Error surface based sub-pixel accurate refinement method for decoder side motion vector refinement

    公开(公告)号:US12003754B2

    公开(公告)日:2024-06-04

    申请号:US17573331

    申请日:2022-01-11

    CPC classification number: H04N19/513 H04N19/523

    Abstract: Given that decoder side motion vector refinement/derivation is a normative aspect of a coding system, the encoder will also have to perform the same error surface technique in order to not have any drift between the encoder's reconstruction and the decoder's reconstruction. Hence, all aspects of all embodiments are applicable to both encoding and decoding systems. In template matching, the refinement movement occurs only in the reference starting from the sub-pixel accurate center that is derived based on the explicitly signaled merge index or implicitly through cost evaluations. In bilateral matching (with or without averaged template), the refinements start in the reference lists L0 and L1 starting from the respective sub-pixel accurate centers that are derived based on the explicitly signaled merge index or implicitly through cost evaluations.

    Error surface based sub-pixel accurate refinement method for decoder side motion vector refinement

    公开(公告)号:US11310521B2

    公开(公告)日:2022-04-19

    申请号:US17100924

    申请日:2020-11-22

    Abstract: Given that decoder side motion vector refinement/derivation is a normative aspect of a coding system, the encoder will also have to perform the same error surface technique in order to not have any drift between the encoder's reconstruction and the decoder's reconstruction. Hence, all aspects of all embodiments are applicable to both encoding and decoding systems. In template matching, the refinement movement occurs only in the reference starting from the sub-pixel accurate center that is derived based on the explicitly signaled merge index or implicitly through cost evaluations. In bilateral matching (with or without averaged template), the refinements start in the reference lists L0 and L1 starting from the respective sub-pixel accurate centers that are derived based on the explicitly signaled merge index or implicitly through cost evaluations.

    ENCODER, A DECODER AND CORRESPONDING METHODS FOR INTER PREDICTION

    公开(公告)号:US20220014776A1

    公开(公告)日:2022-01-13

    申请号:US17467785

    申请日:2021-09-07

    Abstract: A bidirectional optical flowing prediction method includes obtaining an initial motion vector pair for a current block, obtaining a forward and a backward prediction block according to the forward motion vector and a backward prediction block according to the initial motion vector pair, and calculating gradient parameters for a current sample in the current block. The method further includes obtaining at least two sample optical flow parameters, including a first parameter and a second parameter, for the current sample based on the gradient parameters, obtaining block optical flow parameters based on sample optical flow parameters of samples in the current block, and obtaining a prediction value of the current block. One of the block optical flow parameters is obtained by multiplying the first parameter and a sign function of the second parameter, and the sign function is a piecewise function with at least three subintervals.

    DECODER-SIDE MOTION VECTOR REFINEMENT (DMVR) PROCESS METHOD AND APPARATUS

    公开(公告)号:US20210368202A1

    公开(公告)日:2021-11-25

    申请号:US17394598

    申请日:2021-08-05

    Abstract: Methods and apparatuses of determining an alignment level between motion compensated reference patches for reducing motion vector refinement steps are provided. According to one method, obtaining, by a decoder, motion compensated interpolated samples based on sub-pixel accurate merge motion vectors from a bilinear motion compensated interpolation; computing, by the decoder, a sum of absolute differences (SAD) between two motion compensated reference patches using a subset of the motion compensated interpolated samples; determining, by the decoder, whether the SAD is less than a coding unit (CU) size-dependent threshold value; when the SAD is less than the CU size-dependent threshold value: skipping remaining decoder-side motion vector refinement (DMVR) process steps; and performing final motion compensation; and when the SAD is not less than the CU size-dependent threshold value: performing the remaining DMVR process steps; and performing the final motion compensation.

    Early termination for optical flow refinement

    公开(公告)号:US11985320B2

    公开(公告)日:2024-05-14

    申请号:US17407617

    申请日:2021-08-20

    Abstract: It is provided a method of video coding implemented in a decoding device or an encoding device, the method comprising: obtaining initial motion vectors for a current block; obtaining first predictions for a sample value in the current block based on the initial motion vectors; calculating a first matching cost according to the first predictions; determining whether an optical flow refinement process should be performed or not, according to at least one preset condition, the at least one preset condition comprising a condition of whether the calculated first matching cost is equal to or larger than a threshold value; and performing an optical flow refinement process for obtaining a final inter prediction for the sample value in the current block, when it is determined that the optical flow refinement process should be performed.

    Skipping refinement based on patch similarity in bilinear interpolation based decoder-side motion vector refinement

    公开(公告)号:US11178426B2

    公开(公告)日:2021-11-16

    申请号:US17103822

    申请日:2020-11-24

    Abstract: Methods and apparatuses of determining an alignment level between motion compensated reference patches for reducing motion vector refinement steps are provided. According to one method, obtaining, by a decoder, motion compensated interpolated samples based on sub-pixel accurate merge motion vectors from a bilinear motion compensated interpolation; computing, by the decoder, a sum of absolute differences (SAD) between two motion compensated reference patches using a subset of the motion compensated interpolated samples; determining, by the decoder, whether the SAD is less than a coding unit (CU) size-dependent threshold value; when the SAD is less than the CU size-dependent threshold value: skipping remaining decoder-side motion vector refinement (DMVR) process steps; and performing final motion compensation; and when the SAD is not less than the CU size-dependent threshold value: performing the remaining DMVR process steps; and performing the final motion compensation.

    Skipping refinement based on patch similarity in bilinear interpolation based decoder-side motion vector refinement

    公开(公告)号:US11146814B2

    公开(公告)日:2021-10-12

    申请号:US17103822

    申请日:2020-11-24

    Abstract: Methods and apparatuses of determining an alignment level between motion compensated reference patches for reducing motion vector refinement steps are provided. According to one method, obtaining, by a decoder, motion compensated interpolated samples based on sub-pixel accurate merge motion vectors from a bilinear motion compensated interpolation; computing, by the decoder, a sum of absolute differences (SAD) between two motion compensated reference patches using a subset of the motion compensated interpolated samples; determining, by the decoder, whether the SAD is less than a coding unit (CU) size-dependent threshold value; when the SAD is less than the CU size-dependent threshold value: skipping remaining decoder-side motion vector refinement (DMVR) process steps; and performing final motion compensation; and when the SAD is not less than the CU size-dependent threshold value: performing the remaining DMVR process steps; and performing the final motion compensation.

    Image Prediction Method and Apparatus
    10.
    发明申请

    公开(公告)号:US20200213616A1

    公开(公告)日:2020-07-02

    申请号:US16815914

    申请日:2020-03-11

    Abstract: An image prediction method and apparatus includes obtaining predicted motion information of an image block; determining an initial predicted block of the image block according to the predicted motion information and a reference image of the image block; performing, according to the predicted motion information, L iterative searches in the reference image using an integer pixel step size to obtain an intermediate predicted block of the image block; performing a single search in the reference image using a fractional pixel step size to obtain M predicted blocks of the image block; determining a target predicted block of the image block according to the M predicted blocks and the intermediate predicted block; and obtaining a predicted value of a pixel value of the image block according to a pixel value of the target predicted block.

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