HTML5 video has a few hurdles to leap before it can fully replace Flash, but one looms larger than all others: Opposition to proprietary video formats, like h.264. Conveniently, Google has just open-sourced their own format, called WebM.
If you've been following the Flash/HTML5/h.264 drama for the last few months, this news might sound a little familiar: That's because in August of last year, Google acquired a firm called On2, a video compression company with handful of video codecs—the VP series, including the latest, VP8. Many people suspected that Google, which owns YouTube, would roll support for these codecs into its products—including Chrome browser—and possibly even open-source VP8.
And, well, that's what they've done: They've effectively open-sourced VP8, under the name WebM. The entire WebM project includes a video codec (VP8, basically), and audio codec (Ogg Vorbis) and a container, based on .mkv, or Matroska. It'll support HD, obviously. Most importantly, it's not bound by royalties or restrictive licenses.
What this means is that anyone building a web video site, or a browser, now has a new alternative to h.264, the preferred proprietary standard, and Ogg, an open source standard that pretty much nobody uses.
Does this matter to you? Yes! How? Well..
As it stands, HTML5 video is in a deadlock: Browser makers like Mozilla (Firefox) and Opera want web video to be based on open technology, like Ogg, because it avoids messy royalty and licensing schemes, and in the case of Firefox, can be integrated into the browser, which itself is open source. Apple, Google and Microsoft (along with most web video providers who're using HTML5, are going ahead with the h.264 standard, which offers tight compression, and wide access to hardware acceleration (many devices can use video hardware to decode h.264 video already).
As the Ogg folks see it, h.264 isn't free enough—its future could become mired in copyright and licensing battles, which wouldn't be good for anyway. And for the Mozilla foundation in particular, the concept of proprietary formats is philosophically unacceptable. As the h.264 folks see it, Ogg is an inferior standard, and is itself subject to legal threats, from which it wouldn't really be defended. (Who would step up?) Hence, stalemate.
Google's WebM offers the best of both worlds, in theory: It's a well-compressed, advanced standard, now free in all senses of the word, and backed by a massive corporation that could presumably a.) oversee its spread and use and b.) protect it in court, should anyone have any problem with it.
Mozilla and Opera are already on board to support the standard in upcoming browser releases, as is Adobe; all promising, but all predictable. We won't really know if WebM will matter, though, until support shows up in other browsers: Chrome is a given, but what about Safari and IE? Lack of support from Microsoft would leave WebM dead in the water, and Google—and others—unable to deploy it in earnest. That, and current gen hardware won't accelerate WebM decoding, so it's really not practical on mobile devices, which depend on hardware support to make streaming video smooth, and prevent battery suck. (This means no support in current-gen iThings and smarpthones.)
For now, though, Google's collected a few toys for us to play with, including supported browsers and a special YouTube test trick, so you can see what it looks like. (Spoiler: It looks like YouTube.)
Update: Oh man, here's some promising news from Mary Jo Foley: According to her sources, Microsoft will support WebM in IE9.
Update II: Microsoft confirms, which bodes very well for WebM, albeit years down the line. (IE9 isn't due out until 2011.) That leaves the ball in Apple's court, which, well, should be interesting to watch.
Update III: Aaaand we have the first dissent: h.264 developer Jason Garrett-Glaser calls the spec "and H.264 Baseline Profile with a better entropy coder." In English, this means he believes the spec to be too close to h.264 in some ways, which could leave it open to attack by MPEGLA, the company that licenses h.264. He also calls the spec sloppy and incomplete—perhaps predictable given his background, but interesting nonetheless. Lesson: Nothing is simple in web video.