[FFmpeg-user] Question about "normalize" filter

[Paul B Mahol]

On 1/29/23, Michael Koch <astroelectronic at t-online.de> wrote:
> Am 29.01.2023 um 19:32 schrieb Paul B Mahol:
>> On 1/29/23, Michael Koch <astroelectronic at 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

>
> Micheal
>
> _______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> ffmpeg-user-request at ffmpeg.org with subject "unsubscribe".
>