--- a/dom/media/test/test_bug879717.html
+++ b/dom/media/test/test_bug879717.html
@@ -41,17 +41,16 @@ var startTest = function(media, token) {
   manager.started(token);
 
   // File playback
   var v1 = document.createElement("video");
   v1.autoplay = true;
 
   // Captured file playback
   var v2 = document.createElement("video");
-  v2.autoplay = true;
 
   // Stream playback
   var v3 = document.createElement("video");
   v3.autoplay = true;
 
   v1.gotLoadeddata = false;
   v2.gotLoadeddata = false;
   v3.gotLoadeddata = false;
@@ -115,16 +114,21 @@ var startTest = function(media, token) {
   v3.onended = onended;
 
   document.body.appendChild(v1);
   document.body.appendChild(v2);
   document.body.appendChild(v3);
 
   v1.src = media.name;
   v2.src = media.name;
-  v3.srcObject = v2.mozCaptureStreamUntilEnded();
+  v2.preload = 'metadata';
+
+  v2.addEventListener('loadedmetadata', function () {
+    v3.srcObject = v2.mozCaptureStreamUntilEnded();
+    v2.play();
+  });
 }
 
 manager.runTests(getPlayableVideos(gSmallTests), startTest);
 </script>
 </pre>
 </body>
 </html>