Patent ID: 9716895
Date: 2017-07-25
CPC Classifications: H04N

Claim:
1. An image coding apparatus comprising: a division unit configured to divide an input image into a plurality of blocks, at least one of the blocks being divided into at least four subblocks, the subblocks included in a block being represented by a quadtree structure; a decision unit configured to decide respective quantization parameters of at least four subblocks represented by the quadtree structure; an acquisition unit configured to acquire a first difference value between a first quantization parameter of a first subblock of the subblocks and a second quantization parameter of a second subblock of the subblocks, the first subblock to be coded before the second subblock and the second subblock being arranged at the right of the first subblock, and to acquire a second difference value between a third quantization parameter of a third subblock of the subblocks and a value corresponding to an average of quantization parameters of subblocks which are to be coded before the third subblock, the third subblock being arranged at the bottom right of the first subblock; and a coding unit configured to code the first difference value and the second difference value.