My understanding of OCIO configs and LUTs is quite limited, but having spent quite some time experimenting with the AgX approach recently, probably I can comment something.
The AgX image-formation transform (i.e. transforms from scene-referred input data to display-referred, formed image, same what filmic does in darktable) takes the following approach:
- Convert to a working space (currently Rec.709 primaries, Display P3 is being considered as a replacement)
- Clip off negatives (to be replaced by more sophisticated compression)
- “Inset” the input values toward achromatic by a bit (this is done by a matrix transformation)
- Apply per-channel RGB curves
- Optionally apply chroma and contrast changes
- (Future: expand or compress toward the destination color gamut)
Currently only the per-channel RGB curve part (step 4) is formulated as a LUT in Troy’s repo, the other things are done in the OCIO config that’s distributed in the same repo. As again I’m not very familiar with how the OCIO things work, I’m not sure if the entirety of this can be formulated as a CLF LUT. If it’s possible, would be certainly worth trying.
As for AgX itself, the “inset” part is what really sets it apart from the existing image-formation methods. It allows handling bright, saturated colors much easier.