IMAGE ENCODER, IMAGE ENCODING METHOD, IMAGE DECODER, AND IMAGE DECODING METHOD

摘要

PROBLEM TO BE SOLVED: To reduce the capacity of a frame memory without degrading encoding efficiency by storing an image in a frame memory by adaptively compressing when a pixel bit accuracy is expanded.

SOLUTION: An image decoder converts the bit accuracy of each pixel of the input image consisting of pixels of N-bit accuracy into (N+M) bit accuracy which is M-bit larger. It includes an adaptive bit length converter 312 which converts the bit accuracy of each pixel of a decoded image of (N+M) bit accuracy into N-bit accuracy by selectively using a plurality of conversion methods, being different from each other, a frame memory 308 which preserves the decoded image of N-bit accuracy as a reference image, and a pixel bit length inverse converter 313 which converts the bit accuracy of each pixel of the reference image of N-bit accuracy that has been read from the frame memory 308 into (N+M) bit accuracy which is M-bit larger according to the conversion method.

COPYRIGHT: (C)2012,JPO&INPIT