It seems to be widely accepted that WebM is a minor variation on H.264 with changes specifically designed to avoid the H.264 patents, which as you mention have been openly published and well documented for years.
Since large segments of H.264 were simply dropped for WebM, apparently there's only about 49 H.264 patents total (out of over a thousand) that could even remotely apply. That seems a reasonable number for On2 to work around, and for Google (and everyone else listed on their supporters page)'s lawyers to double check.
So now we are speculating about a random patent troll who happens to hold a patent that doesn't read on H.264 but does read on a simplified version of H.264 with some minor patent avoiding variations. Seems to me that if you're arguing H.264 is clean, then so is WebM.
Your interpretation doesn't match those of people who have analyzed it. The problem with WebM is that it may infringe on H264 patents! And its not clear they have done enough to avoid the problems. H264 has come together to form a very strong patent pool. None of the patents can be asserted against H264 (nor can the partner companies in general), but any of them can be asserted against WebM.
"But as noted in my previous post, merely being published by Google doesn’t guarantee that it is. Microsoft did similar a few years ago with the release of VC-1, which was claimed to be patent-free but within mere months after release, a whole bunch of companies claimed patents on it and soon enough a patent pool was formed."
"VP8 is simply way too similar to H.264: a pithy, if slightly inaccurate, description of VP8 would be "H.264 Baseline Profile with a better entropy coder". Even VC-1 differed more from H.264 than VP8 does, and even VC-1 didn’t manage to escape the clutches of software patents."
"Most importantly, Google has not released any justifications for why the various parts of VP8 do not violate patents, as Sun did with their OMS standard: such information would certainly cut down on speculation and make it more clear what their position actually is."
And not about patents, but the quality of the spec:
"The spec consists largely of C code copy-pasted from the VP8 source code up to and including TODOs, optimizations, and even C-specific hacks, such as workarounds for the undefined behavior of signed right shift on negative numbers. In many places it is simply outright opaque. Copy-pasted C code is not a spec. I may have complained about the H.264 spec being overly verbose, but at least it’s precise. The VP8 spec, by comparison, is imprecise, unclear, and overly short, leaving many portions of the format very vaguely explained. Some parts even explicitly refuse to fully explain a particular feature, pointing to highly-optimized, nigh-impossible-to-understand reference code for an explanation. There’s no way in hell anyone could write a decoder solely with this spec alone."
But maybe Google will fix it? Ummm think again;
"Update: it seems that Google is not open to changing the spec: it is apparently "final", complete with all its flaws."
I just don't see how one can feel equally comfortable with WebM.
"Dark Shikari makes several considerations, some related to the implementation itself, and many related to its “patent status”. For example: “VP8’s intra prediction is basically ripped off wholesale from H.264″, without mentioning that the intra prediction mode is actually pre-dating H264; actually, it was part of Nokia MVC proposal and H263++ extensions published in 2000, and the specific WebM implementation is different from the one mentioned in the “essential patents” of H264 as specified by the MPEG-LA.
If you go through the post, you will find lots of curious mentions of “sub-optimal” choices:
[big list of the identical features with minor differences between H.264 and VP8]
What we can obtain from this (very thorough – thanks, Jason!) analysis is the fact that from my point of view it is clear that On2 was actually aware of patents, and tried very hard to avoid them. It is also clear that this is in no way an assurance that there are no situation of patent infringements, only that it seems that due diligence was performed. Also, WebM is not comparable to H264 in terms of technical sophistication (it is more in line with MPEG4/VC1) but this is clearly done to avoid recent patents; some of the patents on older specification are already expired (for example, all France Telecom patents on H264 are expired)."
There's also a follow up here which discusses the thought process behind the 49 potential H.264 patents:
That's not an analysis, but a commentary on the work Jason did.
But he says a lot of BS, like, "In fact, one of the most brain damaged things of the current software patent situation is the fact that if a company performs a patent search and finds a potential infringing patent it may incur in additional damages for willful infringement (called “treble damages”). So, the actual approach is to perform the same analysis, try to work around any potential infringing patent, and for those close enough cases that cannot be avoided try to steer away as much as possible. So, calling Google out for releasing the study on possible patent infringement is something that has no sense at all: they will never release it to the public."
Patent law makes it VERY clear that treble damages occur with WILLFUL infringement. Good faith efforts, the inevitably fail, won't be subject to treble damages.
It seems like he's bending over backwards to show that Google shouldn't disclose anything, which is absurd.
His opinion that the suboptimal choices means that WebM has avoided the H264 patents seems very suspect to me. And contradictory, because if they did do what he said, and did accidentally infringe, by his (incorrect) logic they'd be liable for treble damages. Blech.
Mozilla's on the record as being told by their counsel not to openly publish patent research they did for Theora. They weren't happy about it, because it opens them up to FUD, but we all know patent law is messed up, one more absurdity shouldn't surprise us.
Since large segments of H.264 were simply dropped for WebM, apparently there's only about 49 H.264 patents total (out of over a thousand) that could even remotely apply. That seems a reasonable number for On2 to work around, and for Google (and everyone else listed on their supporters page)'s lawyers to double check.
So now we are speculating about a random patent troll who happens to hold a patent that doesn't read on H.264 but does read on a simplified version of H.264 with some minor patent avoiding variations. Seems to me that if you're arguing H.264 is clean, then so is WebM.