Notice of Meeting - ACES Gamut Compression Implementation VWG - Meeting #15 - 07/08/2021

ACES Gamut Compression Implementation VWG Meeting #15

Thursday, July 8, 2021
9:30am - 10:30am Pacific Time

Dropbox Paper link for this group:

Gamut Compression Implementation Virtual Working Group

We use the same GoToMeeting URL and phone number for all virtual working group meetings.
You may join via computer/smartphone (preferred) which will allow you to see any presentations or documents that are shared or you can join using a telephone which will be an audio only experience.

Please note that meetings are recorded and transcribed and open to the public. By participating you are agreeing to the ACESCentral Virtual Working Group Participation Guidelines

Audio + Video
Please join my meeting from your computer, tablet or smartphone.

Audio Only
You can also dial in using your phone.
Dial the closest number to your location and then follow the prompts to enter the access code.
United States: +1 (669) 224-3319
Access Code: 241-798-885

More phone numbers
Australia: +61 2 8355 1038
Austria: +43 7 2081 5337
Belgium: +32 28 93 7002
Canada: +1 (647) 497-9379
Denmark: +45 32 72 03 69
Finland: +358 923 17 0556
France: +33 170 950 590
Germany: +49 692 5736 7300
Ireland: +353 15 360 756
Italy: +39 0 230 57 81 80
Netherlands: +31 207 941 375
New Zealand: +64 9 913 2226
Norway: +47 21 93 37 37
Spain: +34 932 75 1230
Sweden: +46 853 527 818
Switzerland: +41 225 4599 60
United Kingdom: +44 330 221 0097


  • OCIO PR: @matthias.scharfenber - curious about the low bound value for the threshold being 0.4 - for the FixedFunction, shouldn’t that be 0 or very near 0?
    • Starting with smaller bounds may be better, we can always expand later and not break backwards compatibility.
    • @KevinJW: unless there’s a very good mathematical reason, we shouldn’t impose limits. We should tell the users what the parameters are.
    • @matthias.scharfenber : these are discussions we need to have later, once we have the reference implementation is good to go.
    • @KevinJW : we shouldn’t clamp a value without telling the user in an API. If you pass 1 but the limit is 1.001, you should get a warning
  • AMF Demo:
    • @ptr gave a quick AMF intro, so the group is caught up.
    • Then showed an example AMF with the Reference Gamut Compression included
    • RGC would be right after the IDT, users wouldn’t be able to change the location in LiveGrade
    • @jzp pointed out a readability issue with the CDL op in AMF, not relevant to our group but if you’re interested in the discussion, please refer to the recording.
    • @mario: do we support the inverse of the gamut compression in AMF? How would that work?
    • @matthias.scharfenber : it could be supported, you would just specify the inverse CTL instead
    • @nick : it’s just a flag right now, we would need to separate them
    • @carolalynn : tricky bit is the software knowing where to put that inverse?
    • It all goes back to needing a “do work here” flag in the AMF
    • @Giardiello : if you get an AMF with a CLF in between the IDT and the RGC, what will happen?
    • @ptr : yeah, that will be per-vendor to handle, but we may be able to come to a general agreement about what we support and what we don’t.
  • Stubs for the Implementation Guide and User Guide
    • Please feel free to put thoughts and things in both, don’t worry about it being well written, these are living documents for now and we’ll organize later

Recording / Transcript