Playback recorded video from gstreamer does not start at 0s but between 5 and 10s

[Nicolas Dufresne]

Le jeudi 09 septembre 2021 à 15:53 +0200, Arnaud Tullio via gstreamer-devel a
écrit :
> I stream and record my video like in the code below. For information, when I
> start the process, I have to wait between 5 and 10 seconds before having the
> first frame to appears. The problem is that when I playback the video with VLC
> for example the video start a 5 or 10s it depends on the time I have waited
> before having the first frame. It is the same at the end of the video, the
> video continue during 5 and 10 seconds after the timebar on vlc have reached
> the end.
> Does someone have and idea ? How can I be sure that the video start and finish
> at the right time?
> void MainWindow::OnStop(wxCommandEvent&) is to Stop the record and void
> MainWindow::OnSave(wxCommandEvent&) is to start saving the stream
> void MainWindow::OnStop(wxCommandEvent&)
> 
>         gst_element_send_event((*ptrstats).pipeline, gst_event_new_eos());
>         gst_bus_timed_pop_filtered((*ptrstats).bus, GST_CLOCK_TIME_NONE,
> GST_MESSAGE_EOS);
>         GstStateChangeReturn ret = gst_element_set_state((*ptrstats).pipeline,
> GST_STATE_NULL);
> }
>     
> void MainWindow::OnSave(wxCommandEvent&)
>     {
>             std::string strPathVideo = m_VideoPath + CreateFileName("mkv");
>     
>             GError* error = NULL;
>             GstElement* source;
>             GstElement* filesink;
>             GstElement* matrox;
>             GstElement* clocktime;
>             GstElement* textoverlay;
>             GstCaps* caps = gst_caps_new_simple("application/x-rtp",
>                 "media", G_TYPE_STRING, "video",
>                 "payload", G_TYPE_INT, 96,
>                 "encoding-name", G_TYPE_STRING, "H264",
>                 NULL);
>     
> 
>             (*ptrstats).pipeline = gst_parse_launch("udpsrc name=source
> !rtph264depay !h264parse !avdec_h264 ! tee name = t !queue !videoconvert

You are missing few spaces here, and missing the rtpjitterbuffer element between
udpsrc and rtph264depay.

> !matroskamux name=matrox !filesink name=myFile t. ! queue ! videoconvert
> !d3dvideosink name=mysink sync=false", &error);
> 
>             if (!(*ptrstats).pipeline) {
>                  outfile << "Save : ", error->message ,"\n";
>                  exit(1);
>             }
>  
>             filesink = gst_bin_get_by_name(GST_BIN((*ptrstats).pipeline),
> "myFile");
>             g_object_set(filesink, "location", strPathVideo.c_str(), NULL);
>     
>             matrox = gst_bin_get_by_name(GST_BIN((*ptrstats).pipeline),
> "matrox");
>             g_object_set(G_OBJECT(matrox), "offset-to-zero", true, NULL);
>     
>             source = gst_bin_get_by_name(GST_BIN((*ptrstats).pipeline),
> "source");
>             g_object_set(G_OBJECT(source), "caps", caps, NULL);
>             g_object_set(G_OBJECT(source), "port", m_port, NULL);
> 
>     
>             (*ptrstats).bus =
> gst_element_get_bus(GST_ELEMENT((*ptrstats).pipeline));
>     
>             GstStateChangeReturn ret =
> gst_element_set_state((*ptrstats).pipeline, GST_STATE_PLAYING);
>         
>     }
> 
>