February 16, 2021

Host: Michael Dolan

Attendees:

  • [X] Mark Boorer (TSC) - Industrial Light & Magic
  • [X] Michael Dolan (TSC Chair) - Epic Games
  • [X] Carol Payne (TSC) - Netflix
  • [X] Doug Walker (TSC Chief Architect) - Autodesk
  • [X] Dennis Adams - Sony
  • [X] Christophe Brejon
  • [X] Zach Lewis - Method
  • [X] Scott Dyer - A.M.P.A.S.
  • [X] Kevin Wheatley (TSC) - Framestore
  • [X] Thomas Mansencal - Weta Digital

OCIO Configs Working Group Meeting Notes

  • ACES reference config PR and build update:

    • Thomas submitted PR #11 for generating ACES reference config: https://github.com/AcademySoftwareFoundation/OpenColorIO-Config-ACES/pull/11
    • He also updated the Google sheet with current naming and pivot table: https://docs.google.com/spreadsheets/d/1SXPt-USy3HlV2G2qAvh9zit6ZCINDOlfKT07yXJdWLg/edit?usp=sharing
    • Noted in discussion:
      • Currently using "No tonescale", suggest changing to use "Un-tone-mapped" naming agreed upon for OCIO lib.
      • Suggest adding "Raw" shared view.
    • Michael and Thomas noted that choosing output color spaces in an OCIO v2 config requires extra care due to needing a specific view transform, display color space combination. Will require education and extra documentation for how to get each ACES output transform. Need to take care to use display/view to bake output rather than a target color space.
    • Doug: Can also use DisplayView transform in color space if needed to simplify.
    • Thomas: Review of PR appreciated. Was an error prone exercise so good to have second set of eyes on the details. Will be critical to setup image based CI for validating transform results against CTL.
      • Doug: Will check. Note that some ACES reference images don't perfectly match CTL, noticed while testing builtin transforms.
      • Carol: There is a known bug with AP0 to AP1 CTL where it clamps.
      • Kevin: Also a clamp in ADX CTL.
      • Thomas: Can submit PR to aces-dev with improvements to help config generator, and add missing CSC transforms (Venice). Can base config build on that branch for now if needed. ACES TAC meeting is tomorrow. Can raise any concerns there too.
      • Scott noted in Slack that he will sync up with Thomas about resolving any pending PRs to aces-dev.

  • Studio config worksheet:

    • Google sheet for pruning/adjusting current ACES 1.2 config color spaces for upcoming studio config: https://docs.google.com/spreadsheets/d/1GB0LTJhf67NYb0GSc3yluac90yIY0bW2O58SWQxHts8/edit?usp=sharing
    • Michael: Folded alias color spaces into aliases column and did initial encoding assignment based on GH issue #1031. We can now choose what to include and supplement data as needed.
    • Michael: Do we want to make this backwards compatible with current 1.2 config?
    • Mark: Limiting ourselves to do that. Hard to escape earlier problems.
    • Carol: Start with essentials and then get feedback on missing spaces. Can also note the spaces that are already in ref config.
    • Kevin: Number 1 complaint, even without added alias color spaces, is too many color spaces. What's missing from reference config? What's the minimum list we need?
    • Carol and Thomas note that certain camera IDTs are missing.
    • Mark: Most of what's not needed is legacy stuff.
    • Carol: And ACES emulations under utilities.
    • Kevin: DGI D-Gamut is missing.
    • Carol: New Resolve color spaces should be added, and FilmLight E-Gamut.
    • Michael: Utility curves can be moved to NamedTransforms
    • Kevin: Are we going to exclude spaces or make them inactive?
    • TODO: Group to decide whether inactive color spaces and aliases should be added for backwards compatibility.
    • Michael: Note that what we do include needs to be implemented without adding new builtin transforms if we want usage before VFX ref platform CY2022. ACES 1.3 for example.
    • Doug: Yes, they will require minor version bump.
    • Mark: LUT-less goal more for ref config. LUTs ok in studio config.
    • Thomas: Shouldn't be hard to add these remaining color spaces to config generator once we decide what to include.
    • Zach: color spaces default to uniform allocation. If need to bake traditional LUTs, should we add alloc vars?
    • Doug: Only baker using them is CSP format.
    • Zach: Specifying shaper spaces enough to resolve it?
    • Kevin: Shaper space for generic cases in old version aren't necessarily what you want for LUT, because shaper too wide of range - for negative and over-1 handling.
    • Michael: Reasonable alloc vars will be needed to maintain legacy GPU rendering behavior.
    • TODO: Group will edit Google sheet between now and next meeting to decide on scope of studio config. Can modify include/exclude/NamedTransform flag and add missing spaces, etc. Please also comment as needed in sheet with questions and discussion points.

  • Slack question about ACES 1.2 config:

    • Doug: Question from Estaban in Slack. Looking for ACES 1.2 config.
    • Thomas: Will answer him. Zip file in colour-science OCIO-Configs fork with config package: https://github.com/colour-science/OpenColorIO-Configs/releases/download/v1.2/OpenColorIO-Config-ACES-1.2.zip
    • Doug: Can also mention we're working on OCIO v2 config.
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