Variable length code decoding apparatus and method with variation in timing of extracting bit string to be decoded depending on code word

Abstract

A variable length code decoding apparatus according to the present invention includes: an extracting unit which extracts a bit string from a beginning of a bit stream; a first storage unit for storing a plurality of code words in which one piece of data has been coded, and decoded data and code lengths respectively corresponding to the code words; a second storage unit for storing a plurality of code words in which two or more pieces of data have been coded, and decoded data and code lengths respectively corresponding to the code words; a first judging unit which judges whether one of the code words stored in the first storage unit is included in the extracted bit string, and, when judged as being included, outputs the decoded data and the code length of the code word; and a second judging unit which judges whether a code word stored in the second storage unit is included in the extracted bit string, and when judged as being included, outputs the decoded data and the code length of the code word, wherein the extracting unit extracts the bit string to be decoded next in the same cycle as a cycle in which the judgment was made by the first judging unit, and extracts the bit string to be decoded next in a cycle following the cycle in which the judgment was made by the second judging unit.