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Szymon25184305sowk
Participant
July 2, 2025
Question

Up-mapping from SDR to HDR - differences in Rec2020 and Rec2100 - how to achieve a full range?

  • July 2, 2025
  • 1 reply
  • 1076 views

Hi,

Question to experts. 

I'm getting clips to be played out of the UHD HDR OB van. It works in HDR. 

The clips are converted form SDR versions. 

On the editing suite they look ok, but in the OB they are dimmed. 

Please have a look at three screen shots. Lumetri Scopes for Rec709 (of course SDR clip on the timeline), Rec 2020 and Rec2100. 
Rec2100 simply shows lack of full dynamic range. 

Now - if you look at the fourth screen shot - showing test bars from the OB you can see full dynamic range in Lumetri Scopes in Rec 2100.

BUT - this dynamic looks overexposed on my Canon DP3120. See picture. 
Lowering the exposure -1,2 makes the histogram correct on the monitor (picutre) BUT it is too low on the Lumetri Scopes in Premiere (getting to the range of Rec.2020)

 

So bit confused here..
How to up-mapp SDR footage to achive full scale in Rec.2100?

Rasing Exposure, Whites, Highlights of course makes the whites goes up but the whole picutre is getting too bright.. Am I missing something? 

 

Thanks

1 reply

R Neil Haugen
R Neil Haugen
Legend
July 2, 2025

Getting proper color management takes a whole series of correct settings, and seeing only a few limits me to guessing. Note, HDR is still the Wild Wild West of video. I work for/with/teach pro colorists. The majority of pro colorists have as of July 1 2025 never delivered a single paid HDR job. That will be changing over time, but far more slowly than we expected six years ago.

 

That said ...

 

First, you're right that Exposure is not the tool to use, as it will lift way too many values "up".

 

Second, use the CM to manage the space ... auto detect log, auto tonemapping on, override color space, and there are tonemapping options in several of the CM twirl-down sections. Any expansion of the data via their tonemapping algorithms is almost always preferable to manual changes.

 

Next, for doing HDR color corrections, it's probably more useful to set the scopes to 10 bit, and the scope color space to HLG. After grading, you can set scopes to HLG and then check the nits levels on the left, but probably don't grade with the HLG scale, as it's a completely "curved" thing. Over two thirds of your usable brightness will be in the bottom quarter of the scopes, way too compressed, as it insists on showing a log scale clear to 10,00 nits. 

 

Next, your OS, and your monitor, must be capable of HDR ... and for monitors, well, most even that say they can do HDR do not do it correctly or even usefully so for editing/grading. Might not be too bad for playback of somebody else's HLG, because ... you don't have any idea what their original intent is, so you won't know if it's off will you?

 

There really isn't a monitor under $1,000 that handles this sorta kinda usefully for color/tonal HDR work, and really, the new Asus PA 32 UCDM (I think that's the full listing) is probably by far the best thing under 3 grand. And yea, that's frustrating.

Everyone's mileage always varies ...
S
Szymon25184305sowkAuthor
Participant
July 2, 2025

Thank you R Neil Haugen,

Well - I've been working with HDR for few years now and have some understanding of requirements and limitations. I am, however, video engineer so I can setup HDR environment, monitor signals, control the conversions and .. validate footage I'm getting however when it comes to details with footage creation - especially graphics - like in this case - it is a different story and to my surprise I got confused checking clips I got. 

In my opinion the major problem with HDR is that people think that conversion will do the magic and they prepare SDR versions only, converting them at the end and expecting great result. But that is no wonder as many of top production companies recommend such approach when it comes to graphics for live productions. 

 

As I am NOT colorist and should only accept or not the clips I got, I don't have deeper knowledge of the process how they were created but my guessing was right and the company responsible for preparation admited they just up-mapp the SDR versions. When I showed them that in Rec.2100 white is at 75% (roughly) they said they have no idea what they should do with it. 

 

Comming back to details you have mentioned: scopes were/are set to 10 bit, color space was HLG. You can see it on one of the pictures I've included. I'm not checking on my computer monitor of course - I use Canon DP3120 reference monitor. 

I have twiked (if I can use such expression) highlights, shadows, whites and luma curve and achived satisfactory result.

BUT was couries to hear what workflow is recommended for HLG masters delivery. You say one should not grade with the HLG scale? It seems like grading without it makes the whole picutre/graphics too compressed and that is why in the Rec.2100 space there is a huge head room after transfer.. Am I wrong? 

Thanks for the input. 

 

R Neil Haugen
R Neil Haugen
Legend
July 2, 2025

Well, hello there!  😉

 

Around "here", there's not a lot of experience with HDR, so one doesn't expect a lot of knowledge ... you have more what I'd expect on the BlackMagic forums ... very nice to hear!

 

HDR is so mis-conceived nearly across the board, and Steve Yedlin had a recent hour-plus presentation on his thoughts you can find on YouTube, and although some of my colorist buds have differences with him on some things, they do think in general his comments make much sense.

 

Among other things, he would vastly prefer that we thought of dynamic range as not one or the other,  just ... a variable range. With everything always seen as a percentage of max. And then any device would simply set the 'max' at the device's max brightness, and all other values would be in their appropriate relative place.

 

I think that would actually be far simpler ... and it is really one of the best ways to approach grading HDR. A colorist bud notes he's got a few issues with Yedlin's comments ... but then adds, as a practical thing, that he grades HDR pretty much as Yedlin suggests to just grade media ... forgetting "the silliness of nomenclature".

 

He grades with a full panel, and on a nice new Flanders HDR monitor ... and realistically, when grading, he's watching his scopes monitor primarily noted both waveform and RGB parade ... and it sounds like in just 10 bit mode. Now, he has Resolve set for what his max brightness is expected to be, depending on the deliverable specs, somewhere between 600 and 2,000 nits.

 

Realistically, 1,000 nits is practically the top you probably will ever need. And it's only for reflections off glass surfaces or water, or direct bright light sources. For anything with detail in it, that is going to be 200 nits max. Which is why the practical suggestion is the "graphics white" at 203 nits. It's just above where the brightest things with details will be.

 

Now for your setup, most "newish" cameras when recording log record plenty of DR to cover up to 200 nits or more. Whether it was "recorded" as HDR or not. But note, that's only about double the range we deal with in SDR/Rec.709 stuff. So realistically you are only going from maxing at 100 nits to maxing at 200 nits, with "overhead" allowed for ultra-bright reflections.

 

Even some 19 bit Rec.709 color space media can be stretched to cover the 200 nits max normal brightness perfectly acceptably.

 

So you are not going to be grading expecting to see much content above 200 nits ... period.

 

The biggest gain in HDR work, for many colorists, is fine control, details, and subtlety ... in the shadows!

 

Grading with the scopes in HLG but using a 10 bit scale doesn't restrict the top values any more than using the HLG scale for the scopes does. That only affects the scale used to denote the specific points, not the range black to white. You are not grading in SDR when doing this. Your space is the HLG setting. 

 

You do get a lot wider view of what you're doing in 10 bit scale rather than their current HDR scale. Because they insist that the thing is set up in essentially a log format. Look at the scopes in HDR scale ... remember, your top normal value will be 200 nits?

 

Where is 200 nits on the scopes when in HDR scale mode? Well below half, right? You are never going to have anything above 1,000 nits ... so the top of the scopes scale is completely wasted space. 

 

You only use really the bottom third of the scope ... and so you cannot see details in what you're doing. Hence using the 10 bit scale.

 

Now, at this time in Premiere, "graphics" is a bit of a problem. They can oft be 'gray' in HDR or even SDR timelines. If you have an issue with a graphic showing grayish rather than white for white letters ... select the graphic clip on the timeline, then in the CM Settings, set the override-to option to HLG, or maybe the Arri wide log. 

 

Does that help explain my suggestions a bit?

Everyone's mileage always varies ...
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