Patent ID: 8421653

Claim:
An information processing apparatus for converting fixed-length codes into variable-length codes, each of the fixed-length codes being generated by performing fixed length encoding, by using one of a plurality of fixed length encoding methods, on each divided image obtained by dividing an original image, comprising: an input unit configured to obtain each of the fixed-length codes as an input code; a determination unit configured to determine a fixed length encoding method of the input code; a conversion unit configured to perform variable length encoding, by using a first variable length encoding method, on the input code encoded by a first fixed length encoding method, and perform variable length encoding, by using a second variable length encoding method, on the input code encoded by a second fixed length encoding method; and an output unit configured to output a variable-length code obtained by said conversion unit, wherein the fixed-length code encoded by the first fixed length encoding method includes a plurality of fields; and the conversion unit is further configured to perform the variable length encoding as the first variable length encoding method by comparing a coefficient in the field included in the input code with a coefficient in a corresponding field included in a compared code, wherein the compared code is generated by performing fixed length encoding on the divided image by the first fixed length encoding method.