A robust low-delay CELP speech coder at 16 kbits/s

A candidate algorithm for the new CCITT 16-kb/s speech coding standard is presented. This algorithm is based on backward-adaptive CELP (code-excited linear prediction) where the predictor and the excitation gain are updated by analyzing previously quantized signals. The only information transmitted is the excitation vector with a size as small as five samples so as to achieve a one-way coding delay of less than 2 ms. With a clear channel, this 16-kb/s coder slightly outperformed the CCITT standard 32 kb/s ADPCM (adaptive differential pulse code modulation) (G.721) in speech quality as measured by the mean opinion score (MOS). With noisy channels, the coder scored slightly higher than G.721 fora bit-error rate of 10/sup -2/ and significantly higher (by a margin of 0.5) for bit-error rate of 10/sup -3/. >

[1]  N. Jayant.  Adaptive quantization with a one-word memory , 1973 .

[2]  David J. Goodman,et al.  A Robust Adaptive Quantizer , 1975, IEEE Trans. Commun..

[3]  P. Noll,et al.  Adaptive transform coding of speech signals , 1977 .

[4]  Thomas P. Barnwell,et al.  Recursive windowing for generating autocorrelation coefficients for LPC analysis , 1981 .

[5]  Bishnu S. Atal,et al.  A new model of LPC excitation for producing natural-sounding speech at low bit rates , 1982, ICASSP.

[6]  Bishnu S. Atal.  Predictive Coding of Speech at Low Bit Rates , 1982, IEEE Trans. Commun..

[7]  Manfred R. Schroeder,et al.  Code-excited linear prediction(CELP): High-quality speech at very low bit rates , 1985, ICASSP '85. IEEE International Conference on Acoustics, Speech, and Signal Processing.

[8]  Nuggehally Sampath Jayant,et al.  Adaptive postfiltering of 16 kb/s-ADPCM speech , 1986, ICASSP '86. IEEE International Conference on Acoustics, Speech, and Signal Processing.

[9]  Isabel Trancoso,et al.  Efficient procedures for finding the optimum innovation in stochastic coders , 1986, ICASSP '86. IEEE International Conference on Acoustics, Speech, and Signal Processing.

[10]  Frank K. Soong,et al.  A high quality subband speech coder with backward adaptive predictor and optimal time-frequency bit assignment , 1986, ICASSP '86. IEEE International Conference on Acoustics, Speech, and Signal Processing.

[11]  Allen Gersho,et al.  Real-time vector APC speech coding at 4800 bps with adaptive postfiltering , 1987, ICASSP '87. IEEE International Conference on Acoustics, Speech, and Signal Processing.

[12]  Yukou Mochida,et al.  A 16 kbps ADPCM with multi-quantizer (ADPCM-MQ) codec and its implementation by digital signal processor , 1987, ICASSP '87. IEEE International Conference on Acoustics, Speech, and Signal Processing.

[13]  K. Zeger,et al.  Zero redundancy channel coding in vector quantisation , 1987 .

[14]  Allen Gersho,et al.  Gain-Adaptive Vector Quantization with Application to Speech Coding , 1987, IEEE Trans. Commun..

[15]  Jerry D. Gibson,et al.  Backward adaptive tree coding of speech at 16 kbps , 1988, ICASSP-88., International Conference on Acoustics, Speech, and Signal Processing.

[16]  V. Cuperman,et al.  A vector ADPCM analysis-by-synthesis configuration for 16 kbit/s speech coding , 1988, IEEE Global Telecommunications Conference and Exhibition. Communications for the Information Age.

[17]  Yair Shoham,et al.  New directions in subband coding , 1988, IEEE J. Sel. Areas Commun..

[18]  P. Kabal,et al.  A low delay 16 kbits/sec speech coder , 1988, ICASSP-88., International Conference on Acoustics, Speech, and Signal Processing.

[19]  Daniele Sereno,et al.  A 2 ms delay CELP coder , 1989, International Conference on Acoustics, Speech, and Signal Processing,.