Mozilla, the makers of Firefox, refuse to support the MP4/H.264 standard because it isn’t open-source and free from licensing constraints. Without Ogg, Firefox’s HTML5 video is rendered useless and requires a Flash-based fallback system. However, Firefox’s handling of the video element breaks the fallback mechanism. A scripted solution is required.
Here’s a simple script that will detect whether HTML 5 video is supported in the browser, and if it is, will check to see if this is Firefox. If yes, it deletes the specified video element but leaves the Flash fallback in its place.