CPC H04N 19/60 (2014.11) [H04N 19/124 (2014.11); H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/18 (2014.11); H04N 19/70 (2014.11); H04N 19/96 (2014.11)] | 12 Claims |
1. An image decoding method performed by a decoding apparatus, the method comprising:
receiving residual information and a transform index from a bitstream;
deriving transform coefficients for a target block based on the residual information;
deriving modified transform coefficients based on an inverse non-separable transform for the transform coefficients; and
deriving residual samples for the target block based on an inverse primary transform for the modified transform coefficients,
wherein the inverse non-separable transform is performed based on a transform kernel matrix related to the transform index among transform kernel matrices included in a transform set,
wherein the transform index is decoded based on a context adaptive binary arithmetic coding (CABAC) and by:
deriving context information of a syntax element for the transform index;
decoding, based on the context information, bins of the syntax element for the transform index, the bins including a first bin and a second bind; and
deriving, based on the decoded bins, a value of the syntax element for the transform index,
wherein (i) based on a tree type of the target block being a dual tree type, the first bin of the syntax element for the transform index is derived based on a first context information, and (ii) based on the tree type of the target block being a single tree type, the first bin of the syntax element for the transform index is derived based on a second context information, and
wherein the first context information and the second context information are different from each other.
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