| CPC H04N 19/18 (2014.11) [H04N 19/122 (2014.11); H04N 19/14 (2014.11); H04N 19/176 (2014.11); H04N 19/70 (2014.11)] | 9 Claims |
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1. An image decoding apparatus, comprising:
a memory; and
at least one processor connected to the memory, the at least one processor configured to:
derive transform coefficients for a current block based on residual information on the current block,
derive residual samples from the transform coefficients based on at least one of a low frequency non-separable transform (LFNST) or a multiple transform selection (MTS), and
generate a reconstructed picture based on the residual samples,
wherein whether to parse an MTS index related to an MTS kernel is determined based on a first variable indicating whether zero-out for the MTS is performed,
wherein whether to parse an LFNST index related to an LFNST kernel is determined based on a second variable indicating whether zero-out for the LFNST is performed,
wherein the first variable is set to an initial value of 1 in a coding unit syntax,
wherein the first variable is changed to 0 based on a color index of the current block being a luma component, and
wherein the second variable is determined regardless of the color index of the current block.
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