From e5dae16da1187585894d0b2cfa9912fb1db0e88c Mon Sep 17 00:00:00 2001
From: Juliusz Chroboczek <jch@irif.fr>
Date: Tue, 28 Apr 2020 20:15:24 +0200
Subject: [PATCH] Rate-limit PLI.

---
 client.go | 12 +++++++++++-
 group.go  |  1 +
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/client.go b/client.go
index c5a5331..d70c16b 100644
--- a/client.go
+++ b/client.go
@@ -511,7 +511,7 @@ func rtcpListener(g *group, conn *downConnection, track *downTrack, s *webrtc.RT
 		for _, p := range ps {
 			switch p := p.(type) {
 			case *rtcp.PictureLossIndication:
-				err := sendPLI(conn.remote.pc, p.MediaSSRC)
+				err := conn.remote.sendPLI(track.remote)
 				if err != nil {
 					log.Printf("sendPLI: %v", err)
 				}
@@ -585,6 +585,16 @@ func updateUpBitrate(up *upConnection) {
 	}
 }
 
+func (up *upConnection) sendPLI(track *upTrack) error {
+	last := atomic.LoadUint64(&track.lastPLI)
+	now := msSinceEpoch()
+	if now >= last && now - last < 200 {
+		return nil
+	}
+	atomic.StoreUint64(&track.lastPLI, now)
+	return sendPLI(up.pc, track.track.SSRC())
+}
+
 func sendPLI(pc *webrtc.PeerConnection, ssrc uint32) error {
 	return pc.WriteRTCP([]rtcp.Packet{
 		&rtcp.PictureLossIndication{MediaSSRC: ssrc},
diff --git a/group.go b/group.go
index 89eb56e..378f587 100644
--- a/group.go
+++ b/group.go
@@ -24,6 +24,7 @@ type upTrack struct {
 	track      *webrtc.Track
 	list       *packetlist.List
 	maxBitrate uint64
+	lastPLI    uint64
 
 	mu    sync.Mutex
 	local []*downTrack