Colour/Gamma Shift Bug

[Nick2049]

I have discovered that when exporting from AE to ME using H.264 my final output colours/gamma doesnt match my AE viewport.

However, if I export to DNxHD directly from AE then the colours match. What's strange is that if I then take this DNxHD and convert it (with the exact same settings) using ME, it also correctly matches!

So why the shift when going straight to ME from AE?

Results attached

[R Neil Haugen]

From your results, you'll be good to go using the HDTV/Rec.709 in Ae and without CM. And the apps will auto-magically treat the sRGB and Rec.709 stuff properly on ingesting/utiizing, so that's not a worry either.

Neil

[Nick2049]

Hi Neil,

The only issue there is, yes my export will match my AE viewport, but as you can see my sRGB source files now have the shift visible in AE, they dont match the source.

[Nick2049]

Also just discovered another curve ball Neil.

If I set my working space to none, my sRGB assets don't shift in the AE viewport, and there is no shift when I send out of AE to ME (H.264). Everything matches up, now I'm even more confused, shouldnt there be a shift somewhere to Rec709 as shown in the previous examples?

[R Neil Haugen]

"Don't overthink" is something my colorist buds are always telling their clients. Set up correctly and get to work, essentially.

So when it works, work. Confusing as it all is. I've been through I really don't know how many hours of presentations and discussions on CM. Done it on my own machines hours at a time for years. And it's still freaking a mess.

Neil

[Nick2049]

But this is what I am trying to do,
I am trying to set it up correctly, but which method is correct? The results are so varied and this wasn’t even an issue in previous versions.

Why does ‘no working space’ respect sRGB and seemingly automatically accurately convert this to Rec709 when sent to ME, but when specifying a working space (either sRGB or Rec709) it does not!?

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[R Neil Haugen]

If in testing on your system, no CM in Ae works and matches all other sources ... then use it.

The differences one system to another have so many freaking variables. It takes colorists highly experienced with years of doing this at times days to sort out what happened when suddenly some of their CM ain't working right. Once something works, it ... works. Use it.

And when a colorist with a $5,000 spectroradiometer, a $12,000 spectro, a $5,500 Flanders FSI monitor for SDR and a $32,000 Flanders for HDR, running Colourspace or Lightspace or Calman pro calibration software who is also fully DolbyVision certified and does the training for DolbyVision company  tells me "You're fine, just go with it" ... I learned to just go with it when it all works through the system.

In years past I had a pro portrait studio, we were so dang picky the pro labs that only did pro portrait work kept dis-inviting us to use their services as we returned too many prints for color/tonal/black-levels issues. So we set up our own lab as an additional business entity providing high-end color printing to our own facility and other studios. I set up all the spendy calibration gear and trained all the employees.

And especially at the beginning, I'd tell them just ... do what you're told. Don't even try to understand because most of the color corrections and even processor trims are so freaking counter-intuitive you wouldn't believe me if I told you.

They'd still want to contest things. Naw ... just do what you're told. And after a few weeks, they'd finally say ... you know, none of this works like I thought it would. Would you please tell me what the hay is actually going on here?

And at that point, they could start the process to learn how color print corrections and processor control trims actually worked. It still took years to get good and fast for most people.

I shared this with a group of colorists at NAB ... and they all went ... wow, that's us talking with new employees and clients! Ha.

Neil

[Nick2049]

Hi Neil,

I understand this is a complex topic with many moving parts. But I don't feel like it's asking much to have a basic workflow (on the same workstation, using the same monitor) which involves your source assets, AE viewport and final export all match up in terms of colour/gamma.

'Would you please tell me what the hay is actually going on here?'

But this is exactly where I am at now.. Why is it functioning this way? Why does no CM seem to respect sRGB and automatically convert it to REC709 on export resulting in an accurate representation of source assets? Why does having an sRGB working space break this? Why wasnt this the case on previous versions of AE/ME?

We started this conversation by you telling me my workflow should be REC709 if my output is H.264.. now we are saying disable CM altogether?

I also tested this on two other workstations with the same version of AE and ME.. exactly the same results.

So far it would appear that with the latest version of AE and ME, the only way to have a final H.264 output that matches your source and AE viewport is either

A - disable CM, have no working space, export via ME straight from AE

or

B - have an sRGB working space, export first to DNxHD from AE and then convert to H.264 in ME

Can anyone from Adobe chime in here please?

Thanks

[R Neil Haugen]

The controls don't necessarily do what you think they are. Turning on/off the display color management in PrPro for example ... it doesn't mean there's no color management, not even close.

What that means is that Premiere will assume your monitor is correctly set for a Rec.709 workflow and perform alll steps accordingly. Premiere is hard-coded to work assuming a tightly controlled Rec.709 setup and standards. Period.

So actually ... if your system is fully rigged for Rec.709, you are better with the display color management option of PrPro turned off. And this is confusing for probably the vast majority of users, and I don't blame them for being confused.

The display color management option means Premiere will look at the monitor's ICC profile, and attempt to remap the image to a proper Rec.709 view within that profile. Not an ideal thing, but better than nothing.

But it sounds like if you turn it off, there's no color management controls "on". Which is actually, wrong.

That Premiere is so tightly coded throughout for Rec.709 has been the biggest problem in getting it recoded to work with HDR media.

Ae's CM process is very different, a lot of Ae users struggle with it. So trying to puzzle out how to match to PrPro is a pain. And again, the controls don't often do exactly what we'd expect.

On my system, with heavily calibrated and profiled monitors, I need PrPro's display CM option off for accurate work. And always use the HDTV-Rec.709 option in Ae. Unfortunately, almost everyone's mileage will vary on these things.

Neil

[Nick2049]

I don't mean to sound rude Neil but why are you adding PrPro into the equation? I am not usine Premiere at all. I am using AE and that's it.

If working space is set to none in AE then what does it assume? sRGB? REC709?

[R Neil Haugen]

It helps to triangulate what's going on between apps. That's why I brought in PrPro. It gives confirmation. If you're getting identical results in all three, you're set properly. And why is that useful? Because then anything else will see it properly also.

From my understanding, if you don't set something in Ae ... and there's nothing showing in the CM panel for Ae ... then it only works with images in their original space. So an sRGB image would be 'left' in sRGB.

And although "the web" is sRGB, that's just a definition of the color primaries. Video uses the sRGB primaries but also has other standards like a specific gamma. Which is why one needs to know what the video standards are.

Neil

[Nick2049]

Hi Neil,

When AE is set to no working space, my 'assume working gamma:' is set to 2.4 REC709.

I beleive sRGB is 2.2? So this makes sense why there is a shift, but I don't understand why it is happening here, this doesnt add up..

Take a look at the attached, as you can see, no working space with assume 2.4, results in an H.264 that matches my original source content in PS. Great, this is what I want, but why is this happening? If it is assuming 2.4 then why dont I see the gamma shift in my AE viewport? and also even if it is displaying correctly as sRGB 2.2, why doesnt the shift occur when it ends up as REC709 2.4 in ME?

What do you make of this?

Cheers

[R Neil Haugen]

As little as possible ... and I'm not being sarcastic or anything. Much of the interactions in CM don't seem to make sense. You can sit down with an engineer and get an explanation that seems to "handle" something, walk away ... and 20 minutes later have trouble remembering which particular variuos rabbit holes were used to patch an answer together.

So what I've been through with so many colorists ... and on the Slack channels and online forums I'm on every day, this is always a current discussion ... the basic answer always gets back to reality.

"This is the basic standards. This is how to test if your system is working correctly. Once you have that, no matter what the logic of the settings seems to imply, just get back to work."

And this same discussion will happen no matter the apps and the gear. From PrPro through Resolve, Avid, Baselight, Nuke, Ae, Fusion, whatever. Macs/PCs ... everything.

And how people need to set similar gear to get correct results can seem rather puzzling. But again, once you can verify the results, well ... there's work to be done.

Do I like that answer? Hades no. I like nice, neat tidy solutions. That's where an autistic brain that lives totally by anlysis/synthesis wants to be all the time. Nice, neat, tidy solutions. Which has some of my buds simply roll their eyes when we're together at NAB or MAX.

As I was told a while back by a guy pretty much an amazing expert in all this  ... "Ain't happening in this lifetime, bro ... get a Life ... "

Neil