--- a/dom/media/test/test_streams_autoplay.html
+++ b/dom/media/test/test_streams_autoplay.html
@@ -15,17 +15,21 @@ SimpleTest.waitForExplicitFinish();
 
 var media = getPlayableVideo(gSmallTests);
 
 if (media == null) {
   todo(false, "No media supported.");
   SimpleTest.finish();
 } else {
   v1.src = media.name;
-  v2.srcObject = v1.mozCaptureStream();
+  v1.preload = 'metadata';
+  v1.onloadedmetadata = function() {
+    v2.srcObject = v1.mozCaptureStream();
+  };
+
   var onPlayingEventFired = false;
 
   v2.onplaying = function() {
     if(!onPlayingEventFired) {
       onPlayingEventFired = true;
       ok(true, "playback started");
       SimpleTest.finish();
     }