GstVideoReceiver.cc

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//-----------------------------------------------------------------------------
// Our pipeline look like this:
//
//              +-->queue-->_decoderValve[-->_decoder-->_videoSink]
//              |
// _source-->_tee
//              |
//              +-->queue-->_recorderValve[-->_fileSink]
//-----------------------------------------------------------------------------
 
#include "GstVideoReceiver.h"
 
#if defined(QGC_HAS_GST_D3D11_GPU_PATH)
#include "HwBuffers/GstD3D11ContextBridge.h"
#endif
#if defined(QGC_HAS_GST_D3D12_GPU_PATH)
#include "HwBuffers/GstD3D12ContextBridge.h"
#endif
#include "GStreamerHelpers.h"
#include "QGCLoggingCategory.h"
 
#include <QtCore/QDateTime>
#include <QtCore/QUrl>
#include <QtQuick/QQuickItem>
 
#include <gst/gst.h>
#include <gst/video/video.h>
 
QGC_LOGGING_CATEGORY(GstVideoReceiverLog, "Video.GStreamer.GstVideoReceiver")
 
#if defined(QGC_HAS_GST_GLMEMORY_GPU_PATH) || defined(QGC_HAS_GST_D3D11_GPU_PATH) || defined(QGC_HAS_GST_D3D12_GPU_PATH)
#include "HwBuffers/GstContextBridgeRegistry.h"
namespace {
GstBusSyncReply _contextSyncDispatch(GstBus * /*bus*/, GstMessage *message, gpointer /*data*/)
{
    return GstContextBridgeRegistry::dispatchBridges(message);
}
} // namespace
#endif
 
GstVideoReceiver::GstVideoReceiver(QObject *parent)
    : VideoReceiver(parent)
    , _worker(new GstVideoWorker(this))
{
    qCDebug(GstVideoReceiverLog) << this;
 
    _worker->start();
    (void) connect(&_watchdogTimer, &QTimer::timeout, this, &GstVideoReceiver::_watchdog);
}
 
GstVideoReceiver::~GstVideoReceiver()
{
    stop();
    _worker->shutdown();
 
    qCDebug(GstVideoReceiverLog) << this;
}
 
void GstVideoReceiver::start(uint32_t timeout)
{
    if (_needDispatch()) {
        _worker->dispatch([this, timeout]() { start(timeout); });
        return;
    }
 
    if (_pipeline) {
        qCDebug(GstVideoReceiverLog) << "Already running!" << _uri;
        _dispatchSignal([this]() { emit onStartComplete(STATUS_INVALID_STATE); });
        return;
    }
 
    if (_uri.isEmpty()) {
        qCDebug(GstVideoReceiverLog) << "Failed because URI is not specified";
        _dispatchSignal([this]() { emit onStartComplete(STATUS_INVALID_URL); });
        return;
    }
 
    _timeout = timeout;
    _buffer = lowLatency() ? -1 : 0;
 
    qCDebug(GstVideoReceiverLog) << "Starting" << _uri << ", lowLatency" << lowLatency() << ", timeout" << _timeout;
 
    _endOfStream = false;
 
    bool running = false;
    bool pipelineUp = false;
 
    GstElement *decoderQueue = nullptr;
    GstElement *recorderQueue = nullptr;
 
    do {
        _tee = gst_element_factory_make("tee", nullptr);
        if (!_tee)  {
            qCCritical(GstVideoReceiverLog) << "gst_element_factory_make('tee') failed";
            break;
        }
 
        GstPad *pad = gst_element_get_static_pad(_tee, "sink");
        if (!pad) {
            qCCritical(GstVideoReceiverLog) << "gst_element_get_static_pad() failed";
            break;
        }
 
        _lastSourceFrameTime = 0;
 
        _teeProbeId = gst_pad_add_probe(pad, GST_PAD_PROBE_TYPE_BUFFER, _teeProbe, this, nullptr);
        gst_clear_object(&pad);
        if (_teeProbeId == 0) {
            // _teeProbe updates _lastSourceFrameTime; without it the watchdog timer fires spuriously instead of reporting a real failure.
            qCCritical(GstVideoReceiverLog) << "gst_pad_add_probe(_teeProbe) failed";
            break;
        }
 
        decoderQueue = gst_element_factory_make("queue", nullptr);
        if (!decoderQueue)  {
            qCCritical(GstVideoReceiverLog) << "gst_element_factory_make('queue') failed";
            break;
        }
 
        _decoderValve = gst_element_factory_make("valve", nullptr);
        if (!_decoderValve)  {
            qCCritical(GstVideoReceiverLog) << "gst_element_factory_make('valve') failed";
            break;
        }
 
        g_object_set(_decoderValve,
                     "drop", TRUE,
                     nullptr);
 
        recorderQueue = gst_element_factory_make("queue", nullptr);
        if (!recorderQueue)  {
            qCCritical(GstVideoReceiverLog) << "gst_element_factory_make('queue') failed";
            break;
        }
 
        _recorderValve = gst_element_factory_make("valve", nullptr);
        if (!_recorderValve) {
            qCCritical(GstVideoReceiverLog) << "gst_element_factory_make('valve') failed";
            break;
        }
 
        g_object_set(_recorderValve,
                     "drop", TRUE,
                     nullptr);
 
        _pipeline = gst_pipeline_new("receiver");
        if (!_pipeline) {
            qCCritical(GstVideoReceiverLog) << "gst_pipeline_new() failed";
            break;
        }
 
        g_object_set(_pipeline,
                     "message-forward", TRUE,
                     nullptr);
 
        _source = _makeSource(_uri);
        if (!_source) {
            qCCritical(GstVideoReceiverLog) << "_makeSource() failed";
            break;
        }
 
        gst_bin_add_many(GST_BIN(_pipeline), _source, _tee, decoderQueue, _decoderValve, recorderQueue, _recorderValve, nullptr);
 
        pipelineUp = true;
 
        GstPad *srcPad = nullptr;
        GstIterator *it = gst_element_iterate_src_pads(_source);
        GValue vpad = G_VALUE_INIT;
        switch (gst_iterator_next(it, &vpad)) {
            case GST_ITERATOR_OK:
                srcPad = GST_PAD(g_value_get_object(&vpad));
                (void) gst_object_ref(srcPad);
                (void) g_value_reset(&vpad);
                break;
            case GST_ITERATOR_RESYNC:
                gst_iterator_resync(it);
                break;
            default:
                break;
        }
        g_value_unset(&vpad);
        gst_iterator_free(it);
 
        if (srcPad) {
            _onNewSourcePad(srcPad);
            gst_clear_object(&srcPad);
        } else {
            (void) g_signal_connect(_source, "pad-added", G_CALLBACK(_onNewPad), this);
        }
 
        if (!gst_element_link_many(_tee, decoderQueue, _decoderValve, nullptr)) {
            qCCritical(GstVideoReceiverLog) << "Unable to link decoder queue";
            break;
        }
 
        if (!gst_element_link_many(_tee, recorderQueue, _recorderValve, nullptr)) {
            qCCritical(GstVideoReceiverLog) << "Unable to link recorder queue";
            break;
        }
 
        GstBus *bus = gst_pipeline_get_bus(GST_PIPELINE(_pipeline));
        if (bus) {
            gst_bus_enable_sync_message_emission(bus);
            (void) g_signal_connect(bus, "sync-message", G_CALLBACK(_onBusMessage), this);
#if defined(QGC_HAS_GST_GLMEMORY_GPU_PATH) || defined(QGC_HAS_GST_D3D11_GPU_PATH) || defined(QGC_HAS_GST_D3D12_GPU_PATH)
            // Single sync dispatcher chains every compiled context bridge so
            // they don't clobber each other via gst_bus_set_sync_handler. Must
            // run before GST_STATE_PLAYING — upstream queries context during
            // PAUSED→PLAYING. Each bridge cheap-rejects messages it doesn't
            // serve, so total cost on irrelevant messages is a strcmp.
            gst_bus_set_sync_handler(bus, _contextSyncDispatch, nullptr, nullptr);
#endif
            gst_clear_object(&bus);
        }
 
        GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(_pipeline), GST_DEBUG_GRAPH_SHOW_ALL, "pipeline-initial");
        running = (gst_element_set_state(_pipeline, GST_STATE_PLAYING) != GST_STATE_CHANGE_FAILURE);
    } while(0);
 
    if (!running) {
        qCCritical(GstVideoReceiverLog) << "Failed";
 
        if (_pipeline) {
            (void) gst_element_set_state(_pipeline, GST_STATE_NULL);
            (void) gst_element_get_state(_pipeline, nullptr, nullptr, GST_CLOCK_TIME_NONE);
            gst_clear_object(&_pipeline);
        }
 
        if (!pipelineUp) {
            gst_clear_object(&_recorderValve);
            gst_clear_object(&recorderQueue);
            gst_clear_object(&_decoderValve);
            gst_clear_object(&decoderQueue);
            gst_clear_object(&_tee);
            gst_clear_object(&_source);
        }
 
        // Rate limit restarts on failure. This sleep is OK because we're in the video worker thread.
        QThread::sleep(1);
        _dispatchSignal([this]() { emit onStartComplete(STATUS_FAIL); });
    } else {
        GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(_pipeline), GST_DEBUG_GRAPH_SHOW_ALL, "pipeline-started");
        qCDebug(GstVideoReceiverLog) << "Started" << _uri;
 
        // _watchdogTimer lives on `this` (GUI thread); _dispatchSignal runs synchronously on the
        // worker thread, so the timer start has to be queued separately or QObject warns.
        QMetaObject::invokeMethod(this, [this]() { _watchdogTimer.start(1000); }, Qt::QueuedConnection);
        _dispatchSignal([this]() { emit onStartComplete(STATUS_OK); });
    }
}
 
void GstVideoReceiver::stop()
{
    if (_needDispatch()) {
        _worker->dispatch([this]() { stop(); });
        return;
    }
 
    if (_uri.isEmpty()) {
        qCDebug(GstVideoReceiverLog) << "Stop called on empty URI (no-op)";
        return;
    }
 
    qCDebug(GstVideoReceiverLog) << "Stopping" << _uri;
 
    QMetaObject::invokeMethod(this, [this]() { _watchdogTimer.stop(); }, Qt::QueuedConnection);
 
    if (_teeProbeId != 0) {
        if (_tee) {
            GstPad *sinkpad = gst_element_get_static_pad(_tee, "sink");
            if (sinkpad) {
                gst_pad_remove_probe(sinkpad, _teeProbeId);
                gst_clear_object(&sinkpad);
            }
        }
        _teeProbeId = 0;
    }
 
    if (_pipeline) {
        GstBus *bus = gst_pipeline_get_bus(GST_PIPELINE(_pipeline));
        if (bus) {
            gst_bus_disable_sync_message_emission(bus);
            (void) g_signal_handlers_disconnect_by_data(bus, this);
 
            gboolean recordingValveClosed = TRUE;
            g_object_get(_recorderValve, "drop", &recordingValveClosed, nullptr);
 
            if (!recordingValveClosed) {
                (void) gst_element_send_event(_pipeline, gst_event_new_eos());
 
                GstMessage *msg = gst_bus_timed_pop_filtered(bus, GST_CLOCK_TIME_NONE, (GstMessageType)(GST_MESSAGE_EOS | GST_MESSAGE_ERROR));
                if (msg) {
                    switch (GST_MESSAGE_TYPE(msg)) {
                    case GST_MESSAGE_EOS:
                        qCDebug(GstVideoReceiverLog) << "End of stream received!";
                        break;
                    case GST_MESSAGE_ERROR:
                        qCCritical(GstVideoReceiverLog) << "Error stopping pipeline!";
                        break;
                    default:
                        break;
                    }
 
                    gst_clear_message(&msg);
                } else {
                    qCCritical(GstVideoReceiverLog) << "gst_bus_timed_pop_filtered() failed";
                }
            }
 
            gst_clear_object(&bus);
        } else {
            qCCritical(GstVideoReceiverLog) << "gst_pipeline_get_bus() failed";
        }
 
        (void) gst_element_set_state(_pipeline, GST_STATE_NULL);
        (void) gst_element_get_state(_pipeline, nullptr, nullptr, GST_CLOCK_TIME_NONE);
 
        // FIXME: check if branch is connected and remove all elements from branch
        if (_fileSink) {
           _shutdownRecordingBranch();
        }
 
        if (_videoSink) {
            _shutdownDecodingBranch();
        }
 
        GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(_pipeline), GST_DEBUG_GRAPH_SHOW_ALL, "pipeline-stopped");
 
        gst_clear_object(&_pipeline);
        _pipeline = nullptr;
 
        _recorderValve = nullptr;
        _decoderValve = nullptr;
        _tee = nullptr;
        _source = nullptr;
 
        _lastSourceFrameTime = 0;
 
        if (_streaming) {
            _streaming = false;
            qCDebug(GstVideoReceiverLog) << "Streaming stopped" << _uri;
            _dispatchSignal([this]() { emit streamingChanged(_streaming); });
        } else {
            qCDebug(GstVideoReceiverLog) << "Streaming did not start" << _uri;
        }
    }
 
    qCDebug(GstVideoReceiverLog) << "Stopped" << _uri;
 
    _dispatchSignal([this]() { emit onStopComplete(STATUS_OK); });
}
 
void GstVideoReceiver::startDecoding(void *sink)
{
    if (!sink) {
        qCCritical(GstVideoReceiverLog) << "VideoSink is NULL" << _uri;
        return;
    }
 
    if (_needDispatch()) {
        _worker->dispatch([this, sink]() mutable { startDecoding(sink); });
        return;
    }
 
    qCDebug(GstVideoReceiverLog) << "Starting decoding" << _uri;
 
    if (!_widget) {
        qCDebug(GstVideoReceiverLog) << "Video Widget is NULL" << _uri;
        _dispatchSignal([this]() { emit onStartDecodingComplete(STATUS_FAIL); });
        return;
    }
 
    if (!_pipeline) {
        gst_clear_object(&_videoSink);
    }
 
    if (_videoSink || _decoding) {
        qCDebug(GstVideoReceiverLog) << "Already decoding!" << _uri;
        _dispatchSignal([this]() { emit onStartDecodingComplete(STATUS_INVALID_STATE); });
        return;
    }
 
    GstElement *videoSink = GST_ELEMENT(sink);
    GstPad *pad = gst_element_get_static_pad(videoSink, "sink");
    if (!pad) {
        qCCritical(GstVideoReceiverLog) << "Unable to find sink pad of video sink" << _uri;
        _dispatchSignal([this]() { emit onStartDecodingComplete(STATUS_FAIL); });
        return;
    }
 
    _lastVideoFrameTime = 0;
    _resetVideoSink = true;
 
    _videoSinkProbeId = gst_pad_add_probe(pad, GST_PAD_PROBE_TYPE_BUFFER, _videoSinkProbe, this, nullptr);
    gst_clear_object(&pad);
 
    _videoSink = videoSink;
    gst_object_ref(_videoSink);
 
    _removingDecoder = false;
 
    if (!_streaming) {
        _dispatchSignal([this]() { emit onStartDecodingComplete(STATUS_OK); });
        return;
    }
 
    _ensureVideoSinkInPipeline();
 
    if (!_addDecoder(_decoderValve)) {
        qCCritical(GstVideoReceiverLog) << "_addDecoder() failed" << _uri;
        _shutdownDecodingBranch();
        _dispatchSignal([this]() { emit onStartDecodingComplete(STATUS_FAIL); });
        return;
    }
 
    g_object_set(_decoderValve,
                 "drop", FALSE,
                 nullptr);
 
    qCDebug(GstVideoReceiverLog) << "Decoding started" << _uri;
 
    _dispatchSignal([this]() { emit onStartDecodingComplete(STATUS_OK); });
}
 
void GstVideoReceiver::stopDecoding()
{
    if (_needDispatch()) {
        _worker->dispatch([this]() { stopDecoding(); });
        return;
    }
 
    qCDebug(GstVideoReceiverLog) << "Stopping decoding" << _uri;
 
    // Gate on _videoSink (set by startDecoding) instead of _decoding (which only flips on
    // first sink-buffer probe). Without this, stopDecoding() called between
    // onStartDecodingComplete(OK) and the first frame returns STATUS_INVALID_STATE and
    // leaves the decoder/sink branch live.
    if (!_pipeline || !_videoSink) {
        qCDebug(GstVideoReceiverLog) << "Not decoding!" << _uri;
        _dispatchSignal([this]() { emit onStopDecodingComplete(STATUS_INVALID_STATE); });
        return;
    }
 
    g_object_set(_decoderValve,
                 "drop", TRUE,
                 nullptr);
 
    _removingDecoder = true;
 
    const bool ret = _unlinkBranch(_decoderValve);
 
    // FIXME: it is much better to emit onStopDecodingComplete() after decoding is really stopped
    // (which happens later due to async design) but as for now it is also not so bad...
    _dispatchSignal([this, ret](){ emit onStopDecodingComplete(ret ? STATUS_OK : STATUS_FAIL); });
}
 
void GstVideoReceiver::startRecording(const QString &videoFile, FILE_FORMAT format)
{
    if (_needDispatch()) {
        const QString cachedVideoFile = videoFile;
        _worker->dispatch([this, cachedVideoFile, format]() { startRecording(cachedVideoFile, format); });
        return;
    }
 
    qCDebug(GstVideoReceiverLog) << "Starting recording" << _uri;
 
    if (!_pipeline) {
        qCDebug(GstVideoReceiverLog) << "Streaming is not active!" << _uri;
        _dispatchSignal([this](){ emit onStartRecordingComplete(STATUS_INVALID_STATE); });
        return;
    }
 
    if (_recording) {
        qCDebug(GstVideoReceiverLog) << "Already recording!" << _uri;
        _dispatchSignal([this]() { emit onStartRecordingComplete(STATUS_INVALID_STATE); });
        return;
    }
 
    qCDebug(GstVideoReceiverLog) << "New video file:" << videoFile << _uri;
 
    _fileSink = _makeFileSink(videoFile, format);
    if (!_fileSink) {
        qCCritical(GstVideoReceiverLog) << "_makeFileSink() failed" << _uri;
        _dispatchSignal([this]() { emit onStartRecordingComplete(STATUS_FAIL); });
        return;
    }
 
    _removingRecorder = false;
 
    (void) gst_object_ref(_fileSink);
 
    gst_bin_add(GST_BIN(_pipeline), _fileSink);
 
    if (!gst_element_link(_recorderValve, _fileSink)) {
        qCCritical(GstVideoReceiverLog) << "Failed to link valve and file sink" << _uri;
        _dispatchSignal([this]() { emit onStartRecordingComplete(STATUS_FAIL); });
        return;
    }
 
    (void) gst_element_sync_state_with_parent(_fileSink);
 
    GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(_pipeline), GST_DEBUG_GRAPH_SHOW_ALL, "pipeline-with-filesink");
 
    // Install a probe on the recording branch to drop buffers until we hit our first keyframe
    // When we hit our first keyframe, we can offset the timestamps appropriately according to the first keyframe time
    // This will ensure the first frame is a keyframe at t=0, and decoding can begin immediately on playback
    GstPad *probepad = gst_element_get_static_pad(_recorderValve, "src");
    if (!probepad) {
        qCCritical(GstVideoReceiverLog) << "gst_element_get_static_pad() failed" << _uri;
        _dispatchSignal([this]() { emit onStartRecordingComplete(STATUS_FAIL); });
        return;
    }
 
    _keyframeWatchId = gst_pad_add_probe(probepad, GST_PAD_PROBE_TYPE_BUFFER, _keyframeWatch, this, nullptr);
    gst_clear_object(&probepad);
 
    g_object_set(_recorderValve,
                 "drop", FALSE,
                 nullptr);
 
    _recordingOutput = videoFile;
    _recording = true;
    qCDebug(GstVideoReceiverLog) << "Recording started" << _uri;
    _dispatchSignal([this]() {
        emit onStartRecordingComplete(STATUS_OK);
        emit recordingChanged(_recording);
    });
}
 
void GstVideoReceiver::stopRecording()
{
    if (_needDispatch()) {
        _worker->dispatch([this]() { stopRecording(); });
        return;
    }
 
    qCDebug(GstVideoReceiverLog) << "Stopping recording" << _uri;
 
    if (!_pipeline || !_recording) {
        qCDebug(GstVideoReceiverLog) << "Not recording!" << _uri;
        _dispatchSignal([this]() { emit onStopRecordingComplete(STATUS_INVALID_STATE); });
        return;
    }
 
    g_object_set(_recorderValve,
                 "drop", TRUE,
                 nullptr);
 
    _removingRecorder = true;
 
    if (!_unlinkBranch(_recorderValve)) {
        _removingRecorder = false;
        _dispatchSignal([this]() { emit onStopRecordingComplete(STATUS_FAIL); });
        return;
    }
 
    // EOS event propagates valve→mux→filesink; _shutdownRecordingBranch emits the
    // complete signal once the muxer index is written and the file is closed.
    _recordingStopRequested = true;
}
 
void GstVideoReceiver::takeScreenshot(const QString &imageFile)
{
    if (_needDispatch()) {
        const QString cachedImageFile = imageFile;
        _worker->dispatch([this, cachedImageFile]() { takeScreenshot(cachedImageFile); });
        return;
    }
 
    qCDebug(GstVideoReceiverLog) << "taking screenshot" << _uri;
 
    // FIXME: record screenshot here
    _dispatchSignal([this]() { emit onTakeScreenshotComplete(STATUS_NOT_IMPLEMENTED); });
}
 
void GstVideoReceiver::_watchdog()
{
    _worker->dispatch([this]() {
        if (!_pipeline) {
            return;
        }
 
        const qint64 now = QDateTime::currentSecsSinceEpoch();
        if (_lastSourceFrameTime == 0) {
            _lastSourceFrameTime = now;
        }
 
        qint64 elapsed = now - _lastSourceFrameTime;
        if (elapsed > _timeout) {
            qCDebug(GstVideoReceiverLog) << "Stream timeout, no frames for" << elapsed << _uri;
            GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(_pipeline), GST_DEBUG_GRAPH_SHOW_ALL, "pipeline-watchdog-timeout");
            _dispatchSignal([this]() { emit timeout(); });
            stop();
        }
 
        if (_decoding && !_removingDecoder) {
            if (_lastVideoFrameTime == 0) {
                _lastVideoFrameTime = now;
            }
 
            elapsed = now - _lastVideoFrameTime;
            if (elapsed > (_timeout * 2)) {
                qCDebug(GstVideoReceiverLog) << "Video decoder timeout, no frames for" << elapsed << _uri;
                GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(_pipeline), GST_DEBUG_GRAPH_SHOW_ALL, "pipeline-watchdog-timeout");
                _dispatchSignal([this]() { emit timeout(); });
                stop();
            }
        }
    });
}
 
void GstVideoReceiver::_handleEOS()
{
    if (!_pipeline) {
        return;
    }
 
    if (_endOfStream) {
        stop();
    } else if (_decoding && _removingDecoder) {
        _shutdownDecodingBranch();
    } else if (_recording && _removingRecorder) {
        _shutdownRecordingBranch();
    } /*else {
        qCWarning(GstVideoReceiverLog) << "Unexpected EOS!";
        stop();
    }*/
}
 
#if !defined(QGC_GST_BUILD_VERSION_MAJOR) || (QGC_GST_BUILD_VERSION_MAJOR == 1 && QGC_GST_BUILD_VERSION_MINOR < 28)
gboolean GstVideoReceiver::_filterParserCaps(GstElement *bin, GstPad *pad, GstElement *element, GstQuery *query, gpointer data)
{
    Q_UNUSED(bin); Q_UNUSED(pad); Q_UNUSED(element); Q_UNUSED(data)
 
    if (GST_QUERY_TYPE(query) != GST_QUERY_CAPS) {
        return FALSE;
    }
 
    GstCaps *srcCaps;
    gst_query_parse_caps(query, &srcCaps);
    if (!srcCaps || gst_caps_is_any(srcCaps)) {
        return FALSE;
    }
 
    GstCaps *sinkCaps = nullptr;
    GstCaps *filter = nullptr;
    GstStructure *structure = gst_caps_get_structure(srcCaps, 0);
    if (gst_structure_has_name(structure, "video/x-h265")) {
        filter = gst_caps_from_string("video/x-h265");
        if (gst_caps_can_intersect(srcCaps, filter)) {
            sinkCaps = gst_caps_from_string("video/x-h265,stream-format=hvc1");
        }
        gst_clear_caps(&filter);
    } else if (gst_structure_has_name(structure, "video/x-h264")) {
        filter = gst_caps_from_string("video/x-h264");
        if (gst_caps_can_intersect(srcCaps, filter)) {
            sinkCaps = gst_caps_from_string("video/x-h264,stream-format=avc");
        }
        gst_clear_caps(&filter);
    }
 
    if (sinkCaps) {
        gst_query_set_caps_result(query, sinkCaps);
        gst_clear_caps(&sinkCaps);
        return TRUE;
    }
 
    return FALSE;
}
#endif
 
GstElement *GstVideoReceiver::_makeSource(const QString &input)
{
    if (input.isEmpty()) {
        qCCritical(GstVideoReceiverLog) << "Failed because URI is not specified";
        return nullptr;
    }
 
    const QUrl sourceUrl(input);
 
    const bool isRtsp = sourceUrl.scheme().startsWith("rtsp", Qt::CaseInsensitive);
    const bool isUdp264 = input.contains("udp://", Qt::CaseInsensitive);
    const bool isUdp265 = input.contains("udp265://", Qt::CaseInsensitive);
    const bool isUdpMPEGTS = input.contains("mpegts://", Qt::CaseInsensitive);
    const bool isTcpMPEGTS = input.contains("tcp://", Qt::CaseInsensitive);
 
    GstElement *source = nullptr;
    GstElement *buffer = nullptr;
    GstElement *tsdemux = nullptr;
    GstElement *parser = nullptr;
    GstElement *bin = nullptr;
    GstElement *srcbin = nullptr;
 
    do {
        if (isRtsp) {
            if (!GStreamer::isValidRtspUri(input.toUtf8().constData())) {
                qCCritical(GstVideoReceiverLog) << "Invalid RTSP URI:" << input;
                break;
            }
 
            source = gst_element_factory_make("rtspsrc", "source");
            if (!source) {
                qCCritical(GstVideoReceiverLog) << "gst_element_factory_make('rtspsrc') failed";
                break;
            }
 
            const QString rtspUserInfo = sourceUrl.userInfo();
            QString rtspUser, rtspPassword;
            if (!rtspUserInfo.isEmpty()) {
                const int colonIdx = rtspUserInfo.indexOf(QLatin1Char(':'));
                if (colonIdx >= 0) {
                    rtspUser = rtspUserInfo.left(colonIdx);
                    rtspPassword = rtspUserInfo.mid(colonIdx + 1);
                } else {
                    rtspUser = rtspUserInfo;
                }
            }
            QUrl cleanUrl(sourceUrl);
            cleanUrl.setUserInfo(QString());
            const QByteArray cleanLocation = cleanUrl.toString().toUtf8();
 
            g_object_set(source,
                         "location", cleanLocation.constData(),
                         "latency", 25,
                         "do-rtcp", TRUE,
                         "tcp-timeout", G_GUINT64_CONSTANT(5000000),
                         "udp-reconnect", TRUE,
                         "drop-on-latency", TRUE,
                         "retry", 3,
                         nullptr);
 
            if (!rtspUser.isEmpty()) {
                g_object_set(source,
                             "user-id", rtspUser.toUtf8().constData(),
                             "user-pw", rtspPassword.toUtf8().constData(),
                             nullptr);
            }
        } else if (isTcpMPEGTS) {
            source = gst_element_factory_make("tcpclientsrc", "source");
            if (!source) {
                qCCritical(GstVideoReceiverLog) << "gst_element_factory_make('tcpclientsrc') failed";
                break;
            }
 
            const QString host = sourceUrl.host();
            const quint16 port = sourceUrl.port();
            g_object_set(source,
                         "host", host.toUtf8().constData(),
                         "port", port,
                         nullptr);
        } else if (isUdp264 || isUdp265 || isUdpMPEGTS) {
            source = gst_element_factory_make("udpsrc", "source");
            if (!source) {
                qCCritical(GstVideoReceiverLog) << "gst_element_factory_make('udpsrc') failed";
                break;
            }
 
            const QString uri = QStringLiteral("udp://%1:%2").arg(sourceUrl.host(), QString::number(sourceUrl.port()));
            g_object_set(source,
                         "uri", uri.toUtf8().constData(),
                         "buffer-size", 8 * 1024 * 1024,
                         nullptr);
 
            GstCaps *caps = nullptr;
            if (isUdp264) {
                caps = gst_caps_from_string("application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264");
                if (!caps) {
                    qCCritical(GstVideoReceiverLog) << "gst_caps_from_string() failed";
                    break;
                }
            } else if (isUdp265) {
                caps = gst_caps_from_string("application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H265");
                if (!caps) {
                    qCCritical(GstVideoReceiverLog) << "gst_caps_from_string() failed";
                    break;
                }
            }
 
            if (caps) {
                g_object_set(source,
                             "caps", caps,
                             nullptr);
                gst_clear_caps(&caps);
            }
        } else {
            qCDebug(GstVideoReceiverLog) << "URI is not recognized";
        }
 
        if (!source) {
            qCCritical(GstVideoReceiverLog) << "gst_element_factory_make() for data source failed";
            break;
        }
 
        bin = gst_bin_new("sourcebin");
        if (!bin) {
            qCCritical(GstVideoReceiverLog) << "gst_bin_new('sourcebin') failed";
            break;
        }
 
        parser = gst_element_factory_make("parsebin", "parser");
        if (!parser) {
            qCCritical(GstVideoReceiverLog) << "gst_element_factory_make('parsebin') failed";
            break;
        }
 
        // GStreamer < 1.28: decodebin3 didn't negotiate stream-format caps properly
        // between parser and decoder, so we forced hvc1/avc. GStreamer 1.28+ fixes
        // this natively, and the forced caps break hardware decoders that need
        // byte-stream format (e.g. Qualcomm AMC on Android, D3D12 on Windows).
#if !defined(QGC_GST_BUILD_VERSION_MAJOR) || (QGC_GST_BUILD_VERSION_MAJOR == 1 && QGC_GST_BUILD_VERSION_MINOR < 28)
        (void) g_signal_connect(parser, "autoplug-query", G_CALLBACK(_filterParserCaps), nullptr);
#endif
 
        gst_bin_add_many(GST_BIN(bin), source, parser, nullptr);
 
        // FIXME: AV: Android does not determine MPEG2-TS via parsebin - have to explicitly state which demux to use
        // FIXME: AV: tsdemux handling is a bit ugly - let's try to find elegant solution for that later
        if (isTcpMPEGTS || isUdpMPEGTS) {
            tsdemux = gst_element_factory_make("tsdemux", nullptr);
            if (!tsdemux) {
                qCCritical(GstVideoReceiverLog) << "gst_element_factory_make('tsdemux') failed";
                break;
            }
 
            (void) gst_bin_add(GST_BIN(bin), tsdemux);
 
            if (!gst_element_link(source, tsdemux)) {
                qCCritical(GstVideoReceiverLog) << "gst_element_link() failed";
                break;
            }
 
            source = tsdemux;
            tsdemux = nullptr;
        }
 
        int probeRes = 0;
        (void) gst_element_foreach_src_pad(source, _padProbe, &probeRes);
 
        if (probeRes & 1) {
            if ((probeRes & 2) && (_buffer >= 0)) {
                buffer = gst_element_factory_make("rtpjitterbuffer", nullptr);
                if (!buffer) {
                    qCCritical(GstVideoReceiverLog) << "gst_element_factory_make('rtpjitterbuffer') failed";
                    break;
                }
 
                g_object_set(buffer,
                             "do-lost", TRUE,
                             "drop-on-latency", _buffer == 0 ? TRUE : FALSE,
                             nullptr);
 
                (void) gst_bin_add(GST_BIN(bin), buffer);
 
                if (!gst_element_link_many(source, buffer, parser, nullptr)) {
                    qCCritical(GstVideoReceiverLog) << "gst_element_link() failed";
                    break;
                }
            } else {
                if (!gst_element_link(source, parser)) {
                    qCCritical(GstVideoReceiverLog) << "gst_element_link() failed";
                    break;
                }
            }
        } else {
            (void) g_signal_connect(source, "pad-added", G_CALLBACK(_linkPad), parser);
        }
 
        (void) g_signal_connect(parser, "pad-added", G_CALLBACK(_wrapWithGhostPad), nullptr);
 
        source = tsdemux = buffer = parser = nullptr;
 
        srcbin = bin;
        bin = nullptr;
    } while(0);
 
    gst_clear_object(&bin);
    gst_clear_object(&parser);
    gst_clear_object(&tsdemux);
    gst_clear_object(&buffer);
    gst_clear_object(&source);
 
    return srcbin;
}
 
GstElement *GstVideoReceiver::_makeDecoder()
{
    GstElement *decoder = gst_element_factory_make("decodebin3", nullptr);
    if (!decoder) {
        qCCritical(GstVideoReceiverLog) << "gst_element_factory_make('decodebin3') failed";
    }
    return decoder;
}
 
GstElement *GstVideoReceiver::_makeFileSink(const QString &videoFile, FILE_FORMAT format)
{
    GstElement *fileSink = nullptr;
    GstElement *mux = nullptr;
    GstElement *sink = nullptr;
    GstElement *bin = nullptr;
    bool releaseElements = true;
 
    do {
        if (!isValidFileFormat(format)) {
            qCCritical(GstVideoReceiverLog) << "Unsupported file format";
            break;
        }
 
        mux = gst_element_factory_make(_kFileMux[format], nullptr);
        if (!mux) {
            qCCritical(GstVideoReceiverLog) << "gst_element_factory_make('" << _kFileMux[format] << "') failed";
            break;
        }
 
        // mp4mux/qtmux: write moov atom up-front + reserve space for index updates so a crash
        // mid-recording leaves a playable file. matroskamux is naturally streamable; skip.
        if (format == FILE_FORMAT_MP4 || format == FILE_FORMAT_MOV) {
            g_object_set(mux,
                         "faststart", TRUE,
                         "reserved-moov-update-period", G_GUINT64_CONSTANT(1000000000),
                         nullptr);
        }
 
        sink = gst_element_factory_make("filesink", nullptr);
        if (!sink) {
            qCCritical(GstVideoReceiverLog) << "gst_element_factory_make('filesink') failed";
            break;
        }
 
        g_object_set(sink,
                     "location", qPrintable(videoFile),
                     nullptr);
 
        bin = gst_bin_new("sinkbin");
        if (!bin) {
            qCCritical(GstVideoReceiverLog) << "gst_bin_new('sinkbin') failed";
            break;
        }
 
        GstPadTemplate *padTemplate = gst_element_class_get_pad_template(GST_ELEMENT_GET_CLASS(mux), "video_%u");
        if (!padTemplate) {
            qCCritical(GstVideoReceiverLog) << "gst_element_class_get_pad_template(mux) failed";
            break;
        }
 
        // FIXME: pad handling is potentially leaking (and other similar places too!)
        GstPad *pad = gst_element_request_pad(mux, padTemplate, nullptr, nullptr);
        if (!pad) {
            qCCritical(GstVideoReceiverLog) << "gst_element_request_pad(mux) failed";
            break;
        }
 
        gst_bin_add_many(GST_BIN(bin), mux, sink, nullptr);
 
        releaseElements = false;
 
        GstPad *ghostpad = gst_ghost_pad_new("sink", pad);
        (void) gst_element_add_pad(bin, ghostpad);
        gst_clear_object(&pad);
 
        if (!gst_element_link(mux, sink)) {
            qCCritical(GstVideoReceiverLog) << "gst_element_link() failed";
            break;
        }
 
        fileSink = bin;
        bin = nullptr;
    } while(0);
 
    if (releaseElements) {
        gst_clear_object(&sink);
        gst_clear_object(&mux);
    }
 
    gst_clear_object(&bin);
    return fileSink;
}
 
void GstVideoReceiver::_onNewSourcePad(GstPad *pad)
{
    // FIXME: check for caps - if this is not video stream (and preferably - one of these which we have to support) then simply skip it
    if (!gst_element_link(_source, _tee)) {
        qCCritical(GstVideoReceiverLog) << "Unable to link source";
        return;
    }
 
    if (!_streaming) {
        _streaming = true;
        qCDebug(GstVideoReceiverLog) << "Streaming started" << _uri;
        _dispatchSignal([this]() { emit streamingChanged(_streaming); });
    }
 
    _eosProbeId = gst_pad_add_probe(pad, GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM, _eosProbe, this, nullptr);
    if (_eosProbeId != 0) {
        // Hold a ref so _shutdownDecodingBranch can remove the probe even after _decoder is gone.
        _eosProbePad = GST_PAD_CAST(gst_object_ref(pad));
    }
    if (!_videoSink) {
        return;
    }
 
    GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(_pipeline), GST_DEBUG_GRAPH_SHOW_ALL, "pipeline-with-new-source-pad");
 
    _ensureVideoSinkInPipeline();
 
    if (!_addDecoder(_decoderValve)) {
        qCCritical(GstVideoReceiverLog) << "_addDecoder() failed";
        _shutdownDecodingBranch();
        return;
    }
 
    g_object_set(_decoderValve,
                 "drop", FALSE,
                 nullptr);
 
    qCDebug(GstVideoReceiverLog) << "Decoding started" << _uri;
}
 
void GstVideoReceiver::_logDecodebin3SelectedCodec(GstElement *decodebin3)
{
    GValue value = G_VALUE_INIT;
    GstIterator *iter = gst_bin_iterate_elements(GST_BIN(decodebin3));
    GstElement *child;
 
    while (gst_iterator_next(iter, &value) == GST_ITERATOR_OK) {
        child = GST_ELEMENT(g_value_get_object(&value));
        GstElementFactory *factory = gst_element_get_factory(child);
 
        if (factory) {
            gboolean is_decoder = gst_element_factory_list_is_type(factory, GST_ELEMENT_FACTORY_TYPE_DECODER);
            if (is_decoder) {
                const gchar *decoderKlass = gst_element_factory_get_klass(factory);
                GstPluginFeature *feature = GST_PLUGIN_FEATURE(factory);
                const gchar *featureName = gst_plugin_feature_get_name(feature);
                const guint rank = gst_plugin_feature_get_rank(feature);
                bool isHardwareDecoder = GStreamer::isHardwareDecoderFactory(factory);
 
                QString pluginName = featureName;
                GstPlugin *plugin = gst_plugin_feature_get_plugin(feature);
                if (plugin) {
                    pluginName = gst_plugin_get_name(plugin);
                    gst_object_unref(plugin);
                }
                qCDebug(GstVideoReceiverLog) << "Decodebin3 selected codec:rank -" << pluginName << "/" << featureName << "-" << decoderKlass << (isHardwareDecoder ? "(HW)" : "(SW)") << ":" << rank;
 
                const QString newName = QString::fromUtf8(featureName);
                if (newName != _decoderName) {
                    _decoderName = newName;
                    _dispatchSignal([this]() { emit decoderStatsChanged(); });
                }
 
                // Disable QoS on the internal decoder to prevent cascading
                // frame drops on live streams.  The videodecoder base class
                // aggressively advances earliest_time after the first late
                // frame, causing all subsequent frames to be dropped.
                g_object_set(child, "qos", FALSE, nullptr);
                qCDebug(GstVideoReceiverLog) << "Disabled QoS on internal decoder" << featureName;
            }
        }
        g_value_reset(&value);
    }
    g_value_unset(&value);
    gst_iterator_free(iter);
}
 
 
void GstVideoReceiver::_onNewDecoderPad(GstPad *pad)
{
    qCDebug(GstVideoReceiverLog) << "_onNewDecoderPad" << _uri;
 
    GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(_pipeline), GST_DEBUG_GRAPH_SHOW_ALL, "pipeline-with-new-decoder-pad");
 
    // We should now know what codec decodebin3 selected.
    _logDecodebin3SelectedCodec(_decoder);
 
    if (!_addVideoSink(pad)) {
        qCCritical(GstVideoReceiverLog) << "_addVideoSink() failed";
    }
}
 
bool GstVideoReceiver::_addDecoder(GstElement *src)
{
    _decoder = _makeDecoder();
    if (!_decoder) {
        qCCritical(GstVideoReceiverLog) << "_makeDecoder() failed";
        return false;
    }
 
    (void) gst_object_ref(_decoder);
 
    (void) gst_bin_add(GST_BIN(_pipeline), _decoder);
    (void) gst_element_sync_state_with_parent(_decoder);
 
    GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(_pipeline), GST_DEBUG_GRAPH_SHOW_ALL, "pipeline-with-decoder");
 
    if (!gst_element_link(src, _decoder)) {
        qCCritical(GstVideoReceiverLog) << "Unable to link decoder";
        gst_element_set_state(_decoder, GST_STATE_NULL);
        (void) gst_element_get_state(_decoder, nullptr, nullptr, GST_CLOCK_TIME_NONE);
        (void) gst_bin_remove(GST_BIN(_pipeline), _decoder);
        gst_clear_object(&_decoder);
        return false;
    }
 
    GstPad *srcPad = nullptr;
    GstIterator *it = gst_element_iterate_src_pads(_decoder);
    GValue vpad = G_VALUE_INIT;
    switch (gst_iterator_next(it, &vpad)) {
        case GST_ITERATOR_OK:
            srcPad = GST_PAD(g_value_get_object(&vpad));
            (void) gst_object_ref(srcPad);
            (void) g_value_reset(&vpad);
            break;
        case GST_ITERATOR_RESYNC:
            gst_iterator_resync(it);
            break;
        default:
            break;
    }
    g_value_unset(&vpad);
    gst_iterator_free(it);
 
    if (srcPad) {
        _onNewDecoderPad(srcPad);
    } else {
        (void) g_signal_connect(_decoder, "pad-added", G_CALLBACK(_onNewPad), this);
    }
 
    gst_clear_object(&srcPad);
    return true;
}
 
void GstVideoReceiver::_ensureVideoSinkInPipeline()
{
    if (!_videoSink || !_pipeline) {
        return;
    }
 
    GstObject *parent = gst_element_get_parent(_videoSink);
    if (parent) {
        gst_object_unref(parent);
        return;
    }
 
    g_object_set(_videoSink,
                 "sync", (_buffer >= 0),
                 NULL);
 
    (void) gst_object_ref(_videoSink);
    (void) gst_bin_add(GST_BIN(_pipeline), _videoSink);
 
    // PAUSED (not READY) triggers downstream caps negotiation before source data arrives.
    (void) gst_element_set_state(_videoSink, GST_STATE_PAUSED);
}
 
bool GstVideoReceiver::_addVideoSink(GstPad *pad)
{
    GstCaps *caps = gst_pad_query_caps(pad, nullptr);
 
    _ensureVideoSinkInPipeline();
 
    GstPad *sinkPad = gst_element_get_static_pad(_videoSink, "sink");
    GstPadLinkReturn linkRet = sinkPad ? gst_pad_link(pad, sinkPad) : GST_PAD_LINK_WRONG_HIERARCHY;
    if (linkRet != GST_PAD_LINK_OK) {
        qCCritical(GstVideoReceiverLog) << "Unable to link decoder pad to video sink, result:" << linkRet;
 
        // _ensureVideoSinkInPipeline() added it before linking; detach for the next retry.
        GstObject *parent = gst_element_get_parent(_videoSink);
        if (parent) {
            (void) gst_element_set_state(_videoSink, GST_STATE_NULL);
            (void) gst_element_get_state(_videoSink, nullptr, nullptr, GST_CLOCK_TIME_NONE);
            (void) gst_bin_remove(GST_BIN(_pipeline), _videoSink);
            gst_clear_object(&parent);
        }
 
        gst_clear_object(&sinkPad);
        gst_clear_caps(&caps);
        return false;
    }
    gst_clear_object(&sinkPad);
 
    (void) gst_element_sync_state_with_parent(_videoSink);
 
    // sync=FALSE + max-lateness=-1: HW decoders with startup latency must not drop early frames.
    g_object_set(_videoSink, "sync", FALSE, "max-lateness", G_GINT64_CONSTANT(-1), nullptr);
 
    GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(_pipeline), GST_DEBUG_GRAPH_SHOW_ALL, "pipeline-with-videosink");
 
    // Determine video size. Errors here are non-fatal.
    QSize videoSize;
    do {
        if (!_decoderValve) {
            qCCritical(GstVideoReceiverLog) << "Unable to determine video size - _decoderValve is NULL" << _uri;
            break;
        }
 
        GstPad *valveSrcPad = gst_element_get_static_pad(_decoderValve, "src");
        if (!valveSrcPad) {
            qCCritical(GstVideoReceiverLog) << "gst_element_get_static_pad() failed";
            break;
        }
 
        GstCaps *valveSrcPadCaps = gst_pad_query_caps(valveSrcPad, nullptr);
        if (!valveSrcPadCaps) {
            qCCritical(GstVideoReceiverLog) << "gst_pad_query_caps() failed";
            gst_clear_object(&valveSrcPad);
            break;
        }
 
        const GstStructure *structure = gst_caps_get_structure(valveSrcPadCaps, 0);
        if (!structure) {
            qCCritical(GstVideoReceiverLog) << "Unable to determine video size - structure is NULL" << _uri;
            gst_clear_object(&valveSrcPad);
            break;
        }
 
        gint width = 0;
        gint height = 0;
        (void) gst_structure_get_int(structure, "width", &width);
        (void) gst_structure_get_int(structure, "height", &height);
 
        // Swap W×H for 90°/270° streams so QML AR is computed on display dimensions.
        gint orientation = 0;
        if (gst_structure_get_int(structure, "video-orientation", &orientation)
            && (orientation == GST_VIDEO_ORIENTATION_90R
                || orientation == GST_VIDEO_ORIENTATION_90L
                || orientation == GST_VIDEO_ORIENTATION_UL_LR
                || orientation == GST_VIDEO_ORIENTATION_UR_LL)) {
            videoSize.setWidth(height);
            videoSize.setHeight(width);
        } else {
            videoSize.setWidth(width);
            videoSize.setHeight(height);
        }
 
        gst_clear_caps(&valveSrcPadCaps);
        gst_clear_object(&valveSrcPad);
    } while (false);
    _dispatchSignal([this, videoSize]() { emit videoSizeChanged(videoSize); });
 
    gst_clear_caps(&caps);
    return true;
}
 
void GstVideoReceiver::_noteTeeFrame()
{
    _lastSourceFrameTime = QDateTime::currentSecsSinceEpoch();
}
 
void GstVideoReceiver::_noteVideoSinkFrame()
{
    _lastVideoFrameTime = QDateTime::currentSecsSinceEpoch();
    if (!_decoding) {
        _decoding = true;
        qCDebug(GstVideoReceiverLog) << "Decoding started";
        _dispatchSignal([this]() { emit decodingChanged(_decoding); });
    }
}
 
void GstVideoReceiver::_noteEndOfStream()
{
    _endOfStream = true;
}
 
bool GstVideoReceiver::_unlinkBranch(GstElement *from)
{
    GstPad *src = gst_element_get_static_pad(from, "src");
    if (!src) {
        qCCritical(GstVideoReceiverLog) << "gst_element_get_static_pad() failed";
        return false;
    }
 
    GstPad *sink = gst_pad_get_peer(src);
    if (!sink) {
        gst_clear_object(&src);
        qCCritical(GstVideoReceiverLog) << "gst_pad_get_peer() failed";
        return false;
    }
 
    if (!gst_pad_unlink(src, sink)) {
        gst_clear_object(&src);
        gst_clear_object(&sink);
        qCCritical(GstVideoReceiverLog) << "gst_pad_unlink() failed";
        return false;
    }
 
    gst_clear_object(&src);
 
    // Send EOS at the beginning of the branch
    const gboolean ret = gst_pad_send_event(sink, gst_event_new_eos());
 
    gst_clear_object(&sink);
 
    if (!ret) {
        qCCritical(GstVideoReceiverLog) << "Branch EOS was NOT sent";
        return false;
    }
 
    qCDebug(GstVideoReceiverLog) << "Branch EOS was sent";
 
    return true;
}
 
void GstVideoReceiver::_shutdownDecodingBranch()
{
    if (_decoder) {
        GstObject *parent = gst_element_get_parent(_decoder);
        if (parent) {
            (void) gst_bin_remove(GST_BIN(_pipeline), _decoder);
            (void) gst_element_set_state(_decoder, GST_STATE_NULL);
            (void) gst_element_get_state(_decoder, nullptr, nullptr, GST_CLOCK_TIME_NONE);
            gst_clear_object(&parent);
        }
 
        gst_clear_object(&_decoder);
    }
 
    if (_videoSinkProbeId != 0 && _videoSink) {
        GstPad *sinkpad = gst_element_get_static_pad(_videoSink, "sink");
        if (sinkpad) {
            gst_pad_remove_probe(sinkpad, _videoSinkProbeId);
            gst_clear_object(&sinkpad);
        }
    }
    _videoSinkProbeId = 0;
 
    if (_eosProbeId != 0 && _eosProbePad) {
        // Probe was installed on the source pad in _onNewSourcePad; remove from that exact pad — not from _decoder, which may already be cleared above.
        gst_pad_remove_probe(_eosProbePad, _eosProbeId);
    }
    _eosProbeId = 0;
    gst_clear_object(&_eosProbePad);
 
    _lastVideoFrameTime = 0;
 
    if (_videoSink) {
        GstObject *parent = gst_element_get_parent(_videoSink);
        if (parent) {
            (void) gst_bin_remove(GST_BIN(_pipeline), _videoSink);
            (void) gst_element_set_state(_videoSink, GST_STATE_NULL);
            (void) gst_element_get_state(_videoSink, nullptr, nullptr, GST_CLOCK_TIME_NONE);
            gst_clear_object(&parent);
        }
        gst_clear_object(&_videoSink);
    }
 
    _removingDecoder = false;
 
    if (_decoding) {
        _decoding = false;
        qCDebug(GstVideoReceiverLog) << "Decoding stopped";
        _dispatchSignal([this]() { emit decodingChanged(_decoding); });
    }
 
    GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(_pipeline), GST_DEBUG_GRAPH_SHOW_ALL, "pipeline-decoding-stopped");
}
 
void GstVideoReceiver::_shutdownRecordingBranch()
{
    if (_keyframeWatchId != 0 && _recorderValve) {
        GstPad *probepad = gst_element_get_static_pad(_recorderValve, "src");
        if (probepad) {
            gst_pad_remove_probe(probepad, _keyframeWatchId);
            gst_clear_object(&probepad);
        }
        _keyframeWatchId = 0;
    }
 
    gst_bin_remove(GST_BIN(_pipeline), _fileSink);
    gst_element_set_state(_fileSink, GST_STATE_NULL);
    (void) gst_element_get_state(_fileSink, nullptr, nullptr, GST_CLOCK_TIME_NONE);
    gst_clear_object(&_fileSink);
 
    _removingRecorder = false;
 
    if (_recording) {
        _recording = false;
        qCDebug(GstVideoReceiverLog) << "Recording stopped";
        _dispatchSignal([this]() { emit recordingChanged(_recording); });
    }
 
    if (_recordingStopRequested) {
        _recordingStopRequested = false;
        _dispatchSignal([this]() { emit onStopRecordingComplete(STATUS_OK); });
    }
 
    GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(_pipeline), GST_DEBUG_GRAPH_SHOW_ALL, "pipeline-recording-stopped");
}
 
bool GstVideoReceiver::_needDispatch()
{
    return _worker->needDispatch();
}
 
void GstVideoReceiver::_dispatchSignal(Task emitter)
{
    _signalDepth += 1;
    emitter();
    _signalDepth -= 1;
}
 
gboolean GstVideoReceiver::_onBusMessage(GstBus * /* bus */, GstMessage *msg, gpointer data)
{
    if (!msg || !data) {
        qCCritical(GstVideoReceiverLog) << "Invalid parameters in _onBusMessage: msg=" << msg << "data=" << data;
        return TRUE;
    }
 
    GstVideoReceiver *pThis = static_cast<GstVideoReceiver*>(data);
 
    switch (GST_MESSAGE_TYPE(msg)) {
    case GST_MESSAGE_ERROR: {
        gchar *debug;
        GError *error;
        gst_message_parse_error(msg, &error, &debug);
 
        if (debug) {
            qCDebug(GstVideoReceiverLog) << "GStreamer debug:" << debug;
            g_clear_pointer(&debug, g_free);
        }
 
        if (error) {
            qCCritical(GstVideoReceiverLog) << "GStreamer error:" << error->message;
            g_clear_error(&error);
        }
 
        if (pThis->_pipeline) {
            GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(pThis->_pipeline), GST_DEBUG_GRAPH_SHOW_ALL, "pipeline-error");
        }
 
#if defined(QGC_HAS_GST_GLMEMORY_GPU_PATH) || defined(QGC_HAS_GST_D3D11_GPU_PATH) || defined(QGC_HAS_GST_D3D12_GPU_PATH)
        // Drop bridge-cached devices defensively. D3D11/D3D12 errors are most often device-loss
        // (DXGI_ERROR_DEVICE_REMOVED on driver reset / TDR / GPU detach); GST_MESSAGE_ERROR
        // doesn't carry a structured device-lost code, so reset on any error rather than
        // letting the next pipeline restart re-use a potentially-dead cached device. Cost on
        // false positives is one device re-discovery on next prime — already paid on cold start.
        // Render-thread mapTextures calls currentDevice() with transfer-full ownership now,
        // so an in-flight mapTextures keeps its own ref alive across this reset.
        GstContextBridgeRegistry::resetAllBridges();
#endif
 
        pThis->_worker->dispatch([pThis]() {
            qCDebug(GstVideoReceiverLog) << "Stopping because of error";
            pThis->stop();
        });
        break;
    }
    case GST_MESSAGE_WARNING: {
        // GStreamer posts WARNING for caps mismatches, decoder fallbacks, clock drift —
        // surfacing keeps these visible without escalating to STATUS_FAIL.
        gchar *debug = nullptr;
        GError *error = nullptr;
        gst_message_parse_warning(msg, &error, &debug);
        qCWarning(GstVideoReceiverLog) << "GStreamer warning:"
                                       << (error ? error->message : "(no message)")
                                       << "debug:" << (debug ? debug : "(none)");
        g_clear_error(&error);
        g_clear_pointer(&debug, g_free);
        break;
    }
    case GST_MESSAGE_EOS:
        pThis->_worker->dispatch([pThis]() {
            qCDebug(GstVideoReceiverLog) << "Received EOS";
            pThis->_handleEOS();
        });
        break;
    case GST_MESSAGE_STREAM_COLLECTION: {
        GstStreamCollection *collection = nullptr;
        gst_message_parse_stream_collection(msg, &collection);
        if (!collection) {
            break;
        }
        // SELECT_STREAMS keeps decodebin3 from instantiating audio decoder branches.
        GList *selectedIds = nullptr;
        const guint nStreams = gst_stream_collection_get_size(collection);
        for (guint i = 0; i < nStreams; ++i) {
            GstStream *stream = gst_stream_collection_get_stream(collection, i);
            const GstStreamType type = gst_stream_get_stream_type(stream);
            if (type & GST_STREAM_TYPE_VIDEO) {
                selectedIds = g_list_append(selectedIds,
                    g_strdup(gst_stream_get_stream_id(stream)));
            }
        }
        if (selectedIds) {
            GstEvent *event = gst_event_new_select_streams(selectedIds);
            gst_element_send_event(GST_ELEMENT(GST_MESSAGE_SRC(msg)), event);
            g_list_free_full(selectedIds, g_free);
        }
        gst_object_unref(collection);
        break;
    }
    case GST_MESSAGE_QOS: {
        guint64 processed = 0, dropped = 0;
        gst_message_parse_qos_stats(msg, nullptr, &processed, &dropped);
 
        gint64 jitter = 0;
        gdouble proportion = 0;
        gint quality = 0;
        gst_message_parse_qos_values(msg, &jitter, &proportion, &quality);
 
        pThis->_processedFrames = processed;
        pThis->_droppedFrames = dropped;
        pThis->_currentJitterNs = jitter;
        pThis->_qosProportion = proportion;
        pThis->_qosQuality = quality;
        pThis->_dispatchSignal([pThis]() { emit pThis->decoderStatsChanged(); });
        break;
    }
    case GST_MESSAGE_ELEMENT: {
        const GstStructure *structure = gst_message_get_structure(msg);
        if (!gst_structure_has_name(structure, "GstBinForwarded")) {
            break;
        }
 
        GstMessage *forward_msg = nullptr;
        gst_structure_get(structure, "message", GST_TYPE_MESSAGE, &forward_msg, NULL);
        if (!forward_msg) {
            break;
        }
 
        if (GST_MESSAGE_TYPE(forward_msg) == GST_MESSAGE_EOS) {
            pThis->_worker->dispatch([pThis]() {
                qCDebug(GstVideoReceiverLog) << "Received branch EOS";
                pThis->_handleEOS();
            });
        }
 
        gst_clear_message(&forward_msg);
        break;
    }
    case GST_MESSAGE_STATE_CHANGED: {
        if (GST_MESSAGE_SRC(msg) != GST_OBJECT(pThis->_pipeline)) {
            break;
        }
        GstState oldState = GST_STATE_NULL, newState = GST_STATE_NULL;
        gst_message_parse_state_changed(msg, &oldState, &newState, nullptr);
        if (newState == GST_STATE_PLAYING && oldState != GST_STATE_PLAYING) {
            GstClockTime min = 0, max = 0;
            GstQuery *q = gst_query_new_latency();
            if (gst_element_query(pThis->_pipeline, q)) {
                gboolean live = FALSE;
                gst_query_parse_latency(q, &live, &min, &max);
            }
            gst_query_unref(q);
            qCDebug(GstVideoReceiverLog).noquote()
                << "Pipeline PLAYING:" << pThis->_uri
                << "decoder:" << (pThis->_decoderName.isEmpty() ? QStringLiteral("(pending)") : pThis->_decoderName)
                << "min-latency:" << (min / 1000000) << "ms"
                << "max-latency:" << (max / 1000000) << "ms";
        }
        break;
    }
    case GST_MESSAGE_LATENCY:
        pThis->_worker->dispatch([pThis]() {
            if (pThis->_pipeline) {
                (void) gst_bin_recalculate_latency(GST_BIN(pThis->_pipeline));
            }
        });
        pThis->_dispatchSignal([pThis]() { emit pThis->latencyChanged(); });
        break;
    default:
        break;
    }
 
    return TRUE;
}
 
void GstVideoReceiver::_onNewPad(GstElement *element, GstPad *pad, gpointer data)
{
    GstVideoReceiver *self = static_cast<GstVideoReceiver*>(data);
 
    if (element == self->_source) {
        self->_onNewSourcePad(pad);
    } else if (element == self->_decoder) {
        self->_onNewDecoderPad(pad);
    } else {
        qCDebug(GstVideoReceiverLog) << "Unexpected call!";
    }
}
 
void GstVideoReceiver::_wrapWithGhostPad(GstElement *element, GstPad *pad, gpointer data)
{
    Q_UNUSED(data)
 
    gchar *name = gst_pad_get_name(pad);
    if (!name) {
        qCCritical(GstVideoReceiverLog) << "gst_pad_get_name() failed";
        return;
    }
 
    GstPad *ghostpad = gst_ghost_pad_new(name, pad);
    if (!ghostpad) {
        qCCritical(GstVideoReceiverLog) << "gst_ghost_pad_new() failed";
        g_clear_pointer(&name, g_free);
        return;
    }
 
    g_clear_pointer(&name, g_free);
 
    (void) gst_pad_set_active(ghostpad, TRUE);
 
    if (!gst_element_add_pad(GST_ELEMENT_PARENT(element), ghostpad)) {
        qCCritical(GstVideoReceiverLog) << "gst_element_add_pad() failed";
    }
}
 
void GstVideoReceiver::_linkPad(GstElement *element, GstPad *pad, gpointer data)
{
    gchar *name = gst_pad_get_name(pad);
    if (!name) {
        qCCritical(GstVideoReceiverLog) << "gst_pad_get_name() failed";
        return;
    }
 
    if (!gst_element_link_pads(element, name, GST_ELEMENT(data), "sink")) {
        qCCritical(GstVideoReceiverLog) << "gst_element_link_pads() failed";
    }
 
    g_clear_pointer(&name, g_free);
}
 
gboolean GstVideoReceiver::_padProbe(GstElement *element, GstPad *pad, gpointer user_data)
{
    Q_UNUSED(element)
 
    int *probeRes = static_cast<int*>(user_data);
    *probeRes |= 1;
 
    GstCaps *filter = gst_caps_from_string("application/x-rtp");
    if (filter) {
        GstCaps *caps = gst_pad_query_caps(pad, nullptr);
        if (caps) {
            if (!gst_caps_is_any(caps) && gst_caps_can_intersect(caps, filter)) {
                *probeRes |= 2;
            }
 
            gst_clear_caps(&caps);
        }
 
        gst_clear_caps(&filter);
    }
 
    return TRUE;
}
 
GstPadProbeReturn GstVideoReceiver::_teeProbe(GstPad *pad, GstPadProbeInfo *info, gpointer user_data)
{
    Q_UNUSED(pad); Q_UNUSED(info)
 
    if (user_data) {
        GstVideoReceiver *pThis = static_cast<GstVideoReceiver*>(user_data);
        pThis->_noteTeeFrame();
    }
 
    return GST_PAD_PROBE_OK;
}
 
GstPadProbeReturn GstVideoReceiver::_videoSinkProbe(GstPad *pad, GstPadProbeInfo *info, gpointer user_data)
{
    Q_UNUSED(pad); Q_UNUSED(info)
 
    if (user_data) {
        GstVideoReceiver *pThis = static_cast<GstVideoReceiver*>(user_data);
 
        if (pThis->_resetVideoSink) {
            pThis->_resetVideoSink = false;
 
#if 0 // FIXME: this makes MPEG2-TS playing smooth but breaks RTSP
           gst_pad_send_event(pad, gst_event_new_flush_start());
           gst_pad_send_event(pad, gst_event_new_flush_stop(TRUE));
 
           GstBuffer* buf;
 
           if ((buf = gst_pad_probe_info_get_buffer(info)) != nullptr) {
               GstSegment* seg;
 
               if ((seg = gst_segment_new()) != nullptr) {
                   gst_segment_init(seg, GST_FORMAT_TIME);
 
                   seg->start = buf->pts;
 
                   gst_pad_send_event(pad, gst_event_new_segment(seg));
 
                   gst_segment_free(seg);
                   seg = nullptr;
               }
 
               gst_pad_set_offset(pad, -static_cast<gint64>(buf->pts));
           }
#endif
        }
 
        pThis->_noteVideoSinkFrame();
    }
 
    return GST_PAD_PROBE_OK;
}
 
GstPadProbeReturn GstVideoReceiver::_eosProbe(GstPad *pad, GstPadProbeInfo *info, gpointer user_data)
{
    Q_UNUSED(pad);
    Q_ASSERT(user_data);
 
    if (info) {
        const GstEvent *event = gst_pad_probe_info_get_event(info);
        if (GST_EVENT_TYPE(event) == GST_EVENT_EOS) {
            GstVideoReceiver *pThis = static_cast<GstVideoReceiver*>(user_data);
            pThis->_noteEndOfStream();
        }
    }
 
    return GST_PAD_PROBE_OK;
}
 
GstPadProbeReturn GstVideoReceiver::_keyframeWatch(GstPad *pad, GstPadProbeInfo *info, gpointer user_data)
{
    if (!info || !user_data) {
        qCCritical(GstVideoReceiverLog) << "Invalid arguments";
        return GST_PAD_PROBE_DROP;
    }
 
    GstBuffer *buf = gst_pad_probe_info_get_buffer(info);
    if (GST_BUFFER_FLAG_IS_SET(buf, GST_BUFFER_FLAG_DELTA_UNIT)) {
        // wait for a keyframe
        return GST_PAD_PROBE_DROP;
    }
 
    // set media file '0' offset to current timeline position - we don't want to touch other elements in the graph, except these which are downstream!
    gst_pad_set_offset(pad, -static_cast<gint64>(buf->pts));
 
    qCDebug(GstVideoReceiverLog) << "Got keyframe, stop dropping buffers";
 
    GstVideoReceiver *pThis = static_cast<GstVideoReceiver*>(user_data);
    pThis->_dispatchSignal([pThis]() { emit pThis->recordingStarted(pThis->recordingOutput()); });
 
    return GST_PAD_PROBE_REMOVE;
}
 
GstVideoWorker::GstVideoWorker(QObject *parent)
    : QThread(parent)
{
    qCDebug(GstVideoReceiverLog) << this;
}
 
GstVideoWorker::~GstVideoWorker()
{
    qCDebug(GstVideoReceiverLog) << this;
}
 
bool GstVideoWorker::needDispatch() const
{
    return (QThread::currentThread() != this);
}
 
void GstVideoWorker::dispatch(Task task)
{
    QMutexLocker lock(&_taskQueueSync);
    _taskQueue.enqueue(task);
    _taskQueueUpdate.wakeOne();
}
 
void GstVideoWorker::shutdown()
{
    if (needDispatch()) {
        dispatch([this]() { _shutdown = true; });
        (void) QThread::wait(2000);
    } else {
        QThread::quit();
    }
}
 
void GstVideoWorker::run()
{
    while (!_shutdown) {
        _taskQueueSync.lock();
 
        while (_taskQueue.isEmpty()) {
            _taskQueueUpdate.wait(&_taskQueueSync);
        }
 
        const Task task = _taskQueue.dequeue();
 
        _taskQueueSync.unlock();
 
        task();
    }
}