Patent ID: 11962767
Assignee: LG ELECTRONICS INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method for image decoding performed by a decoding apparatus, the method comprising:
acquiring image information including prediction-related information and residual information through a bit stream;
deriving transform coefficients based on the residual information;
generating residual samples based on the transform coefficients;
generating prediction samples based on the prediction-related information; and
generating reconstructed samples based on the prediction samples and the residual samples, the reconstructed samples including reconstructed luma samples and reconstructed chroma samples;
deriving adaptive loop filter (ALF) coefficients for an ALF process of the reconstructed chroma samples;
generating filtered reconstructed chroma samples based on the reconstructed chroma samples and the ALF filter coefficients;
deriving cross-component filter coefficients for cross-component filtering; and
generating modified filtered reconstructed chroma samples based on the reconstructed luma samples, 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,
the SPS includes ALF enabled flag related to whether the ALF process is enabled,
based on a value of the ALF enabled flag being 1, the SPS includes a cross-component adaptive loop filter (CCALF) enabled flag related to whether the cross-component filtering is available,
based on a determination that a value of the ALF enabled flag in the SPS is 1, the slice header information includes an ALF enabled flag related to whether the ALF is enabled,
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
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 an adaptation parameter set (APS) associated with the CCALF for the filtered reconstructed chroma samples,
ALF data included in the APS includes information related to a number of the cross-component filters for the Cb color component and information related to a number of cross-component filters for the Cr component,
based on the information related to the number of the cross-component filters for the Cb color component, the ALF data includes information on absolute values of the cross-component filter coefficients for the Cb color component and information on signs of the cross-component filter coefficients for the Cb color component, and
based on information related to the number of the cross-component filters for the Cr color component, the ALF data includes information on absolute values of the cross-component filter coefficients for the Cr color component and information on signs of the cross-component filter coefficients for the Cr color component.