CPC H04N 19/105 (2014.11) [H04N 19/132 (2014.11); H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/186 (2014.11); H04N 19/46 (2014.11)] | 16 Claims |
1. A video decoding method for performing intra prediction for a current block, which is performed by a video decoding apparatus, the method comprising:
obtaining luma mapping chroma scaling (LMCS) parameters, a first flag indicating whether LMCS is activated, and a second flag indicating whether chroma residual scaling is activated, from a bitstream, wherein the LMCS converts the luma signals between an original area and a mapping area of a luma signal;
generating luma residual signals and scaled chroma residual signals from the bitstream;
generating a luma mapping function of converting a dynamic area of the luma signals by using the LMCS parameters when the first flag is activated, wherein the luma mapping function indicates a first function of converting the luma signals into the mapping area or a second function of inversely converting the mapped luma signals into the original area;
generating luma reference samples for the current block by using the luma mapping function when neighboring restoration samples of the current block are not available;
generating luma predicted samples by performing intra prediction for the current block based on the luma reference samples; and
generating luma restoration samples by adding the luma predicted samples and the luma residual signals.
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