IMAGE DECODING METHOD, IMAGE DECODER, AND RECORDING MEDIUM IMAGE DECODING PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide an efficient decoder that can improve coding efficiency of mode information and reduce the entire code quantity of one frame. SOLUTION: In the case of decoding a digital image from a coded image signal for every two-dimensional block, a demultiplexer means 21 of the image decoder demultiplexes a code word with respect to a coding mode and a code word with respect to block data from the coded image signal and a mode information decoding means 22 recovers the coding mode of a decoded block around a decoding target block from a code word with respect to the coding mode or selects a code word table where code words are decided in cross-reference with combinations of tentative mode information sets in place of mode information of surrounding blocks and acting like mode information of the surrounding blocks when the surrounding blocks of a coded target block is outside an image to recover the coding mode of the decoding target block.