ACESlog Strawman Proposal

[daniele (Daniele Siragusano)]

Hi Matthias,

let me defend the linear toe for ACEScct by referring to this post:

Why grading in log instead of linear?

Hi, the whole subject is a bit more subtle: The ideal space for an operation depends on what you want to simulate. If you are after modelling physical phenomena, then some sort of scene linear is probably the right domain. If you want to model perceptual phenomena, then typically a perceptual space (like a quasi-log or opponent space) is the right thing. Some example: If you want to do white balance/exposure, multiplication in the linear domain is the right thing to do. If you are after …

I think one primary use-case is an encoding for integer representation, like on a SDI signal on set.
If we would drop this requirement for integer encoding, the proposal would look very different, I guess.

I agree we need to collect more use cases. Do people really send ACEScct over the wire?
Or are cameras sending their own encoding over the wire, and the onset grading software converts the signal to ACEScct, then applies CDL grading and converts back to the camera encoding (or even going straight to display referred)?

If the latter would be the use case, then one could argue that we have no issue with ACEScct.

Or are we looking for a LUT shaper space?
Or a new grading space?

We should also priorities the different use cases because their solution asks for contradicting behaviour.