Method AddSubscriber

pkg/rtc/mediatrackreceiver.go:530–606

AddSubscriber subscribes sub to current mediaTrack

(sub types.LocalParticipant)

// AddSubscriber subscribes sub to current mediaTrack
func (t *MediaTrackReceiver) AddSubscriber(sub types.LocalParticipant) (types.SubscribedTrack, error) {
	t.lock.RLock()
	if t.state != mediaTrackReceiverStateOpen {
		t.lock.RUnlock()
		return nil, ErrNotOpen
	}

	receivers := t.receivers
	potentialCodecs := make([]webrtc.RTPCodecParameters, len(t.potentialCodecs))
	copy(potentialCodecs, t.potentialCodecs)
	t.lock.RUnlock()

	if len(receivers) == 0 {
		// cannot add, no receiver
		return nil, ErrNoReceiver
	}

	for _, receiver := range receivers {
		if receiver.IsRegressed() {
			continue
		}

		codec := receiver.Codec()
		var found bool
		for _, pc := range potentialCodecs {
			if mime.IsMimeTypeStringEqual(codec.MimeType, pc.MimeType) {
				found = true
				break
			}
		}
		if !found {
			potentialCodecs = append(potentialCodecs, codec)
		}
	}

	streamId := string(t.PublisherID())
	if sub.ProtocolVersion().SupportsPackedStreamId() {
		// when possible, pack both IDs in streamID to allow new streams to be generated
		// react-native-webrtc still uses stream based APIs and require this
		streamId = PackStreamID(t.PublisherID(), t.ID())
	}

	tLogger := LoggerWithTrack(sub.GetLogger(), t.ID(), t.params.IsRelayed)
	wr := NewWrappedReceiver(WrappedReceiverParams{
		Receivers:      receivers,
		TrackID:        t.ID(),
		StreamId:       streamId,
		UpstreamCodecs: potentialCodecs,
		Logger:         tLogger,
		DisableRed:     !IsRedEnabled(t.TrackInfo()) || !t.params.AudioConfig.ActiveREDEncoding,
		IsEncrypted:    t.IsEncrypted(),
	})
	subID := sub.ID()
	subTrack, err := t.MediaTrackSubscriptions.AddSubscriber(sub, wr)

	// media track could have been closed while adding subscription
	remove := false
	isExpectedToResume := false