2021-07-12

Owned by Michael Dolan
Last updated: Jul 12, 2021
3 min read

July 12. 2021

Host: Michael Dolan

Attendees:

Mark Boorer (TSC) - Industrial Light & Magic
Mei Chu (TSC) - Sony Pictures Imageworks
Sean Cooper (TSC ACES TAC Rep) - ARRI
Michael Dolan (TSC Chair) - Epic Games
Patrick Hodoul (TSC) - Autodesk
John Mertic - Academy Software Foundation / Linux Foundation
Carol Payne (TSC) - Netflix
Mark Titchener (TSC) - Foundry
Carl Rand (TSC) - Weta Digital
Doug Walker (TSC Chief Architect) - Autodesk
Kevin Wheatley (TSC) - Framestore
Sergio Rojas

Apologies:

  • Mark Titchener

  • Mark Boorer

  • Patrick Hodoul

OCIO TSC Working Group Meeting Notes

  • Review of 2.1 milestone:

    • https://github.com/AcademySoftwareFoundation/OpenColorIO/milestone/5

    • Release summary:

      • Patrick is on vacation until August. Once he returns there are some additional PRs to cherry pick commits into RB-2.0 for a 2.0.2 release, which is intended to provide bug fixes and improvements for implementers of OCIO v2.0 (VFX CY2021). Following that release a new RB-2.1 branch will be created to facilitate 2.1.0. The milestone is currently 25% complete, with some of the work in PR now.

      • The goal is to hit the August deadline for VFX CY2022, but there is some active TAC discussion about whether that date can be pushed to later in the year. Doug and Patrick are working on OSL support to facilitate MaterialX and OCIO interoperability (see issue #1435), which they hope to complete in time for the 2.1.0 release if possible. We will need to balance honoring VFX Ref Platform CY2022 deadlines with including new features. Other ASWF projects may have later release schedules for their 2022 contribution, so we may have additional flexibility.

    • OSL support:

      • Doug: There are differences between GLSL and HLSL, so current shader generation code abstracts that and calls functions. That's what looks at language. Think we can implement all ops with that same sort of approach. OSL is close. Tricky part is support for LUTs and dynamic properties.

      • Michael: Think omission of dynamic properties is fine in OSL. Different context for use compared to GLSL/HLSL.

      • Doug: Agree, LUTs is the tricky part. Talking with OSL about it and they are supportive of direction being taken. LUT support not in 2.1. Thought process is that most MatX users would be using CG config color spaces. None of those spaces require LUTs.

      • Michael: Is this a sufficient solution long term?

      • Doug: Right now MatX has default color management platform. Minimal color spaces. Think current approach would work.

    • Gamut compression transform:

      • Group agrees PR is ready to merge.

      • Kevin: Limits should be documented.

      • Michael: Currently documented with comments in the OpData cpp code. Could be put somewhere else in later PR.

      • TODO: Document parameter limits in RST or public header docstring.

    • Imath 3 support:

      • Michael: PR is ready for review. Uses Imath 3 by default, but can optionally use IlmBase 2.

      • Doug: Imath has new half implementation that uses native algorithm instead of LUTs, which would be faster. Was discussed on openexr mailing list.

      • TODO: Michael will look at CMake option to enable this, or Imath 3.1 if it's a new feature for next minor release.

  • ASWF open source days:

    • OCIO talk is Wednesday August 4, 10am-10:40am PDT.

    • Carol will talk about new gamut compression implementation. Doug may give a high level overview of OSL support.

    • TODO: Michael to provide slide deck for talk preparation.

  • OCIO conformance program

    • Michael: John Mertic reached out about possibly setting up an OCIO compliance program, like the ACES logo program. Could be partially based on UX guidelines in development.

    • Kevin: Sounds like a good idea

    • Carol: Would love to help work on that. Would be good to work together with ACES.

    • Kevin: Specification could include supported features, UI, etc.

    • Doug: Planning on submitting a PR in connection with CLF implementation working group soon. OCIO is being used heavily for implementation package being provided. Includes implementation guide, collection of CLF files to test with, reference images. PR will adjust current test CLF. OCIO CPU/GPU renderer are within tolerance of implementation guide. Includes Python scripts to compare them, etc. When it releases in next month or two, will share with OCIO group.

    • Michael: Might be a good example for OCIO UX guidelines too.

  • Items for next meeting agenda:

    • Talk with John Mertic about OCIO conformance program.