I Have Published a HDR10 to HLG Converter

[kolak]

Originally Posted by wswartzendruber

PQ: Overcomplicating consumer video since 2016.

Not sure if it's really that complicated. Idea behind it is good.

I don't know where this big difference is coming from though. I don't believe it's due to compression overshoots (it's jus too much), but this may be more clear when I use few tools to measure MaxCLL. Resolve is not the best way when you have finished (compressed) master.
MaxFALL aligns, which is somehow good news. Supplied DV metadata is also aligned with master and matches one generated in Resolve. It's just MaxCLL.

[FranceBB]

Originally Posted by rwill

So its somewhat future proof instead of being a stop gap solution like HLG ?

Sure, I very much believe that the future is gonna be some sort of 12bit PQ with high enough nits and dynamically changing metadata. The biggest limit to achieve all this right now is consumer's hardware, but yeah I do believe that the future is gonna be PQ and one day, long long into the distant future, even newer better logarithmic curves as I think they're gonna be kept updated, a bit like Sony does for Slog, Canon does for Clog etc. The only difference is that when PQ was created, they made it so that it had so much room for manoeuvre that it was going to take years to fill the gap. Even nowadays, 6 years later, there aren't cameras with enough stops to be able to record as many frequencies as the ones needed to cover the whole PQ spectrum. There are movies that have been graded as high as 5000 nits, but that's not because the camera captured all of that but rather because it had special effects and the creator decided that it was worth making them that high. For instance, the old Harry Potter movies were shot in LogC and had just a bunch of nits, but due to the special effects and all the magic things they've been able to master them at over 2000 nits.

Anyway, in a nutshell: is PQ future proof?
Probably yes.

[kolak]

As for today cameras are not the main limitation, but way more displays. 10K nits will need some time and development for sure and probably we don't even need more for the eye, so PQ should be quite future proof.
Eye can see around 20 stops if I remember well, but not at the same time (only after some adaptation time).

[wswartzendruber]

Given a reference viewing environment (5 nits ambient lighting), does exceeding 1,000 nits have any real use?

[kolak]

Even in dark room more than 1K nits still makes difference.
I've only seen 2K masters on Dolby monitor, but those who saw 4K nits say it still makes difference compared to 1K. Not sure about 10K though.

[Balling]

Originally Posted by rwill

PQ is an absolute range. You cannot re-scale it. You cannot just say that a 10k nits pixel is 1k nits. How would this even work anyway ?

That is the whole point of the word perceptual in PQ, our eye does not see the difference between 10000 nits of display and 1 billion nits of the sun, it is the range of light that makes a difference (unless you put two TVs side by side thus breaking your brain's adaptation).

>Sure, I very much believe that the future is gonna be some sort of 12bit PQ with high enough nits and dynamically changing metadata.

It is already the future. IPTPQc2 is 11.5 bits PQ. FEL is 12 bit. And no, you do need 12 bit Dolby Pulsar to present this. 12 bit is BT.2020 10000 nits, display is only 700 nits P3, so 10 bit is for smaller image. There is also RGB vs YCbCr and of course 4 subpixels. So more or less all I watch is 12 bit PQ.

[wswartzendruber]

Originally Posted by kolak

Even in dark room more than 1K nits still makes difference.
I've only seen 2K masters on Dolby monitor, but those who saw 4K nits say it still makes difference compared to 1K. Not sure about 10K though.

And it isn't annoying?

[kolak]

What do you mean ?
4K nits strikes with another level of visual impact (apparently).

[wswartzendruber]

As does looking directly into the sun, but that's uncomfortable to say the least.

So given a reference environment of 5 nits, does exceeding 1,000 nits serve any artistic purpose that anyone will appreciate? Or...does it just serve to have a larger number that marketing tells us is automatically better?

I mention a reference viewing environment combined with a max brightness value of 1,000 nits because that's HLG's baseline. If you have more ambient light, you can simply turn up the brightness, and the EOTF will perform the necessary adjustments to preserve artistic intent.

Essentially, I am attempting to figure out why everyone is not simply migrating distributed content over to HLG. Surely there must be artistic merit in exceeding 1,000 nits in a reference environment? Because that's the one thing it can't do.

Then again, it did take UTF-8 two decades to become the predominant encoding on the World Wide Web. See, UTF-16 was declared the future and that's what sophisticated people used. Except that...UTF-8 turned out to be so much easier to deal with.

[FranceBB]

Originally Posted by wswartzendruber

Essentially, I am attempting to figure out why everyone is not simply migrating distributed content over to HLG.

Probably because of the fact that HLG is hybrid so people with OLED won't be able to appreciate any added details on the blacks as the lower part of the curve is essentially SDR BT2020.

[kolak]

Originally Posted by wswartzendruber

As does looking directly into the sun, but that's uncomfortable to say the least.

So given a reference environment of 5 nits, does exceeding 1,000 nits serve any artistic purpose that anyone will appreciate? Or...does it just serve to have a larger number that marketing tells us is automatically better?

I mention a reference viewing environment combined with a max brightness value of 1,000 nits because that's HLG's baseline. If you have more ambient light, you can simply turn up the brightness, and the EOTF will perform the necessary adjustments to preserve artistic intent.

Essentially, I am attempting to figure out why everyone is not simply migrating distributed content over to HLG. Surely there must be artistic merit in exceeding 1,000 nits in a reference environment? Because that's the one thing it can't do.

Then again, it did take UTF-8 two decades to become the predominant encoding on the World Wide Web. See, UTF-16 was declared the future and that's what sophisticated people used. Except that...UTF-8 turned out to be so much easier to deal with.

It's not just about brightness itself. It's about color volume, which makes huge impact on your brain.
I'm not going to argue with you as I don't have enough expertise. I can only pass what Dolby people said. They done a lot of study including many tests on random people (not just engineers). 4K nits is apparently not "burning" your eyes at all.
Atm. color volume is an issue even for 1K content as OLEDs due to technology limitations makes signal pure what above some nits (if I remember well they fall apart already at 200 or so), which is not how it should be.
Sony reference OLED monitor was RGB based and it behaved much better. There is video on YT (from Vincent) where it can be seen compared to Apple HDR screen.

[wswartzendruber]

Originally Posted by FranceBB

Probably because of the fact that HLG is hybrid so people with OLED won't be able to appreciate any added details on the blacks as the lower part of the curve is essentially SDR BT2020.

What you're saying implies that HLG has banding issues in dark regions on devices that can display absolute black.

[FranceBB]

Originally Posted by wswartzendruber

What you're saying implies that HLG has banding issues in dark regions on devices that can display absolute black.

Nope, not banding, it's still 10bit and it works just fine.
The only thing I'm saying is: suppose you shoot a scene in LogC and it's in a relatively dark environment.
When you convert to PQ, you're gonna be able to preserve every stop recorded by the camera, while when you convert to HLG only the ones in the middle and high levels are gonna be preserved. In other words, if you have like a dark environment, in HLG it will be averaged out to black 64 while in PQ and LogC you're gonna be able to see different shades of black. Of course this isn't generally an issue and this is why: those details or rather values are artificially removed anyway during the grading even in PQ 'cause they're almost always full of noise.

If I wasn't on paid leave with my phone in my hand and no PC in sight I would have shown you.

[wswartzendruber]

Remember that I am arguing for HLG for consumer distribution only. It's certainly not anything you would ever want to capture or grade in.

So...is all that detail in the blacks useful for consumer viewing? I do not know the answer.

[rwill]

Originally Posted by wswartzendruber

Remember that I am arguing for HLG for consumer distribution only. It's certainly not anything you would ever want to capture or grade in.

So...is all that detail in the blacks useful for consumer viewing? I do not know the answer.

Is a Dolby Atmos Mix useful if most consumers use the built in TV speaker ? Yet there are people with really expensive audio setups for whom it is additional value.

[wswartzendruber]

Dolby Atmos is backwards compatible with both TrueHD and AC-3. And because of that, it's backwards compatible with simple stereo. And as Dolby controls all of this, there is no disagreement on what different things (MaxCLL) mean.

If video were to have Atmos' level of compatibility, we would be looking at something like HLG with a PQ enhancement layer and metadata.

Now that might actually be cool...

EDIT: Okay now I'm really thinking about this...

[nevcairiel]

Originally Posted by wswartzendruber

If video were to have Atmos' level of compatibility, we would be looking at something like HLG with a PQ enhancement layer and metadata.

Now that might actually be cool...

Its called Dolby Vision Profile 8.4.

iPhones record in that format in HDR mode. HLG base layer with enhancement metadata that turns it into PQ (plus the typical other metadata Dolby Vision includes to assist tonemapping etc).

[FranceBB]

Originally Posted by nevcairiel

Its called Dolby Vision Profile 8.4.

iPhones record in that format in HDR mode. HLG base layer with enhancement metadata that turns it into PQ (plus the typical other metadata Dolby Vision includes to assist tonemapping etc).

Yes and if you display it on an HLG only capable display or a BT2020 SDR only capable display or anything that doesn't read Dolby metadata (and even if you try to apply normal tonemapping algorithms that generally work on standard HLG, ignoring the Dolby metadata) it will look like crap, thus defeating its original purpose.
I know 'cause I stumbled on this early last year:

https://forum.doom9.org/showpost.php...5&postcount=94

[wswartzendruber]

Did Profile 8.4 not exist when the UHD Blu-ray spec was being done? Because it seems obvious that it should have used that.

EDIT: That was a stupid question. HLG didn't exist when that spec was being drafted.

[nevcairiel]

Originally Posted by wswartzendruber

Did Profile 8.4 not exist when the UHD Blu-ray spec was being done? Because it seems obvious that it should have used that.

Dolby Vision is by far not open enough to be the sole way to do a high quality HDR representation on Blu-ray.

PQ is a good choice as it gives you high quality throughout the entire spectrum, and a lot of extra brightness for future-proofing.

HLG is a "compromise" format, not a high-quality format.

Originally Posted by FranceBB

Yes and if you display it on an HLG only capable display or a BT2020 SDR only capable display or anything that doesn't read Dolby metadata (and even if you try to apply normal tonemapping algorithms that generally work on standard HLG, ignoring the Dolby metadata) it will look like crap, thus defeating its original purpose.

Thats quite likely just Apples implementation of it, there is nothing that makes it inherently worse then eg. normal HLG.