IMAGE DECODING APPARATUS AND IMAGE DECODING METHOD

PROBLEM TO BE SOLVED: To provide an image decoding apparatus which is applicable to high-bit precision by suppressing circuit scale and memory capacity as conventional specification compliance. SOLUTION: The image decoding apparatus 100 includes: a variable length decoding part 2 which performs variable length decoding of encoded data; a dequantization and inverse orthogonal transformation part 13 which dequantizes and performs inverse orthogonal transformation to output of the variable length decoding part 2 to generate a difference pixel value with 11-bit precision; an image data conversion part 11 which converts the difference pixel value with 11-bit precision into the one with 9-bit precision; a memory 81 which holds a reference image with 8-bit precision; an addition part 4 which adds the reference image and the difference pixel value with 9-bit precision together to be held in the memory 81 as a reference image; an addition part 14 adds the reference image to be held in the memory 81 and the difference pixel value with 11-bit precision together to generate image data with 10-bit precision; and a memory 82 which holds difference of 2 bits between the image data with 10-bit precision and the image data with 8-bit precision. COPYRIGHT: (C)2009,JPO&INPIT