[Released] Timeline tone mapping

Would love to have some Cine-EI (Sony) based controls or have it read the metadata and offset the lut by the intended exposure. I often shoot at 800 or 1000 base ISO and then it comes in over exposed in this new workflow. As it is is now it becomes hard to accurately bring down the exposure and I had to revert to my old methods.

It occured to me last night that one thing that might be misapprehended by many users of Premiere, is how the math works in Premiere. Something you may not know or consider, that is crucial.

All computations concerning image data within Premiere are performed in 32 bit float.

What does that mean? Or perhaps, what are the full implications of working within that 32-bit float math? (And this is why nearly all other color/tonal tools are in the Obsolete bin ... their math ain't good.)

For an example, let's take a numerical data range of zero to one thousand. 0-1,000. All as whole integers, no fractions.

Now 'shrink' that to a range of zero to one hundred. You lose a LOT of data, right?

Well ... no, not if you use the glories of fractional mathematics. When using a proper mathematical calculation to accomplish the change, while 500 does become 50, 499 doesn't become rounded to either 49 or probably fifty ... it becomes 49.9.

You keep every one of your individual data points, just in a smaller 'range'. There is no "lost" data.

And by so doing, you can even do all sorts of mathematical operations to the data and then mathematically expand back to a range of 0-1,000 ... with all computations working out exactly as if you'd stayed in the wider range to begin with.

So when is the data lost?

Only when having to return to a 'whole integer' type of math. Which in this case, using a Rec.709 timeline, means going to the monitor display, properly set to 100 nits, and when exporting a 'new' file.

While working the image data on the timeline through the Lumetri color controls, you are working with the fractional math. Not the after-export 'whole integer' data.

So the changes are computer as applied to the full data, simply ... mathematically ... using a smaller outside range. For both dynamic range and color.

And yes, the various mathematical models that can be used will 'look' a bit different. For example, in Resolve, you can apply transforms from a wide gamut to Rec.709 through various processes, transforms, LUTs, etc. ... and all of them will get all your data through.

However, they do not exactly look the same. Which is why colorists will have their preferences for how to do the math based on which feels easier for them to work the controls upon. Are any "wrong"? No ... not if they are built properly to keep all the data. They just use different methods in the scaling of the data. Which results in a different 'look' to the displayed image.

In Premiere, you can apply a correctly built transform LUT in the Interpret Footage Input LUT slot, and a LUT for the same purpose from a camera manufacturer, and get a slightly to notably different look to the image. But both still have all the data included due to the calculations being in 32-bit float.

Or use the transforms that the Premiere color devs have built, and get another slightly different look, but again ... with all the original data as part of the calculations.

And when you then work the Lumetri controls on the data, it still works with the original data. Not with truncated "whole integer" data.

The program must compute the results of that work out to 'whole integer' math to send to the monitor, of course. And for exporting to an SDR/Rec.709 file.

But the calculations for the transforms, however applied, and for all work done within Lumetri, are done with 32-bit float 'referencing' the original data.

Can we get an option for display colour management (quicktime version) instead of using compensation luts? And instead of crushing all the shadow detail only to add a compensation lut so it matches the crushed version on export..

Whats the workflow for those of us that select a bunch of media and then click the "create new sequence from media"?  Will there be an option to use HLG media, and have it create a time line that can be converted to 709? for exporting?

I tried to read the notes above several times to follow along and It seems the current workflow is to create a timeline that is already Rec709, drag your clips to it, an it will then auto tone map...

I am hoping for a way to create a complaint REC709 timeline with HLG clips by using the create new seq from clips process as this saves me a the hassell of pickign resalutiosn etc in many cases.

I cant download and use the beta or I would check for this myself, I hope someone who has already used it can confirm.

Second question which is not clear,  can you create both a HLG and REC 709 export that is compliant and not blown out with this process?  basicaly built the project once, and export once (or twice) but get a REC 709 and a HLG project fromt he same timeline thats proper?

Baffy,

You don't like ... messy. And I'm sorry, but this world, by nature, is very, very messy. Color isn't any different.

The colorists I work with, teach, and learn from all stress that there is The Ideal ... and then there's what's possible and/or sensible with this particular project. Which frequently has nothing to do with The Ideal.

Is that frustrating? Yes.

The reality is, there are many ways color management and correction can be handled. And the viewer will never be able to have clue one about how it was done if done carefully and thoughtfully.

So that's why I answered as I did. Do I agree that The Ideal is a wide-gamut working space, with transform for monitoring? Yep. Stated so very clearly in fact.

Is that absolutely necessary to have good color results? No, not at all.

Which is why I pointed out that for many years, nearly all pro colorist work was transformed on input to Rec.709. There weren't the wider spaces to begin with. Does the material look good still? Yes, of course.

So ... where does maintaing a wide gamut working space during color work become really useful?

That's easy ... when you really, really have to push the media hard. As for an extreme grade, or because the DP didn't get their work done well and the exposure/contrast whatever is way, way off.

And the other thing that helps with this being messy ... in so many projects these days there are drones, DSLR and other rigs shooting H.264/5 formats. That even when they are supposedly "10 bit" ... have shall we say, amazingly thin bits?

You can't match those "up" to the better cam's media, so ... the colorist often has to bring the better stuff down mostly to the lesser stuff to get a good, visually consistent match.

And so there are projects my colorist folk work even now that are on a Rec.709 timeline, because there's mostly 8-bit media, or a significant proportion of 8-bit, and no reason to work wide gamut.

Can you spot those when on your TV? I highly doubt it.

But let's say we want the Ideal of the wide gamut ... there's still a ton of very different ways to approach that. There isn't one "perfect" way.

Working in ACES is supposedly the Ideal, right? Well, that involves a transform of all media into the ACES working space/s. You've left the original behind on input anyway. And a lot of colorists don't like working in ACES because you end up with a ... not really "look" per se, but the feel of an ACES image.

Nearly all colorists I know that work with wide-gamut working spaces transform ALL clips to their favorite flavor of wide-gamut. In fact, I can't think of any that actually work all clips in their own native space. So every clip on their projects goes through a transform pre-grading.

And in fact, to them that is the whole point. They make it all the same gamut.

And every flipping one of them handles even that process differently. Some do it all in their Project and Media Pool settings. Some do partly there, partly in the nodes of their grades. And some do all their color management in the nodes.

And as I noted, frequently they will shift color space/gamut in a node to X, then back to Y in the next node, because a certain tool works better or smoother to their taste in X rather than their normal space of Y.

I've seen power grades that have up to six gamut transforms in the grade. That may or may not be used on any clip in the entire project.

What it gets back to is that it is important to handle color transforms cleanly and well. If done so, then where and how you apply them is ... totally negotiable.

And to the viewer, normally completely irrelevant.

So that is the reality of color for grading at this time. But most of the above wide gamut stuff really only applies when you are pushing the media hard for some reason. All my colorist acquaintances will say a properly shot project can be worked in a Rec.709 timeline without any notable problems. They've done that many times.

So the one's I've talked with would prefer Premiere had a wide gamut working space, just like thee & me. However ... do they have a HUGE problem with the Rec.709 workflow? No. With the proviso you get decent media, no viewer will ever know.

And ... HDR is still the Wild Wild West. With all the gambling and suprises that come with that at this time. Very few people working in Premiere will have monitors really up to the task of grading HDR. Making it look mostly ok, sure.

But in reality, for most editors, for the vast majority of uses, "mostly ok" is all that is needed. Realistically. Your viewers will be on so many different screens and viewing environments they simply can't really see what you've done "properly" anyway.

Neil

This is a complex and fascinating process to study.

Input LUT slot usage

From what I've learned, the Interpret Footage Input LUT slot is well used if you wish to apply your own control to the transform of any wide-gamut media to Rec.709. Adobe chief color scientist Lars Borg suggests using LUT Calc to create transform LUTs for either/both dynamic and color space/range changes. From my testing so far, that seems to work.

And so for say some log or RAW media that you have, if you create a basic transformation LUT you can apply that in the Input LUT slot, and use the Override-To option to set the color range of the result to Rec.709.

Doing it this way, you could skip their tonemapping and apply whatever normalization you prefer. Or of course, you can use their tonemapping, which at times can be quite useful.

Override-To Option functionality

That Override-To option actually doesn't apply anything to the media. What it does is tell Premiere essentially which NCLC tags to use to mathematically "see" the image data when it uses it on a sequence within that project. Totally a metadata operation.

So if you have an HLG or PQ clip, and use the Input LUT slot to transform that to fit within the Rec.709 sequence, you must also tell Premiere to use the "stock" NCLC tags for Rec.709 when working with that clip. By setting this Override-To option to Rec.709.

@eric escobar 

Color space conversion is a very necessary and important process when working with a material. And here it is very important that the color space is interpreted correctly without using LUT. This is extremely important, I stress, extremely important. Colorists have been waiting for this for a long time. Otherwise, we will get a cropped dynamic range without the possibility of recovery during subsequent work with color. A practical example: you have intreated the material into the color space using LUT and passed it to the colorist for improvement, who in turn will not be able to manipulate the flexibility of the material, since LUT transform the color space and thereby trim the dynamic range.

Therefore, it is necessary to take this into account.

This will be helpful.

Thank you