US 12,273,532 B2
Method and apparatus for prediction refinement with optical flow for an affine coded block
Huanbang Chen, Shenzhen (CN); Haitao Yang, Shenzhen (CN); and Jianle Chen, San Diego, CA (US)
Assigned to HUAWEI TECHNOLOGIES CO., LTD., Guangdong (CN)
Filed by HUAWEI TECHNOLOGIES CO., LTD., Guangdong (CN)
Filed on May 3, 2024, as Appl. No. 18/654,446.
Application 18/654,446 is a continuation of application No. 17/478,697, filed on Sep. 17, 2021, granted, now 12,003,733.
Application 17/478,697 is a continuation of application No. PCT/CN2020/080412, filed on Mar. 20, 2020.
Claims priority of provisional application 62/839,765, filed on Apr. 28, 2019.
Claims priority of provisional application 62/821,440, filed on Mar. 20, 2019.
Prior Publication US 2024/0364895 A1, Oct. 31, 2024
Int. Cl. H04N 19/139 (2014.01); H04N 19/119 (2014.01); H04N 19/172 (2014.01); H04N 19/174 (2014.01); H04N 19/176 (2014.01); H04N 19/52 (2014.01)
CPC H04N 19/139 (2014.11) [H04N 19/119 (2014.11); H04N 19/172 (2014.11); H04N 19/174 (2014.11); H04N 19/176 (2014.11); H04N 19/52 (2014.11)] 15 Claims
OG exemplary drawing
 
1. A method for prediction refinement with optical flow (PROF) for an affine coded block, comprising:
when a first indicator is set equal to true, performing a PROF process for a current sub-block of the affine coded block to obtain refined prediction sample values of the current sub-block of the affine coded block;
wherein when a plurality of constraint conditions for applying PROF are not fulfilled for the affine coded block, the first indicator is set equal to true; when one or more of the plurality of constraint conditions for applying PROF is fulfilled for the affine coded block, the first indicator is set equal to false;
wherein the plurality of constraint conditions for applying PROF comprises:
first indication information indicating that PROF is disabled for a picture containing the affine coded block; and
second indication information indicating no partition of the affine coded block;
wherein the performing the PROF process for the current sub-block of the affine coded block comprises:
obtaining a second prediction matrix, wherein the second prediction matrix is generated based on motion information of the current sub-block;
generating a horizontal prediction gradient matrix and a vertical prediction gradient matrix based on the second prediction matrix, wherein the horizontal prediction gradient matrix and the vertical prediction gradient matrix have a same size and a size of the second prediction matrix is greater than or equal to the size of the horizontal prediction gradient matrix and the vertical prediction gradient matrix;
calculating a delta prediction value of a current sample of the current sub-block based on a horizontal prediction gradient value of a current sample in the horizontal prediction gradient matrix, a vertical prediction gradient value of a current sample in the vertical prediction gradient matrix, and a difference between a motion vector of the current sample of the current sub-block and a motion vector of a center sample of the current sub-block; and
obtaining a refined prediction sample value of the current sample of the current sub-block based on the delta prediction value of the current sample and a prediction sample value of the current sample of the current sub-block.