	US 12,470,708 B2
	Cross-component adaptive loop filtering-based image coding apparatus and method
Jangwon Choi, Seoul (KR); and Junghak Nam, Seoul (KR)
Assigned to LG Electronics Inc., Seoul (KR)
Filed by LG Electronics Inc., Seoul (KR)
Filed on Jun. 20, 2024, as Appl. No. 18/749,310.
Application 18/749,310 is a continuation of application No. 17/639,260, granted, now 12,047,568, previously published as PCT/KR2020/011601, filed on Aug. 31, 2020.
Claims priority of provisional application 62/893,760, filed on Aug. 29, 2019.
Prior Publication US 2024/0357099 A1, Oct. 24, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 19/117 (2014.01); H04N 19/132 (2014.01); H04N 19/169 (2014.01); H04N 19/174 (2014.01); H04N 19/176 (2014.01); H04N 19/186 (2014.01); H04N 19/70 (2014.01); H04N 19/80 (2014.01)

CPC H04N 19/117 (2014.11) [H04N 19/132 (2014.11); H04N 19/174 (2014.11); H04N 19/176 (2014.11); H04N 19/186 (2014.11); H04N 19/1883 (2014.11); H04N 19/70 (2014.11); H04N 19/80 (2014.11)]

4 Claims

1. An image decoding method performed by a decoding apparatus, the method comprising:

receiving image information including prediction related information through a bitstream;

deriving an intra prediction mode of a current block in a current picture based on the prediction related information;

generating prediction luma samples and prediction chroma samples based on the intra prediction mode;

generating reconstructed luma samples and reconstructed chroma samples based on the prediction luma samples and the prediction chroma samples;

performing an adaptive loop filtering (ALF) process on the reconstructed chroma samples to generate filtered reconstructed chroma samples; and

performing a cross-component filtering process on the filtered reconstructed chroma samples to generate modified filtered reconstructed chroma samples,

wherein the image information includes information on cross-component filtering, and

the performing of the cross-component filtering process includes:

deriving a number of cross-component filters for the cross-component filtering based on the information on the cross-component filtering;

deriving cross-component filter coefficients for the cross-component filtering process based on the number of cross-component filters; and

generating the modified filtered reconstructed chroma samples based on the filtered reconstructed chroma samples and the cross-component filter coefficients,

wherein the image information includes a sequence parameter set (SPS) and slice header information,

wherein the SPS includes an ALF enabled flag related to whether the ALF process is enabled,

wherein based on a determination that a value of the ALF enabled flag is 1, the SPS includes a cross-component adaptive loop filter (CCALF) enabled flag related to whether the cross-component filtering is enabled,

wherein based on a determination that a value of the ALF enabled flag included in the SPS is 1, the slice header information includes an ALF enabled flag related to whether the ALF is enabled,

wherein based on a determination that a value of the ALF enabled flag included in the slice header information is 1 and a value of the CCALF enabled flag included in the SPS is 1, the slice header information includes information on whether the CCALF is enabled for the filtered reconstructed chroma samples, and

wherein based on a value of the information on whether the CCALF is enabled for the filtered reconstructed chroma samples being 1, the slice header information includes identification (ID) information of adaptation parameter sets (APSs) including ALF data used to derive the cross-component filter coefficients,

wherein the image information includes information on a coding tree unit, and

wherein the information on the coding tree unit includes:

information on whether a cross-component filter is applied to a Cb color component of the current block, and information on whether a cross-component filter is applied to a Cr color component of the current block, and

information on a filter set index of a cross-component filter applied to the Cb color component of the current block, and information on a filter set index of a cross-component filter applied to the Cr color component of the current block.