HDR Discussion Thread

[BrownianMotion]

Originally Posted by mrtickleuk

There is another very very important facet to the "SDR within HDR" problem. All LCDs have to max out the backlight in HDR mode. Blacks are no longer black, you get milky grey, halo-ing around subtitles etc. It looks horrible, and takes a lot more power to display the same thing, but worse (so is very bad for the environment). This is why if it's going to be SDR, it's better to just let it be SDR.
You could even say "if it's not very HDR, it's better to just let it be SDR" and then we have a debate about what "very HDR" should mean. But that is a hornet's nest

This is where dynamic metadata probably has its biggest impact. It makes the backlighting on LCDs, especially edge-lit displays, more efficient, because it doesn't simply consider a single data point.

[DisplayCalNoob]

Originally Posted by Geoff D

My point there is that most display tech *itself* - in terms of sheer nits, contrast etc - can easily handle these kinds of low APL presentations on paper, even the crappy supermarket special TVs, but it's the processing/mapping/tracking/whatever that's letting the display tech down, and sometimes drastically affecting this kind of low APL HDR content by making it look much too dim and dark. In these cases then dynamic tone mapping is a godsend, but if the in-house mapping/tracking/whatever worked as to how many professionals and enthusiasts wanted or assumed it should work (by tracking the first 50% of the PQ EOTF e.g. 100 nits accurately and then mapping or rolling off the rest according to what peaks the TV can do) we'd have less problems with "too dark" HDR IMO.

I never have understood the misinformation being passed by those who were supposedly in the know. Personally, even when it comes to display manufacturers, the resistance to supporting DV I think led to some of it. The idea of just chasing peak nits, when it is not just peak nits that are tone mapped. Edge lit displays even though the Pulsar, was the prime example for what a HDR display should have tech wise.

[DisplayCalNoob]

Originally Posted by BrownianMotion

This is where dynamic metadata probably has its biggest impact. It makes the backlighting on LCDs, especially edge-lit displays, more efficient, because it doesn't simply consider a single data point.

Edge lit not so much, light control is so limited that blacks, shadow detail would suffer. There's nothing dynamic metadata can do for that tech.

[BrownianMotion]

Originally Posted by DisplayCalNoob

Edge lit not so much, light control is so limited that blacks, shadow detail would suffer. There's nothing dynamic metadata can do for that tech.

That's not true at all. Edge lit is exactly the type of technology that can benefit from dynamic metadata. If peak and average brightness for each scene is known in advance, that would minimize the issues inherent in the dimming on such displays.

[Penton-Man]

Originally Posted by Geoff D

So you resorted to posting on there during your enforced 'social distancing' from this place? Heh.

I’ve occasionaly shared other exclusive information to the appreciative audience there and also other places too prior to posting it on this thread, e.g. https://www.avsforum.com/forum/44-mo...l#post59156928 . I think Stacey’s done the same in AVS’s Display Calibration subforum. I believe those good AVS folks are, at a very minimum, co-equal aficionados of HDR and exclusive information. No?

In any case, for technological escapism (from long distance worried communications to Docs regarding daily oxygen levels, platelet counts, ferritin levels, etc. with an out of state loved one), last night I listened to the following podcast hosted by the Beamr software encoder gurus and although many of the concepts expressed by Michael Drazin (the SME on the front lines of that production) have been described in detail in this thread on previous pages, long before the Super Bowl aired, there are a few new insights in the later parts of the discussion, e.g. challenges to widespread (rather than regional) distribution of HDR live action sports, doing HDR shading, manufacturing 8K lenses (challenged by the physics of it) <– especially important to realize with regards to value added/or not for shots covering different types of sports - https://thevideoinsiders.simplecast....odes/episode40

[Penton-Man]

Anime - https://netflixtechblog.com/bringing...e-fa68105067cd

[IntelliVolume]

If I'm using the Panasonic UB9000's HDR Optimizer -- which is supposed to apply its own tonemapping for static HDR10 metadata, supposedly, according to Panny, for improved performance over a display's own efforts -- do my display settings still need to be in their default HDR positions?

In other words, when it senses an HDR signal, my Samsung automatically maxes out backlight and contrast, and puts local dimming on high...but if I'm using the HDR Optimizer of the disc player, do those settings still matter or apply? Should they be left alone if the player is supposedly doing the tonemapping work?

[DisplayCalNoob]

Originally Posted by BrownianMotion

That's not true at all. Edge lit is exactly the type of technology that can benefit from dynamic metadata. If peak and average brightness for each scene is known in advance, that would minimize the issues inherent in the dimming on such displays.

The amount of visible artifacts, makes edge lit not worth the time. Day time bright scenes may fair well, but dark scenes with small bright highlights no.

[DisplayCalNoob]

Originally Posted by IntelliVolume

If I'm using the Panasonic UB9000's HDR Optimizer -- which is supposed to apply its own tonemapping for static HDR10 metadata, supposedly, according to Panny, for improved performance over a display's own efforts -- do my display settings still need to be in their default HDR positions?

In other words, when it senses an HDR signal, my Samsung automatically maxes out backlight and contrast, and puts local dimming on high...but if I'm using the HDR Optimizer of the disc player, do those settings still matter or apply? Should they be left alone if the player is supposedly doing the tonemapping work?

You would probably get a response in the dedicated thread. If I had to guess, the optimzer has levels. So just test all options and look for gains and losses.

[IntelliVolume]

Originally Posted by DisplayCalNoob

You would probably get a response in the dedicated thread. If I had to guess, the optimzer has levels. So just test all options and look for gains and losses.

That's beyond my comprehension level with regard to HDR (the gains/losses etc.), but there are a number of sliders in this Optimizer menu that can be adjusted -- right now I have em all at "0" as I don't really know what they're all supposed to do...

This seems so confusing, though, in general; we were originally told that a display should be left at its default HDR settings when receiving an HDR signal -- that is, just let it send backlight and contrast to maximum, leave the highest local dimming (for an LCD) setting alone, et. al. Now, with systems like the HDR Optimizer, I'm not sure if those TV settings are right anymore, being that the disc player is doing something with the tonemapping….but at the same time, I don't know what I should be touching in the Optimizer menu (I just leave it turned on and don't touch the sliders in the menu for Tone Curve, etc.).

[IntelliVolume]

Originally Posted by DisplayCalNoob

The amount of visible artifacts, makes edge lit not worth the time. Day time bright scenes may fair well, but dark scenes with small bright highlights no.

I can attest to the downsides of the edge lighting system. ABSOLUTELY SUCKS for HDR with black levels, lighting up the whole screen like Christmas and rendering blacks a nasty foggy grey instead.

I wish there was a way -- aside from switching to another TV tech a la OLED or FALD -- to mitigate these extreme blooming issues with HDR on a Samsung such as mine, but I'm not sure if lowering the gamma or brightness (black) level is the right way to go about this. Wouldn't this just crush blacks in darker scenes?

[BrownianMotion]

Originally Posted by DisplayCalNoob

The amount of visible artifacts, makes edge lit not worth the time. Day time bright scenes may fair well, but dark scenes with small bright highlights no.

Which is exactly why dynamic metadata will help that display technology.

Edge lit will always be inferior, even with Dolby Vision or HDR10+, but it will at least have more efficient backlighting than it does with static metadata.

[sapiendut]

Yeah. Edge lit is a sorry excuse of display technology.

[IntelliVolume]

Is there a way to mitigate the nasty effects of edge lighting (extreme bloom, grey-ish blacks) using a display's controls or possibly the Panasonic HDR Optimizer sliders?

Would, for example, dropping the display's gamma or black level sliders down stop some of the HDR blooming?

[DisplayCalNoob]

Originally Posted by IntelliVolume

I can attest to the downsides of the edge lighting system. ABSOLUTELY SUCKS for HDR with black levels, lighting up the whole screen like Christmas and rendering blacks a nasty foggy grey instead.

I wish there was a way -- aside from switching to another TV tech a la OLED or FALD -- to mitigate these extreme blooming issues with HDR on a Samsung such as mine, but I'm not sure if lowering the gamma or brightness (black) level is the right way to go about this. Wouldn't this just crush blacks in darker scenes?

Yes, your best bet is bias lighting, assuming you watching in a dark room.

[Penton-Man]

^ Perhaps?, at least in the traditional sense, for this too – http://www.displayweek.org/2020.aspx
which is unfortunate because there is to be a substantial amount devoted to HDR and miniLEDs

[IntelliVolume]

Originally Posted by DisplayCalNoob

Yes, your best bet is bias lighting, assuming you watching in a dark room.

Oh, yeah, I considered that (and was advised to get a kit for the back of the set), and, yes, I'm watching in a dark room...the thing is, my display is in a wall unit/entertainment center, and three of its sides (save for the bottom, as the TV is on the stand) are sort of "flush" with the cutout for it, so there's really no room for the light to peek through (except for, again, the bottom which is open).

This is why I put the idea of bias lighting on the back burner, but I may consider it again; do you think it could still work being that three of the TV's sides are kind of covered?

Are there any display settings I could try to mitigate this...maybe dropping contrast or brightness (black level)? Maybe gamma?

[Geoff D]

Originally Posted by mrtickleuk

There is another very very important facet to the "SDR within HDR" problem. All LCDs have to max out the backlight in HDR mode. Blacks are no longer black, you get milky grey, halo-ing around subtitles etc. It looks horrible, and takes a lot more power to display the same thing, but worse (so is very bad for the environment). This is why if it's going to be SDR, it's better to just let it be SDR.
You could even say "if it's not very HDR, it's better to just let it be SDR" and then we have a debate about what "very HDR" should mean. But that is a hornet's nest

Hmmm. I think some people are doing a bit too much hand-wringing over this issue as a mere disguise for their crusade to have all HDR be at the sort of level that delights the self-appointed "nit wh0res" out there. I mean, they've had four years to tub-thump about the poor HDR performance of supermarket special LCDs but they only chose to do it now? And besides, a key flaw in this argument is that all the things you're describing would happen on those poorer TVs even with a Light Cannon™ HDR grade anyway. So what if they could show some brighter nits in some scenes? They'd still have the backlight boosted to max and would still wreck the black level, still have lots of blooming and flashlighting, still be very bad for the environment etc. (Though I wonder if the hand-wringers are worrying about the state of the planet when they're watching something in super bright HDR though?)

And by the way, if you think "all LCDs" look as janky as you describe in HDR then you clearly haven't seen the ZD9.

[Geoff D]

Originally Posted by DisplayCalNoob

I never have understood the misinformation being passed by those who were supposedly in the know. Personally, even when it comes to display manufacturers, the resistance to supporting DV I think led to some of it. The idea of just chasing peak nits, when it is not just peak nits that are tone mapped. Edge lit displays even though the Pulsar, was the prime example for what a HDR display should have tech wise.

Part of the problem is that manufacturers all want their own special sauce inside their TVs, they all want to do things differently to make their sets stand out from the competition. Unfortunately this extended to the whole "HDR mapping" thing, when someone REALLY should've knocked their heads together and told them that using 101 different approaches for mapping/tracking absolute luminance HDR was going to be such a bad idea for the format. "By all means slather your special sauce over the end result if you want, but let's at least get some sort of standardised tone mapping approach in place so these sets can all get the fundamentals correct, and what you do with the nits past that point is up to you. Wait, guys, where are you all going?!?".

Going one further and having customisable mapping/tracking controls as Kris suggested would've been even better, dizzyingly complex for noobs perhaps but as the knowledge base widened then more and more of this information would've gotten out there and people could learn as they go. But as the processing inside all those earlier HDR TVs was in gamma space rather than in native PQ space (something which Stacey Spears has mentioned before) then I'm not surprised they didn't have the kind of granular control over mapping/tracking that they really needed, they were just converting PQ into gamma so that the TV's processing could interpret it with its gamma-based controls, and then converted the adjusted signal back into PQ for output. I mean, even now there are very few TVs that allow this sort of explicit control over the trajectory of the mapping/tracking, though the 2019 LG OLEDs deserve a shout-out for their ability to set those things during calibration.

[frogmort]

As a newbie with all this, it just seems incredibly daunting and confusing. Why was there not a basic standard for all of this? I should be able to plug this into that, then put in a disc and it should look great, right? No, I have to get several PhD's to make it work right.

Makes me scared to branch out past good ol' fashioned 1080p.