From 552151fece0f398152112e35cb2c32fc0550e2c6 Mon Sep 17 00:00:00 2001
From: zarazaex69 <zarazaex@tuta.io>
Date: Wed, 27 May 2026 10:55:37 +0300
Subject: [PATCH] fix(videochannel): force VP8 keyframes and drop bad frames

---
 go.mod                                       |  2 +-
 go.sum                                       |  4 +--
 internal/transport/videochannel/gocodec.go   | 10 +++---
 internal/transport/videochannel/transport.go | 33 ++++++--------------
 4 files changed, 18 insertions(+), 31 deletions(-)

diff --git a/go.mod b/go.mod
index 9cfce72..36deac0 100644
--- a/go.mod
+++ b/go.mod
@@ -3,7 +3,7 @@ module github.com/openlibrecommunity/olcrtc
 go 1.26.3
 
 require (
-	codeberg.org/rape4me/kc v0.0.0-20260527043314-71657a097a6f
+	codeberg.org/rape4me/kc v0.0.0-20260527074346-4cb2a45790c2
 	github.com/google/uuid v1.6.0
 	github.com/gorilla/websocket v1.5.4-0.20250319132907-e064f32e3674
 	github.com/livekit/protocol v1.46.0
diff --git a/go.sum b/go.sum
index 131aebf..eb37156 100644
--- a/go.sum
+++ b/go.sum
@@ -7,8 +7,8 @@ buf.build/go/protoyaml v0.7.0/go.mod h1:+a0cavd0uMvirb87xdu2ZMMmjlIQoiH/N2Ich5MG
 cel.dev/expr v0.25.2 h1:K6j46C81hXtZQfuX60cVWQFBJahKSE2gfRbNuvr5bFs=
 cel.dev/expr v0.25.2/go.mod h1:hrXvqGP6G6gyx8UAHSHJ5RGk//1Oj5nXQ2NI02Nrsg4=
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
-codeberg.org/rape4me/kc v0.0.0-20260527043314-71657a097a6f h1:amyzfF9+4jCUKJndW336YHbj3FiaWs/qkJqOgUyreCA=
-codeberg.org/rape4me/kc v0.0.0-20260527043314-71657a097a6f/go.mod h1:ooInikVAZhJE+m+gHIekq52ZFkUPcCZAvY4u/m2M/V0=
+codeberg.org/rape4me/kc v0.0.0-20260527074346-4cb2a45790c2 h1:u7QorW08YOZGj86cubeGpiwm+d0tMKa0e7syiBkO2eo=
+codeberg.org/rape4me/kc v0.0.0-20260527074346-4cb2a45790c2/go.mod h1:ooInikVAZhJE+m+gHIekq52ZFkUPcCZAvY4u/m2M/V0=
 dario.cat/mergo v1.0.0 h1:AGCNq9Evsj31mOgNPcLyXc+4PNABt905YmuqPYYpBWk=
 dario.cat/mergo v1.0.0/go.mod h1:uNxQE+84aUszobStD9th8a29P2fMDhsBdgRYvZOxGmk=
 github.com/Azure/go-ansiterm v0.0.0-20230124172434-306776ec8161 h1:L/gRVlceqvL25UVaW/CKtUDjefjrs0SPonmDGUVOYP0=
diff --git a/internal/transport/videochannel/gocodec.go b/internal/transport/videochannel/gocodec.go
index 6303c64..0ef463d 100644
--- a/internal/transport/videochannel/gocodec.go
+++ b/internal/transport/videochannel/gocodec.go
@@ -20,8 +20,10 @@ type goEncoder struct {
 }
 
 func newGoEncoder(width, height, _ int) *goEncoder {
+	enc := vp8.NewEncoder(width, height, 63)
+	enc.SetKeyInterval(1)
 	return &goEncoder{
-		enc:       vp8.NewEncoder(width, height, 10),
+		enc:       enc,
 		width:     width,
 		height:    height,
 		frameSize: width * height,
@@ -74,12 +76,10 @@ func (d *goDecoder) PushSample(sample []byte) error {
 	}
 	frame, err := d.dec.Decode(sample)
 	if err != nil {
-		// Inter-frame arrived before any keyframe (e.g. SFU started forwarding
-		// mid-GOP). Drop silently; the next keyframe will reset the reference.
 		if errors.Is(err, vp8.ErrNoReference) {
-			return nil
+			return nil // skip inter-frames until keyframe arrives
 		}
-		return fmt.Errorf("vp8 decode: %w", err)
+		return nil // skip undecodable frames (e.g. from other participants)
 	}
 	gray := frame.Grayscale()
 	select {
diff --git a/internal/transport/videochannel/transport.go b/internal/transport/videochannel/transport.go
index 1c3d329..ed9abcf 100644
--- a/internal/transport/videochannel/transport.go
+++ b/internal/transport/videochannel/transport.go
@@ -88,9 +88,6 @@ type streamTransport struct {
 	remoteRole      byte
 	bindingToken    uint32
 	runCtx          context.Context //nolint:containedctx,lll // long-lived context drives idle-frame loops bound to this transport's lifetime
-
-	idleFrame   []byte
-	idleFrameMu sync.Mutex
 }
 
 // New creates a visual videochannel transport backed by a carrier engine.
@@ -388,28 +385,18 @@ func (p *streamTransport) Features() transport.Features {
 }
 
 func (p *streamTransport) writeIdleFrame(enc *goEncoder, frameDuration time.Duration) {
-	p.idleFrameMu.Lock()
-	cached := p.idleFrame
-	p.idleFrameMu.Unlock()
-
-	if cached == nil {
-		rawFrame, err := p.renderFrame(nil)
-		if err != nil {
-			logger.Debugf("videochannel render idle error: %v", err)
-			return
-		}
-		sample, err := enc.EncodeFrame(rawFrame)
-		if err != nil {
-			logger.Warnf("videochannel encoder idle error: %v", err)
-			return
-		}
-		p.idleFrameMu.Lock()
-		p.idleFrame = sample
-		p.idleFrameMu.Unlock()
-		cached = sample
+	rawFrame, err := p.renderFrame(nil)
+	if err != nil {
+		logger.Debugf("videochannel render idle error: %v", err)
+		return
+	}
+	sample, err := enc.EncodeFrame(rawFrame)
+	if err != nil {
+		logger.Warnf("videochannel encoder idle error: %v", err)
+		return
 	}
 
-	_ = p.track.WriteSample(media.Sample{Data: cached, Duration: frameDuration})
+	_ = p.track.WriteSample(media.Sample{Data: sample, Duration: frameDuration})
 }
 
 func (p *streamTransport) writePayloadFrame(enc *goEncoder, payload []byte, frameDuration time.Duration) {