Save LUTs as a texture

[Daykod]

My use case is for color grading HDR games for OBS, but it might be nice for game devs using unreal engine or unity.
They expect something like https://docs.unrealengine.com/portals/0/images/Engine/Rendering/PostProcessEffects/UsingLUTs/RGBTable16x1.png whereas OBS expects:

[Entropy512]

A viable workaround which I've used for Sony S-Log2 input to OBS is to take the OBS identity LUT texture and apply a cube LUT to it using ffmpeg's lut3d filters

In the long term I'm hoping to look into the feasibility of direct texture LUT export support as a level 16 Hald CLUT has much finer resolution (256x256x256 cube, or 4096x4096 texture) than any of the cube LUTs support. (I'm hoping to implement OpenCL Hald LUT support in ffmpeg in the next month or two.)

The OBS LUT format is different from the typical Hald CLUT, I'm not sure what the rationale for that was.

[monokee]

I made a free LUT converter that can output different texture formats here: https://www.color.io/free-online-lut-converter
Output -> Select Format -> PNG Textures