From 6939fe3c86e5be04ec446e4e4f802f2998e3f9bf Mon Sep 17 00:00:00 2001
From: Abhishek <princeabhi.work@gmail.com>
Date: Wed, 2 Sep 2026 13:15:03 +0530
Subject: [PATCH] Fix pacer activity tracking without RTP header extensions
 (#4831)

---
 pkg/sfu/pacer/base.go      |  5 +---
 pkg/sfu/pacer/base_test.go | 51 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+), 4 deletions(-)
 create mode 100644 pkg/sfu/pacer/base_test.go

diff --git a/pkg/sfu/pacer/base.go b/pkg/sfu/pacer/base.go
index 96e3be250..94d64d222 100644
--- a/pkg/sfu/pacer/base.go
+++ b/pkg/sfu/pacer/base.go
@@ -85,6 +85,7 @@ func (b *Base) SendPacket(p *Packet) (int, error) {
 		return 0, err
 	}
 
+	b.lastPacketSentAt.Store(mono.UnixNano())
 	return written, nil
 }
 
@@ -103,8 +104,6 @@ func (b *Base) patchRTPHeaderExtensions(p *Packet) error {
 		if err = p.Header.SetExtension(p.AbsSendTimeExtID, absSendTimeBytes); err != nil {
 			return err
 		}
-
-		b.lastPacketSentAt.Store(sendingAt.UnixNano())
 	}
 
 	packetSize := p.HeaderSize + len(p.Payload)
@@ -127,8 +126,6 @@ func (b *Base) patchRTPHeaderExtensions(p *Packet) error {
 		if err = p.Header.SetExtension(p.TransportWideExtID, twccExtBytes); err != nil {
 			return err
 		}
-
-		b.lastPacketSentAt.Store(sendingAt.UnixNano())
 	}
 
 	b.ProbeObserver.RecordPacket(packetSize, p.IsRTX, p.ProbeClusterId, p.IsProbe)
diff --git a/pkg/sfu/pacer/base_test.go b/pkg/sfu/pacer/base_test.go
new file mode 100644
index 000000000..e046a98e2
--- /dev/null
+++ b/pkg/sfu/pacer/base_test.go
@@ -0,0 +1,51 @@
+// Copyright 2026 LiveKit, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package pacer
+
+import (
+	"testing"
+	"time"
+
+	"github.com/livekit/protocol/logger"
+	"github.com/livekit/protocol/utils/mono"
+	"github.com/pion/rtp"
+	"github.com/stretchr/testify/require"
+)
+
+type testTrackLocalWriter struct{}
+
+func (testTrackLocalWriter) WriteRTP(header *rtp.Header, payload []byte) (int, error) {
+	return header.MarshalSize() + len(payload), nil
+}
+
+func (testTrackLocalWriter) Write(b []byte) (int, error) {
+	return len(b), nil
+}
+
+func TestBaseSendPacketTracksActivityWithoutHeaderExtensions(t *testing.T) {
+	b := NewBase(logger.GetLogger(), nil)
+	b.lastPacketSentAt.Store(mono.UnixNano() - int64(time.Second))
+
+	p := &Packet{
+		Header:      &rtp.Header{Version: 2},
+		HeaderSize: 12,
+		Payload:     []byte{1, 2, 3, 4},
+		WriteStream: testTrackLocalWriter{},
+	}
+
+	_, err := b.SendPacket(p)
+	require.NoError(t, err)
+	require.Less(t, b.TimeSinceLastSentPacket(), 100*time.Millisecond)
+}