WEIGHT CODE BOOK AND ITS GENERATING METHOD, SETTING METHOD FOR INITIAL VALUE OF MA PREDICTION COEFFICIENT IN LEARNING IN CODE BOOK DESIGNING, ENCODING METHOD AND DECODING METHOD FOR SOUND SIGNAL, COMPUTER-READABLE STORAGE MEDIUM STORING ENCODING PROGRAM AND COMPUTER- READABLE STORAGE MEDIUM STORING DECORDING PROGRAM

摘要

PROBLEM TO BE SOLVED: To make suppressible deterioration in the sound quality of a relatively-low-sound- pressure part of a decoded sound signal by setting respective elements of a weight code book by using a distance scale determined by taking human sound pressure sense characteristics into account and encoding a sound signal by using the weight code book which is thus generated. ;SOLUTION: In order to calculate the distortion (d) of a reproduced sound candidate (y) while taking auditory weighting into consideration, a distortion calculation part 1-6 inputs the reproduced sound candidate (d) outputted from a composing filter after passing it through an auditory weighting filter 2-2 and also inputs an input sound (x) to the distance calculation part 2-4 after passing it through an auditory weighting filter 2-3. The auditory weighting filter 2-2 has a linear prediction parameter (a) as a coefficient, converts the reproduced sound candidate (y) into a reproduced sound candidate yw with auditory weight, and outputs it to the distance calculation part 2-4. The auditory weighting filter 2-3 is a filter which uses a fixed coefficient, and converts an input sound (x) into an input sound xw with auditory weight and outputs it to the distance calculation part 2-4.;COPYRIGHT: (C)2000,JPO