Aces for LOG-Rec709 roundtrip in After Effects

I have been looking for a way to composite linear/srgb footage over Log footage while being able to revert to Log at the end in After Effects.

I have not found a guide to this roundtrip and am looking for a way to convert my LOG through the right color profile (let’s say Arri) to Rec709 but also revert back to log the whole composite at the end.

in all the tutorials and guides I have seen, there is no such workflow, and ACES is used only for getting better highlights and color corrections, but not a proper roundtrip back and forth.

this would be the equivalent but I hope much better workflow than using Ae’s color management with ICC profiles to go to linear conversion and back. any advice on this will be much appreciated.

here in the folder is some Arri log footage and another linear gamma footage:
https://drive.google.com/drive/folders/1P8J7bmOwK8aHKXl4CW8TgBlEs90I9-as

I want to composite the football screen on the log footage, and make some digital cleanup to the log footage and in the end need to export to colorist as log. I could work on log the whole way through, match the linear gamma footage to log, place a lut on top to see how it would look, but I much prefer to composite on linear gamma and not log. in Ae I can kinda do the roundtrip with ICC profiles, or use color profile converter, cineon converter, OCIO lut and inverse lut, but I would like to see how aces handles it :slight_smile: Please enlighten me how would that work.

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First, one assumption : the football footage has to blend with the scene and is not just to be layered on top with colours untouched. Now, to do what you want in an ACES workflow, you would use two different IDTs, one per clip. Once applied, your clips will be in the linear/AP0 colour space but you’ll usually convert them to either the ACEScc or ACEScct colour space which are log encodings of the ACEScg colour space (a.k.a. linear/AP1). You can then convert back the graded clips to linear/AP0 and either hand that to other facilities or apply an output transform on it to render to Rec.709, Rec.2020/PQ or Rec.2020/HLG.

I hope I was not too confusing :slight_smile:

EDIT: Oops. I completely missed the “for After Effects” part. Seeing as I don’t know much about how ae works, I can’t help you with applying an IDT in ae. I really wish that I could have been of more help.

Have you tried to install the OCIO plugin in AE? Should be fairly simple. You could also potentially switch back your sRGB to Lin and comp everything that way.

Cheers!

Thank you both.

@jmgilbert I am aware there needs to be additional color correction to sRGB/Rec709 assets over the LOG footage but I first want to put them in the same color space and apply conversion to them instead of pushing it manually by grading these to look like LOG. and I have installed OCIO and was able to use it but I haven’t found a guide or tutorial to show me how to got to Aces and then back to LOG non-destructively to all my assets.

from what you wrote, I see that I need to apply OCIO to these clips, but I am not sure which settings. and what to put eventually to bring it back to LOG. if could you guide me to what to do exactly in the example I provided to successfully set it up so at the end I have a LOG output altogether

@chuckyboilo yes I installed OCIO, I haven’t seen any guide about the workflow I am looking for, if you could explain how would that work - what settings should I apply to the LOG footage, what setting should I apply to each sRGB/Rec709 asset and what setting should I apply to an adj layer on top so everything will be non-destructive and I will be able to output LOG composite at the end.

Ok I had a look at the images. So first of all the important thing would be to get your terminology correct. The football image is not “linear” in the sense that you want to express here. Especially on ACEScentral. It’s a gamma encoded SRGB image. Most likely REC709?

Ok so what you want to do (if in understand correctly) would be to comp everything together and then export everything in LOGc? This is doable but the sRGB image most likely will not display properly. And, obviously this is a ACES forum so most people will push you to just not do that and work completely in ACES.

Now before I go on I need to know why you need to go back to LOGc. Is to grade? Is it going out of your hands and into the hands of another studio/colorist?

That type on integration could be easily done on a graded image. It’s not “full on compositing”.

Send me some more infos and I’ll try to work you thru this.

Thanks!

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Thanks Charles,

linear - I was looking for the right term. thank you, yes - sRGB image. please let me know anytime I am not accurate, I am here to learn.

I want to composite in linear/display referred look. and at the end return a LOGc for another studio/colorist that’s right.

so I would like to convert the LOG to some profile that my display can show the right colors, composite my sRGB assets on top of it and correct them accordingly, and at the end put some conversion on top of at so that everything will be back as LOG - and for all of that to be non-destructive to the original video signal. I am looking for the pipeline that will enable me to work this way. if I get the benefit of getting accurate composites since it’s Aces pipeline - great, but the need here is mainly to be able to export LOG at the end.

Hi @yooofi

We do a lot of screen inserts at our company and usually the footage consist of client apps or other content that has to stay somewhat color accurate. If that’s also the case for your projects I wouldn’t advise to make it log but rather keep it separated an maybe only adjust the contrast and luminance to match the overall feel of the final grade.

Now if your pipeline would require the full comp to become a single image rendered out in log in order to be final processed somewhere outside of After Effects it’s not that difficult to set up with ACES and OCIO. You would just convert the insert to the camera’s space like Arri Wide Gamut / LogC.

I’ve made a simple example showing this with a layer above it as the reference conversion lut. You could also use the ACES transform but viewing that means that whoever you hand over the log rendered footage would have to use that same output transform if you want the same visual result but I don’t know how the rest of your pipeline looks.

My example setup is without using AE color management but you could apply whatever you are used to next to this workflow.

https://drive.google.com/file/d/1F6NyVQcDPuVXv6ArlS3dBJ2qu5wLwXPA/view?usp=sharing

[edit]
I see that you will hand over the render to a colorist. You could ask if he/she works in ACES. Then you could use an aces out to sRGB or 709 depending on your monitor as the reference adjustment layer or ask the colorist for a LUT of what the look roughly is going to be so you have an idea of the final result in comp.

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@Shebbe Thanks for the project files. and you even tracked the footage :slight_smile:

this workflow is basically not really using ACES right? instead it’s using OCIO for converting the sRGB gamma footage to the background footage using a profile conversion. so I don’t really need OCIO or ACES for this workflow because I could do that with Ae’s ICC profiles natively in Ae (same as OCIO - set from rec709 to Arri) it does have popular camera profiles, maybe not as vast as ACES configuration files.
here’s a screenshot:

correct me if I am wrong, the pros in this workflow (using a plugin to convert profiles on the sRGB gamma footage) is I can skip all the color management hassle and it’s very easy and no need to readjust color of graphics and assets in linear workspace (could be an issue when you need to be super accurate) the cons are that I am not utilizing the full potential of the footage so highlights and blurs, blending modes and color corrections will be done in a less than the full potential.

after further exploring, I see that if there also an option to invert a LUT on OCIO, so that could come in handy if you don’t have the profile of the camera in any plugin configuration or maybe all you have is a specific LUT. set an invert LUT on each sRGB gamma asset… what do you think about this type of workflow?

and I did finally find how to get ACES to work for this purpose all the way. this means using ACESCG working space, 32 bit, linearize or not - depends on what’s in there. preserve RGB for each imported assets, and upon export’s disabling also in color management, and setting on each footage with OCIO from its profile to ACESCG. then on top of everything an adj layer set from AcesCG back to the Log footage camera profile. it seems I can’t post links anymore but, what you think of this type of setup?

I never really used the built in converter but it seems that it has the same options on the Arri side of things. In this particular case you wouldn’t need ACES yes. The other thing you mention doesn’t really have anything to do with using ACES or not. Compositing in linear can be done with or without an ACES workflow. If your colorist doesn’t use ACES you don’t have to either but you can still use the color transformation side of it to get your data to a common space to work in which for linear would be ACEScg. Then you could output to whatever log space you’d like and not just the ones Adobe deems important.

I also thought this approach was the way to go but I find that it’s better to work in your output format and keep using AE management alongside it because it requires less setup work and doesn’t require you to constantly change the way AE reads files.

This would be the ideal workflow if you’d use a lot of CG and you’d have to comp it with footage but if all you want to do is simple screen inserts I would never go this far and complex for such a simple comp.

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thank you for all your comments and information.

yep it is nice to be native when you need to transfer the project. especially when OCIO requires 2 installations and I can think of many user errors in that case.

do you mean the Invert LUT workflow? it’s not related to Aces but it is related to OCIO because AFAIK its the only plugin that enables reversed LUTs. BTW from what I see it didn’t break anything and the signal is the same (as long as you don’t try to roundtrip between back and forth).

I see if I don’t use ACES, I get a different fidelity of color when pushing exposures and blur and I guess other things as well. that is - just choosing Ae’s color management to linearize the workflow in rec709 workspace, linearize workflow, setting profiles for each footage to linearize the footage profile to rec709 workspace linearized vs the same thing to acescg workspace, linearize workflow and using OCIO to set profiles show different results.

it seems now I can’t post images, I wanted to show you a comparison. never mind :slight_smile: this post is getting reduced functionality day by day (because I am a new user)

as for the tutorial you posted, yes I have watched that but this is a different type of pipeline I don’t do really.

Sorry. I meant the linear workflow part.

Do you mean using ACES to go from working or camera space to display space ie. Output - rec.709 or Output - sRGB?
If that’s the case the reason being is you are using the ACES RRT designed to transform the data to the display in the best way it can matching what we as humans would expect to see which is vastly different from just applying a power function to linear data.

In your case this wouldn’t matter because you said you will deliver the content in scene-referred log to the colorist. What you’d see in the viewer with your reference transform layer would only apply if the colorist is also using ACES to get to the display or if you would deliver a final image in display space.

His video is focused on CG renders going to sRGB but the same principles in setup would apply to rec.709 too. It will give you the same result with less setup work and chance of error along the way.
But if you prefer the non display color managed ACEScg workspace approach with Preserve RGB for each element that’s also fine :slight_smile:

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Yes, this is the workflow I was describing: www[dot]youtube[dot]com/watch?v=1ixzKR21jdw&t=3s&ab_channel=JacobDanell

so do you mean this workflow is possible without ACES to produce a scene-referred output AND get to composite with higher fidelity in highlights, exposures, blurs and such?

I would REALLY love to use Ae’s CM in the pipeline I am describing, and skip all those preserve RGB ticks and all the plugin switches necessary :slight_smile: but I don’t see how that’s possible using the described workflow in the tutorial. I have tried. I would love the less amount of setup as possible.

the main issue is I want to be able to composite my sources in a convenient color space. I have different video sources and I would like all of them to play nice. the ideal way (in my head) would be to make my LOG footage convert to sRGB, then everything is composited in sRGB gamma workspace, with the option to use and adjustment layer on top to make all the composite back in LOG. and I thought I could do that - this workflow is described here: www[dot]provideocoalition[dot]com/after-effects-and-alexa-part-2/
but unfortunately I discovered this workflow does degrade my video signal (slightly but still).

so I said OK I can maybe use ACES to do that roundtrip and make them all play nice in ACESCG, and it works but it means the video is in a field where it has to be under adjustments to look properly, and pushing colors to look as I want them is a struggle, and many ticks and switches but you get the benefit of better looking effects. and there’s also the method you described which means don’t touch the LOG, convert the sRGB gamma to scene referred footage, and use a LUT on top. which is nice.

Possible but probably a lot less nice to set up given AE barely provides proper tools for this.
Compositing in linear however is not something new. ACES with the OCIO plugin just allows you to easily convert different camera or display referred images to one common domain of choice to work in and treat the equally making it easier to composite material from different sources.
Because ACEScg is a linear colorspace you can use this as the sandwich to do all your effects in but doing it in linear rec.709 or linear Arri Wide Gamut would be equal in math if I’m not mistaken.
It’s just that ACEScg (AP1 primaries, linear gamma) is the choice of workingspace for a compliant ACES workflow. ACEScc or ACEScct is a log version of this colorspace for DI / colorgrading.

You can choose rec.709 as working space without linearize checked. Using rec.709 encoded footage like that insert and Arri LogC file won’t be converted by After Effects resulting in the same behavior as Preserve RGB. You still work linearly because you are in 32-bit and ACES converts it to linear by going to ACEScg.
You can be sure with this setup that when you export, profile embedding will happen as expected and as added bonus if you were to do final composites going to display it’s easy to add graphics on top without having to struggle with the fact that the entire project is in linear ACEScg.
For anything that isn’t rec.709 you would have to check preserveRGB though otherwise it converts it to that first. Things like cg renders in .exr you would Preserve RGB.

I’ve made an example setup from that same project earlier. Maybe that helps.
Just keep in mind that we aren’t telling AE we’re working in linear so if you use Camera Lens Blur you have to uncheck Use Linear Working Space and for Exposure check Bypass Linear Light Conversion.

Not all effects benefit from working in linear. I think denoising for example is preferred in log. And not all fx in AE support 32bit. Using Lumetri is definitely ‘broken’ in linear I think as it’s controls were designed for rec709 normalized or log and a lot of other color tools probably too. Doing color adjustments in log should feel much more natural compared to what you are used to.
What does feel nice is anything blur, glow and exposure.

Lastly I’d say this is all great and I find being able to use ACES for composites in AE really cool but so far I’ve rarely used it because working in 32bit just destroys performance in AE compared to other software. If you can live without it for simple composites I’d always do it unless there really is a specific reason to use it. :slight_smile:
Maybe once we get OCIOv2 with ACES 1.3 we can run on GPU and it might be faster!

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I have noticed a different behavior but it’s just not worth the hassle it’s sooo error prone it’s insane. it’s better to leave it as rec709 linear or not and use OCIO to convert.

thank you, after days with this, this is similar to a setup I also created. I have a few questions about the project:

  1. why all the adj layers and not applying the OCIO directly on the footage?
  2. I have seen you use output as input, I think it’s not so good it creates clipping, better use generic or utility-rec079-curve I see. see the difference
    image

I also never used 32bit unless I had CG that needed that, and lately I noticed when comping and coloring log footage I also needed 32 or else I got clipping. not too much of a performance hit in my composites but I could always go to 16 and 32 interchangeably. the one thing that I almost never do is linearize working space… only when I have to when I have CG that needs multipass and was created in linear. but I am always thinking maybe I should start doing that…

Whatever works for you. I just did it so I could name the layers with what I did in case it didn’t load properly for you. It also helps a bit visually for yourself so you can see what goes in and out in more complex setups. If After Effects was node based this wouldn’t be such an issue :slight_smile:

Yes I did see the clipping but that’s expected. You aren’t supposed to use sRGB texture. That was designed for sRGB textures for light computations in CG rendering.
Because you are viewing ACEScg in linear in that comp which your display by far can’t show it looks like clipping but the data is retained. It’s just above 1.0
image

Similarly we can see the data behind the guitar is of very high brightness when if we view it in linear by turning off the lin-to-log and display conversions. (turned viewer exposure down in picture)
image
This is why compositing in linear works so well. We treat it as if we are still in the scene.

I said this but reflecting upon it I realized that for inserting a display “texture” into the scene it is preferred not to have a brightness range that is almost equal to the scene itself so it is kind of like treating it as texture. I guess you could use it or use Utility - Rec.709 - Camera for this if that gives better results.

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