A low-delay CELP coder for the CCITT 16 kb/s speech coding standard

Author

Chen, Juin-Hwey ; Cox, Richard V. ; Lin, Yen-Chun ; Jayant, Nikil ; Melchner, Melvin J.

Author_Institution

AT&T Bell Lab., Murray Hill, NJ, USA

Volume

10

Issue

5

fYear

1992

fDate

6/1/1992 12:00:00 AM

Firstpage

830

Lastpage

849

Abstract

A low-delay code-excited linear prediction (LD-CELP) speech coder which is expected to be standardized in 1992 as a CCITT G Series Recommendation for universal applications of speech coding at 16 kb/s is presented. The coder achieves a one-way coding delay of less than 2 ms by making both the LPC predictor and the excitation gain backward-adaptive and by using a small excitation vector size of five samples. The official CCITT laboratory tests revealed that the speech quality of this 16 kb/s LD-CELP coder is either equivalent to or better than that of the CCITT G.721 standard 32-kb/s ADPCM coder for almost all conditions tested. A description of the LD-CELP algorithm, its implementation on the DSP32C for CCITT testing, and performance results from these tests are presented

Keywords

codecs; delays; encoding; filtering and prediction theory; speech analysis and processing; speech intelligibility; standards; 16 kbit/s; CCITT G Series Recommendation; DSP32C; LD-CELP algorithm; LPC predictor; backward adaptive excitation gain; code-excited linear prediction; coding delay; excitation vector size; laboratory tests; low delay; speech coder; speech coding standard; speech quality; Bit rate; Code standards; Delay; Linear predictive coding; Performance loss; Phase change materials; Speech analysis; Speech coding; Testing; Vectors;

fLanguage

English

Journal_Title

Selected Areas in Communications, IEEE Journal on

Publisher

ieee

ISSN

0733-8716

Type

jour

DOI

10.1109/49.138988

Filename

138988