ARITHMETIC DECODING DEVICE, IMAGE DECODING DEVICE, AND ARITHMETIC ENCODING DEVICE

摘要

To reduce the amount of processing related to coding and decoding of transform coefficients, a sub-block coefficient presence/absence flag indicating whether or not at least one non-zero transform coefficient is included is decoded for each of two or more sub-blocks obtained by dividing a unit region, and a context index of a target sub-block is derived on the basis of transform coefficient presence/absence flags each indicating whether or not a transform coefficient is 0. In accordance with the sub-block coefficient presence/absence flags of adjacent sub-blocks that are adjacent to the target sub-block, the context index of the target sub-block is derived.