qffmpegmediaplayer.cpp

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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
 
#include "qffmpegmediaplayer_p.h"
#include "private/qplatformaudiooutput_p.h"
#include "qvideosink.h"
#include "qaudiooutput.h"
#include "qaudiobufferoutput.h"
 
#include "qffmpegplaybackengine_p.h"
#include <qiodevice.h>
#include <qvideosink.h>
#include <qtimer.h>
#include <QtConcurrent/QtConcurrent>
 
#include <qloggingcategory.h>
 
QT_BEGIN_NAMESPACE
 
namespace QFFmpeg {
 
class CancelToken : public ICancelToken
{
public:
 
    bool isCancelled() const override { return m_cancelled.load(std::memory_order_acquire); }
 
    void cancel() { m_cancelled.store(true, std::memory_order_release); }
 
private:
    std::atomic_bool m_cancelled = false;
};
 
} // namespace QFFmpeg
 
using namespace QFFmpeg;
 
QFFmpegMediaPlayer::QFFmpegMediaPlayer(QMediaPlayer *player)
    : QPlatformMediaPlayer(player)
{
    m_positionUpdateTimer.setInterval(50);
    m_positionUpdateTimer.setTimerType(Qt::PreciseTimer);
    connect(&m_positionUpdateTimer, &QTimer::timeout, this, &QFFmpegMediaPlayer::updatePosition);
}
 
QFFmpegMediaPlayer::~QFFmpegMediaPlayer()
{
    if (m_cancelToken)
        m_cancelToken->cancel();
 
    m_loadMedia.waitForFinished();
};
 
qint64 QFFmpegMediaPlayer::duration() const
{
    return m_playbackEngine ? m_playbackEngine->duration() / 1000 : 0;
}
 
void QFFmpegMediaPlayer::setPosition(qint64 position)
{
    if (mediaStatus() == QMediaPlayer::LoadingMedia)
        return;
 
    if (m_playbackEngine) {
        m_playbackEngine->seek(position * 1000);
        updatePosition();
    }
 
    mediaStatusChanged(QMediaPlayer::LoadedMedia);
}
 
void QFFmpegMediaPlayer::updatePosition()
{
    positionChanged(m_playbackEngine ? m_playbackEngine->currentPosition() / 1000 : 0);
}
 
void QFFmpegMediaPlayer::endOfStream()
{
    // stop update timer and report end position anyway
    m_positionUpdateTimer.stop();
    QPointer currentPlaybackEngine(m_playbackEngine.get());
    positionChanged(duration());
 
    // skip changing state and mediaStatus if playbackEngine has been recreated,
    // e.g. if new media has been loaded as a response to positionChanged signal
    if (currentPlaybackEngine)
        stateChanged(QMediaPlayer::StoppedState);
    if (currentPlaybackEngine)
        mediaStatusChanged(QMediaPlayer::EndOfMedia);
}
 
void QFFmpegMediaPlayer::onLoopChanged()
{
    // report about finish and start
    // reporting both signals is a bit contraversial
    // but it eshures the idea of notifications about
    // imporatant position points.
    // Also, it ensures more predictable flow for testing.
    positionChanged(duration());
    positionChanged(0);
    m_positionUpdateTimer.stop();
    m_positionUpdateTimer.start();
}
 
void QFFmpegMediaPlayer::onBuffered()
{
    if (mediaStatus() == QMediaPlayer::BufferingMedia)
        mediaStatusChanged(QMediaPlayer::BufferedMedia);
}
 
float QFFmpegMediaPlayer::bufferProgress() const
{
    return m_bufferProgress;
}
 
void QFFmpegMediaPlayer::mediaStatusChanged(QMediaPlayer::MediaStatus status)
{
    if (mediaStatus() == status)
        return;
 
    const auto newBufferProgress = status == QMediaPlayer::BufferingMedia ? 0.25f // to be improved
            : status == QMediaPlayer::BufferedMedia                       ? 1.f
                                                                          : 0.f;
 
    if (!qFuzzyCompare(newBufferProgress, m_bufferProgress)) {
        m_bufferProgress = newBufferProgress;
        bufferProgressChanged(newBufferProgress);
    }
 
    QPlatformMediaPlayer::mediaStatusChanged(status);
}
 
QMediaTimeRange QFFmpegMediaPlayer::availablePlaybackRanges() const
{
    return {};
}
 
qreal QFFmpegMediaPlayer::playbackRate() const
{
    return m_playbackRate;
}
 
void QFFmpegMediaPlayer::setPlaybackRate(qreal rate)
{
    const float effectiveRate = std::max(static_cast<float>(rate), 0.0f);
 
    if (qFuzzyCompare(m_playbackRate, effectiveRate))
        return;
 
    m_playbackRate = effectiveRate;
 
    if (m_playbackEngine)
        m_playbackEngine->setPlaybackRate(effectiveRate);
 
    playbackRateChanged(effectiveRate);
}
 
QUrl QFFmpegMediaPlayer::media() const
{
    return m_url;
}
 
const QIODevice *QFFmpegMediaPlayer::mediaStream() const
{
    return m_device;
}
 
void QFFmpegMediaPlayer::handleIncorrectMedia(QMediaPlayer::MediaStatus status)
{
    seekableChanged(false);
    audioAvailableChanged(false);
    videoAvailableChanged(false);
    metaDataChanged();
    mediaStatusChanged(status);
    m_playbackEngine = nullptr;
};
 
void QFFmpegMediaPlayer::setMedia(const QUrl &media, QIODevice *stream)
{
    // Wait for previous unfinished load attempts.
    if (m_cancelToken)
        m_cancelToken->cancel();
 
    m_loadMedia.waitForFinished();
 
    m_url = media;
    m_device = stream;
    m_playbackEngine = nullptr;
 
    if (media.isEmpty() && !stream) {
        handleIncorrectMedia(QMediaPlayer::NoMedia);
        return;
    }
 
    mediaStatusChanged(QMediaPlayer::LoadingMedia);
 
    m_requestedStatus = QMediaPlayer::StoppedState;
 
    m_cancelToken = std::make_shared<CancelToken>();
 
    // Load media asynchronously to keep GUI thread responsive while loading media
    m_loadMedia = QtConcurrent::run([this, media, stream, cancelToken = m_cancelToken] {
        // On worker thread
        const MediaDataHolder::Maybe mediaHolder =
                MediaDataHolder::create(media, stream, cancelToken);
 
        // Transition back to calling thread using invokeMethod because
        // QFuture continuations back on calling thread may deadlock (QTBUG-117918)
        QMetaObject::invokeMethod(this, [this, mediaHolder, cancelToken] {
            setMediaAsync(mediaHolder, cancelToken);
        });
    });
}
 
void QFFmpegMediaPlayer::setMediaAsync(QFFmpeg::MediaDataHolder::Maybe mediaDataHolder,
                                       const std::shared_ptr<QFFmpeg::CancelToken> &cancelToken)
{
    Q_ASSERT(mediaStatus() == QMediaPlayer::LoadingMedia);
 
    // If loading was cancelled, we do not emit any signals about failing
    // to load media (or any other events). The rationale is that cancellation
    // either happens during destruction, where the signals are no longer
    // of interest, or it happens as a response to user requesting to load
    // another media file. In the latter case, we don't want to risk popping
    // up error dialogs or similar.
    if (cancelToken->isCancelled()) {
        return;
    }
 
    if (!mediaDataHolder) {
        const auto [code, description] = mediaDataHolder.error();
        error(code, description);
        handleIncorrectMedia(QMediaPlayer::MediaStatus::InvalidMedia);
        return;
    }
 
    m_playbackEngine = std::make_unique<PlaybackEngine>();
 
    connect(m_playbackEngine.get(), &PlaybackEngine::endOfStream, this,
            &QFFmpegMediaPlayer::endOfStream);
    connect(m_playbackEngine.get(), &PlaybackEngine::errorOccured, this,
            &QFFmpegMediaPlayer::error);
    connect(m_playbackEngine.get(), &PlaybackEngine::loopChanged, this,
            &QFFmpegMediaPlayer::onLoopChanged);
    connect(m_playbackEngine.get(), &PlaybackEngine::buffered, this,
            &QFFmpegMediaPlayer::onBuffered);
 
    m_playbackEngine->setMedia(std::move(*mediaDataHolder.value()));
 
    m_playbackEngine->setAudioBufferOutput(m_audioBufferOutput);
    m_playbackEngine->setAudioSink(m_audioOutput);
    m_playbackEngine->setVideoSink(m_videoSink);
 
    m_playbackEngine->setLoops(loops());
    m_playbackEngine->setPlaybackRate(m_playbackRate);
 
    durationChanged(duration());
    tracksChanged();
    metaDataChanged();
    seekableChanged(m_playbackEngine->isSeekable());
 
    audioAvailableChanged(
            !m_playbackEngine->streamInfo(QPlatformMediaPlayer::AudioStream).isEmpty());
    videoAvailableChanged(
            !m_playbackEngine->streamInfo(QPlatformMediaPlayer::VideoStream).isEmpty());
 
    mediaStatusChanged(QMediaPlayer::LoadedMedia);
 
    if (m_requestedStatus != QMediaPlayer::StoppedState) {
        if (m_requestedStatus == QMediaPlayer::PlayingState)
            play();
        else if (m_requestedStatus == QMediaPlayer::PausedState)
            pause();
    }
}
 
void QFFmpegMediaPlayer::play()
{
    if (mediaStatus() == QMediaPlayer::LoadingMedia) {
        m_requestedStatus = QMediaPlayer::PlayingState;
        return;
    }
 
    if (!m_playbackEngine)
        return;
 
    if (mediaStatus() == QMediaPlayer::EndOfMedia && state() == QMediaPlayer::StoppedState) {
        m_playbackEngine->seek(0);
        positionChanged(0);
    }
 
    runPlayback();
}
 
void QFFmpegMediaPlayer::runPlayback()
{
    m_playbackEngine->play();
    m_positionUpdateTimer.start();
    stateChanged(QMediaPlayer::PlayingState);
 
    if (mediaStatus() == QMediaPlayer::LoadedMedia || mediaStatus() == QMediaPlayer::EndOfMedia)
        mediaStatusChanged(QMediaPlayer::BufferingMedia);
}
 
void QFFmpegMediaPlayer::pause()
{
    if (mediaStatus() == QMediaPlayer::LoadingMedia) {
        m_requestedStatus = QMediaPlayer::PausedState;
        return;
    }
 
    if (!m_playbackEngine)
        return;
 
    if (mediaStatus() == QMediaPlayer::EndOfMedia && state() == QMediaPlayer::StoppedState) {
        m_playbackEngine->seek(0);
        positionChanged(0);
    }
    m_playbackEngine->pause();
    m_positionUpdateTimer.stop();
    stateChanged(QMediaPlayer::PausedState);
 
    if (mediaStatus() == QMediaPlayer::LoadedMedia || mediaStatus() == QMediaPlayer::EndOfMedia)
        mediaStatusChanged(QMediaPlayer::BufferingMedia);
}
 
void QFFmpegMediaPlayer::stop()
{
    if (mediaStatus() == QMediaPlayer::LoadingMedia) {
        m_requestedStatus = QMediaPlayer::StoppedState;
        return;
    }
 
    if (!m_playbackEngine)
        return;
 
    m_playbackEngine->stop();
    m_positionUpdateTimer.stop();
    m_playbackEngine->seek(0);
    positionChanged(0);
    stateChanged(QMediaPlayer::StoppedState);
    mediaStatusChanged(QMediaPlayer::LoadedMedia);
}
 
void QFFmpegMediaPlayer::setAudioOutput(QPlatformAudioOutput *output)
{
    m_audioOutput = output;
    if (m_playbackEngine)
        m_playbackEngine->setAudioSink(output);
}
 
void QFFmpegMediaPlayer::setAudioBufferOutput(QAudioBufferOutput *output) {
    m_audioBufferOutput = output;
    if (m_playbackEngine)
        m_playbackEngine->setAudioBufferOutput(output);
}
 
QMediaMetaData QFFmpegMediaPlayer::metaData() const
{
    return m_playbackEngine ? m_playbackEngine->metaData() : QMediaMetaData{};
}
 
void QFFmpegMediaPlayer::setVideoSink(QVideoSink *sink)
{
    m_videoSink = sink;
    if (m_playbackEngine)
        m_playbackEngine->setVideoSink(sink);
}
 
QVideoSink *QFFmpegMediaPlayer::videoSink() const
{
    return m_videoSink;
}
 
int QFFmpegMediaPlayer::trackCount(TrackType type)
{
    return m_playbackEngine ? m_playbackEngine->streamInfo(type).count() : 0;
}
 
QMediaMetaData QFFmpegMediaPlayer::trackMetaData(TrackType type, int streamNumber)
{
    if (!m_playbackEngine || streamNumber < 0
        || streamNumber >= m_playbackEngine->streamInfo(type).count())
        return {};
    return m_playbackEngine->streamInfo(type).at(streamNumber).metaData;
}
 
int QFFmpegMediaPlayer::activeTrack(TrackType type)
{
    return m_playbackEngine ? m_playbackEngine->activeTrack(type) : -1;
}
 
void QFFmpegMediaPlayer::setActiveTrack(TrackType type, int streamNumber)
{
    if (m_playbackEngine)
        m_playbackEngine->setActiveTrack(type, streamNumber);
    else
        qWarning() << "Cannot set active track without open source";
}
 
void QFFmpegMediaPlayer::setLoops(int loops)
{
    if (m_playbackEngine)
        m_playbackEngine->setLoops(loops);
 
    QPlatformMediaPlayer::setLoops(loops);
}
 
QT_END_NAMESPACE
 
#include "moc_qffmpegmediaplayer_p.cpp"