[FFmpeg-devel] [PATCH] Enable swscale by default

Michael Niedermayer michaelni
Sun Sep 14 16:47:22 CEST 2008


On Sun, Sep 14, 2008 at 03:14:08PM +0100, M?ns Rullg?rd wrote:
> Michael Niedermayer <michaelni at gmx.at> writes:
> 
> > On Sun, Sep 14, 2008 at 02:12:00PM +0100, M?ns Rullg?rd wrote:
> >> Diego Biurrun <diego at biurrun.de> writes:
> >> 
> >> > On Sat, Sep 13, 2008 at 03:27:44PM -0700, Baptiste Coudurier wrote:
> >> >> 
> >> >> Michael Niedermayer wrote:
> >> >> > I thought it was agreed in the droping of the old scaler thread
> >> >> > that whoever wants a lgpl scaler will have to do the work.
> >> >> 
> >> >> I didn't agree _at all_ with that, and I will vote against.
> >> >
> >> > While I surely do not want to fan the flames, this has been a long time
> >> > coming - I think it's time for the LGPL faction to stand up and work...
> >> 
> >> Until last night, I was under the impression that the switch to
> >> swscale would only be done when the mmx parts were separated from the
> >> main code, and an lgpl version could be built.  It would appear that I
> >> was mistaken, if not misled.  Making the scaler and colourspace
> >> converter gpl is effectively making all of ffmpeg gpl.
> >
> > I must admit i was myself not fully aware of a few consequences of droping
> > the old scaler, like ./configure failing. Though i thought it was obvious
> > that droping the old scaler would implicate one way or another no lgpl
> > scaler until walkens yuv2rgb code was rewritten.
> 
> Why has it been repeatedly stated in the past, that the GPL-only parts
> were only needed for mmx, and that a plain-C LGPL swscale is easily
> possible, if this is not true?  If I were prone to conspiracy theories
> (and I sometimes am), I might suspect this was an underhanded attempt
> to make FFmpeg GPL without anyone noticing before it was too late.
> I'm in a good mood today, so I won't make such accusations just yet.

The only plain C GPL code that iam aware of that we need in there are
220 lines of yuv2rgb table generation code.
Rewriting this is easy, luca did it already IIRC but walken
claimed copyright on the rewritten table generator. Noone else dared to
try again and i simply have no personal interrest in rewriting FOSS code
due to its license being disliked by some other people.

Also the scaler might almost function entirely without this table generator
We by now have a almost complete plain C rgb->yuv path that doesnt need it.
Though it from a technical POV would be better to keep this or a equivalent
table generator because it means more flexibility in terms of speed vs.
quality.

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

Observe your enemies, for they first find out your faults. -- Antisthenes
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