[Theora] Independent implementations?

Maik Merten maikmerten
Wed Jul 14 14:33:59 PDT 2004

<Pine.LNX.4.58.0407142253200.27310 at login.math.uni-bonn.de>
Message-ID: <40F5A6C7.6030605 at gmx.net>

Christoph Lampert wrote:
>>However, On2?s patents surely _do_ apply.
> Hm, do they? I still haven't seem what they patents actually are about.
> Do they cover parts of the binary format? Or a way of encoding? Or
> decoding? Just because yours video message is binary compatible to Theora
> doesn't make contain patented routines from other systems binary
> compatible to theora. You would have to check item by item what really is
> patented and how.

I assumed that they patented VP3-technology in way you can?t workaround
if you want a compatible bitstream. This may or may not be the case.

>>How could a passage in a license that doesn?t apply to my software
>>protect me?
> It could indicate that On2 gave a free irrevocable license to everyone to
> use the routines which they have a patent on _for every purpose you wish_.
> But they didn't, they just gave permission to use those routines for VP3
> and derived works of that. This is much less, because now you will have
> two choices. Either you declare your software to be independent. Then you
> don't have permission to the patents, or you declare it derived works,
> then you have to obey the license that VP3 came with!

There are two differently licensed flavors of VP3:
- the original tarball from on2 (VP3-license)
- the code in Xiph SVN (Xiph BSD-like license + irrevocable license on

"6.2. Effect of New Versions.
Once Covered Code has been published under a particular version of the
License, You may always continue to use it under the terms of that
version. You may also choose to use such Covered Code under the terms of
any subsequent version of the License published by On2. No one other
than On2 has the right to modify the terms applicable to Covered Code
created under this License."

So you can choose.

Most people with programming skills don?t live in caves. It?s highly
likely that any implementation compatible with Ogg Theora is written
with the help of the Ogg Theora specification (which _is_ derived from
VP3-code). Is any code written with the help of this specification
automatically derived from the VP3-codebase (which surely is covered by
the irrevocable patent license)? Then there would be no problem....

> But their patents could apply to many more situations than video encoding
> in VP3-like fashion. By giving a free license for _every_ purpose, they
> might just as well give up the patent claim itself, then all the
> difficult software license stuff wouldn't be necessary anymore.

Good point.

> chl
> P.S. Btw. did anyone try to simply _ask_ them what the status is?

I don?t know :)
However, it?s obviously a good idea.

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