Source/WebCore/platform/graphics/gstreamer/VideoSinkGStreamer.cpp - WebKit - Git at Google

 /*
  *  Copyright (C) 2007 OpenedHand
  *  Copyright (C) 2007 Alp Toker <alp@atoker.com>
  *  Copyright (C) 2009, 2010, 2011, 2012, 2015, 2016 Igalia S.L
  *  Copyright (C) 2015, 2016 Metrological Group B.V.
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser 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
  *  Lesser General Public License for more details.
  *
  *  You should have received a copy of the GNU Lesser General Public
  *  License along with this library; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */

 /*
  *
  * WebKitVideoSink is a GStreamer sink element that triggers
  * repaints in the WebKit GStreamer media player for the
  * current video buffer.
  */

 #include "config.h"
 #include "VideoSinkGStreamer.h"

 #if ENABLE(VIDEO) && USE(GSTREAMER)
 #include "GStreamerCommon.h"
 #include "IntSize.h"
 #include <glib.h>
 #include <gst/gst.h>
 #include <gst/video/gstvideometa.h>
 #include <wtf/Condition.h>
 #include <wtf/RunLoop.h>
 #include <wtf/glib/WTFGType.h>

 using namespace WebCore;

 // CAIRO_FORMAT_RGB24 used to render the video buffers is little/big endian dependant.
 #if G_BYTE_ORDER == G_LITTLE_ENDIAN
 #define GST_CAPS_FORMAT "{ BGRx, BGRA }"
 #else
 #define GST_CAPS_FORMAT "{ xRGB, ARGB }"
 #endif

 #define WEBKIT_VIDEO_SINK_PAD_CAPS GST_VIDEO_CAPS_MAKE_WITH_FEATURES(GST_CAPS_FEATURE_META_GST_VIDEO_GL_TEXTURE_UPLOAD_META, GST_CAPS_FORMAT) ";" GST_VIDEO_CAPS_MAKE(GST_CAPS_FORMAT)

 static GstStaticPadTemplate s_sinkTemplate = GST_STATIC_PAD_TEMPLATE("sink", GST_PAD_SINK, GST_PAD_ALWAYS, GST_STATIC_CAPS(WEBKIT_VIDEO_SINK_PAD_CAPS));


 GST_DEBUG_CATEGORY_STATIC(webkitVideoSinkDebug);
 #define GST_CAT_DEFAULT webkitVideoSinkDebug

 enum {
     REPAINT_REQUESTED,
     REPAINT_CANCELLED,
     LAST_SIGNAL
 };

 static guint webkitVideoSinkSignals[LAST_SIGNAL] = { 0, };

 static void webkitVideoSinkRepaintRequested(WebKitVideoSink*, GstSample*);
 static GRefPtr<GstSample> webkitVideoSinkRequestRender(WebKitVideoSink*, GstBuffer*);

 class VideoRenderRequestScheduler {
 public:
     void start()
     {
         Locker locker { m_sampleLock };
         m_unlocked = false;
     }

     void stop()
     {
         Locker locker { m_sampleLock };
         m_sample = nullptr;
         m_unlocked = true;
     }

     void drain()
     {
         Locker locker { m_sampleLock };
         m_sample = nullptr;
     }

     bool requestRender(WebKitVideoSink* sink, GstBuffer* buffer)
     {
         GRefPtr<GstSample> sample;
         {
             Locker locker { m_sampleLock };
             if (m_unlocked)
                 return true;

             m_sample = webkitVideoSinkRequestRender(sink, buffer);
             if (!m_sample)
                 return false;

             sample = std::exchange(m_sample, nullptr);
         }

         if (LIKELY(GST_IS_SAMPLE(sample.get())))
             webkitVideoSinkRepaintRequested(sink, sample.get());

         return true;
     }

 private:
     Lock m_sampleLock;
     GRefPtr<GstSample> m_sample WTF_GUARDED_BY_LOCK(m_sampleLock);

     // If this is true all processing should finish ASAP
     // This is necessary because there could be a race between
     // unlock() and render(), where unlock() wins, signals the
     // Condition, then render() tries to render a frame although
     // everything else isn't running anymore. This will lead
     // to deadlocks because render() holds the stream lock.
     //
     // Protected by the sample mutex
     bool m_unlocked { false };
 };

 struct _WebKitVideoSinkPrivate {
     _WebKitVideoSinkPrivate()
     {
         gst_video_info_init(&info);
     }

     ~_WebKitVideoSinkPrivate()
     {
         if (currentCaps)
             gst_caps_unref(currentCaps);
     }

     VideoRenderRequestScheduler scheduler;
     GstVideoInfo info;
     GstCaps* currentCaps { nullptr };
 };

 #define webkit_video_sink_parent_class parent_class
 WEBKIT_DEFINE_TYPE_WITH_CODE(WebKitVideoSink, webkit_video_sink, GST_TYPE_VIDEO_SINK, GST_DEBUG_CATEGORY_INIT(webkitVideoSinkDebug, "webkitsink", 0, "webkit video sink"))

 static void webkitVideoSinkConstructed(GObject* object)
 {
     g_object_set(GST_BASE_SINK(object), "enable-last-sample", FALSE, nullptr);
 }

 static void webkitVideoSinkRepaintRequested(WebKitVideoSink* sink, GstSample* sample)
 {
     g_signal_emit(sink, webkitVideoSinkSignals[REPAINT_REQUESTED], 0, sample);
 }

 static void webkitVideoSinkRepaintCancelled(WebKitVideoSink* sink)
 {
     g_signal_emit(sink, webkitVideoSinkSignals[REPAINT_CANCELLED], 0);
 }

 static GRefPtr<GstSample> webkitVideoSinkRequestRender(WebKitVideoSink* sink, GstBuffer* buffer)
 {
     WebKitVideoSinkPrivate* priv = sink->priv;
     GRefPtr<GstSample> sample = adoptGRef(gst_sample_new(buffer, priv->currentCaps, nullptr, nullptr));

     // The video info structure is valid only if the sink handled an allocation query.
     GstVideoFormat format = GST_VIDEO_INFO_FORMAT(&priv->info);
     if (format == GST_VIDEO_FORMAT_UNKNOWN)
         return nullptr;

     return sample;
 }

 static GstFlowReturn webkitVideoSinkRender(GstBaseSink* baseSink, GstBuffer* buffer)
 {
     WebKitVideoSink* sink = WEBKIT_VIDEO_SINK(baseSink);
     return sink->priv->scheduler.requestRender(sink, buffer) ? GST_FLOW_OK : GST_FLOW_ERROR;
 }

 static gboolean webkitVideoSinkUnlock(GstBaseSink* baseSink)
 {
     WebKitVideoSinkPrivate* priv = WEBKIT_VIDEO_SINK(baseSink)->priv;

     priv->scheduler.stop();
     webkitVideoSinkRepaintCancelled(WEBKIT_VIDEO_SINK(baseSink));

     return GST_CALL_PARENT_WITH_DEFAULT(GST_BASE_SINK_CLASS, unlock, (baseSink), TRUE);
 }

 static gboolean webkitVideoSinkUnlockStop(GstBaseSink* baseSink)
 {
     WebKitVideoSinkPrivate* priv = WEBKIT_VIDEO_SINK(baseSink)->priv;

     priv->scheduler.start();

     return GST_CALL_PARENT_WITH_DEFAULT(GST_BASE_SINK_CLASS, unlock_stop, (baseSink), TRUE);
 }

 static gboolean webkitVideoSinkStop(GstBaseSink* baseSink)
 {
     WebKitVideoSinkPrivate* priv = WEBKIT_VIDEO_SINK(baseSink)->priv;

     priv->scheduler.stop();
     webkitVideoSinkRepaintCancelled(WEBKIT_VIDEO_SINK(baseSink));
     if (priv->currentCaps) {
         gst_caps_unref(priv->currentCaps);
         priv->currentCaps = nullptr;
     }

     return TRUE;
 }

 static gboolean webkitVideoSinkStart(GstBaseSink* baseSink)
 {
     WebKitVideoSinkPrivate* priv = WEBKIT_VIDEO_SINK(baseSink)->priv;

     priv->scheduler.start();

     return TRUE;
 }

 static gboolean webkitVideoSinkSetCaps(GstBaseSink* baseSink, GstCaps* caps)
 {
     WebKitVideoSink* sink = WEBKIT_VIDEO_SINK(baseSink);
     WebKitVideoSinkPrivate* priv = sink->priv;

     GST_DEBUG_OBJECT(sink, "Current caps %" GST_PTR_FORMAT ", setting caps %" GST_PTR_FORMAT, priv->currentCaps, caps);

     GstVideoInfo videoInfo;
     gst_video_info_init(&videoInfo);
     if (!gst_video_info_from_caps(&videoInfo, caps)) {
         GST_ERROR_OBJECT(sink, "Invalid caps %" GST_PTR_FORMAT, caps);
         return FALSE;
     }

     priv->info = videoInfo;
     gst_caps_replace(&priv->currentCaps, caps);
     return TRUE;
 }

 static gboolean webkitVideoSinkProposeAllocation(GstBaseSink* baseSink, GstQuery* query)
 {
     GstCaps* caps;
     gst_query_parse_allocation(query, &caps, nullptr);
     if (!caps)
         return FALSE;

     WebKitVideoSink* sink = WEBKIT_VIDEO_SINK(baseSink);
     if (!gst_video_info_from_caps(&sink->priv->info, caps))
         return FALSE;

     gst_query_add_allocation_meta(query, GST_VIDEO_META_API_TYPE, nullptr);
     gst_query_add_allocation_meta(query, GST_VIDEO_CROP_META_API_TYPE, nullptr);
     gst_query_add_allocation_meta(query, GST_VIDEO_GL_TEXTURE_UPLOAD_META_API_TYPE, nullptr);
     return TRUE;
 }

 static gboolean webkitVideoSinkEvent(GstBaseSink* baseSink, GstEvent* event)
 {
     switch (GST_EVENT_TYPE(event)) {
     case GST_EVENT_FLUSH_START: {
         WebKitVideoSink* sink = WEBKIT_VIDEO_SINK(baseSink);
         sink->priv->scheduler.drain();

         GST_DEBUG_OBJECT(sink, "Flush-start, releasing m_sample");
         }
         FALLTHROUGH;
     default:
         return GST_CALL_PARENT_WITH_DEFAULT(GST_BASE_SINK_CLASS, event, (baseSink, event), TRUE);
     }
 }

 static void webkit_video_sink_class_init(WebKitVideoSinkClass* klass)
 {
     GObjectClass* gobjectClass = G_OBJECT_CLASS(klass);
     GstBaseSinkClass* baseSinkClass = GST_BASE_SINK_CLASS(klass);
     GstElementClass* elementClass = GST_ELEMENT_CLASS(klass);

     gst_element_class_add_pad_template(elementClass, gst_static_pad_template_get(&s_sinkTemplate));
     gst_element_class_set_metadata(elementClass, "WebKit video sink", "Sink/Video", "Sends video data from a GStreamer pipeline to WebKit", "Igalia, Alp Toker <alp@atoker.com>");

     gobjectClass->constructed = webkitVideoSinkConstructed;

     baseSinkClass->unlock = webkitVideoSinkUnlock;
     baseSinkClass->unlock_stop = webkitVideoSinkUnlockStop;
     baseSinkClass->render = webkitVideoSinkRender;
     baseSinkClass->preroll = webkitVideoSinkRender;
     baseSinkClass->stop = webkitVideoSinkStop;
     baseSinkClass->start = webkitVideoSinkStart;
     baseSinkClass->set_caps = webkitVideoSinkSetCaps;
     baseSinkClass->propose_allocation = webkitVideoSinkProposeAllocation;
     baseSinkClass->event = webkitVideoSinkEvent;

     webkitVideoSinkSignals[REPAINT_REQUESTED] = g_signal_new("repaint-requested",
             G_TYPE_FROM_CLASS(klass),
             static_cast<GSignalFlags>(G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION),
             0, // Class offset
             0, // Accumulator
             0, // Accumulator data
             g_cclosure_marshal_generic,
             G_TYPE_NONE, // Return type
             1, // Only one parameter
             GST_TYPE_SAMPLE);
     webkitVideoSinkSignals[REPAINT_CANCELLED] = g_signal_new("repaint-cancelled",
         G_TYPE_FROM_CLASS(klass),
         G_SIGNAL_RUN_LAST,
         0, // Class offset
         nullptr, // Accumulator
         nullptr, // Accumulator data
         g_cclosure_marshal_generic,
         G_TYPE_NONE, // Return type
         0, // No parameters
         G_TYPE_NONE);
 }


 GstElement* webkitVideoSinkNew()
 {
     return GST_ELEMENT(g_object_new(WEBKIT_TYPE_VIDEO_SINK, nullptr));
 }

 #endif // ENABLE(VIDEO) && USE(GSTREAMER)
	/*
	* Copyright (C) 2007 OpenedHand
	* Copyright (C) 2007 Alp Toker <alp@atoker.com>
	* Copyright (C) 2009, 2010, 2011, 2012, 2015, 2016 Igalia S.L
	* Copyright (C) 2015, 2016 Metrological Group B.V.
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser 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
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this library; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	*/

	/*
	*
	* WebKitVideoSink is a GStreamer sink element that triggers
	* repaints in the WebKit GStreamer media player for the
	* current video buffer.
	*/

	#include "config.h"
	#include "VideoSinkGStreamer.h"

	#if ENABLE(VIDEO) && USE(GSTREAMER)
	#include "GStreamerCommon.h"
	#include "IntSize.h"
	#include <glib.h>
	#include <gst/gst.h>
	#include <gst/video/gstvideometa.h>
	#include <wtf/Condition.h>
	#include <wtf/RunLoop.h>
	#include <wtf/glib/WTFGType.h>

	using namespace WebCore;

	// CAIRO_FORMAT_RGB24 used to render the video buffers is little/big endian dependant.
	#if G_BYTE_ORDER == G_LITTLE_ENDIAN
	#define GST_CAPS_FORMAT "{ BGRx, BGRA }"
	#else
	#define GST_CAPS_FORMAT "{ xRGB, ARGB }"
	#endif

	#define WEBKIT_VIDEO_SINK_PAD_CAPS GST_VIDEO_CAPS_MAKE_WITH_FEATURES(GST_CAPS_FEATURE_META_GST_VIDEO_GL_TEXTURE_UPLOAD_META, GST_CAPS_FORMAT) ";" GST_VIDEO_CAPS_MAKE(GST_CAPS_FORMAT)

	static GstStaticPadTemplate s_sinkTemplate = GST_STATIC_PAD_TEMPLATE("sink", GST_PAD_SINK, GST_PAD_ALWAYS, GST_STATIC_CAPS(WEBKIT_VIDEO_SINK_PAD_CAPS));


	GST_DEBUG_CATEGORY_STATIC(webkitVideoSinkDebug);
	#define GST_CAT_DEFAULT webkitVideoSinkDebug

	enum {
	REPAINT_REQUESTED,
	REPAINT_CANCELLED,
	LAST_SIGNAL
	};

	static guint webkitVideoSinkSignals[LAST_SIGNAL] = { 0, };

	static void webkitVideoSinkRepaintRequested(WebKitVideoSink, GstSample);
	static GRefPtr<GstSample> webkitVideoSinkRequestRender(WebKitVideoSink, GstBuffer);

	class VideoRenderRequestScheduler {
	public:
	void start()
	{
	Locker locker { m_sampleLock };
	m_unlocked = false;
	}

	void stop()
	{
	Locker locker { m_sampleLock };
	m_sample = nullptr;
	m_unlocked = true;
	}

	void drain()
	{
	Locker locker { m_sampleLock };
	m_sample = nullptr;
	}

	bool requestRender(WebKitVideoSink* sink, GstBuffer* buffer)
	{
	GRefPtr<GstSample> sample;
	{
	Locker locker { m_sampleLock };
	if (m_unlocked)
	return true;

	m_sample = webkitVideoSinkRequestRender(sink, buffer);
	if (!m_sample)
	return false;

	sample = std::exchange(m_sample, nullptr);
	}

	if (LIKELY(GST_IS_SAMPLE(sample.get())))
	webkitVideoSinkRepaintRequested(sink, sample.get());

	return true;
	}

	private:
	Lock m_sampleLock;
	GRefPtr<GstSample> m_sample WTF_GUARDED_BY_LOCK(m_sampleLock);

	// If this is true all processing should finish ASAP
	// This is necessary because there could be a race between
	// unlock() and render(), where unlock() wins, signals the
	// Condition, then render() tries to render a frame although
	// everything else isn't running anymore. This will lead
	// to deadlocks because render() holds the stream lock.
	//
	// Protected by the sample mutex
	bool m_unlocked { false };
	};

	struct _WebKitVideoSinkPrivate {
	_WebKitVideoSinkPrivate()
	{
	gst_video_info_init(&info);
	}

	~_WebKitVideoSinkPrivate()
	{
	if (currentCaps)
	gst_caps_unref(currentCaps);
	}

	VideoRenderRequestScheduler scheduler;
	GstVideoInfo info;
	GstCaps* currentCaps { nullptr };
	};

	#define webkit_video_sink_parent_class parent_class
	WEBKIT_DEFINE_TYPE_WITH_CODE(WebKitVideoSink, webkit_video_sink, GST_TYPE_VIDEO_SINK, GST_DEBUG_CATEGORY_INIT(webkitVideoSinkDebug, "webkitsink", 0, "webkit video sink"))

	static void webkitVideoSinkConstructed(GObject* object)
	{
	g_object_set(GST_BASE_SINK(object), "enable-last-sample", FALSE, nullptr);
	}

	static void webkitVideoSinkRepaintRequested(WebKitVideoSink* sink, GstSample* sample)
	{
	g_signal_emit(sink, webkitVideoSinkSignals[REPAINT_REQUESTED], 0, sample);
	}

	static void webkitVideoSinkRepaintCancelled(WebKitVideoSink* sink)
	{
	g_signal_emit(sink, webkitVideoSinkSignals[REPAINT_CANCELLED], 0);
	}

	static GRefPtr<GstSample> webkitVideoSinkRequestRender(WebKitVideoSink* sink, GstBuffer* buffer)
	{
	WebKitVideoSinkPrivate* priv = sink->priv;
	GRefPtr<GstSample> sample = adoptGRef(gst_sample_new(buffer, priv->currentCaps, nullptr, nullptr));

	// The video info structure is valid only if the sink handled an allocation query.
	GstVideoFormat format = GST_VIDEO_INFO_FORMAT(&priv->info);
	if (format == GST_VIDEO_FORMAT_UNKNOWN)
	return nullptr;

	return sample;
	}

	static GstFlowReturn webkitVideoSinkRender(GstBaseSink* baseSink, GstBuffer* buffer)
	{
	WebKitVideoSink* sink = WEBKIT_VIDEO_SINK(baseSink);
	return sink->priv->scheduler.requestRender(sink, buffer) ? GST_FLOW_OK : GST_FLOW_ERROR;
	}

	static gboolean webkitVideoSinkUnlock(GstBaseSink* baseSink)
	{
	WebKitVideoSinkPrivate* priv = WEBKIT_VIDEO_SINK(baseSink)->priv;

	priv->scheduler.stop();
	webkitVideoSinkRepaintCancelled(WEBKIT_VIDEO_SINK(baseSink));

	return GST_CALL_PARENT_WITH_DEFAULT(GST_BASE_SINK_CLASS, unlock, (baseSink), TRUE);
	}

	static gboolean webkitVideoSinkUnlockStop(GstBaseSink* baseSink)
	{
	WebKitVideoSinkPrivate* priv = WEBKIT_VIDEO_SINK(baseSink)->priv;

	priv->scheduler.start();

	return GST_CALL_PARENT_WITH_DEFAULT(GST_BASE_SINK_CLASS, unlock_stop, (baseSink), TRUE);
	}

	static gboolean webkitVideoSinkStop(GstBaseSink* baseSink)
	{
	WebKitVideoSinkPrivate* priv = WEBKIT_VIDEO_SINK(baseSink)->priv;

	priv->scheduler.stop();
	webkitVideoSinkRepaintCancelled(WEBKIT_VIDEO_SINK(baseSink));
	if (priv->currentCaps) {
	gst_caps_unref(priv->currentCaps);
	priv->currentCaps = nullptr;
	}

	return TRUE;
	}

	static gboolean webkitVideoSinkStart(GstBaseSink* baseSink)
	{
	WebKitVideoSinkPrivate* priv = WEBKIT_VIDEO_SINK(baseSink)->priv;

	priv->scheduler.start();

	return TRUE;
	}

	static gboolean webkitVideoSinkSetCaps(GstBaseSink* baseSink, GstCaps* caps)
	{
	WebKitVideoSink* sink = WEBKIT_VIDEO_SINK(baseSink);
	WebKitVideoSinkPrivate* priv = sink->priv;

	GST_DEBUG_OBJECT(sink, "Current caps %" GST_PTR_FORMAT ", setting caps %" GST_PTR_FORMAT, priv->currentCaps, caps);

	GstVideoInfo videoInfo;
	gst_video_info_init(&videoInfo);
	if (!gst_video_info_from_caps(&videoInfo, caps)) {
	GST_ERROR_OBJECT(sink, "Invalid caps %" GST_PTR_FORMAT, caps);
	return FALSE;
	}

	priv->info = videoInfo;
	gst_caps_replace(&priv->currentCaps, caps);
	return TRUE;
	}

	static gboolean webkitVideoSinkProposeAllocation(GstBaseSink* baseSink, GstQuery* query)
	{
	GstCaps* caps;
	gst_query_parse_allocation(query, &caps, nullptr);
	if (!caps)
	return FALSE;

	WebKitVideoSink* sink = WEBKIT_VIDEO_SINK(baseSink);
	if (!gst_video_info_from_caps(&sink->priv->info, caps))
	return FALSE;

	gst_query_add_allocation_meta(query, GST_VIDEO_META_API_TYPE, nullptr);
	gst_query_add_allocation_meta(query, GST_VIDEO_CROP_META_API_TYPE, nullptr);
	gst_query_add_allocation_meta(query, GST_VIDEO_GL_TEXTURE_UPLOAD_META_API_TYPE, nullptr);
	return TRUE;
	}

	static gboolean webkitVideoSinkEvent(GstBaseSink* baseSink, GstEvent* event)
	{
	switch (GST_EVENT_TYPE(event)) {
	case GST_EVENT_FLUSH_START: {
	WebKitVideoSink* sink = WEBKIT_VIDEO_SINK(baseSink);
	sink->priv->scheduler.drain();

	GST_DEBUG_OBJECT(sink, "Flush-start, releasing m_sample");
	}
	FALLTHROUGH;
	default:
	return GST_CALL_PARENT_WITH_DEFAULT(GST_BASE_SINK_CLASS, event, (baseSink, event), TRUE);
	}
	}

	static void webkit_video_sink_class_init(WebKitVideoSinkClass* klass)
	{
	GObjectClass* gobjectClass = G_OBJECT_CLASS(klass);
	GstBaseSinkClass* baseSinkClass = GST_BASE_SINK_CLASS(klass);
	GstElementClass* elementClass = GST_ELEMENT_CLASS(klass);

	gst_element_class_add_pad_template(elementClass, gst_static_pad_template_get(&s_sinkTemplate));
	gst_element_class_set_metadata(elementClass, "WebKit video sink", "Sink/Video", "Sends video data from a GStreamer pipeline to WebKit", "Igalia, Alp Toker <alp@atoker.com>");

	gobjectClass->constructed = webkitVideoSinkConstructed;

	baseSinkClass->unlock = webkitVideoSinkUnlock;
	baseSinkClass->unlock_stop = webkitVideoSinkUnlockStop;
	baseSinkClass->render = webkitVideoSinkRender;
	baseSinkClass->preroll = webkitVideoSinkRender;
	baseSinkClass->stop = webkitVideoSinkStop;
	baseSinkClass->start = webkitVideoSinkStart;
	baseSinkClass->set_caps = webkitVideoSinkSetCaps;
	baseSinkClass->propose_allocation = webkitVideoSinkProposeAllocation;
	baseSinkClass->event = webkitVideoSinkEvent;

	webkitVideoSinkSignals[REPAINT_REQUESTED] = g_signal_new("repaint-requested",
	G_TYPE_FROM_CLASS(klass),
	static_cast<GSignalFlags>(G_SIGNAL_RUN_LAST \| G_SIGNAL_ACTION),
	0, // Class offset
	0, // Accumulator
	0, // Accumulator data
	g_cclosure_marshal_generic,
	G_TYPE_NONE, // Return type
	1, // Only one parameter
	GST_TYPE_SAMPLE);
	webkitVideoSinkSignals[REPAINT_CANCELLED] = g_signal_new("repaint-cancelled",
	G_TYPE_FROM_CLASS(klass),
	G_SIGNAL_RUN_LAST,
	0, // Class offset
	nullptr, // Accumulator
	nullptr, // Accumulator data
	g_cclosure_marshal_generic,
	G_TYPE_NONE, // Return type
	0, // No parameters
	G_TYPE_NONE);
	}


	GstElement* webkitVideoSinkNew()
	{
	return GST_ELEMENT(g_object_new(WEBKIT_TYPE_VIDEO_SINK, nullptr));
	}

	#endif // ENABLE(VIDEO) && USE(GSTREAMER)