# GstVideoOverlay

The GstVideoOverlay interface is used for 2 main purposes :

- To get a grab on the Window where the video sink element is going to render. This is achieved by either being informed about the Window identifier that the video sink element generated, or by forcing the video sink element to use a specific Window identifier for rendering.
- To force a redrawing of the latest video frame the video sink element displayed on the Window. Indeed if the GstPipeline is in GST_STATE_PAUSED state, moving the Window around will damage its content. Application developers will want to handle the Expose events themselves and force the video sink element to refresh the Window's content.

Using the Window created by the video sink is probably the simplest scenario, in some cases, though, it might not be flexible enough for application developers if they need to catch events such as mouse moves and button clicks.

Setting a specific Window identifier on the video sink element is the most flexible solution but it has some issues. 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. Here is an example on how to do that correctly:

     static GstBusSyncReply
     create_window (GstBus * bus, GstMessage * message, GstPipeline * pipeline)
     {
      // ignore anything but 'prepare-window-handle' element messages
      if (!gst_is_video_overlay_prepare_window_handle_message (message))
        return GST_BUS_PASS;

      win = XCreateSimpleWindow (disp, root, 0, 0, 320, 240, 0, 0, 0);

      XSetWindowBackgroundPixmap (disp, win, None);

      XMapRaised (disp, win);

      XSync (disp, FALSE);

      gst_video_overlay_set_window_handle (GST_VIDEO_OVERLAY (GST_MESSAGE_SRC (message)),
          win);

      gst_message_unref (message);

      return GST_BUS_DROP;
     }
     ...
     int
     main (int argc, char **argv)
     {
     ...
      bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
      gst_bus_set_sync_handler (bus, (GstBusSyncHandler) create_window, pipeline,
            NULL);
     ...
     }

## Two basic usage scenarios

There are two basic usage scenarios: in the simplest case, the application uses playbin or playsink or knows exactly what particular element is used for video output, which is usually the case when the application creates the videosink to use (e.g. xvimagesink, ximagesink, etc.) itself; in this case, the application can just create the videosink element, create and realize the window to render the video on and then call gst_video_overlay_set_window_handle directly with the XID or native window handle, before starting up the pipeline. As playbin and playsink implement the video overlay interface and proxy it transparently to the actual video sink even if it is created later, this case also applies when using these elements.

In the other and more common case, the application does not know in advance what GStreamer video sink element will be used for video output. This is usually the case when an element such as autovideosink is used. In this case, the video sink element itself is created asynchronously from a GStreamer streaming thread some time after the pipeline has been started up. When that happens, however, the video sink will need to know right then whether to render onto an already existing application window or whether to create its own window. This is when it posts a prepare-window-handle message, and that is also why this message needs to be handled in a sync bus handler which will be called from the streaming thread directly (because the video sink will need an answer right then).

As response to the prepare-window-handle element message in the bus sync handler, the application may use gst_video_overlay_set_window_handle to tell the video sink to render onto an existing window surface. At this point the application should already have obtained the window handle / XID, so it just needs to set it. It is generally not advisable to call any GUI toolkit functions or window system functions from the streaming thread in which the prepare-window-handle message is handled, because most GUI toolkits and windowing systems are not thread-safe at all and a lot of care would be required to co-ordinate the toolkit and window system calls of the different threads (Gtk+ users please note: prior to Gtk+ 2.18 `GDK_WINDOW_XID` was just a simple structure access, so generally fine to do within the bus sync handler; this macro was changed to a function call in Gtk+ 2.18 and later, which is likely to cause problems when called from a sync handler; see below for a better approach without `GDK_WINDOW_XID` used in the callback).

## GstVideoOverlay and Gtk+

     #include <gst/video/videooverlay.h>
     #include <gtk/gtk.h>
     #ifdef GDK_WINDOWING_X11
     #include <gdk/gdkx.h>  // for GDK_WINDOW_XID
     #endif
     #ifdef GDK_WINDOWING_WIN32
     #include <gdk/gdkwin32.h>  // for GDK_WINDOW_HWND
     #endif
     ...
     static guintptr video_window_handle = 0;
     ...
     static GstBusSyncReply
     bus_sync_handler (GstBus * bus, GstMessage * message, gpointer user_data)
     {
      // ignore anything but 'prepare-window-handle' element messages
      if (!gst_is_video_overlay_prepare_window_handle_message (message))
        return GST_BUS_PASS;

      if (video_window_handle != 0) {
        GstVideoOverlay *overlay;

        // GST_MESSAGE_SRC (message) will be the video sink element
        overlay = GST_VIDEO_OVERLAY (GST_MESSAGE_SRC (message));
        gst_video_overlay_set_window_handle (overlay, video_window_handle);
      } else {
        g_warning ("Should have obtained video_window_handle by now!");
      }

      gst_message_unref (message);
      return GST_BUS_DROP;
     }
     ...
     static void
     video_widget_realize_cb (GtkWidget * widget, gpointer data)
     {
     #if GTK_CHECK_VERSION(2,18,0)
       // Tell Gtk+/Gdk to create a native window for this widget instead of
       // drawing onto the parent widget.
       // This is here just for pedagogical purposes, GDK_WINDOW_XID will call
       // it as well in newer Gtk versions
       if (!gdk_window_ensure_native (widget->window))
         g_error ("Couldn't create native window needed for GstVideoOverlay!");
     #endif

     #ifdef GDK_WINDOWING_X11
       {
         gulong xid = GDK_WINDOW_XID (gtk_widget_get_window (video_window));
         video_window_handle = xid;
       }
     #endif
     #ifdef GDK_WINDOWING_WIN32
       {
         HWND wnd = GDK_WINDOW_HWND (gtk_widget_get_window (video_window));
         video_window_handle = (guintptr) wnd;
       }
     #endif
     }
     ...
     int
     main (int argc, char **argv)
     {
       GtkWidget *video_window;
       GtkWidget *app_window;
       ...
       app_window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
       ...
       video_window = gtk_drawing_area_new ();
       g_signal_connect (video_window, "realize",
           G_CALLBACK (video_widget_realize_cb), NULL);
       gtk_widget_set_double_buffered (video_window, FALSE);
       ...
       // usually the video_window will not be directly embedded into the
       // application window like this, but there will be many other widgets
       // and the video window will be embedded in one of them instead
       gtk_container_add (GTK_CONTAINER (ap_window), video_window);
       ...
       // show the GUI
       gtk_widget_show_all (app_window);

       // realize window now so that the video window gets created and we can
       // obtain its XID/HWND before the pipeline is started up and the videosink
       // asks for the XID/HWND of the window to render onto
       gtk_widget_realize (video_window);

       // we should have the XID/HWND now
       g_assert (video_window_handle != 0);
       ...
       // set up sync handler for setting the xid once the pipeline is started
       bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
       gst_bus_set_sync_handler (bus, (GstBusSyncHandler) bus_sync_handler, NULL,
           NULL);
       gst_object_unref (bus);
       ...
       gst_element_set_state (pipeline, GST_STATE_PLAYING);
       ...
     }

## GstVideoOverlay and Qt

     #include <glib.h>;
     #include <gst/gst.h>;
     #include <gst/video/videooverlay.h>;

     #include <QApplication>;
     #include <QTimer>;
     #include <QWidget>;

     int main(int argc, char *argv[])
     {
       if (!g_thread_supported ())
         g_thread_init (NULL);

       gst_init (&argc, &argv);
       QApplication app(argc, argv);
       app.connect(&app, SIGNAL(lastWindowClosed()), &app, SLOT(quit ()));

       // prepare the pipeline

       GstElement *pipeline = gst_pipeline_new ("xvoverlay");
       GstElement *src = gst_element_factory_make ("videotestsrc", NULL);
       GstElement *sink = gst_element_factory_make ("xvimagesink", NULL);
       gst_bin_add_many (GST_BIN (pipeline), src, sink, NULL);
       gst_element_link (src, sink);

       // prepare the ui

       QWidget window;
       window.resize(320, 240);
       window.show();

       WId xwinid = window.winId();
       gst_video_overlay_set_window_handle (GST_VIDEO_OVERLAY (sink), xwinid);

       // run the pipeline

       GstStateChangeReturn sret = gst_element_set_state (pipeline,
           GST_STATE_PLAYING);
       if (sret == GST_STATE_CHANGE_FAILURE) {
         gst_element_set_state (pipeline, GST_STATE_NULL);
         gst_object_unref (pipeline);
         // Exit application
         QTimer::singleShot(0, QApplication::activeWindow(), SLOT(quit()));
       }

       int ret = app.exec();

       window.hide();
       gst_element_set_state (pipeline, GST_STATE_NULL);
       gst_object_unref (pipeline);

       return ret;
     }

## GstVideoOverlay

Opaque GstVideoOverlay interface structure

## GstVideo.VideoOverlay

Opaque GstVideo.VideoOverlay interface structure

## GstVideo.VideoOverlay

Opaque GstVideo.VideoOverlay interface structure

### Methods

#### gst_video_overlay_expose

    gst_video_overlay_expose (GstVideoOverlay * overlay)

Tell an overlay that it has been exposed. This will redraw the current frame in the drawable even if the pipeline is PAUSED.

Parameters:

`overlay` –

a GstVideoOverlay to expose.

#### GstVideo.VideoOverlay.prototype.expose

    function GstVideo.VideoOverlay.prototype.expose(): {
        // javascript wrapper for 'gst_video_overlay_expose'
    }

Tell an overlay that it has been exposed. This will redraw the current frame in the drawable even if the pipeline is PAUSED.

Parameters:

`overlay` (GstVideo.VideoOverlay) –

a GstVideo.VideoOverlay to expose.

#### GstVideo.VideoOverlay.expose

    def GstVideo.VideoOverlay.expose (self):
        #python wrapper for 'gst_video_overlay_expose'

Tell an overlay that it has been exposed. This will redraw the current frame in the drawable even if the pipeline is PAUSED.

Parameters:

`overlay` (GstVideo.VideoOverlay) –

a GstVideo.VideoOverlay to expose.

#### gst_video_overlay_got_window_handle

    gst_video_overlay_got_window_handle (GstVideoOverlay * overlay,
                                         guintptr handle)

This will post a "have-window-handle" element message on the bus.

This function should only be used by video overlay plugin developers.

Parameters:

`overlay` –

a GstVideoOverlay which got a window

`handle` –

a platform-specific handle referencing the window

#### GstVideo.VideoOverlay.prototype.got_window_handle

    function GstVideo.VideoOverlay.prototype.got_window_handle(handle: Number): {
        // javascript wrapper for 'gst_video_overlay_got_window_handle'
    }

This will post a "have-window-handle" element message on the bus.

This function should only be used by video overlay plugin developers.

Parameters:

`overlay` (GstVideo.VideoOverlay) –

a GstVideo.VideoOverlay which got a window

`handle` (Number) –

a platform-specific handle referencing the window

#### GstVideo.VideoOverlay.got_window_handle

    def GstVideo.VideoOverlay.got_window_handle (self, handle):
        #python wrapper for 'gst_video_overlay_got_window_handle'

This will post a "have-window-handle" element message on the bus.

This function should only be used by video overlay plugin developers.

Parameters:

`overlay` (GstVideo.VideoOverlay) –

a GstVideo.VideoOverlay which got a window

`handle` (int) –

a platform-specific handle referencing the window

#### gst_video_overlay_handle_events

    gst_video_overlay_handle_events (GstVideoOverlay * overlay,
                                     gboolean handle_events)

Tell an overlay that it should handle events from the window system. These events are forwarded upstream as navigation events. In some window system, events are not propagated in the window hierarchy if a client is listening for them. This method allows you to disable events handling completely from the GstVideoOverlay.

Parameters:

`overlay` –

a GstVideoOverlay to expose.

`handle_events` –

a gboolean indicating if events should be handled or not.

#### GstVideo.VideoOverlay.prototype.handle_events

    function GstVideo.VideoOverlay.prototype.handle_events(handle_events: Number): {
        // javascript wrapper for 'gst_video_overlay_handle_events'
    }

Tell an overlay that it should handle events from the window system. These events are forwarded upstream as navigation events. In some window system, events are not propagated in the window hierarchy if a client is listening for them. This method allows you to disable events handling completely from the GstVideo.VideoOverlay.

Parameters:

`overlay` (GstVideo.VideoOverlay) –

a GstVideo.VideoOverlay to expose.

`handle_events` (Number) –

a gboolean indicating if events should be handled or not.

#### GstVideo.VideoOverlay.handle_events

    def GstVideo.VideoOverlay.handle_events (self, handle_events):
        #python wrapper for 'gst_video_overlay_handle_events'

Tell an overlay that it should handle events from the window system. These events are forwarded upstream as navigation events. In some window system, events are not propagated in the window hierarchy if a client is listening for them. This method allows you to disable events handling completely from the GstVideo.VideoOverlay.

Parameters:

`overlay` (GstVideo.VideoOverlay) –

a GstVideo.VideoOverlay to expose.

`handle_events` (bool) –

a gboolean indicating if events should be handled or not.

#### gst_video_overlay_prepare_window_handle

    gst_video_overlay_prepare_window_handle (GstVideoOverlay * overlay)

This will post a "prepare-window-handle" element message on the bus to give applications an opportunity to call gst_video_overlay_set_window_handle before a plugin creates its own window.

This function should only be used by video overlay plugin developers.

Parameters:

`overlay` –

a GstVideoOverlay which does not yet have an Window handle set

#### GstVideo.VideoOverlay.prototype.prepare_window_handle

    function GstVideo.VideoOverlay.prototype.prepare_window_handle(): {
        // javascript wrapper for 'gst_video_overlay_prepare_window_handle'
    }

This will post a "prepare-window-handle" element message on the bus to give applications an opportunity to call GstVideo.VideoOverlay.prototype.set_window_handle before a plugin creates its own window.

This function should only be used by video overlay plugin developers.

Parameters:

`overlay` (GstVideo.VideoOverlay) –

a GstVideo.VideoOverlay which does not yet have an Window handle set

#### GstVideo.VideoOverlay.prepare_window_handle

    def GstVideo.VideoOverlay.prepare_window_handle (self):
        #python wrapper for 'gst_video_overlay_prepare_window_handle'

This will post a "prepare-window-handle" element message on the bus to give applications an opportunity to call GstVideo.VideoOverlay.set_window_handle before a plugin creates its own window.

This function should only be used by video overlay plugin developers.

Parameters:

`overlay` (GstVideo.VideoOverlay) –

a GstVideo.VideoOverlay which does not yet have an Window handle set

#### gst_video_overlay_set_render_rectangle

    gboolean
    gst_video_overlay_set_render_rectangle (GstVideoOverlay * overlay,
                                            gint x,
                                            gint y,
                                            gint width,
                                            gint height)

Configure a subregion as a video target within the window set by gst_video_overlay_set_window_handle. If this is not used or not supported the video will fill the area of the window set as the overlay to 100%. By specifying the rectangle, the video can be overlayed to a specific region of that window only. After setting the new rectangle one should call gst_video_overlay_expose to force a redraw. To unset the region pass -1 for the width and height parameters.

This method is needed for non fullscreen video overlay in UI toolkits that do not support subwindows.

Parameters:

`overlay` –

a GstVideoOverlay

`x` –

the horizontal offset of the render area inside the window

`y` –

the vertical offset of the render area inside the window

`width` –

the width of the render area inside the window

`height` –

the height of the render area inside the window

Returns –

FALSE if not supported by the sink.

#### GstVideo.VideoOverlay.prototype.set_render_rectangle

    function GstVideo.VideoOverlay.prototype.set_render_rectangle(x: Number, y: Number, width: Number, height: Number): {
        // javascript wrapper for 'gst_video_overlay_set_render_rectangle'
    }

Configure a subregion as a video target within the window set by GstVideo.VideoOverlay.prototype.set_window_handle. If this is not used or not supported the video will fill the area of the window set as the overlay to 100%. By specifying the rectangle, the video can be overlayed to a specific region of that window only. After setting the new rectangle one should call GstVideo.VideoOverlay.prototype.expose to force a redraw. To unset the region pass -1 for the width and height parameters.

This method is needed for non fullscreen video overlay in UI toolkits that do not support subwindows.

Parameters:

`overlay` (GstVideo.VideoOverlay) –

a GstVideo.VideoOverlay

`x` (Number) –

the horizontal offset of the render area inside the window

`y` (Number) –

the vertical offset of the render area inside the window

`width` (Number) –

the width of the render area inside the window

`height` (Number) –

the height of the render area inside the window

Returns (Number) –

FALSE if not supported by the sink.

#### GstVideo.VideoOverlay.set_render_rectangle

    def GstVideo.VideoOverlay.set_render_rectangle (self, x, y, width, height):
        #python wrapper for 'gst_video_overlay_set_render_rectangle'

Configure a subregion as a video target within the window set by GstVideo.VideoOverlay.set_window_handle. If this is not used or not supported the video will fill the area of the window set as the overlay to 100%. By specifying the rectangle, the video can be overlayed to a specific region of that window only. After setting the new rectangle one should call GstVideo.VideoOverlay.expose to force a redraw. To unset the region pass -1 for the width and height parameters.

This method is needed for non fullscreen video overlay in UI toolkits that do not support subwindows.

Parameters:

`overlay` (GstVideo.VideoOverlay) –

a GstVideo.VideoOverlay

`x` (int) –

the horizontal offset of the render area inside the window

`y` (int) –

the vertical offset of the render area inside the window

`width` (int) –

the width of the render area inside the window

`height` (int) –

the height of the render area inside the window

Returns (bool) –

FALSE if not supported by the sink.

#### gst_video_overlay_set_window_handle

    gst_video_overlay_set_window_handle (GstVideoOverlay * overlay,
                                         guintptr handle)

This will call the video overlay's set_window_handle method. You should use this method to tell to an overlay to display video output to a specific window (e.g. an XWindow on X11). Passing 0 as the handle will tell the overlay to stop using that window and create an internal one.

Parameters:

`overlay` –

a GstVideoOverlay to set the window on.

`handle` –

a handle referencing the window.

#### GstVideo.VideoOverlay.prototype.set_window_handle

    function GstVideo.VideoOverlay.prototype.set_window_handle(handle: Number): {
        // javascript wrapper for 'gst_video_overlay_set_window_handle'
    }

This will call the video overlay's set_window_handle method. You should use this method to tell to an overlay to display video output to a specific window (e.g. an XWindow on X11). Passing 0 as the handle will tell the overlay to stop using that window and create an internal one.

Parameters:

`overlay` (GstVideo.VideoOverlay) –

a GstVideo.VideoOverlay to set the window on.

`handle` (Number) –

a handle referencing the window.

#### GstVideo.VideoOverlay.set_window_handle

    def GstVideo.VideoOverlay.set_window_handle (self, handle):
        #python wrapper for 'gst_video_overlay_set_window_handle'

This will call the video overlay's set_window_handle method. You should use this method to tell to an overlay to display video output to a specific window (e.g. an XWindow on X11). Passing 0 as the handle will tell the overlay to stop using that window and create an internal one.

Parameters:

`overlay` (GstVideo.VideoOverlay) –

a GstVideo.VideoOverlay to set the window on.

`handle` (int) –

a handle referencing the window.

### Functions

#### gst_video_overlay_install_properties

    gst_video_overlay_install_properties (GObjectClass* oclass,
                                          gint last_prop_id)

This helper shall be used by classes implementing the GstVideoOverlay interface that want the render rectangle to be controllable using properties. This helper will install "render-rectangle" property into the class.

Parameters:

`oclass` –

The class on which the properties will be installed

`last_prop_id` –

The first free property ID to use

Since : 1.14

#### GstVideo.prototype.video_overlay_install_properties

    function GstVideo.prototype.video_overlay_install_properties(oclass: GObject.ObjectClass, last_prop_id: Number): {
        // javascript wrapper for 'gst_video_overlay_install_properties'
    }

This helper shall be used by classes implementing the GstVideo.VideoOverlay interface that want the render rectangle to be controllable using properties. This helper will install "render-rectangle" property into the class.

Parameters:

`oclass` (GObject.ObjectClass) –

The class on which the properties will be installed

`last_prop_id` (Number) –

The first free property ID to use

Since : 1.14

#### GstVideo.video_overlay_install_properties

    def GstVideo.video_overlay_install_properties (oclass, last_prop_id):
        #python wrapper for 'gst_video_overlay_install_properties'

This helper shall be used by classes implementing the GstVideo.VideoOverlay interface that want the render rectangle to be controllable using properties. This helper will install "render-rectangle" property into the class.

Parameters:

`oclass` (GObject.ObjectClass) –

The class on which the properties will be installed

`last_prop_id` (int) –

The first free property ID to use

Since : 1.14

#### gst_video_overlay_set_property

    gboolean
    gst_video_overlay_set_property (GObject * object,
                                    gint last_prop_id,
                                    guint property_id,
                                    const GValue * value)

This helper shall be used by classes implementing the GstVideoOverlay interface that want the render rectangle to be controllable using properties. This helper will parse and set the render rectangle calling gst_video_overlay_set_render_rectangle.

Parameters:

`object` –

The instance on which the property is set

`last_prop_id` –

The highest property ID.

`property_id` –

The property ID

`value` –

The GValue to be set

Returns –

TRUE if the property_id matches the GstVideoOverlay property

Since : 1.14

#### GstVideo.prototype.video_overlay_set_property

    function GstVideo.prototype.video_overlay_set_property(object: GObject.Object, last_prop_id: Number, property_id: Number, value: GObject.Value): {
        // javascript wrapper for 'gst_video_overlay_set_property'
    }

This helper shall be used by classes implementing the GstVideo.VideoOverlay interface that want the render rectangle to be controllable using properties. This helper will parse and set the render rectangle calling GstVideo.VideoOverlay.prototype.set_render_rectangle.

Parameters:

`object` (GObject.Object) –

The instance on which the property is set

`last_prop_id` (Number) –

The highest property ID.

`property_id` (Number) –

The property ID

`value` (GObject.Value) –

The GObject.Value to be set

Returns (Number) –

TRUE if the property_id matches the GstVideoOverlay property

Since : 1.14

#### GstVideo.video_overlay_set_property

    def GstVideo.video_overlay_set_property (object, last_prop_id, property_id, value):
        #python wrapper for 'gst_video_overlay_set_property'

This helper shall be used by classes implementing the GstVideo.VideoOverlay interface that want the render rectangle to be controllable using properties. This helper will parse and set the render rectangle calling GstVideo.VideoOverlay.set_render_rectangle.

Parameters:

`object` (GObject.Object) –

The instance on which the property is set

`last_prop_id` (int) –

The highest property ID.

`property_id` (int) –

The property ID

`value` (GObject.Value) –

The GObject.Value to be set

Returns (bool) –

TRUE if the property_id matches the GstVideoOverlay property

Since : 1.14

### Virtual Methods

#### expose

    expose (GstVideoOverlay * overlay)

virtual method to handle expose events

Parameters:

`overlay` –
No description available

#### vfunc_expose

    function vfunc_expose(overlay: GstVideo.VideoOverlay): {
        // javascript implementation of the 'expose' virtual method
    }

virtual method to handle expose events

Parameters:

`overlay` (GstVideo.VideoOverlay) –
No description available

#### do_expose

    def do_expose (overlay):
        #python implementation of the 'expose' virtual method

virtual method to handle expose events

Parameters:

`overlay` (GstVideo.VideoOverlay) –
No description available

#### handle_events

    handle_events (GstVideoOverlay * overlay,
                   gboolean handle_events)

virtual method to handle events

Parameters:

`overlay` –
No description available
`handle_events` –
No description available

#### vfunc_handle_events

    function vfunc_handle_events(overlay: GstVideo.VideoOverlay, handle_events: Number): {
        // javascript implementation of the 'handle_events' virtual method
    }

virtual method to handle events

Parameters:

`overlay` (GstVideo.VideoOverlay) –
No description available
`handle_events` (Number) –
No description available

#### do_handle_events

    def do_handle_events (overlay, handle_events):
        #python implementation of the 'handle_events' virtual method

virtual method to handle events

Parameters:

`overlay` (GstVideo.VideoOverlay) –
No description available
`handle_events` (bool) –
No description available

#### set_render_rectangle

    set_render_rectangle (GstVideoOverlay * overlay,
                          gint x,
                          gint y,
                          gint width,
                          gint height)

virtual method to set the render rectangle

Parameters:

`overlay` –
No description available
`x` –
No description available
`y` –
No description available
`width` –
No description available
`height` –
No description available

#### vfunc_set_render_rectangle

    function vfunc_set_render_rectangle(overlay: GstVideo.VideoOverlay, x: Number, y: Number, width: Number, height: Number): {
        // javascript implementation of the 'set_render_rectangle' virtual method
    }

virtual method to set the render rectangle

Parameters:

`overlay` (GstVideo.VideoOverlay) –
No description available
`x` (Number) –
No description available
`y` (Number) –
No description available
`width` (Number) –
No description available
`height` (Number) –
No description available

#### do_set_render_rectangle

    def do_set_render_rectangle (overlay, x, y, width, height):
        #python implementation of the 'set_render_rectangle' virtual method

virtual method to set the render rectangle

Parameters:

`overlay` (GstVideo.VideoOverlay) –
No description available
`x` (int) –
No description available
`y` (int) –
No description available
`width` (int) –
No description available
`height` (int) –
No description available

#### set_window_handle

    set_window_handle (GstVideoOverlay * overlay,
                       guintptr handle)

virtual method to configure the window handle

Parameters:

`overlay` –
No description available
`handle` –
No description available

#### vfunc_set_window_handle

    function vfunc_set_window_handle(overlay: GstVideo.VideoOverlay, handle: Number): {
        // javascript implementation of the 'set_window_handle' virtual method
    }

virtual method to configure the window handle

Parameters:

`overlay` (GstVideo.VideoOverlay) –
No description available
`handle` (Number) –
No description available

#### do_set_window_handle

    def do_set_window_handle (overlay, handle):
        #python implementation of the 'set_window_handle' virtual method

virtual method to configure the window handle

Parameters:

`overlay` (GstVideo.VideoOverlay) –
No description available
`handle` (int) –
No description available

## Functions

### gst_is_video_overlay_prepare_window_handle_message

    gboolean
    gst_is_video_overlay_prepare_window_handle_message (GstMessage * msg)

Convenience function to check if the given message is a "prepare-window-handle" message from a GstVideoOverlay.

Parameters:

`msg` –

a GstMessage

Returns –

whether msg is a "prepare-window-handle" message

### GstVideo.prototype.is_video_overlay_prepare_window_handle_message

    function GstVideo.prototype.is_video_overlay_prepare_window_handle_message(msg: Gst.Message): {
        // javascript wrapper for 'gst_is_video_overlay_prepare_window_handle_message'
    }

Convenience function to check if the given message is a "prepare-window-handle" message from a GstVideo.VideoOverlay.

Parameters:

`msg` (Gst.Message) –

a Gst.Message

Returns (Number) –

whether msg is a "prepare-window-handle" message

### GstVideo.is_video_overlay_prepare_window_handle_message

    def GstVideo.is_video_overlay_prepare_window_handle_message (msg):
        #python wrapper for 'gst_is_video_overlay_prepare_window_handle_message'

Convenience function to check if the given message is a "prepare-window-handle" message from a GstVideo.VideoOverlay.

Parameters:

`msg` (Gst.Message) –

a Gst.Message

Returns (bool) –

whether msg is a "prepare-window-handle" message

## Function Macros

### GST_VIDEO_OVERLAY_GET_INTERFACE

    #define GST_VIDEO_OVERLAY_GET_INTERFACE(inst) \
        (G_TYPE_INSTANCE_GET_INTERFACE ((inst), GST_TYPE_VIDEO_OVERLAY, GstVideoOverlayInterface))

## Constants

### GST_TYPE_VIDEO_OVERLAY

    #define GST_TYPE_VIDEO_OVERLAY \
        (gst_video_overlay_get_type ())

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