Title :
8Kbit/s low delay speech coding algorithm with adaptive codebook
Author :
Shuhong, Wu ; Gang, Zhang
Author_Institution :
Comput. & Software Coll., Taiyuan Univ. of Technol., Taiyuan, China
Abstract :
This paper makes improvement in G.728 algorithm aiming at reducing coding rate and presents an 8 Kbit/s speech coding algorithm whose delay is 2.5 ms. The size of frame which is 5 samples in G.728 is extended to 20 samples. Adaptive codebook is introduced, which is composed of the recent excitation.20 dimensions normalized fixed codebook is adopted for the proposed algorithm. The exact gain of adaptive and fixed codeword are calculated and quantized. Fixed quantization is used in adaptive codebook and adaptive quantization is used in fixed codebook. The size of adaptive and fixed codeword are both 128 and their gain are both 8. The whole search mode is used to obtain the best excitation in algorithm. New algorithm´s coding rate is only half of G.728 and has only 2.5 ms delay. Testing with the average segment SNR and Perceptual Evaluation of Speech Quality (PESQ), the improved algorithm is close to G.728 in speech coding quality. And it achieves desirable balance in coding rate, delay time and coding quality.
Keywords :
quantisation (signal); speech coding; G.728 algorithm; adaptive codebook; adaptive quantization; bit rate 8 kbit/s; coding rate; fixed quantization; gain quantization; perceptual evaluation of speech quality; speech coding; Adaptive filters; Communication system control; Delay effects; Educational institutions; Paper technology; Quantization; Software algorithms; Speech analysis; Speech coding; Technology management; Low delay speech coding algorithm; Perceptual Evaluation of Speech Quality (PESQ); adaptive codebook; gain quantization;
Conference_Titel :
Computing, Communication, Control, and Management, 2009. CCCM 2009. ISECS International Colloquium on
Conference_Location :
Sanya
Print_ISBN :
978-1-4244-4247-8
DOI :
10.1109/CCCM.2009.5270453