Am 30.01.2023 um 12:52 schrieb Paul B Mahol:
On 1/30/23, Michael Koch <astroelectro...@t-online.de> wrote:
Am 30.01.2023 um 10:29 schrieb Paul B Mahol:
You wrote:
"With default parameters and just strength(2) set to your values, so
the darkest pixels are left untouched."
However I want that black remains untouched. That's not the same,
because
the darkest pixels in the image aren't black.
The workaround is to insert a black pixel before normalizing:
-vf drawbox=w=1:h=1:color=black,normalize
This command produces more convincing output:
-vf colorlevels=rimin=0:gimin=0:bimin=0:rimax=-1:gimax=-1:bimax=-1
this will pick max pixels values from input and stretch it do default
output max.
This command gives almost the same result as my workaround.
The meaning of -1 for options is missing in the documentation.
It has the same problem as my workaround: The output is only 8-bit.
filter supports up to 16bit rgb(a), adding float would be trivial.
patch welcome
Thanks for adding float to colorlevels.
Is there any filter for gamma correction with float?
Does the geq filter support float?
Michael
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