A Method of Optimizing LD-CELP's Gain

摘要

This paper combines the Jayant adaptive quantization and G.728's gain prediction to propose a scheme fit for designing gain coodbook of LD-CELP, in which the exact gain value was adaptively predicted and quantized. In this method, for adaptive quantization gain of 3 bits and 4 bits, the SNR have been increased by 0.5 and 6 dB separately than that of G.728. If adopting 4 bits adaptive quantization and the shape codebook of 64 codevectors, the G.728' complexity could be reduced by 20% while SNR had 1 dB improvement.