From 40ff0605e5fe480488bb1f399e9433d509f909fc Mon Sep 17 00:00:00 2001
From: Federico Pereira <lord.basex@gmail.com>
Date: Wed, 7 Oct 2026 16:19:26 -0300
Subject: [PATCH] Always send PictureID 0 in VP8Payloader

With EnablePictureID, the frame whose PictureID is 0 was sent without
the X and I bits, so it carried no PictureID at all. The ID wraps every
32768 frames (9 min 6 s at 60 fps), so a long stream had one frame
without a PictureID among frames that had one. Chrome then lost the
frame references and dropped every frame until the next keyframe: a
freeze every 546 s, with no lost packets, NACKs or PLIs.

Frame 0 now carries a 7-bit PictureID like every other ID under 128.
---
 codecs/vp8_packet.go      |  1 -
 codecs/vp8_packet_test.go | 23 +++++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/codecs/vp8_packet.go b/codecs/vp8_packet.go
index 569853c..f080532 100644
--- a/codecs/vp8_packet.go
+++ b/codecs/vp8_packet.go
@@ -39,7 +39,6 @@ func (p *VP8Payloader) Payload(mtu uint16, payload []byte) [][]byte { //nolint:c
 	usingHeaderSize := vp8HeaderSize
 	if p.EnablePictureID {
 		switch {
-		case p.pictureID == 0:
 		case p.pictureID < 128:
 			usingHeaderSize = vp8HeaderSize + 2
 		default:
diff --git a/codecs/vp8_packet_test.go b/codecs/vp8_packet_test.go
index eb2d6cf..7b97946 100644
--- a/codecs/vp8_packet_test.go
+++ b/codecs/vp8_packet_test.go
@@ -143,6 +143,29 @@ func TestVP8Payloader_Payload(t *testing.T) {
 				},
 			},
 		},
+		"WithPictureID_wrap": {
+			payloader: VP8Payloader{
+				EnablePictureID: true,
+				pictureID:       0x7FFF,
+			},
+			mtu: 6,
+			payload: [][]byte{
+				{0x90, 0x90},
+				{0x91, 0x91},
+				{0x92, 0x92},
+			},
+			expected: [][][]byte{
+				{
+					{0x90, 0x80, 0xFF, 0xFF, 0x90, 0x90},
+				},
+				{
+					{0x90, 0x80, 0x00, 0x91, 0x91},
+				},
+				{
+					{0x90, 0x80, 0x01, 0x92, 0x92},
+				},
+			},
+		},
 	}
 	for name, testCase := range testCases {
 		t.Run(name, func(t *testing.T) {