Speex是一套主要针对语音的开源免费，无专利保护的应用集合，它不仅包括编解码器，还包括VAD(语音检测),DTX(不连续传输),AEC(回声消除),NS(去噪)等实用模块。(Speex is a set of open source free, patent free application set, which is mainly for voice. It not only includes codec, but also includes VAD (voice detection), D