US 11,930,177 B2
Primary transforms for cross-component level reconstruction
Madhu Peringassery Krishnan, Mountain View, CA (US); Xin Zhao, San Jose, CA (US); and Shan Liu, San Jose, CA (US)
Assigned to Tencent America LLC, Palo Alto, CA (US)
Filed by Tencent America LLC, Palo Alto, CA (US)
Filed on Oct. 14, 2022, as Appl. No. 17/966,390.
Claims priority of provisional application 63/289,133, filed on Dec. 13, 2021.
Claims priority of provisional application 63/273,789, filed on Oct. 29, 2021.
Prior Publication US 2023/0143151 A1, May 11, 2023
Int. Cl. H04N 19/12 (2014.01); H04N 19/176 (2014.01); H04N 19/18 (2014.01); H04N 19/186 (2014.01); H04N 19/46 (2014.01)
CPC H04N 19/12 (2014.11) [H04N 19/176 (2014.11); H04N 19/18 (2014.11); H04N 19/186 (2014.11); H04N 19/46 (2014.11)] 20 Claims
OG exemplary drawing
 
1. A method for video processing, the method comprising:
receiving a bitstream of a video block comprising a first transform block of a first color component and a second transform block of a second color component, wherein the first transform block and the second transform blocks are co-located blocks;
obtaining the first transform block of the first color component and the second transform block of the second color component from the bitstream of the video block;
determining a first flag indicating that all transform coefficients in the first transform block are zero;
determining a second flag indicating that a cross component level reconstruction (CCLR) is applied to the first transform block; and
in response to determining that CCLR is applied to the first transform block:
refining one or more of the transform coefficients in the first transform block by adding one or more offset values, to obtain a refined first transform block, the one or more offset values being derived based on transform coefficients that are in the second transform block and are co-located with the one or more of the transform coefficients in the first transform block;
determining a target transform kernel for the refined first transform block;
performing a reverse transform on the refined first transform block based on the target transform kernel to obtain a target block; and
reconstructing the first color component of the video block based on at least the target block.