| CPC H04N 19/44 (2014.11) [H04N 19/176 (2014.11); H04N 19/619 (2014.11)] | 3 Claims |

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1. An image decoding device, wherein the image decoding device:
generates a prediction residual signal by inverse transform;
controls a method of decoding a secondary transform index of a target block according to information indicating a position where a non-zero coefficient is generated in the target block and to information indicating whether or not the target block is dual tree, and
omits decoding the secondary transform index of the target block in a case where the information indicating the position where the non-zero coefficient is generated in the target block indicates a coefficient position of a direct current component of the target block.
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