ACES Settings ODT


(Dean Du C.S.I.) #1

Hi,
Some time ago saw ACES launched the “Interactive wireframe of a parametric ODT concept” page,
After the trial there are some questions,
I see export options, but after I set the parameters, click and did not respond
Is it not yet open export function?
Follow-up can use the export function?
What is the format of the exported file, whether DaVinci Resolve is supported


(Alex Forsythe) #2

@Dean this is all conceptual at the moment. This wireframe is only intended to be an example of how a single, parametric ODT might be presented to an end user. My thought with the export was that all the settings selected would get written into some kind of file. I think it makes sense to specify that file format for the sake of cross system compatiblity but we’ve been more focused on the algorithms themselves for now. What are your overall thoughts of the parametric ODT concept?


(Dean Du C.S.I.) #3

I’m very sorry to reply you so late
Recently it is too busy
The concept of parametric ODT, very good,
It is a good support for our colorists to deal with the constantly updated color coding,
Now this parameterized ODT framework, I think itself is already very reasonable and easy to understand
However, I do not understand the algorithm, may be in the custom which will prefer simpler settings can export the ODT
For example, I want to derive a dolby vision P3-DCI ST2048 48 nits XYZ ODT
When I set it to Output Transform Tone Scale
18% Gray Luminance inside the parameters, I do not know how much is correct
It is possible that this parameter has different values for different color spaces and gamma
The future in the help document, there will be different color space and gamma corresponding to the correct value of 18% Gray Luminance
Or easier to set the parameters of such
I hope my suggestions will be helpful in designs for parametric ODT


(Alex Forsythe) #4

Hey @Dean

Scott posted some Python code over here that provides an interactive example of the tone scale algorithm we’ve been playing with. Basically you have a few controls. Max and min luminance are the maximum and minimum luminance values of the display you’re using. The 18% gray luminance is the luminance at which you’d like to reproduce an ACES value of 0.18. With the current P3 48 nit max ODTs ACES=0.18 gets reproduced at 4.8 nits on the display. This was a choice … it could be moved up or down from there by shifting the entire tone scale left or right on the log / log plot. 10% of max luminance seemed about right for SDR, but with HDR the proper level is less clear. One can use the extended display dynamic range to increase the overall luminance of the image, display more highlight dynamic range from the scene, or a little of both. Give @sdyer demo a try and let us know what you think.