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Author Topic: UHD 4K Blu-ray disc playing with "8-bit HDR"  (Read 4739 times)

madbrain

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UHD 4K Blu-ray disc playing with "8-bit HDR"
« on: June 03, 2020, 09:52:30 pm »

Reposting since the last post didn't make it, likely because of attachments.

When I play a UHD 4K Blu-ray disc in MC25 on my HTPC, specifically "Star Wars: Last Jedi" with an nVidia GTX 1050Ti GPU, JRiver switches the video mode to 2160p/24 Hz, and the "HDR" icon appears on my Optoma UHD65 projector soon after the mode switch.

However, I took a closer look at at the HDMI signal information using my Marantz SR-7011 receiver menu, and it showed that the signal is "4K:24 Hz, BT.2020 RGB, 8 bits". In other words, this is 8-bit HDR. See the first attachment.

If I play the same disc in my Sony UBP-X800 UHD BD player, the receiver says the HDMI signal is "4K:24 KHz, BT.2020 YCbCr, 12 bits", which is closer to what you would expect.

The colors look significantly different and better in the movie from the Sony player. I actually made an ISO backup of the disc to play in MC25, and froze the movie at the same section in both the Sony player with the physical disc, and with MC25 on the HTPC. I paused both around the same time (though not exact frame, but close), and switched inputs on the remote, and I can tell the same static frame has more contrast coming from the Sony. The projector is using identical settings for both cases, the so-called "HDR mode" preset.

Question :

How can I tell get MC25 to play HDR movies in either 10 or 12 bits as opposed to 8 bits ?

Relevant software settings :
a) In the nVidia control panel "change resolution" tab, I have it set to 3840x2160 at 60 Hz. The color settings are left to "Use default settings". When I look at the HDMI signal on the receiver, I can see that it the signal is "4K:60 Hz RGB 8 bits".
Do I need to change the system color settings to match the movie ? I was expecting MC25 to set those appropriately during the mode switch.
b) I have "Windows HD color" turned off in Windows Display settings. Do I need to set the desktop to HDR mode also to play HDR movies in MC25 ?
c) In MC25 video settings, I am using "Red October HQ" with default MadVR settings.
I have tried tuning a few things, such as :
- setting the "native display bidepth" to "10 bits (or higher)"
- changing the HDR setting to "passthrough HDR content to the display"
Neither resulted in any change in behavior. The output HDMI signal is still "4K:24 Hz, BT.2020 RGB, 8 bits".

Can somebody please help ?

Full hardware/software specs :

My hardware :
Asus Prime X470 Pro motherboard
AMD Ryzen 2700 CPU
16GB DDR4-2666
nVidia GTX 1050Ti 4GB video card
Hauppauge quad-HD tuner card (4 ATSC tuners)
Hauppauge HVR-1850 tuner card (1 ATSC tuner)
Aquantia AQN-107 10Gbe NIC

Audio :
Marantz SR-7011 receiver

Display :
Optoma UHD65 4K projector

Software :
Win10 x64 build 1909
JRiver MC 25 x64 25.0.115
nVidia drivers 445.87

I have also attached screenshots of the display identification and raw EDID data in MadVR.
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madbrain

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Re: UHD 4K Blu-ray disc playing with "8-bit HDR"
« Reply #1 on: June 03, 2020, 09:58:47 pm »

Capture of HDMI signal info from MC25 as shown by SR-7011 receiver.
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madbrain

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Re: UHD 4K Blu-ray disc playing with "8-bit HDR"
« Reply #2 on: June 03, 2020, 10:02:56 pm »

Capture of HDMI signal info from Sony UBP-X800 player as shown by SR-7011 receiver.
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madbrain

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Re: UHD 4K Blu-ray disc playing with "8-bit HDR"
« Reply #3 on: June 03, 2020, 10:32:29 pm »

EDID info attached.
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stewart_pk

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Re: UHD 4K Blu-ray disc playing with "8-bit HDR"
« Reply #4 on: June 04, 2020, 01:50:51 am »

I think your Windows desktop setting is probably 8 bit.
MadVR converts to RGB so having your desktop set to YCbCr there will be a conversion back by your video card.
The best way to watch HDR 4K content from MadVR is to configure it to do dynamic tone-mapping if your GPU can handle it.
Projectors are not HDR devices but if yours has dynamic tone-mapping built in and switched on then it's probably going to be easier and more straight forward to send it HDR.

https://www.cnet.com/news/why-you-shouldnt-expect-great-hdr-from-a-projector/
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madbrain

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Re: UHD 4K Blu-ray disc playing with "8-bit HDR"
« Reply #5 on: June 04, 2020, 04:17:45 am »

I think your Windows desktop setting is probably 8 bit.
MadVR converts to RGB so having your desktop set to YCbCr there will be a conversion back by your video card.
The best way to watch HDR 4K content from MadVR is to configure it to do dynamic tone-mapping if your GPU can handle it.
Projectors are not HDR devices but if yours has dynamic tone-mapping built in and switched on then it's probably going to be easier and more straight forward to send it HDR.

https://www.cnet.com/news/why-you-shouldnt-expect-great-hdr-from-a-projector/

Yes, my Windows desktop is set to 8 bit RGB. With 4K 60 Hz, 8 bits is the best you can do on HDMI 2.0 .

I tried to force my desktop to do YCbCr420 and 12 bits. In this case, MadVR indeed will send BT.2020 to the projector in 12 bits, and the color looks correct - same as they do from the Sony player. IMO, one shouldn't be required to downgrade the desktop's resolution from RGB to YCbCr420. I'm playing the movie full-screen, and MC has an opportunity to change the video mode, and indeed, does change it from 60 Hz to 24 Hz, and the color space from Rec 709 to BT.2020 . The only thing it doesn't seem to be able to change is the pixel depth and chroma sampling, for some reason.

It should be noted that the Sony player can send 12 bits in YCbCr444 to the projector. There is enough bandwidth on HDMI 2.0 to do that at 24 Hz. I'm unable to find any way to get MediaCenter + MadVR to do the same. The best it can do is YCbCr420 12 bits for 4K/24 Hz.

In fact, my Sony player has custom HDMI settings. I was able to force it to use RGB 12 bits also. It works fine because there is once again enough bandwidth to do RGB 12 bits at 4K / 24 Hz on HDMI 2.0.

Once the move player was sending all 12 bits, I couldn't discern any difference in the movie between YCbCr444 12 or RGB 12 bits from the Sony player. YCbCr420 12 bits from MC25 also looked pretty much the same. That's probably because the Blu-ray discs themselves are encoded in 420 chroma subsampling, so there is no benefit to going higher.

As an experiment, I also forced the Sony player to play the movie at 60fps, by disabling the "24p" playback option. I had also forced RGB in the player. In this case, the Sony player sets the video signal to 4K 60 YcCbCr BT2020. The Marantz receiver is unable to figure out the pixel depth, oddly. The colors look correct, though.

I'm aware that MadVR has tone mapping for HDR to SDR. I have played with it, actually. I find that I personally prefer to have the HDR processed by my UHD65 projector. I have read threads on AVSForum that recommend using the MadVR tone mapping with this projector, in fact. I just haven't found it to be preferable in my environment. I have a fully light controlled room, and a very high gain screen - DA-Lite High Power. Either 2.4 or 2.8 gain. It's a 17-year old 106" screen. Somehow, that screen seems to do wonders with HDR on the UHD65 when using the Sony UHD BD player.

I'm well aware that consumer projectors aren't truly HDR displays. They can't achieve the necessary brightness. However, IMO, it is important for the colors to look correct, and they are just not correct when sending BT.2020 over just 8 bits.
Try as I might, I haven't been able to get my Sony player to misbehave into doing the same. I'm not sure where the fault lies exactly, whether it's Microsoft, nVidia, MC25 or MadVR. But it currently doesn't make for a good user experience.

Microsoft and nVidia probably have a fair bit of responsibility here. If I use run the desktop at 4K 60 Hz, the nVidia drivers defaults to 8 bit RGB. Then, if I enable "Windows HD color", it switches to sending BT.2020 at 8 bits, which is worse than useless, IMO. All it does is get the display to claim it's showing HDR, when it's actually not providing any benefit.

I would welcome some options in MC25 and/or MadVR to set the color depth and chroma subsampling. Ideally, these should go in the "custom modes" tab of MadVR display modes. At the moment, only the width, height and Hz can be customized. It's not possible to select either the bit depth (8, 10, 12 bits) or the chroma subsampling (YCbCr420, 422, 444, RGB). Only the nVidia control panel can do those, but that's for the desktop only. If it was possible to select a combination of all these in MadVR, I think including a bunch of presets that make sense for BD discs, along with some code to avoid ever trying to pack HDR data in 8 bits, so that non-sensical modes don't get selected.

I also just bought a brand new 82" Samsung Q70 TV purchased at Costco over the week-end, which may actually be capable of real HDR. It's still only HDMI 2.0, though, not 2.1. There was an LG HDMI 2.1 in the store that was 86" and about $700 less than the Samsung. Unfortunately, its picture looked far worse from all standpoints. I checked the ratings on some review site, and they confirmed that it was a night and day difference. The LG OLED probably outperformed both, but it was 2.5x the price and not on display.

So, I also have a HTPC hooked up to my Q70. There is no audio receiver involved (yet). It's still on the floor stand in my master bedroom, and hasn't been mounted to the wall. That HTPC is also using an nVidia GPU, a GT.1030 . I can tell that the colors are all wrong when playing UHD BD. I haven't tried downgrading the desktop to YcbCr420 yet. I don't have a separate UHD 4K BD player hooked up to the TV to compare, also. I do have the built-in streaming apps, though. I own the streaming version of the "Last Jedi" disc in 4K also, and can play it through the built-in Amazon Prime Video app on the TV. Colors look gorgeous with proper colors right off the bat in HDR without having to mess with any TV settings. I'd like to think the Blu-ray disc should look a bit sharper due to the 4x higher bit rate. But when the colors are off, it doesn't really matter how sharp the movie looks :(.

Anyway, I haven't found anything in the Samsung TV menus that shows enough details about the video mode in terms of color depth and color space. I don't have a Marantz receiver in between the HTPC and the TV to play HDMI analyzer. Is there some debug info about the video mode in MC25 I could use to see what it's actually set to ? I would think nVidia might have some sort of log also, but I haven't found that yet. I would need to be able to look at it while MC25 is playing the movie full-screen.
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tij

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Re: UHD 4K Blu-ray disc playing with "8-bit HDR"
« Reply #6 on: June 06, 2020, 11:02:36 pm »

HDR10 is 10bit. The movie you refer to has DolbyVision, which is 12bit. MadVR does not do DV.

I have not tried it in a long while … but from what I remember

1. If you set your desktop to RGB 60Hz 8bit … MC/MadVR was unable to switch to 24/12 … it can only switch to 24/8
2. If you set your desktop to RGB 24/12 … MC/MadVR is able to play 24/12 … and switch to 8 bit when content was 60Hz

One of the reason my desktop is set at 24/12 … downside of course is mouse jumps all over the place.

PS. when using madVR … always use RGB or 4:4:4 … madVR works in RGB space .. if you subsample output to 4:2:0 or 4:2:2 you just throw away MadVR chroma upsampling

PSS. you cannot output RGB or 4:4:4 at 60/12 or 60/10 … not enough bandwidth in HDMI
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madbrain

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Re: UHD 4K Blu-ray disc playing with "8-bit HDR"
« Reply #7 on: June 07, 2020, 12:11:31 am »

HDR10 is 10bit. The movie you refer to has DolbyVision, which is 12bit. MadVR does not do DV.

DV movies are supposed to play in HDR10 on HDR10 displays.

Quote
1. If you set your desktop to RGB 60Hz 8bit … MC/MadVR was unable to switch to 24/12 … it can only switch to 24/8
2. If you set your desktop to RGB 24/12 … MC/MadVR is able to play 24/12 … and switch to 8 bit when content was 60Hz
One of the reason my desktop is set at 24/12 … downside of course is mouse jumps all over the place.

Yes, that's what I have come to find out, MC/MadVR should be smart enough to switch to 4K/24 Hz/RGB 12 bits if desktop is set to 4K/60/RGB 8 bits.
There is enough bandwidth in HDMI for this case. But it doesn't. I would say that's a bug. Perhaps it's "working as designed", but if so, it's very unintuitive.

Even if you set your desktop RGB 24p/RGB 12 bits, what will happen when you play a 60p HDR movie ? Ideal behavior would be to switch to 4K/60p/YCbCr 12 bits.
I tried to play a 60p HDR disc, but AnyDVD couldn't decrypt it so, I don't know what it actually does.
Anyway, given the problems with the mouse pointer at 24 Hz, it isn't a viable solution. You are still in practice forced to change your nVidia control panel settings each time.

Quote
PS. when using madVR … always use RGB or 4:4:4 … madVR works in RGB space .. if you subsample output to 4:2:0 or 4:2:2 you just throw away MadVR chroma upsampling

Why couldn't it pass the disc data's unprocessed ? Isn't it YCbCr anyway ?

Quote
PSS. you cannot output RGB or 4:4:4 at 60/12 or 60/10 … not enough bandwidth in HDMI

Not on HDMI 2.0 devices, anyway. I can on my LG32UD59-B 4K computer monitor which uses DisplayPort. Sadly, it isn't an HDR display :(
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Hendrik

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Re: UHD 4K Blu-ray disc playing with "8-bit HDR"
« Reply #8 on: June 07, 2020, 01:11:27 am »

Why couldn't it pass the disc data's unprocessed ? Isn't it YCbCr anyway ?

A PC always functions in RGB, so no matter what you do, with very rare exceptions, any image will need to be turned into RGB at some point for a PC to display it.
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tij

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Re: UHD 4K Blu-ray disc playing with "8-bit HDR"
« Reply #9 on: June 07, 2020, 02:11:04 am »

I tried to explain in layman terms basics of MadVR

https://yabb.jriver.com/interact/index.php/topic,124136.0.html

Even if you set your desktop RGB 24p/RGB 12 bits, what will happen when you play a 60p HDR movie ? Ideal behavior would be to switch to 4K/60p/YCbCr 12 bits.
I tried to play a 60p HDR disc, but AnyDVD couldn't decrypt it so, I don't know what it actually does.
Anyway, given the problems with the mouse pointer at 24 Hz, it isn't a viable solution. You are still in practice forced to change your nVidia control panel settings each time.

Why couldn't it pass the disc data's unprocessed ? Isn't it YCbCr anyway ?

Setting RGB to 24/12 and playing 60fps movie ... MadVR able to switch to 60/8 and after movie successfully return to 24/12 ... keep in mind i am using NVidia (might be different for ATI)

I suspect this has nothing to do with MC … but rather video driver … sitting initially on 60/8, MadVR might not determine in real time if it can switch to 24/12 or 24/10 (depends on display connected to GPU) ... so it might go for safe 24/8

Mouse for me is not an issue as my PC is sitting in Theatre View and I use remote with no mouse.

If you want to pass video unprocessed … no point in using MadVR … for 4K - you use madVR to upsample chroma and can tone map HDR, which supposedly is much better than what is usually offered by TV/projectors (and imho it is much better)

But if you really want to pass video untouched to TV for processing … if your TV is DLNA render and is connected to network … can choose under [playing now] your TV … then when you play movie, it is send directly to your TV
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Manfred

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Re: UHD 4K Blu-ray disc playing with "8-bit HDR"
« Reply #10 on: June 07, 2020, 08:06:01 am »

10 bit works only if you have the correct settings in madVR/GPU/TV. e.g. my GTX 960 does not support 10 bit at RGB (0-255).
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madbrain

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Re: UHD 4K Blu-ray disc playing with "8-bit HDR"
« Reply #11 on: June 07, 2020, 06:18:45 pm »

10 bit works only if you have the correct settings in madVR/GPU/TV. e.g. my GTX 960 does not support 10 bit at RGB (0-255).

I'm typing this response on my main desktop PC with a GTX 960 . With my LG32UD59-B monitor connected via DisplayPort, I have set 4K/60 Hz /RGB 10-bit in the nVidia control panel. My monitor isn't HDR, though, so it transmitting 10 bits probably doesn't buy me much. Spyder5Pro calibration shows that it has about 80% of 100% of DCI-P3 in 10 bits mode. I should switch to 8 bits and do another calibration to see if the % of DCI-P3 drops any.

On this card and monitor, CTRL-J playing an HDR 24 p movie, Star Wars: last Jedi shows this :
display : 59.99 Hz (10 bit RGB, full)
D3D11 fullscreen windowed (8 bit) <- not sure why it says windowed here, or 8 bits
primaries BT.2020 (says upstream)
HDR 1000 nits, BT.2020 -> DCI-P3

Edit: looks like MC won't switch to 24p on this monitor. Not sure if it's because it's part of a triple monitor setup, or because it just doesn't support 24 Hz. I tried to play with custom modes but didn't have any luck so far.

My HTPCs are using GTX 1050Ti and GTX 1030, though.
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madbrain

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Re: UHD 4K Blu-ray disc playing with "8-bit HDR"
« Reply #12 on: June 07, 2020, 06:35:18 pm »

https://yabb.jriver.com/interact/index.php/topic,124136.0.html

Thanks, I will study this link.

Quote
Setting RGB to 24/12 and playing 60fps movie ... MadVR able to switch to 60/8 and after movie successfully return to 24/12 ... keep in mind i am using NVidia (might be different for ATI)

Thank you. Yes, I have found the same on my HTPC.
Correct me if I'm wrong, but I think the ideal settings on an HDMI 2.0 GPU are :
60/RGB 8 bits for the desktop to have the sharpest text and no laggy mouse movements
24/RGB 12 bits for playing HDR 24p movies
60/YCbCr422 10 bits (or 12 bits) for playing HDR 60p movies

What I'm looking for is a way to achieve all 3 without having to fiddle with the nVidia control panel repeatedly when I play a movie.

Quote
I suspect this has nothing to do with MC … but rather video driver … sitting initially on 60/8, MadVR might not determine in real time if it can switch to 24/12 or 24/10 (depends on display connected to GPU) ... so it might go for safe 24/8

You may be right, I just don't know. Would like a definitive answer on whether the current behavior is forced by the driver and/or OS, or whether it's something MC/MadVR could change, but currently does not.

Quote
Mouse for me is not an issue as my PC is sitting in Theatre View and I use remote with no mouse.

Ah, not the case for me, though. I use other apps.

Quote
If you want to pass video unprocessed … no point in using MadVR … for 4K - you use madVR to upsample chroma and can tone map HDR, which supposedly is much better than what is usually offered by TV/projectors (and imho it is much better)

But if you really want to pass video untouched to TV for processing … if your TV is DLNA render and is connected to network … can choose under [playing now] your TV … then when you play movie, it is send directly to your TV

The display in my home theater is a 4K projector, Optoma UHD65. It only accepts video signals from its HDMI or VGA inputs. There is no DLNA support or smart features of any kind. It isn't networked also. There is an Ethernet jack but it's not for end-users, only service.

The new display in my bedroom is a 4K TV, Samsung Q7DR 82". Not certain whether it supports DLNA or not. I just got it a week ago. I just downloaded the full PDF manual and a search for DLNA didn't find anything.

I think even if it did support DLNA, the Wifi would be the bottleneck in that case to play 4K HDR blu-ray disc. Both the HTPC near and the Samsung TV are using Wifi.
I can play a UHD BR ISO from my NAS over the HDMI out. But if I needed to play it over Wifi, that's twice the bandwidth. It could be up to 200 Mb/s. That's at the upper limit of what I can achieve at the 40 ft distance from the nearest wired Ubiquiti Wifi access point.

Edit: the TV does not show up as a DLNA target under MC.

My old TV does support DLNA, though, but I never used it. I moved it downstairs and it no longer has any device attached to it. I'll try to see if I can play videos from MC onto that TV over DLNA. One of my HTPCs was attached to this TV, but is now attached to the Samsung TV.
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