Patent ID: 8208743

Claim:
An image decoding apparatus that decodes encoded image data, the encoded image data having been encoded in units of blocks and having predetermined identification data inserted therein, comprising: an identification data deletion unit that detects the identification data inserted in the encoded image data, outputs information indicating a position of the identification data, deletes the identification data inserted in the encoded image data, and outputs encoded image data from which the identification data has been deleted; a first decoding unit that decodes the encoded image data from which the identification data has been deleted by the identification data deletion unit, and outputs a code length; a determination unit that determines, based on the identification data position information output from the identification data deletion unit, whether the identification data was included in the encoded image data that has been decoded by the first decoding unit, and in case of determining that the identification data was included, adds a length of the identification data to the code length output from the first decoding unit; an accumulation unit that accumulates the code length to which the length of the identification data has been added by the determination unit, and outputs the accumulated code length in units of blocks; a registration unit that, based on the accumulated code length output from the accumulation unit, registers storage address information pertaining to encoded data that corresponds to a predetermined block in the encoded image data in a decoding table; and a second decoding unit that decodes encoded image data in a predetermined number of blocks beginning with a position of the predetermined block, in accordance with the address information registered in the decoding table by the registration unit.