Title :
An 8 kb/s low complexity ACELP speech codec
Author_Institution :
Dept. of Electron. Eng, Shenzhen Univ., China
Abstract :
An 8 kb/s ACELP speech codec is proposed. The encoding algorithm is based on code-excited linear prediction (CELP) with a multi-level pulse amplitude algebraic codebook (ACELP). Only integer pitch delay is searched. There are 8 non-zero pulses with fixed amplitudes, each of +1, or +0.5, or -1 or -0.5, or zero in each algebraic codevector of length of 64 samples. An efficient nonexhaustive codebook search method is developed. The codevector´s gain and LSP frequencies are scalar quantized. An adaptive pitch prefilter before LP synthesis filter and a spectral postfilter after LP synthesis filter are adopted in the speech decoder to enhance the reconstructed speech quality
Keywords :
adaptive filters; algebraic codes; computational complexity; filtering theory; linear predictive coding; search problems; speech codecs; speech coding; 8 kbit/s; ACELP speech codec; LP synthesis filter; LSP frequencies; adaptive pitch prefilter; algebraic codevector; code-excited linear prediction; codevector gain; encoding algorithm; integer pitch delay; low complexity; multi-level pulse amplitude algebraic codebook; nonexhaustive codebook search method; reconstructed speech quality; scalar quantization; spectral postfilter; Decoding; Encoding; Filters; Frequency; Signal synthesis; Speech analysis; Speech codecs; Speech coding; Speech enhancement; Speech synthesis;
Conference_Titel :
Signal Processing, 1996., 3rd International Conference on
Conference_Location :
Beijing
Print_ISBN :
0-7803-2912-0
DOI :
10.1109/ICSIGP.1996.567352
