sample: Add basic tutorial 8 sample

samples/BasicTutorial8.cs

@@ -0,0 +1,226 @@
+// Authors
+//   Copyright (C) 2014 Stephan Sundermann <stephansundermann@gmail.com>
+
+using System;
+using Gst;
+using System.Runtime.InteropServices;
+
+namespace GstreamerSharp
+{
+	class Playback
+	{
+		const int ChunkSize = 1024;
+		const int SampleRate = 44100;
+
+		static Gst.App.AppSink AppSink;
+		static Gst.App.AppSrc AppSource;
+		static Element Pipeline, Tee, AudioQueue, AudioConvert1, AudioResample, AudioSink;
+		static Element VideoQueue, AudioConvert2, Visual, VideoConvert, VideoSink;
+		static Element AppQueue;
+
+		static long NumSamples;   // Number of samples generated so far (for timestamp generation)
+		static float a, b, c, d;     // For waveform generation
+
+		static uint Sourceid;        // To control the GSource
+
+		static GLib.MainLoop MainLoop;  // GLib's Main Loop
+
+		// This method is called by the idle GSource in the mainloop, to feed CHUNK_SIZE bytes into appsrc.
+		// The idle handler is added to the mainloop when appsrc requests us to start sending data (need-data signal)
+		// and is removed when appsrc has enough data (enough-data signal).
+
+		static bool PushData () {
+			var numSamples = ChunkSize / 2; // Because each sample is 16 bits
+			MapInfo map;
+
+			// Create a new empty buffer
+			var buffer = new Gst.Buffer (null, ChunkSize, AllocationParams.Zero);
+
+			// Set its timestamp and duration
+			buffer.Pts = Util.Uint64Scale ((ulong)NumSamples, (ulong)Constants.SECOND, (ulong)SampleRate);
+			buffer.Dts = Util.Uint64Scale ((ulong)NumSamples, (ulong)Constants.SECOND, (ulong)SampleRate);
+			buffer.Duration = Util.Uint64Scale ((ulong)NumSamples, (ulong)Constants.SECOND, (ulong)SampleRate);
+
+			// Generate some psychodelic waveforms
+			buffer.Map (out map, MapFlags.Write);
+			c += d;
+			d -= c / 1000f;
+			var freq = 1100f + 1000f * d;
+			short[] data = new short[numSamples];
+			for (int i = 0; i < numSamples; i++) {
+				a += b;
+				b -= a / freq;
+				data[i] = (short)(500f * a);
+			}
+			// convert the short[] to a byte[] by marshalling
+			var native = Marshal.AllocHGlobal (data.Length * sizeof(short));
+			Marshal.Copy (data, 0, native, data.Length);
+			byte[] bytedata = new byte[2 * data.Length];
+			Marshal.Copy (native, bytedata, 0, data.Length * sizeof(short));
+
+			map.Data = bytedata;
+			buffer.Unmap (map);
+			NumSamples += numSamples;
+
+			// Push the buffer into the appsrc
+			var ret = AppSource.PushBuffer (buffer);
+
+			// Free the buffer now that we are done with it
+			buffer.Dispose ();
+
+			if (ret != FlowReturn.Ok) {
+				// We got some error, stop sending data
+				return false;
+			}
+			return true;
+		}
+
+		// This signal callback triggers when appsrc needs  Here, we add an idle handler
+		// to the mainloop to start pushing data into the appsrc
+		static void StartFeed (object sender, Gst.App.NeedDataArgs args) {
+			if (Sourceid == 0) {
+				Console.WriteLine ("Start feeding");
+				Sourceid = GLib.Idle.Add (PushData);
+			}
+		}
+
+		// This callback triggers when appsrc has enough data and we can stop sending.
+		// We remove the idle handler from the mainloop
+		static void StopFeed (object sender, EventArgs args) {
+			if (Sourceid != 0) {
+				Console.WriteLine ("Stop feeding");
+				GLib.Source.Remove (Sourceid);
+				Sourceid = 0;
+			}
+		}
+
+		// The appsink has received a buffer
+		static void NewSample (object sender, GLib.SignalArgs args) {
+			var sink = (Gst.App.AppSink)sender;
+
+			// Retrieve the buffer
+			var sample = sink.PullSample ();
+			if (sample != null) {
+				// The only thing we do in this example is print a * to indicate a received buffer
+				Console.Write ("*");
+				sample.Dispose ();
+			}
+		}
+
+		// This function is called when an error message is posted on the bus
+		static void HandleError (object sender, GLib.SignalArgs args) {
+			GLib.GException err;
+			string debug;
+			var msg = (Message) args.Args[0];
+
+			// Print error details on the screen
+			msg.ParseError (out err, out debug);
+			Console.WriteLine ("Error received from element {0}: {1}", msg.Src.Name, err.Message);
+			Console.WriteLine ("Debugging information: {0}", debug != null ? debug : "none");
+
+			MainLoop.Quit ();
+		}
+
+		public static void Main (string[] args)
+		{
+			b = 1;
+			d = 1;
+			Gst.Audio.AudioInfo info = Gst.Audio.AudioInfo.Zero;
+
+			// Initialize Gstreamer
+			Gst.Application.Init(ref args);
+
+			// Create the elements
+			AppSource = new Gst.App.AppSrc ("app_src");
+			Tee = ElementFactory.Make ("tee", "tee");
+			AudioQueue = ElementFactory.Make ("queue", "audio_queue");
+			AudioConvert1 = ElementFactory.Make ("audioconvert", "audio_convert1");
+			AudioResample = ElementFactory.Make ("audioresample", "audio_resample");
+			AudioSink = ElementFactory.Make ("autoaudiosink", "audio_sink");
+			VideoQueue = ElementFactory.Make ("queue", "video_queue");
+			AudioConvert2 = ElementFactory.Make ("audioconvert", "audio_convert2");
+			Visual = ElementFactory.Make ("wavescope", "visual");
+			VideoConvert = ElementFactory.Make ("videoconvert", "video_convert");
+			VideoSink = ElementFactory.Make ("autovideosink", "video_sink");
+			AppQueue = ElementFactory.Make ("queue", "app_queue");
+			AppSink = new Gst.App.AppSink ("app_sink");
+
+			// Create the empty pipeline
+			var pipeline = new Pipeline ("test-pipeline");
+
+			if (AppSource == null || Tee == null || AudioQueue == null || AudioConvert1 == null || AudioResample == null || 
+				AudioSink == null || VideoQueue == null || AudioConvert2 == null || Visual == null || VideoConvert == null || 
+				AppQueue == null || AppSink == null ||pipeline == null) {
+				Console.WriteLine ("Not all elements could be created.");
+				return;
+			}
+
+			// Configure wavescope
+			Visual ["shader"] = 0;
+			Visual ["style"] = 0;
+
+			// Configure appsrc
+			info.SetFormat (Gst.Audio.AudioFormat.S16, SampleRate, 1, (Gst.Audio.AudioChannelPosition) 0);
+			var audioCaps = info.ToCaps ();
+			AppSource ["caps"] = audioCaps;
+			AppSource ["format"] = Format.Time;
+
+			AppSource.NeedData += StartFeed;
+			AppSource.EnoughData += StopFeed;
+
+			// Configure appsink
+			AppSink ["emit-signals"] = true;
+			AppSink ["caps"] = audioCaps;
+			AppSink.NewSample += NewSample;
+
+			// Link all elements that can be automatically linked because they have "Always" pads
+			pipeline.Add (AppSource, Tee, AudioQueue, AudioConvert1, AudioResample, 
+				AudioSink, VideoQueue, AudioConvert2, Visual, VideoConvert, VideoSink, AppQueue, AppSink);
+			if (!Element.Link (AppSource, Tee) ||
+				!Element.Link (AudioQueue, AudioConvert1, AudioResample, AudioSink) ||
+				!Element.Link (VideoQueue, AudioConvert2, Visual, VideoConvert, VideoSink) ||
+				!Element.Link (AppQueue, AppSink)) {
+				Console.WriteLine ("Elements could not be linked.");
+				return;
+			}
+
+			// Manually link the Tee, which has "Request" pads
+			var teeSrcPadTemplate = Tee.GetPadTemplate ("src_%u");
+			var teeAudioPad = Tee.RequestPad (teeSrcPadTemplate);
+			Console.WriteLine ("Obtained request pad {0} for audio branch.", teeAudioPad.Name);
+			var queueAudioPad = AudioQueue.GetStaticPad ("sink");
+			var teeVideoPad = Tee.RequestPad (teeSrcPadTemplate);
+			Console.WriteLine ("Obtained request pad {0} for video branch.", teeVideoPad.Name);
+			var queueVideoPad = VideoQueue.GetStaticPad ("sink");
+			var teeAppPad = Tee.RequestPad (teeSrcPadTemplate);
+			Console.WriteLine ("Obtained request pad {0} for app branch.", teeAppPad.Name);
+			var queueAppPad = AppQueue.GetStaticPad ("sink");
+			if (teeAudioPad.Link (queueAudioPad) != PadLinkReturn.Ok ||
+				teeVideoPad.Link (queueVideoPad) != PadLinkReturn.Ok ||
+				teeAppPad.Link (queueAppPad) != PadLinkReturn.Ok) {
+				Console.WriteLine ("Tee could not be linked");
+				return;
+			}
+
+			// Instruct the bus to emit signals for each received message, and connect to the interesting signals
+			var bus = pipeline.Bus;
+			bus.AddSignalWatch ();
+			bus.Connect ("message::error", HandleError);
+
+			// Start playing the pipeline
+			pipeline.SetState (State.Playing);
+
+			// Create a GLib Main Loop and set it to run
+			MainLoop = new GLib.MainLoop ();
+			MainLoop.Run ();
+
+			// Release the request pads from the Tee, and unref them
+			Tee.ReleaseRequestPad(teeAudioPad);
+			Tee.ReleaseRequestPad(teeVideoPad);
+			Tee.ReleaseRequestPad(teeAppPad);
+
+			// Free resources
+			pipeline.SetState (State.Playing);
+		}
+	}
+}

samples/Makefile.am

@@ -1,4 +1,4 @@
-TARGETS = playback.exe video-overlay.exe basic-tutorial-1.exe basic-tutorial-2.exe basic-tutorial-3.exe basic-tutorial-4.exe basic-tutorial-5.exe basic-tutorial-6.exe basic-tutorial-7.exe
+TARGETS = playback.exe video-overlay.exe basic-tutorial-1.exe basic-tutorial-2.exe basic-tutorial-3.exe basic-tutorial-4.exe basic-tutorial-5.exe basic-tutorial-6.exe basic-tutorial-7.exe basic-tutorial-8.exe
 
 DEBUGS = $(addsuffix .mdb, $(TARGETS))
 assemblies = 					\
@@ -36,6 +36,9 @@ basic-tutorial-6.exe: $(srcdir)/BasicTutorial6.cs $(assemblies)
 basic-tutorial-7.exe: $(srcdir)/BasicTutorial7.cs $(assemblies)
 	$(CSC) $(CSFLAGS) -out:basic-tutorial-7.exe $(references) $(GLIB_SHARP_LIBS) $(srcdir)/BasicTutorial7.cs
 
+basic-tutorial-8.exe: $(srcdir)/BasicTutorial8.cs $(assemblies)
+	$(CSC) $(CSFLAGS) -out:basic-tutorial-8.exe $(references) $(GLIB_SHARP_LIBS) $(srcdir)/BasicTutorial8.cs
+
 EXTRA_DIST = 				\
 	Playback.cs \
     VideoOverlay.cs \
@@ -45,4 +48,5 @@ EXTRA_DIST = 				\
     BasicTutorial4.cs \
     BasicTutorial5.cs \
     BasicTutorial6.cs \
-    BasicTutorial7.cs
+    BasicTutorial7.cs \
+    BasicTutorial8.cs