US 12,238,279 B2
Bi-prediction refinement in affine with optical flow
Ya Chen, Cesson-Sevigne (FR); Franck Galpin, Cesson-Sevigne (FR); Fabrice Leleannec, Cesson-Sevigne (FR); and Antoine Robert, Cesson-Sevigne (FR)
Assigned to InterDigital CE Patent Holdings, SAS, Paris (FR)
Appl. No. 17/611,699
Filed by InterDigital CE Patent Holdings, SAS, Paris (FR)
PCT Filed Jun. 23, 2020, PCT No. PCT/EP2020/067545
§ 371(c)(1), (2) Date Nov. 16, 2021,
PCT Pub. No. WO2021/001220, PCT Pub. Date Jan. 7, 2021.
Claims priority of application No. 19305885 (EP), filed on Jul. 1, 2019.
Prior Publication US 2022/0264146 A1, Aug. 18, 2022
Int. Cl. H04N 19/107 (2014.01); H04N 19/105 (2014.01); H04N 19/176 (2014.01); H04N 19/513 (2014.01); H04N 19/577 (2014.01); H04N 19/523 (2014.01); H04N 19/563 (2014.01)
CPC H04N 19/107 (2014.11) [H04N 19/105 (2014.11); H04N 19/176 (2014.11); H04N 19/513 (2014.11); H04N 19/577 (2014.11); H04N 19/523 (2014.11); H04N 19/563 (2014.11)] 16 Claims
OG exemplary drawing
 
1. A method, comprising:
accessing a block to be decoded in affine mode, said block including a plurality of sub-blocks;
for one sub-block of said plurality of sub-blocks, obtaining a first and second prediction block, from a first and second reference picture, respectively, using sub-block based affine motion-compensated prediction, said one block in a bi-prediction mode;
obtaining motion refinement for said one sub-block, based on said first and second prediction blocks and spatial gradients in said first and second prediction blocks, according to a temporal optical flow model and a spatial optical flow model, wherein said motion refinement for said one sub-block is based on a linear combination of a motion difference according to said spatial optical flow model and an initial motion refinement for said one sub-block according to said temporal optical flow model;
obtaining a prediction adjustment for said one sub-block, based on said motion refinement and said spatial gradients; and
decoding said one sub-block based on said prediction adjustment, said first prediction block and said second prediction block.