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c#winformsvideo-streaminggstreamergstreamer-sharp

Display gstreamer-sharp video stream in WinForms


I am looking for an example/help for displaying a gstreamer-sharp feed in a WinForms application.

I am using VS 2012 and have the "glue" project built for this version of VS. I also have glib-sharp, gstreamer-sharp installed and referenced by my project. I have the gstreamer bin directory set as my project's working directory.

If have the following code in a button click handler I get the GStreamer D3D video sink test Window which pops-up on top of my Form.

Gst.Application.Init();
var pipeline = Parse.Launch(@"videotestsrc ! videoconvert ! autovideosink");
pipeline.SetState(State.Playing);

I would like to get the stream displaying within my application on a Panel or PictureBox I'm thinking.

Thanks!


Solution

  • The code below will get the test stream to display on a WinForm's panel control.

    internal enum videosinktype { glimagesink, d3dvideosink, dshowvideosink, directdrawsink}
    
    static Element mVideoTestSource, mVideoCaps, mVideoSink, mAppQueue, mVideoConv;
    static Gst.App.AppSink mAppSink;
    static System.Threading.Thread mMainGlibThread;
    static GLib.MainLoop mMainLoop;  // GLib's Main Loop
    
    private const videosinktype mCfgVideosinkType = videosinktype.dshowvideosink;
    private ulong mHandle;
    private Gst.Video.VideoSink mGlImageSink;
    private Gst.Pipeline mCurrentPipeline = null;
    
    private void InitGStreamerPipeline()
    {
        //Assign Handle to prevent Cross-Threading Access
        mHandle = (ulong)videoDisplay.Handle;
    
        //Init Gstreamer
        Gst.Application.Init();    
        GtkSharp.GstreamerSharp.ObjectManager.Initialize();
    
        mMainLoop = new GLib.MainLoop();
        mMainGlibThread = new System.Threading.Thread(mMainLoop.Run);
        mMainGlibThread.Start();
    
        #region BuildPipeline   
        switch (mCfgVideosinkType)
        {
            case videosinktype.glimagesink:
                mGlImageSink = (Gst.Video.VideoSink)Gst.ElementFactory.Make("glimagesink", "glimagesink");
                break;
            case videosinktype.d3dvideosink:
                mGlImageSink = (Gst.Video.VideoSink)Gst.ElementFactory.Make("d3dvideosink", "d3dvideosink");
                //mGlImageSink = (Gst.Video.VideoSink)Gst.ElementFactory.Make("dshowvideosink", "dshowvideosink");
                break;  
            case videosinktype.dshowvideosink:
                mGlImageSink = (Gst.Video.VideoSink)Gst.ElementFactory.Make("dshowvideosink", "dshowvideosink");
                break;
            case videosinktype.directdrawsink:
                mGlImageSink = (Gst.Video.VideoSink)Gst.ElementFactory.Make("directdrawsink", "directdrawsink");
                break;
            default:
                break;
        }
    
        mVideoTestSource = ElementFactory.Make("videotestsrc", "videotestsrc0");
        mVideoConv = ElementFactory.Make("videoconvert", "vidconvert0");
        mVideoSink = ElementFactory.Make("autovideosink", "sink0");
    
        mCurrentPipeline = new Gst.Pipeline("pipeline");    
        mCurrentPipeline.Add(mVideoTestSource, mVideoConv, mVideoSink, mGlImageSink);
    
        if (!mVideoTestSource.Link(mVideoSink))
        if (mUdpcSrc.Link(mVideoSink))            
        {
            System.Diagnostics.Debug.WriteLine("Elements could not be linked");
        }
        #endregion
    
        //subscribe to bus & bussync msgs
        Bus bus = mCurrentPipeline.Bus;
        bus.AddSignalWatch();
        bus.Message += HandleMessage;
    
        Bus bus = mCurrentPipeline.Bus;
        bus.EnableSyncMessageEmission();
        bus.SyncMessage += new SyncMessageHandler(bus_SyncMessage);
    
        //play the stream
        var setStateRet = mCurrentPipeline.SetState(State.Null);
        System.Diagnostics.Debug.WriteLine("SetStateNULL returned: " + setStateRet.ToString());
        setStateRet = mCurrentPipeline.SetState(State.Ready);
        System.Diagnostics.Debug.WriteLine("SetStateReady returned: " + setStateRet.ToString());
        setStateRet = mCurrentPipeline.SetState(Gst.State.Playing); 
    }
    
     /// <summary>
    /// 
    /// </summary>
    /// <remarks>
    /// Indeed the application needs to set its Window identifier at the right time to avoid internal Window creation
    /// from the video sink element. To solve this issue a GstMessage is posted on the bus to inform the application
    /// that it should set the Window identifier immediately.
    /// 
    /// API: http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-base-libs/html/gst-plugins-base-libs-gstvideooverlay.html
    /// </remarks>
    /// <param name="o"></param>
    /// <param name="args"></param>
    private void bus_SyncMessage(object o, SyncMessageArgs args)
    {
        //Convenience function to check if the given message is a "prepare-window-handle" message from a GstVideoOverlay.
    
        System.Diagnostics.Debug.WriteLine("bus_SyncMessage: " + args.Message.Type.ToString());
        if (Gst.Video.Global.IsVideoOverlayPrepareWindowHandleMessage(args.Message))
        {
            Element src = (Gst.Element)args.Message.Src;
    
    #if DEBUG
            System.Diagnostics.Debug.WriteLine("Message'prepare-window-handle' received by: " + src.Name + " " + src.ToString());
    #endif
    
            if (src != null && (src is Gst.Video.VideoSink | src is Gst.Bin))
            {
                //    Try to set Aspect Ratio
                try
                {
                    src["force-aspect-ratio"] = true;
                }
                catch (PropertyNotFoundException) { }
    
                //    Try to set Overlay
                try
                {
                    Gst.Video.VideoOverlayAdapter overlay_ = new Gst.Video.VideoOverlayAdapter(src.Handle);
                    overlay_.WindowHandle = mHandle;                        
                    overlay_.HandleEvents(true);
                }
                catch (Exception ex) { System.Diagnostics.Debug.WriteLine("Exception thrown: " + ex.Message); }
            }
        }
    }
    
    private void HandleMessage (object o, MessageArgs args)
    {
        var msg = args.Message;
        //System.Diagnostics.Debug.WriteLine("HandleMessage received msg of type: {0}", msg.Type);
        switch (msg.Type)
        {
            case MessageType.Error:
                //
                GLib.GException err;
                string debug;
                System.Diagnostics.Debug.WriteLine("Error received: " + msg.ToString());
                //msg.ParseError (out err, out debug);
                //if(debug == null) { debug = "none"; }
                //System.Diagnostics.Debug.WriteLine ("Error received from element {0}: {1}", msg.Src, err.Message);
                //System.Diagnostics.Debug.WriteLine ("Debugging information: "+ debug);
                break;
            case MessageType.StreamStatus:
                Gst.StreamStatusType status;
                Element theOwner;
                msg.ParseStreamStatus(out status, out theOwner);
                System.Diagnostics.Debug.WriteLine("Case SteamingStatus: status is: " + status + " ; Ownder is: " + theOwner.Name);
                break;
            case MessageType.StateChanged:
                //System.Diagnostics.Debug.WriteLine("Case StateChanged: " + args.Message.ToString());
                State oldState, newState, pendingState;
                msg.ParseStateChanged(out oldState, out newState, out pendingState);
                if (newState == State.Paused)
                    args.RetVal = false;
                System.Diagnostics.Debug.WriteLine("Pipeline state changed from {0} to {1}: ; Pending: {2}", Element.StateGetName(oldState), Element.StateGetName(newState), Element.StateGetName(pendingState));
                break;
            case MessageType.Element:
                System.Diagnostics.Debug.WriteLine("Element message: {0}", args.Message.ToString());
                break;                
            default:
                System.Diagnostics.Debug.WriteLine("HandleMessage received msg of type: {0}", msg.Type);
                break;
        }
        args.RetVal = true;
    }