FIELD: image encoding.
SUBSTANCE: image information including luminance chroma scaling (LMCS) related information and residual information is encoded. LMCS-related information includes information about bins for the LMCS. The minimum bin index and the maximum bin index are derived based on the bin information. The mapped value indexed by 0 is 0 and the mapped values indexed by indices 1 to 16 are output based on the LMCS codewords. In the display process for the prediction luminance sample, a display index is generated based on the prediction luminance samples, and a mapped prediction luminance sample is generated using the displayed value indexed by the display index. In the demapping process for luminance samples, a demapping index is derived based on the mapped values indexed by the bin indices from the minimum bin index to the maximum bin index, and a modified reconstructed luminance sample is generated using the mapped value indexed by the demapping index.
EFFECT: improved efficiency of image encoding.
3 cl, 21 dwg, 38 tbl
