Moved general gstreamer helper classes into separate library.

Cleaned up configuration of gstreamer with a separate config
test.

Change-Id: I1ec9ee466233687fbcfdc544a12d9fce578e4379
Reviewed-on: http://codereview.qt-project.org/6459
Sanity-Review: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Michael Goddard <michael.goddard@nokia.com>

1 files changed, 791 insertions, 0 deletions

diff --git a/src/gsttools/qvideosurfacegstsink.cpp b/src/gsttools/qvideosurfacegstsink.cpp
new file mode 100644
index 000000000..3df1401d2
--- /dev/null
+++ b/src/gsttools/qvideosurfacegstsink.cpp
@@ -0,0 +1,791 @@
+/****************************************************************************
+**
+** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <qabstractvideosurface.h>
+#include <qvideoframe.h>
+#include <QDebug>
+#include <QMap>
+#include <QDebug>
+#include <QThread>
+
+#include "qgstvideobuffer_p.h"
+
+#if defined(Q_WS_X11) && !defined(QT_NO_XVIDEO)
+#include <QtWidgets/qx11info_x11.h>
+#include "qgstxvimagebuffer_p.h"
+#endif
+
+#include "qvideosurfacegstsink_p.h"
+
+//#define DEBUG_VIDEO_SURFACE_SINK
+
+
+Q_DECLARE_METATYPE(QVideoSurfaceFormat)
+
+QVideoSurfaceGstDelegate::QVideoSurfaceGstDelegate(
+    QAbstractVideoSurface *surface)
+    : m_surface(surface)
+    , m_pool(0)
+    , m_renderReturn(GST_FLOW_ERROR)
+    , m_bytesPerLine(0)
+    , m_startCanceled(false)
+{
+    if (m_surface) {
+#if defined(Q_WS_X11) && !defined(QT_NO_XVIDEO)
+        m_pools.append(new QGstXvImageBufferPool());
+#endif
+        updateSupportedFormats();
+        connect(m_surface, SIGNAL(supportedFormatsChanged()), this, SLOT(updateSupportedFormats()));
+    }
+}
+
+QVideoSurfaceGstDelegate::~QVideoSurfaceGstDelegate()
+{
+    qDeleteAll(m_pools);
+}
+
+QList<QVideoFrame::PixelFormat> QVideoSurfaceGstDelegate::supportedPixelFormats(QAbstractVideoBuffer::HandleType handleType) const
+{
+    QMutexLocker locker(const_cast<QMutex *>(&m_mutex));
+
+    if (!m_surface)
+        return QList<QVideoFrame::PixelFormat>();
+    else if (handleType == QAbstractVideoBuffer::NoHandle)
+        return m_supportedPixelFormats;
+    else if (handleType == m_pool->handleType())
+        return m_supportedPoolPixelFormats;
+    else
+        return m_surface->supportedPixelFormats(handleType);
+}
+
+QVideoSurfaceFormat QVideoSurfaceGstDelegate::surfaceFormat() const
+{
+    QMutexLocker locker(const_cast<QMutex *>(&m_mutex));
+    return m_format;
+}
+
+bool QVideoSurfaceGstDelegate::start(const QVideoSurfaceFormat &format, int bytesPerLine)
+{
+    if (!m_surface)
+        return false;
+
+    QMutexLocker locker(&m_mutex);
+
+    m_format = format;
+    m_bytesPerLine = bytesPerLine;
+
+    if (QThread::currentThread() == thread()) {
+        m_started = !m_surface.isNull() ? m_surface->start(m_format) : false;
+    } else {
+        m_started = false;
+        m_startCanceled = false;
+        QMetaObject::invokeMethod(this, "queuedStart", Qt::QueuedConnection);
+
+        /*
+        Waiting for start() to be invoked in the main thread may block
+        if gstreamer blocks the main thread until this call is finished.
+        This situation is rare and usually caused by setState(Null)
+        while pipeline is being prerolled.
+
+        The proper solution to this involves controlling gstreamer pipeline from
+        other thread than video surface.
+
+        Currently start() fails if wait() timed out.
+        */
+        if (!m_setupCondition.wait(&m_mutex, 1000)) {
+            qWarning() << "Failed to start video surface due to main thread blocked.";
+            m_startCanceled = true;
+        }
+    }
+
+    m_format = m_surface->surfaceFormat();
+
+    return m_started;
+}
+
+void QVideoSurfaceGstDelegate::stop()
+{
+    if (!m_surface)
+        return;
+
+    QMutexLocker locker(&m_mutex);
+
+    if (QThread::currentThread() == thread()) {
+        if (!m_surface.isNull())
+            m_surface->stop();
+    } else {
+        QMetaObject::invokeMethod(this, "queuedStop", Qt::QueuedConnection);
+
+        // Waiting for stop() to be invoked in the main thread may block
+        // if gstreamer blocks the main thread until this call is finished.
+        m_setupCondition.wait(&m_mutex, 500);
+    }
+
+    m_started = false;
+}
+
+bool QVideoSurfaceGstDelegate::isActive()
+{
+    QMutexLocker locker(&m_mutex);
+    return !m_surface.isNull() && m_surface->isActive();
+}
+
+GstFlowReturn QVideoSurfaceGstDelegate::render(GstBuffer *buffer)
+{
+    if (!m_surface) {
+        qWarning() << "Rendering video frame to deleted surface, skip.";
+        //return GST_FLOW_NOT_NEGOTIATED;
+        return GST_FLOW_OK;
+    }
+
+    QMutexLocker locker(&m_mutex);
+
+    QAbstractVideoBuffer *videoBuffer = 0;
+
+    if (m_pool && G_TYPE_CHECK_INSTANCE_TYPE(buffer, m_pool->bufferType()))
+        videoBuffer = m_pool->prepareVideoBuffer(buffer, m_bytesPerLine);
+    else
+        videoBuffer = new QGstVideoBuffer(buffer, m_bytesPerLine);
+
+    m_frame = QVideoFrame(
+            videoBuffer,
+            m_format.frameSize(),
+            m_format.pixelFormat());
+
+    qint64 startTime = GST_BUFFER_TIMESTAMP(buffer);
+
+    if (startTime >= 0) {
+        m_frame.setStartTime(startTime/G_GINT64_CONSTANT (1000000));
+
+        qint64 duration = GST_BUFFER_DURATION(buffer);
+
+        if (duration >= 0)
+            m_frame.setEndTime((startTime + duration)/G_GINT64_CONSTANT (1000000));
+    }
+
+    QMetaObject::invokeMethod(this, "queuedRender", Qt::QueuedConnection);
+
+    if (!m_renderCondition.wait(&m_mutex, 300)) {
+        m_frame = QVideoFrame();
+
+        return GST_FLOW_OK;
+    } else {
+        return m_renderReturn;
+    }
+}
+
+void QVideoSurfaceGstDelegate::queuedStart()
+{
+    if (!m_startCanceled) {
+        QMutexLocker locker(&m_mutex);
+        m_started = m_surface->start(m_format);
+        m_setupCondition.wakeAll();
+    }
+}
+
+void QVideoSurfaceGstDelegate::queuedStop()
+{
+    QMutexLocker locker(&m_mutex);
+
+    m_surface->stop();
+
+    m_setupCondition.wakeAll();
+}
+
+void QVideoSurfaceGstDelegate::queuedRender()
+{
+    QMutexLocker locker(&m_mutex);
+
+    if (m_surface.isNull()) {
+        qWarning() << "Rendering video frame to deleted surface, skip the frame";
+        m_renderReturn = GST_FLOW_OK;
+    } else if (m_surface->present(m_frame)) {
+        m_renderReturn = GST_FLOW_OK;
+    } else {
+        switch (m_surface->error()) {
+        case QAbstractVideoSurface::NoError:
+            m_renderReturn = GST_FLOW_OK;
+            break;
+        case QAbstractVideoSurface::StoppedError:
+            //It's likely we are in process of changing video output
+            //and the surface is already stopped, ignore the frame
+            m_renderReturn = GST_FLOW_OK;
+            break;
+        default:
+            qWarning() << "Failed to render video frame:" << m_surface->error();
+            m_renderReturn = GST_FLOW_OK;
+            break;
+        }
+    }
+
+    m_renderCondition.wakeAll();
+}
+
+void QVideoSurfaceGstDelegate::updateSupportedFormats()
+{
+    QAbstractGstBufferPool *newPool = 0;
+    foreach (QAbstractGstBufferPool *pool, m_pools) {
+        if (!m_surface->supportedPixelFormats(pool->handleType()).isEmpty()) {
+            newPool = pool;
+            break;
+        }
+    }
+
+    if (newPool != m_pool) {
+        QMutexLocker lock(&m_poolMutex);
+
+        if (m_pool)
+            m_pool->clear();
+        m_pool = newPool;
+    }
+
+    QMutexLocker locker(&m_mutex);
+
+    m_supportedPixelFormats.clear();
+    m_supportedPoolPixelFormats.clear();
+    if (m_surface) {
+        m_supportedPixelFormats = m_surface->supportedPixelFormats();
+        if (m_pool)
+            m_supportedPoolPixelFormats = m_surface->supportedPixelFormats(m_pool->handleType());
+    }
+}
+
+struct YuvFormat
+{
+    QVideoFrame::PixelFormat pixelFormat;
+    guint32 fourcc;
+    int bitsPerPixel;
+};
+
+static const YuvFormat qt_yuvColorLookup[] =
+{
+    { QVideoFrame::Format_YUV420P, GST_MAKE_FOURCC('I','4','2','0'), 8 },
+    { QVideoFrame::Format_YV12,    GST_MAKE_FOURCC('Y','V','1','2'), 8 },
+    { QVideoFrame::Format_UYVY,    GST_MAKE_FOURCC('U','Y','V','Y'), 16 },
+    { QVideoFrame::Format_YUYV,    GST_MAKE_FOURCC('Y','U','Y','2'), 16 },
+    { QVideoFrame::Format_NV12,    GST_MAKE_FOURCC('N','V','1','2'), 8 },
+    { QVideoFrame::Format_NV21,    GST_MAKE_FOURCC('N','V','2','1'), 8 },
+    { QVideoFrame::Format_AYUV444, GST_MAKE_FOURCC('A','Y','U','V'), 32 }
+};
+
+static int indexOfYuvColor(QVideoFrame::PixelFormat format)
+{
+    const int count = sizeof(qt_yuvColorLookup) / sizeof(YuvFormat);
+
+    for (int i = 0; i < count; ++i)
+        if (qt_yuvColorLookup[i].pixelFormat == format)
+            return i;
+
+    return -1;
+}
+
+static int indexOfYuvColor(guint32 fourcc)
+{
+    const int count = sizeof(qt_yuvColorLookup) / sizeof(YuvFormat);
+
+    for (int i = 0; i < count; ++i)
+        if (qt_yuvColorLookup[i].fourcc == fourcc)
+            return i;
+
+    return -1;
+}
+
+struct RgbFormat
+{
+    QVideoFrame::PixelFormat pixelFormat;
+    int bitsPerPixel;
+    int depth;
+    int endianness;
+    int red;
+    int green;
+    int blue;
+    int alpha;
+};
+
+static const RgbFormat qt_rgbColorLookup[] =
+{
+    { QVideoFrame::Format_RGB32 , 32, 24, 4321, 0x0000FF00, 0x00FF0000, 0xFF000000, 0x00000000 },
+    { QVideoFrame::Format_RGB32 , 32, 24, 1234, 0x00FF0000, 0x0000FF00, 0x000000FF, 0x00000000 },
+    { QVideoFrame::Format_BGR32 , 32, 24, 4321, 0xFF000000, 0x00FF0000, 0x0000FF00, 0x00000000 },
+    { QVideoFrame::Format_BGR32 , 32, 24, 1234, 0x000000FF, 0x0000FF00, 0x00FF0000, 0x00000000 },
+    { QVideoFrame::Format_ARGB32, 32, 24, 4321, 0x0000FF00, 0x00FF0000, 0xFF000000, 0x000000FF },
+    { QVideoFrame::Format_ARGB32, 32, 24, 1234, 0x00FF0000, 0x0000FF00, 0x000000FF, 0xFF000000 },
+    { QVideoFrame::Format_RGB24 , 24, 24, 4321, 0x00FF0000, 0x0000FF00, 0x000000FF, 0x00000000 },
+    { QVideoFrame::Format_BGR24 , 24, 24, 4321, 0x000000FF, 0x0000FF00, 0x00FF0000, 0x00000000 },
+    { QVideoFrame::Format_RGB565, 16, 16, 1234, 0x0000F800, 0x000007E0, 0x0000001F, 0x00000000 }
+};
+
+static int indexOfRgbColor(
+        int bits, int depth, int endianness, int red, int green, int blue, int alpha)
+{
+    const int count = sizeof(qt_rgbColorLookup) / sizeof(RgbFormat);
+
+    for (int i = 0; i < count; ++i) {
+        if (qt_rgbColorLookup[i].bitsPerPixel == bits
+            && qt_rgbColorLookup[i].depth == depth
+            && qt_rgbColorLookup[i].endianness == endianness
+            && qt_rgbColorLookup[i].red == red
+            && qt_rgbColorLookup[i].green == green
+            && qt_rgbColorLookup[i].blue == blue
+            && qt_rgbColorLookup[i].alpha == alpha) {
+            return i;
+        }
+    }
+    return -1;
+}
+
+static GstVideoSinkClass *sink_parent_class;
+
+#define VO_SINK(s) QVideoSurfaceGstSink *sink(reinterpret_cast<QVideoSurfaceGstSink *>(s))
+
+QVideoSurfaceGstSink *QVideoSurfaceGstSink::createSink(QAbstractVideoSurface *surface)
+{
+    QVideoSurfaceGstSink *sink = reinterpret_cast<QVideoSurfaceGstSink *>(
+            g_object_new(QVideoSurfaceGstSink::get_type(), 0));
+
+    sink->delegate = new QVideoSurfaceGstDelegate(surface);
+
+    return sink;
+}
+
+GType QVideoSurfaceGstSink::get_type()
+{
+    static GType type = 0;
+
+    if (type == 0) {
+        static const GTypeInfo info =
+        {
+            sizeof(QVideoSurfaceGstSinkClass),                    // class_size
+            base_init,                                         // base_init
+            NULL,                                              // base_finalize
+            class_init,                                        // class_init
+            NULL,                                              // class_finalize
+            NULL,                                              // class_data
+            sizeof(QVideoSurfaceGstSink),                         // instance_size
+            0,                                                 // n_preallocs
+            instance_init,                                     // instance_init
+            0                                                  // value_table
+        };
+
+        type = g_type_register_static(
+                GST_TYPE_VIDEO_SINK, "QVideoSurfaceGstSink", &info, GTypeFlags(0));
+    }
+
+    return type;
+}
+
+void QVideoSurfaceGstSink::class_init(gpointer g_class, gpointer class_data)
+{
+    Q_UNUSED(class_data);
+
+    sink_parent_class = reinterpret_cast<GstVideoSinkClass *>(g_type_class_peek_parent(g_class));
+
+    GstBaseSinkClass *base_sink_class = reinterpret_cast<GstBaseSinkClass *>(g_class);
+    base_sink_class->get_caps = QVideoSurfaceGstSink::get_caps;
+    base_sink_class->set_caps = QVideoSurfaceGstSink::set_caps;
+    base_sink_class->buffer_alloc = QVideoSurfaceGstSink::buffer_alloc;
+    base_sink_class->start = QVideoSurfaceGstSink::start;
+    base_sink_class->stop = QVideoSurfaceGstSink::stop;
+    // base_sink_class->unlock = QVideoSurfaceGstSink::unlock; // Not implemented.
+    // base_sink_class->event = QVideoSurfaceGstSink::event; // Not implemented.
+    base_sink_class->preroll = QVideoSurfaceGstSink::preroll;
+    base_sink_class->render = QVideoSurfaceGstSink::render;
+
+    GstElementClass *element_class = reinterpret_cast<GstElementClass *>(g_class);
+    element_class->change_state = QVideoSurfaceGstSink::change_state;
+
+    GObjectClass *object_class = reinterpret_cast<GObjectClass *>(g_class);
+    object_class->finalize = QVideoSurfaceGstSink::finalize;
+}
+
+void QVideoSurfaceGstSink::base_init(gpointer g_class)
+{
+    static GstStaticPadTemplate sink_pad_template = GST_STATIC_PAD_TEMPLATE(
+            "sink", GST_PAD_SINK, GST_PAD_ALWAYS, GST_STATIC_CAPS(
+                    "video/x-raw-rgb, "
+                    "framerate = (fraction) [ 0, MAX ], "
+                    "width = (int) [ 1, MAX ], "
+                    "height = (int) [ 1, MAX ]; "
+                    "video/x-raw-yuv, "
+                    "framerate = (fraction) [ 0, MAX ], "
+                    "width = (int) [ 1, MAX ], "
+                    "height = (int) [ 1, MAX ]"));
+
+    gst_element_class_add_pad_template(
+            GST_ELEMENT_CLASS(g_class), gst_static_pad_template_get(&sink_pad_template));
+}
+
+void QVideoSurfaceGstSink::instance_init(GTypeInstance *instance, gpointer g_class)
+{
+    VO_SINK(instance);
+
+    Q_UNUSED(g_class);
+
+    sink->delegate = 0;
+
+    sink->lastRequestedCaps = 0;
+    sink->lastBufferCaps = 0;
+    sink->lastSurfaceFormat = new QVideoSurfaceFormat;
+}
+
+void QVideoSurfaceGstSink::finalize(GObject *object)
+{
+    VO_SINK(object);
+
+    delete sink->lastSurfaceFormat;
+    sink->lastSurfaceFormat = 0;
+
+    if (sink->lastBufferCaps)
+        gst_caps_unref(sink->lastBufferCaps);
+    sink->lastBufferCaps = 0;
+
+    if (sink->lastRequestedCaps)
+        gst_caps_unref(sink->lastRequestedCaps);
+    sink->lastRequestedCaps = 0;
+}
+
+GstStateChangeReturn QVideoSurfaceGstSink::change_state(
+        GstElement *element, GstStateChange transition)
+{
+    Q_UNUSED(element);
+
+    return GST_ELEMENT_CLASS(sink_parent_class)->change_state(
+            element, transition);
+}
+
+GstCaps *QVideoSurfaceGstSink::get_caps(GstBaseSink *base)
+{
+    VO_SINK(base);
+
+    GstCaps *caps = gst_caps_new_empty();
+
+    foreach (QVideoFrame::PixelFormat format, sink->delegate->supportedPixelFormats()) {
+        int index = indexOfYuvColor(format);
+
+        if (index != -1) {
+            gst_caps_append_structure(caps, gst_structure_new(
+                    "video/x-raw-yuv",
+                    "framerate", GST_TYPE_FRACTION_RANGE, 0, 1, INT_MAX, 1,
+                    "width"    , GST_TYPE_INT_RANGE, 1, INT_MAX,
+                    "height"   , GST_TYPE_INT_RANGE, 1, INT_MAX,
+                    "format"   , GST_TYPE_FOURCC, qt_yuvColorLookup[index].fourcc,
+                    NULL));
+            continue;
+        }
+
+        const int count = sizeof(qt_rgbColorLookup) / sizeof(RgbFormat);
+
+        for (int i = 0; i < count; ++i) {
+            if (qt_rgbColorLookup[i].pixelFormat == format) {
+                GstStructure *structure = gst_structure_new(
+                        "video/x-raw-rgb",
+                        "framerate" , GST_TYPE_FRACTION_RANGE, 0, 1, INT_MAX, 1,
+                        "width"     , GST_TYPE_INT_RANGE, 1, INT_MAX,
+                        "height"    , GST_TYPE_INT_RANGE, 1, INT_MAX,
+                        "bpp"       , G_TYPE_INT, qt_rgbColorLookup[i].bitsPerPixel,
+                        "depth"     , G_TYPE_INT, qt_rgbColorLookup[i].depth,
+                        "endianness", G_TYPE_INT, qt_rgbColorLookup[i].endianness,
+                        "red_mask"  , G_TYPE_INT, qt_rgbColorLookup[i].red,
+                        "green_mask", G_TYPE_INT, qt_rgbColorLookup[i].green,
+                        "blue_mask" , G_TYPE_INT, qt_rgbColorLookup[i].blue,
+                        NULL);
+
+                if (qt_rgbColorLookup[i].alpha != 0) {
+                    gst_structure_set(
+                            structure, "alpha_mask", G_TYPE_INT, qt_rgbColorLookup[i].alpha, NULL);
+                }
+                gst_caps_append_structure(caps, structure);
+            }
+        }
+    }
+
+    return caps;
+}
+
+gboolean QVideoSurfaceGstSink::set_caps(GstBaseSink *base, GstCaps *caps)
+{
+    VO_SINK(base);
+
+#ifdef DEBUG_VIDEO_SURFACE_SINK
+    qDebug() << "set_caps:";
+    qDebug() << gst_caps_to_string(caps);
+#endif
+
+    if (!caps) {
+        sink->delegate->stop();
+
+        return TRUE;
+    } else {
+        int bytesPerLine = 0;
+        QVideoSurfaceFormat format = formatForCaps(caps, &bytesPerLine);
+
+        if (sink->delegate->isActive()) {
+            QVideoSurfaceFormat surfaceFormst = sink->delegate->surfaceFormat();
+
+            if (format.pixelFormat() == surfaceFormst.pixelFormat() &&
+                format.frameSize() == surfaceFormst.frameSize())
+                return TRUE;
+            else
+                sink->delegate->stop();
+        }
+
+        if (sink->lastRequestedCaps)
+            gst_caps_unref(sink->lastRequestedCaps);
+        sink->lastRequestedCaps = 0;
+
+#ifdef DEBUG_VIDEO_SURFACE_SINK
+        qDebug() << "Staring video surface, format:";
+        qDebug() << format;
+        qDebug() << "bytesPerLine:" << bytesPerLine;
+#endif
+
+        if (sink->delegate->start(format, bytesPerLine))
+            return TRUE;
+        else
+            qWarning() << "Failed to start video surface";
+    }
+
+    return FALSE;
+}
+
+QVideoSurfaceFormat QVideoSurfaceGstSink::formatForCaps(GstCaps *caps, int *bytesPerLine)
+{
+    const GstStructure *structure = gst_caps_get_structure(caps, 0);
+
+    QVideoFrame::PixelFormat pixelFormat = QVideoFrame::Format_Invalid;
+    int bitsPerPixel = 0;
+
+    QSize size;
+    gst_structure_get_int(structure, "width", &size.rwidth());
+    gst_structure_get_int(structure, "height", &size.rheight());
+
+    if (qstrcmp(gst_structure_get_name(structure), "video/x-raw-yuv") == 0) {
+        guint32 fourcc = 0;
+        gst_structure_get_fourcc(structure, "format", &fourcc);
+
+        int index = indexOfYuvColor(fourcc);
+        if (index != -1) {
+            pixelFormat = qt_yuvColorLookup[index].pixelFormat;
+            bitsPerPixel = qt_yuvColorLookup[index].bitsPerPixel;
+        }
+    } else if (qstrcmp(gst_structure_get_name(structure), "video/x-raw-rgb") == 0) {
+        int depth = 0;
+        int endianness = 0;
+        int red = 0;
+        int green = 0;
+        int blue = 0;
+        int alpha = 0;
+
+        gst_structure_get_int(structure, "bpp", &bitsPerPixel);
+        gst_structure_get_int(structure, "depth", &depth);
+        gst_structure_get_int(structure, "endianness", &endianness);
+        gst_structure_get_int(structure, "red_mask", &red);
+        gst_structure_get_int(structure, "green_mask", &green);
+        gst_structure_get_int(structure, "blue_mask", &blue);
+        gst_structure_get_int(structure, "alpha_mask", &alpha);
+
+        int index = indexOfRgbColor(bitsPerPixel, depth, endianness, red, green, blue, alpha);
+
+        if (index != -1)
+            pixelFormat = qt_rgbColorLookup[index].pixelFormat;
+    }
+
+    if (pixelFormat != QVideoFrame::Format_Invalid) {
+        QVideoSurfaceFormat format(size, pixelFormat);
+
+        QPair<int, int> rate;
+        gst_structure_get_fraction(structure, "framerate", &rate.first, &rate.second);
+
+        if (rate.second)
+            format.setFrameRate(qreal(rate.first)/rate.second);
+
+        gint aspectNum = 0;
+        gint aspectDenum = 0;
+        if (gst_structure_get_fraction(
+                structure, "pixel-aspect-ratio", &aspectNum, &aspectDenum)) {
+            if (aspectDenum > 0)
+                format.setPixelAspectRatio(aspectNum, aspectDenum);
+        }
+
+        if (bytesPerLine)
+            *bytesPerLine = ((size.width() * bitsPerPixel / 8) + 3) & ~3;
+
+        return format;
+    }
+
+    return QVideoSurfaceFormat();
+}
+
+
+GstFlowReturn QVideoSurfaceGstSink::buffer_alloc(
+        GstBaseSink *base, guint64 offset, guint size, GstCaps *caps, GstBuffer **buffer)
+{
+    VO_SINK(base);
+
+    Q_UNUSED(offset);
+    Q_UNUSED(size);
+
+    if (!buffer)
+        return GST_FLOW_ERROR;
+
+    *buffer = NULL;
+
+    if (!sink->delegate->pool())
+        return GST_FLOW_OK;
+
+    QMutexLocker poolLock(sink->delegate->poolMutex());
+    QAbstractGstBufferPool *pool = sink->delegate->pool();
+
+    if (!pool)
+        return GST_FLOW_OK;
+
+    if (sink->lastRequestedCaps && gst_caps_is_equal(sink->lastRequestedCaps, caps)) {
+        //qDebug() << "reusing last caps";
+        *buffer = GST_BUFFER(pool->takeBuffer(*sink->lastSurfaceFormat, sink->lastBufferCaps));
+        return GST_FLOW_OK;
+    }
+
+    if (sink->delegate->supportedPixelFormats(pool->handleType()).isEmpty()) {
+        //qDebug() << "sink doesn't support native pool buffers, skip buffers allocation";
+        return GST_FLOW_OK;
+    }
+
+    GstCaps *intersection = gst_caps_intersect(get_caps(GST_BASE_SINK(sink)), caps);
+
+    if (gst_caps_is_empty (intersection)) {
+        gst_caps_unref(intersection);
+        return GST_FLOW_NOT_NEGOTIATED;
+    }
+
+    poolLock.unlock();
+
+    if (sink->delegate->isActive()) {
+        //if format was changed, restart the surface
+        QVideoSurfaceFormat format = formatForCaps(intersection);
+        QVideoSurfaceFormat surfaceFormat = sink->delegate->surfaceFormat();
+
+        if (format.pixelFormat() != surfaceFormat.pixelFormat() ||
+            format.frameSize() != surfaceFormat.frameSize()) {
+#ifdef DEBUG_VIDEO_SURFACE_SINK
+            qDebug() << "new format requested, restart video surface";
+#endif
+            sink->delegate->stop();
+        }
+    }
+
+    if (!sink->delegate->isActive()) {
+        int bytesPerLine = 0;
+        QVideoSurfaceFormat format = formatForCaps(intersection, &bytesPerLine);
+
+        if (!sink->delegate->start(format, bytesPerLine)) {
+            qWarning() << "failed to start video surface";
+            return GST_FLOW_NOT_NEGOTIATED;
+        }
+    }
+
+    poolLock.relock();
+    pool = sink->delegate->pool();
+
+    QVideoSurfaceFormat surfaceFormat = sink->delegate->surfaceFormat();
+
+    if (!pool->isFormatSupported(surfaceFormat)) {
+        //qDebug() << "sink doesn't support native pool format, skip custom buffers allocation";
+        return GST_FLOW_OK;
+    }
+
+    if (sink->lastRequestedCaps)
+        gst_caps_unref(sink->lastRequestedCaps);
+    sink->lastRequestedCaps = caps;
+    gst_caps_ref(sink->lastRequestedCaps);
+
+    if (sink->lastBufferCaps)
+        gst_caps_unref(sink->lastBufferCaps);
+    sink->lastBufferCaps = intersection;
+    gst_caps_ref(sink->lastBufferCaps);
+
+    *sink->lastSurfaceFormat = surfaceFormat;
+
+    *buffer =  GST_BUFFER(pool->takeBuffer(surfaceFormat, intersection));
+
+    return GST_FLOW_OK;
+}
+
+gboolean QVideoSurfaceGstSink::start(GstBaseSink *base)
+{
+    Q_UNUSED(base);
+
+    return TRUE;
+}
+
+gboolean QVideoSurfaceGstSink::stop(GstBaseSink *base)
+{
+    Q_UNUSED(base);
+
+    return TRUE;
+}
+
+gboolean QVideoSurfaceGstSink::unlock(GstBaseSink *base)
+{
+    Q_UNUSED(base);
+
+    return TRUE;
+}
+
+gboolean QVideoSurfaceGstSink::event(GstBaseSink *base, GstEvent *event)
+{
+    Q_UNUSED(base);
+    Q_UNUSED(event);
+
+    return TRUE;
+}
+
+GstFlowReturn QVideoSurfaceGstSink::preroll(GstBaseSink *base, GstBuffer *buffer)
+{
+    VO_SINK(base);
+    return sink->delegate->render(buffer);
+}
+
+GstFlowReturn QVideoSurfaceGstSink::render(GstBaseSink *base, GstBuffer *buffer)
+{
+    VO_SINK(base);
+    return sink->delegate->render(buffer);
+}
+