Patent ID: 11968401
Assignee: LG ELECTRONICS INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. An image decoding method performed by a decoding apparatus, the method comprising:
obtaining image information including prediction mode information and residual information through a bitstream;
deriving a prediction mode of a current block based on the prediction mode information;
deriving prediction samples based on the prediction mode;
deriving residual samples based on the residual information;
generating reconstructed samples based on the prediction samples and the residual samples;
deriving filter coefficients for an adaptive loop filter (ALF) on the reconstructed samples; and
generating modified reconstructed samples based on the reconstructed samples and the filter coefficients,
wherein the image information includes a sequence parameter set (SPS), slice header information and a first adaptation parameter set (APS) comprising an ALF data field,
wherein the ALF data field includes ALF parameters used for deriving the filter coefficients,
wherein the SPS includes ALF enabled flag information related to whether the ALF is enabled,
wherein the slice header information includes ALF enabled flag information related to whether the ALF is enabled in a slice based on the ALF enabled flag information in the SPS,
wherein the slice header information includes ALF related APS IDs number information based on the ALF enabled flag information in the slice header,
wherein a number of ALF related APS IDs is derived based on a value of the ALF related APS IDs number information, and
wherein ALF related APS ID syntax elements of which number is equal to the number of ALF related APS IDs are included in the slice header information.