F Added SDP mungling

Author: jimm98y

src/RTSPServerFFmpeg/Program.cs

@@ -14,43 +14,24 @@
     server.AddVideoTrack(new ProxyTrack(0, "rtp://127.0.0.1:11111"));
     server.AddAudioTrack(new ProxyTrack(1, "rtp://127.0.0.1:11113"));
     // original
-    //string sdp =
-    //    "v=0\r\n" +
-    //    "o=- 0 0 IN IP4 127.0.0.1\r\n" +
-    //    "s=No Name\r\n" +
-    //    "t=0 0\r\n" +
-    //    "a=tool:libavformat 60.3.100\r\n" +
-    //    "m=video 11111 RTP/AVP 96\r\n" +
-    //    "c=IN IP4 127.0.0.1\r\n" +
-    //    "b=AS:587\r\n" +
-    //    "a=rtpmap:96 H264/90000\r\n" +
-    //    "a=fmtp:96 packetization-mode=1; sprop-parameter-sets=Z2QAHqzZQKAv+WagwCDW4AAAAwAgAAAGAeLFssA=,aOvjyyLA; profile-level-id=64001E\r\n" +
-    //    "m=audio 11113 RTP/AVP 97\r\n" +
-    //    "c=IN IP4 127.0.0.1\r\n" +
-    //    "b=AS:69\r\n" +
-    //    "a=rtpmap:97 MPEG4-GENERIC/44100/1\r\n" +
-    //    "a=fmtp:97 profile-level-id=1;mode=AAC-hbr;sizelength=13;indexlength=3;indexdeltalength=3; config=120856E500\r\n\r\n";
-
     string sdp =
         "v=0\r\n" +
         "o=- 0 0 IN IP4 127.0.0.1\r\n" +
         "s=No Name\r\n" +
         "t=0 0\r\n" +
         "a=tool:libavformat 60.3.100\r\n" +
         "m=video 11111 RTP/AVP 96\r\n" +
-        "a=control:trackID=0\n" + // TODO: add this
         "c=IN IP4 127.0.0.1\r\n" +
         "b=AS:587\r\n" +
         "a=rtpmap:96 H264/90000\r\n" +
         "a=fmtp:96 packetization-mode=1; sprop-parameter-sets=Z2QAHqzZQKAv+WagwCDW4AAAAwAgAAAGAeLFssA=,aOvjyyLA; profile-level-id=64001E\r\n" +
         "m=audio 11113 RTP/AVP 97\r\n" +
-        "a=control:trackID=1\n" + // TODO: add this
         "c=IN IP4 127.0.0.1\r\n" +
         "b=AS:69\r\n" +
         "a=rtpmap:97 MPEG4-GENERIC/44100/1\r\n" +
-        "a=fmtp:97 profile-level-id=1;mode=AAC-hbr;sizelength=13;indexlength=3;indexdeltalength=3; config=120856E500\r\n\r\n";
+        "a=fmtp:97 profile-level-id=1;mode=AAC-hbr;sizelength=13;indexlength=3;indexdeltalength=3; config=120856E500\r\n\r\n";    
 
-    server.OverrideSDP(sdp);
+    server.OverrideSDP(sdp, true);
 
     try
     {

src/SharpRTSPServer/RTSPServer.cs

@@ -1,11 +1,13 @@
 using Microsoft.Extensions.Logging;
 using Rtsp;
 using Rtsp.Messages;
+using Rtsp.Sdp;
 using System;
 using System.Buffers;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Diagnostics.Contracts;
+using System.IO;
 using System.Linq;
 using System.Net;
 using System.Net.Sockets;
@@ -746,8 +748,38 @@ protected virtual void Dispose(bool disposing)
             }
         }
 
-        public void OverrideSDP(string sdp)
+        public void OverrideSDP(string sdp, bool mungleSDP = true)
         {
+            if (mungleSDP)
+            {
+                if (!sdp.Contains("a=control:"))
+                {
+                    StringBuilder builder = new StringBuilder();
+                    int mediaIndex = 0;
+
+                    // we have to fill in the trackID to identify the session in RTSP
+                    using (var textReader = new StringReader(sdp))
+                    {
+                        while(true)
+                        {
+                            string line = textReader.ReadLine();
+
+                            if (line == null)
+                                break;
+
+                            builder.AppendLine(line);
+
+                            if(line.StartsWith("m="))
+                            {
+                                builder.AppendLine($"a=control:trackID={mediaIndex++}");
+                            }
+                        }
+                    }
+
+                    sdp = builder.ToString();
+                }
+            }
+
             this._sdp = sdp;
         }