HTML5 is a new set of standards that allows you to embed videos that are viewable across multiple platforms and devices. If this is your first time embedding video on your webpage using HTML5, you will notice that the <video> tag now supports multiple video formats. HTML5 video uses the MP4, WebM and Ogg formats. While most servers will come configured for MP4, other servers (Mamp and Wamp included) will balk on WebM and OGG if it’s not configured correctly. NOTE: If you are on ServerGrove shared hosting, the mime types are already configured and you should not have to worry about this stuff.
If you are using the Apache Webserver you will need to add the following code to your httpd.conf file or to an .htaccess file in the directory where your video files are.
AddType video/ogg .ogv AddType video/mp4 .mp4 AddType video/webm .webm
More information on the HTML5 video player can be found here: http://www.html5rocks.com/en/tutorials/video/basics/