From 003fae81d7a01b7898f947dd8546f87b9ddb8f3c Mon Sep 17 00:00:00 2001
From: OrlandoCo <luisorlando.co@gmail.com>
Date: Sun, 14 Mar 2021 18:54:20 -0600
Subject: [PATCH] fix(sfu): will move layers as they arrive (#469)

---
 pkg/sfu/publisher.go |  2 +-
 pkg/sfu/receiver.go  | 55 +++++++++++++++++++++++++++++++++++++-------
 pkg/sfu/router.go    | 10 +-------
 3 files changed, 49 insertions(+), 18 deletions(-)

diff --git a/pkg/sfu/publisher.go b/pkg/sfu/publisher.go
index bcf6a246f..80b9c21b1 100644
--- a/pkg/sfu/publisher.go
+++ b/pkg/sfu/publisher.go
@@ -39,8 +39,8 @@ func NewPublisher(session *Session, id string, cfg WebRTCTransportConfig) (*Publ
 	p := &Publisher{
 		id:      id,
 		pc:      pc,
-		session: session,
 		router:  newRouter(id, pc, session, cfg.router),
+		session: session,
 	}
 
 	pc.OnTrack(func(track *webrtc.TrackRemote, receiver *webrtc.RTPReceiver) {
diff --git a/pkg/sfu/receiver.go b/pkg/sfu/receiver.go
index 0dd4ae367..293f86649 100644
--- a/pkg/sfu/receiver.go
+++ b/pkg/sfu/receiver.go
@@ -20,7 +20,7 @@ type Receiver interface {
 	Codec() webrtc.RTPCodecParameters
 	Kind() webrtc.RTPCodecType
 	SSRC(layer int) uint32
-	AddUpTrack(track *webrtc.TrackRemote, buffer *buffer.Buffer)
+	AddUpTrack(track *webrtc.TrackRemote, buffer *buffer.Buffer, bestQualityFirst bool)
 	AddDownTrack(track *DownTrack, bestQualityFirst bool)
 	SubDownTrack(track *DownTrack, layer int) error
 	GetBitrate() [3]uint64
@@ -94,7 +94,7 @@ func (w *WebRTCReceiver) Kind() webrtc.RTPCodecType {
 	return w.kind
 }
 
-func (w *WebRTCReceiver) AddUpTrack(track *webrtc.TrackRemote, buff *buffer.Buffer) {
+func (w *WebRTCReceiver) AddUpTrack(track *webrtc.TrackRemote, buff *buffer.Buffer, bestQualityFirst bool) {
 	var layer int
 
 	switch track.RID() {
@@ -106,9 +106,31 @@ func (w *WebRTCReceiver) AddUpTrack(track *webrtc.TrackRemote, buff *buffer.Buff
 		layer = 0
 	}
 
+	if w.isSimulcast {
+		if bestQualityFirst {
+			for l := 0; l < layer; l++ {
+				w.locks[l].Lock()
+				for _, dt := range w.downTracks[l] {
+					dt.SwitchSpatialLayer(int64(layer), false)
+				}
+				w.locks[l].Unlock()
+			}
+		} else {
+			for l := 2; l != layer; l-- {
+				w.locks[l].Lock()
+				for _, dt := range w.downTracks[l] {
+					dt.SwitchSpatialLayer(int64(layer), false)
+				}
+				w.locks[l].Unlock()
+			}
+		}
+	}
+
+	w.locks[layer].Lock()
 	w.upTracks[layer] = track
 	w.buffers[layer] = buff
 	w.downTracks[layer] = make([]*DownTrack, 0, 10)
+	w.locks[layer].Unlock()
 	go w.writeRTP(layer)
 }
 
@@ -123,31 +145,39 @@ func (w *WebRTCReceiver) AddDownTrack(track *DownTrack, bestQualityFirst bool) {
 				}
 			}
 		}
+		w.locks[layer].Lock()
+		if downTrackSubscribed(w.downTracks[layer], track) {
+			w.locks[layer].Unlock()
+			return
+		}
 		track.SetInitialLayers(int64(layer), 2)
 		track.maxSpatialLayer = 2
 		track.maxTemporalLayer = 2
 		track.trackType = SimulcastDownTrack
 		track.payload = packetFactory.Get().([]byte)
 	} else {
+		w.locks[layer].Lock()
+		if downTrackSubscribed(w.downTracks[layer], track) {
+			w.locks[layer].Unlock()
+			return
+		}
 		track.SetInitialLayers(0, 0)
 		track.trackType = SimpleDownTrack
 	}
 
-	w.locks[layer].Lock()
 	w.downTracks[layer] = append(w.downTracks[layer], track)
 	w.locks[layer].Unlock()
 }
 
 func (w *WebRTCReceiver) SubDownTrack(track *DownTrack, layer int) error {
 	w.locks[layer].Lock()
-	if dts := w.downTracks[layer]; dts != nil {
-		w.downTracks[layer] = append(dts, track)
-	} else {
+	if buf := w.buffers[layer]; buf != nil {
+		w.downTracks[layer] = append(w.downTracks[layer], track)
 		w.locks[layer].Unlock()
-		return errNoReceiverFound
+		return nil
 	}
 	w.locks[layer].Unlock()
-	return nil
+	return errNoReceiverFound
 }
 
 func (w *WebRTCReceiver) GetBitrate() [3]uint64 {
@@ -310,3 +340,12 @@ func (w *WebRTCReceiver) closeTracks() {
 		w.onCloseHandler()
 	}
 }
+
+func downTrackSubscribed(dts []*DownTrack, dt *DownTrack) bool {
+	for _, cdt := range dts {
+		if cdt == dt {
+			return true
+		}
+	}
+	return false
+}
diff --git a/pkg/sfu/router.go b/pkg/sfu/router.go
index fa5a64e91..48c5d62cf 100644
--- a/pkg/sfu/router.go
+++ b/pkg/sfu/router.go
@@ -84,7 +84,6 @@ func (r *router) AddReceiver(receiver *webrtc.RTPReceiver, track *webrtc.TrackRe
 
 	publish := false
 	trackID := track.ID()
-	rid := track.RID()
 
 	buff, rtcpReader := r.bufferFactory.GetBufferPair(uint32(track.SSRC()))
 
@@ -164,17 +163,10 @@ func (r *router) AddReceiver(receiver *webrtc.RTPReceiver, track *webrtc.TrackRe
 			}
 			r.deleteReceiver(trackID, uint32(track.SSRC()))
 		})
-		if len(rid) == 0 || r.config.Simulcast.BestQualityFirst && rid == fullResolution ||
-			!r.config.Simulcast.BestQualityFirst && rid == quarterResolution {
-			publish = true
-		}
-	} else if r.config.Simulcast.BestQualityFirst && rid == fullResolution ||
-		!r.config.Simulcast.BestQualityFirst && rid == quarterResolution ||
-		!r.config.Simulcast.BestQualityFirst && rid == halfResolution {
 		publish = true
 	}
 
-	recv.AddUpTrack(track, buff)
+	recv.AddUpTrack(track, buff, r.config.Simulcast.BestQualityFirst)
 
 	buff.Bind(receiver.GetParameters(), buffer.Options{
 		MaxBitRate: r.config.MaxBandwidth,