[FFmpeg-devel] [PATCH] Add lut filter.
stefano.sabatini-lala at poste.it
Sun Jun 19 20:17:18 CEST 2011
On date Friday 2011-06-17 15:11:58 +0200, Stefano Sabatini encoded:
> On date Tuesday 2011-06-07 18:31:22 +0200, Stefano Sabatini encoded:
> > On date Tuesday 2011-06-07 18:16:43 +0200, Reimar Döffinger encoded:
> > > On 7 Jun 2011, at 10:34, Stefano Sabatini <stefano.sabatini-lala at poste.it> wrote:
> > [...]
> > > >> Another thought - studio level video is allowed to have excursions below
> > > >> 'black' and above 'white'. Am I right in my understanding that this
> > > >> filter will clip at black and white?
> > > >
> > > > That's correct. I did it since that was resulting in artifacts for
> > > > out-of-band values with gamma correction (this was resulting in
> > > > negative gamma-corrected values for out-of-band values). We may find a
> > > > better solution or disable clipping through an option.
> > >
> > > Shouldn't it always be possible to have the clipping explicitly in the given formula?
> > > That would make that kind of implicit clipping just a pointless limitation of what can be done with the filter...
> > Uhm maybe a clipval, but then we need to add a parameter to gammaval,
> > it will then be gamma(clip(val), gamma) or gamma(val, gamma), and
> > we may also want clip(expr), e.g. clip(gamma(clip(val), gamma)).
> > But I also want to know how out-of-band values may be used (and I
> > suppose FFmpeg may clip them anyway along the processing path).
> Updated, now the filter won't automatically clip the val in the valid
> range, but it's still possible to use clipval in the expression in
> case it is required. The gammaval and negval all use clipped values,
> the user need to specify explicitely non-clipping exression in case he
> I'm going to push the filters in few days if I see no more comments.
FFmpeg = Faithless & Fundamentalist Mortal Pacific Efficient Generator
More information about the ffmpeg-devel