HDR Discussion Thread

[DisplayCalNoob]

Originally Posted by Geoff D

I always play around with the RGB settings whenever someone chimes in and says that it transforms their viewing experience, and it never does a damned thing on the ZD9. HDR10 looks exactly the same, DV looks exactly the same.

Maybe being a TV led display is the difference. When playing Spears disc, Gamut colors are limited with the player set to RGB. I can only get yellow to display, player back to YCbCr and all colors are available in the Gamut.

[BrownianMotion]

Originally Posted by DisplayCalNoob

Maybe being a TV led display is the difference. When playing Spears disc, Gamut colors are limited with the player set to RGB. I can only get yellow to display, player back to YCbCr and all colors are available in the Gamut.

Same thing on PC. I have to set my PC to YCC422 in the Nvidia control panel to get a proper HDR10 image. On RGB, everything is washed out.

[Geoff D]

Originally Posted by DisplayCalNoob

Maybe being a TV led display is the difference. When playing Spears disc, Gamut colors are limited with the player set to RGB. I can only get yellow to display, player back to YCbCr and all colors are available in the Gamut.

Even aside from player/led DV, it makes no difference with HDR10 content, it doesn't make it look all washed out.

[BrownianMotion]

Originally Posted by Geoff D

Even aside from player/led DV, it makes no difference with HDR10 content, it doesn't make it look all washed out.

To be fair, it only happens on PC for me. On my UHD player or Fire Stick, I can set it to RGB and there's no issue. I assume it's because these two devices automatically switch to YCbCr for HDR content.

Are you changing this setting directly on your TV or on an external device?

[Geoff D]

Originally Posted by BrownianMotion

To be fair, it only happens on PC for me. On my UHD player or Fire Stick, I can set it to RGB and there's no issue. I assume it's because these two devices automatically switch to YCbCr for HDR content.

Are you changing this setting directly on your TV or on an external device?

External device, using the Panasonic 820 or OPPO 203. ZD9 TV automatically adjusts to the colour space, which is basically why I don't see any difference.

Even when the source device is mapping Video/Legal levels to PC/Full levels (called RGB Enhanced on the Panny player) the TV auto adjusts. But if I were to manually force Full levels on Legal content using the TV's settings then everything is washed out to buggery because the black level of the content is now much too high for the chosen space (Full is 0 for black rather than 16 for 8-bit Legal, and 0 rather than 64 for 10-bit Legal). If I manually force Legal levels on Full content then the situation is reversed, it massively clips the blacks because the incoming black level is now much lower, but this is the time-honoured workaround for content that's been incorrectly mapped from Full levels, like Shout's Blu-rays of Road House and Transformers the Movie.

[DisplayCalNoob]

Originally Posted by BrownianMotion

To be fair, it only happens on PC for me. On my UHD player or Fire Stick, I can set it to RGB and there's no issue. I assume it's because these two devices automatically switch to YCbCr for HDR content.

Are you changing this setting directly on your TV or on an external device?

The two different color spaces also have an affect on sharpness. YCbCr with sharpness at 0, means no moire effect and the PQ is sharp. RGB sharpness at 0, PQ is soft.

I assume its because YCbCr, Y is Luma. So moire effect, ringing and other artifacts appear sooner. RGB, luminance isn't seperated from each color channel.

The LG UP970 manual describes RGB as meant for DVI connections.

[Penton-Man]

youngins, a new free webinar series –
https://www.smpte.org/sections/hollywood-section?action

[mrtickleuk]

Originally Posted by Geoff D

I thought the whole point of HLG was exactly that's it's backwards compatible in this way, that a non-HDR piece of equipment will just 'see it' as SDR? Or am I missing something here?

There are two entirely separate issues, but both are happening.

1. The Colour Space. If the content is mastered at BT.2020 (as it is in these cases), and your crappy V1 set top boxes wrongly flag this as BT.709 on their HDMI outputs, then - even if you have a modern TV which knows about BT.2020 and BT.709, the colours look wrong.
Also, if you have an SDR-only TV, the colours look wrong.
So Sky are screwing over a very large number of customers. They are embarking on a slow, agonising programme of replacing those set top boxes, after they've started the service. Only a small number of their boxes work correctly. This is doing everything in the wrong order because in the meantime, those customers do not have access to a version of the programme which will look correct for them even though they are paying a very high extra charge for it!

2. The EOTF. This is what you were mentioning. This is where you send the HLG EOTF to an SDR-only TV, and trust that it'll look ok even though the SDR-only TV is expecting a Gamma EOTF. Just hope they won't notice. SDR-only therefore customers get a compromised experience, which isn't as good as the SDR-only broadcast that they used to get. So, they are being short-changed.

(My understanding is that (2) was intended to save costs in TV production pipelines, to avoid replacing / duplicating whole sets of kit with critical monitoring still being done on HDR-capable displays; but this wasn't to then inflict the wrong version on real customers as well!?)

My understanding is that item (2) only works, and "using a common stream for all" only works, if you severely restrict your creators and limit the whole world to BT.709, removing one of the best things about our new work - the WCG.

All this in the context of that shameful back-slapping on LinkedIn too. Everyone involved at Sky should be thoroughly ashamed of themselves

I'm happy to be corrected on both those understandings, of course. However, launching a service knowing it'll look wrong for all customers on the majority of older boxes, despite knowing they will have no alternative which looks correct? No excuses.

[Geoff D]

Fair enough on the first point, as flagging the wrong colourimetry can cause some oddness for sure, but as to the EOTF I'm still confused, because that's how HLG is supposed to work. It's not like the first 100 nits of the signal aren't graded and then the grading takes over from there just when you get into HDR space. People are still getting an SDR that looks fine.

I don't know if you've got the Spears and Munsil UHD Benchmark but the demo Montage on there has an HLG version too and if you just play it in SDR (which it does automatically anyway, I'm not aware of there being a flag that auto-trips HLG being played from disc) then, well, it looks like SDR. A bit pale, a bit flat, 'twas ever thus. You mention the SDR TV expecting a Gamma-encoded signal but you're aware of what HLG stands for, right? Hybrid Log Gamma?

That material on Stacey's disc is encoded in SDR 2020 so that plays to your wider point about the colour space problem, and I get that the issues of that and the EOTF are intertwining here, but on paper then the HLG EOTF is doing exactly what it was intended to do by the BBC, NHK et al when they designed it.

But the colour space snafu is a separate issue and one that isn't easily solved with one stream. The need for proper representation of different colour spaces necessitates a separately converted HLG to SDR stream anyway to give the proper 'look' on an SDR 709 display (the BBC have LUTs available to license for this exact purpose). Which of course totally undermines the whole "HLG only needs one stream" thing.

[DanBa]

HDR - SDR backward compatibility has always some restrictions.
https://www.avsforum.com/forum/25-hd...l#post59760386

"SL-HDR1 is another HDR dynamic metadata technology, which serves a different purpose than Dolby Vision or SL-HDR2. SL-HDR1 is intended to enable the service provider to emit an HDR/2020 service in an SDR/709 format that can be “reconstructed” to HDR/2020 by the receiver.

HDR/2020 receivers that can interpret the SL-HDR1 metadata can present the HDR/2020 format to the viewer. The SDR/709 content can be displayed by receivers that cannot display HDR/2020. In this way SL-HDR1 provides a measure of backward compatibility for both HLG and PQ-based HDR content.

It should be noted that SL-HDR1 requires 10-bit encoding, and so may not help address legacy SDR/709 receivers that are only capable of 8-bit decoding."
https://ultrahdforum.org/wp-content/...V2.3-final.pdf

[Geoff D]

Pity that no-one actually uses that version, although Stacey has naturally had a look and will be putting that onto the next edition of S&M I think?

[Penton-Man]

Originally Posted by Penton-Man

https://www.sagaftra.org/files/sa_do...r%206-1-20.pdf

follow-up regarding film and TV production in Ca. -
https://www.latimes.com/entertainmen...ood-production

[DanBa]

Originally Posted by DanBa

Review of CHiQ A5U 4K UHD home theater projector compatible with Dolby Vision
xhttps://www.youtube.com/watch?v=KDxzd40gv-4

The Dolby Vision module has been removed because Dolby has deemed that the performance of all current consumer projectors inadequate to meet the Dolby Vision standard.
https://w ww.youtube.com/watch?v=k1CpxlJpQDo

However, projector enthusiasts are continuing to enjoy Dolby Vision movies using the Low Latency Dolby Vision (LLDV or Dolby Vision color volume adaptation) function of some media players via a HDMI interface spoofer which falsely informs the media player that the projector is LLDV compatible.
https://www.avsforum.com/forum/465-h...l#post58747332

[mrtickleuk]

Originally Posted by Geoff D

Fair enough on the first point, as flagging the wrong colourimetry can cause some oddness for sure, but as to the EOTF I'm still confused, because that's how HLG is supposed to work. It's not like the first 100 nits of the signal aren't graded and then the grading takes over from there just when you get into HDR space. People are still getting an SDR that looks fine.

I don't know if you've got the Spears and Munsil UHD Benchmark but the demo Montage on there has an HLG version too and if you just play it in SDR (which it does automatically anyway, I'm not aware of there being a flag that auto-trips HLG being played from disc) then, well, it looks like SDR. A bit pale, a bit flat, 'twas ever thus. You mention the SDR TV expecting a Gamma-encoded signal but you're aware of what HLG stands for, right? Hybrid Log Gamma?

Thankyou, Geoff. That is precisely the sort of correction that I needed . I do have the disc but only a Samsung K8500 player. Haven't experimented much with the HLG clips though I do admit.

But the colour space snafu is a separate issue and one that isn't easily solved with one stream. The need for proper representation of different colour spaces necessitates a separately converted HLG to SDR stream anyway to give the proper 'look' on an SDR 709 display (the BBC have LUTs available to license for this exact purpose). Which of course totally undermines the whole "HLG only needs one stream" thing.

Indeed. Sky are screwing over many customers by doing this, and it's not a free service either... . Their supporters are still heavily downplaying this on their forums, too.

[Geoff D]

You know, with all the focus on projektor owners using the LLDV spoofing I clean didn't realise that it could be used to add DV to any HDR TV, though with all those custom profiles clearly it's not a set and forget solution just yet.

lol @ all the glowing testimonials from people forcing DV on SDR content though. Tacking it onto HDR10 is one thing, but slapping it onto SDR? Nah.

[Steedeel]

Originally Posted by mrtickleuk

Thankyou, Geoff. That is precisely the sort of correction that I needed . I do have the disc but only a Samsung K8500 player. Haven't experimented much with the HLG clips though I do admit.



Indeed. Sky are screwing over many customers by doing this, and it's not a free service either... . Their supporters are still heavily downplaying this on their forums, too.

Heck, Sky still charge for a HD upgrade. It’s beyond pathetic imo. I am very close to cancelling as I only have it for the football and I’m even losing interest in watching top flight football. My team is two leagues away and only feature on Sky three or four times a season. If the EFL (English Football leagues) could in my opinion, stop treating EFL fans like second class citizens and waver the 3pm live blackout, fans could then buy a pass and watch games on the tv (just away games in my case) via a smart app. It seems the Premier league can make exceptions, why can’t the EFL?

But yeah, Sky are about to lose a customer. Sky Q is a bank breaker for many. If they lost football, they become irrelevant.

If I want impressive 4K, I have my discs.

[BrownianMotion]

Originally Posted by DanBa

The Dolby Vision module has been removed because Dolby has deemed that the performance of all current consumer projectors inadequate to meet the Dolby Vision standard.
https://w ww.youtube.com/watch?v=k1CpxlJpQDo

However, projector enthusiasts are continuing to enjoy Dolby Vision movies using the Low Latency Dolby Vision (LLDV or Dolby Vision color volume adaptation) function of some media players via a HDMI interface spoofer which falsely informs the media player that the projector is LLDV compatible.
https://www.avsforum.com/forum/465-h...l#post58747332

Very interesting.

My main TV already supports Dolby Vision, but I may try this on my HDR10-only set.

Is the Vertex the only model that can do this, or can any of the other HDFury products accomplish the same thing?

[Penton-Man]

Originally Posted by mrtickleuk

Colour

Warning - the more seasoned membership (mid-40’s and older) here may find somewhat depressing the pictures and discussion at timestamp 9:40 - https://osa.zoom.us/rec/play/u8codOG...gV5qOhCJfr9aPO

not to worry though, as phaco sx. is low risk and effective

[Penton-Man]

harkening back to a concept post on the very first page of this thread, over 4 years ago - https://forum.blu-ray.com/showthread...e#post12135751

a “pro’s pro.” “He shoots a great, thick ‘neg’– digital or film — so we have everything there to work with when it comes to shaping the look of each shot.”
https://www.company3.com/a-different...angster-movie/

^ if one were to choose a good candidate for an HDR iteration, that would be Capone

[lgans316]

I think Panasonic UB820 player can force DV on SDR content on its Internal apps.