c# - 在 WinForms 中显示 gstreamer-sharp 视频流

Question

我正在寻找在 WinForms 应用程序中显示 gstreamer-sharp feed 的示例/帮助。

我正在使用 VS 2012，并为此版本的 VS 构建了“glue”项目。我还安装了 glib-sharp、gstreamer-sharp，并被我的项目引用。我将 gstreamer bin 目录设置为项目的工作目录。

如果按钮单击处理程序中有以下代码，我会得到 GStreamer D3D 视频接收器测试窗口，该窗口会在我的表单顶部弹出。

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

我想让流在我的应用程序中显示在我正在考虑的面板或 PictureBox 上。

谢谢!

Answer 1

下面的代码将使测试流显示在 WinForm 的面板控件上。

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;
}