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 Q_SLOTS:

    void onFinalFrameReceived(PlaybackEngineObjectID sourceID);

    void render(Frame);

Q_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