webrtc基础音频信号处理，以及CNG模块提取，并向其中附加了G7221C编解码器，用于处理7221音频数据和VAD活动语音检测后的CNG包，用于服务器处理流媒体数据，混音等的操作。-webrtc base audio signal processing, as well as CNG module extracts, to which is added G7221C codec 7221 for processing audio data and voice activity detecti