VideoSinkGStreamer.cpp

/*
 *  Copyright (C) 2007 OpenedHand
 *  Copyright (C) 2007 Alp Toker <alp@atoker.com>
 *  Copyright (C) 2009, 2010, 2011, 2012 Igalia S.L
 *
 *  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 "GRefPtrGStreamer.h"
#include "GStreamerUtilities.h"
#include "IntSize.h"
#include <glib.h>
#include <gst/gst.h>
#include <gst/video/gstvideometa.h>
#include <wtf/OwnPtr.h>
#include <wtf/gobject/GMainLoopSource.h>
#include <wtf/gobject/GMutexLocker.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
#if GST_CHECK_VERSION(1, 1, 0)
#define GST_FEATURED_CAPS GST_VIDEO_CAPS_MAKE_WITH_FEATURES(GST_CAPS_FEATURE_META_GST_VIDEO_GL_TEXTURE_UPLOAD_META, GST_CAPS_FORMAT) ";"
#else
#define GST_FEATURED_CAPS
#endif

#define WEBKIT_VIDEO_SINK_PAD_CAPS GST_FEATURED_CAPS 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,
    LAST_SIGNAL
};

enum {
    PROP_0,
    PROP_CAPS
};

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

struct _WebKitVideoSinkPrivate {
    GstBuffer* buffer;
    GMainLoopSource timeoutSource;
    GMutex* bufferMutex;
    GCond* dataCondition;

    GstVideoInfo info;

    GstCaps* currentCaps;

    // 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
    // GCond, 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 buffer mutex
    bool unlocked;
};

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


static void webkit_video_sink_init(WebKitVideoSink* sink)
{
    sink->priv = G_TYPE_INSTANCE_GET_PRIVATE(sink, WEBKIT_TYPE_VIDEO_SINK, WebKitVideoSinkPrivate);
    new (sink->priv) WebKitVideoSinkPrivate();
#if GLIB_CHECK_VERSION(2, 31, 0)
    sink->priv->dataCondition = new GCond;
    g_cond_init(sink->priv->dataCondition);
    sink->priv->bufferMutex = new GMutex;
    g_mutex_init(sink->priv->bufferMutex);
#else
    sink->priv->dataCondition = g_cond_new();
    sink->priv->bufferMutex = g_mutex_new();
#endif

    gst_video_info_init(&sink->priv->info);
}

static void webkitVideoSinkTimeoutCallback(WebKitVideoSink* sink)
{
    WebKitVideoSinkPrivate* priv = sink->priv;

    GMutexLocker lock(priv->bufferMutex);
    GstBuffer* buffer = priv->buffer;
    priv->buffer = 0;

    if (!buffer || priv->unlocked || UNLIKELY(!GST_IS_BUFFER(buffer))) {
        g_cond_signal(priv->dataCondition);
        return;
    }

    g_signal_emit(sink, webkitVideoSinkSignals[REPAINT_REQUESTED], 0, buffer);
    gst_buffer_unref(buffer);
    g_cond_signal(priv->dataCondition);
}

static GstFlowReturn webkitVideoSinkRender(GstBaseSink* baseSink, GstBuffer* buffer)
{
    WebKitVideoSink* sink = WEBKIT_VIDEO_SINK(baseSink);
    WebKitVideoSinkPrivate* priv = sink->priv;

    GMutexLocker lock(priv->bufferMutex);

    if (priv->unlocked)
        return GST_FLOW_OK;

    priv->buffer = gst_buffer_ref(buffer);

    GRefPtr<GstCaps> caps;
    // The video info structure is valid only if the sink handled an allocation query.
    if (GST_VIDEO_INFO_FORMAT(&priv->info) != GST_VIDEO_FORMAT_UNKNOWN)
        caps = adoptGRef(gst_video_info_to_caps(&priv->info));
    else
        caps = priv->currentCaps;

    GstVideoFormat format;
    WebCore::IntSize size;
    int pixelAspectRatioNumerator, pixelAspectRatioDenominator, stride;
    if (!getVideoSizeAndFormatFromCaps(caps.get(), size, format, pixelAspectRatioNumerator, pixelAspectRatioDenominator, stride)) {
        gst_buffer_unref(buffer);
        return GST_FLOW_ERROR;
    }

    // Cairo's ARGB has pre-multiplied alpha while GStreamer's doesn't.
    // Here we convert to Cairo's ARGB.
    if (format == GST_VIDEO_FORMAT_ARGB || format == GST_VIDEO_FORMAT_BGRA) {
        // Because GstBaseSink::render() only owns the buffer reference in the
        // method scope we can't use gst_buffer_make_writable() here. Also
        // The buffer content should not be changed here because the same buffer
        // could be passed multiple times to this method (in theory).

        GstBuffer* newBuffer = WebCore::createGstBuffer(buffer);

        // Check if allocation failed.
        if (UNLIKELY(!newBuffer))
            return GST_FLOW_ERROR;

        // We don't use Color::premultipliedARGBFromColor() here because
        // one function call per video pixel is just too expensive:
        // For 720p/PAL for example this means 1280*720*25=23040000
        // function calls per second!
        GstMapInfo sourceInfo;
        GstMapInfo destinationInfo;
        gst_buffer_map(buffer, &sourceInfo, GST_MAP_READ);
        const guint8* source = const_cast<guint8*>(sourceInfo.data);
        gst_buffer_map(newBuffer, &destinationInfo, GST_MAP_WRITE);
        guint8* destination = static_cast<guint8*>(destinationInfo.data);

        for (int x = 0; x < size.height(); x++) {
            for (int y = 0; y < size.width(); y++) {
#if G_BYTE_ORDER == G_LITTLE_ENDIAN
                unsigned short alpha = source[3];
                destination[0] = (source[0] * alpha + 128) / 255;
                destination[1] = (source[1] * alpha + 128) / 255;
                destination[2] = (source[2] * alpha + 128) / 255;
                destination[3] = alpha;
#else
                unsigned short alpha = source[0];
                destination[0] = alpha;
                destination[1] = (source[1] * alpha + 128) / 255;
                destination[2] = (source[2] * alpha + 128) / 255;
                destination[3] = (source[3] * alpha + 128) / 255;
#endif
                source += 4;
                destination += 4;
            }
        }

        gst_buffer_unmap(buffer, &sourceInfo);
        gst_buffer_unmap(newBuffer, &destinationInfo);
        gst_buffer_unref(buffer);
        buffer = priv->buffer = newBuffer;
    }

    // This should likely use a lower priority, but glib currently starves
    // lower priority sources.
    // See: https://bugzilla.gnome.org/show_bug.cgi?id=610830.
    gst_object_ref(sink);
    priv->timeoutSource.schedule("[WebKit] webkitVideoSinkTimeoutCallback", std::function<void()>(std::bind(webkitVideoSinkTimeoutCallback, sink)), G_PRIORITY_DEFAULT,
        [sink] { gst_object_unref(sink); });

    g_cond_wait(priv->dataCondition, priv->bufferMutex);
    return GST_FLOW_OK;
}

static void webkitVideoSinkDispose(GObject* object)
{
    WebKitVideoSink* sink = WEBKIT_VIDEO_SINK(object);
    WebKitVideoSinkPrivate* priv = sink->priv;

    if (priv->dataCondition) {
#if GLIB_CHECK_VERSION(2, 31, 0)
        g_cond_clear(priv->dataCondition);
        delete priv->dataCondition;
#else
        g_cond_free(priv->dataCondition);
#endif
        priv->dataCondition = 0;
    }

    if (priv->bufferMutex) {
#if GLIB_CHECK_VERSION(2, 31, 0)
        g_mutex_clear(priv->bufferMutex);
        delete priv->bufferMutex;
#else
        g_mutex_free(priv->bufferMutex);
#endif
        priv->bufferMutex = 0;
    }

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

static void webkitVideoSinkFinalize(GObject* object)
{
    WEBKIT_VIDEO_SINK(object)->priv->~WebKitVideoSinkPrivate();
    G_OBJECT_CLASS(parent_class)->finalize(object);
}

static void webkitVideoSinkGetProperty(GObject* object, guint propertyId, GValue* value, GParamSpec* parameterSpec)
{
    WebKitVideoSink* sink = WEBKIT_VIDEO_SINK(object);
    WebKitVideoSinkPrivate* priv = sink->priv;

    switch (propertyId) {
    case PROP_CAPS: {
        GstCaps* caps = priv->currentCaps;
        if (caps)
            gst_caps_ref(caps);
        g_value_take_boxed(value, caps);
        break;
    }
    default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID(object, propertyId, parameterSpec);
    }
}

static void unlockBufferMutex(WebKitVideoSinkPrivate* priv)
{
    GMutexLocker lock(priv->bufferMutex);

    if (priv->buffer) {
        gst_buffer_unref(priv->buffer);
        priv->buffer = 0;
    }

    priv->unlocked = true;

    g_cond_signal(priv->dataCondition);
}

static gboolean webkitVideoSinkUnlock(GstBaseSink* baseSink)
{
    WebKitVideoSink* sink = WEBKIT_VIDEO_SINK(baseSink);

    unlockBufferMutex(sink->priv);

    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;

    {
        GMutexLocker lock(priv->bufferMutex);
        priv->unlocked = false;
    }

    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;

    unlockBufferMutex(priv);

    if (priv->currentCaps) {
        gst_caps_unref(priv->currentCaps);
        priv->currentCaps = 0;
    }

    return TRUE;
}

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

    GMutexLocker lock(priv->bufferMutex);
    priv->unlocked = false;
    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 info;
    if (!gst_video_info_from_caps(&info, caps)) {
        GST_ERROR_OBJECT(sink, "Invalid caps %" GST_PTR_FORMAT, caps);
        return FALSE;
    }

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

static gboolean webkitVideoSinkProposeAllocation(GstBaseSink* baseSink, GstQuery* query)
{
    GstCaps* caps;
    gst_query_parse_allocation(query, &caps, 0);
    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, 0);
    gst_query_add_allocation_meta(query, GST_VIDEO_CROP_META_API_TYPE, 0);
#if GST_CHECK_VERSION(1, 1, 0)
    gst_query_add_allocation_meta(query, GST_VIDEO_GL_TEXTURE_UPLOAD_META_API_TYPE, 0);
#endif
    return 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>");

    g_type_class_add_private(klass, sizeof(WebKitVideoSinkPrivate));

    gobjectClass->dispose = webkitVideoSinkDispose;
    gobjectClass->finalize = webkitVideoSinkFinalize;
    gobjectClass->get_property = webkitVideoSinkGetProperty;

    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;

    g_object_class_install_property(gobjectClass, PROP_CAPS,
        g_param_spec_boxed("current-caps", "Current-Caps", "Current caps", GST_TYPE_CAPS, G_PARAM_READABLE));

    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_BUFFER);
}


GstElement* webkitVideoSinkNew()
{
    return GST_ELEMENT(g_object_new(WEBKIT_TYPE_VIDEO_SINK, 0));
}

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