Improved IMBE algorithm with adaptive forward-backward quantization
Yanxia Liang · Journal of Xidian University · 2009
A new method for updating the codebook is proposed to improve the accuracy of the adaptive backward codebook.This new algorithm sets up a line spectrum frequency coefficient's adaptive backward codebook,which implements the interpolation between the line spectrum frequency coefficients to improve the precision of the linear prediction coefficient's adaptive backward codebook.As a result,it increases the use frequency of the backward quantization and reduces the average coding rate.Objective and subjective tests show that the quality of speech synthesized by the improved method is superior to the one synthesized by the IMBE algorithm with adaptive forward-backward quantization,and as good as the one synthesized by the 2.4kbps IMBE algorithm.