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2025-04-07 OCIO Working Group Meeting notes

2025-04-07 OCIO Working Group Meeting notes

Owned by Carol Payne, created
Apr 08, 2025
2 min read

 Date

Apr 7, 2025

 Participants

  • Carol Payne (TSC Chair) - Apple

  • Doug Walker (TSC Chief Architect) - Autodesk

  • Remi Achard (TSC) - DNEG

  • Cuneyt Ozdas (TSC) - Autodesk

  • Kevin Wheatley (TSC) - Framestore

  • Zach Lewis (TSC)

  • Joseph Goldstone

  • Daniele Siragusano - Filmlight

  • Nick Shaw - Antler Post

  • Cody Cuellar - Adobe

  • Scott Dyer - AMPAS

 Discussion topics

Item

Notes

Item

Notes

Gamma 2.2 / sRGB Displays

  • https://github.com/AcademySoftwareFoundation/OpenColorIO-Config-ACES/issues/145

  • Studio Config will get the gamma 2.2 display

  • Should the CG config config get it as well?

  • Daniele and Carol say yes, might be confusing without it in both

  • Naming:

    • Carol & Doug: sRGB in OCIO has always been the piecewise function, so it is important to keep that consistency

    • Propose calling it something like Gamma 2.2 Rec.709 - Display

    • Group is ok with this because of legacy, though Daniele and Kevin note it may still be confusing for users that interop with other applications

  • Display P3 - piecewise or gamma 2.2

    • Number of people have measured the default Apple XDR display, close to Gamma 2.2. True for iPhone as well, and also likely older Color LCD

    • OCIO spoke with folks at Apple about which transfer function to use. The response was that it is the piecewise sRGB transfer function.

    • This lines up with what is measured in the reference mode.

    • We would definitely like to avoid what has happened with sRGB with Display P3.

    • Daniele - we should be making images as correct on displays as we can, which for Apple XDR default displays, is a gamma 2.2 response

    • Would like to hold for a bit on this for Display P3 specifically, to try to get folks on the same page. Will get a response as soon as possible, or if we don’t, make plans for the 2.5 release in the Fall.


Embeddable Colorspace metadata for media export

  • https://github.com/AcademySoftwareFoundation/OpenColorIO/issues/1975

  • Cody: Need a way to export, specifically from PS, the ability to link OCIO view/display to an ICC/CICP values. Right now, artists have to choose manually from lists which is error prone and time consuming

  • We recognize this isn’t a 100% solution - i.e. BT.1886 - some people use 1-1-1, some use 1-2-1 to not infer the gamma - but it’s a start

  • We should treat the addition of the ability to have this metadata separately from the discussion of what is the “correct” metadata - i.e. making this metadata available generally, vs what might eventually make it into the Studio/CG config as “vetted”.

  • Also OS-based “enum” tagging would be useful for windowing in applications

  • We could just add a “display metadata” blob list, and add things as key value pairs as we need/want.

  • Possible to look at file input later - but likely utilized by file rules to give config authors control

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