Add latency monitor to prevent buffer accumulation

- Monitor video buffer every 2 seconds
- If more than 0.5s behind live edge, skip to catch up
- Prevents gradual latency increase over time

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

index.html

@@ -717,6 +717,7 @@
         let micEnabled = false;
         let robotMuted = true;
         let audioSender = null;
+        let latencyMonitorId = null;
 
         // Export functions
         window.loginToHuggingFace = loginToHuggingFace;
@@ -916,7 +917,14 @@
 
             peerConnection.ontrack = (e) => {
                 if (e.track.kind === 'video') {
-                    document.getElementById('remoteVideo').srcObject = e.streams[0];
+                    const video = document.getElementById('remoteVideo');
+                    video.srcObject = e.streams[0];
+                    // Low-latency optimizations
+                    video.playsInline = true;
+                    if ('requestVideoFrameCallback' in video) {
+                        // Start latency monitoring
+                        startLatencyMonitor(video);
+                    }
                 }
                 if (e.track.kind === 'audio') {
                     const audioEl = document.getElementById('remoteAudio');
@@ -981,7 +989,29 @@
             }
         }
 
+        // Latency monitor - catch up to live if buffer grows too large
+        function startLatencyMonitor(video) {
+            if (latencyMonitorId) clearInterval(latencyMonitorId);
+
+            latencyMonitorId = setInterval(() => {
+                if (!video.srcObject || video.paused) return;
+
+                const buffered = video.buffered;
+                if (buffered.length > 0) {
+                    const bufferedEnd = buffered.end(buffered.length - 1);
+                    const lag = bufferedEnd - video.currentTime;
+
+                    // If more than 0.5s behind live edge, catch up
+                    if (lag > 0.5) {
+                        console.log(`Latency correction: was ${lag.toFixed(2)}s behind`);
+                        video.currentTime = bufferedEnd - 0.1;
+                    }
+                }
+            }, 2000); // Check every 2 seconds
+        }
+
         function stopStream() {
+            if (latencyMonitorId) clearInterval(latencyMonitorId);
             if (stateRefreshInterval) clearInterval(stateRefreshInterval);
             if (peerConnection) peerConnection.close();
             if (dataChannel) dataChannel.close();