[Cleo]

This is the code I'm using.

<div id="player"></div>
<script type="text/javascript" src="swfobject.js"></script>
<script type="text/javascript">
var so = new SWFObject('player.swf','mpl','289','238','9');
so.addParam('allowscriptaccess','always');
so.addParam('allowfullscreen','true');
so.addParam('flashvars','file=small.mp4&image=cover.png');
so.write('player');
</script>

I don't convert my mp4 but link to it using the above code.

To play mp4 files on your PC without putting them in a flash player you would need something like QuickTime to play them.