[FFmpeg-user] red-shift and blue-shift

[Mark Filipak]

On 03/04/2020 07:05 AM, Michael Koch wrote:
> Am 04.03.2020 um 12:44 schrieb Mark Filipak:
>> On 03/04/2020 05:52 AM, Michael Koch wrote:
>>> Hi,
>>>
>>> is there any known workaround for making a red-shift or a blue-shift? 
>>> I mean shifting the visible spectrum towards red or blue. In the 
>>> middle of the spectrum this can be realized by the "hue" filter, but 
>>> at the end of the spectrum I want a different behaviour. I want a 
>>> shift instead of a rotation. Colors at the end of the visible 
>>> spectrum must be shifted to (or from) black.
>>>
>>> Michael
>>
>> Hey, Michael, (seriously this time), can't you diddle luminance at the 
>> same time as hue?
> 
> As far as I know, there is no filter for decreasing the luminance as a 
> function of hue.
> Although a complicated workaround with "geq" filter might be possible. 
> I'll try to figure it out.
> 
> Michael

Seems to me you need a passband filter with Gaussian roll-offs.