From ce4ea105519f739a9619f4d7511be082cfb16f4f Mon Sep 17 00:00:00 2001
From: Alex P <dtk077@gmail.com>
Date: Tue, 4 Nov 2025 10:40:35 +0200
Subject: [PATCH] fix: handle audio track recreation to prevent microphone
 failures

When browsers recreate audio tracks during long sessions, the backend
now properly handles the new track instead of ignoring it. Old track
handlers detect when they've been superseded and exit cleanly to
prevent goroutine leaks.
---
 audio.go | 30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/audio.go b/audio.go
index af51d16a..374a98b7 100644
--- a/audio.go
+++ b/audio.go
@@ -21,7 +21,7 @@ var (
 	activeConnections  atomic.Int32
 	audioLogger        zerolog.Logger
 	currentAudioTrack  *webrtc.TrackLocalStaticSample
-	inputTrackHandling atomic.Bool
+	currentInputTrack  atomic.Pointer[string]
 	audioOutputEnabled atomic.Bool
 	audioInputEnabled  atomic.Bool
 )
@@ -152,13 +152,9 @@ func setAudioTrack(audioTrack *webrtc.TrackLocalStaticSample) {
 }
 
 func setPendingInputTrack(track *webrtc.TrackRemote) {
-	audioMutex.Lock()
-	defer audioMutex.Unlock()
-
-	// Start input track handler only once per WebRTC session
-	if inputTrackHandling.CompareAndSwap(false, true) {
-		go handleInputTrackForSession(track)
-	}
+	trackID := track.ID()
+	currentInputTrack.Store(&trackID)
+	go handleInputTrackForSession(track)
 }
 
 // SetAudioOutputEnabled enables or disables audio output
@@ -202,22 +198,32 @@ func SetAudioInputEnabled(enabled bool) error {
 // handleInputTrackForSession runs for the entire WebRTC session lifetime
 // It continuously reads from the track and sends to whatever relay is currently active
 func handleInputTrackForSession(track *webrtc.TrackRemote) {
-	defer inputTrackHandling.Store(false)
+	myTrackID := track.ID()
 
 	audioLogger.Debug().
 		Str("codec", track.Codec().MimeType).
-		Str("track_id", track.ID()).
+		Str("track_id", myTrackID).
 		Msg("starting session-lifetime track handler")
 
 	for {
+		// Check if we've been superseded by a new track
+		currentTrackID := currentInputTrack.Load()
+		if currentTrackID != nil && *currentTrackID != myTrackID {
+			audioLogger.Debug().
+				Str("my_track_id", myTrackID).
+				Str("current_track_id", *currentTrackID).
+				Msg("audio track handler exiting - superseded by new track")
+			return
+		}
+
 		// Read RTP packet (must always read to keep track alive)
 		rtpPacket, _, err := track.ReadRTP()
 		if err != nil {
 			if err == io.EOF {
-				audioLogger.Debug().Msg("audio track ended")
+				audioLogger.Debug().Str("track_id", myTrackID).Msg("audio track ended")
 				return
 			}
-			audioLogger.Warn().Err(err).Msg("failed to read RTP packet")
+			audioLogger.Warn().Err(err).Str("track_id", myTrackID).Msg("failed to read RTP packet")
 			continue
 		}