It's not a big surprise that Microsoft and Apple were not among the many technology companies listed as initial supporters of Google's WebM project, a new initiative that the search giant describes as "a broadly-backed community effort to develop a world-class media format for the open web."

The announcement highlights a divide among the major makers of browsers and other web technologies that could determine the future of video on the web. Microsoft and Apple support H.264 as the standard video codec for HTML5, the next version of the web's underlying language. Firefox maker Mozilla, on the other hand, has steered clear of H.264, citing concerns over patents, and backing the Ogg Theora format instead.

With its announcement today, Google is providing an alternative by contributing its VP8 codec -- acquired through its $133 million purchase of On2 Technologies -- for use as part of the WebM project under a royalty-free license.

Which puts Microsoft in an awkward position.

Internet Explorer is still the most widely used browser on the web, but the company's absence from the official list of WebM supporters suggests it wasn't clued in beforehand, or perhaps chose not to be named. Whatever the case, Internet Explorer GM Dean Hachamovitch had this to say in a blog post: "In its HTML5 support, IE9 will support playback of H.264 video as well as VP8 video when the user has installed a VP8 codec on Windows."

That sentence deserves a careful read. H.264 will be supported natively in Internet Explorer 9, the next version of the browser, but with the reference to installing the VP8 codec in Windows, Hachamovitch is stopping short of promising the same native support for VP8 in the Microsoft browser. That's not to say that IE9 won't ultimately support VP8, but the Redmond company clearly isn't willing to go that far right now.

With the future of online video at stake, Microsoft would naturally be reluctant to jump on board with a project spearheaded by Google, its archrival. But in the long run, the writing may be on the wall.

"If it’s royalty free and it’s open, there’s no reason they can’t include that codec with Windows or IE," said Microsoft veteran Alex Castro, CEO of Seattle-based online video company Delve Networks, which announced its WebM support today. "I think inevitably open standards tend to win over the long term. It’s just a matter of how long it takes."

He noted that the rise of VP8 has the potential to drive adoption of native HTML5 video as an alternative to plugins such as Adobe Flash and Microsoft Silverlight.

Mozilla and Opera, in contrast to Microsoft, were enthusiastic in voicing their WebM support.

"The big news today is that WebM will join the list of open and freely usable Web formats, and video will finally become a first-class citizen of the Web," wrote Hakon Wium Lie, Opera's CTO. "This is a big deal, and the day will be remembered in the history of the Web."