US Patent 8005306 Decoding apparatus, inverse quantization method, and computer readable medium

A decoding apparatus includes a classification section, a distribution-information generation section and an inverse-quantization-value generation section. The classification section classifies quantization indices contained in input code data into a plurality of groups. The distribution-information generation section generates distribution information of the quantization indices for each group, based on the quantization indices classified by the classification section. The inverse-quantization-value generation section generates inverse quantization values, which correspond to the respective quantization indices, based on the distribution information generated by the distribution-information generation section.