Osciloscope integrated but video exported is broken

src/hooks/useOfflineVideoExport.ts

@@ -351,7 +351,7 @@ export const useOfflineVideoExport = () => {
   };
 };
 
-// Memory-efficient muxing using real-time playback
+// Improved muxing with better synchronization
 async function muxAudioVideo(
   videoBlob: Blob,
   audioFile: File,
@@ -367,9 +367,9 @@ async function muxAudioVideo(
     
     video.src = videoUrl;
     video.muted = true;
-    video.playbackRate = 4; // Speed up playback
+    video.playbackRate = 1; // Normal playback speed
     audio.src = audioUrl;
-    audio.playbackRate = 4;
+    audio.playbackRate = 1;
 
     const cleanup = () => {
       URL.revokeObjectURL(videoUrl);
@@ -428,21 +428,39 @@ async function muxAudioVideo(
         reject(new Error('Muxing failed'));
       };
 
+      let lastVideoTime = 0;
       const drawLoop = () => {
-        if (video.ended || audio.ended) {
-          setTimeout(() => recorder.stop(), 100);
+        if (video.paused || video.ended) {
+          if (video.ended || audio.ended) {
+            setTimeout(() => recorder.stop(), 100);
+            return;
+          }
+          requestAnimationFrame(drawLoop);
           return;
         }
-        ctx.drawImage(video, 0, 0);
+        
+        // Only draw when video has progressed
+        if (video.currentTime !== lastVideoTime) {
+          lastVideoTime = video.currentTime;
+          ctx.drawImage(video, 0, 0);
+        }
         requestAnimationFrame(drawLoop);
       };
 
       recorder.start(100);
+      
+      // Ensure both start at the same time
       video.currentTime = 0;
       audio.currentTime = 0;
-      video.play();
-      audio.play();
-      drawLoop();
+      
+      // Wait for both to be ready to play
+      Promise.all([video.play(), audio.play()]).then(() => {
+        drawLoop();
+      }).catch(err => {
+        console.error('Playback failed:', err);
+        cleanup();
+        reject(err);
+      });
     }).catch(err => {
       cleanup();
       console.warn('Muxing failed, returning video only:', err);