Patent ID: 7486830

Claim:
A decoding apparatus for decoding compression data comprising: a reference value extracting unit that extracts, from the compression data, quantization indices Q(c, i+m,j+n)(−M≦m≦M, −N≦n≦N) for a quantization index Q(c, i, j) to be processed of multiple quantization indexes Q(c, i, j) to be processed, wherein c denotes a transform coefficient, i and j denote a position of each transform coefficient and M, and N denote integers; and a decoded data generating unit that generates a dequantization value Ry(c, i, j) of multiple dequantization values Ry(c, i, j), the dequantization value Ry(c, i, j) corresponding to each quantization index Q(c, i, j) to be processed based on each quantization index Q(c, i, j) to be processed and the corresponding extracted quantization indices Q(c, i+m, j+n)(−M≦m≦M, −N≦n≦N); an inverse transforming unit that generates decoded data based on the dequantization values Ry(c, i, j) wherein different filters are applied when the decoded data generating unit generates the dequantization value Ry(c, i, j), based on whether the transform coefficient corresponds to an AC component or a DC component.