A real-time wideband CELP coder for a videophone application

Abstract

In this paper we present an algorithm for the coding of wideband (7 kHz) speech signals at 16 kbps using code excited linear prediction (CELP), primarily intended for use in audio-visual coding systems (e.g., videotelephony) in the ISDN network, or other telecommunication equipment using loudspeaker sound. The algorithm is a full-band approach and much effort has been put into reducing the computational complexity. This has led to a real-time implementation of the present algorithm on a single TMS320C31 DSP (encoder+decoder). Through a formal subjective evaluation we have demonstrated a performance comparable to the CCITT Rec. G.722 subband coder at 64 kbps.<>