Revision control
++ // Copyright (C) 2026 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 QFFMPEGFRAMERATEADAPTER_P_H
++ #define QFFMPEGFRAMERATEADAPTER_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/qvideoframe.h>
++ #include <QtCore/qlist.h>
++ #include <QtFFmpegMediaPluginImpl/private/qffmpegrecordingengineutils_p.h>
++
++ #include <optional>
++
++ QT_BEGIN_NAMESPACE
++
++ namespace QFFmpeg {
++
++ // Adapts an incoming video stream to a target frame rate by dropping (source faster)
++ // or duplicating (source slower) frames. Output PTS is slot-aligned and never adjusted
++ // backward relative to the encoded frame's capture time.
++ class FrameRateAdapter
++ {
++ public:
++ FrameRateAdapter() = default;
++
++ void setRates(std::optional<double> sourceRate, double targetRate);
++
++ [[nodiscard]] bool isActive() const { return m_slotDuration > 0; }
++ [[nodiscard]] qint64 frameDuration() const { return m_slotDuration; }
++
++ // Process one frame. Returns frames to be encoded.
++ // Returns an empty queue when the frame was buffered as a pending candidate
++ // (a later frame will trigger its emission with a forward-adjusted PTS).
++ // adjustTimeBase is stored alongside the pending frame and forwarded to
++ // the first output frame when the pending candidate is eventually emitted.
++ std::vector<FrameInfo> adapt(const QVideoFrame &frame, bool adjustTimeBase = false);
++
++ std::optional<FrameInfo> flush();
++ [[nodiscard]] bool hasPendingFlush() const { return m_pendingNeedsFlush; }
++
++ // Clear all internal state (call on pause/seek).
++ void reset();
++
++ private:
++ [[nodiscard]] FrameInfo emitPendingFrame(bool keepPending = true);
++
++ qint64 m_slotDuration{ 0 }; // µs per encoder frame; 0 = inactive
++ qint64 m_nextSlotTime{ -1 }; // next slot boundary in µs; -1 = uninitialized
++ qint64 m_slotMatchEpsilon{ 0 };
++
++ std::optional<FrameInfo> m_pendingFrame;
++ std::optional<qint64> m_sourceDuration{ 0 };
++ bool m_pendingNeedsFlush{ false };
++ };
++
++ } // namespace QFFmpeg
++
++ QT_END_NAMESPACE
++
++ #endif