一个用c写的基于sip协议栈的demo用户端程序，简单易懂，对sip的VoIP的学习有借鉴作用。-A demo client program based on sip protocol stack, which is easy to understand, and helpful to learn VoIP based on sip.

SIP协议栈命令使用，接收相机数据并解码播放。-The demo use the SIP protocol, recieving camera data and decoder it,then display it.