| 摘要 |
PROBLEM TO BE SOLVED: To more efficiently decode image data by eliminating redundancy in a block, in comparison with the conventional technology. SOLUTION: A quantized AC coefficient of a predicted block scaled, by using the ratio of a quantization step size of a current block (C) to a quantization step size of the predicted block is added to the AC coefficient data of a quantized two-dimensional column coefficient, to predictively decode the quantized AC coefficient of the current block (C), with respect to the quantized AC coefficient of the predicted block. The quantized AC coefficient of the predictively decoded current block (C) is stored, the quantized AC coefficient of the predictively decoded current block is subjected to inverse quantization, and the inversely quantized AC coefficient is subjected to inverse DCT transformation. The stored quantized AC coefficient is used as the quantized AC coefficient of the selected predicted block, when decoding a block to be decoded which is delayed more than the current block (C). |
