From 89a90abe18e8353ac796450cf24eee0020c405a6 Mon Sep 17 00:00:00 2001
From: Jo Turk <git@joturk.net>
Date: Sat, 26 Sep 2026 21:56:17 +0300
Subject: [PATCH] Filter OBU-padding

cases chrome to stall
---
 codecs/av1_packet.go      | 17 ++++++++++++-----
 codecs/av1_packet_test.go | 21 +++++++++++++++++++++
 2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/codecs/av1_packet.go b/codecs/av1_packet.go
index 797d4fe..af9e1f8 100644
--- a/codecs/av1_packet.go
+++ b/codecs/av1_packet.go
@@ -29,7 +29,7 @@ type AV1Payloader struct{}
 // 5.3. https://aomediacodec.github.io/av1-spec/av1-spec.pdf#page=39
 // Returns AV1 RTP packets https://aomediacodec.github.io/av1-rtp-spec/
 // The payload is fragmented into multiple packets, each packet is a valid AV1 RTP payload.
-// nolint:cyclop
+// nolint:cyclop,gocognit
 func (p *AV1Payloader) Payload(mtu uint16, payload []byte) (payloads [][]byte) {
 	// 2 is the minimum MTU for AV1 (aggregate header + 1 byte)
 	if mtu <= 1 || len(payload) == 0 {
@@ -72,6 +72,17 @@ func (p *AV1Payloader) Payload(mtu uint16, payload []byte) (payloads [][]byte) {
 			obuSize = len(payload) - offset
 		}
 
+		if obuSize > len(payload)-offset {
+			break
+		}
+
+		// padding carries no media and causes chromium to stall.
+		if obuHeader.Type == obu.OBUPadding {
+			offset += obuSize
+
+			continue
+		}
+
 		// Each RTP packet MUST NOT contain OBUs that belong to different temporal units.
 		// If a sequence header OBU is present in an RTP packet, then it SHOULD be the first OBU in the packet.
 		// https://aomediacodec.github.io/av1-rtp-spec/#5-packetization-rules
@@ -87,10 +98,6 @@ func (p *AV1Payloader) Payload(mtu uint16, payload []byte) (payloads [][]byte) {
 			currentPacketOBUHeader = obuHeader.ExtensionHeader
 		}
 
-		if obuSize > len(payload)-offset {
-			break
-		}
-
 		if len(currentOBUPayload) > 0 {
 			payloads, obusInPacket = p.appendOBUPayload(
 				payloads,
diff --git a/codecs/av1_packet_test.go b/codecs/av1_packet_test.go
index 5809c0e..3ad71c3 100644
--- a/codecs/av1_packet_test.go
+++ b/codecs/av1_packet_test.go
@@ -1166,6 +1166,27 @@ func TestAV1Payloader_HandleMTUBasedFragmentation(t *testing.T) {
 	testAV1TestRun(t, tests)
 }
 
+func TestAV1Payloader_Padding(t *testing.T) {
+	sequence := testAV1OBUPayload{
+		Header:  &obu.Header{Type: obu.OBUSequenceHeader, HasSizeField: true},
+		Payload: []byte{0x01},
+	}
+	frame := testAV1OBUPayload{
+		Header:  &obu.Header{Type: obu.OBUFrame, HasSizeField: true},
+		Payload: []byte{0x02},
+	}
+	padding := testAV1OBUPayload{
+		Header:  &obu.Header{Type: obu.OBUPadding, HasSizeField: true},
+		Payload: make([]byte, 8192),
+	}
+	payloader := &AV1Payloader{}
+
+	assert.Empty(t, payloader.Payload(6, padding.Marshal()))
+	assert.Equal(t, [][]byte{{0x28, 0x02, 0x08, 0x01, 0x30, 0x02}},
+		payloader.Payload(6, (testAV1MultiOBUsPayload{padding, sequence, padding, frame, padding}).Marshal()),
+	)
+}
+
 func TestAV1Payloader_TemporalDelimiter(t *testing.T) {
 	tests := []testAV1Tests{
 		{