Applying 256x16 LUT?

[YorVeX]

I am trying to replicate the color grading from Snap Camera in OBS. There is a base LUT file here that I believe would be the right one. However, it's a 256x16 pixels file which has 16 "fields" all in one line (16x1) - that means 16x16 pixels per field.
The LUT files that OBS can use with the "Apply LUT" filter are 512x512 pixels and have 8x8 "fields" - which means it's 64x64 pixels per field.

Any idea how I can convert this in a way so that OBS can work with it? I tried to scale the original fields up and redistribute/duplicate them so that they fill the 8x8 fields but the result is nowhere near what it should look like (I didn't really expect this to work but well, I had to try at least...)

Any other way to either replicate the color grading or reverse that from Snap (probably even harder, not all LUT changes can be reversed) would also be welcome. Just for reference, here is an example picture before and after Snap Camera applied its color grading to it.

 

[Suslik V]

It is far easier to load OBS neutral LUT image file into the required application and make screenshot of the output - modified LUT is ready!

As for the "before" and "after" example images - it turns out that they are very close to the BT.601 vs BT.709 hell. Such OBS LUTs already exists:

Some useful color correction LUTs in PNG format (and few info on them) you can find at this post: https://obsproject.com/forum/threads/chroma-shifting-for-video-game-capture.69337/#post-299246

You need the "601_to_709.png" LUT to be applied to the "before" image to enhance green (back true 601 colors while on 709 system).