State of OCIO development re: CPU/GPU mismatches

Nathan Rusch <natha...@...>

Hello all,

This is mostly directed at those currently leading the OpenColorIO project, but I would be happy for any input or information anyone else can provide.

Most of you are likely aware of the outstanding issue that causes pretty severe banding and other visual differences in images processed using OCIO's GPU code path (documented here). This issue effectively prevents OCIO from being used in a GPU-dependent application like RV without resorting to workarounds like intermediate baking of temporary LUT files.

Because the Github repository has remained unchanged for two years now, and (more surprisingly) no one else seems to be asking about this issue in any public forums, I wanted to try and get some general information on the state of OpenColorIO development. This general question has been asked before (seeĀ this thread from November of last year), and there was mention of a large amount of new code that was about to be released, but that has yet to materialize. I don't know if there are other communication channels I'm not privy to, but to put it bluntly, the project seems to have lost its pulse.

At this point, we are seriously considering trying to fix the GPU code ourselves to make OCIO a viable part of RV. However, that post specifically mentioned that the forthcoming updates would tackle "differences between the GPU and CPU code-paths" (among other things), so if we decide to dive into that rabbit hole, I'm wondering if there would be any way we could get our hands on whatever progress has been made and get a better idea of the state of things first. Like I mentioned, I'm genuinely surprised that there aren't more people making noise about this, so at this point I have to assume that A) not enough people are aware of the problem, B) they don't consider it a serious issue, or C) they're not using RV or anything else that relies on OCIO's GPU code.

Anyway, I don't mean to come across as too doom-and-gloom, but I would appreciate any information anyone is willing to share, even if it's not very encouraging.



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