[XviD-devel] GPL and Windows

James Briant alien at species.org
Mon May 5 15:54:25 CEST 2003


I refer you to the GPL FAQ (http://www.fsf.org/licenses/gpl-faq.html):

"Can I use the GPL for a plug-in for a non-free program?

If the program uses fork and exec to invoke plug-ins, then the plug-ins are
separate programs, so the license for the main program makes no requirements
for them. So you can use the GPL for a plug-in, and there are no special
requirements.

If the program dynamically links plug-ins, and they make function calls to
each other and share data structures, we believe they form a single program,
so plug-ins must be treated as extensions to the main program. This means
that linking the GPL-covered plug-in with the main program would violate the
GPL. However, you can resolve that legal problem by adding an exception to
your program's license which gives permission to link it with the non-free
main program."

So its quite clear that its not just distribution but also *linking* that is
prohibited. For example, you cant avoid the license simply by writing an
installer that directs the user to ftp.redhat.com, downloads redhat, and
then links.

Another part of the FAQ states:

"I am writing free software that uses non-free libraries. What legal issues
come up if I use the GPL?

If the libraries that you link with falls within the following exception in
the GPL:

     However, as a special exception, the source code distributed need not
     include anything that is normally distributed (in either source or
     binary form) with the major components (compiler, kernel, and so on) of
     the operating system on which the executable runs, unless that
     component itself accompanies the executable.

then you don't have to do anything special to use them. In other words, if
the libraries you need come with major parts of a proprietary operating
system, the GPL says people can link your program with them."

So the question becomes, is the Windows Media Player one of the "major parts
of a proprietary operating system". Unfortunately, the FSF has argued to the
US supreme court and to congress, that neither Internet Explorer, nor the
Windows Media Player, form a major part of the operating system, and are
merely applications distributed by Microsoft with the OS, while Microsoft
has argued that they are core products. So are guys siding with Microsoft,
or with FSF, RMS, and the US Supreme court? :)

This leaves, as a final recourse:

"If you want your program to link against a library not covered by that
exception, you need to add your own exception, wholly outside of the GPL.
This copyright notice and license notice give permission to link with the
program FOO:


   Copyright (C) yyyy  <name of copyright holder>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
USA

    In addition, as a special exception, <name of copyright
    holder> gives permission to link the code of this program with
    the FOO library (or with modified versions of FOO that use the
    same license as FOO), and distribute linked combinations including
    the two.  You must obey the GNU General Public License in all
    respects for all of the code used other than FOO.  If you modify
    this file, you may extend this exception to your version of the
    file, but you are not obligated to do so.  If you do not wish to
    do so, delete this exception statement from your version."

So, the authors can extend the license for XVid by either listing the third
party applications that they allow the codec to be used with, by explicitly
listing those that are approved, e.g. windows media player, adobe premiere,
etc. If they offer a general extension to *any* application that uses
windows codec pluging, then *anything* can link with, and theres no point
using the gpl at all.

The question must be raised, "why support a windows media codec at all?". If
the goal it to have  xvid be used by other gpl'd applications, then it need
only be released as a lib. This guarantees that only GPL'd applications can
use it, since they must be explicitly linked. However, by supplying the
codec as a windows media codec, the authors are deliberately providing the
codec in a format which exists only to make the codec available to *any*
application dynamically at run time. One could argue that this deliberate
use is explicit permission. You'll probably find that it violates various
Microsoft licenses too.

The goal of free software is not to make Windows more useful. Certainly the
FSF did create the LGPL in order to make free software more widely used, but
only in so far as having the non-free world make the free-world easier to
use. It wasnt set up so that the free-world could make non-free applications
like WMP and Premiere easier to use. If you believe in the GPL, then release
the software GPL, i.e. for linux, and for other GPL'd applications. Dont
make non-free windows easier to use, and it dont release it in a format
whose only purpose is to be used by any application, free and non-free
alike.

On the other hand, if you arent FSF zealots, and you think that the windows
world could do with a free mpeg4 codec, then by all means release it, but
you cant do it using GPL. LGPL, yes. FreeBSD, yes. But not GPL.

Jamie



-----Original Message-----
From: Christoph Lampert [mailto:chl at math.uni-bonn.de]
Sent: 05 May 2003 13:19
To: alien at species.org; xvid-devel at xvid.org
Subject: Re: [XviD-devel] GPL and Windows



Hi,

You misunderstood GPL.

GPL does not restrict _usage_ in any way. You are allowed to
_use_ XVID with Windows, with any proprietary software like Media
Player for decoding, or Adobe Premiere for encoding.

What GPL forbids is the _distribution_ of derived works based on XVID,
where "derived works" usually is interpreted in a very broad sense.
So, Microsoft is not be allowed to bundle Windows and XVID into
a "Multimedia-Windows" or something. Adobe is not allowed to create a
version of Premiere which already includes XVID, that would be
_distribution_ of derived works.

gruel


On Mon, 5 May 2003, James Briant wrote:
> Guys,
>
> Whats the plot with a GPL license and windows media player codec? I'm sure
> you've been asked this before, but in case you havent:
>
> Windows codecs are loaded as dynamic linked libraries into windows
> applications such as windows media player, or third party applications.
> Consequently it is a violation of the GPL to release your software as .dll
> and advocate its use as a windows codec. Frankly it wouldnt even be
> acceptable to release it as an .exe that ran in a seperate process. The
> codec is clearly something which cannot serve its purpose by itself and
any
> linking with it, even if you added a network wrapper and used it via
> siberia, you would violate the GPL if any part of the system wasnt GPL'd
> too.
>
> If you wish to release your software for windows users (as a windows media
> codec), you need to use the LPGL, not the GPL. As it is, anyone can write
a
> non-GPL application on windows and use your GPL'd codec because it would
be
> the *user* not the *author* who selects your codec.
>
> Further, from the legal point of view (IANAL BTW) since you own the
> copyright on Xvid, you have the right to offer your software under any
> license you wish. One could argue, therefor, that since you have
explicitly
> developed your software for, and advocated its use with, windows media
> player, that you are extending the licensing terms to include non-gpl'd
> software such as wmp.
>
> Can you clarify your intentions?
>
> jamie
>
>
> _______________________________________________
> XviD-devel mailing list
> XviD-devel at xvid.org
> http://list.xvid.org/mailman/listinfo/xvid-devel
>




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