[FFmpeg-user] Saturation adjustment only in some channels

[Martin Cracauer]

Cl??ment B??sch wrote on Thu, Jan 02, 2014 at 09:29:55AM +0100: 
> On Wed, Jan 01, 2014 at 08:39:20AM -0500, Martin Cracauer wrote:
> > Stefano Sabatini wrote on Wed, Jan 01, 2014 at 01:21:07PM +0100: 
> > > On date Tuesday 2013-12-31 15:24:16 -0500, Martin Cracauer wrote:
> > > > I am doing color corrections on a video.  Used gimp to find the
> > > > correction adjustments.
> > > > 
> > > > I have two difficulties:
> > > > 
> > > > 1) I need to apply saturation only to cyan (leave red alone). This
> > > >    isn't directly supported by the hue filter.
> > > > 
> > > > 2) how do I clip a color? (the equivalent of using gimp color levels
> > > >    and moving left or right slider, or in color curves move one end of
> > > >    the curve on the x axis) I think it works reasonably fine but just
> > > >    pushing the highs of the color, can somebody confirm that.
> > > > 
> > > > In general, how do ffmpeg's colorbalance filter's ideas of low, mids
> > > > and highs translate to color curves? How much overlap do they have?
> > > 
> > > colorbalance and colorchannelmixer filters may help.
> > 
> > Yes, that's what I'm using.  They don't allow you to mess with the
> > saturation in some channels only, though, and colorbalance's semantics
> > when it comes to how wide it considers "mids" are a bit unclear.
> > 
> 
> See the curves filter: http://ffmpeg.org/ffmpeg-filters.html#curves-1

Thanks.  I think this will fix my problem that lifting the mids blew
out the highs.

Any ideas about per-channel saturation?

Martin
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Martin Cracauer <cracauer at cons.org>   http://www.cons.org/cracauer/