Today at Google I/O, Google officially announced the forthcoming release of an open source, royalty-free video format called WebM. Using the VP8 codec that Google acquired from On2 last February, the format is backed by fellow browser makers Mozilla and Opera.

In April, rumors about the open sourcing of VP8 started to take off, but the implications of what VP8 — and now WebM — might mean has been somewhat clouded by the bigger battle between Apple and Adobe over HTML5, Flash and the future of mobile platforms.

While WebM is not currently part of the HTML5 spec, it will be added as a supported part of the <video> tag for the Chrome, Firefox and Opera browsers.

In addition to announcing WebM, Google also told the audience that WebM support will be coming to YouTube as part of its HTML5 experiment. All video that is in 720p or higher uploaded to YouTube from today onward will be encoded in WebM in addition to H.264.

One issue that has been raised in the debate over HTML5 and Flash, in terms of web video, is the issue of what video codecs HTML5 supports. Right now, HTML5 supports both H.264 and Xiph's Ogg Theora. While free for end users and for users who upload video to the web, H.264 is not a royalty-free technology. A consortium called the MPEG-LA, which includes Microsoft, Apple, Panasonic, Nokia, Sony and many other technology companies, oversees license requirements.

While in actual practice these licensing issues only impact people who are either creating an encoder or creating software to play back H.264 content, the issue has nonetheless been contentious, especially for companies like Mozilla and Opera who have ideological problems with using technology like H.264. Engadget's Nilay Patel and I discussed these issues at length with Dan Benjamin a few weeks ago on his podcast, "The Conversation."

With WebM, the royalty-free nature of the platform allows developers and software makers to use the technology without having to pay any licensing fees. Unlike other royalty-free formats, VP8 has the potential to provide real competition against H.264.

Adobe's Kevin Lynch spoke at Google I/O and announced that Adobe plans to build VP8 support into Flash and that WebM can be used with Adobe products like Dreamweaver. WebM is more than just video; it also supports features like embedded and selectable text and web fonts.

In the coming weeks and months, we expect to see more encoders and player plugins built to support WebM. The next step will be to see if hardware makers embrace WebM the same way they have embraced H.264. Accelerated video support for H.264 on a multitude of devices is one of the reasons that it has become the codec of choice for consumer video and a reason it has been so popular for video content creators.

Still, having alternatives is good. It's also important that open options be available on the web and that those options actually be compelling and usable. We think that WebM is a great move from Google and it has certainly added a new dimension to the growing discussion about the future of web video. The nightly builds of Chromium and Firefox now include WebM support. Opera builds with WebM support are available at labs.opera.com.

image courtesy of iStockphoto, Norebbo