Subject: Re: Google's patent license for VP8 [was: Google WebM?]
From: Ben Tilly <btilly@gmail.com>
Date: Thu, 20 May 2010 17:42:04 -0700

 Thu, 20 May 2010 17:42:04 -0700
On Thu, May 20, 2010 at 5:04 PM, Chris Travers <chris@metatrontech.com> wrote:
> On Thu, May 20, 2010 at 2:50 PM, Ben Tilly <btilly@gmail.com> wrote:
>
>>
>> I fail to see any drafting ambiguity at all here.  The patent license
>> that Google is giving is good for all patent claims in all patents it
>> owns, or will acquire, that this implementation could infringe on.
>
> What is the difference between "that this implementation could
> infringe on" and "necessarily infringed by this implementation?"

Good point.  I was sloppy with my wording because when I think about
it the difference is quite big.

Suppose, for instance, I used this license for an implementation of a
interpreted programming language.  The set of patents "that this
implementation could infringe on" include virtually all software
patents.  The set of patents "necessarily infringed by this
implementation" include everything that is part of how the interpreter
is written and is intended to be run.

> It seems to me that the latter is substantially narrower than the former.

It is.  In what seems to me to be an entirely appropriate way.