US 12,225,214 B2
Luma mapping and chroma scaling-based video or image coding
Jie Zhao, Seoul (KR); and Seunghwan Kim, Seoul (KR)
Assigned to LG ELECTRONICS INC., Seoul (KR)
Filed by LG ELECTRONICS INC., Seoul (KR)
Filed on Nov. 29, 2022, as Appl. No. 18/071,156.
Application 18/071,156 is a continuation of application No. 17/566,620, filed on Dec. 30, 2021, granted, now 11,539,967.
Application 17/566,620 is a continuation of application No. PCT/KR2020/008808, filed on Jul. 6, 2020.
Claims priority of provisional application 62/871,068, filed on Jul. 5, 2019.
Prior Publication US 2023/0123604 A1, Apr. 20, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 19/186 (2014.01); H04N 19/105 (2014.01); H04N 19/176 (2014.01); H04N 19/30 (2014.01); H04N 19/593 (2014.01)
CPC H04N 19/186 (2014.11) [H04N 19/105 (2014.11); H04N 19/176 (2014.11); H04N 19/30 (2014.11); H04N 19/593 (2014.11)] 3 Claims
OG exemplary drawing
 
1. An image decoding method performed by a decoding apparatus, the method comprising:
obtaining image information including prediction related information and residual information from a bitstream;
deriving an inter prediction mode for a current block based on the prediction related information;
deriving motion information for the current block based on the inter prediction mode;
generating prediction luma samples and prediction chroma samples based on the motion information for the current block;
generating mapped prediction luma samples based on mapping process for the prediction luma samples;
generating residual luma samples and residual chroma samples based on the residual information;
generating reconstructed luma samples based on the mapped prediction luma samples and the residual luma samples;
deriving a chroma residual scaling factor based on the reconstructed luma samples; and
generating reconstructed chroma samples based on the prediction chroma samples and scaled residual chroma samples,
wherein the image information includes luma mapping with chroma scaling (LMCS) related information, information on an absolute value of a chroma residual scaling delta value and information on a sign of the chroma residual scaling delta value,
wherein the LMCS related information includes information on LMCS codewords, information related to a minimum bin index and information related to a maximum bin index,
wherein LMCS codewords are derived based on the information on the LMCS codewords,
wherein an inverse scaling index is derived based on the information related to the minimum bin index, the information related to the maximum bin index and the reconstructed luma samples,
wherein the chroma residual scaling factor is derived based on the LMCS codewords, the inverse scaling index, the information on the absolute value of the chroma residual scaling delta value and the information on the sign of the chroma residual scaling delta value, and
wherein the scaled residual chroma samples are generated based on the residual chroma samples and the chroma residual scaling factor.