[FFmpeg-user] [Cin] FranceBB's LUT collection

[Mark Filipak]

On 16/05/2025 21.48, Andrew Randrianasulu wrote:
> сб, 17 мая 2025 г., 04:32 Mark Filipak <markfilipak.imdb at gmail.com>:
...
>> https://www.cinelerra-gg.org/forum/help-video/francebb-luts-for-space-color-conversions/
>>
>> Color transfer by LUT, wonderful!
>> ...
>> What do you have for '-vf'?
> 
> With  bash shell on Slackware 15.0  it works like this from home directory:
> 
> -vf
> lut3d=file=/home/guest/botva/src/src/LUTs/HLG_BT2020_to_Linear_BT709.cube

I tried a few 'cubes'. I was unsure which 'cubes' to use based solely on their names -- for example, 
what does 'linear' mean in this context -- but I eventually settled on the following:

set _BT2100_HDR_PQ_to__BT709_=^
lut3d=file='BT2100_HDR_PQ_to_BT2020_SDR.cube'^,lut3d=file='BT2020_to_BT709.cube'
...
  -filter_complex^
  "[0:v]%_UHD_TO_HD_%,%_BT2100_HDR_PQ_to__BT709_%,format=yuv420p[v]"^
  -map "[v]"^
...

The result required extensive contrast-brightness-saturation tweaking, so I obviously don't have the 
right formula. Would you care to comment, Andrew?