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229 lines
8.1 KiB
C#
229 lines
8.1 KiB
C#
// Authors
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// Copyright (C) 2014 Stephan Sundermann <stephansundermann@gmail.com>
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using System;
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using Gst;
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using System.Runtime.InteropServices;
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namespace GstreamerSharp
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{
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class Playback
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{
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const int ChunkSize = 1024;
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const int SampleRate = 44100;
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static Gst.App.AppSink AppSink;
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static Gst.App.AppSrc AppSource;
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static Element Pipeline, Tee, AudioQueue, AudioConvert1, AudioResample, AudioSink;
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static Element VideoQueue, AudioConvert2, Visual, VideoConvert, VideoSink;
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static Element AppQueue;
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static long NumSamples; // Number of samples generated so far (for timestamp generation)
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static float a, b, c, d; // For waveform generation
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static uint Sourceid; // To control the GSource
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static GLib.MainLoop MainLoop; // GLib's Main Loop
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// This method is called by the idle GSource in the mainloop, to feed CHUNK_SIZE bytes into appsrc.
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// The idle handler is added to the mainloop when appsrc requests us to start sending data (need-data signal)
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// and is removed when appsrc has enough data (enough-data signal).
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static bool PushData () {
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var numSamples = ChunkSize / 2; // Because each sample is 16 bits
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MapInfo map;
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// Create a new empty buffer
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var buffer = new Gst.Buffer (null, ChunkSize, AllocationParams.Zero);
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// Set its timestamp and duration
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buffer.Pts = Util.Uint64Scale ((ulong)NumSamples, (ulong)Constants.SECOND, (ulong)SampleRate);
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buffer.Dts = Util.Uint64Scale ((ulong)NumSamples, (ulong)Constants.SECOND, (ulong)SampleRate);
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buffer.Duration = Util.Uint64Scale ((ulong)NumSamples, (ulong)Constants.SECOND, (ulong)SampleRate);
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// Generate some psychodelic waveforms
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buffer.Map (out map, MapFlags.Write);
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c += d;
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d -= c / 1000f;
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var freq = 1100f + 1000f * d;
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short[] data = new short[numSamples];
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for (int i = 0; i < numSamples; i++) {
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a += b;
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b -= a / freq;
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data[i] = (short)(500f * a);
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}
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// convert the short[] to a byte[] by marshalling
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var native = Marshal.AllocHGlobal (data.Length * sizeof(short));
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Marshal.Copy (data, 0, native, data.Length);
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byte[] bytedata = new byte[2 * data.Length];
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Marshal.Copy (native, bytedata, 0, data.Length * sizeof(short));
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map.Data = bytedata;
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buffer.Unmap (map);
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NumSamples += numSamples;
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// Push the buffer into the appsrc
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var ret = AppSource.PushBuffer (buffer);
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// Free the buffer now that we are done with it
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buffer.Dispose ();
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if (ret != FlowReturn.Ok) {
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// We got some error, stop sending data
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return false;
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}
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return true;
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}
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// This signal callback triggers when appsrc needs Here, we add an idle handler
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// to the mainloop to start pushing data into the appsrc
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static void StartFeed (object sender, Gst.App.NeedDataArgs args) {
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if (Sourceid == 0) {
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Console.WriteLine ("Start feeding");
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Sourceid = GLib.Idle.Add (PushData);
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}
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}
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// This callback triggers when appsrc has enough data and we can stop sending.
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// We remove the idle handler from the mainloop
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static void StopFeed (object sender, EventArgs args) {
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if (Sourceid != 0) {
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Console.WriteLine ("Stop feeding");
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GLib.Source.Remove (Sourceid);
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Sourceid = 0;
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}
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}
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// The appsink has received a buffer
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static void NewSample (object sender, GLib.SignalArgs args) {
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var sink = (Gst.App.AppSink)sender;
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// Retrieve the buffer
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var sample = sink.PullSample ();
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if (sample != null) {
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// The only thing we do in this example is print a * to indicate a received buffer
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Console.Write ("*");
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sample.Dispose ();
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}
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}
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// This function is called when an error message is posted on the bus
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static void HandleError (object sender, GLib.SignalArgs args) {
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GLib.GException err;
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string debug;
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var msg = (Message) args.Args[0];
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// Print error details on the screen
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msg.ParseError (out err, out debug);
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Console.WriteLine ("Error received from element {0}: {1}", msg.Src.Name, err.Message);
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Console.WriteLine ("Debugging information: {0}", debug != null ? debug : "none");
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MainLoop.Quit ();
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}
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public static void Main (string[] args)
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{
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b = 1;
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d = 1;
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Gst.Audio.AudioInfo info = new Gst.Audio.AudioInfo();
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// Initialize Gstreamer
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Gst.Application.Init(ref args);
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// Create the elements
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AppSource = new Gst.App.AppSrc ("app_src");
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Tee = ElementFactory.Make ("tee", "tee");
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AudioQueue = ElementFactory.Make ("queue", "audio_queue");
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AudioConvert1 = ElementFactory.Make ("audioconvert", "audio_convert1");
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AudioResample = ElementFactory.Make ("audioresample", "audio_resample");
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AudioSink = ElementFactory.Make ("autoaudiosink", "audio_sink");
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VideoQueue = ElementFactory.Make ("queue", "video_queue");
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AudioConvert2 = ElementFactory.Make ("audioconvert", "audio_convert2");
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Visual = ElementFactory.Make ("wavescope", "visual");
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VideoConvert = ElementFactory.Make ("videoconvert", "video_convert");
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VideoSink = ElementFactory.Make ("autovideosink", "video_sink");
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AppQueue = ElementFactory.Make ("queue", "app_queue");
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AppSink = new Gst.App.AppSink ("app_sink");
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// Create the empty pipeline
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var pipeline = new Pipeline ("test-pipeline");
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if (AppSource == null || Tee == null || AudioQueue == null || AudioConvert1 == null || AudioResample == null ||
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AudioSink == null || VideoQueue == null || AudioConvert2 == null || Visual == null || VideoConvert == null ||
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AppQueue == null || AppSink == null ||pipeline == null) {
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Console.WriteLine ("Not all elements could be created.");
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return;
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}
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// Configure wavescope
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Visual ["shader"] = 0;
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Visual ["style"] = 0;
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// Configure appsrc
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Gst.Audio.AudioChannelPosition[] position = {};
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info.SetFormat (Gst.Audio.AudioFormat.S16, SampleRate, 1, position);
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var audioCaps = info.ToCaps ();
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AppSource ["caps"] = audioCaps;
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AppSource ["format"] = Format.Time;
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AppSource.NeedData += StartFeed;
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AppSource.EnoughData += StopFeed;
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// Configure appsink
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AppSink ["emit-signals"] = true;
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AppSink ["caps"] = audioCaps;
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AppSink.NewSample += NewSample;
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// Link all elements that can be automatically linked because they have "Always" pads
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pipeline.Add (AppSource, Tee, AudioQueue, AudioConvert1, AudioResample,
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AudioSink, VideoQueue, AudioConvert2, Visual, VideoConvert, VideoSink, AppQueue, AppSink);
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if (!Element.Link (AppSource, Tee) ||
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!Element.Link (AudioQueue, AudioConvert1, AudioResample, AudioSink) ||
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!Element.Link (VideoQueue, AudioConvert2, Visual, VideoConvert, VideoSink) ||
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!Element.Link (AppQueue, AppSink)) {
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Console.WriteLine ("Elements could not be linked.");
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return;
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}
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// Manually link the Tee, which has "Request" pads
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var teeSrcPadTemplate = Tee.GetPadTemplate ("src_%u");
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var teeAudioPad = Tee.RequestPad (teeSrcPadTemplate);
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Console.WriteLine ("Obtained request pad {0} for audio branch.", teeAudioPad.Name);
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var queueAudioPad = AudioQueue.GetStaticPad ("sink");
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var teeVideoPad = Tee.RequestPad (teeSrcPadTemplate);
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Console.WriteLine ("Obtained request pad {0} for video branch.", teeVideoPad.Name);
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var queueVideoPad = VideoQueue.GetStaticPad ("sink");
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var teeAppPad = Tee.RequestPad (teeSrcPadTemplate);
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Console.WriteLine ("Obtained request pad {0} for app branch.", teeAppPad.Name);
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var queueAppPad = AppQueue.GetStaticPad ("sink");
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if (teeAudioPad.Link (queueAudioPad) != PadLinkReturn.Ok ||
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teeVideoPad.Link (queueVideoPad) != PadLinkReturn.Ok ||
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teeAppPad.Link (queueAppPad) != PadLinkReturn.Ok) {
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Console.WriteLine ("Tee could not be linked");
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return;
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}
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// Instruct the bus to emit signals for each received message, and connect to the interesting signals
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var bus = pipeline.Bus;
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bus.AddSignalWatch ();
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bus.Connect ("message::error", HandleError);
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// Start playing the pipeline
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pipeline.SetState (State.Playing);
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// Create a GLib Main Loop and set it to run
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MainLoop = new GLib.MainLoop ();
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MainLoop.Run ();
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// Release the request pads from the Tee, and unref them
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Tee.ReleaseRequestPad(teeAudioPad);
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Tee.ReleaseRequestPad(teeVideoPad);
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Tee.ReleaseRequestPad(teeAppPad);
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// Free resources
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pipeline.SetState (State.Null);
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Gst.Global.Deinit();
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}
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}
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}
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