Stephen D. Voran and Andrew A. Catellier

Abstract: 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.

Keywords: databases; speech coding; decoding; Testing; Payloads; speech

Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

For questions or information on this or any other NTIA scientific publication, contact the ITS Publications Office at ITSinfo@ntia.gov or 303-497-3572.

Back to Search Results