WebM, the open video standard introduced at Google's recent I/O developer conference, is now coming to Firefox 4. According Mozilla's Robert O'Callahan, the key sticking point was making sure that the new WebM codec licensing was compatible with GPL - an open-source licensing type that allows users to copy, modify and redistribute software free of charge as long as modifications made are shared with the community.

That issue has now been addressed, allowing Mozilla to support the codec in its Firefox Web browser.

What's WebM?

The WebM video format is based on the VP8 video codec, something Google acquired last year from On2 Technologies, a New York-based video compression developer, for $106.5 million. At that time, Google announced it intended to use the codec technology it now owned to "make the overall Web experience better for users."

Since the acquisition, Google has open-sourced the codec, fixed the licensing issues (as noted above) and added WebM support into its own Web browser, Google Chrome, the latter taking place just last week.

WebM is an alternative to the H.264 codec, which is currently used by Apple to display video on the iPad and iPhone and is supported within Adobe's Flash player, among other things. Although H.264 is available royalty-free right now, it's owned by the MPEG LA consortium, a group that has announced the codec will only remain royalty-free until Dec. 31, 2015. After this license term is up, it's suspected that there will be charges for its use going forward.

Where to Find It

One of the first sites to implement WebM, was, of course, Google's own video property, YouTube. To utilize the new codec, which is still in testing, one can enable the "HTML5 experiment" following instructions from the WebM's project page. In addition to Google Chrome and now Firefox, Microsoft too has announced support for WebM in its upcoming Web browser, IE9, after an end user installs the necessary codec (VP8). Apple has so far made no comment on whether or not its Safari browser will do the same.

As for Mozilla, WebM is now available in the Firefox nightly builds, the experimental builds that will, in time, lead up to the public release of Firefox 4, expected to arrive in beta form later this month.

Updated June 10th, to clarify Firefox 4 launch this month is beta, not the public release.