| CPC H04N 19/186 (2014.11) [H04N 19/132 (2014.11); H04N 19/136 (2014.11); H04N 19/176 (2014.11); H04N 19/70 (2014.11)] | 3 Claims |
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1. An image decoding method performed by a decoding apparatus, the method comprising:
obtaining image information including prediction related information and luma mapping with chroma scaling (LMCS) related information from a bitstream;
generating predicted luma samples for a current block in a current picture based on the prediction related information;
deriving LMCS codewords based on the LMCS related information;
generating mapped predicted luma samples based on the predicted luma samples and the LMCS codewords; and
generating reconstructed luma samples for the current block based on the mapped predicted luma samples,
wherein the image information includes adaptation parameter sets (APSs) and header information,
wherein each of the APSs includes type information specifying whether an APS is an LMCS APS,
wherein an LMCS data field included in the APS of which the type information specifies the LMCS APS includes the LMCS related information,
wherein the LMCS codewords are derived based on the LMCS data field,
wherein an ID value of the APS of which the type information specifies the LMCS APS is in a predetermined range,
wherein the predetermined range is 0 to 3,
wherein the header information includes LMCS related APS ID information, and
wherein the LMCS related APS ID information represents an ID of the LMCS APS.
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