SCALABLE ENCODING METHOD AND DEVICE, SCALABLE DECODING METHOD AND DEVICE, PROGRAM THEREOF, AND RECORDING MEDIUM

摘要

Provided is a scalable encoding method which divides an image signal into hierarchies of different spatial resolutions, subjects each frame of each hierarchy to a prediction process, subjects a prediction difference obtained by the prediction process to a first conversion process, and subjects a low-frequency component of a conversion coefficient obtained by the first conversion process to a second conversion process. The method includes a step for setting a size of one conversion in the second conversion process and a step for encoding the mode information indicating the set second conversion process size and adding it to the encoded information, so as to adaptively change the second conversion process size.