transport

pFormatCtx = avformat_alloc_context();
//有三种传输方式：tcp udp_multicast udp，强制采用tcp传输
AVDictionary* options = NULL;
av_dict_set(&options, "rtsp_transport", "tcp", 0);
if(avformat_open_input(&pFormatCtx, [moviePath cStringUsingEncoding:NSASCIIStringEncoding], NULL, &options) != 0) {
av_log(NULL, AV_LOG_ERROR, "Couldn't open file\n");
goto initError;
}
// Retrieve stream information
if(avformat_find_stream_info(pFormatCtx,NULL) < 0) {
av_log(NULL, AV_LOG_ERROR, "Couldn't find stream information\n");
goto initError;
}