I absolutely hate stumblevideo’s fade. It causes the video to skip, and drag.
So … I started playing around with javascript, and created a book marklet that will disable the fading, in and fading out.
javascript:(function(){dimAll = function(){}})();
You should be able to click and drag this link to your bookmark toolbark No Fade Stumble video
Just click it when you first load the page. Honestly I don’t know why they need it.
Or for the lazy people out there *like me* I’ve written an extension for firefox that does it for you every time the url has http://video.stumbleupon.com/ in it. nofadestumblevideo.xpi.