基于ACELP和TCX的嵌入式宽带语音编码器

Embedded wideband speech codec based on ACELP and TCX

为了应对以分组交换为基础的IP网络上出现的分组丢失和分组延时现象,该文提出了一种嵌入式宽带语音编码器。该编码器是国际电信联盟标准化组织(ITU-T)G.VBR候选方案之一。编码器可形成8~32kbit/s 5层具有嵌入式结构的码流,其中,前3层的码流利用嵌入式代数码激励线性预测(algebraic code-excited linearprediction,ACELP)编码技术生成,后2层的码流利用变换码激励(transform coded excitation,TCX)编码技术生成。当出现帧丢失时,利用了先前帧的语音分类信息和参数编码信息来恢复丢失帧的语音信号。本套编码器经过ITU-T组织的测试,多项指标已经达到了ITU-T对G.VBR提出的参考要求。

Packet loss and packet delays due to packet switching on IP nets affect speech quality.This paper presents an embedded wideband speech codec which is one candidate for the G.VBR proposed by the telecommunication standardization sector(ITU-T).The codec divides an embedded bit-stream into five layers with bit rates from 8 kbit/s to 32 kbit/s.The first three layers are coded using the algebraic code-excited linear prediction(ACELP) coding technique while the last two layers are coded using the transform coded ...