Multiple-Description Speech Coding Using Speech-Polarity Decomposition

We present and evaluate a new multiple-description coding extension to the international standard for pulse code modulation speech coding (ITU-T Rec. G.711). This extension is inserted between the G.711 encoder and decoder. It uses speech-polarity decomposition to spread the speech signal across two channels thus increasing robustness to channel losses. When both channels deliver their payloads the extension becomes transparent and bit-exact G.711 speech samples are produced-there is no quality penalty. Due to low inter-channel redundancy, block coding, and entropy coding, the average total speech payload bit-rate is no greater than the 64 kbps rate of conventional G.711-there is no rate penalty. When either channel fails to deliver, the remaining channel still produces intelligible speech with moderately reduced quality thanks to a compressed sine-pulse fill-in algorithm. We are not aware of any other viable multiple-description coding extension that simultaneously meets the opposing goals of no quality penalty and no rate penalty.