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

[Uoti Urpala]

On Fri, 2006-09-01 at 11:39 -0400, Rich Felker wrote:
> > libavcodec/i386/idct_mmx.c is marked as GPL but with the exception that
> > it can be used as LGPL in libavcodec.  IMO this is equivalent to
> > releasing it under the LGPL in libavcodec.  The licensing note should be
> > updated.
> 
> Yes, there is not such thing as "GPL for one particular project" or
> "LGPL for one particular project" since both these licenses allow
> unlimited relicensing under themselves. However this sort of language
> from an author is very dangerous IMO because it indicates that they do
> not understand GPL/LGPL at all and might try to attack users who

But it does make sense in the meaning "I will relicense this under LGPL
if it's included in libavcodec" when the code is not yet part of
libavcodec when writing that.

Also strictly speaking "LGPL for one particular project (and copies of
that) and GPL otherwise" IS possible - if you receive a copy from one of
those projects only then you have to follow that license. Obviously it
would in practice be LGPL if both versions are widely available, but
with limited distribution it could matter.