低比特率语声编码器的新发展

New Development of Low BitRate Speech Coders

ＩＴＵ－Ｔ建议Ｒｅｃ．Ｇ．７２９、Ｒｅｃ．Ｇ．７２９ＡｎｎｅｘＡ和Ｒｅｃ．Ｇ．７２３．１是国际电信联盟（ＩＴＵ）最新颁布的三种适用于多媒体通信的低比特率线性预测语声编码器标准．本文介绍了语声编码器的比特率、复杂度、延迟和音质等性能指标的含义，并通过比较这三种新型声码器在算法和性能指标上的异同点，讨论它们在多媒体通信中的不同应用．

Newly issued by the International Telecommunications Union (ITU) G.729,G.729Annex A and G.723.1 are three standards of low bitrate linearprediction speech coders, applicable to multimedia communications. This paper introduces the implications of speech coders performance indices such as bitrate, complexity, delay, quality and so on. It also discusses the different application of these three coders by comparing their similarity and differences in both algorithm and performance.