US 12,069,297 B2
Methods and apparatuses for prediction refinement with optical flow, bi-directional optical flow, and decoder-side motion vector refinement
Xiaoyu Xiu, San Diego, CA (US); Yi-Wen Chen, San Diego, CA (US); Xianglin Wang, San Diego, CA (US); and Bing Yu, 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 Apr. 6, 2022, as Appl. No. 17/714,916.
Application 17/714,916 is a continuation of application No. PCT/US2020/055153, filed on Oct. 9, 2020.
Claims priority of provisional application 62/913,141, filed on Oct. 9, 2019.
Prior Publication US 2022/0239943 A1, Jul. 28, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 19/00 (2014.01); H04N 19/105 (2014.01); H04N 19/132 (2014.01); H04N 19/139 (2014.01); H04N 19/176 (2014.01); H04N 19/513 (2014.01); H04N 19/577 (2014.01); H04N 19/70 (2014.01)
CPC H04N 19/577 (2014.11) [H04N 19/105 (2014.11); H04N 19/132 (2014.11); H04N 19/139 (2014.11); H04N 19/176 (2014.11); H04N 19/513 (2014.11); H04N 19/70 (2014.11)] 12 Claims
OG exemplary drawing
 
1. A method of prediction refinement with optical flow (PROF) for decoding a video signal, comprising:
obtaining, at a decoder, a reference picture I associated with a video block;
obtaining, at the decoder, initial prediction samples of the video block from a reference block in the reference picture I;
deriving, at the decoder, internal PROF parameters of a PROF derivation process by applying right-shifting operations, wherein the internal PROF parameters comprise horizontal gradient values, vertical gradient values, horizontal motion difference values, and vertical motion difference values derived for samples in the video block;
obtaining, at the decoder, prediction refinement values for the samples in the video block based on the internal PROF parameters; and
obtaining, at the decoder, refined prediction samples of the video block based on the initial prediction samples and the prediction refinement values.