CPC H04N 19/122 (2014.11) [H04N 19/167 (2014.11); H04N 19/176 (2014.11); H04N 19/91 (2014.11)] | 14 Claims |
1. A video decoding method performed by a decoding apparatus, comprising:
obtaining residual information for a target block from a bitstream;
deriving transform coefficients of the target block based on the residual information;
scanning (R+1)th to Nth transform coefficients among the transform coefficients of the target block;
deriving a non-separable transform index for the target block based on the scanning of the (R+1)th to Nth transform coefficients;
deriving residual samples of the target block based on an inverse transform for the transform coefficients of the target block, wherein the inverse transform is based on the non-separable transform index;
generating a reconstructed picture based on the residual samples; and
applying a deblocking filtering on the reconstructed picture,
wherein based on a case that a non-zero transform coefficient is included in the (R+1)th to Nth transform coefficients, a value of the non-separable transform index is derived as 0,
wherein based on a case that the non-zero transform coefficient is not included in the (R+1)th to Nth transform coefficients, the inverse transform based on a non-separable transform is performed for coefficients in a top-left target area of the target block based on a transform matrix related to the non-separable transform index,
wherein a size of the transform matrix is R×N,
wherein the N is a number of samples in the top-left target area, and
wherein the R is smaller than the N.
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