[MPlayer-users] Re: License

Robinson, Chad crobinson at rfgonline.com
Tue Oct 9 15:31:07 CEST 2001

> Yes, Mplayer actually violates the GPL. Because you can't distribute
> anything which is derivative of some GPLed work with different license
> GPL. The license of the included things would have to be at least LGPL and
> then you would have to include these included things by dynamic linking at
> runtime (no static linking). Other way you aren't allowed to distribute
> program.
> So GPLed program isn't possible to link with proprietary codecs DLLs.

I don't think this is completely true, but there is a serious gray area
right now. MPlayer itself is "basicly GPL" according to
http://www.mplayerhq.hu/homepage/info.html, but that's the only place I can
find a reference to MPlayer's license! To be properly protected by the GPL,
the source code must include a copy of the license - somebody needs to
include the file "COPYING" that you can find with so many other packages in
the MPlayer source. It's also wise to refer to the GPL in the command line
usage screen, and to place at least a one-line "Copyright (c) YEAR,
PersonWhoWroteIt" comment at the top of each source code file. (Making it
two lines, with the second line referring readers to the COPYING file, is a
good idea.) So the biggest issue is that MPlayer isn't even properly
PROTECTED by the GPL at this time.

The GPL doesn't cover activities OF a GPL program, only of other programs
against the GPL program. I've never seen a GPL Windows codec DLL - the DLLs
that are included with MPlayer don't violate the GPL, nor do any other
libraries. They may violate OTHER licenses held by Microsoft and so forth
(and probably do, until somebody gets around to rewriting them which is a
PITA), but they don't violate the GPL itself.

The question involves modification. If modification of a GPL program takes
place, due credit and reference to the original license must take place, and
source must be provided. (Actually, notice is due no matter what.) So, the

Which modules that would be included in binary form in MPlayer are covered
by the GPL? I don't see ANY license files on the libraries like libavcodec.
I would assume they were covered by SOME license...? If so, removing the
reference to the license violates the GPL.

More importantly, were any of these libraries modified in any way? If so,
binary distribution will be a problem. Otherwise, you can simply dynamically
link to them and stop wasting your time worrying about licenses.


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