[theora] Some questions about Theora IP
mjs at apple.com
Sat Jul 4 07:09:24 PDT 2009
Hello Theora developers,
I'm doing some cursory research into Theora's IP status in preparation
for asking Apple to reconsider the possibility of shipping an
implementation. I have a few questions and I'm hoping knowledgeable
people can help out.
1) What are the terms of any patent licenses or disclaimers, and do
they have field of use restrictions or limitations on code for which
the patents are licensed?
I found the following patent license in the original VP3.2 source: <http://svn.xiph.org/branches/vp32/vp32/VP32_license.txt
>. This appears to have a sort of field-of-use restriction on the
patent license terms; products that don't support the original VP3
bitstream do not get the patent grant. The patent license is also
limited to the VP3.2 code itself and derivative works thereof.
I also found this promise of patent non-assertion: <https://svn.xiph.org/trunk/theora/LICENSE
>. This doesn't have a field-of-use restriction, but it does appear
to limit the promise not to assert to the original VP3 code and
modifications to that code.
While looking for info, I found this thread from 2004 asking if On2's
patents on Theora were licensed for independent implementations: <http://lists.xiph.org/pipermail/theora/2004-July/000544.html
>. There didn't seem to be a clear conclusion at the time.
Does anyone have further info on this? Are there additional agreements
between On2 and Xiph besides the above documents?
Note: I expect that in practice, On2 isn't looking to stop independent
implementations, and perhaps didn't intend the limitation on the
patent disclaimer at all. However, companies have been known to
suddenly become more litigious (for example if they get axquired), and
in such a case I would expect a literal reading of the patent license
and the promise not to assert. It also seems important for the patent
status to be really clear for purposes of the W3C Patent Policy, if
Theora were to be required by HTML5 or other specifications. I'm not
sure a royalty-free patent license that doesn't cover independent
implementations would be good enough. Perhaps whoever did the
negotiating with On2 could get them to publish a clearer statement.
2) Is there any public information about what patents On2 holds that
may read on Theora? (This information isn't essential but I couldn't
find it stated anywhere.)
3) Has anyone done any research to determine if there might be patents
that read on Theora held by parties other than On2? I know this is a
sensitive topic, and anyone who has that kind of info might not be
able to share it. But if anyone has done even partial research, that
would be very useful. I'm wondering for example if anyone has done
some of the more obvious obvious checks, like studying the patents
that are known to apply to MPEG-2 Video, MPEG-4 Part 2, or H.264/AVC,
since Theora has a roughly similar basic design.
4) Has On2 ever said anything about whether parties besides them hold
patents on VP3?
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