| CPC H04N 19/132 (2014.11) [H04N 19/105 (2014.11); H04N 19/176 (2014.11); H04N 19/18 (2014.11)] | 4 Claims |
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1. An image decoding method performed by a decoding apparatus, the method comprising:
obtaining prediction mode information and information on transform coefficients from a bitstream;
deriving prediction samples of a target block based on the prediction mode information;
deriving transform coefficients of the target block based on the information on the transform coefficients;
deriving residual samples for the target block based on a non-separable transform for the transform coefficients; and
generating a reconstructed picture based on the prediction samples and the residual samples,
wherein the prediction samples are derived based on an intra prediction for the target block,
wherein the non-separable transform is performed based on a transform matrix,
wherein the transform matrix is a matrix including a modified basis vector,
wherein the modified basis vector includes fewer than N elements,
wherein the N is equal to a number of transform coefficients located in a region in which the non-separable transform is applied in the target block, and
wherein a size of the region in which the non-separable transform is applied in the target block is 8×8, and the N is equal to 64.
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