Adobe has released an easy-to-use, totally CSS-customizable solution that shifts gracefully from the HTML5 <video> tag to the Flash Player when the tag isn't supported. The shift takes place regardless of the screen -- from phone to monitor to TV.
HTML5 Video Player widget, works with or without Dreamweaver CS5. Code generated from widget plays video in best possible player for the requested platform using a range of video codecs. Based on Kaltura open source library, HTML5 Video Player widget is fully cross-browser compatible with support for IE, Firefox, Safari, Chrome, and Opera.
You can run Adobe Widget Browser directly from within Dreamweaver and, once you've set it up, insert the generated code and files for HTML5 Video Player widget with point-and-click simplicity. But if you're not a Dreamweaver user, you can also download Widget Browser independently. (You'll need to install Adobe AIR)
Download: Adobe Widget Browser