| CPC H04N 19/132 (2014.11) [H04N 19/176 (2014.11); H04N 19/18 (2014.11); H04N 19/46 (2014.11)] | 9 Claims |
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1. An image decoding method performed by a decoding apparatus, comprising:
receiving residual information from a bitstream;
deriving transform coefficients for a current block based on the residual information;
determining whether to parse a multiple transform selection (MTS) index for applying an MTS to the current block;
deriving residual samples for the current block by applying the MTS to the current block based on the MTS index; and
generating a reconstructed picture based on the residual samples,
wherein whether to parse the MTS index is determined based on a flag value related to whether at least one non-zero transform coefficient for a luma component of the current block is present,
wherein based on the flag value being 0, the MTS index is not parsed,
wherein whether to parse the MTS index is determined based on a first variable indicating whether zero-out for the MTS is performed,
wherein the first variable is set to an initial value equal to 1 in a coding unit syntax,
wherein, based on a case where the at least one non-zero transform coefficient is present in a second region other than a first region at a top-left of the current block and a color index of the current block indicates a luma component, the first variable is changed to 0 in a residual coding syntax, and
wherein the MTS index is configured in the coding unit syntax.
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