Re: [rtcweb] Proposal for H.263 baseline codec

"David Benham (dbenham)" <> Thu, 26 April 2012 00:32 UTC

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Date: Wed, 25 Apr 2012 17:32:15 -0700
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Thread-Topic: [rtcweb] Proposal for H.263 baseline codec
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From: "David Benham (dbenham)" <>
To: Gregory Maxwell <>,,
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Subject: Re: [rtcweb] Proposal for H.263 baseline codec
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Great summary & clarification, Gregory.

When one receives/signs the MPEG-LA license for H264 pool, all of the
patents (~8 pages worth) are listed so that the licensee knows what they
are covered for.   

Wasn't able to find a list of patents currently licensable/owned by
Google that are included in the royalty free VP8 bitstream spec or
implementation license.  With that info, presumably one's experts could
make a risk assessment (yes, easier said than done) as to what might
exist but *not* be covered by the VP8 license.   Has Google published
the list of patents minimally covered by your VP8 licenses?
Independently searching  through ON2 patents awarded/filed might perhaps
come close, but a definitive list from Google would be much more

> -----Original Message-----
> From: Gregory Maxwell []
> Sent: Friday, April 20, 2012 2:19 PM
> To: EXT -;
> Subject: Re: [rtcweb] Proposal for H.263 baseline codec
> wrote:
> >On 03/29/2012 09:53 AM, Stephan Wenger wrote:
> >> The other issue, though (the fact that the license grant extends
only to
> >> the VP8 implementation as provided by google, and does not extent
> >> derivative works such as hardware implementations) should be
> moderately
> > This is concerning, even for us open source software distributors.
> > fact, a similar situation existed some time ago with iLBC; the
> > that GIPS offered covered only the code as distributed as part of
> > RFC (although the language stating this was quite poorly
> Stop. All of you are confused.
> Maybe I can help-
> There are _two_  VP8 patent license grants:
> One for the specification:
> One for the software:
> These grants are subtly different in the scope of what they cover.
> There are important licensing drafting reasons for a construction
> which distinguishes "an implementation" and "any implementation".
> In particular, the license drafter writing this kind of a royalty free
> license has a tricky time making sure that the permission is broad
> enough to include all the correct coverage,  but not so over-broad
> a malicious implementer could (e.g.) add a search engine to their VP8
> encoder and claim that the VP8 license entitles them to search
> So, the drafter says something like- "those patent claims [...] that
> are necessarily infringed by implementation of this specification",
> which achieves the desired limited scope- and that is _all_ you get
> with the MPEG-LA pool patent licenses. This is what the Google
> spec license provides.
> But, if we're to be serious and honest about making a royalty free
> and implementation that permission isn't quite sufficient: The
> implementation might practice some VP8 related techniques which are
> "necessarily infringed"- they're helpful performance enhancements,
> they could simply be one option out of many ways of doing the same
> or could just be something that was incidentally included (or even a
> malicious patent trap snake in the grass)- and so it's important that
> everything in the reference software also be licensed- even if its not
> "necessarily infringed" by the specification.   But since it's not a
> goal to also license unrelated things that a downstream user may cram
> (e.g. a search engine), that license must be limited in scope to
> which are actually in the reference implementation: "This grant does
> include claims that would be infringed only as a consequence of
> modification of this implementation." (this language is actually
> identical to the language for this purpose in the GPL, FWIW)
> So, in summary:
> You are licensed, via the bitstream license, for anything Google
> which is necessary to implement the specification- in hardware,
> software, home grown, or reference implementations.  This is pretty
> much as strong a grant as you can find anyone offering for any other
> format specification.
> You are also licensed, via the additional rights license, for any
> use of the VP8 reference implementation including modified versions,
> limited to the extent that the modifications don't expand the scope of
> the coverage. (Exactly as the GPL explicit patent grant does)
> This has already been clarified by Google on this list:
> "Google confirms that the VP8 patent grant applies to both
> third-party hardware and software implementations of VP8."
> I admit that the fact that there are two similar but distinct licenses
> is a little confusing, but I don't understand why we have to go over
> it again and again on this list.  I would think that the prior Google
> comment would have been sufficiently definitive.