title: Wrapping an existing RTP stream with RTSP
body: <p>I have a RTP multicast stream from ffmpeg that requires users to use external SDP files, as this sometimes becomes a problem I was thinking of wrapping the stream using RTSP.</p>
  
  <p>I have an application that already makes some management for the RTP stream, so it would be useful to have the RTSP wrapper inside it as well, although I don't want the wrapper to do anything beyond delivering the SDP information. Right now I'd say I'm correctly delivering the SDP information (otherwise it's stuck in that request), however I'm not getting any PLAY command, the player is stuck after the SETUP request, so I guess my reply is wrong, but after testing many different values for the Transport header I haven't been able to get anything beyond this point.</p>
  
  <p>This is the SDP:</p>
  
  <p><code>v=0
   o=- 0 0 IN IP4 127.0.0.1
   s=No Name
   c=IN IP4 236.0.0.1
   t=0 0
   a=tool:libavformat 56.7.102
   m=video 2000 RTP/AVP 96
   b=AS:500
   a=rtpmap:96 H264/90000
   a=fmtp:96 packetization-mode=1</code></p>
  
  <p>This is a sample SETUP request from VLC:</p>
  
  <p><code>SETUP rtsp://127.0.0.1:34343/live.sdp/ RTSP/1.0
  CSeq: 4
  User-Agent: LibVLC/2.1.5 (LIVE555 Streaming Media v2014.05.27)
  Transport: RTP/AVP;multicast;client_port=2000-2001</code></p>
  
  <p>And one of many replies I've tried:</p>
  
  <p><code>RTSP/1.0 200 OK
  CSeq: 4
  Transport: RTP/AVP;multicast;client_port=2000-2001;source=236.0.0.1;port=2000-2001
  Session: 0456804596</code></p>
  
  <p>I've tried using destination instead of source, server_port instead of port, also, although the RTP multicast port is 2000, I've seen the streaming is also using other ports like 57927 and 57928, so I've tried those ones as well, etc.</p>