DocumentCode :
1524852
Title :
ITU-T G.729 Annex A: reduced complexity 8 kb/s CS-ACELP codec for digital simultaneous voice and data
Author :
Salami, Rdwan ; Laflamme, Claude ; Bessette, Bruno ; Adoul, Jean-Pierre
Author_Institution :
Sherbrooke Univ., Que., Canada
Volume :
35
Issue :
9
fYear :
1997
fDate :
9/1/1997 12:00:00 AM
Firstpage :
56
Lastpage :
63
Abstract :
This article describes the ITU-T Recommendation G.729 Annex A (G.729A) for encoding speech signals at 8 kb/s with low complexity. G.729A is the standard speech coding algorithm for multimedia digital simultaneous voice and data (DSVD). G.729A is bitstream interoperable with G.729; that is, speech coded with G.729A can be decoded with G.729, and vice versa. Like G.729, it uses the conjugate-structure algebraic code excited linear prediction (CS-ACELP) algorithm with 10 ms frames. However, several algorithmic changes have been introduced which result in a 50 percent reduction in complexity. This article describes the algorithm introduced to achieve the low complexity goal while meeting the terms of reference. Subjective tests showed that the performance of G.729A is equivalent to both G.729 and G.726 at 32 kb/s in most operating conditions; however, it is slightly worse in the case of three tandems and in the presence of background noise. A breakdown of the complexities of both G.729 and G.729A is also given
Keywords :
algebraic codes; code standards; data communication; digital communication; linear predictive coding; multimedia communication; search problems; speech codecs; speech coding; telecommunication standards; voice communication; 8 kbit/s; CS-ACELP algorithm; G.729; G.729A; ITU-T G.729 Annex A; ITU-T Recommendation; algebraic code excited linear prediction; background noise; conjugate-structure; digital voice-data communication; multimedia digital simultaneous voice and data; performance; reduced complexity CS-ACELP codec; speech signal encoding; standard speech coding algorithm; subjective tests; Delay; Filters; ISDN; Internet telephony; Multimedia computing; Signal analysis; Speech codecs; Speech coding; Speech synthesis; Teleconferencing;
fLanguage :
English
Journal_Title :
Communications Magazine, IEEE
Publisher :
ieee
ISSN :
0163-6804
Type :
jour
DOI :
10.1109/35.620526
Filename :
620526
Link To Document :
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