ext/gtk/gstgtksink.c - mtk-gst-plugins-bad-debian - Git at Google

 /*
  * GStreamer
  * Copyright (C) 2015 Matthew Waters <matthew@centricular.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public
  * License along with this library; if not, write to the
  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */

 /**
  * SECTION:gtkgstsink
  *
  */

 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif

 #include "gstgtksink.h"

 GST_DEBUG_CATEGORY (gst_debug_gtk_sink);
 #define GST_CAT_DEFAULT gst_debug_gtk_sink

 static void gst_gtk_sink_finalize (GObject * object);
 static void gst_gtk_sink_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * param_spec);
 static void gst_gtk_sink_get_property (GObject * object, guint prop_id,
     GValue * value, GParamSpec * param_spec);

 static gboolean gst_gtk_sink_stop (GstBaseSink * bsink);

 static gboolean gst_gtk_sink_query (GstBaseSink * bsink, GstQuery * query);

 static GstStateChangeReturn
 gst_gtk_sink_change_state (GstElement * element, GstStateChange transition);

 static void gst_gtk_sink_get_times (GstBaseSink * bsink, GstBuffer * buf,
     GstClockTime * start, GstClockTime * end);
 static gboolean gst_gtk_sink_set_caps (GstBaseSink * bsink, GstCaps * caps);
 static GstFlowReturn gst_gtk_sink_show_frame (GstVideoSink * bsink,
     GstBuffer * buf);

 #if G_BYTE_ORDER == G_LITTLE_ENDIAN
 #define FORMATS "{ BGRx, BGRA }"
 #else
 #define FORMATS "{ xRGB, ARGB }"
 #endif

 static GstStaticPadTemplate gst_gtk_sink_template =
 GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
     GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE (FORMATS))
     );

 #define DEFAULT_FORCE_ASPECT_RATIO  TRUE
 #define DEFAULT_PAR_N               0
 #define DEFAULT_PAR_D               1
 #define DEFAULT_IGNORE_ALPHA        TRUE

 enum
 {
   PROP_0,
   PROP_WIDGET,
   PROP_FORCE_ASPECT_RATIO,
   PROP_PIXEL_ASPECT_RATIO,
   PROP_IGNORE_ALPHA,
 };

 enum
 {
   SIGNAL_0,
   LAST_SIGNAL
 };

 #define gst_gtk_sink_parent_class parent_class
 G_DEFINE_TYPE_WITH_CODE (GstGtkSink, gst_gtk_sink,
     GST_TYPE_VIDEO_SINK, GST_DEBUG_CATEGORY_INIT (gst_debug_gtk_sink, "gtksink",
         0, "Gtk Video Sink"));

 static void
 gst_gtk_sink_class_init (GstGtkSinkClass * klass)
 {
   GObjectClass *gobject_class;
   GstElementClass *gstelement_class;
   GstBaseSinkClass *gstbasesink_class;
   GstVideoSinkClass *gstvideosink_class;

   gobject_class = (GObjectClass *) klass;
   gstelement_class = (GstElementClass *) klass;
   gstbasesink_class = (GstBaseSinkClass *) klass;
   gstvideosink_class = (GstVideoSinkClass *) klass;

   gobject_class->set_property = gst_gtk_sink_set_property;
   gobject_class->get_property = gst_gtk_sink_get_property;

   gst_element_class_set_metadata (gstelement_class, "Gtk Video Sink",
       "Sink/Video", "A video sink that renders to a GtkWidget",
       "Matthew Waters <matthew@centricular.com>");

   g_object_class_install_property (gobject_class, PROP_WIDGET,
       g_param_spec_object ("widget", "Gtk Widget",
           "The GtkWidget to place in the widget heirachy",
           GTK_TYPE_WIDGET, G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));

   g_object_class_install_property (gobject_class, PROP_FORCE_ASPECT_RATIO,
       g_param_spec_boolean ("force-aspect-ratio",
           "Force aspect ratio",
           "When enabled, scaling will respect original aspect ratio",
           DEFAULT_FORCE_ASPECT_RATIO,
           G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

   g_object_class_install_property (gobject_class, PROP_PIXEL_ASPECT_RATIO,
       gst_param_spec_fraction ("pixel-aspect-ratio", "Pixel Aspect Ratio",
           "The pixel aspect ratio of the device", DEFAULT_PAR_N, DEFAULT_PAR_D,
           G_MAXINT, 1, 1, 1, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

   g_object_class_install_property (gobject_class, PROP_IGNORE_ALPHA,
       g_param_spec_boolean ("ignore-alpha", "Ignore Alpha",
           "When enabled, alpha will be ignored and converted to black",
           DEFAULT_IGNORE_ALPHA, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

   gst_element_class_add_pad_template (gstelement_class,
       gst_static_pad_template_get (&gst_gtk_sink_template));

   gobject_class->finalize = gst_gtk_sink_finalize;

   gstelement_class->change_state = gst_gtk_sink_change_state;
   gstbasesink_class->query = gst_gtk_sink_query;
   gstbasesink_class->set_caps = gst_gtk_sink_set_caps;
   gstbasesink_class->get_times = gst_gtk_sink_get_times;
   gstbasesink_class->stop = gst_gtk_sink_stop;

   gstvideosink_class->show_frame = gst_gtk_sink_show_frame;
 }

 static void
 gst_gtk_sink_init (GstGtkSink * gtk_sink)
 {
   gtk_sink->force_aspect_ratio = DEFAULT_FORCE_ASPECT_RATIO;
   gtk_sink->par_n = DEFAULT_PAR_N;
   gtk_sink->par_d = DEFAULT_PAR_D;
   gtk_sink->ignore_alpha = DEFAULT_IGNORE_ALPHA;
 }

 static void
 gst_gtk_sink_finalize (GObject * object)
 {
   GstGtkSink *gtk_sink = GST_GTK_SINK (object);;

   g_object_unref (gtk_sink->widget);

   G_OBJECT_CLASS (parent_class)->finalize (object);
 }

 static GtkGstWidget *
 gst_gtk_sink_get_widget (GstGtkSink * gtk_sink)
 {
   if (gtk_sink->widget != NULL)
     return gtk_sink->widget;

   /* Ensure GTK is initialized, this has no side effect if it was already
    * initialized. Also, we do that lazily, so the application can be first */
   if (!gtk_init_check (NULL, NULL)) {
     GST_ERROR_OBJECT (gtk_sink, "Could not ensure GTK initialization.");
     return NULL;
   }

   gtk_sink->widget = (GtkGstWidget *) gtk_gst_widget_new ();
   gtk_sink->bind_aspect_ratio =
       g_object_bind_property (gtk_sink, "force-aspect-ratio", gtk_sink->widget,
       "force-aspect-ratio", G_BINDING_BIDIRECTIONAL | G_BINDING_SYNC_CREATE);
   gtk_sink->bind_pixel_aspect_ratio =
       g_object_bind_property (gtk_sink, "pixel-aspect-ratio", gtk_sink->widget,
       "pixel-aspect-ratio", G_BINDING_BIDIRECTIONAL | G_BINDING_SYNC_CREATE);
   gtk_sink->bind_ignore_alpha =
       g_object_bind_property (gtk_sink, "ignore-alpha", gtk_sink->widget,
       "ignore-alpha", G_BINDING_BIDIRECTIONAL | G_BINDING_SYNC_CREATE);

   /* Take the floating ref, other wise the destruction of the container will
    * make this widget disapear possibly before we are done. */
   gst_object_ref_sink (gtk_sink->widget);

   return gtk_sink->widget;
 }

 static void
 gst_gtk_sink_get_property (GObject * object, guint prop_id,
     GValue * value, GParamSpec * pspec)
 {
   GstGtkSink *gtk_sink = GST_GTK_SINK (object);

   switch (prop_id) {
     case PROP_WIDGET:
       g_value_set_object (value, gst_gtk_sink_get_widget (gtk_sink));
       break;
     case PROP_FORCE_ASPECT_RATIO:
       g_value_set_boolean (value, gtk_sink->force_aspect_ratio);
       break;
     case PROP_PIXEL_ASPECT_RATIO:
       gst_value_set_fraction (value, gtk_sink->par_n, gtk_sink->par_d);
       break;
     case PROP_IGNORE_ALPHA:
       g_value_set_boolean (value, gtk_sink->ignore_alpha);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
   }
 }

 static void
 gst_gtk_sink_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec)
 {
   GstGtkSink *gtk_sink = GST_GTK_SINK (object);

   switch (prop_id) {
     case PROP_FORCE_ASPECT_RATIO:
       gtk_sink->force_aspect_ratio = g_value_get_boolean (value);
       break;
     case PROP_PIXEL_ASPECT_RATIO:
       gtk_sink->par_n = gst_value_get_fraction_numerator (value);
       gtk_sink->par_d = gst_value_get_fraction_denominator (value);
       break;
     case PROP_IGNORE_ALPHA:
       gtk_sink->ignore_alpha = g_value_get_boolean (value);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
   }
 }

 static gboolean
 gst_gtk_sink_query (GstBaseSink * bsink, GstQuery * query)
 {
   gboolean res = FALSE;

   switch (GST_QUERY_TYPE (query)) {
     default:
       res = GST_BASE_SINK_CLASS (parent_class)->query (bsink, query);
       break;
   }

   return res;
 }

 static gboolean
 gst_gtk_sink_stop (GstBaseSink * bsink)
 {
   return TRUE;
 }

 static GstStateChangeReturn
 gst_gtk_sink_change_state (GstElement * element, GstStateChange transition)
 {
   GstGtkSink *gtk_sink = GST_GTK_SINK (element);
   GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;

   GST_DEBUG ("changing state: %s => %s",
       gst_element_state_get_name (GST_STATE_TRANSITION_CURRENT (transition)),
       gst_element_state_get_name (GST_STATE_TRANSITION_NEXT (transition)));

   switch (transition) {
     case GST_STATE_CHANGE_NULL_TO_READY:
       if (gst_gtk_sink_get_widget (gtk_sink) == NULL)
         return GST_STATE_CHANGE_FAILURE;
       break;
     case GST_STATE_CHANGE_READY_TO_PAUSED:
       break;
     case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
       break;
     default:
       break;
   }

   ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
   if (ret == GST_STATE_CHANGE_FAILURE)
     return ret;

   switch (transition) {
     case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
       break;
     case GST_STATE_CHANGE_PAUSED_TO_READY:
       gtk_gst_widget_set_buffer (gtk_sink->widget, NULL);
       break;
     case GST_STATE_CHANGE_READY_TO_NULL:
       break;
     default:
       break;
   }

   return ret;
 }

 static void
 gst_gtk_sink_get_times (GstBaseSink * bsink, GstBuffer * buf,
     GstClockTime * start, GstClockTime * end)
 {
   GstGtkSink *gtk_sink;

   gtk_sink = GST_GTK_SINK (bsink);

   if (GST_BUFFER_TIMESTAMP_IS_VALID (buf)) {
     *start = GST_BUFFER_TIMESTAMP (buf);
     if (GST_BUFFER_DURATION_IS_VALID (buf))
       *end = *start + GST_BUFFER_DURATION (buf);
     else {
       if (GST_VIDEO_INFO_FPS_N (&gtk_sink->v_info) > 0) {
         *end = *start +
             gst_util_uint64_scale_int (GST_SECOND,
             GST_VIDEO_INFO_FPS_D (&gtk_sink->v_info),
             GST_VIDEO_INFO_FPS_N (&gtk_sink->v_info));
       }
     }
   }
 }

 gboolean
 gst_gtk_sink_set_caps (GstBaseSink * bsink, GstCaps * caps)
 {
   GstGtkSink *gtk_sink = GST_GTK_SINK (bsink);

   GST_DEBUG ("set caps with %" GST_PTR_FORMAT, caps);

   if (!gst_video_info_from_caps (&gtk_sink->v_info, caps))
     return FALSE;

   if (!gtk_gst_widget_set_caps (gtk_sink->widget, caps))
     return FALSE;

   return TRUE;
 }

 static GstFlowReturn
 gst_gtk_sink_show_frame (GstVideoSink * vsink, GstBuffer * buf)
 {
   GstGtkSink *gtk_sink;

   GST_TRACE ("rendering buffer:%p", buf);

   gtk_sink = GST_GTK_SINK (vsink);

   if (gtk_sink->widget)
     gtk_gst_widget_set_buffer (gtk_sink->widget, buf);

   return GST_FLOW_OK;
 }
	/*
	* GStreamer
	* Copyright (C) 2015 Matthew Waters <matthew@centricular.com>
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Library General Public
	* License as published by the Free Software Foundation; either
	* version 2 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Library General Public License for more details.
	*
	* You should have received a copy of the GNU Library General Public
	* License along with this library; if not, write to the
	* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
	* Boston, MA 02110-1301, USA.
	*/

	/**
	* SECTION:gtkgstsink
	*
	*/

	#ifdef HAVE_CONFIG_H
	#include "config.h"
	#endif

	#include "gstgtksink.h"

	GST_DEBUG_CATEGORY (gst_debug_gtk_sink);
	#define GST_CAT_DEFAULT gst_debug_gtk_sink

	static void gst_gtk_sink_finalize (GObject * object);
	static void gst_gtk_sink_set_property (GObject * object, guint prop_id,
	const GValue * value, GParamSpec * param_spec);
	static void gst_gtk_sink_get_property (GObject * object, guint prop_id,
	GValue * value, GParamSpec * param_spec);

	static gboolean gst_gtk_sink_stop (GstBaseSink * bsink);

	static gboolean gst_gtk_sink_query (GstBaseSink * bsink, GstQuery * query);

	static GstStateChangeReturn
	gst_gtk_sink_change_state (GstElement * element, GstStateChange transition);

	static void gst_gtk_sink_get_times (GstBaseSink * bsink, GstBuffer * buf,
	GstClockTime * start, GstClockTime * end);
	static gboolean gst_gtk_sink_set_caps (GstBaseSink * bsink, GstCaps * caps);
	static GstFlowReturn gst_gtk_sink_show_frame (GstVideoSink * bsink,
	GstBuffer * buf);

	#if G_BYTE_ORDER == G_LITTLE_ENDIAN
	#define FORMATS "{ BGRx, BGRA }"
	#else
	#define FORMATS "{ xRGB, ARGB }"
	#endif

	static GstStaticPadTemplate gst_gtk_sink_template =
	GST_STATIC_PAD_TEMPLATE ("sink",
	GST_PAD_SINK,
	GST_PAD_ALWAYS,
	GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE (FORMATS))
	);

	#define DEFAULT_FORCE_ASPECT_RATIO TRUE
	#define DEFAULT_PAR_N 0
	#define DEFAULT_PAR_D 1
	#define DEFAULT_IGNORE_ALPHA TRUE

	enum
	{
	PROP_0,
	PROP_WIDGET,
	PROP_FORCE_ASPECT_RATIO,
	PROP_PIXEL_ASPECT_RATIO,
	PROP_IGNORE_ALPHA,
	};

	enum
	{
	SIGNAL_0,
	LAST_SIGNAL
	};

	#define gst_gtk_sink_parent_class parent_class
	G_DEFINE_TYPE_WITH_CODE (GstGtkSink, gst_gtk_sink,
	GST_TYPE_VIDEO_SINK, GST_DEBUG_CATEGORY_INIT (gst_debug_gtk_sink, "gtksink",
	0, "Gtk Video Sink"));

	static void
	gst_gtk_sink_class_init (GstGtkSinkClass * klass)
	{
	GObjectClass *gobject_class;
	GstElementClass *gstelement_class;
	GstBaseSinkClass *gstbasesink_class;
	GstVideoSinkClass *gstvideosink_class;

	gobject_class = (GObjectClass *) klass;
	gstelement_class = (GstElementClass *) klass;
	gstbasesink_class = (GstBaseSinkClass *) klass;
	gstvideosink_class = (GstVideoSinkClass *) klass;

	gobject_class->set_property = gst_gtk_sink_set_property;
	gobject_class->get_property = gst_gtk_sink_get_property;

	gst_element_class_set_metadata (gstelement_class, "Gtk Video Sink",
	"Sink/Video", "A video sink that renders to a GtkWidget",
	"Matthew Waters <matthew@centricular.com>");

	g_object_class_install_property (gobject_class, PROP_WIDGET,
	g_param_spec_object ("widget", "Gtk Widget",
	"The GtkWidget to place in the widget heirachy",
	GTK_TYPE_WIDGET, G_PARAM_READABLE \| G_PARAM_STATIC_STRINGS));

	g_object_class_install_property (gobject_class, PROP_FORCE_ASPECT_RATIO,
	g_param_spec_boolean ("force-aspect-ratio",
	"Force aspect ratio",
	"When enabled, scaling will respect original aspect ratio",
	DEFAULT_FORCE_ASPECT_RATIO,
	G_PARAM_READWRITE \| G_PARAM_STATIC_STRINGS));

	g_object_class_install_property (gobject_class, PROP_PIXEL_ASPECT_RATIO,
	gst_param_spec_fraction ("pixel-aspect-ratio", "Pixel Aspect Ratio",
	"The pixel aspect ratio of the device", DEFAULT_PAR_N, DEFAULT_PAR_D,
	G_MAXINT, 1, 1, 1, G_PARAM_READWRITE \| G_PARAM_STATIC_STRINGS));

	g_object_class_install_property (gobject_class, PROP_IGNORE_ALPHA,
	g_param_spec_boolean ("ignore-alpha", "Ignore Alpha",
	"When enabled, alpha will be ignored and converted to black",
	DEFAULT_IGNORE_ALPHA, G_PARAM_READWRITE \| G_PARAM_STATIC_STRINGS));

	gst_element_class_add_pad_template (gstelement_class,
	gst_static_pad_template_get (&gst_gtk_sink_template));

	gobject_class->finalize = gst_gtk_sink_finalize;

	gstelement_class->change_state = gst_gtk_sink_change_state;
	gstbasesink_class->query = gst_gtk_sink_query;
	gstbasesink_class->set_caps = gst_gtk_sink_set_caps;
	gstbasesink_class->get_times = gst_gtk_sink_get_times;
	gstbasesink_class->stop = gst_gtk_sink_stop;

	gstvideosink_class->show_frame = gst_gtk_sink_show_frame;
	}

	static void
	gst_gtk_sink_init (GstGtkSink * gtk_sink)
	{
	gtk_sink->force_aspect_ratio = DEFAULT_FORCE_ASPECT_RATIO;
	gtk_sink->par_n = DEFAULT_PAR_N;
	gtk_sink->par_d = DEFAULT_PAR_D;
	gtk_sink->ignore_alpha = DEFAULT_IGNORE_ALPHA;
	}

	static void
	gst_gtk_sink_finalize (GObject * object)
	{
	GstGtkSink *gtk_sink = GST_GTK_SINK (object);;

	g_object_unref (gtk_sink->widget);

	G_OBJECT_CLASS (parent_class)->finalize (object);
	}

	static GtkGstWidget *
	gst_gtk_sink_get_widget (GstGtkSink * gtk_sink)
	{
	if (gtk_sink->widget != NULL)
	return gtk_sink->widget;

	/* Ensure GTK is initialized, this has no side effect if it was already
	* initialized. Also, we do that lazily, so the application can be first */
	if (!gtk_init_check (NULL, NULL)) {
	GST_ERROR_OBJECT (gtk_sink, "Could not ensure GTK initialization.");
	return NULL;
	}

	gtk_sink->widget = (GtkGstWidget *) gtk_gst_widget_new ();
	gtk_sink->bind_aspect_ratio =
	g_object_bind_property (gtk_sink, "force-aspect-ratio", gtk_sink->widget,
	"force-aspect-ratio", G_BINDING_BIDIRECTIONAL \| G_BINDING_SYNC_CREATE);
	gtk_sink->bind_pixel_aspect_ratio =
	g_object_bind_property (gtk_sink, "pixel-aspect-ratio", gtk_sink->widget,
	"pixel-aspect-ratio", G_BINDING_BIDIRECTIONAL \| G_BINDING_SYNC_CREATE);
	gtk_sink->bind_ignore_alpha =
	g_object_bind_property (gtk_sink, "ignore-alpha", gtk_sink->widget,
	"ignore-alpha", G_BINDING_BIDIRECTIONAL \| G_BINDING_SYNC_CREATE);

	/* Take the floating ref, other wise the destruction of the container will
	* make this widget disapear possibly before we are done. */
	gst_object_ref_sink (gtk_sink->widget);

	return gtk_sink->widget;
	}

	static void
	gst_gtk_sink_get_property (GObject * object, guint prop_id,
	GValue * value, GParamSpec * pspec)
	{
	GstGtkSink *gtk_sink = GST_GTK_SINK (object);

	switch (prop_id) {
	case PROP_WIDGET:
	g_value_set_object (value, gst_gtk_sink_get_widget (gtk_sink));
	break;
	case PROP_FORCE_ASPECT_RATIO:
	g_value_set_boolean (value, gtk_sink->force_aspect_ratio);
	break;
	case PROP_PIXEL_ASPECT_RATIO:
	gst_value_set_fraction (value, gtk_sink->par_n, gtk_sink->par_d);
	break;
	case PROP_IGNORE_ALPHA:
	g_value_set_boolean (value, gtk_sink->ignore_alpha);
	break;
	default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
	break;
	}
	}

	static void
	gst_gtk_sink_set_property (GObject * object, guint prop_id,
	const GValue * value, GParamSpec * pspec)
	{
	GstGtkSink *gtk_sink = GST_GTK_SINK (object);

	switch (prop_id) {
	case PROP_FORCE_ASPECT_RATIO:
	gtk_sink->force_aspect_ratio = g_value_get_boolean (value);
	break;
	case PROP_PIXEL_ASPECT_RATIO:
	gtk_sink->par_n = gst_value_get_fraction_numerator (value);
	gtk_sink->par_d = gst_value_get_fraction_denominator (value);
	break;
	case PROP_IGNORE_ALPHA:
	gtk_sink->ignore_alpha = g_value_get_boolean (value);
	break;
	default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
	break;
	}
	}

	static gboolean
	gst_gtk_sink_query (GstBaseSink * bsink, GstQuery * query)
	{
	gboolean res = FALSE;

	switch (GST_QUERY_TYPE (query)) {
	default:
	res = GST_BASE_SINK_CLASS (parent_class)->query (bsink, query);
	break;
	}

	return res;
	}

	static gboolean
	gst_gtk_sink_stop (GstBaseSink * bsink)
	{
	return TRUE;
	}

	static GstStateChangeReturn
	gst_gtk_sink_change_state (GstElement * element, GstStateChange transition)
	{
	GstGtkSink *gtk_sink = GST_GTK_SINK (element);
	GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;

	GST_DEBUG ("changing state: %s => %s",
	gst_element_state_get_name (GST_STATE_TRANSITION_CURRENT (transition)),
	gst_element_state_get_name (GST_STATE_TRANSITION_NEXT (transition)));

	switch (transition) {
	case GST_STATE_CHANGE_NULL_TO_READY:
	if (gst_gtk_sink_get_widget (gtk_sink) == NULL)
	return GST_STATE_CHANGE_FAILURE;
	break;
	case GST_STATE_CHANGE_READY_TO_PAUSED:
	break;
	case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
	break;
	default:
	break;
	}

	ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
	if (ret == GST_STATE_CHANGE_FAILURE)
	return ret;

	switch (transition) {
	case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
	break;
	case GST_STATE_CHANGE_PAUSED_TO_READY:
	gtk_gst_widget_set_buffer (gtk_sink->widget, NULL);
	break;
	case GST_STATE_CHANGE_READY_TO_NULL:
	break;
	default:
	break;
	}

	return ret;
	}

	static void
	gst_gtk_sink_get_times (GstBaseSink * bsink, GstBuffer * buf,
	GstClockTime * start, GstClockTime * end)
	{
	GstGtkSink *gtk_sink;

	gtk_sink = GST_GTK_SINK (bsink);

	if (GST_BUFFER_TIMESTAMP_IS_VALID (buf)) {
	*start = GST_BUFFER_TIMESTAMP (buf);
	if (GST_BUFFER_DURATION_IS_VALID (buf))
	end = start + GST_BUFFER_DURATION (buf);
	else {
	if (GST_VIDEO_INFO_FPS_N (&gtk_sink->v_info) > 0) {
	end = start +
	gst_util_uint64_scale_int (GST_SECOND,
	GST_VIDEO_INFO_FPS_D (&gtk_sink->v_info),
	GST_VIDEO_INFO_FPS_N (&gtk_sink->v_info));
	}
	}
	}
	}

	gboolean
	gst_gtk_sink_set_caps (GstBaseSink * bsink, GstCaps * caps)
	{
	GstGtkSink *gtk_sink = GST_GTK_SINK (bsink);

	GST_DEBUG ("set caps with %" GST_PTR_FORMAT, caps);

	if (!gst_video_info_from_caps (&gtk_sink->v_info, caps))
	return FALSE;

	if (!gtk_gst_widget_set_caps (gtk_sink->widget, caps))
	return FALSE;

	return TRUE;
	}

	static GstFlowReturn
	gst_gtk_sink_show_frame (GstVideoSink * vsink, GstBuffer * buf)
	{
	GstGtkSink *gtk_sink;

	GST_TRACE ("rendering buffer:%p", buf);

	gtk_sink = GST_GTK_SINK (vsink);

	if (gtk_sink->widget)
	gtk_gst_widget_set_buffer (gtk_sink->widget, buf);

	return GST_FLOW_OK;
	}