| CPC H04N 19/44 (2014.11) [H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/625 (2014.11); H04N 19/70 (2014.11)] | 9 Claims |
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1. A method for decoding a video signal, comprising:
deriving an intra prediction mode of a current block;
parsing a syntax element related to a secondary transform of the current block, the syntax element including information whether to apply the secondary transform to the current block and information about which secondary transform kernel is applied to the current block;
determining a secondary transform kernel set among a plurality of secondary transform kernel sets based on the intra prediction mode when the syntax element specifies that the secondary transform is applied to the current block, wherein each of a plurality of intra prediction modes corresponds to one of the plurality of secondary transform kernel sets, and each of the plurality of secondary transform kernel sets comprises two transform kernels;
determining a secondary transform kernel among the two transform kernels included in the secondary transform kernel set, based on the syntax element;
obtaining transform coefficients of the current block by performing entropy decoding and inverse quantization;
obtaining a secondary inverse-transformed block of the current block by performing a secondary inverse transform on transform coefficients of the current block based on the secondary transform kernel;
obtaining a residual block of the current block by performing a primary inverse transform on the secondary inverse-transformed block based on a primary transform kernel;
generating a prediction block of the current block based on the intra prediction mode; and
reconstructing the current block based on the prediction block and the residual block, and
wherein a number of the plurality of intra prediction modes is 67 and a number of the plurality of secondary transform kernel sets is 4.
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