Am 29.01.2023 um 22:05 schrieb Paul B Mahol:
On 1/29/23, Michael Koch <astroelectro...@t-online.de> wrote:
Am 29.01.2023 um 19:32 schrieb Paul B Mahol:
On 1/29/23, Michael Koch <astroelectro...@t-online.de> wrote:
Hello,
if I understood the documentation correctly, the normalize filter maps
the darkest input pixel to blackpt and the brightest input pixel to
whitept:
darkest pixel --> blackpt
brightest pixel --> whitept
However I need a slightly different mapping:
A black input pixel shall remain black, and the brightest input pixel
shall become white.
black --> blackpt
brightest pixel --> whitept
With other words: Just multiply all pixels by a suitable constant. Don't
add or subtract anything.
Is this possible?
Known workaround: Make sure that the input frame contains a black pixel,
by inserting one in a corner.
Try attached patch.
How must I set the options for the desired behaviour?
Set first strength to reverse of second strength.
So 1.0 and 0.0 or 0.0 and 1.0
I did try with strength=0:strength2=1 but the output isn't as expected.
I'm using this input image:
http://www.astro-electronic.de/flat.png
The pixel values are about 171 in the center and 107 in the top right
corner.
The center to corner ratio is 171 / 107 = 1.6
In the output image I measure 248 in the center (which is almost as
expected, probably correct because I'm measuring the average of a 7x7
neighborhood), but I measure 122 in the top right corner.
The center to corner ratio is 248 / 122 = 2.03
The corner is too dark.
Michael
_______________________________________________
ffmpeg-user mailing list
ffmpeg-user@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-user
To unsubscribe, visit link above, or email
ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
