US 11,889,110 B2
Methods and apparatus for prediction refinement with optical flow
Xiaoyu Xiu, San Diego, CA (US); Yi-Wen Chen, San Diego, CA (US); Xianglin Wang, San Diego, CA (US); Shuiming Ye, San Diego, CA (US); Tsung-Chuan Ma, San Diego, CA (US); and Hong-Jheng Jhu, Beijing (CN)
Assigned to Beijing Dajia Internet Information Technology Co., Ltd., Beijing (CN)
Filed by BEIJING DAJIA INTERNET INFORMATION TECHNOLOGY CO., LTD., Beijing (CN)
Filed on Dec. 20, 2021, as Appl. No. 17/556,919.
Application 17/556,919 is a continuation of application No. PCT/US2020/038701, filed on Jun. 19, 2020.
Claims priority of provisional application 62/863,830, filed on Jun. 19, 2019.
Prior Publication US 2022/0116655 A1, Apr. 14, 2022
Int. Cl. H04N 19/577 (2014.01); H04N 19/105 (2014.01); H04N 19/132 (2014.01); H04N 19/139 (2014.01); H04N 19/149 (2014.01); H04N 19/159 (2014.01); H04N 19/176 (2014.01); H04N 19/184 (2014.01); H04N 19/196 (2014.01); H04N 19/44 (2014.01); H04N 19/513 (2014.01)
CPC H04N 19/577 (2014.11) [H04N 19/105 (2014.11); H04N 19/132 (2014.11); H04N 19/139 (2014.11); H04N 19/149 (2014.11); H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/184 (2014.11); H04N 19/196 (2014.11); H04N 19/44 (2014.11); H04N 19/513 (2014.11)] 20 Claims
OG exemplary drawing
 
1. A method of local illumination compensation (LIC) and prediction refinement with optical flow (PROF) for decoding a video signal, comprising:
obtaining, at a decoder, a first reference picture I associated with a video block that is coded by affine mode within the video signal;
obtaining, at the decoder, control point motion vectors (CPMVs) of an affine coding block based on the video block;
obtaining, at the decoder, prediction samples I(i, j) of the affine coding block from reference samples in the first reference picture I based on the CPMVs, wherein i and j represent a coordinate of one sample within the video block;
deriving, at the decoder, PROF prediction sample refinements of the affine coding block based on the PROF;
receiving, at the decoder, an LIC flag that indicates whether the LIC is applied to the affine coding block;
deriving, at the decoder and in response to determining that the LIC is applied, LIC weight and offset based on neighboring reconstructed samples of the affine coding block and their corresponding reference samples in the first reference picture; and
obtaining, at the decoder, final prediction samples of the affine coding block based on the PROF prediction sample refinements and the LIC weight and offset.