US 12,244,812 B2
Transform-based image coding method and device therefor
Moonmo Koo, Seoul (KR); Hyeongmoon Jang, Seoul (KR); Jaehyun Lim, Seoul (KR); Seunghwan Kim, Seoul (KR); and Mehdi Salehifar, Seoul (KR)
Assigned to LG ELECTRONICS INC., Seoul (KR)
Appl. No. 17/910,493
Filed by LG ELECTRONICS INC., Seoul (KR)
PCT Filed Mar. 23, 2021, PCT No. PCT/KR2021/003540
§ 371(c)(1), (2) Date Sep. 9, 2022,
PCT Pub. No. WO2021/194199, PCT Pub. Date Sep. 30, 2021.
Claims priority of provisional application 63/007,348, filed on Apr. 8, 2020.
Claims priority of provisional application 63/005,227, filed on Apr. 4, 2020.
Claims priority of provisional application 63/004,459, filed on Apr. 2, 2020.
Claims priority of provisional application 62/994,270, filed on Mar. 24, 2020.
Prior Publication US 2023/0128355 A1, Apr. 27, 2023
Int. Cl. H04N 19/132 (2014.01); H04N 19/176 (2014.01); H04N 19/18 (2014.01); H04N 19/46 (2014.01); H04N 19/96 (2014.01)
CPC H04N 19/132 (2014.11) [H04N 19/176 (2014.11); H04N 19/18 (2014.11); H04N 19/46 (2014.11); H04N 19/96 (2014.11)] 5 Claims
OG exemplary drawing
 
1. A method of decoding an image performed by a decoding apparatus, the method comprising:
receiving residual information from a bitstream;
deriving a transform coefficient for a current block including a luma component and chroma components based on the residual information;
determining whether a tree type of the current block is a single tree;
obtaining, in response to the tree type of the current block being the single tree, a Low frequency non-separable transform (LFNST) index based on at least one of (i) that a non-zero transform coefficient for the luma component of the current block exists or (ii) that an Intra Sub-Partition (ISP) is applied to the luma component; and
deriving a modified transform coefficient by applying an LFNST kernel derived based on the LFNST index to the transform coefficient of the current block,
wherein, based on the tree type of the current block being the single tree, the ISP being not applied and no non-zero transform coefficient for the luma component of the current block, the LFNST index is not obtained.