Microsoft has put its stake in the ground and committed to supporting H.264 in Internet Explorer 9. That the next browser version would support H.264 HTML5 video was no surprise (though the current Platform Preview doesn't include it, it was shown off at MIX10), but this is the first time that Microsoft has provided a rationale for its decision. More significantly, this is the first time the company has confirmed that H.264 will be the only video codec supported.
H.264 certainly has some advantages. It's standardized, resulting in wide support in both software and hardware. This also provies a migration path of sorts from Adobe Flash; the same H.264 video file can be played both in Flash and via the native browser support, which allows site owners to target both HTML5 and Flash users with a single codec. But the biggest advantage cited by Microsoft was intellectual property: the IP behind H.264 can be licensed through a program managed by MPEG LA. Other codecs—the blog post named no names, but Theora is obviously the most widespread alternative for HTML5 video—may have source availability, but they can't offer the same clear IP rights situation.
The codec choice is a long-standing issue with HTML5. The current draft specification refrains from mandating any specific codec, and the result is a schism. Firefox and Opera have gotten behind Theora, citing its openness; Safari and now Internet Explorer 9 have gone for H.264. Chrome supports both. It's not impossible that the spec will ultimately be changed to specify a specific codec—and that codec might not be H.264. If that turns out to be the case, Redmond will likely have to revisit the decision.
H.264 has its problems, though. It's currently royalty-free for Web usage, but there are no guarantees that this will continue in the future. In contrast, Theora is perpetually royalty-free.
The status of Theora might change if patent concerns emerge—though designed to avoid patented technology, there are no assurances in the murky world of software patents—and so there is some risk to browser vendors. But the unfortunate reality is that's true of H.264 too. MPEG LA may believe it holds all necessary IP rights to H.264, but one never knows when a patent troll might emerge unexpectedly from the deep. H.264 might be the safer option, but the difference is not as clear as Microsoft makes out.
The decision may also be premature if Google opens up VP8, as is widely expected. If Google does indeed publish the source, and offers perpetual royalty-free usage of the VP8 patents, the codec may offer the same level of freedom and openness as Theora, combined with the corporate backing of Google, and assurances that both Google (and On2 before it) have done their due diligence.
Google would also have the power to promote VP8 in other ways; as owner of YouTube, the company could, in principle, make VP8 one of the most widely used codecs on the Internet. Adoption by the company's own Chrome browser is all but certain, and if the terms are suitable, VP8 could also find its way into Firefox and Opera. Such a move would give VP8 considerable momentum.
Microsoft's decision to support only one codec is also a little surprising when one considers the way in which video support will be implemented. Internet Explorer 9 will use the Media Foundation media decoding framework that's part of Windows Vista and Windows 7—another reason that the browser won't run on Windows XP. Just as with its predecessor, DirectShow, Media Foundation is an extensible framework that allows third-party codecs to plug in to the media infrastructure so that applications can use them automatically.
If Redmond allowed IE9 to use Media Foundation without any restrictions, it would enable the browser to use whatever codecs were installed; H.264 is already included with Windows 7, so it might be a good default, but there's nothing preventing Google from producing a VP8 plugin for Media Foundation, for example. This would provide automatic support to IE9 users for VP8 video.
That said, with the browser locked down in its protected mode sandbox, and the fact that Media Foundation codecs should all be modern (and hence, security-conscious), the risk seems marginal. Morever, there are likely other ways to feed malicious video into insecure codecs (embedding Media Player, for example), so the level of protection this offers isn't clear.
HTML5 video is an important part of Internet Explorer 9, and given the big-name industry support for H.264, Microsoft's decision was not altogether surprising. As welcome as the new capabilities are, the decision to rule out the more open codecs is somewhat disappointing.
Source: ars technica