Shooting for HDR

https://nofilmschool.com/the-great-john-brawley

If you’re interested in shooting in HDR, you might find this approach by the great John Brawley fascinating. I’ve been enjoying the freedoms of grading in HDR and P3 and pleased with what’s possible. Don’t forget though if your work is being shown on television, you will need to adjust for those deliverables.

Yes, the UHD Alliance specifies Rec. 2020 colorspace for consumer television. P3 is for theatrical release, i.e. projectors. Resolve Studio has tools in both RCM and ACES for the appropriate color space transforms. YouTube also supports HDR10+(Plus).

YouTube states in their HDR UPLOADS help topic the following:

"If you're grading your video, grade in Rec. 2020 with PQ or HLG. Using a different configuration, including DCI P3, will produce incorrect results."

and

"In cinema, it's common to master HDR videos in the DCI P3 color space, with either the DCI (~D50) or D65 white points. Doing so is not a supported format for delivery to consumer electronics. When mastering, choose Rec. 2020 color primaries (the Rec. 2100 standard implies Rec. 2020 color in many apps).
A common mistake is to master in P3, then tag the result using Rec. 2020 primaries. Doing so will result in an oversaturated look with shifted hues."

Thank you, Tom. This helps understand the best approach for different targets.
One issue I have is that I’m using the Apple Pro Display XDR and it defines a reference mode “HDR Video (P3-ST 2084)” as well as a few other P3, Rec709, Rec601.

So I’m working with what I can see on the display. Resolve has Rec2021 ST2084 and I’ve used that but not sure I’m doing this correctly. I can define Input as Rec2020 in Resolve though.

If you’d like to provide more details on the correct settings, I’d be interested in trying those too.

What happened was that Dolby Vision and HDR10 were in the wild before the UHD Alliance had released their spec for UHD Premium; Dolby Vision cinema was already at AMC theaters, of which there were only 3 or 4 before they became mainstream. HDR10 even before it had that name was just a subset of Dolby Vision, did not include the full feature set, did not share dynamic scene by scene tone mapping (ST.2094), but sharing the EOTF known as PQ, and adopted as ST.2084 by SMPTE. If you google any of those terms, or just HDR there is wealth of information now. In the beginning we were navigating in the dark, so you'll find a lot of content with incorrect transfers or garish neon-like colors, and equal number of complaints of being too dark or too light. The tools are much better now, Resolve Studio with supporting Decklink card, (Decklink Mini-Monitor 4K is only $195) allows you to see HDR as you are grading it, either on a professional monitor like the Sony BVM300, or on a consumer UHD that supports HDMI 2.0a or higher, which is almost all of them now.

But the most important point in considering P3 for your deliverables, is that P3 is not a supported color space in h.265 (HEVC), the most common HDR supported format. When I say not supported, meaning you don't have the option to choose it because it's not a part of the h.265 VUI instruction set.

P3 is a smaller subset of the 2020 color space, so the reasons for using it are that your target is a P3 projector in which case the deliverable is not going to be HEVC anyway, or you are grading on a monitor with a P3 colorspace.

If so, there is still a way. As mentioned, Resolve Studio supports ACES and RCM, both have tools for supporting the P3 subset within the larger 2020 colorspace. In doing so, you can then properly output and tag the video as Rec.2020. The P3 primaries will be a subset, meaning the RGB primaries endpoints won't reach to the full extents of Rec.2020 primaries, but that's exactly as it should remain, a self contained subset of 2020. You can have your cake and eat it too!

Thanks, again. I’m normally using h.264 for output. Is P3 colour space available there?

I’ll look into this further but it’s easy to find things that I wouldn’t recognize as incorrect. Unfortunately the inexpensive cards I could put in the Mac Pro aren’t any help to me as the Pro Display XDR only takes a Thunderbolt 3 input. I’d have to buy another monitor… I know something I should do one day, but I was hoping I could manage with the Pro Display XDR.

That was a lot of information to absorb, but it can be summarized this way, HDR itself supports P3, 701, 601 etc., but HDR10, which is the naming convention given by the UHD Alliance for UHD Premium specifies 2020. So if you want compatibility for the largest audience then you want those smaller color spaces to be self contained subsets of 2020.

H.264 (I think) does support P3 color but does not support ST.2086 HDR static metadata. That means it won't have the metadata to enable HDMI2.0a to switch the television into its HDR mode.

You can still use it, but you will have to wrap it inside a Matroska (.mkv) container that permits inserting the HDR (ST.2086) metadata after the h.264 encode has been completed. The h.264 won't have HDR repeat headers, so it's a bit of a hack but it works (For YouTube).

Unfortunately the inexpensive cards I could put in the Mac Pro aren’t any help to me as the Pro Display XDR only takes a Thunderbolt 3 input. I’d have to buy another monitor… I know something I should do one day, but I was hoping I could manage with the Pro Display XDR.

You need a 2nd monitor anyway to use the decklink card. The decklink card will be used to display full screen output in HDR mode, the thunderbolt monitor for the Resolve GUI in SDR.

If so, there is still a way. As mentioned, Resolve Studio supports ACES and RCM, both have tools for supporting the P3 subset within the larger 2020 colorspace. In doing so, you can then properly output and tag the video as Rec.2020. The P3 primaries will be a subset, meaning the RGB primaries endpoints won't reach to the full extents of Rec.2020 primaries, but that's exactly as it should remain, a self contained subset of 2020. You can have your cake and eat it too!

All great information Tom. The only thing that should be added is that Netflix is an outlier by requiring deliverables to be ST2084 but P3 D65 — not even the P3 limited inside REC2020 colorspace, but straight up P3 D65.
https://partnerhelp.netflixstudios.com/hc/en-us/articles/360002088888-Color-Managed-Workflow-in-Resolve-ACES-

I don't know whether Amazon and Apple TV follow that standard or stick with REC2020. Apple TV seems to be particularly all over the place as some of their series jump between plain HDR10 and Dolby Vision episode to episode. Perhaps that was a metadata glitch with their stream, I never could confirm why it was happening.

Thanks, again. I’m normally using h.264 for output. Is P3 colour space available there?

I’ll look into this further but it’s easy to find things that I wouldn’t recognize as incorrect. Unfortunately the inexpensive cards I could put in the Mac Pro aren’t any help to me as the Pro Display XDR only takes a Thunderbolt 3 input. I’d have to buy another monitor… I know something I should do one day, but I was hoping I could manage with the Pro Display XDR.

Rec2100 ST2084 for the timeline and "use Mac display profile for viewers" with the Pro Display XDR P3-ST 2084 reference mode should be the right setting to elude buying a 2nd monitor.

The only thing that should be added is that Netflix is an outlier by requiring deliverables to be ST2084 but P3 D65 — not even the P3 limited inside REC2020 colorspace, but straight up P3 D65.
https://partnerhelp.netflixstudios.com/hc/en-us/articles/360002088888-Color-Managed-Workflow-in-Resolve-ACES-

I don't know whether Amazon and Apple TV follow that standard or stick with REC2020. Apple TV seems to be particularly all over the place as some of their series jump between plain HDR10 and Dolby Vision episode to episode. Perhaps that was a metadata glitch with their stream, I never could confirm why it was happening.

Hi Jamie,
That's good information too. Thanks for the link.

We have to look at this two ways:
1.) What Netflix accepts for deliverables.
2.) What Netflix streams to its customers.

With respect to #2, what Netflix streams to its customers; can be narrowed to include UHDTV and UHD Premium certified TVs, UHD Blu-ray players, Chromecast Ultra, Amazon firestick and Roku, but not include cell phones, ipads, and tablets. So while there may app based exceptions to the rule for certain devices, if streaming is connected through HDMI with HDCP 2.2 it's got to comply with 2020 or 709 for the colorspace, or if undefined (or unrecognized as in the case of P3), then 709 will be the default color space.

From this we can see that with respect to #1, what Netflix accepts; undergoes finalizing before it is streamed.

Rec2100 ST2084 for the timeline and "use Mac display profile for viewers" with the Pro Display XDR P3-ST 2084 reference mode should be the right setting to elude buying a 2nd monitor.

Thanks Ryan,
Rec.2100 is ST.2084 or HLG with 2020 gamut.

Thanks for the reassurance on Rec.2100 ST 2084 and Rec. 2020. Since the Pro Display XDR restricts its reference mode to P3 within that, I just need to know what other gamut/gamma settings in my Project Settings / Colour Management or Colour Transforms should be? I’ve been using P3 as the gamut of the Project Settings / Timeline for mastering.

Thanks for the reassurance on Rec.2100 ST 2084 and Rec. 2020. Since the Pro Display XDR restricts its reference mode to P3 within that, I just need to know what other gamut/gamma settings in my Project Settings / Colour Management or Colour Transforms should be? I’ve been using P3 as the gamut of the Project Settings / Timeline for mastering.

Do you also use Final Cut Pro, the Apple HDR in Final Cut Pro white paper is a good read to get an Apple centric explanation: https://www.apple.com/final-cut-pro/doc ... eColor.pdf I did a few Final Cut Pro HDR exports before trying it out in Resolve, then I'll check the file in HDR on an hdtv, then SDR on my older iMac and newer iPhone.

In Final Cut, once you select "wide gamut HDR" for the library, it simplifies color space to HDR - 2020 HLG or 2020 PQ, it should be fine to monitor with P3 ST2084. You can then export ProRes to PQ or HLG, where HLG is cross-compatible with HDR and SDR displays.

ACES has "REC 2020 HLG (1000 nits) P3 D65 Limited" for output transform, would this be a good option to try to get HDR/SDR together to view across apple devices? like iMac Pro / Pro Display and P3 iPads / iPhones?

Rick,
You mentioned h.264 earlier. Are you trying to create an HDR playable file? If so, what device are you intending to play back the file on?

Curious question since John Brawley was mentioned and just interview was shared; is The Great available to watch in HDR? I get 4K through Hulu, but no indication it’s HDR. Maybe because my TV is HDR10 and they only did it in Dolby Vision?

Finally watching The Great. Perfect show to binge on a day of rest after traveling and before beginning post production on what I shot last week.


Sent from my iPhone using Tapatalk

Tim. I’m sure The Great was prepared for various versions of HDR. But John would be best person to comment on how Hulu is delivering this if people have HDR10 televisions.

Rick,
You mentioned h.264 earlier. Are you trying to create an HDR playable file? If so, what device are you intending to play back the file on?

Tom. I am trying to create my master in the best form of HDR that I can see on the Pro Display XDR which appears to be P3 gamut Rec.2100 ST 2084 (which you mentioned is a form of Rec.2020 that I can limit to the P3 gamut. I can see the difference in the Resolve / Colour tab / CIE Chromaticity display that can display the boundaries for P3 and Rec.2020.

I do not have a television capable of playing HDR (at least I don’t think my Samsung from 2009 does that, but I’ll check). So my thinking do the grade to play on my Pro Display XDR and save that for displaying later when we get a 4K television. Maybe by the time that happens there will be a true 4K DCI (P3 4096x2160) option on a television, but for now it would letterbox on the UHDTVs. Wanting to do it right nonetheless so if and when either of my narrative projects take off, I’ll know what to do.

Rick,
You mentioned h.264 earlier. Are you trying to create an HDR playable file? If so, what device are you intending to play back the file on?

It was also earlier mentioned that you cannot use h.264 if you want to encode an HDR profile that YouTube can normally play. Clicking on "Use HDR metadata" and "Embed HDR metadata" will trick you into thinking you can do something useful with h.264; you cannot. You need to use h.265 and Main10.

Yes there is a way to use some 3rd party tools to munge an h.264 output into something that YouTube will allow as HDR, but that's fragile. And with the latest updates and GPUs, h.265 can encode faster than realtime, rather than 10x slower than realtime.

Do you also use Final Cut Pro, the Apple HDR in Final Cut Pro white paper is a good read to get an Apple centric explanation: https://www.apple.com/final-cut-pro/doc ... eColor.pdf I did a few Final Cut Pro HDR exports before trying it out in Resolve, then I'll check the file in HDR on an hdtv, then SDR on my older iMac and newer iPhone.

Using Resolve without any other editor. I love White Papers as they are often very informative and not coloured by marketing copywriters’ distortions of reality.

In Final Cut, once you select "wide gamut HDR" for the library, it simplifies color space to HDR - 2020 HLG or 2020 PQ, it should be fine to monitor with P3 ST2084. You can then export ProRes to PQ or HLG, where HLG is cross-compatible with HDR and SDR displays.

it would then appear I should at least try HLG as my SDR HDTV could play it then! I was thinking PQ before you reminded me of the cross-compatibility feature.

ACES has "REC 2020 HLG (1000 nits) P3 D65 Limited" for output transform, would this be a good option to try to get HDR/SDR together to view across apple devices? like iMac Pro / Pro Display and P3 iPads / iPhones?

Yes, I was using ACES successfully and doing 1000 and 4000 nits; 1000 may suffice for output. Thanks, Ryan.

Michael, thank you very much for the remarks regarding limitations of h.264 and HDR. I shall use HEVC after all then and on the Mac Pro it does run efficiently and very quickly compared to h.264 as my own tests revealed a significant increase in fps and decrease in deliverable sizes.

Rick, I found this: https://www.androidauthority.com/hulu-4k-1023683/

Hulu’s TV shows do not currently support either one of the two main competing HDR standards (HDR10 and Dolby Vision). Therefore, the limited amount of that content is streamed at Standard Dynamic Range (SDR).

That's the most current article on the subject matter. Although, there are other sources that are older that back it up. Like this article here: https://www.digitaltrends.com/home-thea ... k-on-hulu/

So, in conclusion it seems Hulu doesn't support HDR yet. Only 4K. Netflix, AppleTV Plus, Amazon Prime, and Disney+ are the streamers I'm most aware of doing 4K HDR content. It's a bit of a bummer.

Again, this is why in the past I've said I don't see a need for 8K when we're not even fully putting out 4K HDR content everywhere. My view on wanting a UMP 12K is completely from the standpoint of curiosity about the new sensor and what it means. 12K is fine for oversampling for 8K, but again why should be be pushing 8K when 4K has still not been widely adopted?

FandangoNow has a pretty decent HDR collection. I purchased 1917, Ford vs Ferrari, The Invisible Man, still have 6 hrs remaining rental on MadMax Fury Road which was pretty good.

And yes, I checked Hulu for The Great, looks like a funny comedy with excellent cinematography by John, but alas...no HDR.

I still intend to buy Halloween and MI Fallout, in HDR.

Yes there is a way to use some 3rd party tools to munge an h.264 output into something that YouTube will allow as HDR, but that's fragile.

It works, it's not fragile but there is no longer a reason to use h.264. As well, you can use the mkvmerge hack to attach a 3D lut, improving the quality of the YouTube automatically generated SDR copy. But the hack also works for HEVC. I've been doing it for as long as YouTube has been accepting it, to have a better quality SDR copy which in reality is the most important, because that's how more people will be seeing it. The only reason there ever was to use h.264 was YouTube at first would not accept HEVC because they didn't want to pay the royalties. Now they accept it, so HEVC is much better.

YouTube is now supporting HDR10+ as well.

Most HDR content uses the P3 subset of 2020 primaries. The code values will produce very different results depending on what the primaries are set to. If the mastering display was P3, that doesn't impact anything. What matters is what primaries were used, which almost certainly were 2020.
__________________
Ben Waggoner
Principal Video Specialist, Amazon Prime Video

It would then appear I should at least try HLG as my SDR HDTV could play it then! I was thinking PQ before you reminded me of the cross-compatibility feature.

HLG is a compromise for live events and broadcast. If you're doing post production on your files and they aren't going to broadcast where HLG was the required deliverable, you are better off mastering to ST2084 PQ — aka HDR10 — and using Dolby Vision to create and export a separate SDR master. The Dolby Vision CM is built into Resolve Studio and works great.

Thanks, everyone! Lots of information will help greatly.

Tom. I am trying to create my master in the best form of HDR that I can see on the Pro Display XDR which appears to be P3 gamut Rec.2100 ST 2084 (which you mentioned is a form of Rec.2020 that I can limit to the P3 gamut. I can see the difference in the Resolve / Colour tab / CIE Chromaticity display that can display the boundaries for P3 and Rec.2020.

If you can see HDR now with the Resolve viewer and you are just preserving your archive for the future UHDTV - HDR, just skip the h.264/h.265 steps, don't worry about the metadata, just archive your projects and watch them from the Resolve viewer. Later, when you have a UHDTV with HDR, you can create playable media files on flash drives, or save them to YouTube so you can share/monetize etc. If you are delivering to Netflix, it's not going to be on HEVC anyway.

I do not have a television capable of playing HDR (at least I don’t think my Samsung from 2009 does that, but I’ll check).

It won't. Too old.

So my thinking do the grade to play on my Pro Display XDR and save that for displaying later when we get a 4K television. Maybe by the time that happens there will be a true 4K DCI (P3 4096x2160) option on a television, but for now it would letterbox on the UHDTVs. Wanting to do it right nonetheless so if and when either of my narrative projects take off, I’ll know what to do.

It would then appear I should at least try HLG as my SDR HDTV could play it then! I was thinking PQ before you reminded me of the cross-compatibility feature.

HLG is a compromise for live events and broadcast. If you're doing post production on your files and they aren't going to broadcast where HLG was the required deliverable, you are better off mastering to ST2084 PQ — aka HDR10 — and using Dolby Vision to create and export a separate SDR master. The Dolby Vision CM is built into Resolve Studio and works great.

I agree with this. HLG supports 17 stops of DR which is good, but the advantage of larger color volume of Dolby Vision, HDR10/HDR10+ is not shared with HLG.

I'm surprised by this. I haven't actually had any experience with it, but the dynamic metadata only seems useful (to me) when dealing with content mastered to very high light levels that exceed the capabilities of a given display. For example, content mastered to a 2000 nit peak being displayed on a ~700 nit display (like an LG OLED for example). In this case, only the brightest specular highlights would likely exceed 700 nits. Based on that, I could see having precise tone mapping metadata defined being helpful to improve highlight detail, but that's about it.

HDR10+ specifies the metadata, not how the tone mapper will use that information, so its behavior will be less predictible than Dolby Vision, where Dolby provides the tone mapper and certification as well.

There are two ways static metadata can be used - on-device player and over HDMI. Over HDMI is more limited as you don't get much lookahead - maybe you get the metadata one frame ahead. When it's in-player the bitstream itself stores the metdata in the clear, and it can be extracted from the whole GOP in advance, or even from future GOPs. That allows the tone mapper to know how much headroom it needs to leave for future variability. Take, for example, your 700 nit display playing content with a MaxCLL of 2000. Using just static metadata, it might have 700 nits map to 600 nits, and then save 600-700 as a rolloff region so you don't get a big flat white blob on highlights. But if the tonemapper knows that the whole shot doesn't have anything above 600, it can go all the way up to 700 for that shot.

Also, it's not just about luminance but also chrominance. Because of how RGB color volumes work, the higher the peak brightness that can be played, the more saturated colors can be farther from the luma midpoint. And plenty of cheaper HDR displays can't do P3 all the way up past 1000 nits. Those displays also need headroom for chroma, so maybe it'll only go up to 90% of saturation most of the time in case there's some stuff up against the master-display color volume. If the tonemapper knows what the most saturated colors in a given shot are, it can go right up to the maximum the display can show without leaving any headroom. This can be a big deal, since limited chroma gets into tradeoffs of reducing saturation (better) or shifting hue (worse).

Everything I've read said its a very small improvement on HDR10, and that going to full fat Dolby Vision (e.g. Profile 5) is a much bigger improvement. I do have a lot of experience with that and am generally more sold on Dolby Vision as a solution for OTT in general, given the dynamic shaping into 10 bit IPT during encoding and 16 bit RGB reconstruction in the TV, plus Dolby having more control over the TV processing (versus often terrible processing rife with unnecessary format conversions that would otherwise engage).

This is really going to depend on content, display, and tonemapper. Dolby Vision is going to be more reliably decent. But equally good HDR10+ and Dolby Vision tonemappers should produce pretty similar quality results.

One other advantage of HDR10+ is it has lower complexity than DoVi. DoVi Profile 5 requires constructing a new intermediate frame based on the non-backwards compatible base layer, the dynamic metadata, and display characteristics. While that can be done with HDR10+, it's also possible to just decode the HDR10 base layer and then use the tonemapper for everything else. Which is why some devices might only be able to do DoVi Profile 3 to 24p, Profile 5 to 30p, and HDR10+ to 60p.

This can also save power on mobile devices.

HDR10+ can save power/compute relative to HDR10 original flavor, because the decoded frame doesn't need to be analyzed to determine its luma and chroma ranges; that can be just read from the metadata.
__________________
Ben Waggoner
Principal Video Specialist, Amazon Prime Video