US 12,316,848 B2
Image coding method based on transform, and device therefor
Moonmo Koo, Seoul (KR); Seunghwan Kim, Seoul (KR); and Jaehyun Lim, Seoul (KR)
Assigned to LG ELECTRONICS INC., Seoul (KR)
Appl. No. 17/790,907
Filed by LG ELECTRONICS INC., Seoul (KR)
PCT Filed Jan. 11, 2021, PCT No. PCT/KR2021/000339
§ 371(c)(1), (2) Date Jul. 5, 2022,
PCT Pub. No. WO2021/141472, PCT Pub. Date Jul. 15, 2021.
Prior Publication US 2023/0036126 A1, Feb. 2, 2023
Int. Cl. H04N 19/132 (2014.01); H04N 19/176 (2014.01); H04N 19/18 (2014.01); H04N 19/186 (2014.01); H04N 19/46 (2014.01)
CPC H04N 19/132 (2014.11) [H04N 19/176 (2014.11); H04N 19/18 (2014.11); H04N 19/186 (2014.11); H04N 19/46 (2014.11)] 7 Claims
OG exemplary drawing
 
1. An image decoding method performed by a decoding apparatus, comprising:
deriving transform coefficients for a current block based on residual information received from a bitstream; and
deriving residual samples for the current block based on an inverse transform for the transform coefficients,
wherein the bitstream includes flag information indicating whether a scaling list is available for a block to which a low frequency non-separable transform (LFNST) is applied,
wherein deriving the transform coefficients comprises:
determining whether the scaling list is applied for dequantization of the current block based on the flag information, an LFNST index of the current block, and a tree type of the current block; and
deriving the transform coefficients for the current block from the residual information based on the determination,
wherein based on the flag information indicating that the scaling list is not available for the block to which the LFNST is applied, the LFNST index being greater than 0, and the tree type of the current block being a single tree, the scaling list is applied to a chroma component of the current block, and
wherein based on the flag information indicating that the scaling list is not available for the block to which the LFNST is applied, the LFNST index being greater than 0, and the tree type of the current block being a dual-tree luma, the scaling list is not applied to a luma component of the current block.