[FFmpeg-devel] [PATCH] G722 decoder

Diego Biurrun diego
Fri Mar 27 10:58:22 CET 2009

On Thu, Mar 26, 2009 at 06:53:20PM -0700, Baptiste Coudurier wrote:
> Diego Biurrun wrote:
> > On Thu, Mar 26, 2009 at 04:39:15PM -0700, Baptiste Coudurier wrote:
> >> Well, about 2) I already expressed concerns about 2 files in the 
> >> FFmpeg codebase namely vc1dsp_mmx.c and fdctref.c, which are not 
> >> _explictely_ part of FFmpeg, since it is not mentioned in their 
> >> header, and are not under LGPL v2.1+ explictely since it is not 
> >> mentioned in their header either.
> >> 
> >> I still don't know if we need to _explicitely_ relicense them to 
> >> LGPL v2.1+, if we want to _distribute_ FFmpeg as a "whole" as LGPL 
> >> v2.1+.
> >> 
> >> The fact that we are _allowed_ doesn't tell if we _need_ to or not.
> > 
> > I have already replied to this before.  I'm a glutton for punishment,
> >  once more:
> > 
> > libavcodec/fdctref.c is only used in a small test program.  It's 
> > nonfree anyway, but will hopefully be replaced soon.
> Hummm,
> ---------------------
> Quoting you in 2006 in:
> "[Ffmpeg-devel] overall license review - adding proper license headers
> Diego Biurrun diego at biurrun.de
> Sun Sep 3 16:18:30 CEST 2006
> > its only a tiny part of the reference code and its only used for 
> > testing and comparing our (i)dcts against it furthermore it is as
> > said not part of compiled ffmpeg libavcodec or libavformat IMO thats
> > fair use, but iam not against it if someone wants to rewrite it, its
> > very little work, just a schoolbook (i)dct
> I disagree, there is no way around the "all rights reserved".  We cannot
> distribute it in tarballs.
> Any volunteers to rewrite it?  Is dct-test still useful?"
> --------------------
> However, we distributed it within FFmpeg 0.5 tarball.
> Did you change your mind ?

No, I wanted to remove it, but I was overruled.  What was I to do?  The
problem is mitigated by the fact that it's a very small file and it's
reference code which is supposed to get around.  Also, it's probably
just a badly worded licensing statement that was supposed not to
restrict distribution and the MPEG group will never come after us due to
distributing that file.

Still, it's a problem and I'm very happy that we will likely soon
replace that file.  Once the soc student's work hits the tree, I'll put
it in the 0.5 branch and release 0.5.1 from it.

> > libavcodec/x86/vc1dsp_mmx.c is MIT-licensed.  It is not the only file
> >  under such licensing terms.  Such permissively-licensed files are 
> > compatible with all present and future versions of the (L)GPL.  There
> >  is no need to relicense them.
> > 
> > In combination, the union of all terms apply.  Since the requirements
> >  in the (L)GPL are a superset of those in MIT, the (L)GPL terms
> > apply.
> Ok, shouldn't we clarify that these files are licensed under MIT ?
> Like I already suggested it would be nice to reference these files,
> under a different license, somewhere in svn.

It would not hurt, but I consider it strictly optional.  These files do
not place extra restrictions or requirements on users that they need to
be made aware of.


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