ACES .exr export sony slog3 sgamut3 ODT and H264 sRGB vs Rec709

Report · Nov 20, 2023

Hello guys yesterday I was testing some workflows in Aces between davinci, nuke and ae.

I came a across a strange thing:

In AE I can correctly import and interpret an slog3-sgamut3 from a sony alpha 7s but when I try to write out an .exr sequence I cannot choose the same IDT (slog3-sgamut3). Is it normal? I can use aces cg or 2065-1 and for me it's not a big deal but I think it is strange. I am quite sure that some time ago I succeded in doing this but at this point I am start thinking I mixed the IDT with the ODT..

does anybody know about this more than me?

Another question that is around my mind is since my final output would be H264, how should I work in ae?what is the correct worflow? can I do the grading in sRGB by setting the display color space in sRGB?

becaus I know (correct me if I am wrong) that you cannot set sRGB in H264 beacuse it always get Rec709. I could switch the comp and display color space in Rec709 but my monitor would be always in sRGB... I have a mess in my mind... can anyone suggest me a proper workflow?

Thank you very much!

Mario

thank you! Mario

Report · Nov 20, 2023

Hey there,

Can't add much more info than I already posted for you on ACESCentral about sRGB/709. But regarding your other question.

EXR isn't really designed to store log encoded data but rather linear. If you need to export your comps in log I would recommend an integer format like .dpx 10bit or if you prefer single files ProRes4444/DNxHR444.

If the colorist/DI really wants exr, do ACES2065-1 instead. This is the ACES interchange format if you work with ACES by the book. Although some facilities prefer to keep the interchange as ACEScg internally for convenience with CG and the default scene-linear space in comping.

But regarding your specific issue. The full color space list of OCIO should always be available. What do you see on the Color tab in the Output Module? OCIO configs do not have a concept of IDT / ODT. It's just a list of color spaces and display spaces that you can convert to and from.

Report · Nov 20, 2023

Thank you Shebbe! I am watching right know the video you posted about the sRGB, again thank you!

Well I've been toold that I should keep the same profile from the camera but at this point I am thinking it was just a personal preference the guy has.

From my knowledge I'd stick to AcesCG but is there a specific workflow when comes to give the scenes to the colorist? I am trying to establish a workflow for my company and from my knowledge I'd go for .exr sequences at every stage of the pipeline... but I'd relly love to know if there are other better ways.

I attached the screenhot of what I see from the topdown menu in the color tab. I render the mp4 straight out of after effects render queue. When I interpret footage in override media color space I can correctly set the IDT for the sony footage.

I am using AE 23.2.0 build 65 on windows 11 pro 22h2 64bit

Thank you for your time!

Report · Nov 20, 2023

When it comes to workflows there are no standards or rules. Just guidelines to preserve as much of the captured quality wherever possible. That simply means apply as little compression at every step as long as that's suitable for your needs. If you do a lot of intermediate exports but you do uncompressed, filesizes will skyrocket so you'd need a lot of storage. In general it makes sense to try to do as much as possible without prerendering. When it comes to file formats, this is also down to preference. Most colorists prefer to get the image in the same shape as the original cam file, typically log. But a workflow where comp files are always in ACEScg or camera linear (SGamut3.cine - Linear for example) can also work.

I see you're using the ACES 1.2 config. Perhaps there you have to check [show all] to see the other spaces. With OCIOv2 ACES 1.3 it's the other way around, you'd need to enable it to see the display spaces.

The way Adobe made this work is a bit unpractical and I've already asked for improvements there. The way Nuke handles this is what we'd actually need and exactly what I suggested before they even implemented it.

Report · Nov 20, 2023

But a workflow where comp files are always in ACEScg or camera linear (SGamut3.cine - Linear for example) can also work.

I should add, regardless of what path you choose. Making sure things are well documented and clearly communicated throughout the facility is the most important thing. You don't want to end up interpreting files the wrong way. Especially ACEScg vs ACES 2065-1 can be a sneaky trap.

Report · Nov 20, 2023

great Shebbe! a lot of precious info to think about and test...

And only now I realize that I did not see the show all checkbox, I really skipped this part even if i watched the pannel many times... my bad!

it's time to meet all the other departments and establish and test some workflow thank to all these info

Thank you Shebbe!