Using GstVideoOverlay on Mac

[Andy Robinson]

Mac OS 10.10
GStreamer 1.6.1
Xcode 6.4

Hello, can anyone point me to any sample code (C/C++) showing how to 
display video on the Mac, in a window owned by the application (rather 
than GStreamer creating a window for the video)?

I have written code (using wxWidgets as it happens) which works fine on 
Linux/GTK and on Windows.

I have a top-level window containing a child control in which I want the 
video to appear. I get a handle like this:

#ifdef __WXGTK__
    GtkWidget *gtk_widget = m_wxwindow;
    GdkWindow *gdk_window = gtk_widget_get_window(gtk_widget);
    gdk_window_ensure_native(gdk_window));
    m_video_window_handle = GDK_WINDOW_XID(gdk_window);
#endif

#ifdef __WXMSW__
    m_video_window_handle = (gulong)GetHWND();
#endif

#ifdef __WXMAC__
    NSView *nsv = GetPeer()->GetWXWidget();
    m_video_window_handle = (gulong)nsv;
#endif

The wxWidgets people assure me that this will obtain a NSView* on Mac.

Then in the bus_sync_callback I do:
    GstVideoOverlay *overlay = GST_VIDEO_OVERLAY(GST_MESSAGE_SRC(msg));
    gst_video_overlay_set_window_handle(overlay, m_video_window_handle);

As I say, this works on Windows & Linux. But on Mac the place where the 
video should be, is blank.

If I omit the call to gst_video_overlay_set_window_handle then GStreamer 
creates a new window and displays the video in it. But I want the video 
to appear in my already-existing window.

So maybe I am passing the wrong thing to 
gst_video_overlay_set_window_handle. But if so then I don't know what I 
am doing wrong so if anyone can suggest anything, or point me to an 
example which works, I'd be most grateful.

Regards,
Andy Robinson, Seventh String Software, www.seventhstring.com