qffmpegtimecontroller_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 QFFMPEGTIMECONTROLLER_P_H
#define QFFMPEGTIMECONTROLLER_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 "qglobal.h"
 
#include <chrono>
#include <optional>
 
QT_BEGIN_NAMESPACE
 
namespace QFFmpeg {
 
class TimeController
{
    using TrackTime = std::chrono::microseconds;
 
public:
    using Clock = std::chrono::steady_clock;
    using TimePoint = Clock::time_point;
    using PlaybackRate = float;
 
    TimeController();
 
    float playbackRate() const;
 
    void setPlaybackRate(PlaybackRate playbackRate);
 
    void sync(qint64 trackPos = 0);
 
    void sync(const TimePoint &tp, qint64 pos);
 
    void syncSoft(const TimePoint &tp, qint64 pos,
                  const Clock::duration &fixingTime = std::chrono::seconds(4));
 
    qint64 currentPosition(const Clock::duration &offset = Clock::duration{ 0 }) const;
 
    void setPaused(bool paused);
 
    qint64 positionFromTime(TimePoint tp, bool ignorePause = false) const;
 
    TimePoint timeFromPosition(qint64 pos, bool ignorePause = false) const;
 
private:
    struct SoftSyncData
    {
        TimePoint srcTimePoint;
        TrackTime srcPosition;
        TimePoint dstTimePoint;
        TrackTime srcPosOffest;
        TrackTime dstPosition;
        PlaybackRate internalRate = 1;
    };
 
    SoftSyncData makeSoftSyncData(const TimePoint &srcTp, const TrackTime &srcPos,
                                  const TimePoint &dstTp) const;
 
    TrackTime positionFromTimeInternal(const TimePoint &tp) const;
 
    TimePoint timeFromPositionInternal(const TrackTime &pos) const;
 
    void scrollTimeTillNow();
 
    template<typename T>
    static Clock::duration toClockTime(const T &t);
 
    template<typename T>
    static TrackTime toTrackTime(const T &t);
 
private:
    bool m_paused = true;
    PlaybackRate m_playbackRate = 1;
    TrackTime m_position;
    TimePoint m_timePoint = {};
    std::optional<SoftSyncData> m_softSyncData;
};
 
} // namespace QFFmpeg
 
QT_END_NAMESPACE
 
#endif // QFFMPEGTIMECONTROLLER_P_H