[FFmpeg-user] Can I use FFmpeg.exe command line in my proprietary software

Nicolas George nicolas.george at normalesup.org
Sun Aug 7 23:32:33 CEST 2011

[ I know answering to this person is usually wasted time, but his message
can fool earnest readers. ]

Le decadi 20 thermidor, an CCXIX, Phil Rhodes a écrit :
> >as long as you only call a binary application via
> >cli it does not matter under what license the called
> >cli-app is because you do not touch it, no matter if
> >it is GPL, LGPL, Commerical.....
> This would be one of the reasons why the GPL and its derivatives
> make absolutely no sense whatsoever.
> What's the functional difference?!

There is a reason, and it is a legal one.

The legal basis that allows the viral clause of the GPL to work is that
under copyright law, one can not distribute a works without the consent of
its author, and the author can pose almost any condition to give his

When building a program using a library, even a dynamically linked one, part
of the library is embedded in the final binary: the library's copyright
owner can pose his condition on the distribution of said binary.

On the other hand, a program that calls ffmpeg as an external program, no
part of ffmpeg is embedded. The program can even be built on a system where
ffmpeg is not installed and never was. Therefore, ffmpeg's copyright owners
can not pose any condition.

Unfortunately, a variation on this argument could allow anyone to distribute
a proprietary program linked to GPL ffmpeg libraries; but I will not explain
my reasoning publicly here, as I consider it a violation of the spirit of
the license and do not want to encourage it.


  Nicolas George
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