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

Discussions - ACESNext VWG – Gamut Compression/Mapping
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ACES Gamut Compression Implementation VWG Meeting #15

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

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Gamut Compression Implementation Virtual Working Group

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Recap:

  • 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