ACES 1.3 Reference Gamut Compression URN incorrect

[reinecke]

In the Reference Gamut Compression CTL, the following URN is used:
urn:ampas:aces:transformId:v1.5:LMT.Academy.GamutCompress.a1.3.0

However, guidance to implementers has been to use:
urn:ampas:aces:transformId:v1.5:LMT.Academy.ReferenceGamutCompress.a1.v1.0

This unfortunately:

1. Makes it difficult to reason about what the canonical source is for transform URNs
2. Makes it difficult to build automated tooling to maintain accurate transform libraries with URN mappings

I suggest:

1. The URN in the RGC CTL be updated to match the current best practice URN
2. A release/tag be created for ACES 1.3.1 with this update

This allows tooling to walk the release tags and and discover the new preferred transform URN as well as make sure the git repo maintains a canonical truth of that URN existing.

While this particular issue should clear up with the migration to ACES 2.0 and the new ACES URN scheme, ACES 1.0 is still the system that the vast majority are running on and I think that this change is worthwhile because there is still some time before ACES 2.0 will become ubiquitous in show workflows. Additionally, having the preferred URN recorded in this git repo will aid in resolving in future archival cases.

[scottdyer]

As of 2.0, the Reference Gamut Compression CTL lives in the aces-look repository: https://github.com/ampas/aces-look/tree/main/reference_gamut_compression
The transformID has been updated to the v2 urn and format.

I was unaware that they had included the URN in the documentation, which is now outdated. I will add that to the updates I have in progress to get documentation up-to-date with 2.0 changes.

If it is necessary for your workflow with 1.3 transforms, I could go back and make a branch off of just before ACES 2 changes were merged in and tag it v1.3.1.

[scottdyer]

If it is necessary for your workflow with 1.3 transforms, I could go back and make a branch off of just before ACES 2 changes were merged in and tag it v1.3.1.

Ah, yes, I see now that right after the 1.3 tag, this was cleaned up but no additional tag was made. I could push a 1.3.1 tag at d3d4df5 if its helpful for you.

[reinecke]

Oh, that would be quite helpful!
I like the direction all the repo re-organizations have been going, but unfortunately it's made it a bit difficult to track the lineage of some of these - the tags have been really helpful navigating that.

Thanks for the help!

[scottdyer]

Added.
https://github.com/ampas/aces-core/releases/tag/v1.3.1