qgstvideorenderersink_p.h

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// Copyright (C) 2016 Jolla Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#ifndef QGSTVIDEORENDERERSINK_P_H
#define QGSTVIDEORENDERERSINK_P_H
 
//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API. It exists purely as an
// implementation detail. This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//
 
#include <QtMultimedia/qvideoframeformat.h>
#include <QtMultimedia/qvideoframe.h>
#include <QtMultimedia/private/qtmultimediaglobal_p.h>
#include <QtCore/qcoreevent.h>
#include <QtCore/qlist.h>
#include <QtCore/qmutex.h>
#include <QtCore/qpointer.h>
#include <QtCore/qqueue.h>
#include <QtCore/qwaitcondition.h>
 
#include <gst/video/gstvideosink.h>
#include <gst/video/video.h>
 
#include <common/qgstvideobuffer_p.h>
#include <common/qgst_p.h>
 
QT_BEGIN_NAMESPACE
 
namespace QGstUtils {
 
template <typename T>
class QConcurrentQueue
{
public:
    qsizetype enqueue(T value)
    {
        QMutexLocker locker(&mutex);
        queue.append(std::move(value));
        return queue.size();
    }
 
    std::optional<T> dequeue()
    {
        QMutexLocker locker(&mutex);
        if (queue.isEmpty())
            return std::nullopt;
 
        return queue.takeFirst();
    }
 
    void clear()
    {
        QMutexLocker locker(&mutex);
        queue.clear();
    }
 
private:
    QMutex mutex;
    QList<T> queue;
};
 
} // namespace QGstUtils
 
class QGstVideoRenderer : public QObject
{
    struct RenderBufferState
    {
        QGstBufferHandle buffer;
        QVideoFrameFormat format;
        GstVideoInfo videoInfo;
        QGstCaps::MemoryFormat memoryFormat;
 
        bool operator==(const RenderBufferState &rhs) const
        {
            return std::tie(buffer, format, memoryFormat)
                    == std::tie(rhs.buffer, rhs.format, rhs.memoryFormat);
        }
    };
 
    static constexpr QEvent::Type renderFramesEvent = static_cast<QEvent::Type>(QEvent::User + 100);
    static constexpr QEvent::Type stopEvent = static_cast<QEvent::Type>(QEvent::User + 101);
 
public:
    explicit QGstVideoRenderer(QGstreamerVideoSink *);
    ~QGstVideoRenderer() override;
 
    const QGstCaps &caps();
 
    bool start(const QGstCaps &);
    void stop();
    void unlock();
    bool proposeAllocation(GstQuery *);
    GstFlowReturn render(GstBuffer *);
    bool query(GstQuery *);
    void gstEvent(GstEvent *);
 
    void setActive(bool);
 
private:
    void updateCurrentVideoFrame(QVideoFrame);
 
    void notify();
    static QGstCaps createSurfaceCaps(QGstreamerVideoSink *);
 
    void customEvent(QEvent *) override;
    void handleNewBuffer(RenderBufferState);
 
    void gstEventHandleTag(GstEvent *);
    void gstEventHandleEOS(GstEvent *);
    void gstEventHandleFlushStart(GstEvent *);
    void gstEventHandleFlushStop(GstEvent *);
 
    QMutex m_sinkMutex;
    QGstreamerVideoSink *m_sink = nullptr; // written only from qt thread. so only readers on
                                           // worker threads need to acquire the lock
 
    // --- only accessed from gstreamer thread
    const QGstCaps m_surfaceCaps;
    QVideoFrameFormat m_format;
    GstVideoInfo m_videoInfo{};
    QGstCaps::MemoryFormat m_capsMemoryFormat = QGstCaps::CpuMemory;
 
    // --- only accessed from qt thread
    QVideoFrame m_currentPipelineFrame;
    QVideoFrame m_currentVideoFrame;
    bool m_isActive{ false };
 
    QGstUtils::QConcurrentQueue<RenderBufferState> m_bufferQueue;
    bool m_flushing{ false };
};
 
class QGstVideoRendererSinkElement;
 
class QGstVideoRendererSink
{
public:
    GstVideoSink parent{};
 
    static QGstVideoRendererSinkElement createSink(QGstreamerVideoSink *surface);
 
private:
    static void setSink(QGstreamerVideoSink *surface);
 
    static GType get_type();
    static void class_init(gpointer g_class, gpointer class_data);
    static void base_init(gpointer g_class);
    static void instance_init(GTypeInstance *instance, gpointer g_class);
 
    static void finalize(GObject *object);
 
    static GstStateChangeReturn change_state(GstElement *element, GstStateChange transition);
 
    static GstCaps *get_caps(GstBaseSink *sink, GstCaps *filter);
    static gboolean set_caps(GstBaseSink *sink, GstCaps *caps);
 
    static gboolean propose_allocation(GstBaseSink *sink, GstQuery *query);
 
    static gboolean stop(GstBaseSink *sink);
 
    static gboolean unlock(GstBaseSink *sink);
 
    static GstFlowReturn show_frame(GstVideoSink *sink, GstBuffer *buffer);
    static gboolean query(GstBaseSink *element, GstQuery *query);
    static gboolean event(GstBaseSink *element, GstEvent *event);
 
    friend class QGstVideoRendererSinkElement;
 
    QGstVideoRenderer *renderer = nullptr;
};
 
class QGstVideoRendererSinkClass
{
public:
    GstVideoSinkClass parent_class;
};
 
class QGstVideoRendererSinkElement : public QGstBaseSink
{
public:
    using QGstBaseSink::QGstBaseSink;
 
    explicit QGstVideoRendererSinkElement(QGstVideoRendererSink *, RefMode);
 
    QGstVideoRendererSinkElement(const QGstVideoRendererSinkElement &) = default;
    QGstVideoRendererSinkElement(QGstVideoRendererSinkElement &&) noexcept = default;
    QGstVideoRendererSinkElement &operator=(const QGstVideoRendererSinkElement &) = default;
    QGstVideoRendererSinkElement &operator=(QGstVideoRendererSinkElement &&) noexcept = default;
 
    void setActive(bool);
 
    QGstVideoRendererSink *qGstVideoRendererSink() const;
};
 
QT_END_NAMESPACE
 
#endif