As well as providing a download link, you could (and probably should) embed a Flash fallback player that can play the MP4 video file.
Yes, I’m afraid that despite all this great work with HTML5 and native multimedia, you still may want to resort to embedding Flash content, just for those older browsers that can’t cope. That said, you do want to reach as many users as possible, so at least there’s an option!
In the past, you could embed your Flash fallback player and video into your Web page using either the object element or the embed element, but neither was strictly valid HTML, because neither was in the specification.
The HTML5 specification does contain the embed and object elements, so at least now they’re ...