[Ffmpeg-devel] moving non-SIMD parts of libswscale to LGPL

Michael Niedermayer michaelni
Tue Nov 14 14:06:57 CET 2006


Hi

On Mon, Nov 13, 2006 at 03:59:52PM +0100, Michel Bardiaux wrote:
> Reimar D?ffinger wrote:
> >Hello,
> >On Mon, Nov 13, 2006 at 12:35:42PM +0100, Michel Bardiaux wrote:
> >>Diego Biurrun wrote:
> >>>On Mon, Nov 13, 2006 at 11:39:19AM +0100, Michel Bardiaux wrote:
> >>>>What are the plans for the SIMD parts?
> >>>Leave them as GPL.
> >>From the first day there was talk of swscale, I was afraid it would end 
> >>like this. With the removal of img_resample and that licensing, the LGPL 
> >>version becomes a second-class implementation.
> >
> >It does not change the current situation at all, so I don't see a reason
> >to be much annoyed over it.
> 
> Only if the pure-C swscale is faster than img_resample with the MMX 
> optimisations.
> 
> >
> >>There is not much I can do, but I dont have to like it.
> >
> >There is a lot you can do, like writing LGPL SIMD or trying to convince
> >the authors to allow relicensing as LGPL. 
> 
> Difficult to do both: to contact the authors, one has to dig in the 
> sources, but to rewrite a LGPL version of the SIMD code, better keep a 
> 'clean room' approach. But the latter is likely to be impossible, so 
> there is no solution.

what f* SIMD code are you talking about anyway
there are ~2 pages of mmx code in libavcodec/imgresample.c from which
one is under if(0)
and the code is crap, most mmx insructions work with one single sample
actually i wouldnt be surprised if the c code in imgresample.c where faster


[...]
> >and towards the
> >authors, you can't expect others to argue for something that is not
> >their goal...
> 
> If someone's goal is to force a mutation of the license to GPL, that is 
> not acceptable.

as diego said acceptable by whom?
if we choose to change the license to GPL then so be it, actually any
single person can fork ffmpeg and change it to GPL and continue development
on that GPL version, iam quoting the LGPL for you below

  3. You may opt to apply the terms of the ordinary GNU General Public
License instead of this License to a given copy of the Library.  To do
this, you must alter all the notices that refer to this License, so
that they refer to the ordinary GNU General Public License, version 2,
instead of to this License.  (If a newer version than version 2 of the
ordinary GNU General Public License has appeared, then you can specify
that version instead if you wish.)  Do not make any other change in
these notices.

  Once this change is made in a given copy, it is irreversible for
that copy, so the ordinary GNU General Public License applies to all
subsequent copies and derivative works made from that copy.

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is




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