The 'but' here comes from the HTML 5 part, which includes a
<video>tag that essentially renders Flash video obsolete, with decode and render available natively in the browser, rather than through a plugin. The standards committee overseeing HTML 5 still hasn't agreed on what format that video should be delivered in. The de-facto standard of h264, a high-quality, industry-driven standard that's nevertheless mired in patent and licensing issues that are really sticky. Or Xiph's Theora, which has been designed to avoid using techniques covered by patents, and is available royalty-free (which most of us think of when we think 'free').
When it comes to browser support, the big three unsurprisingly lend their weight to h264. Mozilla's Firefox—distinct from the others in being the only organisation that's an actual browser company and also non-profit—throws its weight behind Theora, with that crazy idea that participating in the web shouldn't involve licensing fees just to access it.
Of the corporations, Google has interestingly promised to open source the VP8 codec and, since they own YouTube, could theoretically swing the balance by offering VP8 support in Chrome and VP8 YouTube videos, especially if Firefox supported the same.
But, back to Apple.
Steve Jobs reckons that there's no such thing as a free video codec. Furthermore, he issues a threat to Xiph over Theora (without including useful specifics, which relegates it to FUD).
So Steve: get a grip. The i-whatever ecosystem is locked down tight, and you're free to do that to whatever extent your customers are willing to put up with, but don't hide behind a wall of righteousness when dissing other technologies. Your 'open' arguments are empty with a platform and environment that is increasingly developer hostile.
As for me, I've owned a G4 PowerBook and am typing this on a two year old Macbook Pro. With each statement from Jobs regarding criticism of his closed platform, I find it increasingly unlikely that I'll buy a third. So hey, Apple marketing-types: your CEO's statements are costing you a £1500 sale, and most likely not just from me.
Apparently Apple once believed in a royalty-free Web, too. However, despite the original having lived here on apple.com for years, it's recently been pulled.
Thankfully, George Orwell's Memory Holes are a difficult thing to accomplish with an open Web.
Hat-tip to ZeroGravitas on Hacker News for the info (and to Create on the comments page for the Memory Hole reference).