libavformat/rtsp.c:1998: error: Uninitialized Value
  The value read from payload_type was never initialized.

libavformat/rtsp.c:1998:9: 
1996. 
1997.     if (ff_rtp_get_codec_info(&codec, payload_type)) {
1998.         av_log(s, AV_LOG_ERROR, "Unable to receive RTP payload type %d "
              ^
1999.                                 "without an SDP file describing it\n",
2000.                                  payload_type);
