ENHANCING PERCEPTUAL PERFORMANCE OF HIGH FREQUENCY RECONSTRUCTION CODING METHOD BY ADAPTIVE FILTERING

摘要

PROBLEM TO BE SOLVED: To propose a new method and a new apparatus for enhancement of audio source coding systems utilizing SBR or high frequency reconstruction (HFR) as a related method. SOLUTION: It utilizes adaptive filtering to reduce artifacts due to different tonal characteristics in different frequency ranges of an audio signal upon which HFR is performed. The present invention is applicable to both speech coding and natural audio coding systems. On an encoder side, high-performance detection algorithm is used to estimate a suitable quantity of spectrum whitening applicable in a decoder. The spectrum whitening changes not only with frequencies, but also with time. COPYRIGHT: (C)2006,JPO&NCIPI