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

Stefano Sabatini stefano.sabatini-lala at poste.it
Tue Jun 7 18:31:22 CEST 2011

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).
FFmpeg = Fantastic & Fancy Mastering Pitiless Elastic Gangster

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