Gstreamer using tee and valve element for recording and displaying

Application Development Embedded
1

Hello, I create a pipeline with parse launch, I have a bit tee structure on it and I have a recorder structure that starts at the beginning while showing my broadcast with videosink and I have a button on the qml side, I trigger the stoprecording function here, but whenever I trigger it, the image in the videosink structure freezes and stops flowing while the file is being recorded, I have tried many methods, when I give the eosu to the filesink, my whole application freezes when I press the stop button, I need help because I am new to gstreamer, thanks in advance. @Joe

 QString pipelineDescription = QString(
                                      "rtspsrc location=%1 latency=0 udp-reconnect=1 ! "
                                      "rtpjitterbuffer latency=50 ! "
                                      "rtph264depay ! "
                                      "h264parse ! "
                                      "avdec_h264 ! "
                                      "videoconvert ! "
                                      "tee name=t "

                                      "t. ! queue ! "
                                      "glupload ! "
                                      "glcolorconvert ! "
                                      "qmlglsink name=video_sink "

                                      "t. ! queue ! "
                                      "valve name =recording_valve ! "
                                      "videoconvert ! "
                                      "video/x-raw,format=I420 ! "
                                      "x264enc tune=zerolatency ! "
                                      "mp4mux ! "
                                      "filesink name= file_sink location=/home/user/stream_record.mp4"
                                      ).arg(url);

    GError *error = nullptr;
    pipeline = gst_parse_launch(qPrintable(pipelineDescription), &error);
    if (!pipeline || error) {
        qCritical() << "Failed to create pipeline:" << (error ? error->message : "unknown error");
        if (error) g_error_free(error);
        return;
    }

    GstElement *videoSink = gst_bin_get_by_name(GST_BIN(pipeline), "video_sink");
    if (!videoSink) {
        qCritical() << "Failed to find qmlglsink in pipeline.";
        gst_object_unref(pipeline);
        pipeline = nullptr;
        return;
    }

    g_object_set(G_OBJECT(videoSink), "widget", videoItem, nullptr);
    gst_object_unref(videoSink);

    GstBus *bus = gst_element_get_bus(pipeline);
    gst_bus_add_watch(bus, (GstBusFunc)GStreamerQmlSink::busCall, this);
    gst_object_unref(bus);

    GstStateChangeReturn ret = gst_element_set_state(pipeline, GST_STATE_PLAYING);
    if (ret == GST_STATE_CHANGE_FAILURE) {
        qCritical() << "Failed to set pipeline to PLAYING.";
        gst_object_unref(pipeline);
        pipeline = nullptr;
        return;
    }

    qInfo() << "Pipeline started successfully.";
}

    void GStreamerQmlSink::stopRecording()
    {
        if (!pipeline) {
            qWarning() << "No active pipeline.";
            return;
        }
    
        GstElement *fileSink = gst_bin_get_by_name(GST_BIN(pipeline), "file_sink");
        if (!fileSink) {
            qWarning() << "No active recording found.";
            return;
        }
    
        qInfo() << "Stopping recording...";
    
       
        GstEvent *eos_event = gst_event_new_eos();
        gst_element_send_event(pipeline, eos_event);
    
        
        GstBus *bus = gst_element_get_bus(pipeline);
        GstMessage *msg = gst_bus_timed_pop_filtered(bus, GST_CLOCK_TIME_NONE, GST_MESSAGE_EOS);
        if (msg)
            gst_message_unref(msg);
        gst_object_unref(bus);
    
        
        gst_element_set_state(fileSink, GST_STATE_NULL);
        qInfo() << "Recording stopped successfully. MP4 file is now valid.";
    }
2

Can you try to send eos event to the recording queue instead of file sink?

3

yes, after sending eos signal to queue or decoder elements, I make filesink element null and this works. Thank you Joe. Since I am new to Gstreamer, I am trying to proceed step by step. I want to start and stop recording by adding a valve element to the record branch and create the necessary additions and functions. First, I give TRUE to the valve element for recorder so that the broadcast part does not start, but when I do this, the image shows the first frame. In this case, how should I use a valve?

void GStreamerQmlSink::startStream(const QString &url, QQuickItem *videoItem)
{
    if (pipeline) {
        qWarning() << "Stream already running.";
        return;
    }
    videoItemRef = videoItem;
// "watchdog timeout=10000 ! "
    QString pipelineDescription = QString(
                                      "rtspsrc location=%1 latency=0 udp-reconnect=1 ! "
                                      "rtpjitterbuffer latency=50 ! "
                                      "rtph264depay ! "
                                      "h264parse ! "
                                      "avdec_h264 ! "
                                      "videoconvert ! "
                                      "tee name=t "

                                      "t. ! queue ! "
                                      "glupload ! "
                                      "glcolorconvert ! "
                                      "qmlglsink name=video_sink "

                                      "t. ! queue name =recording_queue ! "
                                      "valve name =recording_valve  ! "
                                      "videoconvert ! "
                                      "video/x-raw,format=I420 ! "
                                      "x264enc tune=zerolatency ! "
                                      "mp4mux ! "
                                      "filesink name= file_sink location=/home/user/stream_record.mp4"
                                      ).arg(url);



    GError *error = nullptr;
    pipeline = gst_parse_launch(qPrintable(pipelineDescription), &error);
    if (!pipeline || error) {
        qCritical() << "Failed to create pipeline:" << (error ? error->message : "unknown error");
        if (error) g_error_free(error);
        return;
    }

    GstElement *videoSink = gst_bin_get_by_name(GST_BIN(pipeline), "video_sink");
    if (!videoSink) {
        qCritical() << "Failed to find qmlglsink in pipeline.";
        gst_object_unref(pipeline);
        pipeline = nullptr;
        return;
    }

    g_object_set(G_OBJECT(videoSink), "widget", videoItem, nullptr);
    gst_object_unref(videoSink);

    GstElement *recordingValve = gst_bin_get_by_name(GST_BIN(pipeline), "recording_valve");
    if (recordingValve) {
        g_object_set(G_OBJECT(recordingValve), "drop", TRUE, nullptr);  
        gst_object_unref(recordingValve);
    } else {
        qCritical() << "Failed to find recording valve in pipeline.";
    }

    GstBus *bus = gst_element_get_bus(pipeline);
    gst_bus_add_watch(bus, (GstBusFunc)GStreamerQmlSink::busCall, this);
    gst_object_unref(bus);

    GstStateChangeReturn ret = gst_element_set_state(pipeline, GST_STATE_PLAYING);
    if (ret == GST_STATE_CHANGE_FAILURE) {
        qCritical() << "Failed to set pipeline to PLAYING.";
        gst_object_unref(pipeline);
        pipeline = nullptr;
        return;
    }


    qInfo() << "Pipeline started successfully.";
}
void GStreamerQmlSink::startRecording()
{
    if (!pipeline) {
        qWarning() << "No active pipeline.";
        return;
    }

    GstElement *recordingValve = gst_bin_get_by_name(GST_BIN(pipeline), "recording_valve");
    if (!recordingValve) {
        qWarning() << "No active recording valve found.";
        return;
    }

    qInfo() << "Starting recording...";

    
    g_object_set(G_OBJECT(recordingValve), "drop", FALSE, nullptr);

    gst_object_unref(recordingValve);

    qInfo() << "Recording started successfully.";
}
void GStreamerQmlSink::stopRecording()
{
    if (!pipeline) {
        qWarning() << "No active pipeline.";
        return;
    }

    GstElement *recordingQueue = gst_bin_get_by_name(GST_BIN(pipeline), "recording_queue");
    if (!recordingQueue) {
        qWarning() << "No active recording queue found.";
        return;
    }

    qInfo() << "Stopping recording...";

    // Sadece kayıt kuyruğuna EOS sinyali gönderiyoruz
    GstEvent *eos_event = gst_event_new_eos();
    gst_element_send_event(recordingQueue, eos_event);

    gst_object_unref(recordingQueue);

    qInfo() << "Recording stopped successfully. MP4 file should be finalized.";
}

Thanks in advance @Joe .

4

Add this sentence to deepseek to learn more about valve
how to add valve to recording pipeline in gstreamer