Splash image (first frame) not visible in Opera, Firefox until click 'play', ok in Safari and Chrome (on Mac OS X)

On Mac OS X 10.8.5

Not sure whether to call this a bug, feature request, or support request

The first frame (splash image) of the following H.264 mp4 video does not appear on 1st page load on all browsers: Video: Demonstration of NetBeans IDE prompting on an OOE IMenuItem encapsulation of a Drupal menu item in object-oriented PHP.

It's ok on the following browsers:

- Safari 6.1.1 (OK)
- Chrome 32.0.1700.107 (OK)

But on these browsers all one sees is a black background behind the play button, until the video PLAY button is clicked and the video starts to play:

- Firefox 27.0.1
- Opera 20.0

In both cases, after playing through, the video returns to the 1st frame (does not stay with the last frame) and thereafter the "splash" screen first frame is visible.

Q: Is there in any case a way with MediaElement to specify a chosen splash image ?