[FFmpeg-devel] [PATCH] Add negate filter.

[Stefano Sabatini]

On date Monday 2010-11-29 02:11:23 -0800, Jason Garrett-Glaser encoded:
> On Mon, Nov 29, 2010 at 2:06 AM, Stefano Sabatini
> <stefano.sabatini-lala at poste.it> wrote:
> > On date Monday 2010-11-29 00:00:06 -0800, Jason Garrett-Glaser encoded:
> >> Just a thought here -- there's a practically infinite number of simple
> >> filters like this (i.e. filters for which every pixel is operated on
> >> independently). ?Would it not be better to port something like
> >> Avisynth's MT_LUT filter, which allows the user to specify a
> >> mathematical operation to create a LUT from, which is then applied to
> >> all pixels?
> >
> > Uhm, something like the applyfn filter I posted yesterday?
> 
> Doesn't use a LUT as far as I can see, so it's way too slow to be
> usable for much of anything.

It can't use a lookup table because the computed value is a function
of (X,Y), which allows interesting applications, but we could write
another variant of the filter.

I'm also interested in implementing other "generic" filter, e.g. a
linear convolution filter taking the kernel matrix in input and an
affine transformation filter like this one proposed by Daniel Taylor:
http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2010-April/087190.html
 
> I would think that the "naive" negate would not be much faster than a
> LUT-based applyfn...

Indeed...
-- 
FFmpeg = Frenzy and Funny Murdering Programmable Enchanting Gospel