RTSP_Presentation.md

+# RTSP.Presentation
+
+## Constructor arguments
+
+A single `System.Uri` with the Url of the presentation.
+
+## Usage
+
+Start by requesting the Session Description by calling
+`GetSessionDescriptionAsync()`. It will return a `Task<SessionDescription>`.
+This task will be completed when the `SessionDescription` is available.
+
+Using the `SessionDescription` each media format (audio, video or other) that is
+available can be examined. Each media format that is to be streamed can be set
+up with a call to `SetupAsync()`. Each call will return a `Task<Session>` that
+will be completed when the media stream has been set up. The task result
+`Session` object is the source of the RTP packets that will be streamed for the
+selected media format.
+
+`Session`is an `IObservable<Packet>`source and the sink that is to consume the
+RTP packets has to implement the `IObserver<Packet>` interface.
+
+When all required sinks are set up streaming is started by calling
+`PlayAsync()`. The task returned will be completed when a response has been
+received to the RTSP PLAY request.
+
+To stop all the streams call `StopAsync()`. The task returned will be completed
+when a response has been received to the RTSP TEARDOWN request.
+
+## Code example
+
+An example to stream the video media only and checking if format/codec is
+supported:
+
+```c#
+Uri url = new Uri("rtsp://server/presentation", UriKind.Absolute);
+Presentation p = new Presentation(url);
+SessionDescription sdp = await p.GetSessionDescriptionAsync();
+
+//  Process video media only.
+Media media = sdp.MediaDescriptions
+    .Where(m => { return m.MediaType == SessionDescription.MediaType.video; })
+    .First();
+
+//  Is this video codec supported?
+IObserver<Packet> mediaSink = CreateVideoSink(media);
+if (mediaSink != null)
+{
+    Session s = await p.SetupAsync(media);
+    s.Subscribe(mediaSink);
+
+    //  Start playing the video.
+    await p.PlayAsync();
+}
+```
+
+Stop the presentation started above.
+
+```c#
+await p.StopAsync();
+```