A 16, 24, 32 kbit/s wideband speech codec based on ATCELP
P. Combescure, J. Schnitzler, Katrin Fischer, R. Kircherr, Claude Lamblin, Alain Le Guyader, D. Massalaux, Catherine Quinquis, Joachim Stegmann, Peter Vary · 1999
This paper describes a combined adaptive transform codec (ATC) and code-excited linear prediction (CELP) algorithm, called ATCELP, for the compression of wideband (7 kHz) signals. The CELP algorithm applies mainly to speech, whereas the ATC mode is selected for music and noise signals. We propose a switching scheme between CELP and ATC mode and describe a frame erasure concealment technique. Subjective listening tests have shown that the ATCELP codec at bit rates of 16, 24 and 32 kbit/s achieved performances close to those of the CCITT G.722 at 48, 56 and 64 kbit/s, respectively, at most operating conditions.