A wideband CELP speech coder at 16 kbit/s based on mel-generalized cepstral analysis

This paper proposes a wideband CELP coder using frequency warping. Instead of linear prediction, the proposed coder adopts the mel-generalized cepstral analysis, and encodes the fullband of the speech signal through a warped frequency scale. It is shown that the subjective quality of the proposed coder at 16 kbit/s is better than that of the ITU-T G.722 at 64 kbit/s. Furthermore, the proposed coder gives a much smaller difference in performance for male and female speakers than the conventional CELP coder. These results indicate that the frequency warping makes a large contribution to the improvement of the subjective quality for wideband speech coding