| 摘要 |
PROBLEM TO BE SOLVED: To provide a technology capable of shortening a processing time of arithmetic decoding processing for switching contexts by peripheral decoding information.SOLUTION: An image decoding device divides a difference coefficient, which is a conversion coefficient of a difference signal between a decoding target image and a prediction image, into a plurality of subregions, and decodes the difference coefficient in a unit of subregion. In the image decoding device, a significant coefficient information decoding controller 1006 and an arithmetic decoding part 1001 decode significant difference coefficient information indicating that a difference coefficient value is not zero but is significant, for each difference coefficient in the subregion of the decoding target. A difference coefficient value decoding controller 1007 and the arithmetic decoding part 1001 decode the difference coefficient value in a case where the significant difference coefficient information is significant, for each pixel in the subregion of the decoding target. The significant coefficient information decoding controller 1006 decides a context for decoding the significant difference coefficient information in the subregion of the decoding target on the basis of information indicating significance of the difference coefficient in the decoded subregion. |
