The trailer used in the examples below is Sintel, © copyright Blender Foundation | durian.blender.org
In the example below the WVideo class is used with a WImage (a static JPEG image) as fallback. The video will play on browsers (like Firefox, Chrome and Safari) that support MP4 or OGV video streams natively (using HTML <video>), but the video control will show the image on other browsers (Internet Explorer, Opera, ...).
For browsers that support HTML <video>, the video below looks exactly like the one above. On other browsers, the player below falls back to a Flash player to play the video. If flash is not supported on your system, a static image is shown.
Any Flash-based video player can do the job. In the example below the FLV Player is used as fallback for HTML5 video.
You may also choose to simply rely on Flash to play the video. In the menu item WFlashObject you can find an example.