If you are not restricted by the patent (e.g. never signed a deal with the
licensor, not subject court injunction), then you can
distribute just fine without compromising the free software licence on the
code. This is true regardless of whether or not the code is subject to patents,
for you are in the same position as the recipient, which is all the GPL licence
If you choose not to distribute a codec because you know it is patented, then
you do so because you are protecting *yourself* from legal risk - not because
the licence requires it. It is a misunderstanding to claim the licence is the
barrier, as you could happily distribute away and not violate any free software
licences, given the above.
I think the above may be what Don Diego is trying to communicate, and it fits
in with my understanding of the GPL and patent issues (IANAL, etc).
If you come to an agreement with the patent holder, then obviously you
must secure a blanket agreement that covers all your down stream users. If
the patent only applies in certain countries, then note that the GPL allows
code to be distributed with geographic exceptions set by the rights holder,
while (it seems, but am not certain) remaining GPL compatible.
The next question, which I think you or others in the Mozilla camp (and
perhaps the FSF?) have tried to raise is the question of whether patent
encumbered technologies should be resisted by promoting other, less
encumbered technologies. This is an interesting one, but it is implied per se
by licensing obstacles to distribution on the code.