[Ffmpeg-devel] overall license review - adding proper license headers

Diego Biurrun diego
Wed Sep 6 01:06:23 CEST 2006

On Tue, Sep 05, 2006 at 04:17:47PM +0200, Benjamin Larsson wrote:
> Diego Biurrun skrev:
> >[...]
> >I'll ask you again, just in case: Are you willing to relicense the code
> >as LGPL?
> >
> >Judging from what you have written so far the answer is probably no.  In
> >this case we should go back to plain GPL on that file IMO.
> >  [...]
> I dissagre to place it under GPL only, just extend the wording so it's 
> less likely to missunderstand it. Otherwise you will remove a feature 
> from the LGPL version of ffmpeg.

It's not a feature but an arch-specific optimization, that's a difference.

The problem we're facing here is license-proliferation.  What is the
license of FFmpeg?  LGPL.  Or rather LGPL, unless you enable some parts
that are GPL and then the whole becomes GPL.

Or is it?

So what exactly is the license if libavcodec/i386/idct_mmx.c is part of
FFmpeg?  GPL?  LGPL?  LGPL with an extra clause?  Which clause exactly?
I haven't seen Michel make a crystal-clear statement yet and the note we
currently have is so misleading to be downright wrong.

This has practical implications as well.  Is another option for
configure needed?  --enable-gpl and --enable-lgpl-with-strings-attached?

And now what happens about reusability.  Can I reuse that file under
LGPL if I take it out of libavcodec?  No?  Yes?  So can I just import
all of libavcodec into my project and just compile in that file?  What
if I reuse all of libavcodec, but drop some codecs I don't need or other

You may call this removing a feature, I call it removing a legal


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