January 4, 2021

Host: Michael Dolan

Attendees:

• [X] Mark Boorer (TSC) - Industrial Light & Magic

• [ ] Mei Chu (TSC) - Sony Pictures Imageworks

• [ ] Sean Cooper (TSC ACES TAC Rep) - DNEG

• [X] Michael Dolan (TSC Chair) - Epic Games

• [X] Patrick Hodoul (TSC) - Autodesk

• [ ] John Mertic - Academy Software Foundation / Linux Foundation

• [ ] Carol Payne (TSC) - Netflix

• [X] Mark Titchener (TSC) - Foundry

• [X] Carl Rand (TSC) - Weta Digital

• [X] Doug Walker (TSC Chief Architect) - Autodesk

• [X] Kevin Wheatley (TSC) - Framestore

• [X] Bernard Lefebvre - Autodesk

• [X] Robin Rowe - CinePaint

Apologies:

• Carol Payne

• Mei Chu

OCIO TSC Meeting Notes

• rawtoaces:

  • Michael: rawtoaces was accepted as an ASWF incubation project at the last TAC meeting. Might be some interesting collaboration opportunity there.

• Doug to summarize in-progress work:

  • Doug: New PRs two weeks ago, some updated commits last week.

    • Grading op implementation now complete.

    • Minor fixes/changes: v1/v2 serialization issue (#1244). to_reference/from_reference synonyms. Default view transform specification.

    • #1241 implements color space alias feature.

    • Michael: Use case for config name added in PR? Comment seemed to imply could be used as a color space namespace, and referenced externally?

    • Doug: Optional config name, could be useful for:

      • Alternative to filename for tracking config.

      • Indicate version.

      • Future use as more fully qualified name for a color space.

      • Reference for USD, other projects, etc.

    • Just metadata for now.

    • TODO: Bernard will clarify comment in API that config name has no influence on color space lookups.

• Seeking approval to merge PRs #1220, 1234, 1241 (today), 1244, 1245 (tomorrow):

  • Doug: Want to get OCIO v2 out there, since we're over the VFX ref platform release date a bit. Suggest releasing 2.0.0 by mid-January. Want to get last PRs merged and RC tag to communicate final testing state.

  • Michael: Have a Python binding fix for CPUProcessor that should be in RC release.

  • Mark: Did apphelpers (#1220) add dependecy to core? OpenGL?

  • Doug: No, that's in another helpers lib separate from core.

  • No objections to proposed merges.

• Version handling discussion:

  • Doug: Once config v2 version starts getting used, will be need to bump version for future changes. Want to discuss how to handle versioning. If config syntax needs tweaking, what to do. Currently will throw for v3 and warn for v2.1.

  • Michael: Currently just single int right?

  • Doug: Yes, and added ability to have minor version in OCIO v2.

  • Kevin: What additions would we make to need a version warning? Fixed transform?

  • Doug: Yes, and some things would throw. A new style string for a transform for example.

  • Mark: Don't think there's need to be future compatible. Would prefer to fail fast vs. silently ignoring incompatibility. OCIO and config version numbers can diverge.

  • Patrick: For debugging would be useful to keep major version in sync between lib and config.

  • Kevin: Does the minor version increment sequentially, or is it tied to lib release? Under what circumstances is a warning valid. Or is it just valid or not valid, ok or throw.

  • Doug: If an older version config is not using new features, it could try to load.

  • Michael: Failing fast would avoid subtle differences, like ExponentTransform negative handling changing for example.

  • Kevin: Or changed defaults.

  • Michael: Could have metadata in config with exact lib version if needed.

  • Patrick: Need to be careful with optional metadata. Could get out of date and be confusing.

  • Mark: If having minor version helps keep it organized, have no problem with it.

  • All agree to allow minor version, and fail on unknown/unsupported version rather than raising a warning.

  • TODO: Bernard will push updated to #1244, which is related.

• Discussion about creating a RB-2.0 release branch:

  • Doug: After these PRs get merged, will create the branch. Should RC tag begin that?

  • Kevin: If we create them together we are saying they are the same. If separated, might be different.

  • Patrick: Where do we put the tag? In master or in RB-2.0?

  • Mark: Have it in both, and cherry pick master changes into RB-2.0.

  • Patrick: Only consequence is master will be tagged as RC.

  • All agree to create tag in master and branch RB-2.0 from that.

• General discussion:

  • Kevin: If we are concerned with ABI compatibility, should we put something in place to warn about it? Extra symbol appears or disappears, etc.

  • Mark: OCIO is good at avoiding this since all symbols have version namespace. Only issue if you don't update the version number.

  • Patrick: If we are consistent, won't happen. Should be caught in review.

  • Mark: Difficult to comare symbols to detect change. Would need two builds or maintained list of symbols.

  • Patrick: Even changing order could be an issue.

  • Kevin: What about for Python?

  • Michael: We are setting version currently.

  • Mark: It is likely used in setup.py, etc.

  • Michael: We will eventually setup PyPi, so could be used there too.

  • Follow up: See PEP 396: https://www.python.org/dev/peps/pep-0396/