A 16 kbit/s wideband CELP coder using MEL-generalized cepstral analysis and its subjective evaluation
Kazuhito Koishida, Gou Hirabayashi, Keiichi Tokuda, Takao Kobayashi · 1998
We have proposed a wideband CELP coder, called MGC-CELP, which provides high quality speech by utilizing mel-generalized cepstral (MGC) analysis instead of linear prediction (LP). In this paper, we investigate the performance of the wideband MGCCELP coder at 16 kbit/s in terms of short-term predictor order, i.e., order of MGC analysis. Subjective tests show that the MGCCELP coder with a predictor of order 20 gives better performance than ITU-T G.722 at 64 kbit/s. It is also found that the MGCCELP coder with 12th order achieves comparable quality to the 64 kbit/s G.722, and outperforms the 16 kbit/s conventional CELP coder using 20th-order LP analysis under the same conditions. 1. INTRODUCTION Recently several schemes for high-quality wideband speech coding at low bit rates have been developed. Most of the work in this field uses either transform/subband coding or CELP (Code Excited Linear Prediction) coding. At the bit rates around 16 kbit/s, CELP coding has received much attention s...