[Libav-user] License Compliance Checklist

Axel Holzinger aholzinger at gmx.de
Sat Jun 27 22:17:16 CEST 2015

On Saturday, June 27, 2015, Robin Stevens wrote:

> On Saturday, June 27, 2015, Info || Non-Lethal Applications <info at non-
> lethal-applications.com> wrote:
> Hi,
> > if I read http://ffmpeg.org/legal.html there is #18 which says "Make sure
> > your program is not using any GPL libraries (notably libx264)."
> >
> > Could anybody please elaborate on this. How can a caller know if it opens a
> > file and tries to decode it, if Ffmpeg uses LGPL or GPL code?
> >
> > I know that Ffmpeg can be built without --enable-gpl resp. --enable-
> nonfree,
> > but what if the user replaces LGPLed shared Ffmpeg libraries with GPLed
> > shared Ffmpeg libraries? Now it could happen that an application - without
> > wanting to do so - is using GPL code inside Ffmpeg libraries and thus
> > infringing GPL.
> >
> > What can an application do (mean which Ffmpeg functions can be called) to
> > prevent this?
> I personally wouldn’t consider the improbable cause where a user exchanges
> a shared lib because this is - honestly - not my problem.
> If you are really concerned about this (but I really think you shouldn’t), you
> can put some special notice in your license agreement.
> I don’t know which platforms you’re targeting but on the Mac, I’d just put
> the libs inside my app bundle and make sure that they are loaded from
> there.
> Only my two cents ...
> The GPL only has effect if you distribute software licensed under it.
> If someone substitutes your lgpl libs with gpl versions, no distribution has
> taken place.
> If they were subsequently to redistribute (assuming they had that right in
> your software)... Hmmm, that's tricky but I'd suggest they can't do that.
> If you give them the right to distribute your software, you should limit it
> redistribution of an unmodified copy, which would avoid this (and other)
> problem(s).
> Cheers
> Rob

Thanks to both of you.

I didn't consider that (L)GPL is about distribution.


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