Patent ID: 7289953
Filing Date: 2007-10-30
Classification: G10L

Abstract:
1. A speech encoder comprising: an LPC synthesizer that obtains synthesized speech by filtering an adaptive excitation vector and a stochastic excitation vector stored in an adaptive codebook and in a stochastic codebook using LPC coefficients obtained from input speech; a gain calculator that calculates gains of said adaptive excitation vector and said stochastic excitation vector and searches code of the adaptive excitation vector and code of the stochastic excitation vector by comparing distortions between said input speech and said synthesized speech obtained using said adaptive excitation vector and said stochastic excitation vector; and a parameter coder that performs predictive coding of gains using said adaptive excitation vector and said stochastic excitation vector corresponding to the codes obtained, wherein said parameter coder comprises a prediction coefficient adjuster that adjusts at least one prediction coefficient used for said predictive coding according to at least one state of at least one previous subframe.