US 11,949,857 B2
Method, apparatus and system for encoding and decoding a tree of blocks of video samples
Christopher James Rosewarne, Concord West (AU)
Assigned to Canon Kabushiki Kaisha, Tokyo (JP)
Appl. No. 17/435,997
Filed by Canon Kabushiki Kaisha, Tokyo (JP)
PCT Filed Jan. 20, 2020, PCT No. PCT/AU2020/050027
§ 371(c)(1), (2) Date Sep. 2, 2021,
PCT Pub. No. WO2020/181316, PCT Pub. Date Sep. 17, 2020.
Claims priority of application No. 2019201649 (AU), filed on Mar. 11, 2019.
Prior Publication US 2022/0150479 A1, May 12, 2022
Int. Cl. H04N 19/11 (2014.01); H04N 19/119 (2014.01); H04N 19/159 (2014.01); H04N 19/176 (2014.01); H04N 19/186 (2014.01); H04N 19/593 (2014.01); H04N 19/96 (2014.01)
CPC H04N 19/11 (2014.11) [H04N 19/119 (2014.11); H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/186 (2014.11); H04N 19/593 (2014.11); H04N 19/96 (2014.11)] 12 Claims
OG exemplary drawing
 
1. A method of decoding coding blocks of a coding tree unit for an image frame, from a bitstream, the method comprising:
determining a chroma format of the image frame, the chroma format having chroma channels of the image frame being subsampled relative to a luma channel of the image frame, wherein the determined chroma format is 4:2:0;
recursively splitting the coding tree unit into one or more coding units each of which has a luma coding block and chroma coding blocks, using a single tree;
determining whether further split for a chroma coding block is allowed,
wherein, if a block size of a luma coding block of a current coding unit is 8×8 and a block size of chroma coding blocks of the current coding unit is 4×4, a quad split for the chroma coding blocks of the current coding unit is not allowed even if the luma coding block of the current coding unit is split by a quad split, and
the chroma coding blocks, having the block size of 4×4, of the current coding unit are collocated with four luma coding blocks resulted from a quad split for the luma coding block, having the block size of 8×8, of the current coding unit if the luma coding block of the current coding unit is split by a quad split;
determining that the chroma coding blocks of the current coding unit are to be decoded using intra prediction if the block size of the luma coding block of the current coding unit is 8×8, the block size of the chroma coding blocks of the current coding unit is 4×4, and a current split mode for the current coding unit is a quad split; and
decoding the chroma coding blocks of the current coding unit using intra prediction if it is determined that the chroma coding blocks of the current coding unit are to be decoded using intra prediction.