[Theora] Independent implementations?

[Kyungjoon Lee]

Hullo,

When people ask me what Vorbis's license terms are, I usually tell
them that the bitstream format is in the public domain, that the
reference libraries are licensed under a BSD-like license, and that
the example programs are licensed under the GNU GPL. (Note the
distinction between filespec and implementation here.)

Meanwhile, Theora.org's FAQ doesn't say anything about the state of
the filespec, besides this:

> Yes, some portions of the VP3 codec are covered by patents. However, the
> Xiph.org Foundation has negotiated an irrevocable free license to the VP3
> codec for any purpose imaginable on behalf of the public.

So my question is, is it alright to create and distribute a Theora
codec which isn't based on the Theora code from Xiph.org? If VP3 code
is in Theora, and VP3 is patented, does that mean that you can't
write/modify a non-Xiph Theora codec without infringing on On2's
patents?

Thanks in advance,
Kyungjoon Lee