Method AddTrack

pkg/rtc/transport.go:1057–1112

(
	trackLocal webrtc.TrackLocal,
	params types.AddTrackParams,
	enabledCodecs []*livekit.Codec,
	rtcpFeedbackConfig RTCPFeedbackConfig,
)

}

func (t *PCTransport) AddTrack(
	trackLocal webrtc.TrackLocal,
	params types.AddTrackParams,
	enabledCodecs []*livekit.Codec,
	rtcpFeedbackConfig RTCPFeedbackConfig,
) (sender *webrtc.RTPSender, transceiver *webrtc.RTPTransceiver, err error) {
	t.lock.Lock()
	canReuse := t.canReuseTransceiver
	td, ok := t.previousTrackDescription[trackLocal.ID()]
	if ok {
		delete(t.previousTrackDescription, trackLocal.ID())
	}
	t.lock.Unlock()

	// keep track use same mid after migration if possible
	if td != nil && td.sender != nil {
		for _, tr := range t.pc.GetTransceivers() {
			if tr.Mid() == td.mid {
				return td.sender, tr, tr.SetSender(td.sender, trackLocal)
			}
		}
	}

	// if never negotiated with client, can't reuse transceiver for track not subscribed before migration
	if !canReuse {
		return t.AddTransceiverFromTrack(trackLocal, params, enabledCodecs, rtcpFeedbackConfig)
	}

	sender, err = t.pc.AddTrack(trackLocal)
	if err != nil {
		return
	}

	for _, tr := range t.pc.GetTransceivers() {
		if tr.Sender() == sender {
			transceiver = tr
			break
		}
	}

	if transceiver == nil {
		err = ErrNoTransceiver
		return
	}

	t.queueOrConfigureSender(
		transceiver,
		enabledCodecs,
		rtcpFeedbackConfig,
		params.Stereo,
		!params.Red || !t.params.ClientInfo.SupportsAudioRED(),
	)

	t.adjustNumOutstandingMedia(transceiver)
	return
}

func (t *PCTransport) AddTransceiverFromTrack(