Update app.py

app.py

@@ -930,9 +930,9 @@ window.recorder = null;
 
 function record_video() {
   try {
-  if (BABYLON.VideoRecorder.IsSupported(BABYLON.Engine) && (recorder == null || !recorder.isRecording) ) {
+  if (BABYLON.VideoRecorder.IsSupported(BABYLON.Engine.LastCreatedScene.getEngine()) && (recorder == null || !recorder.isRecording) ) {
     if (recorder == null) {
-        recorder = new BABYLON.VideoRecorder(BABYLON.Engine, { mimeType:'video/mp4', fps:25, /*audioTracks: mediaStreamDestination.stream.getAudioTracks()*/ });
+        recorder = new BABYLON.VideoRecorder(BABYLON.Engine.LastCreatedScene.getEngine(), { mimeType:'video/mp4', fps:25, /*audioTracks: mediaStreamDestination.stream.getAudioTracks()*/ });
     }
     recorder.startRecording('video.mp4', 60*60);
   }