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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 "playbackengine/qffmpegdemuxer_p.h"
#include <qloggingcategory.h>
QT_BEGIN_NAMESPACE
// 4 sec for buffering. TODO: maybe move to env var customization
static constexpr qint64 MaxBufferedDurationUs = 4'000'000;
// around 4 sec of hdr video
static constexpr qint64 MaxBufferedSize = 32 * 1024 * 1024;
namespace QFFmpeg {
static Q_LOGGING_CATEGORY(qLcDemuxer, "qt.multimedia.ffmpeg.demuxer");
static qint64 streamTimeToUs(const AVStream *stream, qint64 time)
{
Q_ASSERT(stream);
const auto res = mul(time * 1000000, stream->time_base);
return res ? *res : time;
}
static qint64 packetEndPos(const AVStream *stream, const Packet &packet)
{
return packet.loopOffset().pos
+ streamTimeToUs(stream, packet.avPacket()->pts + packet.avPacket()->duration);
}
Demuxer::Demuxer(AVFormatContext *context, const PositionWithOffset &posWithOffset,
const StreamIndexes &streamIndexes, int loops)
: m_context(context), m_posWithOffset(posWithOffset), m_loops(loops)
{
qCDebug(qLcDemuxer) << "Create demuxer."
<< "pos:" << posWithOffset.pos << "loop offset:" << posWithOffset.offset.pos
<< "loop index:" << posWithOffset.offset.index << "loops:" << loops;
Q_ASSERT(m_context);
Q_ASSERT(loops < 0 || m_posWithOffset.offset.index < loops);
for (auto i = 0; i < QPlatformMediaPlayer::NTrackTypes; ++i) {
if (streamIndexes[i] >= 0) {
const auto trackType = static_cast<QPlatformMediaPlayer::TrackType>(i);
qCDebug(qLcDemuxer) << "Activate demuxing stream" << i << ", trackType:" << trackType;
m_streams[streamIndexes[i]] = { trackType };
}
}
}
void Demuxer::doNextStep()
{
ensureSeeked();
Packet packet(m_posWithOffset.offset, AVPacketUPtr{ av_packet_alloc() }, id());
if (av_read_frame(m_context, packet.avPacket()) < 0) {
++m_posWithOffset.offset.index;
const auto loops = m_loops.loadAcquire();
if (loops >= 0 && m_posWithOffset.offset.index >= loops) {
qCDebug(qLcDemuxer) << "finish demuxing";
if (!std::exchange(m_buffered, true))
emit packetsBuffered();
setAtEnd(true);
} else {
m_seeked = false;
m_posWithOffset.pos = 0;
m_posWithOffset.offset.pos = m_maxPacketsEndPos;
m_maxPacketsEndPos = 0;
ensureSeeked();
qCDebug(qLcDemuxer) << "Demuxer loops changed. Index:" << m_posWithOffset.offset.index
<< "Offset:" << m_posWithOffset.offset.pos;
scheduleNextStep(false);
}
return;
}
auto &avPacket = *packet.avPacket();
const auto streamIndex = avPacket.stream_index;
const auto stream = m_context->streams[streamIndex];
auto it = m_streams.find(streamIndex);
if (it != m_streams.end()) {
auto &streamData = it->second;
const auto endPos = packetEndPos(stream, packet);
m_maxPacketsEndPos = qMax(m_maxPacketsEndPos, endPos);
// Increase buffered metrics as the packet has been processed.
streamData.bufferedDuration += streamTimeToUs(stream, avPacket.duration);
streamData.bufferedSize += avPacket.size;
streamData.maxSentPacketsPos = qMax(streamData.maxSentPacketsPos, endPos);
updateStreamDataLimitFlag(streamData);
if (!m_buffered && streamData.isDataLimitReached) {
m_buffered = true;
emit packetsBuffered();
}
if (!m_firstPacketFound) {
m_firstPacketFound = true;
const auto pos = streamTimeToUs(stream, avPacket.pts);
emit firstPacketFound(std::chrono::steady_clock::now(), pos);
}
auto signal = signalByTrackType(it->second.trackType);
emit (this->*signal)(packet);
}
scheduleNextStep(false);
}
void Demuxer::onPacketProcessed(Packet packet)
{
Q_ASSERT(packet.isValid());
if (packet.sourceId() != id())
return;
auto &avPacket = *packet.avPacket();
const auto streamIndex = avPacket.stream_index;
const auto stream = m_context->streams[streamIndex];
auto it = m_streams.find(streamIndex);
if (it != m_streams.end()) {
auto &streamData = it->second;
// Decrease buffered metrics as new data (the packet) has been received (buffered)
streamData.bufferedDuration -= streamTimeToUs(stream, avPacket.duration);
streamData.bufferedSize -= avPacket.size;
streamData.maxProcessedPacketPos =
qMax(streamData.maxProcessedPacketPos, packetEndPos(stream, packet));
Q_ASSERT(it->second.bufferedDuration >= 0);
Q_ASSERT(it->second.bufferedSize >= 0);
updateStreamDataLimitFlag(streamData);
}
scheduleNextStep();
}
bool Demuxer::canDoNextStep() const
{
auto isDataLimitReached = [](const auto &streamIndexToData) {
return streamIndexToData.second.isDataLimitReached;
};
// Demuxer waits:
// - if it's paused
// - if the end has been reached
// - if streams are empty (probably, should be handled on the initialization)
// - if at least one of the streams has reached the data limit (duration or size)
return PlaybackEngineObject::canDoNextStep() && !isAtEnd() && !m_streams.empty()
&& std::none_of(m_streams.begin(), m_streams.end(), isDataLimitReached);
}
void Demuxer::ensureSeeked()
{
if (std::exchange(m_seeked, true))
return;
if ((m_context->ctx_flags & AVFMTCTX_UNSEEKABLE) == 0) {
const qint64 seekPos = m_posWithOffset.pos * AV_TIME_BASE / 1000000;
auto err = av_seek_frame(m_context, -1, seekPos, AVSEEK_FLAG_BACKWARD);
if (err < 0) {
qCWarning(qLcDemuxer) << "Failed to seek, pos" << seekPos;
// Drop an error of seeking to initial position of streams with undefined duration.
// This needs improvements.
if (seekPos != 0 || m_context->duration > 0)
emit error(QMediaPlayer::ResourceError,
QLatin1StringView("Failed to seek: ") + err2str(err));
}
}
setAtEnd(false);
}
Demuxer::RequestingSignal Demuxer::signalByTrackType(QPlatformMediaPlayer::TrackType trackType)
{
switch (trackType) {
case QPlatformMediaPlayer::TrackType::VideoStream:
return &Demuxer::requestProcessVideoPacket;
case QPlatformMediaPlayer::TrackType::AudioStream:
return &Demuxer::requestProcessAudioPacket;
case QPlatformMediaPlayer::TrackType::SubtitleStream:
return &Demuxer::requestProcessSubtitlePacket;
default:
Q_ASSERT(!"Unknown track type");
}
return nullptr;
}
void Demuxer::setLoops(int loopsCount)
{
qCDebug(qLcDemuxer) << "setLoops to demuxer" << loopsCount;
m_loops.storeRelease(loopsCount);
}
void Demuxer::updateStreamDataLimitFlag(StreamData &streamData)
{
const auto packetsPosDiff = streamData.maxSentPacketsPos - streamData.maxProcessedPacketPos;
streamData.isDataLimitReached =
streamData.bufferedDuration >= MaxBufferedDurationUs
|| (streamData.bufferedDuration == 0 && packetsPosDiff >= MaxBufferedDurationUs)
|| streamData.bufferedSize >= MaxBufferedSize;
}
} // namespace QFFmpeg
QT_END_NAMESPACE
#include "moc_qffmpegdemuxer_p.cpp"
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