server back to working, tho only works when client joins first

go.mod

@@ -3,7 +3,6 @@ module github.com/livekit/livekit-server
 go 1.15
 
 require (
-	github.com/gammazero/deque v0.0.0-20201010052221-3932da5530cc
 	github.com/golang/protobuf v1.4.3
 	github.com/google/uuid v1.1.2
 	github.com/google/wire v0.4.0
@@ -14,21 +13,16 @@ require (
 	github.com/pion/interceptor v0.0.5
 	github.com/pion/ion-log v1.0.0
 	github.com/pion/ion-sfu v1.6.3
-	github.com/pion/randutil v0.1.0
 	github.com/pion/rtcp v1.2.6
 	github.com/pion/rtp v1.6.1
 	github.com/pion/sdp/v3 v3.0.3
 	github.com/pion/stun v0.3.5
 	github.com/pion/webrtc/v3 v3.0.0-beta.15.0.20201209023348-63401a8837fb
 	github.com/pkg/errors v0.9.1
-	github.com/stretchr/testify v1.6.1
 	github.com/twitchtv/twirp v7.1.0+incompatible
 	github.com/urfave/cli/v2 v2.2.0
 	github.com/urfave/negroni v1.0.0
 	go.uber.org/zap v1.16.0
-	golang.org/x/crypto v0.0.0-20201208171446-5f87f3452ae9 // indirect
-	golang.org/x/net v0.0.0-20201207224615-747e23833adb // indirect
-	golang.org/x/sys v0.0.0-20201207223542-d4d67f95c62d // indirect
 	golang.org/x/tools v0.0.0-20200815165600-90abf76919f3 // indirect
 	google.golang.org/protobuf v1.25.0
 	gopkg.in/yaml.v2 v2.3.0

pkg/rtc/errors.go

@@ -3,8 +3,5 @@ package rtc
 import "errors"
 
 var (
-	ErrRoomIdMissing          = errors.New("roomId is not set")
-	ErrPeerExists             = errors.New("peer already exists")
-	ErrPeerNotConnected       = errors.New("peer has not been connected")
-	ErrUnsupportedPayloadType = errors.New("peer does not support payload type")
+	ErrRoomIdMissing = errors.New("roomId is not set")
 )

pkg/rtc/forwarder.go

@@ -26,6 +26,7 @@ type Forwarder interface {
 	Start()
 	Close()
 	CreatedAt() time.Time
+	Track() *sfu.DownTrack
 
 	OnClose(func(Forwarder))
 }
@@ -129,6 +130,10 @@ func (f *SimpleForwarder) CreatedAt() time.Time {
 	return f.createdAt
 }
 
+func (f *SimpleForwarder) Track() *sfu.DownTrack {
+	return f.track
+}
+
 // rtcpWorker receives RTCP packets from the destination peer
 // this include packet loss packets
 func (f *SimpleForwarder) rtcpWorker() {

pkg/rtc/participant.go

@@ -73,6 +73,7 @@ func NewParticipant(conf *WebRTCConfig, sc SignalConnection, name string) (*Part
 		ctx:            ctx,
 		cancel:         cancel,
 		bi:             bi,
+		rtcpCh:         make(chan []rtcp.Packet, 10),
 		downTracks:     make(map[string][]*sfu.DownTrack),
 		state:          livekit.ParticipantInfo_JOINING,
 		lock:           sync.RWMutex{},
@@ -190,8 +191,6 @@ func (p *Participant) Answer(sdp webrtc.SessionDescription) (answer webrtc.Sessi
 			return
 		}
 
-		logger.GetLogger().Debugw("created new offer", "offer", offer, "onOffer", p.OnOffer)
-
 		logger.GetLogger().Debugw("sending available offer to participant")
 		err = p.sigConn.WriteResponse(&livekit.SignalResponse{
 			Message: &livekit.SignalResponse_Negotiate{
@@ -230,7 +229,9 @@ func (p *Participant) addDownTrack(streamId string, dt *sfu.DownTrack) {
 	p.lock.Lock()
 	p.downTracks[streamId] = append(p.downTracks[streamId], dt)
 	p.lock.Unlock()
-	p.scheduleDownTrackBindingReports(streamId)
+	dt.OnBind(func() {
+		go p.scheduleDownTrackBindingReports(streamId)
+	})
 }
 
 func (p *Participant) removeDownTrack(streamId string, dt *sfu.DownTrack) {
@@ -371,10 +372,10 @@ func (p *Participant) scheduleDownTrackBindingReports(streamId string) {
 	}
 
 	go func() {
-		pkts := pkts
+		batch := pkts
 		i := 0
 		for {
-			if err := p.peerConn.WriteRTCP(pkts); err != nil {
+			if err := p.peerConn.WriteRTCP(batch); err != nil {
 				logger.GetLogger().Debugw("Sending track binding reports",
 					"participant", p.id,
 					"err", err)

pkg/rtc/track.go

@@ -105,11 +105,14 @@ func (t *Track) AddSubscriber(participant *Participant) error {
 		if participant.peerConn.ConnectionState() == webrtc.PeerConnectionStateClosed {
 			return
 		}
-		if err := participant.peerConn.RemoveTrack(transceiver.Sender()); err != nil {
-			if _, ok := err.(*rtcerr.InvalidStateError); !ok {
-				logger.GetLogger().Warnw("could not remove remoteTrack from forwarder",
-					"participant", participant.ID(),
-					"err", err)
+		sender := transceiver.Sender()
+		if sender != nil {
+			if err := participant.peerConn.RemoveTrack(sender); err != nil {
+				if _, ok := err.(*rtcerr.InvalidStateError); !ok {
+					logger.GetLogger().Warnw("could not remove remoteTrack from forwarder",
+						"participant", participant.ID(),
+						"err", err)
+				}
 			}
 		}
 
@@ -195,7 +198,15 @@ func (t *Track) forwardRTPWorker() {
 				continue
 			}
 
-			if err != nil {
+			if err == sfu.ErrRequiresKeyFrame {
+				logger.GetLogger().Infow("keyframe required, sending PLI")
+				// queue up a PLI, but don't block channel
+				go func() {
+					t.rtcpCh <- []rtcp.Packet{
+						&rtcp.PictureLossIndication{SenderSSRC: forwarder.Track().SSRC(), MediaSSRC: pkt.SSRC},
+					}
+				}()
+			} else if err != nil {
 				logger.GetLogger().Warnw("could not forward packet to participant",
 					"src", t.participantId,
 					"dest", dstId,

pkg/sfu/downtrack.go

@@ -230,10 +230,7 @@ func (d *DownTrack) writeSimpleRTP(pkt rtp.Packet) error {
 			}
 			if !relay {
 				// TODO: how do we sent PLI to the source?
-				//d.receiver.SendRTCP([]rtcp.Packet{
-				//	&rtcp.PictureLossIndication{SenderSSRC: d.ssrc, MediaSSRC: pkt.SSRC},
-				//})
-				return ErrRequiresKeyFrame
+				//return ErrRequiresKeyFrame
 			}
 		}
 		d.snOffset = pkt.SequenceNumber - d.lastSN - 1