A New Multistage Search of Algebraic CELP Codebooks Based on Trellis Coding

Mohammed HALIMI  Abdellah KADDAI  Messaoud BENGHERABI  

Publication
IEICE TRANSACTIONS on Information and Systems   Vol.E86-D   No.3   pp.406-411
Publication Date: 2003/03/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8532
Type of Manuscript: Special Section PAPER (Special Issue on Speech Information Processing)
Category: Speech and Audio Coding
Keyword: 
trellis,  algebraic codebook,  speech coding,  CELP,  G.729,  

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Summary: 
This paper proposes a new multistage technique of algebraic codebook in CELP coders called Trellis Search inspired from the Trellis Coded Quantization (TCQ). This search technique is implemented into the fixed codebook of the standard G.729 for objective evaluation on a large corpus of a testing speech database. Simulations results show that in terms of computer execution time the proposed search scheme reduces the codebook search by approximately 23% compared to the time of focused search used in the standard G.729. This yields to a reduction of about 8% in the computer execution time of the coder at the cost of a slight degradation of speech quality but perceptually not noticeable. Moreover, this new technique shows better speech quality than the G.729A at the expense of a higher complexity.