宽带语音编码技术专题讲座(一) 第2讲 宽带嵌入式可变速率语音和音频编解码器:ITU-T G.718  

A Wideband Embedded Variable Bit-rate Speech and Audio Codec:ITU-T G.718

作　　者：郑国宏[1] 陈亮[1] 王金明[1] 尹廷辉[1] 

机构地区：[1]解放军理工大学通信工程学院电子信息系,江苏南京210007

出　　处：《军事通信技术》2011年第2期92-96,共5页Journal of Military Communications Technology

摘　　要：文章介绍了一种嵌入式可变速率宽带语音和音频编解码器ITU-T G.718。G.718编解码器能在8 kbit/s^32 kbit/s的可变速率上对16 kHz采样的语音和音频信号进行编解码。G.718编解码器具有5层结构,当高一层的码流被丢弃时不会影响到低一层码流的解码。核心层编码采用基于信号分类的CELP编码,L2层通过增加基音的贡献以及增加代数码本的方式对核心层的编码误差进行编码,L3、L4、L5层编码时,每个编码层对低一层编码的加权误差信号采用MDCT变换编码。测试了G.718编码器的WB-PESQ得分情况,结果表明,在相同速率下,G.718算法的性能优于G.729.1。The principle of embedded variable bit-rate wideband codec ITU-T G. 718 is intro- duced. The codec provides a scalable solution for compression of 16 kHz sampled speech and au- dio signals at rates between 8 kbit/s and 32 kbit/s. It comprises 5 layers where higher layer bitstreams can be discarded without affecting the lower layer decoding. The core layer takes advantage of signal-classification based CELP encoding. The second layer reduces the coding error from the first layer by additional pitch contribution and another algebraic codebook. The higher layers encode the weighted error signal from lower layers using MDCT transform coding. WB-PESQ scores of G. 718 and G. 729. 1 are tested, and the results show that the quality of G. 718 is better than G. 729.1 at the same rates.

关 键 词：语音编码 宽带语音编码 嵌入式语音编码 

分 类 号：TN912.3[电子电信—通信与信息系统]