从相机previewcallback得来的预览数据流，采用H264编码，存储到本的SD卡，H264编码器采用x264移植到Android的动态库，对于andriod视频处理具有较大参考价值-get data stream from the camera previewcallback, using the H264 encoder, and then store in this SD card, the H264 encoder using x264 ported to the Android