Kevin Wheatley: I have a fix for the table wrap issue from last week, adding an extra entry to the end of the tables. I opened a PR for that. I also tried to add support for different sized tables, but it doesn't work.
Alex Fry: The approach of inferring where the corner is seems better than using huge tables.
Kevin Wheatley: The corner is missed due to the uniform distribution. What if we used the same non-uniform distribution as for the cusp?
Nick Shaw: That uneven spacing is derived from the actual RGB values going round the edge of the cube. But the corner at limitJmax is not at exactly the same hue. Primaries and secondaries at different J values have slightly different h.
Alex Fry: I've been looking at an interpolation method which infers the position of the corner by extrapolating the intervals either side. But it seems to be moving everything a bit.
[Alex showed a plot of his corner interpolator, toggling is on and off, and showing the small shift of the whole boundary]
Alex Fry: It's actually not showing the actual output of the lookup. It is showing the boundary intersection using that reach.
Alex Forsythe: Scott has created CTL versions of v58 to provide to manufacturers as a developer release. Any changes we make from now will go into a future update. aces-dev now has a branch called v2-dev-release. The core code is a library, and there are separate repos for IDTs/CSCs, LMTs and ODTs. This is better for version control, as a new IDT or ODT doesn't necessitate a new ACES version. aces-core(the new name for aces-dev) will only change with version updates. We hope to announce the actual ACES 2.0 public release later this year.
Nick Shaw: Presumably we can push bug fixes to the CTL.
Alex Forsythe: Only critical bugs.
Kevin Wheatley: We need to make unit tests for the CTL.
Pekka Riikonen: We should port what Scott has done in the CTL back into Blink.
Alex Fry: I need to move the Blink into an AMPAS repo.
Nick Shaw: Is a special CTLRENDER build needed to run the CTL?
Alex Forsythe: You need to build from the CTL master branch using e.g. brew install--HEAD CTL. This is an important moment and a culmination of a lot of work.
Alex Fry: The Transformers One trailer came out last week, and that was done with v28 of the DRT.
Kevin Wheatley: If we back-port Scott's CTL to Blink we will have much less code, as he only took the path that is actually used. That should probably be a separate branch or directory, and what we have now becomes a dead end. But it's sill there in the history.
Alex Forsythe: Documentation is very important describing the methodology.
Kevin Wheatley: If we make a new Blink from the CTL, that's all we need to document. And we can make use of the documents Nick and Pekka have already written, updating them as needed.
Alex Forsythe: We will build the documentation in markup on https://docs.acescentral.com/. That's what we've done for e.g. the RGC. It's better than people downloading PDFs that go out of date.
[The remainder of the meeting was looking at merging Kevin's bug fix PR]
ACES Output Transforms VWG
Meeting #149, April 24th, 1pm PT
[Meeting Recording]
Attendees
Meeting Notes
Meeting #148, April 17th, 1pm PT
[Meeting Recording]
Attendees