title: SDP message construction?
body: <p>I was wondering can anyone point me to a good tutorial on how to construct a SDP message.</p>
  
  <p>I have read the basics and can construct and understand the parameters but I just can't seem to get it to work.</p>
  
  <p>I either get a not acceptable here reply or no reply at all, this is after I get 100 Trying and 180 ringing back.</p>
  
  <p>So my SIP works but it doesn't like the SDP Data.</p>
  
  <p>Its currently constructed like this:</p>
  
  <pre><code>String sdpData = "v=0\r\n"
              + "o=- 019078020 0"
              + " IN IP4  sip.ciceronetworks.com\r\n" + "s=MySession\r\n"
              + "c=IN IP4  sip.ciceronetworks.com\r\n"
              + "t=0 0\r\n" + "m=audio 6002 RTP/AVP 0\r\n"
              + "a=sendrecv\r\n" + "a=rtpmap:0 PCMU/8000\r\n" + "a=ptime:20\r\n"+ "a=fmtp:97 mode=20\r\n";
  
  
      byte[] contents = sdpData.getBytes(); 
  
      request.setContent(contents, contentTypeHeader); 
  </code></pre>
  
  <p>And while like that I get 100 trying then 180 ringing but when I accept the call on the other end I get nothing back at all, it seems to just crash, I also get "Audio device Error" on the pc client that I try ringing.</p>
  
  <p>Anyone any ideas?</p>