 6
  • the accuracy of the CPMV of the image block to be processed is 1/32 pixel accuracy.
  • the accuracy of the CPMV stored in the adjacent affine block is 1/4 pixel accuracy
  • mvShift can be set to 7 and the accuracy of the CPMV of the image block to be processed is 1/4 pixel accuracy.
  • the accuracy of the CPMV of the adjacent affine block may refer to the accuracy of the stored motion vector of the storage unit.
  • the adjustment module is further configured to: process the motion vector accuracy of the motion compensation unit to meet the preset second motion vector accuracy, and/or, process The motion vector bit depth of the motion compensation unit satisfies the preset second motion vector precision bit depth; the device further includes a storage module: a storage module for storing the motion vector of the processed motion compensation unit.
  • the motion vector of the processed motion compensation unit is obtained by the following formula:
  • MCUMV' (MCUMV>>mvrShift2), where MCUMV' represents the motion vector of the motion compensation unit after processing, MCUMV represents the motion vector of the motion compensation unit before processing, and mvrShift2 represents the second offset value.
  • the second offset value is equal to 2; when the second motion vector accuracy is 1/4 pixel accuracy and MCUMV accuracy When it is 1/4 pixel accuracy, the second offset value is equal to 0; when the second motion vector accuracy is 1/4 pixel precision and the MCUMV accuracy is 1/32 pixel precision, the second offset value is equal to 3.
  • the adjustment module is further used to: clamp the bit depth of the motion vector of the processed motion compensation unit to make the motion vector of the processed motion compensation unit
  • the bit depth is equal to the second motion vector bit depth.
  • the adjustment module is further configured to: when the bit depth of the motion vector of the processed motion compensation unit is greater than the bit depth of the second motion vector, compensate the processed motion The motion vector of the unit is clamped so that the bit depth of the motion vector of the processed motion compensation unit is equal to the bit depth of the second motion vector.
  • the reconstruction module is specifically configured to: perform motion compensation based on the motion vector of each motion compensation unit to obtain the prediction block of the image block to be processed ; Based on the prediction block and the motion vector of each motion compensation unit, obtain a reconstructed block of the image block to be processed.
  • an apparatus for inter prediction including: a processor and a memory coupled to the processor; the processor is configured to perform the first aspect, the second aspect, the sixth aspect, or the seventh aspect In any aspect, the method for inter prediction described in any feasible implementation manner.
  • a computer-readable storage medium in which instructions are stored in the computer-readable storage medium, and when the instructions run on a computer, the computer is caused to perform the first aspect and the second aspect ,
  • a computer program product containing instructions that, when the instructions run on a computer, cause the computer to perform any one of the first, second, sixth or seventh aspects A feasible method for implementing inter prediction.
  • a video image encoder including any of the feasible implementations of the third aspect, the fourth aspect, the fifth aspect, the eighth aspect, or the ninth aspect
  • the inter-frame prediction device according to the above method.
  • a video image decoder includes any of the feasible implementations of the third aspect, the fourth aspect, the fifth aspect, the eighth aspect, or the ninth aspect.
  • the inter-frame prediction device according to the above method.
  • the name of the inter prediction device does not limit the device itself, and in actual implementation, these devices may appear under other names. As long as the functions of each device are similar to the embodiments of the present application, they fall within the scope of the claims of the present application and their equivalent technologies.
  • an embodiment of the present application provides an inter-frame prediction method, including: after obtaining the CPMVD and CPMVP of the image block to be processed, shifting the CPMVD to the left by a first offset value, and shifting the CPMVP to the left by a second offset Shift value, add the left-shifted CPMVD and left-shifted CPMVP to obtain the control point motion vector; according to the control point motion vector, derive the motion vector of each motion compensation unit in the image block to be processed; based on each The motion vectors of each motion compensation unit obtain the reconstruction block of the image block to be processed.
  • the first offset value is 0, and when the accuracy of CPMVP is equal to the first motion vector accuracy, the second offset value is 0.
  • the inter prediction method provided by the embodiment of the present application can improve the accuracy of inter prediction of the coding block using the affine motion model by improving the accuracy and bit depth of the motion vector of the control point and performing motion compensation.
  • the first offset value is equal to 0; when the accuracy of CPMVD is 1/4 pixel accuracy, the first An offset value is equal to 2; when the precision of CPMVD is the precision of whole pixels, the first offset value is equal to 4; when the precision of CPMVP is 1/16 pixel precision, the second offset value is equal to 0; when the precision of CPMVP is At 1/4 pixel accuracy, the second offset value is equal to 2; when the accuracy of CPMVP is full pixel accuracy, the second offset value is equal to 4.
  • the method further includes: when the bit depth of the motion vector of the control point is greater than the bit depth of the first motion vector, clamping the motion vector of the control point so that the bit depth of the motion vector of the control point is equal to the first A motion vector bit depth.
  • the method further includes: clamping the motion vector of the control point so that the bit depth of the motion vector of the control point is equal to the bit depth of the first motion vector.
  • the method further includes: processing the motion vector of the motion compensation unit to meet the preset second motion vector accuracy; and storing the processed motion vector of the motion compensation unit.
  • processing the motion vector of the motion compensation unit includes: shifting the motion vector of the motion compensation unit to the left by a third offset value.
  • it further includes: clamping the bit depth of the motion vector of the processed motion compensation unit so that the bit depth of the motion vector of the processed motion compensation unit is equal to the bit depth of the second motion vector.
  • the method further includes: when the bit depth of the motion vector of the processed motion compensation unit is greater than the bit depth of the second motion vector, clamping the motion vector of the processed motion compensation unit to enable the processing The bit depth of the motion vector of the subsequent motion compensation unit is equal to the bit depth of the second motion vector.
  • the third offset value is equal to 2; when the motion vector of the motion compensation unit When the accuracy is 1/4 pixel accuracy, the third offset value is equal to 0; when the accuracy of the motion vector of the motion compensation unit is 1/32 pixel accuracy, the third offset value is equal to 3.
  • obtaining the reconstruction block of the image block to be processed based on the motion vector of each motion compensation unit includes: performing motion compensation based on the motion vector of each motion compensation unit to obtain the image to be processed The prediction block of the block; based on the prediction block and the motion vector of each motion compensation unit, a reconstructed block of the image block to be processed is obtained.
  • an embodiment of the present application provides an apparatus for inter prediction, including: an acquisition module for acquiring a motion vector difference value CPMVD of a control point of a to-be-processed image block and a prediction value CPMVP of a motion vector of a control point ;
  • the acquisition module is also used to shift the CPMVD to the left by the first offset value, where, when the accuracy of the CPMVD is equal to the first motion vector accuracy, the first offset value is 0;
  • the acquisition module is also used to shift the CPMVP to the left Two offset values, where the second offset value is 0 when the accuracy of CPMVP is equal to the first motion vector accuracy;
  • the acquisition module is also used to add the left-shifted CPMVD and the left-shifted CPMVP to obtain The motion vector of the control point;
  • the calculation module used to derive the motion vector of each motion compensation unit in the image block to be processed according to the motion vector of the control point;
  • the reconstruction module used to obtain the pending vector based on the motion vector of
  • the first offset value is equal to 0; when the accuracy of CPMVD is 1/4 pixel accuracy, the first An offset value is equal to 2; when the precision of CPMVD is the precision of whole pixels, the first offset value is equal to 4; when the precision of CPMVP is 1/16 pixel precision, the second offset value is equal to 0; when the precision of CPMVP is At 1/4 pixel accuracy, the second offset value is equal to 2; when the accuracy of CPMVP is full pixel accuracy, the second offset value is equal to 4.
  • the acquisition module is further used to: when the bit depth of the motion vector of the control point is greater than the bit depth of the first motion vector, clamp the motion vector of the control point to make the bit of the motion vector of the control point The depth is equal to the first motion vector bit depth.
  • the acquisition module is further used to: clamp the motion vector of the control point so that the bit depth of the motion vector of the control point is equal to the bit depth of the first motion vector.
  • the acquisition module is also used to process the motion vector of the motion compensation unit to meet the preset second motion vector accuracy; the device further includes a storage module.
  • the storage module is used to store the processed motion vector of the motion compensation unit.
  • the acquisition module is used to shift the motion vector of the motion compensation unit to the left by a third offset value.
  • the acquisition module is further used to: clamp the bit depth of the motion vector of the processed motion compensation unit to make the bit depth of the motion vector of the processed motion compensation unit equal to the second motion vector Bit depth.
  • the acquisition module is further used to: when the bit depth of the motion vector of the processed motion compensation unit is greater than the bit depth of the second motion vector, clamp the motion vector of the processed motion compensation unit In order to make the bit depth of the motion vector of the processed motion compensation unit equal to the bit depth of the second motion vector.
  • the third offset value is equal to 2; when the motion vector of the motion compensation unit When the accuracy is 1/4 pixel accuracy, the third offset value is equal to 0; when the accuracy of the motion vector of the motion compensation unit is 1/32 pixel accuracy, the third offset value is equal to 3.
  • the reconstruction module is specifically used to: perform motion compensation based on the motion vector of each motion compensation unit to obtain a prediction block of the image block to be processed; based on the prediction block and each motion compensation unit Motion vectors to obtain reconstructed blocks of image blocks to be processed.
  • an embodiment of the present application provides an inter-frame prediction device, including: a processor and a memory coupled to the processor; the processor is used to perform the first aspect, the second aspect, and the sixth aspect In any one of the feasible implementation manners of the aspect, the seventh aspect, or the fifteenth aspect.
  • a computer-readable storage medium in which instructions are stored, and when the instructions run on a computer, the computer is caused to perform the first aspect, the second aspect, The method for inter prediction according to any feasible implementation manner of the sixth aspect, the seventh aspect, or the fifteenth aspect.
  • a nineteenth aspect of the present application provides a computer program product containing instructions, which when executed on a computer, causes the computer to execute the first aspect, the second aspect, the sixth aspect, the seventh aspect, or the tenth Any one of the five possible implementation methods of inter prediction.
  • a video image encoder including any of the above third, fourth, fifth, eighth, ninth or sixteenth aspects A device for implementing inter prediction in a feasible implementation manner.
  • a video image decoder including the above-mentioned third aspect, fourth aspect, fifth aspect, eighth aspect, ninth aspect, or sixteenth aspect
  • An apparatus for implementing inter prediction in any feasible implementation manner is provided.
  • the name of the inter prediction device does not limit the device itself, and in actual implementation, these devices may appear under other names. As long as the functions of each device are similar to the embodiments of the present application, they fall within the scope of the claims of the present application and their equivalent technologies.
  • 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 provided by an embodiment of the present application;
  • FIG. 1B is a block diagram of an example of a video decoding system 40 for implementing an embodiment of the present invention provided by an embodiment of the present application;
  • FIG. 2 is a block diagram of an example structure of an encoder 20 for implementing an embodiment of the present invention provided by an embodiment of the present application;
  • FIG. 3 is a block diagram of an example structure of a decoder 30 for implementing an embodiment of the present invention provided by an embodiment of the present application;
  • FIG. 4 is a block diagram of an example of a video decoding device 400 for implementing an embodiment of the present invention provided by an embodiment of the present application;
  • FIG. 5 is a block diagram of another example of an encoding device or a decoding device used to implement an embodiment of the present invention, provided by an embodiment of the present application;
  • FIG. 6 is an exemplary schematic diagram for representing candidate motion information in the spatial and temporal domains of a current block provided by an embodiment of the present application
  • FIG. 7 is an exemplary schematic diagram for acquiring motion information of an affine model provided by an embodiment of the present application.
  • FIG. 8 is an exemplary schematic diagram of a constructed control point motion vector prediction method provided by an embodiment of the present application.
  • FIG. 9 is a flowchart of an inter prediction method according to an embodiment of the present application.
  • FIG. 11 is a structural example diagram of an apparatus for inter prediction provided by an embodiment of the present application.
  • FIG. 12 is a structural example diagram of another apparatus for inter prediction provided by an embodiment of the present application.
  • the corresponding device may contain one or more units such as functional units to perform the one or more method steps described (eg, one unit performs one or more steps , Or multiple units, each of which performs one or more of multiple steps), even if such one or more units are not explicitly described or illustrated in the drawings.
  • the corresponding method may include a step to perform the functionality of one or more units (eg, one step executes one or more units Functionality, or multiple steps, each of which performs the functionality of one or more of the multiple units), even if such one or more steps are not explicitly described or illustrated in the drawings.
  • the features of the exemplary embodiments and/or aspects described herein may be combined with each other.
  • Video coding generally refers to processing a sequence of pictures that form a video or video sequence.
  • picture In the field of video coding, the terms “picture”, “frame” or “image” may be used as synonyms.
  • Video coding as used herein means video coding or video decoding.
  • Video encoding is performed on the source side, and usually includes processing (eg, by compressing) the original video picture to reduce the amount of data required to represent the video picture, thereby storing and/or transmitting more efficiently.
  • Video decoding is performed on the destination side and usually involves inverse processing relative to the encoder to reconstruct the video picture.
  • the “encoding” of video pictures involved in the embodiments should be understood as referring to the “encoding” or “decoding” of video sequences.
  • the combination of the encoding part and the decoding part is also called codec (encoding and decoding).
  • the video sequence includes a series of pictures, which are further divided into slices, and the slices are further divided into blocks.
  • Video coding is performed in units of blocks.
  • the concept of blocks is further expanded.
  • macroblock macroblock, MB
  • HEVC high-efficiency video coding
  • basic concepts such as coding unit (CU), prediction unit (PU) and transform unit (TU) are adopted.
  • CU coding unit
  • PU prediction unit
  • TU transform unit
  • the CU can be divided into smaller CUs according to the quadtree, and the smaller CU can be further divided to form a quadtree structure.
  • the CU is the basic unit for dividing and coding the coded image.
  • PU can correspond to the prediction block and is the basic unit of predictive coding.
  • the CU is further divided into multiple PUs according to the division mode.
  • the TU can correspond to the transform block and is the basic unit for transforming the prediction residual.
  • PU or TU they all belong to the concept of block (or image block) in essence.
  • the CTU is split into multiple CUs by using a quadtree structure represented as a coding tree.
  • a decision is made at the CU level whether to use inter-picture (temporal) or intra-picture (spatial) prediction to encode the picture area.
  • Each CU can be further split into one, two, or four PUs according to the PU split type.
  • the same prediction process is applied within a PU, and related information is transmitted to the decoder on the basis of the PU.
  • the CU may be divided into transform units (TU) according to other quadtree structures similar to the coding tree used for the CU.
  • quad-tree and binary-tree (Quad-tree and binary tree, QTBT) split frames are used to split the coding blocks.
  • the CU may have a square or rectangular shape.
  • the image block to be encoded in the current encoded image may be referred to as the current block.
  • the reference block is a block that provides a reference signal for the current block, where the reference signal represents a pixel value within the image block.
  • the block in the reference image that provides the prediction signal for the current block may be a prediction block, where the prediction signal represents a pixel value or a sample value or a sample signal within the prediction block. For example, after traversing multiple reference blocks, the best reference block is found. This best reference block will provide a prediction for the current block. This block is called a prediction block.
  • the original video picture can be reconstructed, that is, the reconstructed video picture has the same quality as the original video picture (assuming no transmission loss or other data loss during storage or transmission).
  • further compression is performed by, for example, quantization to reduce the amount of data required to represent the video picture, but the decoder side cannot fully reconstruct the video picture, that is, the quality of the reconstructed video picture is better than the original video picture. The quality is lower or worse.
  • Several video coding standards of H.261 belong to "lossy hybrid video codec” (ie, combining spatial and temporal prediction in the sample domain with 2D transform coding for applying quantization in the transform domain).
  • Each picture of a video sequence is usually divided into non-overlapping block sets, which are usually encoded at the block level.
  • the encoder side usually processes the encoded video at the block (video block) level.
  • the prediction block is generated by spatial (intra-picture) prediction and temporal (inter-picture) prediction.
  • the encoder duplicates the decoder processing loop so that the encoder and decoder generate the same prediction (eg, intra prediction and inter prediction) and/or reconstruction for processing, ie, encoding subsequent blocks.
  • FIG. 1A exemplarily shows a schematic block diagram of a video encoding and decoding system 10 applied in an embodiment of the present application.
  • the video encoding and decoding system 10 may include a source device 12 and a destination device 14, the source device 12 generates encoded video data, and therefore, the source device 12 may be referred to as a video encoding device.
  • the destination device 14 may decode the encoded video data generated by the source device 12, and therefore, the destination device 14 may be referred to as a video decoding device.
  • Various implementations of source device 12, destination device 14, or both may include one or more processors and memory coupled to the one or more processors.
  • Source device 12 and destination device 14 may include various devices, including desktop computers, mobile computing devices, notebook (eg, laptop) computers, tablet computers, set-top boxes, telephone handsets such as so-called "smart" phones, etc. Devices, televisions, cameras, display devices, digital media players, video game consoles, in-vehicle computers, wireless communication devices, or the like.
  • FIG. 1A illustrates the source device 12 and the destination device 14 as separate devices
  • device embodiments may also include the functionality of the source device 12 and the destination device 14 or both, ie the source device 12 or the corresponding Functionality of the destination device 14 or the corresponding functionality.
  • the same hardware and/or software may be used, or separate hardware and/or software, or any combination thereof may be used to implement the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality .
  • the communication connection between the source device 12 and the destination device 14 may be via a link 13, and the destination device 14 may receive the encoded video data from the source device 12 via the link 13.
  • Link 13 may include one or more media or devices capable of moving encoded video data from source device 12 to destination device 14.
  • link 13 may include one or more communication media that enable source device 12 to transmit encoded video data directly to destination device 14 in real time.
  • the source device 12 may modulate the encoded video data according to a communication standard (eg, a wireless communication protocol), and may transmit the modulated video data to the destination device 14.
  • the one or more communication media may include wireless and/or wired communication media, such as a radio frequency (RF) spectrum or one or more physical transmission lines.
  • RF radio frequency
  • the one or more communication media may form part of a packet-based network, such as a local area network, a wide area network, or a global network (eg, the Internet).
  • the one or more communication media may include routers, switches, base stations, or other devices that facilitate communication from source device 12 to destination device 14.
  • the source device 12 includes an encoder 20.
  • the source device 12 may further include a picture source 16, a picture pre-processor 18, and a communication interface 22.
  • the encoder 20, the picture source 16, the picture pre-processor 18, and the communication interface 22 may be hardware components in the source device 12, or may be software programs in the source device 12. They are described as follows:
  • Picture source 16 which can include or can be any type of picture capture device, for example to capture real-world pictures, and/or any type of picture or comment (for screen content encoding, some text on the screen is also considered to be encoded Part of the picture or image) generation device, for example, a computer graphics processor for generating computer animation pictures, or for acquiring and/or providing real-world pictures, computer animation pictures (for example, screen content, virtual reality, VR) pictures) in any category of equipment, and/or any combination thereof (eg, augmented reality (AR) pictures).
  • the picture source 16 may be a camera for capturing pictures or a memory for storing pictures.
  • the picture source 16 may also include any type of (internal or external) interface that stores previously captured or generated pictures and/or acquires or receives pictures.
  • the picture source 16 When the picture source 16 is a camera, the picture source 16 may be, for example, a local or integrated camera integrated in the source device; when the picture source 16 is a memory, the picture source 16 may be a local or integrated, for example, integrated in the source device Memory.
  • the interface When the picture source 16 includes an interface, the interface may be, for example, an external interface that receives pictures from an external video source.
  • the external video source is, for example, an external picture capture device, such as a camera, an external memory, or an external picture generation device.
  • the external picture generation device for example It is an external computer graphics processor, computer or server.
  • the interface may be any type of interface according to any proprietary or standardized interface protocol, such as a wired or wireless interface, an optical interface.
  • the picture can be regarded as a two-dimensional array or matrix of picture elements.
  • the pixels in the array can also be called sampling points.
  • the number of sampling points in the horizontal and vertical directions (or axes) of the array or picture defines the size and/or resolution of the picture.
  • three color components are usually used, that is, a picture can be represented or contain three sampling arrays.
  • the picture includes corresponding red, green, and blue sampling arrays.
  • each pixel is usually expressed in a luminance/chrominance format or color space. For example, for a picture in YUV format, it includes the luminance component indicated by Y (sometimes can also be indicated by L) and the two indicated by U and V.
  • the luma component Y represents luminance or gray-scale horizontal intensity (for example, both are the same in gray-scale pictures), and the two chroma components U and V represent chroma or color information components.
  • the picture in the YUV format includes a luminance sampling array of luminance sampling values (Y), and two chrominance sampling arrays of chrominance values (U and V). RGB format pictures can be converted or transformed into YUV format and vice versa, this process is also called color transformation or conversion. If the picture is black and white, the picture may include only the brightness sampling array.
  • the picture transmitted from the picture source 16 to the picture processor may also be referred to as original picture data 17.
  • the picture pre-processor 18 is configured to receive the original picture data 17 and perform pre-processing on the original picture data 17 to obtain the pre-processed picture 19 or the pre-processed picture data 19.
  • the pre-processing performed by the picture pre-processor 18 may include trimming, color format conversion (eg, conversion from RGB format to YUV format), color grading, or denoising.
  • the encoder 20 (or video encoder 20) is used to receive the pre-processed picture data 19, and process the pre-processed picture data 19 in a related prediction mode (such as the prediction mode in various embodiments herein), thereby
  • the encoded picture data 21 is provided (the structural details of the encoder 20 will be further described below based on FIG. 2 or FIG. 4 or FIG. 5).
  • the encoder 20 may be used to implement various embodiments described below to implement the application of the chroma block prediction method described in this application on the encoding side.
  • the communication interface 22 can be used to receive the encoded picture data 21, and can transmit the encoded picture data 21 to the destination device 14 or any other device (such as a memory) via the link 13 for storage or direct reconstruction.
  • the other device may be any device used for decoding or storage.
  • the communication interface 22 may be used, for example, to encapsulate the encoded picture data 21 into a suitable format, such as a data packet, for transmission on the link 13.
  • the destination device 14 includes a decoder 30, and optionally, the destination device 14 may further include a communication interface 28, a post-picture processor 32, and a display device 34. They are described as follows:
  • the communication interface 28 may be used to receive the encoded picture data 21 from the source device 12 or any other source, such as a storage device, such as an encoded picture data storage device.
  • the communication interface 28 can be used to transmit or receive the encoded picture data 21 through the link 13 between the source device 12 and the destination device 14 or through any type of network.
  • the link 13 is, for example, a direct wired or wireless connection.
  • a network of a category is, for example, a wired or wireless network or any combination thereof, or a private network and a public network of any category, or any combination thereof.
  • the communication interface 28 may be used, for example, to decapsulate the data packet transmitted by the communication interface 22 to obtain the encoded picture data 21.
  • Both the communication interface 28 and the communication interface 22 may be configured as a one-way communication interface or a two-way communication interface, and may be used, for example, to send and receive messages to establish a connection, confirm and exchange any other communication link and/or for example encoded picture data Information about data transmission.
  • the decoder 30 (or referred to as the decoder 30) is used to receive the encoded picture data 21 and provide the decoded picture data 31 or the decoded picture 31 (hereinafter, the decoder 30 will be further described based on FIG. 3 or FIG. 4 or FIG. 5 Structural details).
  • the decoder 30 may be used to execute various embodiments described below to implement the application of the chroma block prediction method described in the present application on the decoding side.
  • the post-picture processor 32 is configured to perform post-processing on the decoded picture data 31 (also referred to as reconstructed picture data) to obtain post-processed picture data 33.
  • the post-processing performed by the image post-processor 32 may include: color format conversion (for example, conversion from YUV format to RGB format), color adjustment, retouching or resampling, or any other processing, and may also be used to convert the post-processed image data 33transmitted to the display device 34.
  • the display device 34 is used to receive post-processed picture data 33 to display pictures to, for example, a user or a viewer.
  • the display device 34 may be or may include any type of display for presenting reconstructed pictures, for example, an integrated or external display or monitor.
  • the display may include a liquid crystal display (LCD), an organic light emitting diode (OLED) display, a plasma display, a projector, a micro LED display, a liquid crystal on silicon (LCoS), Digital light processor (digital light processor, DLP) or any other type of display.
  • FIG. 1A illustrates the source device 12 and the destination device 14 as separate devices
  • device embodiments may also include the functionality of the source device 12 and the destination device 14 or both, ie, the source device 12 or The corresponding functionality and the destination device 14 or corresponding functionality.
  • the same hardware and/or software may be used, or separate hardware and/or software, or any combination thereof may be used to implement the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality .
  • Source device 12 and destination device 14 may include any of a variety of devices, including any type of handheld or stationary devices, such as notebook or laptop computers, mobile phones, smartphones, tablets or tablet computers, cameras, desktops Computers, set-top boxes, televisions, cameras, in-vehicle devices, display devices, digital media players, video game consoles, video streaming devices (such as content service servers or content distribution servers), broadcast receiver devices, broadcast transmitter devices And so on, and can not use or use any kind of operating system.
  • handheld or stationary devices such as notebook or laptop computers, mobile phones, smartphones, tablets or tablet computers, cameras, desktops Computers, set-top boxes, televisions, cameras, in-vehicle devices, display devices, digital media players, video game consoles, video streaming devices (such as content service servers or content distribution servers), broadcast receiver devices, broadcast transmitter devices And so on, and can not use or use any kind of operating system.
  • Both the encoder 20 and the decoder 30 can be implemented as any of various suitable circuits, for example, one or more microprocessors, digital signal processors (DSPs), application-specific integrated circuits (application-specific integrated circuits) circuit, ASIC), field-programmable gate array (FPGA), discrete logic, hardware, or any combination thereof.
  • DSPs digital signal processors
  • ASIC application-specific integrated circuits
  • FPGA field-programmable gate array
  • the device may store the instructions of the software in a suitable non-transitory computer-readable storage medium, and may use one or more processors to execute the instructions in hardware to perform the techniques of the present disclosure . Any one of the foregoing (including hardware, software, a combination of hardware and software, etc.) may be regarded as one or more processors.
  • the video encoding and decoding system 10 shown in FIG. 1A is only an example, and the technology of the present application may be applied to video encoding settings that do not necessarily include any data communication between encoding and decoding devices (eg, video encoding or video decoding).
  • data can be retrieved from local storage, streamed on the network, and so on.
  • the video encoding device may encode the data and store the data to the memory, and/or the video decoding device may retrieve the data from the memory and decode the data.
  • encoding and decoding are performed by devices that do not communicate with each other but only encode data to and/or retrieve data from memory and decode the data.
  • FIG. 1B is an explanatory diagram of an example of a video coding system 40 including the encoder 20 of FIG. 2 and/or the decoder 30 of FIG. 3, according to an exemplary embodiment.
  • the video decoding system 40 can implement a combination of various technologies in the embodiments of the present application.
  • the video decoding system 40 may include an imaging device 41, an encoder 20, a decoder 30 (and/or a video encoder/decoder implemented by the logic circuit 47 of the processing unit 46), an antenna 42 , One or more processors 43, one or more memories 44, and/or display devices 45.
  • the imaging device 41, the antenna 42, the processing unit 46, the logic circuit 47, the encoder 20, the decoder 30, the processor 43, the memory 44, and/or the display device 45 can communicate with each other.
  • the video coding system 40 is shown with the encoder 20 and the decoder 30, in different examples, the video coding system 40 may include only the encoder 20 or only the decoder 30.
  • antenna 42 may be used to transmit or receive an encoded bitstream of video data.
  • the display device 45 may be used to present video data.
  • the logic circuit 47 may be implemented by the processing unit 46.
  • the processing unit 46 may include application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, and the like.
  • the video decoding system 40 may also include an optional processor 43, which may similarly include application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, and the like.
  • the logic circuit 47 may be implemented by hardware, such as dedicated hardware for video encoding, etc., and the processor 43 may be implemented by general-purpose software, an operating system, or the like.
  • the memory 44 may be any type of memory, such as volatile memory (for example, static random access memory (Static Random Access Memory, SRAM), dynamic random access memory (Dynamic Random Access Memory, DRAM), etc.) or non-volatile Memory (for example, flash memory, etc.), etc.
  • volatile memory for example, static random access memory (Static Random Access Memory, SRAM), dynamic random access memory (Dynamic Random Access Memory, DRAM), etc.
  • non-volatile Memory for example, flash memory, etc.
  • the memory 44 may be implemented by cache memory.
  • the logic circuit 47 can access the memory 44 (eg, to implement an image buffer).
  • the logic circuit 47 and/or the processing unit 46 may include memory (eg, cache, etc.) for implementing image buffers and the like.
  • the encoder 20 implemented by logic circuits may include an image buffer (eg, implemented by the processing unit 46 or the memory 44) and a graphics processing unit (eg, implemented by the processing unit 46).
  • the graphics processing unit may be communicatively coupled to the image buffer.
  • the graphics processing unit may include the encoder 20 implemented by a logic circuit 47 to implement the various modules discussed with reference to FIG. 2 and/or any other encoder system or subsystem described herein.
  • Logic circuits can be used to perform the various operations discussed herein.
  • decoder 30 may be implemented by logic circuit 47 in a similar manner to implement the various modules discussed with reference to decoder 30 of FIG. 3 and/or any other decoder systems or subsystems described herein.
  • the decoder 30 implemented by the logic circuit may include an image buffer (implemented by the processing unit 46 or the memory 44) and a graphics processing unit (for example, implemented by the processing unit 46).
  • the graphics processing unit may be communicatively coupled to the image buffer.
  • the graphics processing unit may include a decoder 30 implemented by a logic circuit 47 to implement various modules discussed with reference to FIG. 3 and/or any other decoder system or subsystem described herein.
  • antenna 42 may be used to receive an encoded bitstream of video data.
  • the encoded bitstream may include data related to encoded video frames, indicators, index values, mode selection data, etc. discussed herein, such as data related to encoded partitions (eg, transform coefficients or quantized transform coefficients , (As discussed) optional indicators, and/or data defining the code segmentation).
  • the video coding system 40 may also include a decoder 30 coupled to the antenna 42 and used to decode the encoded bitstream.
  • the display device 45 is used to present video frames.
  • the decoder 30 may be used to perform the reverse process.
  • the decoder 30 may be used to receive and parse such syntax elements and decode the relevant video data accordingly.
  • encoder 20 may entropy encode syntax elements into an encoded video bitstream. In such instances, decoder 30 may parse such syntax elements and decode the relevant video data accordingly.
  • the method described in the embodiment of the present application is mainly used in the inter prediction process. This process exists in both the encoder 20 and the decoder 30.
  • the encoder 20 and the decoder 30 in the embodiment of the present application may be, for example, H .263, H.264, HEVV, MPEG-2, MPEG-4, VP8, VP9 and other video standard protocols or next-generation video standard protocols (such as H.266, etc.) corresponding codec/decoder.
  • FIG. 2 shows a schematic/conceptual block diagram of an example of an encoder 20 for implementing an embodiment of the present application.
  • the encoder 20 includes a residual calculation unit 204, a transform processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transform processing unit 212, a reconstruction unit 214, a buffer 216, a loop filter Unit 220, decoded picture buffer (DPB) 230, prediction processing unit 260, and entropy encoding unit 270.
  • the prediction processing unit 260 may include an inter prediction unit 244, an intra prediction unit 254, and a mode selection unit 262.
  • the inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown).
  • the encoder 20 shown in FIG. 2 may also be referred to as a hybrid video encoder or a video encoder based on a hybrid video codec.
  • the residual calculation unit 204, the transform processing unit 206, the quantization unit 208, the prediction processing unit 260, and the entropy encoding unit 270 form the forward signal path of the encoder 20, while, for example, the inverse quantization unit 210, the inverse transform processing unit 212, the heavy
  • the structural unit 214, the buffer 216, the loop filter 220, the decoded picture buffer (DPB) 230, and the prediction processing unit 260 form a backward signal path of the encoder, where the backward signal path of the encoder corresponds The signal path of the decoder (see decoder 30 in FIG. 3).
  • the encoder 20 receives a picture 201 or an image block 203 of the picture 201 through, for example, an input 202, for example, a picture in a picture sequence forming a video or a video sequence.
  • the image block 203 may also be called a current picture block or a picture block to be encoded
  • the picture 201 may be called a current picture or a picture to be encoded (especially when the current picture is distinguished from other pictures in video encoding, the other pictures are the same video sequence, for example That is, the previously encoded and/or decoded pictures in the video sequence of the current picture are also included).
  • An embodiment of the encoder 20 may include a division unit (not shown in FIG. 2) for dividing the picture 201 into a plurality of blocks such as image blocks 203, usually into a plurality of non-overlapping blocks.
  • the segmentation unit can be used to use the same block size and corresponding grids that define the block size for all pictures in the video sequence, or to change the block size between pictures or subsets or picture groups, and divide each picture into The corresponding block.
  • the prediction processing unit 260 of the encoder 20 may be used to perform any combination of the above-mentioned segmentation techniques.
  • image block 203 is also or can be regarded as a two-dimensional array or matrix of sampling points with sample values, although its size is smaller than picture 201.
  • the image block 203 may include, for example, one sampling array (for example, the brightness array in the case of black and white picture 201) or three sampling arrays (for example, one brightness array and two chroma arrays in the case of color picture) or An array of any other number and/or category depending on the color format applied.
  • the number of sampling points in the horizontal and vertical directions (or axes) of the image block 203 defines the size of the image block 203.
  • the encoder 20 shown in FIG. 2 is used to encode the picture 201 block by block, for example, to perform encoding and prediction on each image block 203.
  • the residual calculation unit 204 is used to calculate the residual block 205 based on the picture image block 203 and the prediction block 265 (other details of the prediction block 265 are provided below), for example, by subtracting the sample value of the image block 203 sample by sample (pixel by pixel) The sample values of the block 265 are predicted to obtain the residual block 205 in the sample domain.
  • the transform processing unit 206 is used to apply a transform such as discrete cosine transform (DCT) or discrete sine transform (DST) on the sample values of the residual block 205 to obtain transform coefficients 207 in the transform domain .
  • the transform coefficient 207 may also be called a transform residual coefficient, and represents a residual block 205 in the transform domain.
  • the transform processing unit 206 may be used to apply integer approximations of DCT/DST, such as the transform specified by HEVC/H.265. Compared with the orthogonal DCT transform, this integer approximation is usually scaled by a factor. In order to maintain the norm of the residual block processed by the forward and inverse transform, an additional scaling factor is applied as part of the transform process.
  • the scaling factor is usually selected based on certain constraints. For example, the scaling factor is a power of two used for the shift operation, the bit depth of the transform coefficient, the accuracy, and the trade-off between implementation cost, and so on.
  • a specific scaling factor can be specified for the inverse transform by the inverse transform processing unit 212 on the decoder 30 side (and corresponding inverse transform by the inverse transform processing unit 212 on the encoder 20 side), and accordingly, the encoder can be The 20 side specifies a corresponding scaling factor for the positive transform through the transform processing unit 206.
  • the quantization unit 208 is used to quantize the transform coefficient 207 by, for example, applying scalar quantization or vector quantization to obtain the quantized transform coefficient 209.
  • the quantized transform coefficient 209 may also be referred to as a quantized residual coefficient 209.
  • the quantization process can reduce the bit depth associated with some or all of the transform coefficients 207. For example, n-bit transform coefficients can be rounded down to m-bit transform coefficients during quantization, where n is greater than m.
  • the degree of quantization can be modified by adjusting quantization parameters (QP). For example, for scalar quantization, different scales can be applied to achieve thinner or coarser quantization.
  • QP quantization parameters
  • a smaller quantization step size corresponds to a finer quantization
  • a larger quantization step size corresponds to a coarser quantization.
  • a suitable quantization step size can be indicated by a quantization parameter (QP).
  • the quantization parameter may be an index of a predefined set of suitable quantization steps.
  • smaller quantization parameters may correspond to fine quantization (smaller quantization step size)
  • larger quantization parameters may correspond to coarse quantization (larger quantization step size)
  • the quantization may include dividing by the quantization step size and the corresponding quantization or inverse quantization performed by the inverse quantization unit 210, for example, or may include multiplying the quantization step size.
  • Embodiments according to some standards such as HEVC may use quantization parameters to determine the quantization step size.
  • the quantization step size can be calculated based on the quantization parameter using a fixed-point approximation including an equation of division. Additional scaling factors can be introduced for quantization and inverse quantization to restore the norm of the residual block that may be modified due to the scale used in fixed-point approximation of the equations for quantization step size and quantization parameter.
  • the scale of inverse transform and inverse quantization may be combined.
  • a custom quantization table can be used and signaled from the encoder to the decoder in the bitstream, for example.
  • Quantization is a lossy operation, where the larger the quantization step, the greater the loss.
  • the inverse quantization unit 210 is used to apply the inverse quantization of the quantization unit 208 on the quantized coefficients to obtain the inverse quantization coefficients 211, for example, based on or using the same quantization step size as the quantization unit 208, apply the quantization scheme applied by the quantization unit 208 Inverse quantization scheme.
  • the inverse quantized coefficient 211 may also be referred to as an inverse quantized residual coefficient 211, which corresponds to the transform coefficient 207, although the loss due to quantization is usually not the same as the transform coefficient.
  • the inverse transform processing unit 212 is used to apply the inverse transform of the transform applied by the transform processing unit 206, for example, an inverse discrete cosine transform (DCT) or an inverse discrete sine transform (DST), in the sample domain
  • the inverse transform block 213 is obtained.
  • the inverse transform block 213 may also be referred to as an inverse transform dequantized block 213 or an inverse transform residual block 213.
  • the reconstruction unit 214 (eg, summer 214) is used to add the inverse transform block 213 (ie, the reconstructed residual block 213) to the prediction block 265 to obtain the reconstructed block 215 in the sample domain, for example, The sample values of the reconstructed residual block 213 and the sample values of the prediction block 265 are added.
  • a buffer unit 216 (or simply "buffer" 216), such as a line buffer 216, is used to buffer or store the reconstructed block 215 and corresponding sample values for, for example, intra prediction.
  • the encoder may be used to use the unfiltered reconstructed blocks and/or corresponding sample values stored in the buffer unit 216 for any type of estimation and/or prediction, such as intra prediction.
  • an embodiment of the encoder 20 may be configured such that the buffer unit 216 is used not only to store the reconstructed block 215 for intra prediction 254, but also for the loop filter unit 220 (not shown in FIG. 2) Out), and/or, for example, causing the buffer unit 216 and the decoded picture buffer unit 230 to form a buffer.
  • Other embodiments may be used to use the filtered block 221 and/or blocks or samples from the decoded picture buffer 230 (neither shown in FIG. 2) as an input or basis for intra prediction 254.
  • the loop filter unit 220 (or simply "loop filter” 220) is used to filter the reconstructed block 215 to obtain the filtered block 221, so as to smoothly perform pixel conversion or improve video quality.
  • the loop filter unit 220 is intended to represent one or more loop filters, such as deblocking filters, sample-adaptive offset (SAO) filters, or other filters, such as bilateral filters, Adaptive loop filter (adaptive loop filter, ALF), or sharpening or smoothing filter, or collaborative filter.
  • the loop filter unit 220 is shown as an in-loop filter in FIG. 2, in other configurations, the loop filter unit 220 may be implemented as a post-loop filter.
  • the filtered block 221 may also be referred to as the filtered reconstructed block 221.
  • the decoded picture buffer 230 may store the reconstructed encoding block after the loop filter unit 220 performs a filtering operation on the reconstructed encoding block.
  • Embodiments of the encoder 20 may be used to output loop filter parameters (eg, sample adaptive offset information), for example, directly output or by the entropy encoding unit 270 or any other
  • the entropy encoding unit outputs after entropy encoding, for example, so that the decoder 30 can receive and apply the same loop filter parameters for decoding.
  • the decoded picture buffer (decoded picture buffer, DPB) 230 may be a reference picture memory for storing reference picture data for the encoder 20 to encode video data.
  • DPB 230 can be formed by any of a variety of memory devices, such as dynamic random access memory (dynamic random access memory, DRAM) (including synchronous DRAM (synchronous DRAM, SDRAM), magnetoresistive RAM (magnetoresistive RAM, MRAM), resistive RAM (resistive RAM, RRAM)) or other types of memory devices.
  • DRAM dynamic random access memory
  • DRAM dynamic random access memory
  • MRAM magnetoresistive RAM
  • RRAM resistive RAM
  • the DPB 230 and the buffer 216 may be provided by the same memory device or separate memory devices.
  • a decoded picture buffer (DPB) 230 is used to store the filtered block 221.
  • the decoded picture buffer 230 may be further used to store other previous filtered blocks of the same current picture or different pictures such as previous reconstructed pictures, such as the previously reconstructed and filtered block 221, and may provide the complete previous The reconstructed ie decoded pictures (and corresponding reference blocks and samples) and/or partially reconstructed current pictures (and corresponding reference blocks and samples), for example for inter prediction.
  • a decoded picture buffer (DPB) 230 is used to store the reconstructed block 215.
  • the prediction processing unit 260 also known as the block prediction processing unit 260, is used to receive or acquire the image block 203 (current image block 203 of the current picture 201) and reconstructed picture data, such as the same (current) picture from the buffer 216 Reference samples and/or reference picture data 231 of one or more previously decoded pictures from the decoded picture buffer 230, and used to process such data for prediction, that is, to provide an inter prediction block 245 or The prediction block 265 of the intra prediction block 255.
  • the mode selection unit 262 may be used to select a prediction mode (eg, intra or inter prediction mode) and/or the corresponding prediction block 245 or 255 used as the prediction block 265 to calculate the residual block 205 and reconstruct the reconstructed block 215.
  • a prediction mode eg, intra or inter prediction mode
  • the corresponding prediction block 245 or 255 used as the prediction block 265 to calculate the residual block 205 and reconstruct the reconstructed block 215.
  • An embodiment of the mode selection unit 262 may be used to select a prediction mode (for example, from those prediction modes supported by the prediction processing unit 260), which provides the best match or the minimum residual (the minimum residual means Better compression in transmission or storage), or provide minimum signaling overhead (minimum signaling overhead means better compression in transmission or storage), or consider or balance both at the same time.
  • the mode selection unit 262 may be used to determine a prediction mode based on rate distortion optimization (RDO), that is, to select a prediction mode that provides minimum bit rate distortion optimization, or to select a prediction mode in which the related bit rate distortion at least meets the prediction mode selection criteria .
  • RDO rate distortion optimization
  • the encoder 20 is used to determine or select the best or optimal prediction mode from the (predetermined) prediction mode set.
  • the set of prediction modes may include, for example, intra prediction modes and/or inter prediction modes.
  • the intra prediction mode set may include 35 different intra prediction modes, for example, non-directional modes such as DC (or mean) mode and planar mode, or directional modes as defined in H.265, or may include 67 Different intra prediction modes, for example, non-directional modes such as DC (or mean) mode and planar mode, or directional modes as defined in the developing H.266.
  • non-directional modes such as DC (or mean) mode and planar mode
  • directional modes as defined in the developing H.266.
  • the set of inter prediction modes depends on the available reference pictures (ie, for example, the aforementioned at least partially decoded pictures stored in DBP 230) and other inter prediction parameters, for example, depending on whether the entire reference picture is used or only Use a part of the reference picture, for example the search window area surrounding the area of the current block, to search for the best matching reference block, and/or for example depending on whether pixel interpolation such as half-pixel and/or quarter-pixel interpolation is applied
  • the set of inter prediction modes may include advanced motion vector (Advanced Motion Vector Prediction, AMVP) mode and merge mode.
  • AMVP Advanced Motion Vector Prediction
  • the set of inter-frame prediction modes may include an advanced control point-based advanced motion vector prediction (AMVP) mode improved in the embodiments of the present application, and an improved control point-based merge mode.
  • AMVP advanced control point-based advanced motion vector prediction
  • the intra prediction unit 254 may be used to perform any combination of inter prediction techniques described below.
  • the embodiments of the present application may also apply skip mode and/or direct mode.
  • the prediction processing unit 260 may be further used to split the image block 203 into smaller block partitions or sub-blocks, for example, iteratively using quad-tree (QT) segmentation, binary-tree (BT) segmentation Or triple-tree (TT) partitioning, or any combination thereof, and for performing prediction for each of block partitions or sub-blocks, for example, where mode selection includes selecting the tree structure of the divided image block 203 and selecting the application The prediction mode for each of the block partitions or sub-blocks.
  • QT quad-tree
  • BT binary-tree
  • TT triple-tree
  • the inter prediction unit 244 may include a motion estimation (ME) unit (not shown in FIG. 2) and a motion compensation (MC) unit (not shown in FIG. 2).
  • the motion estimation unit is used to receive or acquire a picture image block 203 (current picture image block 203 of the current picture 201) and a decoded picture 231, or at least one or more previously reconstructed blocks, for example, one or more other/different
  • the reconstructed block of the previously decoded picture 231 is used for motion estimation.
  • the video sequence may include the current picture and the previously decoded picture 31, or in other words, the current picture and the previously decoded picture 31 may be part of the picture sequence forming the video sequence, or form the picture sequence.
  • the encoder 20 may be used to select a reference block from multiple reference blocks of the same or different pictures in multiple other pictures, and provide a reference picture and/or provide a reference to a motion estimation unit (not shown in FIG. 2)
  • the offset (spatial offset) between the position of the block (X, Y coordinates) and the position of the current block is used as an inter prediction parameter.
  • This offset is also called a motion vector (MV).
  • the motion compensation unit is used to acquire inter prediction parameters, and perform inter prediction based on or using inter prediction parameters to obtain inter prediction blocks 245.
  • the motion compensation performed by the motion compensation unit may include extracting or generating a prediction block based on a motion/block vector determined by motion estimation (possibly performing interpolation of sub-pixel accuracy). Interpolation filtering can generate additional pixel samples from known pixel samples, potentially increasing the number of candidate prediction blocks that can be used to encode picture blocks.
  • the motion compensation unit 246 may locate the prediction block pointed to by the motion vector in a reference picture list. Motion compensation unit 246 may also generate syntax elements associated with blocks and video slices for use by decoder 30 when decoding picture blocks of video slices.
  • the above inter prediction unit 244 may transmit a syntax element to the entropy encoding unit 270, where the syntax element includes inter prediction parameters (such as an inter prediction mode selected for the current block prediction after traversing multiple inter prediction modes Instructions).
  • inter prediction parameters such as an inter prediction mode selected for the current block prediction after traversing multiple inter prediction modes Instructions.
  • the decoding terminal 30 may directly use the default prediction mode for decoding. It can be understood that the inter prediction unit 244 may be used to perform any combination of inter prediction techniques.
  • the intra prediction unit 254 is used to acquire, for example, a picture block 203 (current picture block) that receives the same picture and one or more previously reconstructed blocks, such as reconstructed neighboring blocks, for intra estimation.
  • the encoder 20 may be used to select an intra prediction mode from a plurality of (predetermined) intra prediction modes.
  • Embodiments of the encoder 20 may be used to select an intra prediction mode based on optimization criteria, for example, based on a minimum residual (eg, an intra prediction mode that provides the prediction block 255 most similar to the current picture block 203) or minimum rate distortion.
  • a minimum residual eg, an intra prediction mode that provides the prediction block 255 most similar to the current picture block 203
  • minimum rate distortion e.g., a minimum rate distortion
  • the intra prediction unit 254 is further used to determine the intra prediction block 255 based on the intra prediction parameters of the intra prediction mode as selected. In any case, after selecting the intra-prediction mode for the block, the intra-prediction unit 254 is also used to provide the intra-prediction parameters to the entropy encoding unit 270, that is, to provide an indication of the selected intra-prediction mode for the block Information. In one example, the intra prediction unit 254 may be used to perform any combination of intra prediction techniques.
  • the above-mentioned intra-prediction unit 254 may transmit a syntax element to the entropy encoding unit 270, where the syntax element includes intra-prediction parameters (such as an intra-prediction mode selected for the current block prediction after traversing multiple intra-prediction modes) Instructions).
  • the intra prediction parameters may not be carried in the syntax element.
  • the decoding terminal 30 may directly use the default prediction mode for decoding.
  • the entropy coding unit 270 is used to convert the entropy coding algorithm or scheme (for example, variable length coding (VLC) scheme, context adaptive VLC (context adaptive VLC, CAVLC) scheme, arithmetic coding scheme, context adaptive binary arithmetic) Coding (context adaptive) binary arithmetic coding (CABAC), syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval partition entropy (probability interval interpartitioning entropy, PIPE) coding or other entropy Coding method or technique) applied to a single or all of the quantized residual coefficients 209, inter prediction parameters, intra prediction parameters, and/or loop filter parameters (or not applied) to obtain the output 272 to For example, the encoded picture data 21 output in the form of an encoded bit stream 21.
  • VLC variable length coding
  • CABAC context adaptive binary arithmetic) Coding
  • SBAC syntax-based context-adaptive binary arithmetic
  • the encoded bitstream can be transmitted to the video decoder 30 or archived for later transmission or retrieval by the video decoder 30.
  • the entropy encoding unit 270 may also be used to entropy encode other syntax elements of the current video slice being encoded.
  • video encoder 20 may be used to encode video streams.
  • the non-transform based encoder 20 may directly quantize the residual signal without the transform processing unit 206 for certain blocks or frames.
  • the encoder 20 may have a quantization unit 208 and an inverse quantization unit 210 combined into a single unit.
  • the encoder 20 may be used to implement the inter prediction method described in the embodiments below.
  • the video encoder 20 can directly quantize the residual signal without processing by the transform processing unit 206, and accordingly, without processing by the inverse transform processing unit 212; or, for some For image blocks or image frames, the video encoder 20 does not generate residual data, and accordingly does not need to be processed by the transform processing unit 206, quantization unit 208, inverse quantization unit 210, and inverse transform processing unit 212; or, the video encoder 20 may convert The reconstructed image block is directly stored as a reference block without being processed by the loop filter 220; alternatively, the quantization unit 208 and the inverse quantization unit 210 in the video encoder 20 may be merged together.
  • the loop filter 220 is optional, and in the case of lossless compression coding, the transform processing unit 206, quantization unit 208, inverse quantization unit 210, and inverse transform processing unit 212 are optional. It should be understood that the inter prediction unit 244 and the intra prediction unit 254 may be selectively enabled according to different application scenarios.
  • FIG. 3 shows a schematic/conceptual block diagram of an example of a decoder 30 for implementing an embodiment of the present application.
  • the video decoder 30 is used to receive encoded picture data (eg, encoded bitstream) 21, for example, encoded by the encoder 20, to obtain the decoded picture 231.
  • encoded picture data eg, encoded bitstream
  • video decoder 30 receives video data from video encoder 20, such as an encoded video bitstream and associated syntax elements representing picture blocks of the encoded video slice.
  • the decoder 30 includes an entropy decoding unit 304, an inverse quantization unit 310, an inverse transform processing unit 312, a reconstruction unit 314 (such as a summer 314), a buffer 316, a loop filter 320, a The decoded picture buffer 330 and the prediction processing unit 360.
  • the prediction processing unit 360 may include an inter prediction unit 344, an intra prediction unit 354, and a mode selection unit 362.
  • video decoder 30 may perform a decoding pass that is generally inverse to the encoding pass described with reference to video encoder 20 of FIG. 2.
  • the entropy decoding unit 304 is used to perform entropy decoding on the encoded picture data 21 to obtain, for example, quantized coefficients 309 and/or decoded encoding parameters (not shown in FIG. 3), for example, inter prediction, intra prediction parameters , Any or all of the loop filter parameters and/or other syntax elements (decoded).
  • the entropy decoding unit 304 is further used to forward inter prediction parameters, intra prediction parameters, and/or other syntax elements to the prediction processing unit 360.
  • Video decoder 30 may receive syntax elements at the video slice level and/or the video block level.
  • the inverse quantization unit 310 may be functionally the same as the inverse quantization unit 210
  • the inverse transform processing unit 312 may be functionally the same as the inverse transform processing unit 212
  • the reconstruction unit 314 may be functionally the same as the reconstruction unit 214
  • the buffer 316 may be functionally
  • the loop filter 320 may be functionally the same as the loop filter 220
  • the decoded picture buffer 330 may be functionally the same as the decoded picture buffer 230.
  • the prediction processing unit 360 may include an inter prediction unit 344 and an intra prediction unit 354, wherein the inter prediction unit 344 may be similar in function to the inter prediction unit 244, and the intra prediction unit 354 may be similar in function to the intra prediction unit 254 .
  • the prediction processing unit 360 is generally used to perform block prediction and/or to obtain the prediction block 365 from the encoded picture data 21, and to receive or obtain prediction-related parameters and/or about from the entropy decoding unit 304 (explicitly or implicitly) Information about the selected prediction mode.
  • the intra prediction unit 354 of the prediction processing unit 360 is used to signal-based the intra prediction mode and the previous decoded block from the current frame or picture. Data to generate a prediction block 365 for the picture block of the current video slice.
  • the inter prediction unit 344 eg, motion compensation unit
  • Other syntax elements generate a prediction block 365 for the video block of the current video slice.
  • a prediction block may be generated from a reference picture in a reference picture list.
  • the video decoder 30 may construct the reference frame lists: list 0 and list 1 based on the reference pictures stored in the DPB 330 using default construction techniques.
  • the prediction processing unit 360 is used to determine the prediction information for the video block of the current video slice by parsing the motion vector and other syntax elements, and use the prediction information to generate the prediction block for the current video block being decoded.
  • the prediction processing unit 360 uses some received syntax elements to determine the prediction mode (eg, intra or inter prediction) of the video block used to encode the video slice, and the inter prediction slice type ( For example, B slice, P slice, or GPB slice), construction information of one or more of the reference picture lists for slices, motion vectors for each inter-coded video block for slices, The inter prediction status and other information of each inter-coded video block of the slice to decode the video block of the current video slice.
  • the prediction mode eg, intra or inter prediction
  • the inter prediction slice type For example, B slice, P slice, or GPB slice
  • the syntax elements received by the video decoder 30 from the bitstream include an adaptive parameter set (adaptive parameter set, APS), sequence parameter set (SPS), and picture parameter set (picture parameter (set, PPS) or the syntax element in one or more of the stripe headers.
  • adaptive parameter set adaptive parameter set
  • SPS sequence parameter set
  • PPS picture parameter set
  • the inverse quantization unit 310 may be used to inverse quantize (ie, inverse quantize) the quantized transform coefficients provided in the bitstream and decoded by the entropy decoding unit 304.
  • the inverse quantization process may include using the quantization parameters calculated by the video encoder 20 for each video block in the video slice to determine the degree of quantization that should be applied and also determine the degree of inverse quantization that should be applied.
  • the inverse transform processing unit 312 is used to apply an inverse transform (eg, inverse DCT, inverse integer transform, or conceptually similar inverse transform process) to the transform coefficients, so as to generate a residual block in the pixel domain.
  • an inverse transform eg, inverse DCT, inverse integer transform, or conceptually similar inverse transform process
  • the reconstruction unit 314 (eg, summer 314) is used to add the inverse transform block 313 (ie, the reconstructed residual block 313) to the prediction block 365 to obtain the reconstructed block 315 in the sample domain, for example by The sample values of the reconstructed residual block 313 are added to the sample values of the prediction block 365.
  • the loop filter unit 320 (during the encoding loop or after the encoding loop) is used to filter the reconstructed block 315 to obtain the filtered block 321 to smoothly perform pixel conversion or improve video quality.
  • the loop filter unit 320 may be used to perform any combination of filtering techniques described below.
  • the loop filter unit 320 is intended to represent one or more loop filters, such as deblocking filters, sample-adaptive offset (SAO) filters, or other filters, such as bilateral filters, self-adaptive filters Adaptive loop filter (adaptive loop filter, ALF), or sharpening or smoothing filter, or collaborative filter.
  • the loop filter unit 320 is shown as an in-loop filter in FIG. 3, in other configurations, the loop filter unit 320 may be implemented as a post-loop filter.
  • the decoded video block 321 in a given frame or picture is then stored in a decoded picture buffer 330 that stores reference pictures for subsequent motion compensation.
  • the decoder 30 is used, for example, to output the decoded picture 31 through the output 332 for presentation to the user or for the user to view.
  • video decoder 30 may be used to decode the compressed bitstream.
  • the decoder 30 may generate the output video stream without the loop filter unit 320.
  • the non-transform based decoder 30 may directly inversely quantize the residual signal without the inverse transform processing unit 312 for certain blocks or frames.
  • the video decoder 30 may have an inverse quantization unit 310 and an inverse transform processing unit 312 combined into a single unit.
  • the decoder 30 is used to implement the inter prediction method described in the embodiments below.
  • video decoder 30 may be used to decode the encoded video bitstream.
  • the video decoder 30 may generate an output video stream without processing by the filter 320; or, for certain image blocks or image frames, the entropy decoding unit 304 of the video decoder 30 does not decode the quantized coefficients, and accordingly does not It needs to be processed by the inverse quantization unit 310 and the inverse transform processing unit 312.
  • the loop filter 320 is optional; and in the case of lossless compression, the inverse quantization unit 310 and the inverse transform processing unit 312 are optional.
  • the inter prediction unit and the intra prediction unit may be selectively enabled.
  • the processing results for a certain link can be further processed and output to the next link, for example, in interpolation filtering, motion vector derivation or loop filtering, etc. After the link, the results of the corresponding link are further clipped or shift shifted.
  • the motion vector of the control point of the current image block derived from the motion vector of the adjacent affine coding block may be further processed, which is not limited in this application.
  • the value range of the motion vector is constrained to be within a certain bit width. Assuming that the allowed bit width of the motion vector is bit depth (bitDepth), the value range of the motion vector is -2 ⁇ (bitDepth-1) ⁇ 2 ⁇ (bitDepth-1)-1, where the " ⁇ " symbol indicates power square. If bitDepth is 16, the value ranges from -32768 to 32767. If bitDepth is 18, the value range is
  • ux (vx+2 bitDepth )%2 bitDepth
  • the value of vx is -32769, and the value obtained by the above formula is 32767. Because in the computer, the value is stored in the form of two's complement, the complement of -32769 is 1,0111,1111,1111,1111 (17 bits), the computer handles the overflow as discarding the high bit, then the value of vx If it is 0111,1111,1111,1111, it is 32767, which is consistent with the result obtained by formula processing.
  • vx Clip3 (-2 bitDepth-1 , 2 bitDepth-1 -1, vx)
  • Clip3 clamps the value of z to the interval [x, y]:
  • FIG. 4 is a schematic structural diagram of a video decoding device 400 (for example, a video encoding device 400 or a video decoding device 400) provided by an embodiment of the present application.
  • the video coding apparatus 400 is suitable for implementing the embodiments described herein.
  • the video coding device 400 may be a video decoder (eg, decoder 30 of FIG. 1A) or a video encoder (eg, encoder 20 of FIG. 1A).
  • the video decoding device 400 may be one or more components in the decoder 30 of FIG. 1A or the encoder 20 of FIG. 1A described above.
  • the video decoding device 400 includes: an inlet port 410 for receiving data and a receiver unit (Rx) 420, a processor for processing data, a logic unit or a central processing unit (CPU) 430, and a transmitter for transmitting data A unit (Tx) 440 and an exit port 450, and a memory 460 for storing data.
  • the video decoding device 400 may further include a photoelectric conversion component and an electro-optical (EO) component coupled to the inlet port 410, the receiver unit 420, the transmitter unit 440, and the outlet port 450 for the outlet or inlet of the optical signal or the electrical signal.
  • EO electro-optical
  • the processor 430 is implemented by hardware and software.
  • the processor 430 may be implemented as one or more CPU chips, cores (eg, multi-core processors), FPGA, ASIC, and DSP.
  • the processor 430 communicates with the inlet port 410, the receiver unit 420, the transmitter unit 440, the outlet port 450, and the memory 460.
  • the processor 430 includes a decoding module 470 (for example, an encoding module 470 or a decoding module 470).
  • the encoding/decoding module 470 implements the embodiments disclosed herein to implement the chroma block prediction method provided by the embodiments of the present application. For example, the encoding/decoding module 470 implements, processes, or provides various encoding operations.
  • the encoding/decoding module 470 provides a substantial improvement to the function of the video decoding device 400 and affects the conversion of the video decoding device 400 to different states.
  • the encoding/decoding module 470 is implemented with instructions stored in the memory 460 and executed by the processor 430.
  • the memory 460 includes one or more magnetic disks, tape drives, and solid-state hard disks, and can be used as an overflow data storage device for storing programs when these programs are selectively executed, as well as instructions and data read during program execution.
  • the memory 460 may be volatile and/or non-volatile, and may be read only memory (ROM), random access memory (RAM), random access memory (ternary content-addressable memory (TCAM), and/or static Random Access Memory (SRAM).
  • FIG. 5 is a simplified block diagram of an apparatus 500 that can be used as either or both of the source device 12 and the destination device 14 in FIG. 1A according to an exemplary embodiment.
  • the device 500 can implement the technology of the present application.
  • FIG. 5 is a schematic block diagram of an implementation manner of an encoding device or a decoding device (referred to simply as a decoding device 500) according to an embodiment of the present application.
  • the decoding device 500 may include a processor 510, a memory 530, and a bus system 550.
  • the processor and the memory are connected through a bus system, the memory is used to store instructions, and the processor is used to execute the instructions stored in the memory.
  • the memory of the decoding device stores program codes, and the processor can call the program codes stored in the memory to perform various video encoding or decoding methods described in this application. In order to avoid repetition, they are not described in detail here.
  • the processor 510 may be a central processing unit (Central Processing Unit, referred to as "CPU"), and the processor 510 may also be other general-purpose processors, digital signal processors (DSPs), and dedicated integrated Circuit (ASIC), ready-made programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.
  • the general-purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
  • the memory 530 may include a read only memory (ROM) device or a random access memory (RAM) device. Any other suitable type of storage device may also be used as the memory 530.
  • the memory 530 may include code and data 531 accessed by the processor 510 using the bus 550.
  • the memory 530 may further include an operating system 533 and an application program 535 including at least one program that allows the processor 510 to perform the video encoding or decoding method described in this application.
  • the application program 535 may include applications 1 to N, which further include a video encoding or decoding application (referred to as a video coding application for short) that performs the video encoding or decoding method described in this application.
  • the bus system 550 may also include a power bus, a control bus, and a status signal bus. However, for clarity, various buses are marked as the bus system 550 in the figure.
  • the decoding device 500 may also include one or more output devices, such as a display 570.
  • the display 570 may be a tactile display that merges the display with a tactile unit that operably senses touch input.
  • the display 570 may be connected to the processor 510 via the bus 550.
  • AMVP advanced motion vector prediction
  • merge mode In HEVC, two inter prediction modes are used, which are advanced motion vector prediction (advanced motion vector prediction, AMVP) mode and merge mode.
  • AMVP advanced motion vector prediction
  • merge mode In HEVC, two inter prediction modes are used, which are advanced motion vector prediction (advanced motion vector prediction, AMVP) mode and merge mode.
  • the AMVP mode For the AMVP mode, first traverse the coded blocks (referred to as neighboring blocks) adjacent to the spatial or temporal domain of the current block, and construct a candidate motion vector list according to the motion information of each neighboring block.
  • the candidate motion vector list may also be called a motion information candidate list.
  • the optimal motion vector is determined from the candidate motion vector list through the rate distortion cost.
  • the candidate motion information with the lowest rate-distortion cost is determined as the optimal motion vector, and the optimal motion vector is used as the motion vector predictor (MVP) of the current block.
  • MVP motion vector predictor
  • the position of the neighboring block and its traversal order are predefined.
  • the rate-distortion cost can be calculated using formula (1).
  • J represents the rate-distortion cost
  • SAD represents the sum of absolute errors (SAD) between the predicted pixel value and the original pixel value obtained after motion estimation using candidate motion vector prediction values
  • R represents the code rate
  • ⁇ represents the Lagrange 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 the MVP-centered neighborhood to obtain the actual motion vector of the current block, and the encoding end transmits the difference (motion vector difference) between the MVP and the actual motion vector to the decoding end.
  • the Merge mode For the Merge mode, first traverse the coded blocks (referred to as neighbor blocks) adjacent to the current block in the spatial or temporal domain, and construct a candidate motion vector list according to the motion information of each neighbor block. Then, the optimal motion information is determined as the motion vector motion information of the current block from the candidate motion vector list by calculating the rate distortion cost. For details, please refer to the explanation in the above AMVP mode. Then, the index value of the position of the optimal motion information in the candidate motion vector list (may be referred to as merge index) is transferred to the decoding end. For example, the candidate motion information of the current block in the spatial and temporal domains is shown in FIG. 6, and the candidate motion information of the spatial domain is from five spatially adjacent blocks (A0, A1, B0, B1, and B2).
  • the motion information of the neighboring block is not added to the candidate motion vector list.
  • the temporal motion candidate information of the current block is obtained by scaling the MV of the corresponding position block in the reference frame according to the picture order (POC) of the reference frame and the current frame. First determine whether the block at the T position in the reference frame is available, and if not, select the block at the C position.
  • the location and traversal order of neighbor blocks in the Merge mode are also predefined, and the location and traversal order of neighbor blocks may be different in different modes.
  • HEVC inter prediction all pixels in the coding block adopt the same motion information, and then perform motion compensation according to the motion information to obtain the prediction value of the pixels of the coding block.
  • the coding block not all pixels have the same motion characteristics. Using the same motion information may cause inaccurate motion compensation prediction, thereby increasing residual information.
  • the AMVP mode can be divided into an AMVP mode based on the translation model and an AMVP mode based on the non-translation model.
  • Merge mode can be divided into Merge mode based on translation model and Merge mode based on non-translational motion model.
  • Non-translational motion model prediction refers to using the same motion model at the codec to derive the motion information of each sub-motion compensation unit in the current block, performing motion compensation according to the motion information of the sub-motion compensation unit, and obtaining a prediction block. Thus, the prediction efficiency is improved.
  • Commonly used non-translational motion models are 4-parameter affine motion models or 6-parameter affine motion models.
  • the sub-motion compensation unit involved in the embodiment of the present application may be a pixel or a pixel block of a size N 1 ⁇ N 2 divided according to a specific method, where N 1 and N 2 are both positive integers, N 1 may be equal to N 2, it may not be equal to N 2.
  • the 4-parameter affine motion model can be represented by the motion vectors of two pixels and their coordinates relative to the upper 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, the motion vectors (vx0,vy0) and (vx1,vy1) of the control points of the upper left vertex and upper right vertex of the current block are determined first, Then obtain the motion information of each sub-motion compensation unit in the current block according to formula (3), where (x, y) is the coordinate of the sub-motion compensation unit relative to the upper left vertex 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 expressed by the motion vectors of three pixels and their coordinates relative to the upper 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 first Are (vx0, vy0) and (vx1, vy1) and (vx2, vy2), and then get the motion information of each sub-motion compensation unit in the current block according to formula (5), where (x, y) is the sub-motion compensation unit Relative to the coordinates of the upper left vertex pixel of the current block, W and H are the width and height of the current block, respectively.
  • the coding block predicted by the affine motion model is called the affine coding block.
  • the Advanced Motion Vector Prediction (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.
  • AMVP Advanced Motion Vector Prediction
  • the motion information of the control point 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.
  • the inherited control point motion vector prediction method refers to determining the candidate control point motion vectors of the current block using the motion models of adjacent coded affine coding blocks.
  • the adjacent blocks around the current block are traversed to find the neighbors of the current block.
  • the affine coding block where the position block is located obtains the control point motion information of the affine coding block, and then derives the control point for the current block in the Merge mode through the motion model constructed by the affine coding block control point motion information Motion vectors, or derive motion vector prediction values for control points in AMVP mode.
  • A1->B1->B0->A0->B2 is only an example, and the order of other combinations is also applicable to this application.
  • the adjacent position blocks are not limited to A1, B1, B0, A0, and B2.
  • the adjacent position block can be a pixel point, a pixel block of a preset size divided according to a specific method, for example, a 4x4 pixel block, a 4x2 pixel block, or a pixel block of another size, not used limited.
  • the motion vector (vx4, vy4) and the upper right vertex (x5, y5) of the upper left vertex (x4, y4) of the affine coding block are obtained.
  • 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) of the current block obtained based on the affine coding block where A1 is located as above is the current The candidate control point motion vector of the block.
  • the motion vector (vx4, vy4) and the motion vector (vx5, y5) of the upper left vertex (x4, y4) of the affine coding block are obtained.
  • the combination of the motion vectors (vx2, vy2) of the vertices (x2, y2) 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 the coded blocks adjacent to the control point of the current block as the motion vectors of the control points of the current affine coding block, without considering the neighboring neighboring Whether the coding block is an affine coding block.
  • 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 coding block. Take the example shown in FIG. 8 to describe the constructed control point motion vector prediction method. It should be noted that FIG. 8 is only an example.
  • the motion vectors of the coded blocks A2, B2 and B3 adjacent to the upper left vertex are used as the candidate motion vectors of the motion vectors of the upper left vertex of the current block; the motion vectors of the upper right vertex adjacent to the coded blocks B1 and B0 are used
  • the motion vector is a candidate motion vector as the 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 multiple binary groups.
  • the motion vectors of the two encoded blocks included in the binary group can be used as the candidate control point motion vectors of the current block. See the following formula ( 11A) shows:
  • 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 vectors of the coded blocks A2, B2 and B3 adjacent to the upper left vertex are used as the candidate motion vectors of the motion vectors of the upper left vertex of the current block; the motion vectors of the upper right vertex adjacent to the coded blocks B1 and B0 are used
  • the motion vector is the candidate motion vector of the motion vector of the upper right vertex of the current block, and the motion vectors of the encoded blocks A0 and A1 adjacent to the sitting vertex are used as the motion vector candidate of the lower left vertex of the current block.
  • the candidate motion vectors of the upper left vertex, the upper right vertex, and the lower left vertex are combined to form a triplet.
  • the motion vectors of the three encoded blocks included in the triplet can be used as the candidate control point motion vectors of the current block. See the following formula (11B), (11C) shows:
  • 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
  • v A0 represents the motion vector of A0
  • v A1 represents the motion vector of A1.
  • a candidate motion vector list of the AMVP mode based on the affine motion model is constructed.
  • 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 motion vector prediction of each control point
  • the value includes the motion vector of 2 (4-parameter affine motion models) control points or the motion vector of 3 (6-parameter affine motion models) control points.
  • control point motion vector predictor candidate list is pruned and sorted according to specific rules, and it can be truncated or filled to a specific number.
  • the motion vector of each control point in the candidate list of control point motion vector prediction values is used to obtain the motion vector of each sub-motion compensation unit in the current coding block through formula (3) or (5), and then the The pixel value of the corresponding position in the reference frame pointed by the motion vector of the sub motion compensation unit is used as the predicted 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 minimum average value as the optimal control point motion vector prediction value, and use it as the current coding
  • the index number indicating the position of the control point motion vector prediction value in the control point motion vector prediction value candidate list is encoded into the code stream and sent to the decoder.
  • the index number is parsed, and the control point motion vector predictor (CPMVP) is determined from the control point motion vector predictor candidate list according to the index number.
  • CPMVP control point motion vector predictor
  • control point motion vectors are obtained by performing motion search within a certain search range using the control point motion vector prediction value as the search starting point. And the difference between control point motion vector and control point motion vector prediction value (control point motion vectors differences (CPMVD)) is passed to the decoding end.
  • control point motion vectors differences CPMVD
  • the difference of the control point motion vector is analyzed and added to the predicted value of the control point motion vector to obtain the control point motion vector.
  • Affine fusion mode (Affine Merge mode) based on affine motion model:
  • control point motion vector prediction method Use the inherited control point motion vector prediction method and/or the constructed control point motion vector prediction method to construct a control point motion vector fusion candidate list (control point motion vectors merged candidate list).
  • control point motion vector fusion candidate list is pruned and sorted according to specific rules, and it can be truncated or filled to a specific number.
  • each sub-motion compensation unit in the current coding block (the size divided by pixels or a specific method is N 1 ⁇ N) by formula (3) or (5) 2 pixel blocks), and then obtain the pixel value of the position in the reference frame pointed by the motion vector of each sub-motion compensation unit as its predicted value, and perform affine motion compensation.
  • the 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 decoder.
  • the index number is analyzed, and the control point motion vectors (CPMV) are determined from the control point motion vector fusion candidate list according to the index number.
  • CPMV control point motion vectors
  • the range that the MV can represent is (-2 11 , 2 11 -1).
  • the range that the MV can represent is (-2 13 , 2 13 -1).
  • the range that the MV can represent is (-2 13 , 2 13 -1).
  • the accuracy of CPMVD can be 1/16, the bit depth of CPMVD is 16bit, or the accuracy of CPMVD can be 1/4, the bit depth of CPMVD is 16bit, or the accuracy of CPMVD can be integer Pixel accuracy, the bit depth of CPMVD is 16bit.
  • the accuracy of motion information during motion compensation and motion information storage may not be uniform.
  • the present application proposes a method of storage of motion information and precision transformation in motion compensation of the affine coding block. If the accuracy of the motion compensation and the stored motion information are the same, the same motion vector accuracy is adopted; if the accuracy of the motion compensation and the stored motion information are different, the motion vector accuracy of the motion compensation is quantized to the stored motion vector accuracy for storage.
  • FIG. 9 is a flowchart of an inter prediction method according to an embodiment of the present application. Assuming that the image block to be processed is the current affine coding block, as shown in FIG. 9, the method may include:
  • the method for determining the inter prediction mode of the current affine coding block can be obtained by parsing the syntax elements, and the specific determination method is not specifically limited in this application. If it is determined that the inter prediction mode of the current affine coding block is the AMVP mode based on the affine motion model, the following steps are performed.
  • parsing the code stream can obtain the index of the motion vector difference (CPMVD) of the control point and the predicted value of the motion vector of the control point, and predict from the motion vector of the control point according to the index of the predicted value of the motion vector of the control point
  • the value candidate list determines the motion vector prediction value (CPMVP) of the control point.
  • CPMVP can be obtained by acquiring the motion vectors of adjacent coded blocks in the storage unit, adding CPMVD and CPMVP to obtain the motion vector of the control point (CPMV).
  • control point motion vector predictor candidate list is usually stored with low accuracy.
  • the accuracy of CPMVP can be 1/4 pixel accuracy
  • the bit depth of CPMVP can be 16 bits.
  • the accuracy of CPMVD can be 1/16 pixel accuracy, and the bit depth of CPMVD can be 16bit; or, the accuracy of CPMVD can be 1/4 pixel accuracy, and the bit depth of CPMVD can be It is 16bit; or, the precision of CPMVD can be the precision of whole pixels, and the bit depth of CPMVD can be 16bit.
  • the CPMV can be determined by improving the accuracy of CPMVP and CPMVD, thereby improving the accuracy of the inter prediction of the current affine coding block.
  • the following details how to determine CPMV by improving the accuracy of CPMVP and CPMVD.
  • the motion vector of the control point of the current affine coding block can be obtained according to the CPMVD and the first offset value.
  • the motion vector of the control point of the current affine coding block can be obtained according to the CPMVP and the second offset value.
  • the current affine coding block can be obtained according to CPMVD, the first offset value, CPMVP, and the second offset value Control point motion vector.
  • the following formula (12) may be used to obtain the motion vector of the control point of the current affine coding block.
  • CPMVD' CPMVD ⁇ mvrShift1.
  • CPMVD' CPMVD. Understandably, the accuracy of CPMVD does not need to be adjusted.
  • CPMVP' CPMVP ⁇ mvrShift2.
  • CPMVP' CPMVP. Understandably, the accuracy of CPMVP does not need to be adjusted.
  • CPMV represents the motion vector of the control point
  • mvrShift1 represents the first offset value
  • mvrShift2 represents the second offset value
  • the first offset value may be determined according to the accuracy of the first motion vector and the accuracy of CPMVD.
  • the accuracy of the first motion vector is 1/2 m and the accuracy of the CPMVD is 1/2 n
  • the first offset value may be the difference of m minus n
  • the second offset value may be determined according to the accuracy of the first motion vector and the accuracy of CPMVP.
  • the accuracy of the first motion vector is 1/2 m
  • the accuracy of CPMVP is 1/2 n
  • the second offset value may be the difference of m minus n.
  • the first offset value is equal to 0; when the first When a motion vector accuracy is 1/16 pixel accuracy and CPMVD accuracy is 1/4 (1/2 2 ) pixel accuracy, the first offset value is equal to 2; when the first motion vector accuracy is 1/16 pixel accuracy and CPMVD When the precision of is full pixel precision (1/2 0 ), the first offset value is equal to 4.
  • the second offset value is equal to 0; when the first motion vector accuracy is 1/16 pixel accuracy and CPMVP accuracy is 1 /4 pixel accuracy, the second offset value is equal to 2; when the first motion vector accuracy is 1/16 pixel accuracy and the CPMVP accuracy is integer pixel accuracy, the second offset value is equal to 4.
  • the motion vector of the control point of the current affine coding block may have the following values.
  • the value of the first offset value can be 0, and the value of the second offset value can be 2, the current affine encoding
  • the value of the first offset value can be 2
  • the value of the second offset value can be 2
  • the value of the first offset value can be 4
  • the value of the second offset value can be 2
  • the first offset value is equal to 1; when the first motion vector accuracy is 1/32 pixel accuracy and the CPMVD accuracy is 1/4 (1/2 2 ) pixel accuracy, the first offset value is equal to 3; when the first motion vector accuracy is 1 /32 pixel accuracy and CPMVD accuracy is integer pixel accuracy (1/2 0 ), the first offset value is equal to 5.
  • the second offset value is equal to 1; when the first motion vector accuracy is 1/32 pixel accuracy and CPMVP accuracy is 1 /4 pixel accuracy, the second offset value is equal to 3; when the first motion vector accuracy is 1/32 pixel accuracy and the CPMVP accuracy is integer pixel accuracy, the second offset value is equal to 5.
  • the motion vector of the control point of the current affine coding block may have the following values.
  • the value of the first offset value can be 1
  • the value of the second offset value can be 3
  • the value of the first offset value can be 3
  • the value of the second offset value can be 3
  • the value of the first offset value can be 5
  • the value of the second offset value can be 3
  • the first offset value is equal to 2; when the first motion vector accuracy is 1/64 pixel accuracy and the CPMVD accuracy is 1/4 (1/2 2 ) pixel accuracy, the first offset value is equal to 4; when the first motion vector accuracy is 1 /64 pixel precision and the precision of CPMVD is the whole pixel precision (1/2 0 ), the first offset value is equal to 6.
  • the second offset value is equal to 2; when the first motion vector accuracy is 1/64 pixel accuracy and CPMVP accuracy is 1 /4 pixel accuracy, the second offset value is equal to 4; when the first motion vector accuracy is 1/64 pixel accuracy and the CPMVP accuracy is integer pixel accuracy, the second offset value is equal to 6.
  • the motion vector of the control point of the current affine coding block may have the following values.
  • the value of the first offset value can be 2
  • the value of the second offset value can be 4
  • the value of the first offset value can be 4
  • the value of the second offset value can be 4
  • the value of the first offset value can be 6
  • the value of the second offset value can be 4
  • the motion vector of the control point can also be clamped so that the bit depth of the motion vector of the control point is equal to the bit depth of the first motion vector.
  • bit depth of the motion vector of the control point For example, comparing the bit depth of the motion vector of the control point with the bit depth of the first motion vector, when the bit depth of the motion vector of the control point is greater than the bit depth of the first motion vector, the motion vector of the control point is clamped to make the control point
  • the bit depth of the motion vector is equal to the bit depth of the first motion vector.
  • the following formula (13) may be used to clamp the motion vector of the control point so that the bit depth of the motion vector of the control point is equal to the bit depth of the first motion vector.
  • vx Clip3 (-2 bitDepth-1 , 2 bitDepth-1 -1, vx)
  • (vx, vy) is the motion vector of the control point of the current affine coding block
  • the definition of Clip3 is to indicate that the value of z is clamped to the interval [x, y]:
  • the bit depth of the first motion vector is 18 bits, and the range that the MV can represent is (-2 13 , 2 13 -1).
  • the bit depth of the motion vector of the control point can be clamped, that is, 18 bits are substituted into the formula (13) to make the control point
  • the bit depth of the motion vector is equal to the bit depth of the first motion vector.
  • S903 Derive the motion vector of each motion compensation unit in the current affine coding block according to the motion vector of the control point.
  • an affine transformation model is used to determine the motion information of each motion compensation unit in the current affine coding block.
  • the motion information of pixels at preset positions in the motion compensation unit may be used to represent the motion information of all pixels in the motion compensation unit.
  • the pixel position at the preset position may be the center point of the motion compensation unit (M/2,N/2), the upper left vertex (0,0), and the upper right vertex (M-1,0), Or pixels in other locations.
  • the following uses the center point of the motion compensation unit as an example.
  • the size of the motion compensation unit MxN is the size determined by the same rules commonly agreed by the codec, and can be fixedly set to 4x4, 8x8, etc., or can be determined according to the difference of the motion vector of the control point, the accuracy of the motion vector, and the distance between the control points .
  • the size of the current motion compensation unit of the affine coding block can be determined by other methods, and will not be described in detail in this application.
  • the coordinates of the center point of the motion compensation unit relative to the upper left vertex pixel of the current affine coding block can be calculated using formula (14).
  • (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 vertex pixel of the current affine coding block. Substitute (x (i,j) ,y (i,j) ) into formula (15) to obtain the motion information of the center point of each motion compensation unit as the motion information of all pixels in the motion compensation unit (vx ( i,j) ,vy (i,j) ).
  • the motion-compensated motion vector can be calculated according to the following formula:
  • mvShift when the accuracy of CPMV is 1/4 pixel accuracy, mvShift can be set to 5, and the accuracy of the motion vector of the motion compensation unit is 1/16 pixel accuracy.
  • the precision of CPMV is 1/16 pixel precision, mvShift can be set to 7, and the precision of the motion vector of the motion compensation unit is 1/16 pixel precision.
  • the accuracy of CPMV is 1/16 pixel accuracy, mvShift can be set to 9, and the accuracy of the motion vector of the motion compensation unit is 1/4 pixel accuracy.
  • the bit depth of the motion vector of the motion compensation unit is 18 bits.
  • each motion compensation unit For example, based on the motion vector of each motion compensation unit, perform motion compensation to obtain the prediction block of the current affine coding block, and for each motion compensation unit of the current affine coding block, use the motion information obtained in S903 to perform motion Compensation prediction, get the prediction value of each motion compensation unit. Then, based on the prediction block and the motion vector of each motion compensation unit, a reconstructed block of the current affine coding block is obtained.
  • the prediction block and the residual block of the current affine coding block to obtain the reconstructed block of the current affine coding block; or, update the prediction block according to the motion vector of each motion compensation unit, and update Add the prediction block and the residual block of the current affine coding block to obtain the reconstructed block of the current affine coding block; or, add the prediction block and the residual block of the current affine coding block to obtain the current affine coding
  • the reconstruction block of the block filtering the reconstruction block based on the motion vector of each motion compensation unit; or, adding the prediction block and the residual block of the current affine coding block to obtain the reconstruction block of the current affine coding block,
  • the motion vector and the reconstructed block of each motion compensation unit are used as prediction information of the subsequent current affine coding block.
  • S905 may not be performed.
  • the size of the motion information storage unit is 4x4.
  • the motion information is set as the motion information of the motion compensation unit.
  • the motion vector of the motion compensation unit needs to be quantized to the motion vector accuracy of the storage unit for storage. Examples are as follows:
  • MCUMV’ (MCUMV>>mvrShift3) (16)
  • MCUMV' represents the motion vector of the motion compensation unit after processing
  • MCUMV represents the motion vector of the motion compensation unit before processing
  • mvrShift3 represents the third offset value.
  • the third offset value may be determined according to the accuracy of the second motion vector and the accuracy of MCUMV.
  • the accuracy of the second motion vector is 1/2 k
  • the accuracy of MCUMV is 1/2 n
  • the third offset value may be the difference of n minus k.
  • the third offset is equal to 2
  • the motion vector accuracy of the processed motion compensation unit can be derived directly from formula (15) to meet the second motion vector accuracy; the motion vector accuracy of the motion compensation unit obtained in S903 can also be directly quantified, so that The motion vector of the processed motion compensation unit satisfies the accuracy of the second motion vector.
  • the quantization method is the round function in S903.
  • the motion vector accuracy of the motion compensation unit is 1/16 pixel accuracy.
  • the motion of the processed motion compensation unit Vector accuracy is 1/4 pixel accuracy, mvShift can be set to 2.
  • bit depth of the motion vector of the processed motion compensation unit may be clamped so that the bit depth of the motion vector of the processed motion compensation unit is equal to the bit depth of the second motion vector.
  • the motion vector of the processed motion compensation unit is clamped to make the bit of the motion vector of the processed motion compensation unit
  • the depth is equal to the second motion vector bit depth.
  • the range that MV can represent is (-2 11 , 2 11 -1).
  • the bit depth of the motion vector of the processed motion compensation unit can be clamped, that is, 16 bits are substituted into the formula ( 13), so that the bit depth of the motion vector of the processed motion compensation unit is equal to the bit depth of the second motion vector.
  • the second motion vector accuracy may be the motion vector accuracy of the storage unit.
  • the accuracy of the above CPMVP may be the same as the accuracy of the motion vector of the storage unit.
  • the second motion vector bit depth may be the motion vector bit depth of the storage unit.
  • the bit depth of CPMVP may be the same as the bit depth of the storage unit.
  • the sequence of the steps of the inter prediction method provided in the embodiments of the present application can be adjusted appropriately, and the steps can also be increased or decreased according to the situation.
  • S904 can be combined with S905 and S906.
  • Interchangeable that is, the motion vector accuracy of the motion compensation unit can be processed first to meet the preset second motion vector accuracy, and/or, the motion vector bit depth of the motion compensation unit can be processed to meet the preset second motion vector accuracy bit Depth, and store the motion vector of the processed motion compensation unit, and then based on the motion vector of each motion compensation unit, obtain the reconstruction block of the current affine coding block.
  • Embodiment 1 of the present application proposes an accuracy change process in the affine AMVP mode. By improving the accuracy and bit depth of the motion vector of the control point and performing motion compensation, the frame of the coding block using the affine motion model can be effectively improved Prediction accuracy.
  • FIG. 10 is a flowchart of an inter prediction method according to an embodiment of the present application. Assuming that the image block to be processed is the current affine coding block, as shown in FIG. 10, the method may include:
  • the method for determining the inter prediction mode of the current affine coding block can be obtained by parsing the syntax elements, and the specific determination method is not specifically limited in this application. If it is determined that the inter prediction mode of the current affine coding block is the Merge mode based on the affine motion model, the following steps are performed.
  • the method for obtaining the motion information of the control points of the current affine coding block can be referred to the description of obtaining the motion information of the control points of the current affine coding block described in the aforementioned “Affine Fusion Mode (Affine Merge mode)”, which will not be repeated here. .
  • the motion vector of the control point can be obtained by the inherited motion vector prediction method or the constructive motion vector prediction method, then the precision of the motion vector of the control point and the bit depth of the motion vector of the control point can be based on the phase of the current affine coding block Adjacent affine units are obtained.
  • the motion vector accuracy and bit depth of adjacent blocks can be obtained by reading the motion information of the storage unit.
  • the motion information of the storage unit is stored with low precision.
  • the accuracy of the motion vector of the storage unit is 1/4 pixel accuracy
  • the bit depth of the motion vector of the storage unit is 16 bits.
  • the precision of the motion vector of the control point is 1/4 pixel precision
  • the bit depth of the motion vector of the control point is 16bit.
  • the accuracy of the inter-frame prediction of the current affine coding block is low. Therefore, the accuracy of the inter-frame prediction of the current affine coding block can be improved by improving the accuracy of CPMV.
  • the following details how to improve the accuracy of CPMV.
  • the control can be adjusted according to the motion vector of the control point and the first offset value
  • the motion vector of the point, the motion vector of the adjusted control point is obtained, so that the motion vector of the adjusted control point satisfies the first motion vector accuracy.
  • CPMV’ CPMV ⁇ mvrShift1 (17)
  • CPMV represents the motion vector of the control point
  • CPMV' represents the motion vector of the adjusted control point
  • mvrShift1 represents the first offset value
  • the first offset value may be determined according to the accuracy of the first motion vector and the accuracy of CPMV.
  • the accuracy of the first motion vector is 1/2 m and the accuracy of the CPMV is 1/2 n
  • the first offset value may be the difference between m and n.
  • the first offset value when the first motion vector accuracy is 1/16 (1/2 4 ) pixel accuracy and the control point motion vector accuracy is 1/16 pixel accuracy, the first offset value is equal to 0; when the first motion vector accuracy is 1/16 pixel accuracy and the control point motion vector accuracy is 1/4 (1/2 2 ) pixel accuracy, the first offset value is equal to 2; when the first motion vector accuracy When the precision of the 1/16 pixel precision and the precision of the motion vector of the control point is the full pixel precision (1/2 0 ), the first offset value is equal to 4.
  • the motion vector of the adjusted control point of the current affine coding block may have the following values.
  • the value of the first offset value may be 2
  • the first offset value is equal to 1; when the first motion vector accuracy is 1/32 pixel accuracy and the control point motion vector accuracy is 1/4 (1/2 2 ) pixel accuracy, the first offset value is equal to 3; When the first motion vector accuracy is 1/32 pixel accuracy and the control point motion vector accuracy is whole pixel accuracy (1/2 0 ), the first offset value is equal to 5.
  • the motion vector of the adjusted control point of the current affine coding block may have the following values.
  • the first offset value is equal to 2; when the first motion vector accuracy is 1/64 pixel accuracy and the control point motion vector accuracy is 1/4 (1/2 2 ) pixel accuracy, the first offset value is equal to 4; When the first motion vector accuracy is 1/64 pixel accuracy and the control point motion vector accuracy is integer pixel accuracy (1/2 0 ), the first offset value is equal to 6.
  • the motion vector of the adjusted control point of the current affine coding block may have the following values.
  • the value of the first offset value may be 2
  • Method 2 If the motion vector of the control point is obtained by the inherited motion vector prediction method, that is, the prediction mode of the processed adjacent image block of the image block to be processed is the prediction mode based on the affine motion model, when the image block to be processed The motion vector of the control point is derived based on the motion vector of the control point of the processed adjacent image block, and the motion vector of the adjusted control point is obtained by the following formula:
  • K1 mvScaleHor+dHorX*(x0–x4–M/2)+dHorY*(y0–y4–N/2),
  • K6 mvScaleVer+dVerX*(x2–x4–M/2)+dVerY*(y2–y4–N/2),
  • Log2() represents the function of taking the logarithm of 2
  • ⁇ represents left shift
  • >> represents right shift
  • P is the width of the processed adjacent image block
  • Q is the height of the processed adjacent image block
  • (vx0,vy0), (vx1,vy1) and (vx2,vy2) represent the horizontal and vertical components of the motion vectors of the three control points of the image block to be processed, that is, (vx0,vy0) is the image to be processed
  • the horizontal and vertical components of the motion vector of the first control point of the block, (vx1,vy1) are the horizontal and vertical components of the motion vector of the second control point of the image block to be processed, (vx2,vy2) Are the horizontal and vertical components of the motion vector of the third control point of the image block to be processed,
  • (vx4, vy4), (vx5, vy5), and (vx6, vy6) represent the horizontal and vertical components of the motion vectors of the three control points of the adjacent image blocks, that is, (vx4, vy4) is already Process the horizontal and vertical components of the motion vector of the first control point of the adjacent image block, (vx5,vy5) is the horizontal and vertical components of the motion vector of the second control point of the processed adjacent image block , (Vx6, vy6) is the horizontal and vertical components of the motion vector of the third control point of the adjacent image block,
  • mvShift is determined based on the motion vector accuracy of the control points of the neighboring image blocks that have been processed.
  • adjacent image blocks may refer to spatially adjacent affine coding blocks or temporally adjacent affine coding blocks.
  • the accuracy of the CPMV stored in the adjacent affine block is 1/4 pixel accuracy
  • the accuracy of the CPMV of the image block to be processed is 1/16 pixel accuracy.
  • the accuracy of the CPMV stored in the adjacent affine block is 1/4 pixel accuracy
  • mvShift can be set to 6
  • the accuracy of the CPMV of the image block to be processed is 1/32 pixel accuracy.
  • the accuracy of the CPMV stored in the adjacent affine block is 1/4 pixel accuracy
  • mvShift can be set to 7 and the accuracy of the CPMV of the image block to be processed is 1/4 pixel accuracy.
  • the accuracy of the CPMV of the adjacent affine block may refer to the accuracy of the stored motion vector of the storage unit.
  • the motion vector of the control point can be adjusted by way two, that is, by setting mvShift, the motion vector of the control point meets the preset first motion vector accuracy. If the method 2 still fails to make the motion vector of the control point meet the preset first motion vector accuracy, the motion vector of the control point can be adjusted through the method 1 so that the motion vector of the control point meets the preset first motion vector accuracy. Of course, the motion vector of the control point can also be adjusted directly in mode 1, so that the motion vector of the control point meets the preset first motion vector accuracy.
  • the embodiments of the present application are not limited.
  • the motion vector of the adjusted control point may also be clamped so that the bit depth of the adjusted motion vector of the control point is equal to the bit depth of the first motion vector.
  • the bit depth of the first motion vector is 18 bits
  • the range that the MV can represent is (-2 13 , 2 13 -1).
  • the bit depth of the adjusted control point's motion vector can be clamped, ie, 18 bits are substituted into the formula (13) , So that the bit depth of the motion vector of the adjusted control point is equal to the bit depth of the first motion vector.
  • S1004 Derive the motion vector of each motion compensation unit in the current affine coding block according to the adjusted motion vector of the control point.
  • an affine transformation model is used to determine the motion information of each motion compensation unit in the current affine coding block.
  • the motion information of pixels at preset positions in the motion compensation unit may be used to represent the motion information of all pixels in the motion compensation unit.
  • the pixel position at the preset position may be the center point of the motion compensation unit (M/2,N/2), the upper left vertex (0,0), and the upper right vertex (M-1,0), Or pixels in other locations.
  • the following uses the center point of the motion compensation unit as an example.
  • the size of the motion compensation unit MxN is the size determined by the same rules commonly agreed by the codec, and can be fixedly set to 4x4, 8x8, etc., or can be determined according to the difference of the motion vector of the control point, the accuracy of the motion vector, and the distance between the control points .
  • the size of the current motion compensation unit of the affine coding block can be determined by other methods, and will not be described in detail in this application.
  • the coordinates of the center point of the motion compensation unit relative to the upper left vertex pixel of the current affine coding block can be calculated using formula (14).
  • (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 vertex pixel of the current affine coding block. Substitute (x (i,j) ,y (i,j) ) into formula (15) to obtain the motion information of the center point of each motion compensation unit as the motion information of all pixels in the motion compensation unit (vx ( ij) ,vy (ij) ).
  • the motion compensation unit's motion vector accuracy is 1/16 pixel accuracy
  • motion compensation The bit depth of the unit's motion vector is 18 bits.
  • the motion-compensated motion vector can be calculated according to the following formula:
  • mvShift when the accuracy of the motion vector of the adjusted control point is 1/16 pixel accuracy, mvShift can be set to 7, and the accuracy of the motion vector of the motion compensation unit is 1/16 pixel accuracy.
  • the precision of the adjusted motion vector of the control point is 1/16 pixel precision, mvShift can be set to 7, and the precision of the motion vector of the motion compensation unit is 1/16 pixel precision.
  • the precision of the adjusted motion vector of the control point is 1/16 pixel precision
  • mvShift can be set to 9 and the precision of the motion vector of the motion compensation unit is 1/4 pixel precision.
  • each motion compensation unit For example, based on the motion vector of each motion compensation unit, perform motion compensation to obtain the prediction block of the current affine coding block, and for each motion compensation unit of the current affine coding block, use the motion information obtained in S1003 to perform motion Compensation prediction, get the prediction value of each motion compensation unit. Then, based on the prediction block and the motion vector of each motion compensation unit, a reconstructed block of the current affine coding block is obtained.
  • the prediction block and the residual block of the current affine coding block to obtain the reconstructed block of the current affine coding block; or, update the prediction block according to the motion vector of each motion compensation unit, and update Add the prediction block and the residual block of the current affine coding block to obtain the reconstructed block of the current affine coding block; or, add the prediction block and the residual block of the current affine coding block to obtain the current affine coding
  • the reconstruction block of the block filtering the reconstruction block based on the motion vector of each motion compensation unit; or, adding the prediction block and the residual block of the current affine coding block to obtain the reconstruction block of the current affine coding block,
  • the motion vector and the reconstructed block of each motion compensation unit are used as prediction information of the subsequent current affine coding block.
  • S1006 may not be performed.
  • the size of the motion information storage unit is 4x4.
  • the motion information is set as the motion information of the motion compensation unit.
  • the motion vector of the motion compensation unit needs to be quantized to the motion vector accuracy of the storage unit for storage. Examples are as follows:
  • MCUMV’ (MCUMV>>mvrShift2) (18)
  • MCUMV' represents the motion vector of the motion compensation unit after processing
  • MCUMV represents the motion vector of the motion compensation unit before processing
  • mvrShift2 represents the second offset value
  • the second offset value may be determined according to the accuracy of the second motion vector and the accuracy of MCUMV.
  • the accuracy of the second motion vector is 1/2 k
  • the accuracy of MCUMV is 1/2 n
  • the second offset value may be the difference of n minus k.
  • the second offset is equal to 2
  • bit depth of the motion vector of the processed motion compensation unit may be clamped so that the bit depth of the motion vector of the processed motion compensation unit is equal to the bit depth of the second motion vector.
  • the motion vector of the processed motion compensation unit is clamped to make the bit of the motion vector of the processed motion compensation unit
  • the depth is equal to the second motion vector bit depth.
  • the range that MV can represent is (-2 11 , 2 11 -1).
  • the bit depth of the motion vector of the processed motion compensation unit can be clamped, that is, 16 bits are substituted into the formula ( 13), so that the bit depth of the motion vector of the processed motion compensation unit is equal to the bit depth of the second motion vector.
  • the sequence of the steps of the inter prediction method provided in the embodiments of the present application can be adjusted appropriately, and the steps can also be increased or decreased according to the situation.
  • the sequence between S1005 and S1006 and S1007 can be Interchange, that is, first process the motion vector accuracy of the motion compensation unit to meet the preset second motion vector accuracy, and/or, process the motion compensation unit motion vector bit depth to meet the preset second motion vector accuracy bit depth, And store the motion vector of the processed motion compensation unit, and then obtain the reconstruction block of the current affine coding block based on the motion vector of each motion compensation unit.
  • Interchange that is, first process the motion vector accuracy of the motion compensation unit to meet the preset second motion vector accuracy, and/or, process the motion compensation unit motion vector bit depth to meet the preset second motion vector accuracy bit depth, And store the motion vector of the processed motion compensation unit, and then obtain the reconstruction block of the current affine coding block based on the motion vector of each motion compensation unit.
  • Embodiment 1 of the present application proposes an accuracy change process in the affine AMVP mode. By improving the accuracy and bit depth of the motion vector of the control point and performing motion compensation, the frame of the coding block using the affine motion model can be effectively improved Prediction accuracy.
  • An embodiment of the present application provides an apparatus for inter prediction.
  • the apparatus may be a video decoder, a video encoder, or a decoder.
  • the inter prediction device is used to perform the steps performed by the decoding device in the above inter prediction method.
  • the apparatus for inter prediction provided in the embodiments of the present application may include modules corresponding to corresponding steps.
  • the embodiments of the present application may divide the function module of the inter prediction device according to the above method example.
  • each function module may be divided corresponding to each function, or two or more functions may be integrated into one processing module.
  • the above integrated modules can be implemented in the form of hardware or software function modules.
  • the division of the modules in the embodiments of the present application is schematic, and is only a division of logical functions. In actual implementation, there may be another division manner.
  • FIG. 11 shows a possible structural schematic diagram of the apparatus for inter prediction involved in the foregoing embodiment.
  • the apparatus 1100 for inter prediction may include a determination module 1101, an acquisition module 1102, a calculation module 1103, and a reconstruction module 1104.
  • the functions of each module are as follows:
  • the determining module 1101 is used to determine that the prediction mode of the image block to be processed is an AMVP mode based on an affine motion model.
  • the obtaining module 1102 is configured to obtain a motion vector of a control point of an image block to be processed, and the motion vector of the control point satisfies a preset first motion vector accuracy and/or a first motion vector bit depth.
  • the calculation module 1103 is used to derive the motion vector of each motion compensation unit in the image block to be processed according to the motion vector of the control point.
  • the reconstruction module 1104 is configured to obtain a reconstruction block of the image block to be processed based on the motion vector of each motion compensation unit.
  • the determining module 1101 is used to support the inter prediction device 1100 to perform S901 or S1001 in the above embodiments, and/or other processes used in the technology described herein.
  • the obtaining module 1102 is used to support the inter-frame prediction device 1100 to perform S902 or S1002 in the above embodiments, and/or other processes used in the technology described herein.
  • the calculation module 1103 is used to support the inter-frame prediction device 1100 to perform S903 and S905 or S1004 in the above-mentioned embodiments, and/or other processes for the technology described herein.
  • the reconstruction module 1104 is used to support the inter-frame prediction device 1100 to perform S904 or S1005 in the above embodiments, and/or other processes used in the technology described herein.
  • the apparatus 1100 for inter prediction may further include an adjustment module 1105, which is used to adjust the motion vector of the control point to meet the preset first motion vector accuracy and/or the first motion vector bit depth.
  • the adjustment module 1105 is used to support the inter-frame prediction device 1100 to perform S1003 and S1006 in the foregoing embodiments, and/or other processes used in the technology described herein.
  • the apparatus 1100 for inter prediction may further include a storage module 1106 for storing the motion vector of the processed motion compensation unit.
  • the storage module 1106 is used to support the inter-frame prediction device 1100 to perform S906 and S1007 in the foregoing embodiments, and/or other processes used in the technology described herein.
  • FIG. 12 is a schematic structural block diagram of an apparatus 1200 for inter prediction in an embodiment of the present application.
  • the apparatus 1200 for inter prediction includes: a processing module 1201 and a storage module 1202 coupled to the processing module; the processing module 1201 is used to execute the embodiment shown in FIG. 11 and various feasible implementation manners.
  • the processing module 1201 may be a processor or a controller, such as a central processing unit (CPU), a general-purpose processor, a digital signal processor (Digital Signal Processor, DSP), ASIC, FPGA, or other programmable Logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute various exemplary logical blocks, modules, and circuits described in conjunction with the disclosure of the present application.
  • the processor may also be a combination of computing functions, for example, including one or more microprocessor combinations, a combination of DSP and microprocessor, and so on.
  • the storage module 1202 may be a memory.
  • Both the above-mentioned inter-frame prediction device 1100 and the inter-frame prediction device 1200 can perform the above-described inter-frame prediction method shown in FIG. 9 or FIG. 10.
  • the inter-frame prediction device 1100 and the inter-frame prediction device 1200 may specifically be video decoding Device or other equipment with video codec function.
  • the apparatus 1100 for inter prediction and the apparatus 1200 for inter prediction may be used to perform image prediction in the decoding process.
  • An embodiment of the present application provides an inter prediction device.
  • the inter prediction device may be a video decoder, a video encoder, or a decoder. Specifically, the inter prediction device is used to perform the steps performed by the inter prediction device in the above inter prediction method.
  • the inter prediction apparatus provided in the embodiments of the present application may include modules corresponding to corresponding steps.
  • the inter prediction device may be divided into function modules according to the above method example.
  • each function module may be divided corresponding to each function, or two or more functions may be integrated into one processing module.
  • the above integrated modules can be implemented in the form of hardware or software function modules.
  • the division of the modules in the embodiments of the present application is schematic, and is only a division of logical functions. In actual implementation, there may be another division manner.
  • the present application also provides a terminal, which includes: one or more processors, a memory, and a communication interface.
  • the memory and the communication interface are coupled to one or more processors; the memory is used to store computer program code, and the computer program code includes instructions.
  • the terminal performs the inter-frame prediction of the embodiment of the present application. method.
  • the terminal here can be a video display device, a smart phone, a portable computer, and other devices that can process video or play video.
  • the present application also provides a video decoder, including a non-volatile storage medium, and a central processor, the non-volatile storage medium stores an executable program, the central processor and the non-volatile storage Connect the media and execute the executable program to implement the method of inter prediction in the embodiments of the present application.
  • the present application also provides a decoder including the apparatus for inter prediction in the embodiments of the present application.
  • Another embodiment of the present application further provides a computer-readable storage medium, the computer-readable storage medium includes one or more program codes, the one or more programs include instructions, and when the processor in the terminal is executing the program code At this time, the terminal performs the method of inter prediction as shown in FIG. 9 or FIG. 10.
  • a computer program product in another embodiment, includes computer-executable instructions, and the computer-executable instructions are stored in a computer-readable storage medium; at least one processor of the terminal may be accessible from the computer.
  • the read storage medium reads the computer-executed instruction, and at least one processor executes the computer-executed instruction to cause the terminal to implement the method for performing inter prediction as shown in FIG. 9 or FIG. 10.
  • the computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable devices.
  • the computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be from a website site, computer, server or data center Transmission to another website, computer, server or data center via wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.).
  • the computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device including a server, a data center, and the like integrated with one or more available media.
  • the available media may be magnetic media (eg, floppy disk, hard disk, magnetic tape), optical media (eg, DVD), or semiconductor media (eg, Solid State Disk (SSD)), or the like.
  • actions or events of any of the methods described herein may be performed in different sequences, may be added, merged, or omitted together (eg, not all described Actions or events are necessary for the practice method).
  • actions or events may be performed simultaneously rather than sequentially, for example, via multi-threaded processing, interrupt processing, or multiple processors.
  • specific aspects of the present application are described as being performed by a single module or unit for clarity, it should be understood that the technology of the present application can be performed by a combination of units or modules associated with a video decoder.
  • the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit.
  • the computer-readable medium may include a computer-readable storage medium or a communication medium, the computer-readable storage medium corresponding to a tangible medium such as a data storage medium, and the communication medium includes facilitating the transfer of a computer program (for example) from one place to another according to a communication protocol Any media.
  • computer-readable media may illustratively correspond to (1) non-transitory tangible computer-readable storage media, or (2) communication media such as signals or carrier waves.
  • Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and/or data structures for implementation of the techniques described in this application.
  • the computer program product may include a computer-readable medium.
  • this computer-readable storage medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage devices, magnetic disk storage devices or other magnetic storage devices, flash memory, or may be used to store instructions Or any other medium that can be accessed by a computer in the form of a desired code in the form of a data structure. Also, any connection is properly termed a computer-readable medium.
  • coaxial cable fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technology such as infrared, radio, and microwave
  • DSL digital subscriber line
  • coaxial Cables, fiber optic cables, twisted pairs, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of media.
  • computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other temporary media, but are instead directed to non-transitory tangible storage media.
  • magnetic disks and optical discs include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), flexible magnetic discs, and Blu-ray discs, where magnetic discs usually reproduce data magnetically, while optical discs use The data is reproduced optically. Combinations of the above should also be included within the scope of computer-readable media.
  • DSPs digital signal processors
  • ASICs application specific integrated circuits
  • FPGAs field programmable gate arrays
  • processors may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein.
  • functionality described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or incorporated in a combined codec.
  • the technology can be fully implemented in one or more circuits or logic elements.
  • the technology of the present application can be implemented in a wide variety of devices or equipment, including wireless handsets, integrated circuits (ICs), or collections of ICs (eg, chipsets).
  • ICs integrated circuits
  • collections of ICs eg, chipsets.
  • Various components, modules, or units are described in this application to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily need to be implemented by different hardware units. Rather, as described above, various units may be combined in a codec hardware unit or by interoperable hardware units (including one or more processors as described above) in combination with suitable software and/or firmware To provide.

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Abstract

一种帧间预测的方法，包括：在待处理图像块的预测模式为基于仿射运动模型的先进运动矢量预测模式的情况下（S901），获得待处理图像块的控制点的运动矢量（S902），其中，控制点的运动矢量满足预设的第一运动矢量精度和/或第一运动矢量比特深度；然后，根据控制点的运动矢量，推导待处理图像块中每个运动补偿单元的运动矢量（S903）；基于每个运动补偿单元的运动矢量，获取待处理图像块的重建块（S904）。

Description

一种帧间预测的方法和装置
本申请要求于2018年12月24日提交国家知识产权局、申请号为201811588243.6、申请名称为“一种帧间预测的方法和装置”的中国专利申请的优先权，本申请还要求于2019年02月02日提交国家知识产权局、申请号为201910108004.4、申请名称为“一种帧间预测的方法和装置”的中国专利申请的优先权，这些全部内容通过引用结合在本申请中。
技术领域
本申请实施例涉及视频编解码领域，尤其涉及一种帧间预测的方法和装置。
背景技术
随着信息技术的发展，高清晰度电视，网络会议，IPTV，3D电视等视频业务迅速发展，视频信号以其直观性和高效性等优势成为人们日常生活中获取信息最主要的方式。由于视频信号包含的数据量大，需要占用大量的传输带宽和存储空间。为了有效地传输和存储视频信号，需要对视频信号进行压缩编码，视频压缩技术越来越成为视频应用领域不可或缺的关键技术。在编解码过程中，为了节省存储空间，通常以较低的精度存储与运动信息。但是，如果仍然以较低精度的运动信息进行编码或解码，造成帧间预测的准确率较低。
发明内容
本申请实施例提供一种帧间预测的方法和装置，能够有效地提高帧间预测的准确率。
第一方面，本申请实施例提供了一种帧间预测的方法，包括：确定待处理图像块的预测模式为基于仿射运动模型的预测模式；获得所述待处理图像块的控制点的运动矢量；根据所述控制点的运动矢量，推导所述待处理图像块中每个运动补偿单元的运动矢量；基于所述每个运动补偿单元的运动矢量，分别进行运动补偿，以获得所述待处理图像块的预测块；处理所述运动补偿单元的运动矢量以满足预设的运动矢量精度和/或运动矢量比特深度；基于所述预测块和所述处理后的运动矢量，获得所述待处理图像块的重建块。
在一种可行的实施方式中，所述处理所述运动补偿单元的运动矢量以满足预设的运动矢量精度和/或运动矢量比特深度，包括：比较所述运动补偿单元的运动矢量精度和/或运动矢量比特深度，和所述预设的运动矢量精度和/或运动矢量比特深度；当所述运动补偿单元的运动矢量不满足预设的运动矢量精度和/或运动矢量比特深度时，将所述运动补偿单元的运动矢量精度和/或运动矢量比特深度转化为所述预设的运动矢量精度和/或运动矢量比特深度。
在一种可行的实施方式中，将所述运动补偿单元的运动矢量精度和/或运动矢量比特深度转化为所述预设的运动矢量精度和/或运动矢量比特深度，包括：
如果存储单元的运动矢量精度和比特深度为1/4、16bit，运动补偿单元的运动矢量 的精度和比特深度为1/16、18bit，则最终运动补偿单元的运动信息存储的精度和比特深度为1/4、16bit。可以直接通过说明书中的公式(9)推导得到1/4精度的运动矢量进行存储；也可以直接将步骤根据所述控制点的运动矢量，推导所述待处理图像块中每个运动补偿单元的运动矢量中得到的1/16精度的运动矢量进行量化，得到1/4精度的运动矢量，量化的方法如下文中的round函数，其中mvShift设置为2。
在一种可行的实施方式中，还包括：当所述运动补偿单元的运动矢量满足预设的运动矢量精度和/或运动矢量比特深度时，不进行所述转化。
在一种可行的实施方式中，所述基于所述预测块和所述处理后的运动矢量，获得所述待处理图像块的重建块，包括：将所述预测块和所述待处理图像块的残差块相加，获得所述待处理图像块的重建块；或者，根据所述处理后的运动矢量，对所述预测块进行更新，将所述更新后的预测块和所述待处理图像块的残差块相加，获得所述待处理图像块的重建块；或者，将所述预测块和所述待处理图像块的残差块相加，获得所述待处理图像块的重建块，基于所述处理后的运动矢量，对所述重建块进行滤波处理；或者，将所述预测块和所述待处理图像块的残差块相加，获得所述待处理图像块的重建块，将所述处理后的运动矢量和所述重建块作为后续待处理图像块的预测信息。
第二方面，本申请实施例提供了一种帧间预测的方法，包括：确定待处理图像块的预测模式为基于仿射运动模型的预测模式；获得所述待处理图像块的控制点的运动矢量；处理所述控制点的运动矢量以满足预设的运动矢量精度和/或运动矢量比特深度；根据所述处理后的运动矢量，推导所述待处理图像块中每个运动补偿单元的运动矢量；基于所述每个运动补偿单元的运动矢量，分别进行运动补偿，以获得所述待处理图像块的预测块。
在一种可行的实施方式中，所述处理所述控制点的运动矢量以满足预设的运动矢量精度和/或运动矢量比特深度，包括：比较所述控制点的运动矢量精度和/或运动矢量比特深度，和所述预设的运动矢量精度和/或运动矢量比特深度；当所述控制点的运动矢量不满足预设的运动矢量精度和/或运动矢量比特深度时，将所述控制点的运动矢量的精度和/或运动矢量比特深度转化为所述预设的运动矢量精度和/或运动矢量比特深度。
在一种可行的实施方式中，所述将所述控制点的运动矢量精度和/或运动矢量比特深度转化为所述预设的运动矢量精度和/或运动矢量比特深度，包括：
如果CPMV是通过继承性的运动矢量预测方法得到，则CPMV的精度和比特深度可以根据当前块的相邻仿射单元得到，其中，相邻块的运动矢量精度和比特深度通过读取存储单元的运动信息得到，即为1/4精度、16bit。通过说明书中公式(6)、(7)的公式推导得到1/16精度的运动矢量。
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，P为相邻仿射编码块的宽度、Q为相邻仿射编码块的高度：
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和mvShift，其输出K通过以下方式获得：
offset＝1<<(mvShift–1)
K＝K>＝0？(K+offset)>>mvShift:–((–K+offset)>>mvShift)
通过将mvShift设置为5，达到CPMV精度提升的目的。
接着对得到的CPMV进行钳位，使得其不超过18bit的动态范围。
如果CPMV是通过构造型的运动矢量预测方法得到，则CPMVP的精度和存储与相邻块的一样，即为1/4精度、16bit。再通过左移2位，得到1/4精度、18bit的CPMV。
在一种可行的实施方式中，还包括：当所述控制点的运动矢量满足预设的运动矢量精度和/或运动矢量比特深度时，不进行所述转化。
第三方面，本申请实施例提供了一种帧间预测的装置，包括：确定模块，用于确定待处理图像块的预测模式为基于仿射运动模型的预测模式；获取模块，用于获得所述待处理图像块的控制点的运动矢量；计算模块，用于根据所述控制点的运动矢量，推导所述待处理图像块中每个运动补偿单元的运动矢量；补偿模块，用于基于所述每个运动补偿单元的运动矢量，分别进行运动补偿，以获得所述待处理图像块的预测块；处理模块，用于处理所述运动补偿单元的运动矢量以满足预设的运动矢量精度和/或运动矢量比特深度；重建模块，用于基于所述预测块和所述处理后的运动矢量，获得所述待处理图像块的重建块。
在一种可行的实施方式中，所述处理模块具体用于：比较所述运动补偿单元的运动矢量精度和/或运动矢量比特深度，和所述预设的运动矢量精度和/或运动矢量比特深度；当所述运动补偿单元的运动矢量不满足预设的运动矢量精度和/或运动矢量比特深度时，将所述运动补偿单元的运动矢量精度和/或运动矢量比特深度转化为所述预设的运动矢量精度和/或运动矢量比特深度。
在一种可行的实施方式中，所述处理模块还用于：当所述运动补偿单元的运动矢 量满足预设的运动矢量精度和/或运动矢量比特深度时，不进行所述转化。
在一种可行的实施方式中，所述重建模块具体用于：将所述预测块和所述待处理图像块的残差块相加，获得所述待处理图像块的重建块；或者，根据所述处理后的运动矢量，对所述预测块进行更新，将所述更新后的预测块和所述待处理图像块的残差块相加，获得所述待处理图像块的重建块；或者，将所述预测块和所述待处理图像块的残差块相加，获得所述待处理图像块的重建块，基于所述处理后的运动矢量，对所述重建块进行滤波处理；或者，将所述预测块和所述待处理图像块的残差块相加，获得所述待处理图像块的重建块，将所述处理后的运动矢量和所述重建块作为后续待处理图像块的预测信息。
第四方面，本申请实施例提供了一种帧间预测的装置，包括：确定模块，用于确定待处理图像块的预测模式为基于仿射运动模型的预测模式；获取模块，用于获得所述待处理图像块的控制点的运动矢量；处理模块，用于处理所述控制点的运动矢量以满足预设的运动矢量精度和/或运动矢量比特深度；计算模块，用于根据所述处理后的运动矢量，推导所述待处理图像块中每个运动补偿单元的运动矢量；补偿模块，用于基于所述每个运动补偿单元的运动矢量，分别进行运动补偿，以获得所述待处理图像块的预测块。
在一种可行的实施方式中，所述处理模块具体用于：比较所述控制点的运动矢量精度和/或运动矢量比特深度，和所述预设的运动矢量精度和/或运动矢量比特深度；当所述控制点的运动矢量不满足预设的运动矢量精度和/或运动矢量比特深度时，将所述控制点的运动矢量精度和/或运动矢量比特深度转化为所述预设的运动矢量精度和/或运动矢量比特深度。
在一种可行的实施方式中，所述处理模块还用于：当所述控制点的运动矢量满足预设的运动矢量精度和/或运动矢量比特深度时，不进行所述转化。
第五方面，本申请实施例提供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上述任一方面所述的方法。
相比于现有技术中需要分别推导存储的运动信息和运动补偿的运动信息，本申请通过提高控制点的运动矢量的精度和比特深度，进行运动补偿，可以有效地提高使用仿射运动模型的编码块的帧间预测准确率。
另外，上述任意方面的设计方式所带来的技术效果可参见第一方面和第二方面中不同设计方式所带来的技术效果，此处不再赘述。
本申请实施例中，帧间预测装置的名字对设备本身不构成限定，在实际实现中，这些设备可以以其他名称出现。只要各个设备的功能和本申请实施例类似，属于本申请权利要求及其等同技术的范围之内。
第六方面，本申请实施例提供了一种帧间预测的方法，包括：在确定待处理图像块的预测模式为基于仿射运动模型的先进运动矢量(Advanced Motion Vector Prediction，AMVP)模式之后，获得待处理图像块的控制点的运动矢量，然后，根据控制点的运动矢量，推导待处理图像块中每个运动补偿单元的运动矢量；基于每个运动补偿单元的运动矢量，获取待处理图像块的重建块。其中，控制点的运动矢量满足 预设的第一运动矢量精度和/或第一运动矢量比特深度。
本申请实施例提出的一种仿射AMVP模式下的精度变化过程，通过提高控制点的运动矢量的精度和比特深度，进行运动补偿，可以有效地提高使用仿射运动模型的编码块的帧间预测准确率。
结合第六方面，在第一种可行的实施方式中，获得待处理图像块的控制点的运动矢量，包括：获取控制点运动矢量预测值之间的差值(control point motion vectors differences，CPMVD)和控制点运动矢量预测值(control point motion vectors predictor，CPMVP)；当CPMVD的精度不等于第一运动矢量精度时，根据CPMVD和第一偏移值，获得待处理图像块的控制点的运动矢量；或者，当CPMVP的精度不等于第一运动矢量精度时，根据CPMVP和第二偏移值，获得待处理图像块的控制点的运动矢量。
示例的，待处理图像块的控制点的运动矢量通过如下公式获得：
CPMV＝CPMVD’+CPMVP’，其中，当CPMVD的精度不等于第一运动矢量精度时，CPMVD’＝CPMVD<<mvrShift1；当CPMVD的精度等于第一运动矢量精度时，CPMVD’＝CPMVD；当CPMVP的精度不等于第一运动矢量精度时，CPMVP’＝CPMVP<<mvrShift2；当CPMVP的精度等于第一运动矢量精度时，CPMVP’＝CPMVP；CPMV表示控制点的运动矢量，mvrShift1表示第一偏移值，mvrShift2表示第二偏移值。
例如，当第一运动矢量精度为1/16像素精度且CPMVD的精度为1/16像素精度时，第一偏移值等于0；当第一运动矢量精度为1/16像素精度且CPMVD的精度为1/4像素精度时，第一偏移值等于2；当第一运动矢量精度为1/16像素精度且CPMVD的精度为整像素精度时，第一偏移值等于4；当第一运动矢量精度为1/16像素精度且CPMVP的精度为1/16像素精度时，第二偏移值等于0；当第一运动矢量精度为1/16像素精度且CPMVP的精度为1/4像素精度时，第二偏移值等于2；当第一运动矢量精度为1/16像素精度且CPMVP的精度为整像素精度时，第二偏移值等于4。
应理解，当第一偏移值等于0或者第二偏移值等于0时，在一种可行的实施方式中，并不进行偏移。
结合上述可实现方式，在第二种可行的实施方式中，当控制点的运动矢量的比特深度大于第一运动矢量比特深度时，对控制点的运动矢量进行钳位以使控制点的运动矢量的比特深度等于第一运动矢量比特深度。
结合上述可实现方式，在第三种可行的实施方式中，对控制点的运动矢量进行钳位以使控制点的运动矢量的比特深度等于第一运动矢量比特深度。
结合上述任意一种可行的实施方式，在第四种可行的实施方式中，方法还包括：处理运动补偿单元的运动矢量精度以满足预设的第二运动矢量精度，和/或，处理运动补偿单元的运动矢量比特深度以满足预设的第二运动矢量精度比特深度；存储处理后的运动补偿单元的运动矢量。
示例的，处理后的运动补偿单元的运动矢量通过如下公式获得：
MCUMV’＝(MCUMV>>mvrShift3)，其中，MCUMV’表示处理后的运动补偿单元的运动矢量，MCUMV表示处理前的运动补偿单元的运动矢量，mvrShift3表示第三偏移值。
例如，当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/16像素精度时，第三偏移值等于2；当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/4像素精度时，第三偏移值等于0；当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/32像素精度时，第三偏移值等于3。
结合上述可实现方式，在第五种可行的实施方式中，还包括：将处理后的运动补偿单元的运动矢量的比特深度进行钳位以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。
结合上述可实现方式，在第六种可行的实施方式中，还包括：当处理后的运动补偿单元的运动矢量的比特深度大于第二运动矢量比特深度时，对处理后的运动补偿单元的运动矢量进行钳位以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。
结合上述任意一种可行的实施方式，在第七种可行的实施方式中，基于每个运动补偿单元的运动矢量，获取待处理图像块的重建块，包括：基于每个运动补偿单元的运动矢量，分别进行运动补偿，以获得待处理图像块的预测块；基于预测块和每个运动补偿单元的运动矢量，获得待处理图像块的重建块。
第七方面，本申请实施例提供了一种帧间预测的方法，包括：在确定待处理图像块的预测模式为基于仿射运动模型的融合(Merge)预测模式之后，获得待处理图像块的控制点的运动矢量；调整控制点的运动矢量以满足预设的第一运动矢量精度和/或第一运动矢量比特深度；根据调整后的控制点的运动矢量，推导待处理图像块中每个运动补偿单元的运动矢量；基于每个运动补偿单元的运动矢量，获取待处理图像块的重建块。
本申请实施例一提出了一种仿射AMVP模式下的精度变化过程，通过提高控制点的运动矢量的精度和比特深度，进行运动补偿，可以有效地提高使用仿射运动模型的编码块的帧间预测准确率。
结合第七方面，在第一种可行的实施方式中，调整控制点的运动矢量，包括：当控制点的运动矢量的精度不等于第一运动矢量精度时，根据控制点的运动矢量和第一偏移值，获得调整后的控制点的运动矢量。
示例的，调整后的控制点的运动矢量通过如下公式获得：
CPMV’＝CPMV<<mvrShift1，其中，CPMV表示控制点的运动矢量，CPMV’表示调整后的控制点的运动矢量，mvrShift1表示第一偏移值。
例如，当第一运动矢量精度为1/16像素精度且控制点的运动矢量的精度为1/16像素精度时，第一偏移值等于0；当第一运动矢量精度为1/16像素精度且控制点的运动矢量的精度为1/4像素精度时，第一偏移值等于2；当第一运动矢量精度为1/16像素精度且控制点的运动矢量的精度为整像素精度时，第一偏移值等于4。
应理解，当第一偏移值等于0时，在一种可行的实施方式中，并不进行偏移。
结合上述可实现方式，在第二种可行的实施方式中，还包括：当调整后的控制点的运动矢量的比特深度大于第一运动矢量比特深度时，对调整后的控制点的运动矢量进行钳位以使调整后的控制点的运动矢量的比特深度等于第一运动矢量比特深度。
结合上述可实现方式，在第三种可行的实施方式中，还包括：对调整后的控制点 的运动矢量进行钳位以使调整后的控制点的运动矢量的比特深度等于第一运动矢量比特深度。
结合第七方面，在第四种可行的实施方式中，待处理图像块的已处理相邻图像块的预测模式为基于仿射运动模型的预测模式，当待处理图像块的控制点的运动矢量是基于已处理相邻图像块的控制点的运动矢量进行推导获得时，调整后的控制点的运动矢量通过如下公式获得：
vx0＝K1>＝0？(K1+offset)>>mvShift:–((–K1+offset)>>mvShift)，
vy0＝K2>＝0？(K2+offset)>>mvShift:–((–K2+offset)>>mvShift)，
vx1＝K3>＝0？(K3+offset)>>mvShift:–((–K3+offset)>>mvShift)，
vy1＝K4>＝0？(K4+offset)>>mvShift:–((–K4+offset)>>mvShift)，
vx2＝K5>＝0？(K5+offset)>>mvShift:–((–K5+offset)>>mvShift)，
vy2＝K6>＝0？(K6+offset)>>mvShift:–((–K6+offset)>>mvShift)，
其中，
K1＝mvScaleHor+dHorX*(x0–x4–M/2)+dHorY*(y0–y4–N/2)，
K2＝mvScaleVer+dVerX*(x0–x4–M/2)+dVerY*(y0–y4–N/2)，
K3＝mvScaleHor+dHorX*(x1–x4–M/2)+dHorY*(y1–y4–N/2)，
K4＝mvScaleVer+dVerX*(x1–x4–M/2)+dVerY*(y1–y4–N/2)，
K5＝mvScaleHor+dHorX*(x2–x4–M/2)+dHorY*(y2–y4–N/2)，
K6＝mvScaleVer+dVerX*(x2–x4–M/2)+dVerY*(y2–y4–N/2)，
offset＝1<<(mvShift–1)，
mvScaleHor＝vx4<<7，
mvScaleVer＝vy4<<7，
dHorX＝(vx5–vx4)<<(7–log2(P))，
dVerX＝(vy5–vy4)<<(7–log2(Q))，
当已处理相邻图像块的仿射运动模型为6参数模型时，dHorY＝(vx6–vx4)<<(7–log2(P))，dVerY＝(vy6–vy4)<<(7–log2(Q))，
当已处理相邻图像块的仿射运动模型为4参数模型时，dHorY＝–dVerX，dVerY＝dHorX，
Log2()表示取2的对数的函数，<<表示左移位，>>表示右移位，P为已处理相邻图像块的宽度、Q为已处理相邻图像块的高度，
(vx0,vy0)、(vx1,vy1)和(vx2,vy2)分别表示待处理图像块的三个控制点的运动矢量的水平分量和竖直分量，即，(vx0,vy0)是待处理图像块的第一个控制点的运动矢量的水平分量和竖直分量，(vx1,vy1)是待处理图像块的第二个控制点的运动矢量的水平分量和竖直分量，(vx2,vy2)是待处理图像块的第三个控制点的运动矢量的水平分量和竖直分量，
(vx4,vy4)、(vx5,vy5)和(vx6,vy6)分别表示已处理相邻图像块的三个控制点的运动矢量的水平分量和竖直分量，即，(vx4,vy4)是已处理相邻图像块的第一个控制点的运动矢量的水平分量和竖直分量，(vx5,vy5)是已处理相邻图像块的第二个控制点的运动矢量的水平分量和竖直分量，(vx6,vy6)是已处理相邻图像块的第三个控制点的运动矢 量的水平分量和竖直分量，
mvShift基于已处理相邻图像块的控制点的运动矢量精度确定。
需要说明的是，相邻图像块可以是指空间相邻的仿射编码块或时域相邻的仿射编码块。
当相邻仿射块存储的CPMV的精度为1/4像素精度时，通过将mvShift设置为5，得到待处理图像块的CPMV的精度为1/16像素精度。当相邻仿射块存储的CPMV的精度为1/4像素精度时，可以将mvShift设置为6，得到待处理图像块的CPMV的精度为1/32像素精度。当相邻仿射块存储的CPMV的精度为1/4像素精度时，可以将mvShift设置为7，得到待处理图像块的CPMV的精度为1/4像素精度。其中，相邻仿射块的CPMV的精度可以是指存储单元的存储的运动矢量精度。
结合上述任意一种可行的实施方式，在第五种可行的实施方式中，方法还包括：处理运动补偿单元的运动矢量精度以满足预设的第二运动矢量精度，和/或，处理运动补偿单元的运动矢量比特深度以满足预设的第二运动矢量精度比特深度；存储处理后的运动补偿单元的运动矢量。
示例的，处理后的运动补偿单元的运动矢量通过如下公式获得：
MCUMV’＝(MCUMV>>mvrShift2)，其中，MCUMV’表示处理后的运动补偿单元的运动矢量，MCUMV表示处理前的运动补偿单元的运动矢量，mvrShift2表示第二偏移值。
例如，当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/16像素精度时，第二偏移值等于2；当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/4像素精度时，第二偏移值等于0；当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/32像素精度时，第二偏移值等于3。
结合上述可实现方式，在第六种可行的实施方式中，还包括：将处理后的运动补偿单元的运动矢量的比特深度进行钳位以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。
结合上述可实现方式，在第七种可行的实施方式中，还包括：当处理后的运动补偿单元的运动矢量的比特深度大于第二运动矢量比特深度时，对处理后的运动补偿单元的运动矢量进行钳位以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。
结合上述任意一种可行的实施方式，在第八种可行的实施方式中，基于每个运动补偿单元的运动矢量，获取待处理图像块的重建块，包括：基于每个运动补偿单元的运动矢量，分别进行运动补偿，以获得待处理图像块的预测块；基于预测块和每个运动补偿单元的运动矢量，获得待处理图像块的重建块。
第八方面，本申请实施例提供了一种帧间预测的装置，包括：确定模块，用于确定待处理图像块的预测模式为基于仿射运动模型的AMVP模式；获取模块，用于获得待处理图像块的控制点的运动矢量，控制点的运动矢量满足预设的第一运动矢量精度和/或第一运动矢量比特深度；计算模块，用于根据控制点的运动矢量，推导待处理图像块中每个运动补偿单元的运动矢量；重建模块，用于基于每个运动补偿单元的运动矢量，获取待处理图像块的重建块。
结合第八方面，在第一种可行的实施方式中，获取模块具体用于：获取CPMVD和CPMVP；当CPMVD的精度不等于第一运动矢量精度时，根据CPMVD和第一偏移值，获得待处理图像块的控制点的运动矢量；或者，当CPMVP的精度不等于第一运动矢量精度时，根据CPMVP和第二偏移值，获得待处理图像块的控制点的运动矢量。
示例的，待处理图像块的控制点的运动矢量通过如下公式获得：
CPMV＝CPMVD’+CPMVP’。当CPMVD的精度不等于第一运动矢量精度时，CPMVD’＝CPMVD<<mvrShift1。当CPMVD的精度等于第一运动矢量精度时，CPMVD’＝CPMVD。当CPMVP的精度不等于第一运动矢量精度时，CPMVP’＝CPMVP<<mvrShift2。当CPMVP的精度等于第一运动矢量精度时，CPMVP’＝CPMVP。其中，CPMV表示控制点的运动矢量，mvrShift1表示第一偏移值，mvrShift2表示第二偏移值。
例如，当第一运动矢量精度为1/16像素精度且CPMVD的精度为1/16像素精度时，第一偏移值等于0；当第一运动矢量精度为1/16像素精度且CPMVD的精度为1/4像素精度时，第一偏移值等于2；当第一运动矢量精度为1/16像素精度且CPMVD的精度为整像素精度时，第一偏移值等于4；当第一运动矢量精度为1/16像素精度且CPMVP的精度为1/16像素精度时，第二偏移值等于0；当第一运动矢量精度为1/16像素精度且CPMVP的精度为1/4像素精度时，第二偏移值等于2；当第一运动矢量精度为1/16像素精度且CPMVP的精度为整像素精度时，第二偏移值等于4。
应理解，当第一偏移值等于0或者第二偏移值等于0时，在一种可行的实施方式中，并不进行偏移。
结合上述可实现方式，在第二种可行的实施方式中，获取模块还用于：当控制点的运动矢量的比特深度大于第一运动矢量比特深度时，对控制点的运动矢量进行钳位以使控制点的运动矢量的比特深度等于第一运动矢量比特深度。
结合上述可实现方式，在第三种可行的实施方式中，获取模块还用于：对控制点的运动矢量进行钳位以使控制点的运动矢量的比特深度等于第一运动矢量比特深度。
结合上述任意一种可行的实施方式，在第四种可行的实施方式中，获取模块还用于：处理运动补偿单元的运动矢量精度以满足预设的第二运动矢量精度，和/或，处理运动补偿单元的运动矢量比特深度以满足预设的第二运动矢量精度比特深度；装置还包括存储模块：存储模块，用于存储处理后的运动补偿单元的运动矢量。
示例的，处理后的运动补偿单元的运动矢量通过如下公式获得：
MCUMV’＝(MCUMV>>mvrShift3)，其中，MCUMV’表示处理后的运动补偿单元的运动矢量，MCUMV表示处理前的运动补偿单元的运动矢量，mvrShift3表示第三偏移值。
例如，当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/16像素精度时，第三偏移值等于2；当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/4像素精度时，第三偏移值等于0；当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/32像素精度时，第三偏移值等于3。
结合上述可实现方式，在第五种可行的实施方式中，获取模块还用于：将处理后的运动补偿单元的运动矢量的比特深度进行钳位以使处理后的运动补偿单元的运动矢 量的比特深度等于第二运动矢量比特深度。
结合上述可实现方式，在第六种可行的实施方式中，获取模块还用于：当处理后的运动补偿单元的运动矢量的比特深度大于第二运动矢量比特深度时，对处理后的运动补偿单元的运动矢量进行钳位以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。
结合上述任意一种可行的实施方式，在第七种可行的实施方式中，重建模块具体用于：基于每个运动补偿单元的运动矢量，分别进行运动补偿，以获得待处理图像块的预测块；基于预测块和每个运动补偿单元的运动矢量，获得待处理图像块的重建块。
第九方面，本申请实施例提供了一种帧间预测的装置，包括：确定模块，用于确定待处理图像块的预测模式为基于仿射运动模型的融合Merge预测模式；获取模块，用于获得待处理图像块的控制点的运动矢量；调整模块，用于调整控制点的运动矢量以满足预设的第一运动矢量精度和/或第一运动矢量比特深度；计算模块，用于根据调整后的控制点的运动矢量，推导待处理图像块中每个运动补偿单元的运动矢量；重建模块，用于基于每个运动补偿单元的运动矢量，获取待处理图像块的重建块。
结合第九方面，在第一种可行的实施方式中，调整模块具体用于：当控制点的运动矢量的精度不等于第一运动矢量精度时，根据控制点的运动矢量和第一偏移值，获得调整后的控制点的运动矢量。
示例的，调整后的控制点的运动矢量通过如下公式获得：
CPMV’＝CPMV<<mvrShift1，其中，CPMV表示控制点的运动矢量，CPMV’表示调整后的控制点的运动矢量，mvrShift1表示第一偏移值。
例如，当第一运动矢量精度为1/16像素精度且控制点的运动矢量的精度为1/16像素精度时，第一偏移值等于0；当第一运动矢量精度为1/16像素精度且控制点的运动矢量的精度为1/4像素精度时，第一偏移值等于2；当第一运动矢量精度为1/16像素精度且控制点的运动矢量的精度为整像素精度时，第一偏移值等于4。
应理解，当第一偏移值等于0时，在一种可行的实施方式中，并不进行偏移。
结合上述可实现方式，在第二种可行的实施方式中，调整模块还用于：当调整后的控制点的运动矢量的比特深度大于第一运动矢量比特深度时，对调整后的控制点的运动矢量进行钳位以使调整后的控制点的运动矢量的比特深度等于第一运动矢量比特深度。
结合上述可实现方式，在第三种可行的实施方式中，调整模块还用于：对调整后的控制点的运动矢量进行钳位以使调整后的控制点的运动矢量的比特深度等于第一运动矢量比特深度。
结合第九方面，在第四种可行的实施方式中，待处理图像块的已处理相邻图像块的预测模式为基于仿射运动模型的预测模式，当待处理图像块的控制点的运动矢量是基于已处理相邻图像块的控制点的运动矢量进行推导获得时，调整后的控制点的运动矢量通过如下公式获得：
vx0＝K1>＝0？(K1+offset)>>mvShift:–((–K1+offset)>>mvShift)，
vy0＝K2>＝0？(K2+offset)>>mvShift:–((–K2+offset)>>mvShift)，
vx1＝K3>＝0？(K3+offset)>>mvShift:–((–K3+offset)>>mvShift)，
vy1＝K4>＝0？(K4+offset)>>mvShift:–((–K4+offset)>>mvShift)，
vx2＝K5>＝0？(K5+offset)>>mvShift:–((–K5+offset)>>mvShift)，
vy2＝K6>＝0？(K6+offset)>>mvShift:–((–K6+offset)>>mvShift)，
其中，
K1＝mvScaleHor+dHorX*(x0–x4–M/2)+dHorY*(y0–y4–N/2)，
K2＝mvScaleVer+dVerX*(x0–x4–M/2)+dVerY*(y0–y4–N/2)，
K3＝mvScaleHor+dHorX*(x1–x4–M/2)+dHorY*(y1–y4–N/2)，
K4＝mvScaleVer+dVerX*(x1–x4–M/2)+dVerY*(y1–y4–N/2)，
K5＝mvScaleHor+dHorX*(x2–x4–M/2)+dHorY*(y2–y4–N/2)，
K6＝mvScaleVer+dVerX*(x2–x4–M/2)+dVerY*(y2–y4–N/2)，
offset＝1<<(mvShift–1)，
mvScaleHor＝vx4<<7，
mvScaleVer＝vy4<<7，
dHorX＝(vx5–vx4)<<(7–log2(P))，
dVerX＝(vy5–vy4)<<(7–log2(Q))，
当已处理相邻图像块的仿射运动模型为6参数模型时，dHorY＝(vx6–vx4)<<(7–log2(P))，dVerY＝(vy6–vy4)<<(7–log2(Q))，
当已处理相邻图像块的仿射运动模型为4参数模型时，dHorY＝–dVerX，dVerY＝dHorX，
Log2()表示取2的对数的函数，<<表示左移位，>>表示右移位，P为已处理相邻图像块的宽度、Q为已处理相邻图像块的高度，
(vx0,vy0)、(vx1,vy1)和(vx2,vy2)分别表示待处理图像块的三个控制点的运动矢量的水平分量和竖直分量，即，(vx0,vy0)是待处理图像块的第一个控制点的运动矢量的水平分量和竖直分量，(vx1,vy1)是待处理图像块的第二个控制点的运动矢量的水平分量和竖直分量，(vx2,vy2)是待处理图像块的第三个控制点的运动矢量的水平分量和竖直分量，
(vx4,vy4)、(vx5,vy5)和(vx6,vy6)分别表示已处理相邻图像块的三个控制点的运动矢量的水平分量和竖直分量，即，(vx4,vy4)是已处理相邻图像块的第一个控制点的运动矢量的水平分量和竖直分量，(vx5,vy5)是已处理相邻图像块的第二个控制点的运动矢量的水平分量和竖直分量，(vx6,vy6)是已处理相邻图像块的第三个控制点的运动矢量的水平分量和竖直分量，
mvShift基于已处理相邻图像块的控制点的运动矢量精度确定。
需要说明的是，相邻图像块可以是指空间相邻的仿射编码块或时域相邻的仿射编码块。
当相邻仿射块存储的CPMV的精度为1/4像素精度时，通过将mvShift设置为5，得到待处理图像块的CPMV的精度为1/16像素精度。当相邻仿射块存储的CPMV的精度为1/4像素精度时，可以将mvShift设置为6，得到待处理图像块的CPMV的精度为1/32像素精度。当相邻仿射块存储的CPMV的精度为1/4像素精度时，可以将mvShift设置为7，得到待处理图像块的CPMV的精度为1/4像素精度。其中，相邻仿射块的 CPMV的精度可以是指存储单元的存储的运动矢量精度。
结合上述任意一种可行的实施方式，在第五种可行的实施方式中，调整模块还用于：处理运动补偿单元的运动矢量精度以满足预设的第二运动矢量精度，和/或，处理运动补偿单元的运动矢量比特深度以满足预设的第二运动矢量精度比特深度；装置还包括存储模块：存储模块，用于存储处理后的运动补偿单元的运动矢量。
示例的，处理后的运动补偿单元的运动矢量通过如下公式获得：
MCUMV’＝(MCUMV>>mvrShift2)，其中，MCUMV’表示处理后的运动补偿单元的运动矢量，MCUMV表示处理前的运动补偿单元的运动矢量，mvrShift2表示第二偏移值。
例如，当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/16像素精度时，第二偏移值等于2；当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/4像素精度时，第二偏移值等于0；当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/32像素精度时，第二偏移值等于3。
结合上述可实现方式，在第六种可行的实施方式中，调整模块还用于：将处理后的运动补偿单元的运动矢量的比特深度进行钳位以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。
结合上述可实现方式，在第七种可行的实施方式中，调整模块还用于：当处理后的运动补偿单元的运动矢量的比特深度大于第二运动矢量比特深度时，对处理后的运动补偿单元的运动矢量进行钳位以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。
结合上述任意一种可行的实施方式，在第八种可行的实施方式中，重建模块具体用于：基于每个运动补偿单元的运动矢量，分别进行运动补偿，以获得待处理图像块的预测块；基于预测块和每个运动补偿单元的运动矢量，获得待处理图像块的重建块。
本申请第十方面，提供一种帧间预测的设备，包括：处理器和耦合于所述处理器的存储器；所述处理器用于执行上述第一方面、第二方面、第六方面或第七方面中任一种可行的实现方式所述的帧间预测的方法。
本申请第十一方面，提供了一种计算机可读存储介质，所述计算机可读存储介质中存储有指令，当所述指令在计算机上运行时，使得计算机执行上述第一方面、第二方面、第六方面或第七方面中任一种可行的实现方式所述的帧间预测的方法。
本申请第十二方面，提供了一种包含指令的计算机程序产品，当所述指令在计算机上运行时，使得计算机执行上述第一方面、第二方面、第六方面或第七方面中任一种可行的实现方式所述的帧间预测的方法。
本申请第十三方面，提供了一种视频图像编码器，所述视频图像编码器包含上述第三方面、第四方面、第五方面、第八方面或第九方面中任一种可行的实现方式所述的帧间预测的装置。
本申请第十四方面，提供了一种视频图像解码器，所述视频图像解码器包含上述第三方面、第四方面、第五方面、第八方面或第九方面中任一种可行的实现方式所述的帧间预测的装置。
另外，上述任意方面的设计方式所带来的技术效果可参见第六方面和第七方面中 不同设计方式所带来的技术效果，此处不再赘述。
本申请实施例中，帧间预测装置的名字对设备本身不构成限定，在实际实现中，这些设备可以以其他名称出现。只要各个设备的功能和本申请实施例类似，属于本申请权利要求及其等同技术的范围之内。
第十五方面，本申请实施例提供了一种帧间预测的方法，包括：获取到待处理图像块的CPMVD和CPMVP后，对CPMVD左移第一偏移值，对CPMVP左移第二偏移值，将左移后的CPMVD和左移后的CPMVP相加，以获得控制点的运动矢量；根据控制点的运动矢量，推导待处理图像块中每个运动补偿单元的运动矢量；基于每个运动补偿单元的运动矢量，获取待处理图像块的重建块。其中，当CPMVD的精度等于第一运动矢量精度时，第一偏移值为0，其中，当CPMVP的精度等于第一运动矢量精度时，第二偏移值为0。
本申请实施例提出的帧间预测的方法，通过提高控制点的运动矢量的精度和比特深度，进行运动补偿，可以有效地提高使用仿射运动模型的编码块的帧间预测准确率。
例如，第一运动矢量精度为1/16像素精度的情况下，当CPMVD的精度为1/16像素精度时，第一偏移值等于0；当CPMVD的精度为1/4像素精度时，第一偏移值等于2；当CPMVD的精度为整像素精度时，第一偏移值等于4；当CPMVP的精度为1/16像素精度时，第二偏移值等于0；当CPMVP的精度为1/4像素精度时，第二偏移值等于2；当CPMVP的精度为整像素精度时，第二偏移值等于4。
在一种可能的设计中，还包括：当控制点的运动矢量的比特深度大于第一运动矢量比特深度时，对控制点的运动矢量进行钳位以使控制点的运动矢量的比特深度等于第一运动矢量比特深度。
在另一种可能的设计中，还包括：对控制点的运动矢量进行钳位以使控制点的运动矢量的比特深度等于第一运动矢量比特深度。
在另一种可能的设计中，方法还包括：处理运动补偿单元的运动矢量以满足预设的第二运动矢量精度；存储处理后的运动补偿单元的运动矢量。
可选的，处理运动补偿单元的运动矢量包括：对运动补偿单元的运动矢量左移第三偏移值。
在另一种可能的设计中，还包括：将处理后的运动补偿单元的运动矢量的比特深度进行钳位以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。
在另一种可能的设计中，还包括：当处理后的运动补偿单元的运动矢量的比特深度大于第二运动矢量比特深度时，对处理后的运动补偿单元的运动矢量进行钳位以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。
例如，第二运动矢量精度为1/4像素精度的情况下，当运动补偿单元的运动矢量的精度为1/16像素精度时，第三偏移值等于2；当运动补偿单元的运动矢量的精度为1/4像素精度时，第三偏移值等于0；当运动补偿单元的运动矢量的精度为1/32像素精度时，第三偏移值等于3。
在另一种可能的设计中，基于每个运动补偿单元的运动矢量，获取待处理图像块的重建块，包括：基于每个运动补偿单元的运动矢量，分别进行运动补偿，以获得待 处理图像块的预测块；基于预测块和每个运动补偿单元的运动矢量，获得待处理图像块的重建块。
第十六方面，本申请实施例提供了一种帧间预测的装置，包括：获取模块，用于获取待处理图像块的控制点的运动矢量差值CPMVD和控制点的运动矢量的预测值CPMVP；获取模块，还用于对CPMVD左移第一偏移值，其中，当CPMVD的精度等于第一运动矢量精度时，第一偏移值为0；获取模块，还用于对CPMVP左移第二偏移值，其中，当CPMVP的精度等于第一运动矢量精度时，第二偏移值为0；获取模块，还用于将左移后的CPMVD和左移后的CPMVP相加，以获得控制点的运动矢量；计算模块，用于根据控制点的运动矢量，推导待处理图像块中每个运动补偿单元的运动矢量；重建模块，用于基于每个运动补偿单元的运动矢量，获取待处理图像块的重建块。
例如，第一运动矢量精度为1/16像素精度的情况下，当CPMVD的精度为1/16像素精度时，第一偏移值等于0；当CPMVD的精度为1/4像素精度时，第一偏移值等于2；当CPMVD的精度为整像素精度时，第一偏移值等于4；当CPMVP的精度为1/16像素精度时，第二偏移值等于0；当CPMVP的精度为1/4像素精度时，第二偏移值等于2；当CPMVP的精度为整像素精度时，第二偏移值等于4。
在一种可能的设计中，获取模块还用于：当控制点的运动矢量的比特深度大于第一运动矢量比特深度时，对控制点的运动矢量进行钳位以使控制点的运动矢量的比特深度等于第一运动矢量比特深度。
在另一种可能的设计中，获取模块还用于：对控制点的运动矢量进行钳位以使控制点的运动矢量的比特深度等于第一运动矢量比特深度。
在另一种可能的设计中，获取模块还用于处理运动补偿单元的运动矢量以满足预设的第二运动矢量精度；装置还包括存储模块。所述存储模块用于存储处理后的运动补偿单元的运动矢量。
可选的，获取模块用于对运动补偿单元的运动矢量左移第三偏移值。
在另一种可能的设计中，获取模块还用于：将处理后的运动补偿单元的运动矢量的比特深度进行钳位以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。
在另一种可能的设计中，获取模块还用于：当处理后的运动补偿单元的运动矢量的比特深度大于第二运动矢量比特深度时，对处理后的运动补偿单元的运动矢量进行钳位以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。
例如，第二运动矢量精度为1/4像素精度的情况下，当运动补偿单元的运动矢量的精度为1/16像素精度时，第三偏移值等于2；当运动补偿单元的运动矢量的精度为1/4像素精度时，第三偏移值等于0；当运动补偿单元的运动矢量的精度为1/32像素精度时，第三偏移值等于3。
在另一种可能的设计中，重建模块具体用于：基于每个运动补偿单元的运动矢量，分别进行运动补偿，以获得待处理图像块的预测块；基于预测块和每个运动补偿单元的运动矢量，获得待处理图像块的重建块。
第十七方面，本申请实施例提供了一种帧间预测的设备，包括：处理器和耦合于 所述处理器的存储器；所述处理器用于执行上述第一方面、第二方面、第六方面、第七方面或第十五方面中任一种可行的实现方式所述的帧间预测的方法。
本申请第十八方面，提供了一种计算机可读存储介质，所述计算机可读存储介质中存储有指令，当所述指令在计算机上运行时，使得计算机执行第一方面、第二方面、第六方面、第七方面或第十五方面中任一种可行的实现方式所述的帧间预测的方法。
本申请第十九方面，提供了一种包含指令的计算机程序产品，当所述指令在计算机上运行时，使得计算机执行上述第一方面、第二方面、第六方面、第七方面或第十五方面中任一种可行的实现方式所述的帧间预测的方法。
本申请第二十方面，提供了一种视频图像编码器，所述视频图像编码器包含上述第三方面、第四方面、第五方面、第八方面、第九方面或第十六方面中任一种可行的实现方式所述的帧间预测的装置。
本申请第二十一方面，提供了一种视频图像解码器，所述视频图像解码器包含上述第三方面、第四方面、第五方面、第八方面、第九方面或第十六方面中任一种可行的实现方式所述的帧间预测的装置。
另外，上述任意方面的设计方式所带来的技术效果可参见第六方面、第七方面和第十六方面中不同设计方式所带来的技术效果，此处不再赘述。
本申请实施例中，帧间预测装置的名字对设备本身不构成限定，在实际实现中，这些设备可以以其他名称出现。只要各个设备的功能和本申请实施例类似，属于本申请权利要求及其等同技术的范围之内。
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具体实施方式
下面结合本申请实施例中的附图对本申请实施例进行描述。以下描述中，参考形成本公开一部分并以说明之方式示出本申请实施例的具体方面或可使用本申请实施例的具体方面的附图。应理解，本申请实施例可在其它方面中使用，并可包括附图中未描绘的结构或逻辑变化。因此，以下详细描述不应以限制性的意义来理解，且本申请的范围由所附权利要求书界定。例如，应理解，结合所描述方法的揭示内容可以同样适用于用于执行所述方法的对应设备或系统，且反之亦然。例如，如果描述一个或多个具体方法步骤，则对应的设备可以包含如功能单元等一个或多个单元，来执行所描述的一个或多个方法步骤(例如，一个单元执行一个或多个步骤，或多个单元，其中每个都执行多个步骤中的一个或多个)，即使附图中未明确描述或说明这种一个或多个单元。另一方面，例如，如果基于如功能单元等一个或多个单元描述具体装置，则对应的方法可以包含一个步骤来执行一个或多个单元的功能性(例如，一个步骤执行一个或多个单元的功能性，或多个步骤，其中每个执行多个单元中一个或多个单元的功能性)，即使附图中未明确描述或说明这种一个或多个步骤。进一步，应理解的是，除非另外明确提出，本文中所描述的各示例性实施例和/或方面的特征可以相互组合。
本申请实施例所涉及的技术方案不仅可能应用于现有的视频编码标准中(如H.264、HEVC等标准)，还可能应用于未来的视频编码标准中(如H.266标准)。本申请的实施方式部分使用的术语仅用于对本申请的具体实施例进行解释，而非旨在限定本申请。下面先对本申请实施例可能涉及的一些概念进行简单介绍。
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。
下面描述本申请实施例所应用的系统架构。参见图1A，图1A示例性地给出了本申请实施例所应用的视频编码及解码系统10的示意性框图。如图1A所示，视频编码及解码系统10可包括源设备12和目的地设备14，源设备12产生经编码视频数据，因此，源设备12可被称为视频编码装置。目的地设备14可对由源设备12所产生的经编码的视频数据进行解码，因此，目的地设备14可被称为视频解码装置。源设备12、目的地设备14或两个的各种实施方案可包含一或多个处理器以及耦合到所述一或多个处理器的存储器。所述存储器可包含但不限于RAM、ROM、EEPROM、快闪存储器或可用于以可由计算机存取的指令或数据结构的形式存储所要的程序代码的任何其它媒体，如本文所描述。源设备12和目的地设备14可以包括各种装置，包含桌上型计算机、移动计算装置、笔记型(例如，膝上型)计算机、平板计算机、机顶盒、例如所谓的“智能”电话等电话手持机、电视机、相机、显示装置、数字媒体播放器、视频游戏控制台、车载计算机、无线通信设备或其类似者。
虽然图1A将源设备12和目的地设备14绘示为单独的设备，但设备实施例也可以同时包括源设备12和目的地设备14或同时包括两者的功能性，即源设备12或对应的功能性以及目的地设备14或对应的功能性。在此类实施例中，可以使用相同硬件和/或软件，或使用单独的硬件和/或软件，或其任何组合来实施源设备12或对应的功能性以及目的地设备14或对应的功能性。
源设备12和目的地设备14之间可通过链路13进行通信连接，目的地设备14可经由链路13从源设备12接收经编码视频数据。链路13可包括能够将经编码视频数据从源设备12移动到目的地设备14的一或多个媒体或装置。在一个实例中，链路13可包括使得源设备12能够实时将经编码视频数据直接发射到目的地设备14的一或多个通信媒体。在此实例中，源设备12可根据通信标准(例如无线通信协议)来调制经编码视频数据，且可将经调制的视频数据发射到目的地设备14。所述一或多个通信媒体可包含无线和/或有线通信媒体，例如射频(RF)频谱或一或多个物理传输线。所述一或多个通信媒体可形成基于分组的网络的一部分，基于分组的网络例如为局域网、广域网或全球网络(例如，因特网)。所述一或多个通信媒体可包含路由器、交换器、基站或促进从源设备12到目的地设备14的通信的其它设备。
源设备12包括编码器20，另外可选地，源设备12还可以包括图片源16、图片预处理器18、以及通信接口22。具体实现形态中，所述编码器20、图片源16、图片预处理器18、以及通信接口22可能是源设备12中的硬件部件，也可能是源设备12中的软件程序。分别描述如下：
图片源16，可以包括或可以为任何类别的图片捕获设备，用于例如捕获现实世界图片，和/或任何类别的图片或评论(对于屏幕内容编码，屏幕上的一些文字也认为是待编码的图片或图像的一部分)生成设备，例如，用于生成计算机动画图片的计算机图形处理器，或用于获取和/或提供现实世界图片、计算机动画图片(例如，屏幕内容、虚拟现实(virtual reality，VR)图片)的任何类别设备，和/或其任何组合(例如，实景(augmented reality，AR)图片)。图片源16可以为用于捕获图片的相机或者用于存储图片的存储器，图片源16还可以包括存储先前捕获或产生的图片和/或获取或接收图片的任何类别的(内部或外部)接口。当图片源16为相机时，图片源16可例如为本地的或集成在源设备中的集成相机；当图片源16为存储器时，图片源16可为本地的或例如集成在源设备中的集成存储器。当所述图片源16包括接口时，接口可例如为从外部视频源接收图片的外部接口，外部视频源例如为外部图片捕获设备，比如相机、外部存储器或外部图片生成设备，外部图片生成设备例如为外部计算机图形处理器、计算机或服务器。接口可以为根据任何专有或标准化接口协议的任何类别的接口，例如有线或无线接口、光接口。
其中，图片可以视为像素点(picture element)的二维阵列或矩阵。阵列中的像素点也可以称为采样点。阵列或图片在水平和垂直方向(或轴线)上的采样点数目定义图片的尺寸和/或分辨率。为了表示颜色，通常采用三个颜色分量，即图片可以表示为或包含三个采样阵列。例如在RBG格式或颜色空间中，图片包括对应的红色、绿色及蓝色采样阵列。但是，在视频编码中，每个像素通常以亮度/色度格式或颜色空间表示，例如对于YUV格式的图片，包括Y指示的亮度分量(有时也可以用L指示)以及U 和V指示的两个色度分量。亮度(luma)分量Y表示亮度或灰度水平强度(例如，在灰度等级图片中两者相同)，而两个色度(chroma)分量U和V表示色度或颜色信息分量。相应地，YUV格式的图片包括亮度采样值(Y)的亮度采样阵列，和色度值(U和V)的两个色度采样阵列。RGB格式的图片可以转换或变换为YUV格式，反之亦然，该过程也称为色彩变换或转换。如果图片是黑白的，该图片可以只包括亮度采样阵列。本申请实施例中，由图片源16传输至图片处理器的图片也可称为原始图片数据17。
图片预处理器18，用于接收原始图片数据17并对原始图片数据17执行预处理，以获取经预处理的图片19或经预处理的图片数据19。例如，图片预处理器18执行的预处理可以包括整修、色彩格式转换(例如，从RGB格式转换为YUV格式)、调色或去噪。
编码器20(或称视频编码器20)，用于接收经预处理的图片数据19，采用相关预测模式(如本文各个实施例中的预测模式)对经预处理的图片数据19进行处理，从而提供经编码图片数据21(下文将进一步基于图2或图4或图5描述编码器20的结构细节)。在一些实施例中，编码器20可以用于执行后文所描述的各个实施例，以实现本申请所描述的色度块预测方法在编码侧的应用。
通信接口22，可用于接收经编码图片数据21，并可通过链路13将经编码图片数据21传输至目的地设备14或任何其它设备(如存储器)，以用于存储或直接重构，所述其它设备可为任何用于解码或存储的设备。通信接口22可例如用于将经编码图片数据21封装成合适的格式，例如数据包，以在链路13上传输。
目的地设备14包括解码器30，另外可选地，目的地设备14还可以包括通信接口28、图片后处理器32和显示设备34。分别描述如下：
通信接口28，可用于从源设备12或任何其它源接收经编码图片数据21，所述任何其它源例如为存储设备，存储设备例如为经编码图片数据存储设备。通信接口28可以用于藉由源设备12和目的地设备14之间的链路13或藉由任何类别的网络传输或接收经编码图片数据21，链路13例如为直接有线或无线连接，任何类别的网络例如为有线或无线网络或其任何组合，或任何类别的私网和公网，或其任何组合。通信接口28可以例如用于解封装通信接口22所传输的数据包以获取经编码图片数据21。
通信接口28和通信接口22都可以配置为单向通信接口或者双向通信接口，以及可以用于例如发送和接收消息来建立连接、确认和交换任何其它与通信链路和/或例如经编码图片数据传输的数据传输有关的信息。
解码器30(或称为解码器30)，用于接收经编码图片数据21并提供经解码图片数据31或经解码图片31(下文将进一步基于图3或图4或图5描述解码器30的结构细节)。在一些实施例中，解码器30可以用于执行后文所描述的各个实施例，以实现本申请所描述的色度块预测方法在解码侧的应用。
图片后处理器32，用于对经解码图片数据31(也称为经重构图片数据)执行后处理，以获得经后处理图片数据33。图片后处理器32执行的后处理可以包括：色彩格式转换(例如，从YUV格式转换为RGB格式)、调色、整修或重采样，或任何其它处理，还可用于将将经后处理图片数据33传输至显示设备34。
显示设备34，用于接收经后处理图片数据33以向例如用户或观看者显示图片。显示设备34可以为或可以包括任何类别的用于呈现经重构图片的显示器，例如，集成的或外部的显示器或监视器。例如，显示器可以包括液晶显示器(liquid crystal display，LCD)、有机发光二极管(organic light emitting diode，OLED)显示器、等离子显示器、投影仪、微LED显示器、硅基液晶(liquid crystal on silicon，LCoS)、数字光处理器(digital light processor，DLP)或任何类别的其它显示器。
虽然，图1A将源设备12和目的地设备14绘示为单独的设备，但设备实施例也可以同时包括源设备12和目的地设备14或同时包括两者的功能性，即源设备12或对应的功能性以及目的地设备14或对应的功能性。在此类实施例中，可以使用相同硬件和/或软件，或使用单独的硬件和/或软件，或其任何组合来实施源设备12或对应的功能性以及目的地设备14或对应的功能性。
本领域技术人员基于描述明显可知，不同单元的功能性或图1A所示的源设备12和/或目的地设备14的功能性的存在和(准确)划分可能根据实际设备和应用有所不同。源设备12和目的地设备14可以包括各种设备中的任一个，包含任何类别的手持或静止设备，例如，笔记本或膝上型计算机、移动电话、智能手机、平板或平板计算机、摄像机、台式计算机、机顶盒、电视机、相机、车载设备、显示设备、数字媒体播放器、视频游戏控制台、视频流式传输设备(例如内容服务服务器或内容分发服务器)、广播接收器设备、广播发射器设备等，并可以不使用或使用任何类别的操作系统。
编码器20和解码器30都可以实施为各种合适电路中的任一个，例如，一个或多个微处理器、数字信号处理器(digital signal processor，DSP)、专用集成电路(application-specific integrated circuit，ASIC)、现场可编程门阵列(field-programmable gate array，FPGA)、离散逻辑、硬件或其任何组合。如果部分地以软件实施所述技术，则设备可将软件的指令存储于合适的非暂时性计算机可读存储介质中，且可使用一或多个处理器以硬件执行指令从而执行本公开的技术。前述内容(包含硬件、软件、硬件与软件的组合等)中的任一者可视为一或多个处理器。
在一些情况下，图1A中所示视频编码及解码系统10仅为示例，本申请的技术可以适用于不必包含编码和解码设备之间的任何数据通信的视频编码设置(例如，视频编码或视频解码)。在其它实例中，数据可从本地存储器检索、在网络上流式传输等。视频编码设备可以对数据进行编码并且将数据存储到存储器，和/或视频解码设备可以从存储器检索数据并且对数据进行解码。在一些实例中，由并不彼此通信而是仅编码数据到存储器和/或从存储器检索数据且解码数据的设备执行编码和解码。
参见图1B，图1B是根据一示例性实施例的包含图2的编码器20和/或图3的解码器30的视频译码系统40的实例的说明图。视频译码系统40可以实现本申请实施例的各种技术的组合。在所说明的实施方式中，视频译码系统40可以包含成像设备41、编码器20、解码器30(和/或藉由处理单元46的逻辑电路47实施的视频编/解码器)、天线42、一个或多个处理器43、一个或多个存储器44和/或显示设备45。
如图1B所示，成像设备41、天线42、处理单元46、逻辑电路47、编码器20、解码器30、处理器43、存储器44和/或显示设备45能够互相通信。如所论述，虽然 用编码器20和解码器30绘示视频译码系统40，但在不同实例中，视频译码系统40可以只包含编码器20或只包含解码器30。
在一些实例中，天线42可以用于传输或接收视频数据的经编码比特流。另外，在一些实例中，显示设备45可以用于呈现视频数据。在一些实例中，逻辑电路47可以通过处理单元46实施。处理单元46可以包含专用集成电路(application-specific integrated circuit，ASIC)逻辑、图形处理器、通用处理器等。视频译码系统40也可以包含可选的处理器43，该可选处理器43类似地可以包含专用集成电路(application-specific integrated circuit，ASIC)逻辑、图形处理器、通用处理器等。在一些实例中，逻辑电路47可以通过硬件实施，如视频编码专用硬件等，处理器43可以通过通用软件、操作系统等实施。另外，存储器44可以是任何类型的存储器，例如易失性存储器(例如，静态随机存取存储器(Static Random Access Memory，SRAM)、动态随机存储器(Dynamic Random Access Memory，DRAM)等)或非易失性存储器(例如，闪存等)等。在非限制性实例中，存储器44可以由超速缓存内存实施。在一些实例中，逻辑电路47可以访问存储器44(例如用于实施图像缓冲器)。在其它实例中，逻辑电路47和/或处理单元46可以包含存储器(例如，缓存等)用于实施图像缓冲器等。
在一些实例中，通过逻辑电路实施的编码器20可以包含(例如，通过处理单元46或存储器44实施的)图像缓冲器和(例如，通过处理单元46实施的)图形处理单元。图形处理单元可以通信耦合至图像缓冲器。图形处理单元可以包含通过逻辑电路47实施的编码器20，以实施参照图2和/或本文中所描述的任何其它编码器系统或子系统所论述的各种模块。逻辑电路可以用于执行本文所论述的各种操作。
在一些实例中，解码器30可以以类似方式通过逻辑电路47实施，以实施参照图3的解码器30和/或本文中所描述的任何其它解码器系统或子系统所论述的各种模块。在一些实例中，逻辑电路实施的解码器30可以包含(通过处理单元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实施的解码器30，以实施参照图3和/或本文中所描述的任何其它解码器系统或子系统所论述的各种模块。
在一些实例中，天线42可以用于接收视频数据的经编码比特流。如所论述，经编码比特流可以包含本文所论述的与编码视频帧相关的数据、指示符、索引值、模式选择数据等，例如与编码分割相关的数据(例如，变换系数或经量化变换系数，(如所论述的)可选指示符，和/或定义编码分割的数据)。视频译码系统40还可包含耦合至天线42并用于解码经编码比特流的解码器30。显示设备45用于呈现视频帧。
应理解，本申请实施例中对于参考编码器20所描述的实例，解码器30可以用于执行相反过程。关于信令语法元素，解码器30可以用于接收并解析这种语法元素，相应地解码相关视频数据。在一些例子中，编码器20可以将语法元素熵编码成经编码视频比特流。在此类实例中，解码器30可以解析这种语法元素，并相应地解码相关视频数据。
需要说明的是，本申请实施例描述的方法主要用于帧间预测过程，此过程在编码 器20和解码器30均存在，本申请实施例中的编码器20和解码器30可以是例如H.263、H.264、HEVV、MPEG-2、MPEG-4、VP8、VP9等视频标准协议或者下一代视频标准协议(如H.266等)对应的编/解码器。
参见图2，图2示出用于实现本申请实施例的编码器20的实例的示意性/概念性框图。在图2的实例中，编码器20包括残差计算单元204、变换处理单元206、量化单元208、逆量化单元210、逆变换处理单元212、重构单元214、缓冲器216、环路滤波器单元220、经解码图片缓冲器(decoded picture buffer，DPB)230、预测处理单元260和熵编码单元270。预测处理单元260可以包含帧间预测单元244、帧内预测单元254和模式选择单元262。帧间预测单元244可以包含运动估计单元和运动补偿单元(未图示)。图2所示的编码器20也可以称为混合型视频编码器或根据混合型视频编解码器的视频编码器。
例如，残差计算单元204、变换处理单元206、量化单元208、预测处理单元260和熵编码单元270形成编码器20的前向信号路径，而例如逆量化单元210、逆变换处理单元212、重构单元214、缓冲器216、环路滤波器220、经解码图片缓冲器(decoded picture buffer，DPB)230、预测处理单元260形成编码器的后向信号路径，其中编码器的后向信号路径对应于解码器的信号路径(参见图3中的解码器30)。
编码器20通过例如输入202，接收图片201或图片201的图像块203，例如，形成视频或视频序列的图片序列中的图片。图像块203也可以称为当前图片块或待编码图片块，图片201可以称为当前图片或待编码图片(尤其是在视频编码中将当前图片与其它图片区分开时，其它图片例如同一视频序列亦即也包括当前图片的视频序列中的先前经编码和/或经解码图片)。
编码器20的实施例可以包括分割单元(图2中未绘示)，用于将图片201分割成多个例如图像块203的块，通常分割成多个不重叠的块。分割单元可以用于对视频序列中所有图片使用相同的块大小以及定义块大小的对应栅格，或用于在图片或子集或图片群组之间更改块大小，并将每个图片分割成对应的块。
在一个实例中，编码器20的预测处理单元260可以用于执行上述分割技术的任何组合。
如图片201，图像块203也是或可以视为具有采样值的采样点的二维阵列或矩阵，虽然其尺寸比图片201小。换句话说，图像块203可以包括，例如，一个采样阵列(例如黑白图片201情况下的亮度阵列)或三个采样阵列(例如，彩色图片情况下的一个亮度阵列和两个色度阵列)或依据所应用的色彩格式的任何其它数目和/或类别的阵列。图像块203的水平和垂直方向(或轴线)上采样点的数目定义图像块203的尺寸。
如图2所示的编码器20用于逐块编码图片201，例如，对每个图像块203执行编码和预测。
残差计算单元204用于基于图片图像块203和预测块265(下文提供预测块265的其它细节)计算残差块205，例如，通过逐样本(逐像素)将图像块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单元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DBP 230中的至少部分经解码图片)和其它帧间预测参数，例如取决于是否使用整个参考图片或只使用参考图片的一部分，例如围绕当前块的区域的搜索窗区域，来搜索最佳匹配参考块，和/或例如取决于是否应用如半像素和/或四分之一像素内插的像素内插，帧间预测模式集合例如可包括先进运动矢量(Advanced Motion Vector Prediction，AMVP)模式和融合(merge)模式。具体实施中，帧间预测模式集合可包括本申请实施例改进的基于控制点的先进的运动矢量预测(advanced motion vector prediction，AMVP)模式，以及，改进的基于控制点的融合(merge)模式。在一个实例中，帧内预测单元254可以用于执行下文描述的帧间预测技术的任意组合。
除了以上预测模式，本申请实施例也可以应用跳过模式和/或直接模式。
预测处理单元260可以进一步用于将图像块203分割成较小的块分区或子块，例如，通过迭代使用四叉树(quad-tree，QT)分割、二进制树(binary-tree，BT)分割或三叉树(triple-tree，TT)分割，或其任何组合，以及用于例如为块分区或子块中的每一个执行预测，其中模式选择包括选择分割的图像块203的树结构和选择应用于块分区或子块中的每一个的预测模式。
帧间预测单元244可以包含运动估计(motion estimation，ME)单元(图2中未示出)和运动补偿(motion compensation，MC)单元(图2中未示出)。运动估计单元用于接收或获取图片图像块203(当前图片201的当前图片图像块203)和经解码图片231，或至少一个或多个先前经重构块，例如，一个或多个其它/不同先前经解码图片231的经重构块，来进行运动估计。例如，视频序列可以包括当前图片和先前经解码图片31，或换句话说，当前图片和先前经解码图片31可以是形成视频序列的图片序列的一部分，或者形成该图片序列。
例如，编码器20可以用于从多个其它图片中的同一或不同图片的多个参考块中选 择参考块，并向运动估计单元(图2中未示出)提供参考图片和/或提供参考块的位置(X、Y坐标)与当前块的位置之间的偏移(空间偏移)作为帧间预测参数。该偏移也称为运动向量(motion vector，MV)。
运动补偿单元用于获取帧间预测参数，并基于或使用帧间预测参数执行帧间预测来获取帧间预测块245。由运动补偿单元(图2中未示出)执行的运动补偿可以包含基于通过运动估计(可能执行对子像素精确度的内插)确定的运动/块向量取出或生成预测块。内插滤波可从已知像素样本产生额外像素样本，从而潜在地增加可用于编码图片块的候选预测块的数目。一旦接收到用于当前图片块的PU的运动向量，运动补偿单元246可以在一个参考图片列表中定位运动向量指向的预测块。运动补偿单元246还可以生成与块和视频条带相关联的语法元素，以供解码器30在解码视频条带的图片块时使用。
具体的，上述帧间预测单元244可向熵编码单元270传输语法元素，所述语法元素包括帧间预测参数(比如遍历多个帧间预测模式后选择用于当前块预测的帧间预测模式的指示信息)。可能应用场景中，如果帧间预测模式只有一种，那么也可以不在语法元素中携带帧间预测参数，此时解码端30可直接使用默认的预测模式进行解码。可以理解的，帧间预测单元244可以用于执行帧间预测技术的任意组合。
帧内预测单元254用于获取，例如接收同一图片的图片块203(当前图片块)和一个或多个先前经重构块，例如经重构相相邻块，以进行帧内估计。例如，编码器20可以用于从多个(预定)帧内预测模式中选择帧内预测模式。
编码器20的实施例可以用于基于优化标准选择帧内预测模式，例如基于最小残差(例如，提供最类似于当前图片块203的预测块255的帧内预测模式)或最小码率失真。
帧内预测单元254进一步用于基于如所选择的帧内预测模式的帧内预测参数确定帧内预测块255。在任何情况下，在选择用于块的帧内预测模式之后，帧内预测单元254还用于向熵编码单元270提供帧内预测参数，即提供指示所选择的用于块的帧内预测模式的信息。在一个实例中，帧内预测单元254可以用于执行帧内预测技术的任意组合。
具体的，上述帧内预测单元254可向熵编码单元270传输语法元素，所述语法元素包括帧内预测参数(比如遍历多个帧内预测模式后选择用于当前块预测的帧内预测模式的指示信息)。可能应用场景中，如果帧内预测模式只有一种，那么也可以不在语法元素中携带帧内预测参数，此时解码端30可直接使用默认的预测模式进行解码。
熵编码单元270用于将熵编码算法或方案(例如，可变长度编码(variable length coding，VLC)方案、上下文自适应VLC(context adaptive VLC，CAVLC)方案、算术编码方案、上下文自适应二进制算术编码(context adaptive binary arithmetic coding，CABAC)、基于语法的上下文自适应二进制算术编码(syntax-based context-adaptive binary arithmetic coding，SBAC)、概率区间分割熵(probability interval partitioning entropy，PIPE)编码或其它熵编码方法或技术)应用于经量化残差系数209、帧间预测参数、帧内预测参数和/或环路滤波器参数中的单个或所有上(或不应用)，以获取可以通过输出272以例如经编码比特流21的形式输出的经编码图片数据21。可以将 经编码比特流传输到视频解码器30，或将其存档稍后由视频解码器30传输或检索。熵编码单元270还可用于熵编码正被编码的当前视频条带的其它语法元素。
视频编码器20的其它结构变型可用于编码视频流。例如，基于非变换的编码器20可以在没有针对某些块或帧的变换处理单元206的情况下直接量化残差信号。在另一实施方式中，编码器20可具有组合成单个单元的量化单元208和逆量化单元210。
具体的，在本申请实施例中，编码器20可用于实现后文实施例中描述的帧间预测方法。
应当理解的是，视频编码器20的其它的结构变化可用于编码视频流。例如，对于某些图像块或者图像帧，视频编码器20可以直接地量化残差信号而不需要经变换处理单元206处理，相应地也不需要经逆变换处理单元212处理；或者，对于某些图像块或者图像帧，视频编码器20没有产生残差数据，相应地不需要经变换处理单元206、量化单元208、逆量化单元210和逆变换处理单元212处理；或者，视频编码器20可以将经重构图像块作为参考块直接地进行存储而不需要经环路滤波器220处理；或者，视频编码器20中量化单元208和逆量化单元210可以合并在一起。环路滤波器220是可选的，以及针对无损压缩编码的情况下，变换处理单元206、量化单元208、逆量化单元210和逆变换处理单元212是可选的。应当理解的是，根据不同的应用场景，帧间预测单元244和帧内预测单元254可以是被选择性的启用。
参见图3，图3示出用于实现本申请实施例的解码器30的实例的示意性/概念性框图。视频解码器30用于接收例如由编码器20编码的经编码图片数据(例如，经编码比特流)21，以获取经解码图片231。在解码过程期间，视频解码器30从视频编码器20接收视频数据，例如表示经编码视频条带的图片块的经编码视频比特流及相关联的语法元素。
在图3的实例中，解码器30包括熵解码单元304、逆量化单元310、逆变换处理单元312、重构单元314(例如求和器314)、缓冲器316、环路滤波器320、经解码图片缓冲器330以及预测处理单元360。预测处理单元360可以包含帧间预测单元344、帧内预测单元354和模式选择单元362。在一些实例中，视频解码器30可执行大体上与参照图2的视频编码器20描述的编码遍次互逆的解码遍次。
熵解码单元304用于对经编码图片数据21执行熵解码，以获取例如经量化系数309和/或经解码的编码参数(图3中未示出)，例如，帧间预测、帧内预测参数、环路滤波器参数和/或其它语法元素中(经解码)的任意一个或全部。熵解码单元304进一步用于将帧间预测参数、帧内预测参数和/或其它语法元素转发至预测处理单元360。视频解码器30可接收视频条带层级和/或视频块层级的语法元素。
逆量化单元310功能上可与逆量化单元210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/或从经编码图片数据 21获取预测块365，以及从例如熵解码单元304(显式地或隐式地)接收或获取预测相关参数和/或关于所选择的预测模式的信息。
当视频条带经编码为经帧内编码(I)条带时，预测处理单元360的帧内预测单元354用于基于信号表示的帧内预测模式及来自当前帧或图片的先前经解码块的数据来产生用于当前视频条带的图片块的预测块365。当视频帧经编码为经帧间编码(即B或P)条带时，预测处理单元360的帧间预测单元344(例如，运动补偿单元)用于基于运动向量及从熵解码单元304接收的其它语法元素生成用于当前视频条带的视频块的预测块365。对于帧间预测，可从一个参考图片列表内的一个参考图片中产生预测块。视频解码器30可基于存储于DPB 330中的参考图片，使用默认建构技术来建构参考帧列表：列表0和列表1。
预测处理单元360用于通过解析运动向量和其它语法元素，确定用于当前视频条带的视频块的预测信息，并使用预测信息产生用于正经解码的当前视频块的预测块。在本申请的一实例中，预测处理单元360使用接收到的一些语法元素确定用于编码视频条带的视频块的预测模式(例如，帧内或帧间预测)、帧间预测条带类型(例如，B条带、P条带或GPB条带)、用于条带的参考图片列表中的一个或多个的建构信息、用于条带的每个经帧间编码视频块的运动向量、条带的每个经帧间编码视频块的帧间预测状态以及其它信息，以解码当前视频条带的视频块。在本公开的另一实例中，视频解码器30从比特流接收的语法元素包含接收自适应参数集(adaptive parameter set，APS)、序列参数集(sequence parameter set，SPS)、图片参数集(picture parameter set，PPS)或条带标头中的一个或多个中的语法元素。
逆量化单元310可用于逆量化(即，反量化)在比特流中提供且由熵解码单元304解码的经量化变换系数。逆量化过程可包含使用由视频编码器20针对视频条带中的每一视频块所计算的量化参数来确定应该应用的量化程度并同样确定应该应用的逆量化程度。
逆变换处理单元312用于将逆变换(例如，逆DCT、逆整数变换或概念上类似的逆变换过程)应用于变换系数，以便在像素域中产生残差块。
重构单元314(例如，求和器314)用于将逆变换块313(即经重构残差块313)添加到预测块365，以在样本域中获取经重构块315，例如通过将经重构残差块313的样本值与预测块365的样本值相加。
环路滤波器单元320(在编码循环期间或在编码循环之后)用于对经重构块315进行滤波以获取经滤波块321，从而顺利进行像素转变或提高视频质量。在一个实例中，环路滤波器单元320可以用于执行下文描述的滤波技术的任意组合。环路滤波器单元320旨在表示一个或多个环路滤波器，例如去块滤波器、样本自适应偏移(sample-adaptive offset，SAO)滤波器或其它滤波器，例如双边滤波器、自适应环路滤波器(adaptive loop filter，ALF)，或锐化或平滑滤波器，或协同滤波器。尽管环路滤波器单元320在图3中示出为环内滤波器，但在其它配置中，环路滤波器单元320可实施为环后滤波器。
随后将给定帧或图片中的经解码视频块321存储在存储用于后续运动补偿的参考图片的经解码图片缓冲器330中。
解码器30用于例如，藉由输出332输出经解码图片31，以向用户呈现或供用户查看。
视频解码器30的其它变型可用于对压缩的比特流进行解码。例如，解码器30可以在没有环路滤波器单元320的情况下生成输出视频流。例如，基于非变换的解码器30可以在没有针对某些块或帧的逆变换处理单元312的情况下直接逆量化残差信号。在另一实施方式中，视频解码器30可以具有组合成单个单元的逆量化单元310和逆变换处理单元312。
具体的，在本申请实施例中，解码器30用于实现后文实施例中描述的帧间预测方法。
应当理解的是，视频解码器30的其它结构变化可用于解码经编码视频位流。例如，视频解码器30可以不经滤波器320处理而生成输出视频流；或者，对于某些图像块或者图像帧，视频解码器30的熵解码单元304没有解码出经量化的系数，相应地不需要经逆量化单元310和逆变换处理单元312处理。环路滤波器320是可选的；以及针对无损压缩的情况下，逆量化单元310和逆变换处理单元312是可选的。应当理解的是，根据不同的应用场景，帧间预测单元和帧内预测单元可以是被选择性的启用。
应当理解的是，本申请的编码器20和解码器30中，针对某个环节的处理结果可以经过进一步处理后，输出到下一个环节，例如，在插值滤波、运动矢量推导或环路滤波等环节之后，对相应环节的处理结果进一步进行Clip或移位shift等操作。
例如，按照相邻仿射编码块的运动矢量推导得到的当前图像块的控制点的运动矢量，可以经过进一步处理，本申请对此不做限定。例如，对运动矢量的取值范围进行约束，使其在一定的位宽内。假设允许的运动矢量的位宽为比特深度(bitDepth)，则运动矢量的取值范围为-2^(bitDepth-1)～2^(bitDepth-1)-1，其中“^”符号表示幂次方。如bitDepth为16，则取值范围为-32768～32767。如bitDepth为18，则取值范围为
-131072～131071。可以通过以下两种方式进行约束：
方式1，将运动矢量溢出的高位去除：
ux＝(vx+2 bitDepth)％2 bitDepth
vx＝(ux>＝2 bitDepth-1)？(ux-2 bitDepth):ux
uy＝(vy+2 bitDepth)％2 bitDepth
vy＝(uy>＝2 bitDepth-1)？(uy-2 bitDepth):uy
例如vx的值为-32769，通过以上公式得到的为32767。因为在计算机中，数值是以二进制的补码形式存储的，-32769的二进制补码为1,0111,1111,1111,1111(17位)，计算机对于溢出的处理为丢弃高位，则vx的值为0111,1111,1111,1111，则为32767，与通过公式处理得到的结果一致。
方法2，将运动矢量进行Clipping，如以下公式所示：
vx＝Clip3(-2 bitDepth-1,2 bitDepth-1-1,vx)
vy＝Clip3(-2 bitDepth-1,2 bitDepth-1-1,vy)
其中Clip3的定义为，表示将z的值钳位到区间[x,y]之间：
Figure PCTCN2019127669-appb-000001
参见图4，图4是本申请实施例提供的视频译码设备400(例如视频编码设备400或视频解码设备400)的结构示意图。视频译码设备400适于实施本文所描述的实施例。在一个实施例中，视频译码设备400可以是视频解码器(例如图1A的解码器30)或视频编码器(例如图1A的编码器20)。在另一个实施例中，视频译码设备400可以是上述图1A的解码器30或图1A的编码器20中的一个或多个组件。
视频译码设备400包括：用于接收数据的入口端口410和接收器单元(Rx)420，用于处理数据的处理器、逻辑单元或中央处理器(CPU)430，用于传输数据的发射器单元(Tx)440和出口端口450，以及，用于存储数据的存储器460。视频译码设备400还可以包括与入口端口410、接收器单元420、发射器单元440和出口端口450耦合的光电转换组件和电光(EO)组件，用于光信号或电信号的出口或入口。
处理器430通过硬件和软件实现。处理器430可以实现为一个或多个CPU芯片、核(例如，多核处理器)、FPGA、ASIC和DSP。处理器430与入口端口410、接收器单元420、发射器单元440、出口端口450和存储器460通信。处理器430包括译码模块470(例如编码模块470或解码模块470)。编码/解码模块470实现本文中所公开的实施例，以实现本申请实施例所提供的色度块预测方法。例如，编码/解码模块470实现、处理或提供各种编码操作。因此，通过编码/解码模块470为视频译码设备400的功能提供了实质性的改进，并影响了视频译码设备400到不同状态的转换。或者，以存储在存储器460中并由处理器430执行的指令来实现编码/解码模块470。
存储器460包括一个或多个磁盘、磁带机和固态硬盘，可以用作溢出数据存储设备，用于在选择性地执行这些程序时存储程序，并存储在程序执行过程中读取的指令和数据。存储器460可以是易失性和/或非易失性的，可以是只读存储器(ROM)、随机存取存储器(RAM)、随机存取存储器(ternary content-addressable memory，TCAM)和/或静态随机存取存储器(SRAM)。
参见图5，图5是根据一示例性实施例的可用作图1A中的源设备12和目的地设备14中的任一个或两个的装置500的简化框图。装置500可以实现本申请的技术。换言之，图5为本申请实施例的编码设备或解码设备(简称为译码设备500)的一种实现方式的示意性框图。其中，译码设备500可以包括处理器510、存储器530和总线系统550。其中，处理器和存储器通过总线系统相连，该存储器用于存储指令，该处理器用于执行该存储器存储的指令。译码设备的存储器存储程序代码，且处理器可以调用存储器中存储的程序代码执行本申请描述的各种视频编码或解码方法。为避免重复，这里不再详细描述。
在本申请实施例中，该处理器510可以是中央处理单元(Central Processing Unit，简称为“CPU”)，该处理器510还可以是其他通用处理器、数字信号处理器(DSP)、专用集成电路(ASIC)、现成可编程门阵列(FPGA)或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件等。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。
该存储器530可以包括只读存储器(ROM)设备或者随机存取存储器(RAM)设备。任何其他适宜类型的存储设备也可以用作存储器530。存储器530可以包括由处理器510使用总线550访问的代码和数据531。存储器530可以进一步包括操作系统533 和应用程序535，该应用程序535包括允许处理器510执行本申请描述的视频编码或解码方法的至少一个程序。例如，应用程序535可以包括应用1至N，其进一步包括执行在本申请描述的视频编码或解码方法的视频编码或解码应用(简称视频译码应用)。
该总线系统550除包括数据总线之外，还可以包括电源总线、控制总线和状态信号总线等。但是为了清楚说明起见，在图中将各种总线都标为总线系统550。
可选的，译码设备500还可以包括一个或多个输出设备，诸如显示器570。在一个示例中，显示器570可以是触感显示器，其将显示器与可操作地感测触摸输入的触感单元合并。显示器570可以经由总线550连接到处理器510。
下面首先对本申请中涉及到的概念进行描述。
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(记为邻块)，根据各个邻块的运动信息构建候选运动矢量列表。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。例如，将率失真代价最小的候选运动信息确定为最优的运动矢量，将最优的运动矢量作为当前块的运动矢量预测值(motion vector predictor，MVP)。其中，邻块的位置及其遍历顺序都是预先定义的。率失真代价可以采用公式(1)计算获得。
J＝SAD+λR        (1)
其中，J表示率失真代价，SAD表示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。
对于Merge模式，先遍历当前块空域或者时域相邻的已编码块(记为邻块)，根据各个邻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矢量运动信息。具体的可以参考上述AMVP模式中的阐述。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(可以记为merge index)传递到解码端。例如，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)。若相邻块不可得(相邻块不存在或者相邻块未编码或者相邻块采用的预测模式不为帧间预测模式)，则该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模式的邻块的位置及其遍历顺序也是预先定义好的，且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候选运动矢量列表中是否已经存在相同的运动信息，如果存在相同的运动信息，则不会将该运动信息加入列表中。可以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，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。
在视频编码标准中，通常使用基于平动运动模型的块匹配进行运动估计，并且假设块中所有像素点的运动一致。但是，由于在现实世界中，运动是多种多样的，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。对于它们的编码，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。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。
其中，本申请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。
4参数仿射运动模型如下公式(2)所示：
Figure PCTCN2019127669-appb-000002
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 PCTCN2019127669-appb-000003
6参数仿射运动模型如下公式(4)所示：
Figure PCTCN2019127669-appb-000004
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 PCTCN2019127669-appb-000005
采用仿射运动模型进行预测的编码块称为仿射编码块。
通常的，可以使用基于仿射运动模型的先进运动矢量预测(Advanced Motion Vector Prediction，AMVP)模式或者基于仿射运动模型的融合(Merge)模式，获得仿射编码块的控制点的运动信息。
具体的，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。
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，推导出用于Merge模式下的当前块的控制点运动矢量，或者推导出用于AMVP模式下的控制点的运动矢量预测值。需要说明的是，A1->B1->B0->A0->B2仅作为一种示例，其它组合的顺序也适用于本申请。另外，相邻位置块不限于A1、B1、B0、A0和B2。
相邻位置块可以为一个像素点，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。
下面以A1为例描述确定过程，其他情况以此类推：
如图7所示，若A1所在的编码块为4参数仿射编码块，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)；利用公式(6)计算获得当前仿射编码块左上顶点(x0,y0)的运动矢量(vx0,vy0)，利用公式(7)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 PCTCN2019127669-appb-000006
Figure PCTCN2019127669-appb-000007
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，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)；利用公式(8)计算获得当前块左上顶点(x0,y0)的运动矢量(vx0,vy0)，利用公式(9)计算获得当前块右上顶点(x1,y1)的运动矢量(vx1,vy1)、利用公式(10)计算获得当前块左下顶点(x2,y2)的运动矢量(vx2,vy2)。
Figure PCTCN2019127669-appb-000008
Figure PCTCN2019127669-appb-000009
Figure PCTCN2019127669-appb-000010
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申请，本申请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申请，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。
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。以图8所示为例对构造的控制点运动矢量预测方法进行描述。需要说明的是，图8仅作为一种示例。
如图8所示，利用左上顶点相邻已编码块A2，B2和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和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，参见如下公式(11A)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}    (11A)
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。
如图8所示，利用左上顶点相邻已编码块A2，B2和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和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、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，参见如下公式(11B)、(11C)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}(11B)
{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}(11C)；
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申请，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申请，此处不做赘述。
5)基于仿射运动模型的先进运动矢量预测模式(Affine AMVP mode)：
(1)构建候选运动矢量列表
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。在本申请实施例中，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)，每个控制点的运动矢量预测值包括2个(4参数仿射运动模型)控制点的运动矢量或者包括3个(6参数仿射运动模型)控制点的运动矢量。
可选的，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。
(2)确定最优的控制点运动矢量预测值
在编码端，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)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个控制点的运动矢量预测值。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编码入码流发送给解码器。
在解码端，解析索引号，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)。
(3)确定控制点的运动矢量
在编码端，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)。并将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)传递到解码端。
在解码端，解析控制点运动矢量差值，与控制点运动矢量预测值相加，得到控制 点运动矢量。
6)基于仿射运动模型的仿射融合模式(Affine Merge mode)：
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)。
可选的，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。
在编码端，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)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器。
在解码端，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)。
7)自适应运动矢量精度(Adaptive motion vector resolution，AMVR)模式：
在AMVR模式下，运动矢量差分(Motion vector differences，MVD)可以编码为1/16精度、1/4精度或者整像素精度。可以以AMVR索引(index)值来表示不同的精度，例如index＝0，对应的MVD精度为1/16，index＝1，对应的MVD精度为1/4，index＝2，对应的MVD精度为整像素精度。可选的，AMVR index和精度值的对应关系还可以是其他方式，如index＝0，对应的MVD精度为1/4，本申请对此不予赘述。在下文中，以index＝0，对应的MVD精度为1/16，index＝1，对应的MVD精度为1/4，index＝2，对应的MVD精度为整像素精度为例进行说明。
另外，可以用MV精度值(precision)和其所占比特深度(bit-depth)来联合表示MV的可取值范围。如果MV精度为R，所占比特深度为Sbit，则MV的最大值maxMV＝R*2 s-1-1，最小值为minMV＝-R*2 s-1。举例如下：
若MV精度为1/16，所占比特深度为16bit，MV可表示的范围为(-2 11，2 11-1)。
若MV精度为1/4，所占比特深度为16bit，MV可表示的范围为(-2 13，2 13-1)。
若MV精度为1/16，所占比特深度为18bit，MV可表示的范围为(-2 13，2 13-1)。
如果当前块使用AMVR模式，则CPMVD的精度可以为1/16，CPMVD的比特深度为16bit，或者，CPMVD的精度可以为1/4，CPMVD的比特深度为16bit，或者，CPMVD的精度可以为整像素精度，CPMVD的比特深度为16bit。
因此，在运动补偿和运动信息存储过程中的运动信息的精度可能不统一。针对仿射变换块运动补偿和运动信息(后续编码流程的运动信息)存储的过程，本申请提出了一种仿射编码块的运动信息的存储和运动补偿中精度变换方法。如果运动补偿与存储的运动信息精度相同，则采用相同的运动矢量精度；如果运动补偿与存储的运动信息精度不同，则将运动补偿的运动矢量精度量化为存储的运动矢量精度进行存储。
下面结合附图对本申请实施例进行描述。图9为本申请实施例提供的一种帧间预测的方法的流程图。假设待处理图像块为当前仿射编码块，如图9所示，该方法可以 包括：
S901、确定当前仿射编码块的预测模式为基于仿射运动模型的AMVP模式。
确定当前仿射编码块的帧间预测模式的方法可以通过解析语法元素得到，具体确定方法本申请不做具体限定。如果确定当前仿射编码块的帧间预测模式为基于仿射运动模型的AMVP模式，则执行以下步骤。
S902、获得当前仿射编码块的控制点的运动矢量。
当前仿射编码块的控制点的运动信息的获得方法可参照前述“基于仿射运动模型的AMVP模式”中所述的获取当前仿射编码块的控制点的运动信息的阐述，不予赘述。
例如，在解码端，解析码流可以得到控制点的运动矢量差值(CPMVD)和控制点的运动矢量的预测值的索引，根据控制点的运动矢量的预测值的索引从控制点运动矢量预测值候选列表确定控制点的运动矢量预测值(CPMVP)。例如，CPMVP可以通过获取存储单元中相邻已编码块的运动矢量得到，将CPMVD与CPMVP相加，得到控制点的运动矢量(CPMV)。
但是，为了节省存储空间，通常控制点运动矢量预测值候选列表是以低精度存储的，例如，CPMVP的精度可以为1/4像素精度，CPMVP的比特深度可以为16bit。
如果当前仿射编码块使用AMVR模式，则CPMVD的精度可以为1/16像素精度，且CPMVD的比特深度可以为16bit；或者，CPMVD的精度可以为1/4像素精度，且CPMVD的比特深度可以为16bit；或者，CPMVD的精度可以为整像素精度，且CPMVD的比特深度可以为16bit。
如果仍然以低精度的CPMVP和CPMVD确定CPMV，当前仿射编码块的帧间预测准确率较低。因此，可以通过提高CPMVP的精度和CPMVD的精度，确定CPMV，从而提高当前仿射编码块的帧间预测准确率。下面详细介绍如何通过提高CPMVP的精度和CPMVD的精度，确定CPMV。
首先，比较CPMVD的精度和预设的第一运动矢量精度，以及比较CPMVP的精度和第一运动矢量精度。当CPMVD的精度不等于第一运动矢量精度，CPMVP的精度等于第一运动矢量精度时，可以根据CPMVD和第一偏移值，获得当前仿射编码块的控制点的运动矢量。当CPMVD的精度等于第一运动矢量精度，CPMVP的精度不等于第一运动矢量精度时，可以根据CPMVP和第二偏移值，获得当前仿射编码块的控制点的运动矢量。当CPMVD的精度不等于第一运动矢量精度，以及CPMVP的精度不等于第一运动矢量精度时，可以根据CPMVD、第一偏移值、CPMVP和第二偏移值，获得当前仿射编码块的控制点的运动矢量。
示例的，可以采用如下公式(12)，获得当前仿射编码块的控制点的运动矢量。
CPMV＝CPMVD’+CPMVP’       (12)
当CPMVD的精度不等于第一运动矢量精度时，CPMVD’＝CPMVD<<mvrShift1。
当CPMVD的精度等于第一运动矢量精度时，CPMVD’＝CPMVD。可以理解的，CPMVD的精度无需调整。
当CPMVP的精度不等于第一运动矢量精度时，CPMVP’＝CPMVP<<mvrShift2。
当CPMVP的精度等于第一运动矢量精度时，CPMVP’＝CPMVP。可以理解的，CPMVP的精度无需调整。
其中，CPMV表示控制点的运动矢量，mvrShift1表示第一偏移值，mvrShift2表示第二偏移值。
需要说明的是，第一偏移值可以是根据第一运动矢量精度和CPMVD的精度确定的。例如，第一运动矢量精度为1/2 m，CPMVD的精度为1/2 n，第一偏移值可以为m减n的差值。同理，第二偏移值可以是根据第一运动矢量精度和CPMVP的精度确定的。例如，第一运动矢量精度为1/2 m，CPMVP的精度为1/2 n，第二偏移值可以为m减n的差值。
在第一种可行的实施方式中，当第一运动矢量精度为1/16(1/2 4)像素精度且CPMVD的精度为1/16像素精度时，第一偏移值等于0；当第一运动矢量精度为1/16像素精度且CPMVD的精度为1/4(1/2 2)像素精度时，第一偏移值等于2；当第一运动矢量精度为1/16像素精度且CPMVD的精度为整像素精度(1/2 0)时，第一偏移值等于4。
当第一运动矢量精度为1/16像素精度且CPMVP的精度为1/16像素精度时，第二偏移值等于0；当第一运动矢量精度为1/16像素精度且CPMVP的精度为1/4像素精度时，第二偏移值等于2；当第一运动矢量精度为1/16像素精度且CPMVP的精度为整像素精度时，第二偏移值等于4。
应理解，当第一偏移值等于0或者第二偏移值等于0时，在一种可行的实施方式中，并不进行偏移。
示例的，当第一运动矢量精度为1/16像素精度时，当前仿射编码块的控制点的运动矢量可以有以下取值。
若CPMVD的精度为1/16像素精度，CPMVP的精度为1/4像素精度，则第一偏移值的取值可以为0，第二偏移值的取值可以为2，当前仿射编码块的控制点的运动矢量为CPMV＝(CPMVD<<0)+(CPMVP<<2)。
若CPMVD的精度为1/4像素精度，CPMVP的精度为1/4像素精度，则第一偏移值的取值可以为2，第二偏移值的取值可以为2，当前仿射编码块的控制点的运动矢量为CPMV＝(CPMVD<<2)+(CPMVP<<2)。
若CPMVD的精度为整像素精度，CPMVP的精度为1/4像素精度，则第一偏移值的取值可以为4，第二偏移值的取值可以为2，当前仿射编码块的控制点的运动矢量为CPMV＝(CPMVD<<4)+(CPMVP<<2)。
在第二种可行的实施方式中，当第一运动矢量精度为1/32(1/2 5)像素精度且CPMVD的精度为1/16(1/2 4)像素精度时，第一偏移值等于1；当第一运动矢量精度为1/32像素精度且CPMVD的精度为1/4(1/2 2)像素精度时，第一偏移值等于3；当第一运动矢量精度为1/32像素精度且CPMVD的精度为整像素精度(1/2 0)时，第一偏移值等于5。
当第一运动矢量精度为1/32像素精度且CPMVP的精度为1/16像素精度时，第二偏移值等于1；当第一运动矢量精度为1/32像素精度且CPMVP的精度为1/4像素精度时，第二偏移值等于3；当第一运动矢量精度为1/32像素精度且CPMVP的精度为整像素精度时，第二偏移值等于5。
示例的，当第一运动矢量精度为1/32像素精度时，当前仿射编码块的控制点的运 动矢量可以有以下取值。
若CPMVD的精度为1/16像素精度，CPMVP的精度为1/4像素精度，则第一偏移值的取值可以为1，第二偏移值的取值可以为3，当前仿射编码块的控制点的运动矢量为CPMV＝(CPMVD<<1)+(CPMVP<<3)。
若CPMVD的精度为1/4像素精度，CPMVP的精度为1/4像素精度，则第一偏移值的取值可以为3，第二偏移值的取值可以为3，当前仿射编码块的控制点的运动矢量为CPMV＝(CPMVD<<3)+(CPMVP<<3)。
若CPMVD的精度为整像素精度，CPMVP的精度为1/4像素精度，则第一偏移值的取值可以为5，第二偏移值的取值可以为3，当前仿射编码块的控制点的运动矢量为CPMV＝(CPMVD<<5)+(CPMVP<<3)。
在第三种可行的实施方式中，当第一运动矢量精度为1/64(1/2 6)像素精度且CPMVD的精度为1/16(1/2 4)像素精度时，第一偏移值等于2；当第一运动矢量精度为1/64像素精度且CPMVD的精度为1/4(1/2 2)像素精度时，第一偏移值等于4；当第一运动矢量精度为1/64像素精度且CPMVD的精度为整像素精度(1/2 0)时，第一偏移值等于6。
当第一运动矢量精度为1/64像素精度且CPMVP的精度为1/16像素精度时，第二偏移值等于2；当第一运动矢量精度为1/64像素精度且CPMVP的精度为1/4像素精度时，第二偏移值等于4；当第一运动矢量精度为1/64像素精度且CPMVP的精度为整像素精度时，第二偏移值等于6。
示例的，当第一运动矢量精度为1/64像素精度时，当前仿射编码块的控制点的运动矢量可以有以下取值。
若CPMVD的精度为1/16像素精度，CPMVP的精度为1/4像素精度，则第一偏移值的取值可以为2，第二偏移值的取值可以为4，当前仿射编码块的控制点的运动矢量为CPMV＝(CPMVD<<2)+(CPMVP<<4)。
若CPMVD的精度为1/4像素精度，CPMVP的精度为1/4像素精度，则第一偏移值的取值可以为4，第二偏移值的取值可以为4，当前仿射编码块的控制点的运动矢量为CPMV＝(CPMVD<<4)+(CPMVP<<4)。
若CPMVD的精度为整像素精度，CPMVP的精度为1/4像素精度，则第一偏移值的取值可以为6，第二偏移值的取值可以为4，当前仿射编码块的控制点的运动矢量为CPMV＝(CPMVD<<6)+(CPMVP<<4)。
进一步的，还可以对控制点的运动矢量进行钳位以使控制点的运动矢量的比特深度等于第一运动矢量比特深度。
例如，比较控制点的运动矢量的比特深度和第一运动矢量比特深度，当控制点的运动矢量的比特深度大于第一运动矢量比特深度时，对控制点的运动矢量进行钳位以使控制点的运动矢量的比特深度等于第一运动矢量比特深度。
示例的，可以采用如下公式(13)，对控制点的运动矢量进行钳位以使控制点的运动矢量的比特深度等于第一运动矢量比特深度。
vx＝Clip3(-2 bitDepth-1,2 bitDepth-1-1,vx)
vy＝Clip3(-2 bitDepth-1,2 bitDepth-1-1,vy)    (13)
其中，(vx,vy)为当前仿射编码块的控制点的运动矢量，Clip3的定义为，表示将z的值钳位到区间[x,y]之间：
Figure PCTCN2019127669-appb-000011
例如，若第一运动矢量精度为1/16像素精度，第一运动矢量比特深度为18bit，MV可表示的范围为(-2 13，2 13-1)。为了使得控制点的运动矢量的取值范围为(-2 13，2 13-1)，可以将控制点的运动矢量的比特深度进行钳位，即将18bit代入公式(13)，以使控制点的运动矢量的比特深度等于第一运动矢量比特深度。
S903、根据控制点的运动矢量，推导当前仿射编码块中每个运动补偿单元的运动矢量。
根据控制点的运动信息，采用仿射变换模型，确定当前仿射编码块中每一个运动补偿单元的运动信息。
对于当前仿射编码块的每一个运动补偿单元，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)、左上顶点(0,0)，右上顶点(M-1,0)，或其他位置的像素点。以下以运动补偿单元中心点为例说明。
运动补偿单元的尺寸MxN为编解码共同约定的采用相同规则确定的尺寸，可以固定地设置为4x4、8x8等，也可以根据控制点运动矢量差异、运动矢量精度和控制点之间的距离进行确定。
需要说明的是，当前仿射编码块的运动补偿单元的尺寸可以通过其他方法确定，在本申请不予赘述。
运动补偿单元中心点相对于当前仿射编码块左上顶点像素的坐标可以使用公式(14)计算得到。
Figure PCTCN2019127669-appb-000012
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编码块左上顶点像素的坐标。再将(x (i,j),y (i,j))代入公式(15)，获得每个运动补偿单元中心点的运动信息，作为该运动补偿单元内所有像素点的运动信息(vx (i,j),vy (i,j))。
Figure PCTCN2019127669-appb-000013
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：
log2W＝Log2(W)
log2H＝Log2(H)
mvScaleHor＝vx0<<7
mvScaleVer＝vy0<<7
dHorX＝(vx1–vx0)<<(7–log2W)
dVerX＝(vy1–vy0)<<(7–log2W)
若当前仿射解码块为6参数仿射解码块，则令：
dHorY＝(vx2–vx0)<<(7–log2H)
dVerY＝(vy2–vy0)<<(7–log2H)
若当前仿射解码块为4参数仿射解码块，则令：
dHorY＝–dVerX
dVerY＝dHorX
接着，运动补偿的运动矢量可以按照以下公式计算：
vx＝Round(mvScaleHor+dHorX*x+dHorY*y)
vy＝Round(mvScaleVer+dVerX*x+dVerY*y)
其中Round函数的操作如下，对于任意输入K和mvShift，其输出K通过以下方式获得：
offset＝1<<(mvShift–1)
K＝K>＝0？(K+offset)>>mvShift:–((–K+offset)>>mvShift)
接着对得到的运动矢量(vx,vy)进行钳位，使得其不超过18bit的动态范围。
例如：当CPMV的精度为1/4像素精度时，可以将mvShift设置为5，得出运动补偿单元的运动矢量的精度为1/16像素精度。当CPMV的精度为1/16像素精度时，可以将mvShift设置为7，得出运动补偿单元的运动矢量的精度为1/16像素精度。当CPMV的精度为1/16像素精度时，可以将mvShift设置为9，得出运动补偿单元的运动矢量的精度为1/4像素精度。
例如：当控制点的运动矢量的精度为1/16像素精度，控制点的运动矢量的比特深度为18bit时，可以将mvShift设置为7，则运动补偿单元的运动矢量的精度为1/16像素精度，运动补偿单元的运动矢量的比特深度为18bit。
S904、基于每个运动补偿单元的运动矢量，获取当前仿射编码块的重建块。
例如，基于每个运动补偿单元的运动矢量，分别进行运动补偿，以获得当前仿射编码块的预测块，对于当前仿射编码块的每一个运动补偿单元，采用S903得到的运动信息，进行运动补偿预测，得到每个运动补偿单元的预测值。然后，基于预测块和每个运动补偿单元的运动矢量，获得当前仿射编码块的重建块。
可选的，将预测块和当前仿射编码块的残差块相加，获得当前仿射编码块的重建块；或者，根据每个运动补偿单元的运动矢量，对预测块进行更新，将更新后的预测块和当前仿射编码块的残差块相加，获得当前仿射编码块的重建块；或者，将预测块和当前仿射编码块的残差块相加，获得当前仿射编码块的重建块，基于每个运动补偿单元的运动矢量，对重建块进行滤波处理；或者，将预测块和当前仿射编码块的残差块相加，获得当前仿射编码块的重建块，将每个运动补偿单元的运动矢量和重建块作为后续当前仿射编码块的预测信息。
如果根据S903得出运动补偿单元的运动矢量的精度为存储单元的运动矢量的精度，例如1/4像素精度，可以无需执行S905。
如果根据S903得出运动补偿单元的运动矢量的精度不是存储单元的运动矢量的精度，例如1/4像素精度，需执行S905。
S905、处理运动补偿单元的运动矢量精度以满足预设的第二运动矢量精度，和/或，处理运动补偿单元的运动矢量比特深度以满足预设的第二运动矢量精度比特深度。
在后续解码流程中，如去块效应滤波器、重叠块运动补偿、后续编码块的运动信息的推导等，需要利用当前仿射编码块的运动信息。因此需要将S903得到的运动补偿单元的运动信息进行存储。
通常运动信息存储单元的尺寸为4x4，则对于运动补偿单元内的每一个4x4存储单元，将其运动信息设置为该运动补偿单元的运动信息。
需要说明的是，若运动补偿单元的运动矢量精度与存储单元的运动矢量精度不同，需要将运动补偿单元的运动矢量量化到存储单元的运动矢量精度进行存储。举例说明如下：
可以采用如下公式(16)，获得处理后的运动补偿单元的运动矢量。
MCUMV’＝(MCUMV>>mvrShift3)     (16)
其中，MCUMV’表示处理后的运动补偿单元的运动矢量，MCUMV表示处理前的运动补偿单元的运动矢量，mvrShift3表示第三偏移值。
需要说明的是，第三偏移值可以是根据第二运动矢量精度和MCUMV的精度确定的。例如，第二运动矢量精度为1/2 k，MCUMV的精度为1/2 n，第三偏移值可以为n减k的差值。
在第一种可行的实施方式中，当第二运动矢量精度为1/4(1/2 2)像素精度且MCUMV的精度为1/16(1/2 4)像素精度时，第三偏移值等于2，处理后的运动补偿单元的运动矢量MCUMV’＝(MCUMV>>2)。
在第二种可行的实施方式中，当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/32(1/2 5)像素精度时，第三偏移值等于3，处理后的运动补偿单元的运动矢量MCUMV’＝(MCUMV>>3)。
在第三种可行的实施方式中，当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/64(1/2 6)像素精度时，第三偏移值等于4，处理后的运动补偿单元的运动矢量MCUMV’＝(MCUMV>>4)。
特别的，当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/4像素精度时，第三偏移值等于0，处理后的运动补偿单元的运动矢量MCUMV’＝MCUMV。可理解的，运动补偿单元的运动矢量无需进行像素精度降低的处理。
可选的，也可以直接通过公式(15)推导得到处理后的运动补偿单元的运动矢量精度满足第二运动矢量精度；也可以直接将S903得到的运动补偿单元的运动矢量精度进行量化，以使处理后的运动补偿单元的运动矢量满足第二运动矢量精度，量化的方法如S903中的round函数，例如，运动补偿单元的运动矢量精度为1/16像素精度，处理后的运动补偿单元的运动矢量精度为1/4像素精度，mvShift可以设置为2。
进一步的，还可以将处理后的运动补偿单元的运动矢量的比特深度进行钳位以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。
例如，当处理后的运动补偿单元的运动矢量的比特深度大于第二运动矢量比特深度时，对处理后的运动补偿单元的运动矢量进行钳位以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。具体的可以参考公式(13)的阐述， 不予赘述。
例如，若第二运动矢量精度为1/4像素精度，第二运动矢量比特深度为16bit，MV可表示的范围为(-2 11，2 11-1)。为了使得处理后的运动补偿单元的运动矢量的取值范围为(-2 11，2 11-1)，可以将处理后的运动补偿单元的运动矢量的比特深度进行钳位，即将16bit代入公式(13)，以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。
需要说明的是，第二运动矢量精度可以是存储单元的运动矢量精度。上述CPMVP的精度可以与存储单元的运动矢量精度相同。第二运动矢量比特深度可以是存储单元的运动矢量比特深度。CPMVP的比特深度可以与存储单元的比特深度相同。
S906、存储处理后的运动补偿单元的运动矢量。
需要说明的是，本申请实施例提供的帧间预测的方法步骤的先后顺序可以进行适当调整，步骤也可以根据情况进行相应增减，示例的，如S904可以与S905和S906之间的前后顺序可以互换，即可以先处理运动补偿单元的运动矢量精度以满足预设的第二运动矢量精度，和/或，处理运动补偿单元的运动矢量比特深度以满足预设的第二运动矢量精度比特深度，并存储处理后的运动补偿单元的运动矢量，再基于每个运动补偿单元的运动矢量，获取当前仿射编码块的重建块。任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化的方法，都应涵盖在本申请的保护范围之内，因此不再赘述。
本申请实施例一提出了一种仿射AMVP模式下的精度变化过程，通过提高控制点的运动矢量的精度和比特深度，进行运动补偿，可以有效地提高使用仿射运动模型的编码块的帧间预测准确率。
图10为本申请实施例提供的一种帧间预测的方法的流程图。假设待处理图像块为当前仿射编码块，如图10所示，该方法可以包括：
S1001、确定当前仿射编码块的预测模式为基于仿射运动模型的Merge模式。
确定当前仿射编码块的帧间预测模式的方法可以通过解析语法元素得到，具体确定方法本申请不做具体限定。如果确定当前仿射编码块的帧间预测模式为基于仿射运动模型的Merge模式，则执行以下步骤。
S1002、获得当前仿射编码块的控制点的运动矢量。
当前仿射编码块的控制点的运动信息的获得方法可参照前述“仿射融合模式(Affine Merge mode)”中所述的获取当前仿射编码块的控制点的运动信息的阐述，不予赘述。
S1003、调整控制点的运动矢量以满足预设的第一运动矢量精度和/或第一运动矢量比特深度。
控制点的运动矢量可以通过继承性的运动矢量预测方法或构造性的运动矢量预测方法得到，则控制点的运动矢量的精度和控制点的运动矢量的比特深度可以根据当前仿射编码块的相邻仿射单元得到。相邻块的运动矢量精度和比特深度可以通过读取存储单元的运动信息得到。为了节省存储空间，存储单元的运动信息以低精度存储的。例如，存储单元的运动矢量的精度为1/4像素精度，存储单元的运动矢量的比特深度为16bit。控制点的运动矢量的精度为1/4像素精度，控制点的运动矢量的比特深度为 16bit。
如果仍然以低精度的CPMV进行预测，当前仿射编码块的帧间预测准确率较低，因此，可以通过提高CPMV的精度，提高当前仿射编码块的帧间预测准确率。下面详细介绍如何通过提高CPMV的精度。
比较控制点的运动矢量的精度和预设的第一运动矢量精度，当控制点的运动矢量的精度不等于第一运动矢量精度时，可以根据控制点的运动矢量和第一偏移值调整控制点的运动矢量，获得调整后的控制点的运动矢量，以使调整后的控制点的运动矢量满足第一运动矢量精度。
方式一，可以采用如下公式(17)，获得调整后的控制点的运动矢量。
CPMV’＝CPMV<<mvrShift1     (17)
其中，CPMV表示控制点的运动矢量，CPMV’表示调整后的控制点的运动矢量，mvrShift1表示第一偏移值。
需要说明的是，第一偏移值可以是根据第一运动矢量精度和CPMV的精度确定的。例如，第一运动矢量精度为1/2 m，CPMV的精度为1/2 n，第一偏移值可以为m减n的差值。
在第一种可行的实施方式中，当第一运动矢量精度为1/16(1/2 4)像素精度且控制点的运动矢量的精度为1/16像素精度时，第一偏移值等于0；当第一运动矢量精度为1/16像素精度且控制点的运动矢量的精度为1/4(1/2 2)像素精度时，第一偏移值等于2；当第一运动矢量精度为1/16像素精度且控制点的运动矢量的精度为整像素精度(1/2 0)时，第一偏移值等于4。
应理解，当第一偏移值等于0时，在一种可行的实施方式中，并不进行偏移。
示例的，当第一运动矢量精度为1/16像素精度时，当前仿射编码块的调整后的控制点的运动矢量可以有以下取值。
若控制点的运动矢量的精度为1/16像素精度，则第一偏移值的取值可以为0，当前仿射编码块的调整后的控制点的运动矢量为CPMV’＝CPMV。可以理解的，当前仿射编码块的控制点的运动矢量可以无需调整。
若控制点的运动矢量的精度为1/4像素精度，则第一偏移值的取值可以为2，当前仿射编码块的调整后的控制点的运动矢量为CPMV’＝CPMV<<2。
若控制点的运动矢量的精度为整像素精度，则第一偏移值的取值可以为4，当前仿射编码块的调整后的控制点的运动矢量为CPMV’＝CPMV<<4。
在第二种可行的实施方式中，当第一运动矢量精度为1/32(1/2 5)像素精度且控制点的运动矢量的精度为1/16(1/2 4)像素精度时，第一偏移值等于1；当第一运动矢量精度为1/32像素精度且控制点的运动矢量的精度为1/4(1/2 2)像素精度时，第一偏移值等于3；当第一运动矢量精度为1/32像素精度且控制点的运动矢量的精度为整像素精度(1/2 0)时，第一偏移值等于5。
示例的，当第一运动矢量精度为1/32像素精度时，当前仿射编码块的调整后的控制点的运动矢量可以有以下取值。
若控制点的运动矢量的精度为1/16像素精度，则第一偏移值的取值可以为1，当前仿射编码块的调整后的控制点的运动矢量为CPMV’＝CPMV<<1。可以理解的，当前 仿射编码块的控制点的运动矢量可以无需调整。
若控制点的运动矢量的精度为1/4像素精度，则第一偏移值的取值可以为3，当前仿射编码块的调整后的控制点的运动矢量为CPMV’＝CPMV<<3。
若控制点的运动矢量的精度为整像素精度，则第一偏移值的取值可以为5，当前仿射编码块的调整后的控制点的运动矢量为CPMV’＝CPMV<<5。
在第三种可行的实施方式中，当第一运动矢量精度为1/64(1/2 6)像素精度且控制点的运动矢量的精度为1/16(1/2 4)像素精度时，第一偏移值等于2；当第一运动矢量精度为1/64像素精度且控制点的运动矢量的精度为1/4(1/2 2)像素精度时，第一偏移值等于4；当第一运动矢量精度为1/64像素精度且控制点的运动矢量的精度为整像素精度(1/2 0)时，第一偏移值等于6。
示例的，当第一运动矢量精度为1/64像素精度时，当前仿射编码块的调整后的控制点的运动矢量可以有以下取值。
若控制点的运动矢量的精度为1/16像素精度，则第一偏移值的取值可以为2，当前仿射编码块的调整后的控制点的运动矢量为CPMV’＝CPMV<<2。可以理解的，当前仿射编码块的控制点的运动矢量可以无需调整。
若控制点的运动矢量的精度为1/4像素精度，则第一偏移值的取值可以为4，当前仿射编码块的调整后的控制点的运动矢量为CPMV’＝CPMV<<4。
若控制点的运动矢量的精度为整像素精度，则第一偏移值的取值可以为6，当前仿射编码块的调整后的控制点的运动矢量为CPMV’＝CPMV<<6。
方式二，若控制点的运动矢量是通过继承性的运动矢量预测方法得到，即待处理图像块的已处理相邻图像块的预测模式为基于仿射运动模型的预测模式，当待处理图像块的控制点的运动矢量是基于已处理相邻图像块的控制点的运动矢量进行推导获得时，调整后的控制点的运动矢量通过如下公式获得：
vx0＝K1>＝0？(K1+offset)>>mvShift:–((–K1+offset)>>mvShift)，
vy0＝K2>＝0？(K2+offset)>>mvShift:–((–K2+offset)>>mvShift)，
vx1＝K3>＝0？(K3+offset)>>mvShift:–((–K3+offset)>>mvShift)，
vy1＝K4>＝0？(K4+offset)>>mvShift:–((–K4+offset)>>mvShift)，
vx2＝K5>＝0？(K5+offset)>>mvShift:–((–K5+offset)>>mvShift)，
vy2＝K6>＝0？(K6+offset)>>mvShift:–((–K6+offset)>>mvShift)，
其中，
K1＝mvScaleHor+dHorX*(x0–x4–M/2)+dHorY*(y0–y4–N/2)，
K2＝mvScaleVer+dVerX*(x0–x4–M/2)+dVerY*(y0–y4–N/2)，
K3＝mvScaleHor+dHorX*(x1–x4–M/2)+dHorY*(y1–y4–N/2)，
K4＝mvScaleVer+dVerX*(x1–x4–M/2)+dVerY*(y1–y4–N/2)，
K5＝mvScaleHor+dHorX*(x2–x4–M/2)+dHorY*(y2–y4–N/2)，
K6＝mvScaleVer+dVerX*(x2–x4–M/2)+dVerY*(y2–y4–N/2)，
offset＝1<<(mvShift–1)，
mvScaleHor＝vx4<<7，
mvScaleVer＝vy4<<7，
dHorX＝(vx5–vx4)<<(7–log2(P))，
dVerX＝(vy5–vy4)<<(7–log2(Q))，
当已处理相邻图像块的仿射运动模型为6参数模型时，dHorY＝(vx6–vx4)<<(7–log2(P))，dVerY＝(vy6–vy4)<<(7–log2(Q))，
当已处理相邻图像块的仿射运动模型为4参数模型时，dHorY＝–dVerX，dVerY＝dHorX，
Log2()表示取2的对数的函数，<<表示左移位，>>表示右移位，P为已处理相邻图像块的宽度、Q为已处理相邻图像块的高度，
(vx0,vy0)、(vx1,vy1)和(vx2,vy2)分别表示待处理图像块的三个控制点的运动矢量的水平分量和竖直分量，即，(vx0,vy0)是待处理图像块的第一个控制点的运动矢量的水平分量和竖直分量，(vx1,vy1)是待处理图像块的第二个控制点的运动矢量的水平分量和竖直分量，(vx2,vy2)是待处理图像块的第三个控制点的运动矢量的水平分量和竖直分量，
(vx4,vy4)、(vx5,vy5)和(vx6,vy6)分别表示已处理相邻图像块的三个控制点的运动矢量的水平分量和竖直分量，即，(vx4,vy4)是已处理相邻图像块的第一个控制点的运动矢量的水平分量和竖直分量，(vx5,vy5)是已处理相邻图像块的第二个控制点的运动矢量的水平分量和竖直分量，(vx6,vy6)是已处理相邻图像块的第三个控制点的运动矢量的水平分量和竖直分量，
mvShift基于已处理相邻图像块的控制点的运动矢量精度确定。
需要说明的是，相邻图像块可以是指空间相邻的仿射编码块或时域相邻的仿射编码块。
当相邻仿射块存储的CPMV的精度为1/4像素精度时，通过将mvShift设置为5，得到待处理图像块的CPMV的精度为1/16像素精度。当相邻仿射块存储的CPMV的精度为1/4像素精度时，可以将mvShift设置为6，得到待处理图像块的CPMV的精度为1/32像素精度。当相邻仿射块存储的CPMV的精度为1/4像素精度时，可以将mvShift设置为7，得到待处理图像块的CPMV的精度为1/4像素精度。其中，相邻仿射块的CPMV的精度可以是指存储单元的存储的运动矢量精度。
需要说明的是，在一种可能的实现方式中，可以通过方式二调整控制点的运动矢量，即通过设置mvShift，使控制点的运动矢量满足预设的第一运动矢量精度。如果使用方式二仍然无法使控制点的运动矢量满足预设的第一运动矢量精度，可以再通过方式一调整控制点的运动矢量，使控制点的运动矢量满足预设的第一运动矢量精度。当然，也可以直接使用方式一调整控制点的运动矢量，使控制点的运动矢量满足预设的第一运动矢量精度。本申请实施例不予限定。
进一步的，还可以对调整后的控制点的运动矢量进行钳位以使调整后的控制点的运动矢量的比特深度等于第一运动矢量比特深度。
例如，比较调整后的控制点的运动矢量的比特深度和第一运动矢量比特深度，当调整后的控制点的运动矢量的比特深度大于第一运动矢量比特深度时，对调整后的控制点的运动矢量进行钳位以使调整后的控制点的运动矢量的比特深度等于第一运动矢量比特深度。具体的可以参考上述公式(13)的阐述，不予赘述。
例如，若第一运动矢量精度为1/16像素精度，第一运动矢量比特深度为18bit，MV可表示的范围为(-2 13，2 13-1)。为了使得调整后的控制点的运动矢量的取值范围为(-2 13，2 13-1)，可以将调整后的控制点的运动矢量的比特深度进行钳位，即将18bit代入公式(13)，以使调整后的控制点的运动矢量的比特深度等于第一运动矢量比特深度。
S1004、根据调整后的控制点的运动矢量，推导当前仿射编码块中每个运动补偿单元的运动矢量。
根据调整后的控制点的运动信息，采用仿射变换模型，确定当前仿射编码块中每一个运动补偿单元的运动信息。
对于当前仿射编码块的每一个运动补偿单元，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)、左上顶点(0,0)，右上顶点(M-1,0)，或其他位置的像素点。以下以运动补偿单元中心点为例说明。
运动补偿单元的尺寸MxN为编解码共同约定的采用相同规则确定的尺寸，可以固定地设置为4x4、8x8等，也可以根据控制点运动矢量差异、运动矢量精度和控制点之间的距离进行确定。
需要说明的是，当前仿射编码块的运动补偿单元的尺寸可以通过其他方法确定，在本申请不予赘述。
运动补偿单元中心点相对于当前仿射编码块左上顶点像素的坐标可以使用公式(14)计算得到。
Figure PCTCN2019127669-appb-000014
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编码块左上顶点像素的坐标。再将(x (i,j),y (i,j))代入公式(15)，获得每个运动补偿单元中心点的运动信息，作为该运动补偿单元内所有像素点的运动信息(vx (ij),vy (ij))。
Figure PCTCN2019127669-appb-000015
如果调整后的控制点的运动矢量的精度为1/16像素精度，调整后的控制点的运动矢量的比特深度为18bit，则运动补偿单元的运动矢量的精度为1/16像素精度，运动补偿单元的运动矢量的比特深度为18bit。
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：
log2W＝Log2(W)
log2H＝Log2(H)
mvScaleHor＝vx0<<7
mvScaleVer＝vy0<<7
dHorX＝(vx1–vx0)<<(7–log2W)
dVerX＝(vy1–vy0)<<(7–log2W)
若当前仿射解码块为6参数仿射解码块，则令：
dHorY＝(vx2–vx0)<<(7–log2H)
dVerY＝(vy2–vy0)<<(7–log2H)
若当前仿射解码块为4参数仿射解码块，则令：
dHorY＝–dVerX
dVerY＝dHorX
接着，运动补偿的运动矢量可以按照以下公式计算：
vx＝Round(mvScaleHor+dHorX*x+dHorY*y)
vy＝Round(mvScaleVer+dVerX*x+dVerY*y)
其中Round函数的操作如下，对于任意输入K和mvShift，其输出K通过以下方式获得：
offset＝1<<(mvShift–1)
K＝K>＝0？(K+offset)>>mvShift:–((–K+offset)>>mvShift)
接着对得到的运动矢量(vx,vy)进行钳位，使得其不超过18bit的动态范围。
例如，当调整后的控制点的运动矢量的精度为1/16像素精度时，可将mvShift设置为7，得出运动补偿单元的运动矢量的精度为1/16像素精度。当调整后的控制点的运动矢量的精度为1/16像素精度时，可以将mvShift设置为7，得出运动补偿单元的运动矢量的精度为1/16像素精度。当调整后的控制点的运动矢量的精度为1/16像素精度时，可以将mvShift设置为9，得出运动补偿单元的运动矢量的精度为1/4像素精度。
S1005、基于每个运动补偿单元的运动矢量，获取当前仿射编码块的重建块。
例如，基于每个运动补偿单元的运动矢量，分别进行运动补偿，以获得当前仿射编码块的预测块，对于当前仿射编码块的每一个运动补偿单元，采用S1003得到的运动信息，进行运动补偿预测，得到每个运动补偿单元的预测值。然后，基于预测块和每个运动补偿单元的运动矢量，获得当前仿射编码块的重建块。
可选的，将预测块和当前仿射编码块的残差块相加，获得当前仿射编码块的重建块；或者，根据每个运动补偿单元的运动矢量，对预测块进行更新，将更新后的预测块和当前仿射编码块的残差块相加，获得当前仿射编码块的重建块；或者，将预测块和当前仿射编码块的残差块相加，获得当前仿射编码块的重建块，基于每个运动补偿单元的运动矢量，对重建块进行滤波处理；或者，将预测块和当前仿射编码块的残差块相加，获得当前仿射编码块的重建块，将每个运动补偿单元的运动矢量和重建块作为后续当前仿射编码块的预测信息。
如果根据S1004得出运动补偿单元的运动矢量的精度为存储单元的运动矢量的精度，例如1/4像素精度，可以无需执行S1006。
如果根据S1004得出运动补偿单元的运动矢量的精度不是存储单元的运动矢量的精度，例如1/4像素精度，需执行S1006。
S1006、处理运动补偿单元的运动矢量精度以满足预设的第二运动矢量精度，和/或，处理运动补偿单元的运动矢量比特深度以满足预设的第二运动矢量精度比特深度。
在后续解码流程中，如去块效应滤波器、重叠块运动补偿、后续编码块的运动信 息的推导等，需要利用当前仿射编码块的运动信息。因此需要将S1004得到的运动补偿单元的运动信息进行存储。
通常运动信息存储单元的尺寸为4x4，则对于运动补偿单元内的每一个4x4存储单元，将其运动信息设置为该运动补偿单元的运动信息。
需要说明的是，若运动补偿单元的运动矢量精度与存储单元的运动矢量精度不同，需要将运动补偿单元的运动矢量量化到存储单元的运动矢量精度进行存储。举例说明如下：
可以采用如下公式(18)，获得处理后的运动补偿单元的运动矢量。
MCUMV’＝(MCUMV>>mvrShift2)    (18)
其中，MCUMV’表示处理后的运动补偿单元的运动矢量，MCUMV表示处理前的运动补偿单元的运动矢量，mvrShift2表示第二偏移值。
需要说明的是，第二偏移值可以是根据第二运动矢量精度和MCUMV的精度确定的。例如，第二运动矢量精度为1/2 k，MCUMV的精度为1/2 n，第二偏移值可以为n减k的差值。
在第一种可行的实施方式中，当第二运动矢量精度为1/4(1/2 2)像素精度且MCUMV的精度为1/16(1/2 4)像素精度时，第二偏移值等于2，处理后的运动补偿单元的运动矢量MCUMV’＝(MCUMV>>2)。
在第二种可行的实施方式中，当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/32(1/2 5)像素精度时，第二偏移值等于3，处理后的运动补偿单元的运动矢量MCUMV’＝(MCUMV>>3)。
在第三种可行的实施方式中，当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/64(1/2 6)像素精度时，第二偏移值等于4，处理后的运动补偿单元的运动矢量MCUMV’＝(MCUMV>>4)。
特别的，当第二运动矢量精度为1/4像素精度且MCUMV的精度为1/4像素精度时，第二偏移值等于0，处理后的运动补偿单元的运动矢量MCUMV’＝MCUMV。可理解的，运动补偿单元的运动矢量无需进行像素精度降低的处理。
进一步的，还可以将处理后的运动补偿单元的运动矢量的比特深度进行钳位以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。
例如，当处理后的运动补偿单元的运动矢量的比特深度大于第二运动矢量比特深度时，对处理后的运动补偿单元的运动矢量进行钳位以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。具体的可以参考公式(13)的阐述，不予赘述。
例如，若第二运动矢量精度为1/4像素精度，第二运动矢量比特深度为16bit，MV可表示的范围为(-2 11，2 11-1)。为了使得处理后的运动补偿单元的运动矢量的取值范围为(-2 11，2 11-1)，可以将处理后的运动补偿单元的运动矢量的比特深度进行钳位，即将16bit代入公式(13)，以使处理后的运动补偿单元的运动矢量的比特深度等于第二运动矢量比特深度。
S1007、存储处理后的运动补偿单元的运动矢量。
需要说明的是，本申请实施例提供的帧间预测的方法步骤的先后顺序可以进行适 当调整，步骤也可以根据情况进行相应增减，示例的，如S1005与S1006和S1007之间的前后顺序可以互换，即先处理运动补偿单元的运动矢量精度以满足预设的第二运动矢量精度，和/或，处理运动补偿单元的运动矢量比特深度以满足预设的第二运动矢量精度比特深度，并存储处理后的运动补偿单元的运动矢量，再基于每个运动补偿单元的运动矢量，获取当前仿射编码块的重建块。任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化的方法，都应涵盖在本申请的保护范围之内，因此不再赘述。
本申请实施例一提出了一种仿射AMVP模式下的精度变化过程，通过提高控制点的运动矢量的精度和比特深度，进行运动补偿，可以有效地提高使用仿射运动模型的编码块的帧间预测准确率。
本申请实施例提供一种帧间预测的装置，该装置可以为视频解码器，也可以为视频编码器，还可以为解码器。具体的，帧间预测的装置用于执行以上帧间预测的方法中的解码装置所执行的步骤。本申请实施例提供的帧间预测的装置可以包括相应步骤所对应的模块。
本申请实施例可以根据上述方法示例对帧间预测的装置进行功能模块的划分，例如，可以对应各个功能划分各个功能模块，也可以将两个或两个以上的功能集成在一个处理模块中。上述集成的模块既可以采用硬件的形式实现，也可以采用软件功能模块的形式实现。本申请实施例中对模块的划分是示意性的，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式。
在采用对应各个功能划分各个功能模块的情况下，图11示出上述实施例中所涉及的帧间预测的装置的一种可能的结构示意图。如图11所示，帧间预测的装置1100可以包括确定模块1101、获取模块1102、计算模块1103和重建模块1104。具体的，各模块功能如下：
确定模块1101，用于确定待处理图像块的预测模式为基于仿射运动模型的AMVP模式。
获取模块1102，用于获得待处理图像块的控制点的运动矢量，控制点的运动矢量满足预设的第一运动矢量精度和/或第一运动矢量比特深度。
计算模块1103，用于根据控制点的运动矢量，推导待处理图像块中每个运动补偿单元的运动矢量。
重建模块1104，用于基于每个运动补偿单元的运动矢量，获取待处理图像块的重建块。
其中，确定模块1101用于支持该帧间预测的装置1100执行上述实施例中的S901或S1001等，和/或用于本文所描述的技术的其它过程。获取模块1102用于支持该帧间预测的装置1100执行上述实施例中的S902或S1002等，和/或用于本文所描述的技术的其它过程。计算模块1103用于支持该帧间预测的装置1100执行上述实施例中的S903和S905或S1004等，和/或用于本文所描述的技术的其它过程。重建模块1104用于支持该帧间预测的装置1100执行上述实施例中的S904或S1005等，和/或用于本文所描述的技术的其它过程。
可选的，帧间预测的装置1100还可以包括调整模块1105，调整模块1105，用于 调整控制点的运动矢量以满足预设的第一运动矢量精度和/或第一运动矢量比特深度。其中，调整模块1105用于支持该帧间预测的装置1100执行上述实施例中的S1003和S1006等，和/或用于本文所描述的技术的其它过程。
进一步的，如图11所示，帧间预测的装置1100还可以包括存储模块1106，用于存储处理后的运动补偿单元的运动矢量。其中，存储模块1106用于支持该帧间预测的装置1100执行上述实施例中的S906和S1007等，和/或用于本文所描述的技术的其它过程。
其中，上述方法实施例涉及的各步骤的所有相关内容均可以援引到对应功能模块的功能描述，在此不再赘述。
虽然关于视频编码器及视频解码器已描述本申请的特定方面，但应理解，本申请的技术可通过许多其它视频编码和/或编码单元、处理器、处理单元、例如编码器/解码器(CODEC)的基于硬件的编码单元及类似者来应用。此外，应理解，仅作为可行的实施方式而提供关于图11所展示及描述的步骤。即，图11的可行的实施方式中所展示的步骤无需必定按图11中所展示的次序执行，且可执行更少、额外或替代步骤。
在采用集成的单元的情况下，图12为本申请实施例中的帧间预测的装置1200的一种示意性结构框图。具体的，帧间预测的装置1200包括：处理模块1201和耦合于所述处理模块的存储模块1202；所述处理模块1201用于执行图11所示的实施例以及各种可行的实施方式。
其中，处理模块1201可以是处理器或控制器，例如可以是中央处理器(Central Processing Unit，CPU)，通用处理器，数字信号处理器(Digital Signal Processor，DSP)，ASIC，FPGA或者其他可编程逻辑器件、晶体管逻辑器件、硬件部件或者其任意组合。其可以实现或执行结合本申请公开内容所描述的各种示例性的逻辑方框，模块和电路。所述处理器也可以是实现计算功能的组合，例如包含一个或多个微处理器组合，DSP和微处理器的组合等等。存储模块1202可以是存储器。
其中，上述方法实施例涉及的各场景的所有相关内容均可以援引到对应功能模块的功能描述，在此不再赘述。
上述帧间预测的装置1100和帧间预测的装置1200均可执行上述图9或图10所示的帧间预测的方法，帧间预测的装置1100和帧间预测的装置1200具体可以是视频解码装置或者其他具有视频编解码功能的设备。帧间预测的装置1100和帧间预测的装置1200可以用于在解码过程中进行图像预测。
本申请实施例提供一种帧间预测装置，该帧间预测装置可以为视频解码器，也可以为视频编码器，还可以为解码器。具体的，帧间预测装置用于执行以上帧间预测方法中的帧间预测装置所执行的步骤。本申请实施例提供的帧间预测装置可以包括相应步骤所对应的模块。
本申请实施例可以根据上述方法示例对帧间预测装置进行功能模块的划分，例如，可以对应各个功能划分各个功能模块，也可以将两个或两个以上的功能集成在一个处理模块中。上述集成的模块既可以采用硬件的形式实现，也可以采用软件功能模块的形式实现。本申请实施例中对模块的划分是示意性的，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式。
本申请还提供一种终端，该终端包括：一个或多个处理器、存储器、通信接口。该存储器、通信接口与一个或多个处理器耦合；存储器用于存储计算机程序代码，计算机程序代码包括指令，当一个或多个处理器执行指令时，终端执行本申请实施例的帧间预测的方法。
这里的终端可以是视频显示设备，智能手机，便携式电脑以及其它可以处理视频或者播放视频的设备。
本申请还提供一种视频解码器，包括非易失性存储介质，以及中央处理器，所述非易失性存储介质存储有可执行程序，所述中央处理器与所述非易失性存储介质连接，并执行所述可执行程序以实现本申请实施例的帧间预测的方法。
本申请还提供一种解码器，所述解码器包括本申请实施例中的帧间预测的装置。
本申请另一实施例还提供一种计算机可读存储介质，该计算机可读存储介质包括一个或多个程序代码，该一个或多个程序包括指令，当终端中的处理器在执行该程序代码时，该终端执行如图9或图10所示的帧间预测的方法。
在本申请的另一实施例中，还提供一种计算机程序产品，该计算机程序产品包括计算机执行指令，该计算机执行指令存储在计算机可读存储介质中；终端的至少一个处理器可以从计算机可读存储介质读取该计算机执行指令，至少一个处理器执行该计算机执行指令使得终端实施执行如图9或图10所示的帧间预测的方法。
在上述实施例中，可以全部或部分的通过软件，硬件，固件或者其任意组合来实现。当使用软件程序实现时，可以全部或部分地以计算机程序产品的形式出现。所述计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行所述计算机程序指令时，全部或部分地产生按照本申请实施例所述的流程或功能。
所述计算机可以是通用计算机、专用计算机、计算机网络、或者其他可编程装置。所述计算机指令可以存储在计算机可读存储介质中，或者从一个计算机可读存储介质向另一个计算机可读存储介质传输，例如，所述计算机指令可以从一个网站站点、计算机、服务器或数据中心通过有线(例如同轴电缆、光纤、数字用户线(DSL))或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心传输。所述计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包含一个或多个可用介质集成的服务器、数据中心等数据存储设备。该可用介质可以是磁性介质，(例如，软盘，硬盘、磁带)、光介质(例如，DVD)或者半导体介质(例如固态硬盘Solid State Disk(SSD))等。
此外，应理解，取决于可行的实施方式，本文中所描述的方法中的任一者的特定动作或事件可按不同序列执行，可经添加、合并或一起省去(例如，并非所有所描述的动作或事件为实践方法所必要的)。此外，在特定可行的实施方式中，动作或事件可(例如)经由多线程处理、中断处理或多个处理器来同时而非顺序地执行。另外，虽然出于清楚的目的将本申请的特定方面描述为通过单一模块或单元执行，但应理解，本申请的技术可通过与视频解码器相关联的单元或模块的组合执行。
在一个或多个可行的实施方式中，所描述的功能可以硬件、软件、固件或其任何组合来实施。如果以软件来实施，那么功能可作为一个或多个指令或代码而存储于计算机可读媒体上或经由计算机可读媒体来传输，且通过基于硬件的处理单元来执行。 计算机可读媒体可包含计算机可读存储媒体或通信媒体，计算机可读存储媒体对应于例如数据存储媒体的有形媒体，通信媒体包含促进计算机程序(例如)根据通信协议从一处传送到另一处的任何媒体。
以这个方式，计算机可读媒体示例性地可对应于(1)非暂时性的有形计算机可读存储媒体，或(2)例如信号或载波的通信媒体。数据存储媒体可为可由一个或多个计算机或一个或多个处理器存取以检索用于实施本申请中所描述的技术的指令、代码和/或数据结构的任何可用媒体。计算机程序产品可包含计算机可读媒体。
作为可行的实施方式而非限制，此计算机可读存储媒体可包括RAM、ROM、EEPROM、CD-ROM或其它光盘存储装置、磁盘存储装置或其它磁性存储装置、快闪存储器或可用于存储呈指令或数据结构的形式的所要代码且可由计算机存取的任何其它媒体。同样，任何连接可适当地称作计算机可读媒体。例如，如果使用同轴缆线、光纤缆线、双绞线、数字订户线(DSL)，或例如红外线、无线电及微波的无线技术而从网站、服务器或其它远端源传输指令，那么同轴缆线、光纤缆线、双绞线、DSL，或例如红外线、无线电及微波的无线技术包含于媒体的定义中。
然而，应理解，计算机可读存储媒体及数据存储媒体不包含连接、载波、信号或其它暂时性媒体，而替代地针对非暂时性有形存储媒体。如本文中所使用，磁盘及光盘包含紧密光盘(CD)、雷射光盘、光盘、数字多功能光盘(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，而光盘通过雷射以光学方式再现数据。以上各物的组合也应包含于计算机可读媒体的范围内。
可通过例如一个或多个数字信号处理器(DSP)、通用微处理器、专用集成电路(ASIC)、现场可编程门阵列(FPGA)或其它等效集成或离散逻辑电路的一个或多个处理器来执行指令。因此，如本文中所使用，术语“处理器”可指前述结构或适于实施本文中所描述的技术的任何其它结构中的任一者。另外，在一些方面中，可将本文所描述的功能性提供于经配置以用于编码及解码的专用硬件和/或软件模块内，或并入于组合式编码解码器中。同样，技术可完全实施于一个或多个电路或逻辑元件中。
本申请的技术可实施于广泛多种装置或设备中，包含无线手机、集成电路(IC)或IC的集合(例如，芯片组)。本申请中描述各种组件、模块或单元以强调经配置以执行所揭示的技术的装置的功能方面，但未必需要通过不同硬件单元实现。更确切来说，如前文所描述，各种单元可组合于编码解码器硬件单元中或由互操作的硬件单元(包含如前文所描述的一个或多个处理器)结合合适软件和/或固件的集合来提供。
以上所述，仅为本申请示例性的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到的变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应该以权利要求的保护范围为准。

Claims (76)

  1. 一种帧间预测的方法，其特征在于，包括：
    确定待处理图像块的预测模式为基于仿射运动模型的先进运动矢量预测AMVP模式；
    获得所述待处理图像块的控制点的运动矢量，所述控制点的运动矢量满足预设的第一运动矢量精度和/或第一运动矢量比特深度；
    根据所述控制点的运动矢量，推导所述待处理图像块中每个运动补偿单元的运动矢量；
    基于所述每个运动补偿单元的运动矢量，获取所述待处理图像块的重建块。
  2. 根据权利要求1所述的方法，其特征在于，所述获得所述待处理图像块的控制点的运动矢量，包括：
    获取所述控制点的运动矢量差值CPMVD和所述控制点的运动矢量的预测值CPMVP；
    当所述CPMVD的精度不等于所述第一运动矢量精度时，根据所述CPMVD和第一偏移值，获得所述待处理图像块的控制点的运动矢量；或者，
    当所述CPMVP的精度不等于所述第一运动矢量精度时，根据所述CPMVP和第二偏移值，获得所述待处理图像块的控制点的运动矢量。
  3. 根据权利要求2所述的方法，其特征在于，所述待处理图像块的控制点的运动矢量通过如下公式获得：
    CPMV＝CPMVD’+CPMVP’，
    其中，
    当所述CPMVD的精度不等于所述第一运动矢量精度时，CPMVD’＝CPMVD<<mvrShift1；
    当所述CPMVD的精度等于所述第一运动矢量精度时，CPMVD’＝CPMVD；
    当所述CPMVP的精度不等于所述第一运动矢量精度时，CPMVP’＝CPMVP<<mvrShift2；
    当所述CPMVP的精度等于所述第一运动矢量精度时，CPMVP’＝CPMVP；
    CPMV表示所述控制点的运动矢量，mvrShift1表示所述第一偏移值，mvrShift2表示所述第二偏移值。
  4. 根据权利要求3所述的方法，其特征在于，还包括：
    当所述控制点的运动矢量的比特深度大于所述第一运动矢量比特深度时，对所述控制点的运动矢量进行钳位以使所述控制点的运动矢量的比特深度等于所述第一运动矢量比特深度。
  5. 根据权利要求3所述的方法，其特征在于，还包括：
    对所述控制点的运动矢量进行钳位以使所述控制点的运动矢量的比特深度等于所述第一运动矢量比特深度。
  6. 根据权利要求2-5中任一项所述的方法，其特征在于，包括：
    当所述第一运动矢量精度为1/16像素精度且所述CPMVD的精度为1/16像素精度时，所述第一偏移值等于0；
    当所述第一运动矢量精度为1/16像素精度且所述CPMVD的精度为1/4像素精度时，所述第一偏移值等于2；
    当所述第一运动矢量精度为1/16像素精度且所述CPMVD的精度为整像素精度时，所述第一偏移值等于4；
    当所述第一运动矢量精度为1/16像素精度且所述CPMVP的精度为1/16像素精度时，所述第二偏移值等于0；
    当所述第一运动矢量精度为1/16像素精度且所述CPMVP的精度为1/4像素精度时，所述第二偏移值等于2；
    当所述第一运动矢量精度为1/16像素精度且所述CPMVP的精度为整像素精度时，所述第二偏移值等于4。
  7. 根据权利要求1-6中任一项所述的方法，其特征在于，所述方法还包括：
    处理所述运动补偿单元的运动矢量精度以满足预设的第二运动矢量精度，和/或，处理所述运动补偿单元的运动矢量比特深度以满足预设的第二运动矢量精度比特深度；
    存储所述处理后的运动补偿单元的运动矢量。
  8. 根据权利要求7所述的方法，其特征在于，所述处理后的运动补偿单元的运动矢量通过如下公式获得：
    MCUMV’＝(MCUMV>>mvrShift3)，
    其中，MCUMV’表示所述处理后的运动补偿单元的运动矢量，MCUMV表示所述处理前的运动补偿单元的运动矢量，mvrShift3表示第三偏移值。
  9. 根据权利要求8所述的方法，其特征在于，还包括：
    将所述处理后的运动补偿单元的运动矢量的比特深度进行钳位以使所述处理后的运动补偿单元的运动矢量的比特深度等于所述第二运动矢量比特深度。
  10. 根据权利要求8所述的方法，其特征在于，还包括：
    当所述处理后的运动补偿单元的运动矢量的比特深度大于所述第二运动矢量比特深度时，对所述处理后的运动补偿单元的运动矢量进行钳位以使所述处理后的运动补偿单元的运动矢量的比特深度等于所述第二运动矢量比特深度。
  11. 根据权利要求8-10任一项所述的方法，其特征在于，包括：
    当所述第二运动矢量精度为1/4像素精度且所述MCUMV的精度为1/16像素精度时，所述第三偏移值等于2；
    当所述第二运动矢量精度为1/4像素精度且所述MCUMV的精度为1/4像素精度时，所述第三偏移值等于0；
    当所述第二运动矢量精度为1/4像素精度且所述MCUMV的精度为1/32像素精度时，所述第三偏移值等于3。
  12. 根据权利要求1-11中任一项所述的方法，其特征在于，所述基于所述每个运动补偿单元的运动矢量，获取所述待处理图像块的重建块，包括：
    基于所述每个运动补偿单元的运动矢量，分别进行运动补偿，以获得所述待处理图像块的预测块；
    基于所述预测块和每个所述运动补偿单元的运动矢量，获得所述待处理图像块的重建块。
  13. 一种帧间预测的方法，其特征在于，包括：
    确定待处理图像块的预测模式为基于仿射运动模型的融合Merge预测模式；
    获得所述待处理图像块的控制点的运动矢量；
    调整所述控制点的运动矢量以满足预设的第一运动矢量精度和/或第一运动矢量比特深度；
    根据调整后的控制点的运动矢量，推导所述待处理图像块中每个运动补偿单元的运动矢量；
    基于所述每个运动补偿单元的运动矢量，获取所述待处理图像块的重建块。
  14. 根据权利要求13所述的方法，其特征在于，所述调整所述控制点的运动矢量，包括：
    当所述控制点的运动矢量的精度不等于所述第一运动矢量精度时，根据所述控制点的运动矢量和第一偏移值，获得所述调整后的控制点的运动矢量。
  15. 根据权利要求14所述的方法，其特征在于，所述调整后的控制点的运动矢量通过如下公式获得：
    CPMV’＝CPMV<<mvrShift1，其中，CPMV表示所述控制点的运动矢量，CPMV’表示所述调整后的控制点的运动矢量，mvrShift1表示所述第一偏移值。
  16. 根据权利要求14或15所述的方法，其特征在于，包括：
    当所述第一运动矢量精度为1/16像素精度且所述控制点的运动矢量的精度为1/16像素精度时，所述第一偏移值等于0；
    当所述第一运动矢量精度为1/16像素精度且所述控制点的运动矢量的精度为1/4像素精度时，所述第一偏移值等于2；
    当所述第一运动矢量精度为1/16像素精度且所述控制点的运动矢量的精度为整像素精度时，所述第一偏移值等于4。
  17. 根据权利要求13所述的方法，其特征在于，所述待处理图像块的已处理相邻图像块的预测模式为基于仿射运动模型的预测模式，当所述待处理图像块的控制点的运动矢量是基于所述已处理相邻图像块的控制点的运动矢量进行推导获得时，所述调整后的控制点的运动矢量通过如下公式获得：
    vx0＝K1>＝0？(K1+offset)>>mvShift:–((–K1+offset)>>mvShift)，
    vy0＝K2>＝0？(K2+offset)>>mvShift:–((–K2+offset)>>mvShift)，
    vx1＝K3>＝0？(K3+offset)>>mvShift:–((–K3+offset)>>mvShift)，
    vy1＝K4>＝0？(K4+offset)>>mvShift:–((–K4+offset)>>mvShift)，
    vx2＝K5>＝0？(K5+offset)>>mvShift:–((–K5+offset)>>mvShift)，
    vy2＝K6>＝0？(K6+offset)>>mvShift:–((–K6+offset)>>mvShift)，
    其中，
    K1＝mvScaleHor+dHorX*(x0–x4–M/2)+dHorY*(y0–y4–N/2)，
    K2＝mvScaleVer+dVerX*(x0–x4–M/2)+dVerY*(y0–y4–N/2)，
    K3＝mvScaleHor+dHorX*(x1–x4–M/2)+dHorY*(y1–y4–N/2)，
    K4＝mvScaleVer+dVerX*(x1–x4–M/2)+dVerY*(y1–y4–N/2)，
    K5＝mvScaleHor+dHorX*(x2–x4–M/2)+dHorY*(y2–y4–N/2)，
    K6＝mvScaleVer+dVerX*(x2–x4–M/2)+dVerY*(y2–y4–N/2)，
    offset＝1<<(mvShift–1)，
    mvScaleHor＝vx4<<7，
    mvScaleVer＝vy4<<7，
    dHorX＝(vx5–vx4)<<(7–log2(P))，
    dVerX＝(vy5–vy4)<<(7–log2(Q))，
    当所述已处理相邻图像块的所述仿射运动模型为6参数模型时，dHorY＝(vx6–vx4)<<(7–log2(P))，dVerY＝(vy6–vy4)<<(7–log2(Q))，
    当所述已处理相邻图像块的所述仿射运动模型为4参数模型时，dHorY＝–dVerX，dVerY＝dHorX，
    Log2()表示取2的对数的函数，<<表示左移位，>>表示右移位，P为所述已处理相邻图像块的宽度、Q为所述已处理相邻图像块的高度，
    (vx0,vy0)、(vx1,vy1)和(vx2,vy2)分别表示所述待处理图像块的三个控制点的运动矢量的水平分量和竖直分量，
    (vx4,vy4)、(vx5,vy5)和(vx6,vy6)分别表示所述已处理相邻图像块的三个控制点的运动矢量的水平分量和竖直分量，
    mvShift基于所述已处理相邻图像块的控制点的运动矢量精度确定。
  18. 根据权利要求15或17所述的方法，其特征在于，还包括：
    当所述调整后的控制点的运动矢量的比特深度大于所述第一运动矢量比特深度时，对所述调整后的控制点的运动矢量进行钳位以使所述调整后的控制点的运动矢量的比特深度等于所述第一运动矢量比特深度。
  19. 根据权利要求15或17所述的方法，其特征在于，还包括：
    对所述调整后的控制点的运动矢量进行钳位以使所述调整后的控制点的运动矢量的比特深度等于所述第一运动矢量比特深度。
  20. 根据权利要求13-19中任一项所述的方法，其特征在于，所述方法还包括：
    处理所述运动补偿单元的运动矢量精度以满足预设的第二运动矢量精度，和/或，处理所述运动补偿单元的运动矢量比特深度以满足预设的第二运动矢量精度比特深度；
    存储所述处理后的运动补偿单元的运动矢量。
  21. 根据权利要求20所述的方法，其特征在于，所述处理后的运动补偿单元的运动矢量通过如下公式获得：
    MCUMV’＝(MCUMV>>mvrShift2)，
    其中，MCUMV’表示所述处理后的运动补偿单元的运动矢量，MCUMV表示所述处理前的运动补偿单元的运动矢量，mvrShift2表示第二偏移值。
  22. 根据权利要求21所述的方法，其特征在于，还包括：
    将所述处理后的运动补偿单元的运动矢量的比特深度进行钳位以使所述处理后的运动补偿单元的运动矢量的比特深度等于所述第二运动矢量比特深度。
  23. 根据权利要求21所述的方法，其特征在于，还包括：
    当所述处理后的运动补偿单元的运动矢量的比特深度大于所述第二运动矢量比特深度时，对所述处理后的运动补偿单元的运动矢量进行钳位以使所述处理后的运动补 偿单元的运动矢量的比特深度等于所述第二运动矢量比特深度。
  24. 根据权利要求21-23任一项所述的方法，其特征在于，包括：
    当所述第二运动矢量精度为1/4像素精度且所述MCUMV的精度为1/16像素精度时，所述第二偏移值等于2；
    当所述第二运动矢量精度为1/4像素精度且所述MCUMV的精度为1/4像素精度时，所述第二偏移值等于0；
    当所述第二运动矢量精度为1/4像素精度且所述MCUMV的精度为1/32像素精度时，所述第二偏移值等于3。
  25. 根据权利要求13-24中任一项所述的方法，其特征在于，所述基于所述每个运动补偿单元的运动矢量，获取所述待处理图像块的重建块，包括：
    基于所述每个运动补偿单元的运动矢量，分别进行运动补偿，以获得所述待处理图像块的预测块；
    基于所述预测块和每个所述运动补偿单元的运动矢量，获得所述待处理图像块的重建块。
  26. 一种帧间预测的装置，其特征在于，包括：
    确定模块，用于确定待处理图像块的预测模式为基于仿射运动模型的先进运动矢量预测AMVP模式；
    获取模块，用于获得所述待处理图像块的控制点的运动矢量，所述控制点的运动矢量满足预设的第一运动矢量精度和/或第一运动矢量比特深度；
    计算模块，用于根据所述控制点的运动矢量，推导所述待处理图像块中每个运动补偿单元的运动矢量；
    重建模块，用于基于所述每个运动补偿单元的运动矢量，获取所述待处理图像块的重建块。
  27. 根据权利要求26所述的装置，其特征在于，所述获取模块具体用于：
    获取所述控制点的运动矢量差值CPMVD和所述控制点的运动矢量的预测值
    CPMVP；
    当所述CPMVD的精度不等于所述第一运动矢量精度时，根据所述CPMVD和第一偏移值，获得所述待处理图像块的控制点的运动矢量；或者，
    当所述CPMVP的精度不等于所述第一运动矢量精度时，根据所述CPMVP和第二偏移值，获得所述待处理图像块的控制点的运动矢量。
  28. 根据权利要求27所述的装置，其特征在于，所述待处理图像块的控制点的运动矢量通过如下公式获得：
    CPMV＝CPMVD’+CPMVP’，
    其中，
    当所述CPMVD的精度不等于所述第一运动矢量精度时，CPMVD’＝CPMVD<<mvrShift1；
    当所述CPMVD的精度等于所述第一运动矢量精度时，CPMVD’＝CPMVD；
    当所述CPMVP的精度不等于所述第一运动矢量精度时，CPMVP’＝CPMVP<<mvrShift2；
    当所述CPMVP的精度等于所述第一运动矢量精度时，CPMVP’＝CPMVP；
    CPMV表示所述控制点的运动矢量，mvrShift1表示所述第一偏移值，mvrShift2表示所述第二偏移值。
  29. 根据权利要求28所述的装置，其特征在于，所述获取模块还用于：
    当所述控制点的运动矢量的比特深度大于所述第一运动矢量比特深度时，对所述控制点的运动矢量进行钳位以使所述控制点的运动矢量的比特深度等于所述第一运动矢量比特深度。
  30. 根据权利要求28所述的装置，其特征在于，所述获取模块还用于：
    对所述控制点的运动矢量进行钳位以使所述控制点的运动矢量的比特深度等于所述第一运动矢量比特深度。
  31. 根据权利要求27-30中任一项所述的装置，其特征在于，包括：
    当所述第一运动矢量精度为1/16像素精度且所述CPMVD的精度为1/16像素精度时，所述第一偏移值等于0；
    当所述第一运动矢量精度为1/16像素精度且所述CPMVD的精度为1/4像素精度时，所述第一偏移值等于2；
    当所述第一运动矢量精度为1/16像素精度且所述CPMVD的精度为整像素精度时，所述第一偏移值等于4；
    当所述第一运动矢量精度为1/16像素精度且所述CPMVP的精度为1/16像素精度时，所述第二偏移值等于0；
    当所述第一运动矢量精度为1/16像素精度且所述CPMVP的精度为1/4像素精度时，所述第二偏移值等于2；
    当所述第一运动矢量精度为1/16像素精度且所述CPMVP的精度为整像素精度时，所述第二偏移值等于4。
  32. 根据权利要求26-31中任一项所述的装置，其特征在于，所述获取模块还用于：
    处理所述运动补偿单元的运动矢量精度以满足预设的第二运动矢量精度，和/或，处理所述运动补偿单元的运动矢量比特深度以满足预设的第二运动矢量精度比特深度；
    所述装置还包括存储模块：
    所述存储模块，用于存储所述处理后的运动补偿单元的运动矢量。
  33. 根据权利要求32所述的装置，其特征在于，所述处理后的运动补偿单元的运动矢量通过如下公式获得：
    MCUMV’＝(MCUMV>>mvrShift3)，
    其中，MCUMV’表示所述处理后的运动补偿单元的运动矢量，MCUMV表示所述处理前的运动补偿单元的运动矢量，mvrShift3表示第三偏移值。
  34. 根据权利要求33所述的装置，其特征在于，所述获取模块还用于：
    将所述处理后的运动补偿单元的运动矢量的比特深度进行钳位以使所述处理后的运动补偿单元的运动矢量的比特深度等于所述第二运动矢量比特深度。
  35. 根据权利要求33所述的装置，其特征在于，所述获取模块还用于：
    当所述处理后的运动补偿单元的运动矢量的比特深度大于所述第二运动矢量比特 深度时，对所述处理后的运动补偿单元的运动矢量进行钳位以使所述处理后的运动补偿单元的运动矢量的比特深度等于所述第二运动矢量比特深度。
  36. 根据权利要求33-35任一项所述的装置，其特征在于，包括：
    当所述第二运动矢量精度为1/4像素精度且所述MCUMV的精度为1/16像素精度时，所述第三偏移值等于2；
    当所述第二运动矢量精度为1/4像素精度且所述MCUMV的精度为1/4像素精度时，所述第三偏移值等于0；
    当所述第二运动矢量精度为1/4像素精度且所述MCUMV的精度为1/32像素精度时，所述第三偏移值等于3。
  37. 根据权利要求26-36中任一项所述的装置，其特征在于，所述重建模块具体用于：
    基于所述每个运动补偿单元的运动矢量，分别进行运动补偿，以获得所述待处理图像块的预测块；
    基于所述预测块和每个所述运动补偿单元的运动矢量，获得所述待处理图像块的重建块。
  38. 一种帧间预测的装置，其特征在于，包括：
    确定模块，用于确定待处理图像块的预测模式为基于仿射运动模型的融合Merge预测模式；
    获取模块，用于获得所述待处理图像块的控制点的运动矢量；
    调整模块，用于调整所述控制点的运动矢量以满足预设的第一运动矢量精度和/或第一运动矢量比特深度；
    计算模块，用于根据调整后的控制点的运动矢量，推导所述待处理图像块中每个运动补偿单元的运动矢量；
    重建模块，用于基于所述每个运动补偿单元的运动矢量，获取所述待处理图像块的重建块。
  39. 根据权利要求38所述的装置，其特征在于，所述调整模块具体用于：
    当所述控制点的运动矢量的精度不等于所述第一运动矢量精度时，根据所述控制点的运动矢量和第一偏移值，获得所述调整后的控制点的运动矢量。
  40. 根据权利要求39所述的装置，其特征在于，所述调整后的控制点的运动矢量通过如下公式获得：
    CPMV’＝CPMV<<mvrShift1，其中，CPMV表示所述控制点的运动矢量，CPMV’表示所述调整后的控制点的运动矢量，mvrShift1表示所述第一偏移值。
  41. 根据权利要求39或40所述的装置，其特征在于，包括：
    当所述第一运动矢量精度为1/16像素精度且所述控制点的运动矢量的精度为1/16像素精度时，所述第一偏移值等于0；
    当所述第一运动矢量精度为1/16像素精度且所述控制点的运动矢量的精度为1/4像素精度时，所述第一偏移值等于2；
    当所述第一运动矢量精度为1/16像素精度且所述控制点的运动矢量的精度为整像素精度时，所述第一偏移值等于4。
  42. 根据权利要求38所述的装置，其特征在于，所述待处理图像块的已处理相邻图像块的预测模式为基于仿射运动模型的预测模式，当所述待处理图像块的控制点的运动矢量是基于所述已处理相邻图像块的控制点的运动矢量进行推导获得时，所述调整后的控制点的运动矢量通过如下公式获得：
    vx0＝K1>＝0？(K1+offset)>>mvShift:–((–K1+offset)>>mvShift)，
    vy0＝K2>＝0？(K2+offset)>>mvShift:–((–K2+offset)>>mvShift)，
    vx1＝K3>＝0？(K3+offset)>>mvShift:–((–K3+offset)>>mvShift)，
    vy1＝K4>＝0？(K4+offset)>>mvShift:–((–K4+offset)>>mvShift)，
    vx2＝K5>＝0？(K5+offset)>>mvShift:–((–K5+offset)>>mvShift)，
    vy2＝K6>＝0？(K6+offset)>>mvShift:–((–K6+offset)>>mvShift)，
    其中，
    K1＝mvScaleHor+dHorX*(x0–x4–M/2)+dHorY*(y0–y4–N/2)，
    K2＝mvScaleVer+dVerX*(x0–x4–M/2)+dVerY*(y0–y4–N/2)，
    K3＝mvScaleHor+dHorX*(x1–x4–M/2)+dHorY*(y1–y4–N/2)，
    K4＝mvScaleVer+dVerX*(x1–x4–M/2)+dVerY*(y1–y4–N/2)，
    K5＝mvScaleHor+dHorX*(x2–x4–M/2)+dHorY*(y2–y4–N/2)，
    K6＝mvScaleVer+dVerX*(x2–x4–M/2)+dVerY*(y2–y4–N/2)，
    offset＝1<<(mvShift–1)，
    mvScaleHor＝vx4<<7，
    mvScaleVer＝vy4<<7，
    dHorX＝(vx5–vx4)<<(7–log2(P))，
    dVerX＝(vy5–vy4)<<(7–log2(Q))，
    当所述已处理相邻图像块的所述仿射运动模型为6参数模型时，dHorY＝(vx6–vx4)<<(7–log2(P))，dVerY＝(vy6–vy4)<<(7–log2(Q))，
    当所述已处理相邻图像块的所述仿射运动模型为4参数模型时，dHorY＝–dVerX，dVerY＝dHorX，
    Log2()表示取2的对数的函数，<<表示左移位，>>表示右移位，P为所述已处理相邻图像块的宽度、Q为所述已处理相邻图像块的高度，
    (vx0,vy0)、(vx1,vy1)和(vx2,vy2)分别表示所述待处理图像块的三个控制点的运动矢量的水平分量和竖直分量，
    (vx4,vy4)、(vx5,vy5)和(vx6,vy6)分别表示所述已处理相邻图像块的三个控制点的运动矢量的水平分量和竖直分量，
    mvShift基于所述已处理相邻图像块的控制点的运动矢量精度确定。
  43. 根据权利要求40或42所述的装置，其特征在于，所述调整模块还用于：
    当所述调整后的控制点的运动矢量的比特深度大于所述第一运动矢量比特深度时，对所述调整后的控制点的运动矢量进行钳位以使所述调整后的控制点的运动矢量的比特深度等于所述第一运动矢量比特深度。
  44. 根据权利要求40或42所述的装置，其特征在于，所述调整模块还用于：
    对所述调整后的控制点的运动矢量进行钳位以使所述调整后的控制点的运动矢量 的比特深度等于所述第一运动矢量比特深度。
  45. 根据权利要求38-44中任一项所述的装置，其特征在于，所述调整模块还用于：
    处理所述运动补偿单元的运动矢量精度以满足预设的第二运动矢量精度，和/或，处理所述运动补偿单元的运动矢量比特深度以满足预设的第二运动矢量精度比特深度；
    所述装置还包括存储模块：
    所述存储模块，用于存储所述处理后的运动补偿单元的运动矢量。
  46. 根据权利要求45所述的装置，其特征在于，所述处理后的运动补偿单元的运动矢量通过如下公式获得：
    MCUMV’＝(MCUMV>>mvrShift2)，
    其中，MCUMV’表示所述处理后的运动补偿单元的运动矢量，MCUMV表示所述处理前的运动补偿单元的运动矢量，mvrShift2表示第二偏移值。
  47. 根据权利要求46所述的装置，其特征在于，所述调整模块还用于：
    将所述处理后的运动补偿单元的运动矢量的比特深度进行钳位以使所述处理后的运动补偿单元的运动矢量的比特深度等于所述第二运动矢量比特深度。
  48. 根据权利要求46所述的装置，其特征在于，所述调整模块还用于：
    当所述处理后的运动补偿单元的运动矢量的比特深度大于所述第二运动矢量比特深度时，对所述处理后的运动补偿单元的运动矢量进行钳位以使所述处理后的运动补偿单元的运动矢量的比特深度等于所述第二运动矢量比特深度。
  49. 根据权利要求46-48任一项所述的装置，其特征在于，包括：
    当所述第二运动矢量精度为1/4像素精度且所述MCUMV的精度为1/16像素精度时，所述第二偏移值等于2；
    当所述第二运动矢量精度为1/4像素精度且所述MCUMV的精度为1/4像素精度时，所述第二偏移值等于0；
    当所述第二运动矢量精度为1/4像素精度且所述MCUMV的精度为1/32像素精度时，所述第二偏移值等于3。
  50. 根据权利要求38-49中任一项所述的装置，其特征在于，所述重建模块具体用于：
    基于所述每个运动补偿单元的运动矢量，分别进行运动补偿，以获得所述待处理图像块的预测块；
    基于所述预测块和每个所述运动补偿单元的运动矢量，获得所述待处理图像块的重建块。
  51. 一种视频编解码设备，其特征在于，包括：相互耦合的非易失性存储器和处理器，所述处理器调用存储在所述存储器中的程序代码以执行如权利要求1-12或权利要求13-25中任一项所述的方法。
  52. 一种帧间预测的方法，其特征在于，包括：
    获取待处理图像块的控制点的运动矢量差值CPMVD和所述控制点的运动矢量的预测值CPMVP；
    对所述CPMVD左移第一偏移值，其中，当所述CPMVD的精度等于第一运动矢 量精度时，所述第一偏移值为0；
    对所述CPMVP左移第二偏移值，其中，当所述CPMVP的精度等于所述第一运动矢量精度时，所述第二偏移值为0；
    将所述左移后的CPMVD和所述左移后的CPMVP相加，以获得所述控制点的运动矢量；
    根据所述控制点的运动矢量，推导所述待处理图像块中每个运动补偿单元的运动矢量；
    基于所述每个运动补偿单元的运动矢量，获取所述待处理图像块的重建块。
  53. 根据权利要求52所述的方法，其特征在于，还包括：
    当所述控制点的运动矢量的比特深度大于第一运动矢量比特深度时，对所述控制点的运动矢量进行钳位以使所述控制点的运动矢量的比特深度等于所述第一运动矢量比特深度。
  54. 根据权利要求52所述的方法，其特征在于，还包括：
    对所述控制点的运动矢量进行钳位以使所述控制点的运动矢量的比特深度等于所述第一运动矢量比特深度。
  55. 根据权利要求52-54中任一项所述的方法，其特征在于，所述第一运动矢量精度为1/16像素精度。
  56. 根据权利要求55所述的方法，其特征在于，
    当所述CPMVD的精度为1/16像素精度时，所述第一偏移值等于0；
    当所述CPMVD的精度为1/4像素精度时，所述第一偏移值等于2；
    当所述CPMVD的精度为整像素精度时，所述第一偏移值等于4；
    当所述CPMVP的精度为1/16像素精度时，所述第二偏移值等于0；
    当所述CPMVP的精度为1/4像素精度时，所述第二偏移值等于2；
    当所述CPMVP的精度为整像素精度时，所述第二偏移值等于4。
  57. 根据权利要求52-56中任一项所述的方法，其特征在于，所述方法还包括：
    处理所述运动补偿单元的运动矢量以满足预设的第二运动矢量精度；
    存储所述处理后的运动补偿单元的运动矢量。
  58. 根据权利要求57所述的方法，其特征在于，所述处理所述运动补偿单元的运动矢量包括：
    对所述运动补偿单元的运动矢量左移第三偏移值。
  59. 根据权利要求58所述的方法，其特征在于，还包括：
    将所述处理后的运动补偿单元的运动矢量的比特深度进行钳位以使所述处理后的运动补偿单元的运动矢量的比特深度等于所述第二运动矢量比特深度。
  60. 根据权利要求58所述的方法，其特征在于，还包括：
    当所述处理后的运动补偿单元的运动矢量的比特深度大于所述第二运动矢量比特深度时，对所述处理后的运动补偿单元的运动矢量进行钳位以使所述处理后的运动补偿单元的运动矢量的比特深度等于所述第二运动矢量比特深度。
  61. 根据权利要求57-60中任一项所述的方法，其特征在于，所述第二运动矢量精度为1/4像素精度。
  62. 根据权利要求61所述的方法，其特征在于，
    当所述运动补偿单元的运动矢量的精度为1/16像素精度时，所述第三偏移值等于2；
    当所述运动补偿单元的运动矢量的精度为1/4像素精度时，所述第三偏移值等于0；
    当所述运动补偿单元的运动矢量的精度为1/32像素精度时，所述第三偏移值等于3。
  63. 根据权利要求52-62中任一项所述的方法，其特征在于，所述基于所述每个运动补偿单元的运动矢量，获取所述待处理图像块的重建块，包括：
    基于所述每个运动补偿单元的运动矢量，分别进行运动补偿，以获得所述待处理图像块的预测块；
    基于所述预测块和每个所述运动补偿单元的运动矢量，获得所述待处理图像块的重建块。
  64. 一种帧间预测的装置，其特征在于，包括：
    获取模块，用于获取待处理图像块的控制点的运动矢量差值CPMVD和所述控制点的运动矢量的预测值CPMVP；
    所述获取模块，还用于对所述CPMVD左移第一偏移值，其中，当所述CPMVD的精度等于第一运动矢量精度时，所述第一偏移值为0；
    所述获取模块，还用于对所述CPMVP左移第二偏移值，其中，当所述CPMVP的精度等于所述第一运动矢量精度时，所述第二偏移值为0；
    所述获取模块，还用于将所述左移后的CPMVD和所述左移后的CPMVP相加，以获得所述控制点的运动矢量；
    计算模块，用于根据所述控制点的运动矢量，推导所述待处理图像块中每个运动补偿单元的运动矢量；
    重建模块，用于基于所述每个运动补偿单元的运动矢量，获取所述待处理图像块的重建块。
  65. 根据权利要求64所述的装置，其特征在于，所述获取模块还用于：
    当所述控制点的运动矢量的比特深度大于第一运动矢量比特深度时，对所述控制点的运动矢量进行钳位以使所述控制点的运动矢量的比特深度等于所述第一运动矢量比特深度。
  66. 根据权利要求64所述的装置，其特征在于，所述获取模块还用于：
    对所述控制点的运动矢量进行钳位以使所述控制点的运动矢量的比特深度等于所述第一运动矢量比特深度。
  67. 根据权利要求64-66中任一项所述的装置，其特征在于，所述第一运动矢量精度为1/16像素精度。
  68. 根据权利要求67所述的装置，其特征在于，
    当所述CPMVD的精度为1/16像素精度时，所述第一偏移值等于0；
    当所述CPMVD的精度为1/4像素精度时，所述第一偏移值等于2；
    当所述CPMVD的精度为整像素精度时，所述第一偏移值等于4；
    当所述CPMVP的精度为1/16像素精度时，所述第二偏移值等于0；
    当所述CPMVP的精度为1/4像素精度时，所述第二偏移值等于2；
    当所述CPMVP的精度为整像素精度时，所述第二偏移值等于4。
  69. 根据权利要求64-68中任一项所述的装置，其特征在于，所述获取模块还用于：
    处理所述运动补偿单元的运动矢量以满足预设的第二运动矢量精度；
    所述装置还包括存储模块：
    所述存储模块，用于存储所述处理后的运动补偿单元的运动矢量。
  70. 根据权利要求69所述的装置，其特征在于，
    所述获取模块用于对所述运动补偿单元的运动矢量左移第三偏移值。
  71. 根据权利要求70所述的装置，其特征在于，所述获取模块还用于：
    将所述处理后的运动补偿单元的运动矢量的比特深度进行钳位以使所述处理后的运动补偿单元的运动矢量的比特深度等于所述第二运动矢量比特深度。
  72. 根据权利要求70所述的装置，其特征在于，所述获取模块还用于：
    当所述处理后的运动补偿单元的运动矢量的比特深度大于所述第二运动矢量比特深度时，对所述处理后的运动补偿单元的运动矢量进行钳位以使所述处理后的运动补偿单元的运动矢量的比特深度等于所述第二运动矢量比特深度。
  73. 根据权利要求69-72中任一项所述的装置，其特征在于，所述第二运动矢量精度为1/4像素精度。
  74. 根据权利要求73所述的装置，其特征在于，
    当所述运动补偿单元的运动矢量的精度为1/16像素精度时，所述第三偏移值等于2；
    当所述运动补偿单元的运动矢量的精度为1/4像素精度时，所述第三偏移值等于0；
    当所述运动补偿单元的运动矢量的精度为1/32像素精度时，所述第三偏移值等于3。
  75. 根据权利要求64-74中任一项所述的装置，其特征在于，所述重建模块具体用于：
    基于所述每个运动补偿单元的运动矢量，分别进行运动补偿，以获得所述待处理图像块的预测块；
    基于所述预测块和每个所述运动补偿单元的运动矢量，获得所述待处理图像块的重建块。
  76. 一种视频编解码设备，其特征在于，包括：相互耦合的非易失性存储器和处理器，所述处理器调用存储在所述存储器中的程序代码以执行如权利要求52-63中任一项所述的方法。
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