A little less than a month ago, Google announced that it was going full steam ahead with its WebM video format and dropping H.264 support from Chrome. Now, Microsoft has released an extension that allows Chrome, once again, to play H.264 video embedded using the HTML5 <video> tag.
Microsoft says in its blog post, "At Microsoft we respect that Windows customers want the best experience of the web including the ability to enjoy the widest range of content available on the Internet in H.264 format." The extension, available here, requires Chrome 8.0 and Windows 7. It "parses HTML5 pages and replaces Video tags with a call to the Windows Media Player plug-in so that the content can be played in the browser." I believe that means hardware acceleration is on the menu, too.
As Microsoft points out, pre-release versions of Internet Explorer 9 already have H.264 support out of the box, but that browser will also support WebM through third-party plug-ins. Still, HTML5 video codec standardization remains very much an issue. This chart on Wikipedia shows that no single codec is yet supported by default in all popular modern browsers—namely IE, Firefox, Chrome, Safari, and Opera.