How to add and compiler gstreamer element?

[tranhien1612]

Your Question

Hi, i want to add gstreamer element more. I use flv and rtmpsink element.

At first when I called the gst_element_factory_make("flvmux", nullptr)) and gst_element_factory_make("rtmpsink", nullptr)) function I got the following error message:

  start gst_element_factory_make('flvmux') failed
  start gst_element_factory_make('rtmpsink') failed

After, I added some code in file GStreamer.cc:

#if defined(__android__) || defined(__ios__)
    GST_PLUGIN_STATIC_DECLARE(coreelements);
    GST_PLUGIN_STATIC_DECLARE(playback);
    GST_PLUGIN_STATIC_DECLARE(libav);
    GST_PLUGIN_STATIC_DECLARE(rtp);
    GST_PLUGIN_STATIC_DECLARE(flv); 
    GST_PLUGIN_STATIC_DECLARE(rtmp); 
    GST_PLUGIN_STATIC_DECLARE(rtsp);
    GST_PLUGIN_STATIC_DECLARE(udp);
    GST_PLUGIN_STATIC_DECLARE(videoparsersbad);
    GST_PLUGIN_STATIC_DECLARE(x264);
    GST_PLUGIN_STATIC_DECLARE(rtpmanager);
    GST_PLUGIN_STATIC_DECLARE(isomp4);
    GST_PLUGIN_STATIC_DECLARE(matroska);
    GST_PLUGIN_STATIC_DECLARE(mpegtsdemux);
    GST_PLUGIN_STATIC_DECLARE(opengl);
    GST_PLUGIN_STATIC_DECLARE(tcp);
#if defined(__android__)
    GST_PLUGIN_STATIC_DECLARE(androidmedia);
#elif defined(__ios__)
    GST_PLUGIN_STATIC_DECLARE(applemedia);
#endif
....

#if defined(__android__) || defined(__ios__)
    GST_PLUGIN_STATIC_REGISTER(coreelements);
    GST_PLUGIN_STATIC_REGISTER(playback);
    GST_PLUGIN_STATIC_REGISTER(libav);
    GST_PLUGIN_STATIC_REGISTER(rtp);
    GST_PLUGIN_STATIC_REGISTER(flv);
    GST_PLUGIN_STATIC_REGISTER(rtmp); 
    GST_PLUGIN_STATIC_REGISTER(rtsp);
    GST_PLUGIN_STATIC_REGISTER(udp);
    GST_PLUGIN_STATIC_REGISTER(videoparsersbad);
    GST_PLUGIN_STATIC_REGISTER(x264);
    GST_PLUGIN_STATIC_REGISTER(rtpmanager);
    GST_PLUGIN_STATIC_REGISTER(isomp4);
    GST_PLUGIN_STATIC_REGISTER(matroska);
    GST_PLUGIN_STATIC_REGISTER(mpegtsdemux);
    GST_PLUGIN_STATIC_REGISTER(opengl);
    GST_PLUGIN_STATIC_REGISTER(tcp);

#if defined(__android__)
    GST_PLUGIN_STATIC_REGISTER(androidmedia);
#elif defined(__ios__)
    GST_PLUGIN_STATIC_REGISTER(applemedia);
#endif
#endif

it seems like the flv element was added successfully (because i didn't error start gst_element_factory_make('flvmux') failed ) . But I get an error with the "rtmpsink" element:

I don't have much knowledge about this problem, please help me deal with it.

[HTRamsey]

https://github.com/mavlink/qgroundcontrol/blob/4d832cc3a6378f284c63d1e4a41a2634d382eedd/src/VideoReceiver/VideoReceiver.pri#L87

[tranhien1612]

qgroundcontrol/src/VideoReceiver/VideoReceiver.pri

Line 87 in 4d832cc

LIBS += -L$$GST_ROOT/lib/gstreamer-1.0 \

i checked and it has that command line. because i want to add elements for rtmp so i used gstreamer version 1.20.7, because i tried with gstreamer version 1.18.6 but got error when adding those 2 elements

[HTRamsey]

you added your plugins to that VideoReceiver.pri file?

[tranhien1612]

@HTRamsey I have added some plugins, but I don't know if there are any missing plugins.

[HTRamsey]

I looked at gstrtmp.pc and you need to link to librtmp as well

[HTRamsey]

so you would add -lrtmp in this section https://github.com/mavlink/qgroundcontrol/blob/4d832cc3a6378f284c63d1e4a41a2634d382eedd/src/VideoReceiver/VideoReceiver.pri#L107

[tranhien1612]

Thanks for your help. I will try it tomorrow since it is dark now. By the way, I want to ask the following question: I want to create a gstreamer pipe for rtmp as follows, I tested it using command line. I am trying to add it to qgrouncontrol following the structure you are doing. Will this affect the system?

//              +-->queue-->_decoderValve[-->_decoder-->_videoSink]
//              |
// _source-->_tee
//              |
//              +-->queue-->_recorderValve[-->_fileSink]
//              |
//              |
//              +-->queue-->rtph264depay-->h264parse-->flvmux-->rtmpsink

[tranhien1612]

so you would add -lrtmp in this section

qgroundcontrol/src/VideoReceiver/VideoReceiver.pri

Line 107 in 4d832cc

LIBS += -L$$GST_ROOT/lib \

i tried add -lrtmp in this section, but it still has the same error. I don't know what the reason is, I'm currently using rtmp2sink and I don't see any errors when compiling.