From ddece1fbb0ea6c3fa2ec7437d98faea82d651ca9 Mon Sep 17 00:00:00 2001
From: Raja Subramanian <raja.gobi@tutanota.com>
Date: Mon, 8 Apr 2024 11:29:55 +0530
Subject: [PATCH] Use aarival time in cached packets. (#2633)

---
 pkg/sfu/buffer/buffer.go | 29 ++++++++++++++---------------
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/pkg/sfu/buffer/buffer.go b/pkg/sfu/buffer/buffer.go
index 70f9940b3..8b7678671 100644
--- a/pkg/sfu/buffer/buffer.go
+++ b/pkg/sfu/buffer/buffer.go
@@ -301,9 +301,10 @@ func (b *Buffer) Write(pkt []byte) (n int, err error) {
 		return
 	}
 
+	now := time.Now()
 	if b.twcc != nil && b.twccExt != 0 && !b.closed.Load() {
 		if ext := rtpPacket.GetExtension(b.twccExt); ext != nil {
-			b.twcc.Push(rtpPacket.SSRC, binary.BigEndian.Uint16(ext[0:2]), time.Now().UnixNano(), rtpPacket.Marker)
+			b.twcc.Push(rtpPacket.SSRC, binary.BigEndian.Uint16(ext[0:2]), now.UnixNano(), rtpPacket.Marker)
 		}
 	}
 
@@ -316,7 +317,7 @@ func (b *Buffer) Write(pkt []byte) (n int, err error) {
 			return
 		}
 
-		pb.writeRTX(&rtpPacket)
+		pb.writeRTX(&rtpPacket, now)
 		return
 	}
 
@@ -325,7 +326,7 @@ func (b *Buffer) Write(pkt []byte) (n int, err error) {
 		copy(packet, pkt)
 		b.pPackets = append(b.pPackets, pendingPacket{
 			packet:      packet,
-			arrivalTime: time.Now(),
+			arrivalTime: now,
 		})
 		b.Unlock()
 		return
@@ -353,11 +354,11 @@ func (b *Buffer) SetPrimaryBufferForRTX(primaryBuffer *Buffer) {
 		if rtpPacket.Padding && len(rtpPacket.Payload) == 0 {
 			continue
 		}
-		primaryBuffer.writeRTX(&rtpPacket)
+		primaryBuffer.writeRTX(&rtpPacket, pp.arrivalTime)
 	}
 }
 
-func (b *Buffer) writeRTX(rtxPkt *rtp.Packet) (n int, err error) {
+func (b *Buffer) writeRTX(rtxPkt *rtp.Packet, arrivalTime time.Time) (n int, err error) {
 	b.Lock()
 	defer b.Unlock()
 	if !b.bound {
@@ -368,19 +369,18 @@ func (b *Buffer) writeRTX(rtxPkt *rtp.Packet) (n int, err error) {
 		b.rtxPktBuf = make([]byte, bucket.MaxPktSize)
 	}
 
-	videoPkt := *rtxPkt
-	videoPkt.PayloadType = b.payloadType
-	videoPkt.SequenceNumber = binary.BigEndian.Uint16(rtxPkt.Payload[:2])
-	videoPkt.SSRC = b.mediaSSRC
-	videoPkt.Payload = rtxPkt.Payload[2:]
-	n, err = videoPkt.MarshalTo(b.rtxPktBuf)
-
+	repairedPkt := *rtxPkt
+	repairedPkt.PayloadType = b.payloadType
+	repairedPkt.SequenceNumber = binary.BigEndian.Uint16(rtxPkt.Payload[:2])
+	repairedPkt.SSRC = b.mediaSSRC
+	repairedPkt.Payload = rtxPkt.Payload[2:]
+	n, err = repairedPkt.MarshalTo(b.rtxPktBuf)
 	if err != nil {
-		b.logger.Errorw("could not marshal repaired packet", err, "ssrc", b.mediaSSRC, "sn", videoPkt.SequenceNumber)
+		b.logger.Errorw("could not marshal repaired packet", err, "ssrc", b.mediaSSRC, "sn", repairedPkt.SequenceNumber)
 		return
 	}
 
-	b.calc(b.rtxPktBuf[:n], &videoPkt, time.Now(), true)
+	b.calc(b.rtxPktBuf[:n], &repairedPkt, arrivalTime, true)
 	return
 }
 
@@ -664,7 +664,6 @@ func (b *Buffer) updateStreamState(p *rtp.Packet, arrivalTime time.Time) RTPFlow
 }
 
 func (b *Buffer) processHeaderExtensions(p *rtp.Packet, arrivalTime time.Time, isRTX bool) {
-
 	if b.audioLevelExt != 0 && !isRTX {
 		if !b.latestTSForAudioLevelInitialized {
 			b.latestTSForAudioLevelInitialized = true