IMAGE DECODING DEVICE, IMAGE DECODING METHOD, IMAGE DECODING PROGRAM, RECEIVING DEVICE, RECEIVING METHOD, AND RECEIVING PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide an image decoding technology by a context index calculation method that can be processed in parallel and has a small amount of calculations.SOLUTION: In an image decoding device dividing a difference coefficient that is a conversion coefficient of a difference signal between an image of a decoding target and a prediction image into a plurality of sub blocks and decoding the difference coefficient in a sub block unit, a context deriving part derives different indexes between the case that significant sub block information of a decoded sub block adjacent in a horizontal direction is 0 and significant sub block information of a decoded sub block adjacent in the vertical direction is 0, and the case that the significant sub block information of the decoded sub block adjacent in the horizontal direction is 1 and the significant sub block information of the decoded sub block adjacent in the vertical direction is 1.