gstreamer decoders [LWN.net]

gstreamer decoders

Posted Feb 3, 2010 14:38 UTC (Wed) by mjw (subscriber, #16740)
In reply to: gstreamer decoders by DonDiego
Parent article: Blizzard: HTML5 video and H.264 - what history tells us and why we're standing with the web

> > Our reading of the GPL and LGPL, which are licenses governing the
> > distribution of software, you need to give the same rights to your
> > recipients as you have, and they need to be able to redistribute with
> > the same rights as well.

> False. You need to give recipients the same rights that you received when
> getting the software. You received FFmpeg as (L)GPL from us, you have to
> pass it along as (L)GPL again. The (L)GPL says nothing about a contract
> with the MPEG LA.

Actually the LGPL does if such contracts are about patent licenses (quotes from GPLv2.1, but other versions have similar obligations):

Finally, software patents pose a constant threat to the existence of any free program. We wish to make sure that a company cannot effectively restrict the users of a free program by obtaining a restrictive license from a patent holder. Therefore, we insist that any patent license obtained for a version of the library must be consistent with the full freedom of use specified in this license.
[...]
If you cannot distribute so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not distribute the Library at all. For example, if a patent license would not permit royalty-free redistribution of the Library by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Library.

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gstreamer decoders

Posted Feb 3, 2010 15:08 UTC (Wed) by paulj (subscriber, #341) [Link]

Don Diego is talking about the case where you distribute GPLed code where
you have *no* agreement with any patent licensors. This is perfectly
acceptable, at least wrt the licence.

It is a fallacy to say that every distributor of GPLed software must ensure they
have blanket downstream licences to all potentially applicable patents. The only
thing refusing to distribute protects against is legal risk to the *distributor*, and
a lesser risk to the recipient from the *patent holder* - not the licensor of the
GPL software!

See also my other reply, an uncle of sorts to this one.

(L)GPL vs. patents

Posted Feb 3, 2010 15:28 UTC (Wed) by DonDiego (guest, #24141) [Link] (10 responses)

> Actually the LGPL does if such contracts are about patent licenses
> (quotes from GPLv2.1, but other versions have similar obligations):

> Finally, software patents pose a constant threat [...]
> [.. continue quote from the preamble..]

This is from the preamble of the LGPL. As it has no effect on the license itself and is in no way legally binding, it is best ignored.

> If you cannot distribute so as to satisfy simultaneously your
> obligations under this License and any other pertinent obligations,
> then as a consequence you may not distribute the Library at all. For
> example, if a patent license would not permit royalty-free
> redistribution of the Library by all those who receive copies directly
> or indirectly through you, then the only way you could satisfy both it
> and this License would be to refrain entirely from distribution of the
> Library.

This just means that other contracts do not excuse you from the obligations of the LGPL. Any downstream recipient must continue to receive the full LGPL rights, the redistributor is not allowed to restrict them, no matter what other obligations say.

If somebody has a contract with the devil that claims a limb for each redistribution of FFmpeg then that person will quickly run out of limbs and then have a serious problem with the devil, but with nobody else.

Downstream recipients are not affected. They have no contract with the devil, they need not fear for their limbs, they just need to abide by the terms of the LGPL.

(L)GPL vs. patents

Posted Feb 3, 2010 15:48 UTC (Wed) by mjw (subscriber, #16740) [Link] (6 responses)

> This is from the preamble of the LGPL. As it has no effect on the license itself and is in no way legally binding, it is best ignored.

Of course it is not smart to ignore the text of the license. The preamble makes clear what the intent is of the legal clauses. In case their is any doubt how to interpret a particular clause one looks at the intent to see that "any patent license obtained for a version of the library must be consistent with the full freedom of use".

> > if a patent license would not permit royalty-free
> > redistribution of the Library by all those who receive copies directly
> > or indirectly through you, then the only way you could satisfy both it
> > and this License would be to refrain entirely from distribution of the
> > Library.
>
> This just means that other contracts do not excuse you from the obligations of the LGPL. [...] Downstream recipients are not affected.

Yes, but it does affect the (re)distributor. If they get a patent license, then they have to make sure that it covers not only themselves, but also all the recipients of any copies of the library. You might think that is the problem of those who take out such a patent license, and that they would be foolish to get into a contract with something like the MPEG LA. (And you might be right about that.) But it is still a real problem for such companies that do.

(L)GPL vs. patents

Posted Feb 3, 2010 16:02 UTC (Wed) by DonDiego (guest, #24141) [Link] (5 responses)

> > This is from the preamble of the LGPL. As it has no effect on the license itself and is in no way legally binding, it is best ignored.

>Of course it is not smart to ignore the text of the license. The preamble makes clear what the intent is of the legal clauses. In case their is any doubt how to interpret a particular clause one looks at the intent to see that "any patent license obtained for a version of the library must be consistent with the full freedom of use".

Sure? OK, let's try:

PREAMBLE

The book club is a non-profit, for-good, honest, no-nonsense organization that strives to bring its members peace, prosperity, happiness and easy access to their favorite books with absolutely no hooks attached

CONTRACT

666. (f) If you have read this far, we will now inform you that we will send you a few books per week at not exactly premium conditions. They will be a random choice of the old stuff we could not sell otherwise. You may not give them back and pay within three days.

Construct a slightly less contrived example if you wish, but still the fact remains: the preamble is not legally binding.

> > This just means that other contracts do not excuse you from the obligations of the LGPL. [...] Downstream recipients are not affected.

> Yes, but it does affect the (re)distributor. If they get a patent license, then they have to make sure that it covers not only themselves, but also all the recipients of any copies of the library.

No. BTW, the SFLC agrees with us.

(L)GPL vs. patents

Posted Feb 3, 2010 16:49 UTC (Wed) by rahulsundaram (subscriber, #21946) [Link] (4 responses)

Can you provide a reference to SFLC's interpretation? I haven't
seen it

(L)GPL vs. patents

Posted Feb 3, 2010 17:53 UTC (Wed) by DonDiego (guest, #24141) [Link] (3 responses)

I can see if I get something in writing, it's all from talks with one of our devs that also lives in New York so far.

Much more importantly, this is the official interpretation of FFmpeg. Since we are the copyright owners, our interpretation is the one that matters. We still need to put that in writing.

(L)GPL vs. patents

Posted Feb 4, 2010 16:00 UTC (Thu) by rahulsundaram (subscriber, #21946) [Link] (2 responses)

If you want your claims to be taken seriously it needs to be in writing If
you are repeatedly going to refer to claims about SFLC's interpretation it
would be beneficial to get it in writing as well

(L)GPL vs. patents

Posted Feb 4, 2010 16:07 UTC (Thu) by DonDiego (guest, #24141) [Link] (1 responses)

I am an FFmpeg copyright holder, so you already have a statement from me. We shall try to make something more official and put it on our website.

I would like you to provide me with the contrary interpretation in writing as well. You claim that the FSF has made statements to a different effect, but I never saw such a thing.

(L)GPL vs. patents

Posted Feb 4, 2010 16:27 UTC (Thu) by rahulsundaram (subscriber, #21946) [Link]

Collectively a group making a statement is quite different from a single
copyright holder and I made no claims about FSF's interpretations You are
confusing me with someone else

(L)GPL vs. patents

Posted Feb 3, 2010 15:59 UTC (Wed) by paulj (subscriber, #341) [Link] (2 responses)

Are you saying that a patent licensor can continue to distribute a GPLed work
implementing that patent even when the licence is not passed on? That
doesn't seem to in concordance with the GPL.. Though I can't tell if you're
claiming that, or if you're just talking about the rights of the downstreams.

Where you seemed to be saying that non-licensees were unaffected (other
than risk from patent holder) and able to distribute just fine, I agree with you.

(L)GPL vs. patents

Posted Feb 3, 2010 15:59 UTC (Wed) by paulj (subscriber, #341) [Link] (1 responses)

a patent licen/see/. Grr.

(L)GPL vs. patents

Posted Feb 3, 2010 17:58 UTC (Wed) by DonDiego (guest, #24141) [Link]

That's exactly what I'm saying. A patent licensee can continue distributing FFmpeg under the LGPL no matter what other side deals are in effect.