qffmpegrenderer_p.h

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// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#ifndef QFFMPEGRENDERER_P_H
#define QFFMPEGRENDERER_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 <QtFFmpegMediaPluginImpl/private/qffmpegplaybackengineobject_p.h>
#include <QtFFmpegMediaPluginImpl/private/qffmpegtimecontroller_p.h>
#include <QtFFmpegMediaPluginImpl/private/qffmpegframe_p.h>
 
#include <QtCore/qpointer.h>
#include <QtCore/qqueue.h>
 
#include <chrono>
 
QT_BEGIN_NAMESPACE
 
namespace QFFmpeg {
 
class Renderer : public PlaybackEngineObject
{
    Q_OBJECT
public:
    using TimePoint = SteadyClock::time_point;
 
    Renderer(const PlaybackEngineObjectID &id, const TimeController &tc);
 
    TrackPosition seekPosition() const;
 
    TrackPosition lastPosition() const;
 
    void setPlaybackRate(float rate);
 
    void doForceStep();
 
    bool isStepForced() const;
 
    void setTimeController(const TimeController &tc);
 
    void seek(quint64 sessionId, const TimeController &tc, const LoopOffset &offset);
 
public slots:
 
    void onFinalFrameReceived(PlaybackEngineObjectID sourceID);
 
    void render(Frame);
 
signals:
    void frameProcessed(Frame);
 
    void synchronized(PlaybackEngineObjectID id, TimePoint tp, TrackPosition pos);
 
    void forceStepDone();
 
    void loopChanged(PlaybackEngineObjectID id, TrackPosition offset, int index);
 
protected:
    bool setForceStepDone();
 
    void onPauseChanged() override;
 
    bool canDoNextStep() const override;
 
    TimePoint nextTimePoint() const override;
 
    virtual void seekInternal() { }
 
    virtual void onPlaybackRateChanged() { }
 
    struct RenderingResult
    {
        bool done = true;
        std::chrono::microseconds recheckInterval = std::chrono::microseconds(0);
    };
 
    virtual RenderingResult renderInternal(Frame frame) = 0;
 
    float playbackRate() const;
 
    std::chrono::microseconds frameDelay(const Frame &frame,
                                         TimePoint timePoint = SteadyClock::now()) const;
 
    void changeRendererTime(std::chrono::microseconds offset);
 
    template<typename Output, typename ChangeHandler>
    void setOutputInternal(QPointer<Output> &actual, Output *desired, ChangeHandler &&changeHandler)
    {
        const auto connectionType =
                thread()->isCurrentThread() ? Qt::AutoConnection : Qt::BlockingQueuedConnection;
        auto doer = [desired, changeHandler, &actual]() {
            const auto prev = std::exchange(actual, desired);
            if (prev != desired)
                changeHandler(prev);
        };
        QMetaObject::invokeMethod(this, doer, connectionType);
    }
 
private:
    void doNextStep() override;
 
private:
    struct SessionContext
    {
        TimeController timeController;
        int loopIndex = 0;
        TrackPosition lastFrameEnd = timeController.currentPosition();
        QAtomicInteger<qint64> lastPosition = lastFrameEnd.get();
        QAtomicInteger<qint64> seekPos = lastFrameEnd.get();
        QQueue<Frame> frames = {};
        std::optional<TimePoint> explicitNextFrameTime = {};
    };
 
    SessionContext m_sessionCtx;
    QAtomicInteger<bool> m_isStepForced = false;
};
 
} // namespace QFFmpeg
 
QT_END_NAMESPACE
 
#endif // QFFMPEGRENDERER_P_H