| CPC H04N 19/61 (2014.11) [H04N 19/132 (2014.11); H04N 19/176 (2014.11); H04N 19/18 (2014.11); H04N 19/70 (2014.11)] | 15 Claims |
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1. A video decoding method, the method performed by an apparatus and comprising:
obtaining syntax information related to a secondary transform of a coding unit;
determining whether or not the secondary transform is applied to a transform block included in the coding unit based on the obtained syntax information;
obtaining one or more inverse transform coefficients based on the secondary transform when the secondary transform is applied to the transform block; and
obtaining a residual sample for the transform block based on the one or more inverse transform coefficients,
wherein the secondary transform is low frequency non-separable transform (LFNST),
wherein the syntax information indicates whether or not the secondary transform is applied to the coding unit and which transform kernel is used for the secondary transform,
wherein the syntax information is obtained when one or more conditions are satisfied,
wherein a condition of the one or more conditions is that an index of a last significant coefficient according to a preset scan order in a sub-block is greater than a preset value, and
wherein the sub-block is a sub-block having sub-block index 0 according to the preset scan order in the transform block.
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