[FFmpeg-user] overlaying a clut over a picture

Michael Koch astroelectronic at t-online.de
Mon Jan 14 09:40:02 EET 2019

Am 14.01.2019 um 07:28 schrieb Michael Koch:
> When I create a color-look-up-table with this command line, the result 
> is a 512x512 clut saved as 16-bit PNG. It works as expected and I 
> checked that the top left pixel is black (R=0, G=0, B=0) and the 
> bottom right pixel is white (R=65026, G=65026, B=65026).
> c:\ffmpeg\ffmpeg -f lavfi -i haldclutsrc=8 -frames 1 -pix_fmt rgb48be 
> -y clut.png
> In the next example I wanted to extract one frame from a video, 
> overlay the clut in the top left corner, and save it as 16-bit PNG. I 
> need 16-bit PNG because my video is 10-bit. At first glimpse the 
> result looks good, but a closer examination finds that the top left 
> pixel is not pure black, it's R=0, G=1285, B=0, and the bottom right 
> pixel of the clut (at coordinates 511,511) is not pure white, it's 
> R=65535, G=63736, B=65535. Why are the colors wrong?
> c:\ffmpeg\ffmpeg -ss 5 -i P1000099.mov -f lavfi -i haldclutsrc=8 
> -filter_complex overlay -frames 1 -pix_fmt rgb48be -y Image_with_CLUT.png

I found a solution myself:  overlay=format=rgb


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