Hello everyone,
I’m randomly experiencing untriggered pad-added with livekitwebrtcsrc (GStreamer/Node.js).
For example: when two participants with camera and microphone join the LiveKit room, the “pad-added” should trigger four times (once per audio/video stream per participant), but it randomly misses some streams.
No obvious errors are logged, and credentials/room configuration is valid.
Min code snippet:
import * as gi from 'node-gtk';
(async () => {
const roomName = 'room-name';
const livekitUrl = 'livekit-url';
const livekitApiKey = 'livekit-api-key';
const livekitApiSecret = 'livekit-api-secret';
const Gst = gi.require('Gst', '1.0');
const GObject = gi.require('GObject', '2.0');
gi.startLoop();
Gst.init(null);
const gString = (value) => {
const gValue = new GObject.Value();
gValue.init(GObject.TYPE_STRING);
gValue.setString(value);
return gValue;
};
const gBoolean = (value) => {
const gValue = new GObject.Value();
gValue.init(GObject.TYPE_BOOLEAN);
gValue.setBoolean(value);
return gValue;
};
const pipeline = Gst.Pipeline.new(`PI_${roomName}`);
const webrtcSrc = Gst.ElementFactory.make('livekitwebrtcsrc');
webrtcSrc.setProperty('signaller::ws-url', gString(livekitUrl));
webrtcSrc.setProperty('signaller::api-key', gString(livekitApiKey));
webrtcSrc.setProperty('signaller::secret-key', gString(livekitApiSecret));
webrtcSrc.setProperty('signaller::room-name', gString(roomName));
webrtcSrc.setProperty('signaller::identity', gString(`GS_${roomName}`));
pipeline.add(webrtcSrc);
/** @see {@link https://gstreamer.freedesktop.org/documentation/rswebrtc/livekitwebrtcsrc.html#pad-templates} */
webrtcSrc.connect('pad-added', (pad) => {
console.log('🎤📷 New pad added:', pad.getName());
if (pad.getName().startsWith('video_')) {
console.log('🔗 Linking video pad');
const videoQueue = Gst.ElementFactory.make('queue');
const videoConvert = Gst.ElementFactory.make('videoconvert');
const videoSink = Gst.ElementFactory.make('fakevideosink');
pipeline.add(videoQueue);
pipeline.add(videoConvert);
pipeline.add(videoSink);
videoQueue.link(videoConvert);
videoConvert.link(videoSink);
pad.link(videoQueue.getStaticPad('sink'));
} else if (pad.getName().startsWith('audio_')) {
console.log('🔗 Linking audio pad');
const audioQueue = Gst.ElementFactory.make('queue');
const audioConvert = Gst.ElementFactory.make('audioconvert');
const audioSink = Gst.ElementFactory.make('fakeaudiosink');
audioSink.setProperty('async', gBoolean(false));
pipeline.add(audioQueue);
pipeline.add(audioConvert);
pipeline.add(audioSink);
audioQueue.link(audioConvert);
audioConvert.link(audioSink);
pad.link(audioQueue.getStaticPad('sink'));
}
});
console.log('🚀 Setting pipeline state to PLAYING');
pipeline.setState(Gst.State.PLAYING);
await new Promise((resolve) => setTimeout(resolve, 20000));
console.log('🛑 Setting pipeline state to NULL');
pipeline.setState(Gst.State.NULL);
})();
2 participant meeting, the log is missing audio_unique_0
🚀 Setting pipeline state to PLAYING
0:00:00.590252091 116480 0x721bcc000b70 FIXME default gstutils.c:4088:gst_element_decorate_stream_id_internal:<nicesrc0> Creating random stream-id, consider implementing a deterministic way of creating a stream-id
0:00:00.590285866 116480 0x721bcc000b70 WARN GST_PADS gstpad.c:4392:gst_pad_peer_query:<nicesrc0:src> could not send sticky events
0:00:00.590664184 116480 0x420612e0 ERROR webrtcbin gstwebrtcbin.c:7145:gst_webrtc_bin_get_transceiver:<webrtcbin0> No transceiver for idx 0
0:00:00.590677260 116480 0x420612e0 WARN webrtcsrc net/webrtc/src/webrtcsrc/imp.rs:854:gstrswebrtc::webrtcsrc::imp::Session::remote_description_set::{{closure}}: Transceiver for idx 0 does not exist, GStreamer <= 1.24, adding it ourself
0:00:00.591017270 116480 0x420612e0 ERROR webrtcbin gstwebrtcbin.c:7145:gst_webrtc_bin_get_transceiver:<webrtcbin0> No transceiver for idx 1
0:00:00.591024959 116480 0x420612e0 WARN webrtcsrc net/webrtc/src/webrtcsrc/imp.rs:854:gstrswebrtc::webrtcsrc::imp::Session::remote_description_set::{{closure}}: Transceiver for idx 1 does not exist, GStreamer <= 1.24, adding it ourself
0:00:00.591089334 116480 0x420612e0 ERROR webrtcbin gstwebrtcbin.c:7145:gst_webrtc_bin_get_transceiver:<webrtcbin0> No transceiver for idx 2
0:00:00.591095358 116480 0x420612e0 WARN webrtcsrc net/webrtc/src/webrtcsrc/imp.rs:854:gstrswebrtc::webrtcsrc::imp::Session::remote_description_set::{{closure}}: Transceiver for idx 2 does not exist, GStreamer <= 1.24, adding it ourself
0:00:00.591355090 116480 0x420612e0 ERROR webrtcbin gstwebrtcbin.c:7145:gst_webrtc_bin_get_transceiver:<webrtcbin0> No transceiver for idx 3
0:00:00.591362273 116480 0x420612e0 WARN webrtcsrc net/webrtc/src/webrtcsrc/imp.rs:854:gstrswebrtc::webrtcsrc::imp::Session::remote_description_set::{{closure}}: Transceiver for idx 3 does not exist, GStreamer <= 1.24, adding it ourself
0:00:00.802931353 116480 0x721bcc001470 FIXME default gstutils.c:4088:gst_element_decorate_stream_id_internal:<dtlsenc0> Creating random stream-id, consider implementing a deterministic way of creating a stream-id
0:00:01.054735544 116480 0x721bcc001b30 FIXME default gstutils.c:4088:gst_element_decorate_stream_id_internal:<appsrc0> Creating random stream-id, consider implementing a deterministic way of creating a stream-id
0:00:01.055531250 116480 0x721bcc001d70 FIXME basesink gstbasesink.c:3399:gst_base_sink_default_event:<appsink0> stream-start event without group-id. Consider implementing group-id handling in the upstream elements
0:00:01.056292386 116480 0x721bcc001fb0 FIXME default gstutils.c:4088:gst_element_decorate_stream_id_internal:<appsrc1> Creating random stream-id, consider implementing a deterministic way of creating a stream-id
0:00:01.056829293 116480 0x721bcc0021f0 FIXME basesink gstbasesink.c:3399:gst_base_sink_default_event:<appsink1> stream-start event without group-id. Consider implementing group-id handling in the upstream elements
0:00:01.166966280 116480 0x721bcc0018f0 WARN webrtcbin gstwebrtcbin.c:5096:try_match_transceiver_with_fec_decoder:<webrtctransceiver1> failed to match fec decoder with transceiver
0:00:01.167012581 116480 0x721bcc0018f0 WARN webrtcbin gstwebrtcbin.c:5096:try_match_transceiver_with_fec_decoder:<webrtctransceiver3> failed to match fec decoder with transceiver
🎤📷 New pad added: audio_unique_1
🔗 Linking audio pad
0:00:01.176902155 116480 0x721bcc0018f0 FIXME decodebin3 gstdecodebin3.c:1690:update_requested_selection:<decodebin3-0> Implement EXPOSE_ALL_MODE
0:00:01.176933838 116480 0x721bcc0018f0 FIXME decodebin3 gstdecodebin3-parse.c:454:unblock_pending_input:<decodebin3-0> Re-use existing input streams if/when possible
0:00:01.177194303 116480 0x721bcc002670 FIXME decodebin3 gstdecodebin3.c:2273:get_output_for_slot:<decodebin3-0> emit autoplug-continue
0:00:01.177203374 116480 0x721bcc002670 FIXME decodebin3 gstdecodebin3.c:2276:get_output_for_slot:<decodebin3-0> Handle EXPOSE_ALL_MODE
0:00:01.178989720 116480 0x721bcc002670 WARN GST_PADS gstpad.c:4392:gst_pad_peer_query:<livekitwebrtcsrc0:audio_unique_1> could not send sticky events
0:00:01.208328151 116480 0x721bcc002430 WARN webrtcbin gstwebrtcbin.c:5096:try_match_transceiver_with_fec_decoder:<webrtctransceiver0> failed to match fec decoder with transceiver
0:00:01.208350637 116480 0x721bcc002430 FIXME webrtcbin gstwebrtcbin.c:5086:try_match_transceiver_with_fec_decoder:<webrtctransceiver0> cannot
0:00:01.208359956 116480 0x721bcc002430 WARN webrtcbin gstwebrtcbin.c:5096:try_match_transceiver_with_fec_decoder:<webrtctransceiver1> failed to match fec decoder with transceiver
0:00:01.208366964 116480 0x721bcc002430 WARN webrtcbin gstwebrtcbin.c:5096:try_match_transceiver_with_fec_decoder:<webrtctransceiver2> failed to match fec decoder with transceiver
0:00:01.208372742 116480 0x721bcc002430 FIXME webrtcbin gstwebrtcbin.c:5086:try_match_transceiver_with_fec_decoder:<webrtctransceiver2> cannot
0:00:01.208379634 116480 0x721bcc002430 WARN webrtcbin gstwebrtcbin.c:5096:try_match_transceiver_with_fec_decoder:<webrtctransceiver3> failed to match fec decoder with transceiver
🎤📷 New pad added: video_unique_0
🔗 Linking video pad
0:00:01.221207484 116480 0x721bcc002430 FIXME decodebin3 gstdecodebin3.c:1690:update_requested_selection:<decodebin3-1> Implement EXPOSE_ALL_MODE
0:00:01.221247348 116480 0x721bcc002430 FIXME decodebin3 gstdecodebin3-parse.c:454:unblock_pending_input:<decodebin3-1> Re-use existing input streams if/when possible
0:00:01.221563949 116480 0x721bcc0028b0 FIXME decodebin3 gstdecodebin3.c:2273:get_output_for_slot:<decodebin3-1> emit autoplug-continue
0:00:01.221576491 116480 0x721bcc0028b0 FIXME decodebin3 gstdecodebin3.c:2276:get_output_for_slot:<decodebin3-1> Handle EXPOSE_ALL_MODE
0:00:01.230326108 116480 0x721bcc0028b0 WARN vadisplay gstvadisplay.c:401:gst_va_display_initialize:<vadisplaydrm1> vaInitialize: unknown libva error
0:00:01.292402194 116480 0x721bcc0028b0 WARN GST_PADS gstpad.c:4392:gst_pad_peer_query:<livekitwebrtcsrc0:video_unique_0> could not send sticky events
0:00:01.328293490 116480 0x721bcc001230 WARN webrtcbin gstwebrtcbin.c:5096:try_match_transceiver_with_fec_decoder:<webrtctransceiver0> failed to match fec decoder with transceiver
0:00:01.328310436 116480 0x721bcc001230 WARN webrtcbin gstwebrtcbin.c:5096:try_match_transceiver_with_fec_decoder:<webrtctransceiver0> failed to match fec decoder with transceiver
0:00:01.328315711 116480 0x721bcc001230 FIXME webrtcbin gstwebrtcbin.c:5086:try_match_transceiver_with_fec_decoder:<webrtctransceiver0> cannot
0:00:01.328324388 116480 0x721bcc001230 FIXME webrtcbin gstwebrtcbin.c:5086:try_match_transceiver_with_fec_decoder:<webrtctransceiver1> cannot
0:00:01.328328871 116480 0x721bcc001230 FIXME webrtcbin gstwebrtcbin.c:5086:try_match_transceiver_with_fec_decoder:<webrtctransceiver1> cannot
0:00:01.328332824 116480 0x721bcc001230 WARN webrtcbin gstwebrtcbin.c:5096:try_match_transceiver_with_fec_decoder:<webrtctransceiver1> failed to match fec decoder with transceiver
0:00:01.328342928 116480 0x721bcc001230 WARN webrtcbin gstwebrtcbin.c:5096:try_match_transceiver_with_fec_decoder:<webrtctransceiver2> failed to match fec decoder with transceiver
0:00:01.328347595 116480 0x721bcc001230 WARN webrtcbin gstwebrtcbin.c:5096:try_match_transceiver_with_fec_decoder:<webrtctransceiver2> failed to match fec decoder with transceiver
0:00:01.328351478 116480 0x721bcc001230 FIXME webrtcbin gstwebrtcbin.c:5086:try_match_transceiver_with_fec_decoder:<webrtctransceiver2> cannot
0:00:01.328358108 116480 0x721bcc001230 FIXME webrtcbin gstwebrtcbin.c:5086:try_match_transceiver_with_fec_decoder:<webrtctransceiver3> cannot
0:00:01.328362428 116480 0x721bcc001230 FIXME webrtcbin gstwebrtcbin.c:5086:try_match_transceiver_with_fec_decoder:<webrtctransceiver3> cannot
0:00:01.328366202 116480 0x721bcc001230 WARN webrtcbin gstwebrtcbin.c:5096:try_match_transceiver_with_fec_decoder:<webrtctransceiver3> failed to match fec decoder with transceiver
🎤📷 New pad added: video_unique_1
🔗 Linking video pad
0:00:01.336580905 116480 0x721bcc001230 FIXME decodebin3 gstdecodebin3.c:1690:update_requested_selection:<decodebin3-2> Implement EXPOSE_ALL_MODE
0:00:01.336608871 116480 0x721bcc001230 FIXME decodebin3 gstdecodebin3-parse.c:454:unblock_pending_input:<decodebin3-2> Re-use existing input streams if/when possible
0:00:01.336898114 116480 0x721bcc002af0 FIXME decodebin3 gstdecodebin3.c:2273:get_output_for_slot:<decodebin3-2> emit autoplug-continue
0:00:01.336911329 116480 0x721bcc002af0 FIXME decodebin3 gstdecodebin3.c:2276:get_output_for_slot:<decodebin3-2> Handle EXPOSE_ALL_MODE
0:00:01.340658929 116480 0x721bcc002af0 WARN GST_PADS gstpad.c:4392:gst_pad_peer_query:<livekitwebrtcsrc0:video_unique_1> could not send sticky events
0:00:06.242689174 116480 0x721bd00629d0 WARN rtpsession rtpsession.c:4067:session_nack: Removing 1 expired NACKS
0:00:06.242784468 116480 0x721bd00629d0 WARN rtpsession rtpsession.c:4067:session_nack: Removing 1 expired NACKS
0:00:06.242810337 116480 0x721bd00629d0 WARN rtpsession rtpsession.c:4067:session_nack: Removing 1 expired NACKS
🛑 Setting pipeline state to NULL
0:00:20.047714793 116480 0x721b4810a230 WARN webrtcsrc net/webrtc/src/webrtcsrc/imp.rs:1483:gstrswebrtc::webrtcsrc::imp::BaseWebRTCSrc::end_session:<livekitwebrtcsrc0> failed to send EOS on audio_unique_1
0:00:20.047770249 116480 0x721b4810a230 WARN webrtcsrc net/webrtc/src/webrtcsrc/imp.rs:1483:gstrswebrtc::webrtcsrc::imp::BaseWebRTCSrc::end_session:<livekitwebrtcsrc0> failed to send EOS on video_unique_0
0:00:20.047797181 116480 0x721b4810a230 WARN webrtcsrc net/webrtc/src/webrtcsrc/imp.rs:1483:gstrswebrtc::webrtcsrc::imp::BaseWebRTCSrc::end_session:<livekitwebrtcsrc0> failed to send EOS on video_unique_1
0:00:20.100268727 116480 0x721b4810a230 WARN webrtcsrc net/webrtc/src/webrtcsrc/imp.rs:1362:gstrswebrtc::webrtcsrc::imp::BaseWebRTCSrc::start_session::{{closure}}:<livekitwebrtcsrc0> session "unique" not found
0:00:20.100291422 116480 0x721b4810a230 WARN webrtcsrc net/webrtc/src/webrtcsrc/imp.rs:1362:gstrswebrtc::webrtcsrc::imp::BaseWebRTCSrc::start_session::{{closure}}:<livekitwebrtcsrc0> session "unique" not found
0:00:20.100300224 116480 0x721b4810a230 WARN webrtcsrc net/webrtc/src/webrtcsrc/imp.rs:1362:gstrswebrtc::webrtcsrc::imp::BaseWebRTCSrc::start_session::{{closure}}:<livekitwebrtcsrc0> session "unique" not found
0:00:20.100678706 116480 0x721b4810a230 ERROR webrtcsrc net/webrtc/src/webrtcsrc/imp.rs:1414:gstrswebrtc::webrtcsrc::imp::BaseWebRTCSrc::start_session::{{closure}}:<livekitwebrtcsrc0> session "unique" not found
0:00:20.100696197 116480 0x721b4810a230 ERROR webrtcsrc net/webrtc/src/webrtcsrc/imp.rs:1414:gstrswebrtc::webrtcsrc::imp::BaseWebRTCSrc::start_session::{{closure}}:<livekitwebrtcsrc0> session "unique" not found
0:00:20.100705429 116480 0x721b4810a230 ERROR webrtcsrc net/webrtc/src/webrtcsrc/imp.rs:1414:gstrswebrtc::webrtcsrc::imp::BaseWebRTCSrc::start_session::{{closure}}:<livekitwebrtcsrc0> session "unique" not found
What are causes for random pad-added not being triggered?
Any insights or suggestions would be greatly appreciated! Thank you in advance. 