Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion.

Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules.

 

Go Back   Doom9's Forum > Hardware & Software > Software players

Reply
 
Thread Tools Search this Thread Display Modes
Old 2nd February 2019, 14:29   #54561  |  Link
Soxbrother
Registered User
 
Join Date: Jun 2017
Posts: 9
New problem : inside Mediaportal, the font size is too big ( windows screen settings is at 150%)
Now when I set it at 100%, everything is as it should be, but now I only hear audio and have no video,
What to do now ?
Soxbrother is offline   Reply With Quote
Old 2nd February 2019, 15:26   #54562  |  Link
Warner306
Registered User
 
Join Date: Dec 2014
Posts: 1,126
Quote:
Originally Posted by j82k View Post
Not sure I'm getting what you're trying to say. Isn't tonemapping only needed because of TVs having a too low peak brightness?
As far as I know mastering monitors don't do any tonemapping, so non-bright scenes should look similar to what I see with dynamic tonemapping disabled.
Then why would it be a good thing to brighten up darker scenes?

I did a small test to see how much LGs dynamic tonemapping messes with non-bright scenes.
I just displayed a 50 nits movie scene in the background while running a grayscale sweep in HCFR.
The result shows exactly what my eyes have been seeing when using LGs dynamic tonemapping. Large deviations from the PQ, even in the lower range. With it turned off it at least follows it nicely up to like 125 nits.
You could be right, but I don't know if your test is accurate. If it is the newest model, it would be less likely the display would be deviating from the curve. Your graph would show raised blacks rather than true black in many scenes because it is lifting the bottom of the curve. That isn't supposed to be the case, unless the display is trying to compensate for poor near black response.

You are somewhat misunderstanding how a static tone curve works. The display will take the static metadata value (usually 1,000 nits mastering peak or 4,000 nits mastering peak) and plot a single tone curve for the entire movie. That curve never changes; it is static, so the entire movie will roll-off the brightness depending on the aggressiveness of the chosen curve. In other words, the whole movie will be slightly darker than intended (tone mapped). There is no relief from this tone curve at any point. The display will follow the PQ curve up to a certain point and add a knee point where the roll-off begins.

A dynamic tone curve will use the source peak as the target for the tone curve, but it will decrease and increase the roll-off as the scene peak changes. So scenes within the brightness of the display (700 nits) can be shown 1:1 with the PQ curve because tone mapping is not required (tone mapping could be disabled or significantly reduced). Scenes that are close to the source peak should look similar to a static tone curve and would use a standard roll-off. The tone mapping roll-off is necessary to present the intended contrast of the scene to make it look HDR when the display lacks the necessary luminance to show all values within its available dynamic range. It is a no-no to go above the PQ curve at any time, but going below the PQ curve is what is considered tone mapping.

I think the area LG needs to improve upon compared to the competition is in blending these changes in brightness. They may be moving the knee point for the tone curve too often or are doing a poor job of fluctuating the roll-off. I haven't heard of any accounts from the reviews I've read of the display boosting the brightness above the PQ curve. The only display that I know does that is the Samsung Q9FN, which consistently boosts 0-100 nits.

madVR is also using a dynamic tone curve with brightness changes, but those changes may be masked better. However, the fluctuations in brightness will be more noticeable when using a range of 0-700 nits than 0-120 nits, so dynamic tone mapping on a bright display can always be capable of some visible shifts in brightness. This is done to keep the image as bright as possible throughout the presentation inline with the original mastered values. No one likes a dark image, so tone mapping compression should be minimized.

Last edited by Warner306; 2nd February 2019 at 16:09.
Warner306 is offline   Reply With Quote
Old 2nd February 2019, 16:40   #54563  |  Link
j82k
Registered User
 
Join Date: Jun 2017
Posts: 145
Quote:
Originally Posted by Warner306 View Post
It is a no-no to go above the PQ curve at any time, but going below the PQ curve is what is considered tone mapping.
But that is exactly what LG's dynamic tonemapping is doing for pretty much any scene that is below the TVs peak brightness. It heavily goes above the PQ curve and that why I think it's crap. It's like what samsung is doing.

And it's not even good at revealing otherwise clipped highlights. MadVR does a much better job at this.
j82k is offline   Reply With Quote
Old 2nd February 2019, 16:45   #54564  |  Link
Warner306
Registered User
 
Join Date: Dec 2014
Posts: 1,126
I don't think this is intended, but it could be doing some monkey business with the source, or you need an HDR calibration. Like I said, the newer the model, the better. Panasonic and Sony are known to be better at this.
Warner306 is offline   Reply With Quote
Old 2nd February 2019, 17:10   #54565  |  Link
chros
Registered User
 
chros's Avatar
 
Join Date: Mar 2002
Posts: 1,505
Quote:
Originally Posted by j82k View Post
I did a small test to see how much LGs dynamic tonemapping messes with non-bright scenes.
Thanks for the graphs! Which LG TV is it?
Quote:
Originally Posted by j82k View Post
I really don't get why people keep praising LG's dynamic tone mapping. It's terrible and I don't ever use it. It behaves almost like a dynamic contrast setting
It seems exactly like the "dynamic contrast" for SDR TVs
__________________
Ryzen 5 2600,Asus Prime b450-Plus,16GB,MSI GTX 1060 Gaming X 6GB(v385.28),Win10 LTSB 1607,MPC-BEx64+LAV+MadVR,Yamaha RX-A870,LG OLED65B8(2160p@23/24/25/29/30/50/59/60Hz)
chros is offline   Reply With Quote
Old 2nd February 2019, 17:45   #54566  |  Link
Alexkral
Registered User
 
Join Date: Oct 2018
Posts: 131
Quote:
A final issue with a lot of displays, specifically home TVs, is the manufacturers deliberately deviating from the HDR specification, in an attempt to generate what they view as 'better' images.

This obviously means the same source footage will be seen very differently on different displays, even if the displays are defined as being 'calibrated'.

However, this issue is actually something we have sympathy for, because as mentioned previously above, the PQ HDR specification is flawed, as the standard is 'absolute', and includes no option to increase the display's light output to overcome surrounding room light levels. The result is that in less than ideal viewing environments, where the surrounding room brightness level is relatively high, the bulk of the HDR image will appear very dark, with shadow detail potentially becoming very difficult to see.

Many home TV manufacturers therefore deliberately 'distort' the PQ HDR EOTF (gamma curve) to attempt to overcome this issue.
https://www.lightillusion.com/uhdtv.html
Alexkral is offline   Reply With Quote
Old 2nd February 2019, 19:11   #54567  |  Link
SamuriHL
Registered User
 
SamuriHL's Avatar
 
Join Date: May 2004
Posts: 4,323
I think Warner306 hit it on the head when you mentioned that LG does not do a good job at moving between scenes. The impact can be very jarring. The latest firmware fixed a little of that and it's a LOT better than it used to be. They're either reacting too quickly to a brightness change or not quickly enough....I don't know which. But the effect in some scenes pulls you right out of the movie you're watching. That is my one gripe with it. Now maybe that's a symptom of what j82k is talking about with LG going above the PQ curve, I don't really know. I doubt the 2018 owners will see much more improvement now that the 2019 models are coming but we can hope.
__________________
HTPC: Windows 10, I9 9900k, RTX 2070 Founder's Edition, Pioneer Elite VSX-LX303, LG C8 65" OLED
SamuriHL is offline   Reply With Quote
Old 2nd February 2019, 20:43   #54568  |  Link
j82k
Registered User
 
Join Date: Jun 2017
Posts: 145
I think it's intentional. People often praise the HDR brightness of LG Oleds compared to other manufacturers, even calling sonys dim. I think the reason for that is that LG intentionally made the PQ curve brighter with dynamic tonemapping (which is enabled by default) to stand out when people compare TVs in the showroom and those who display HDR correctly will look dim in comparison. They probably learned that marketing strategy from samsung.
j82k is offline   Reply With Quote
Old 3rd February 2019, 11:25   #54569  |  Link
chros
Registered User
 
chros's Avatar
 
Join Date: Mar 2002
Posts: 1,505
Quote:
Originally Posted by Alexkral View Post
Thanks, that was really informative! Although I use madVR beta since about 4 months now, I'm still rookie to HDR, e.g. I didn't know:
- absolute vs relative standards (I thought they're all relative)
-- hence viewing environment considarations
-- display device flaws: abl, local dimming
- color gamut volume: 90% of DCI-P3 is basically Rec709

More and more I read about it, I have less intention to replace my current SDR TV.

Quote:
Originally Posted by j82k View Post
They probably learned that marketing strategy from samsung.
__________________
Ryzen 5 2600,Asus Prime b450-Plus,16GB,MSI GTX 1060 Gaming X 6GB(v385.28),Win10 LTSB 1607,MPC-BEx64+LAV+MadVR,Yamaha RX-A870,LG OLED65B8(2160p@23/24/25/29/30/50/59/60Hz)
chros is offline   Reply With Quote
Old 3rd February 2019, 14:17   #54570  |  Link
tp4tissue
Registered User
 
tp4tissue's Avatar
 
Join Date: May 2013
Posts: 408
Quote:
Originally Posted by j82k View Post
I think it's intentional. People often praise the HDR brightness of LG Oleds compared to other manufacturers, even calling sonys dim. I think the reason for that is that LG intentionally made the PQ curve brighter with dynamic tonemapping (which is enabled by default) to stand out when people compare TVs in the showroom and those who display HDR correctly will look dim in comparison. They probably learned that marketing strategy from samsung.
All the k-brands cheat on their cellphone benchmarks, they've stopped that after being caught..

It's up to madvr enthusaists to put a stop to PQ curve cheating. !!
__________________
Ghetto | 2500k 5Ghz
tp4tissue is offline   Reply With Quote
Old 3rd February 2019, 14:28   #54571  |  Link
tp4tissue
Registered User
 
tp4tissue's Avatar
 
Join Date: May 2013
Posts: 408
Quote:
Originally Posted by Warner306 View Post
I don't think this is intended, but it could be doing some monkey business with the source, or you need an HDR calibration. Like I said, the newer the model, the better. Panasonic and Sony are known to be better at this.
Is there a way to calibrate through madtpg for use with the HDR tone-mapping function ?

I noticed going through dispcal, the calibration for rec2020 will not slot into the normal calibration page, and only works for the hdr tone-map page.
__________________
Ghetto | 2500k 5Ghz
tp4tissue is offline   Reply With Quote
Old 3rd February 2019, 17:23   #54572  |  Link
Warner306
Registered User
 
Join Date: Dec 2014
Posts: 1,126
Quote:
Originally Posted by Alexkral View Post
A final issue with a lot of displays, specifically home TVs, is the manufacturers deliberately deviating from the HDR specification, in an attempt to generate what they view as 'better' images.

Many home TV manufacturers therefore deliberately 'distort' the PQ HDR EOTF (gamma curve) to attempt to overcome this issue.

https://www.lightillusion.com/uhdtv.html
This is one of the early articles released when HDR was introduced. I think it is less common to artificially brighten HDR content since calibrators have made TV manufacturers more conscious of properly following the PQ curve. Consumers are also becoming more educated about PQ HDR content.

Brightening the PQ curve does come with drawbacks. All HDR video games include a brightness slider to increase the brightness of HDR games. However, this raises the value for reference white, which comes at the expense of making the blacks more grey in dark scenes. The 2017 LG OLEDs suffered from this issue, which was corrected in the 2018 models. I don't know if the 2018 models are doing any other manipulation of the PQ curve, but it doesn't really make sense to have a dynamic tone curve that is constantly fluctuating above and below the PQ curve without distorting the image. Samsung uses a static curve with its QLEDs, but it is either rising from black more slowly or compensating for the brighter 0-100 nits by using more aggressive local dimming. I'm sure even Samsung will do away with this when dynamic tone mapping is added.

You don't really want to brighten images with absolute brightness values because the image can become washed out if pushed too far.

Last edited by Warner306; 3rd February 2019 at 17:28.
Warner306 is offline   Reply With Quote
Old 3rd February 2019, 17:27   #54573  |  Link
Warner306
Registered User
 
Join Date: Dec 2014
Posts: 1,126
Quote:
Originally Posted by tp4tissue View Post
Is there a way to calibrate through madtpg for use with the HDR tone-mapping function ?

I noticed going through dispcal, the calibration for rec2020 will not slot into the normal calibration page, and only works for the hdr tone-map page.
You can create an SDR 3D LUT if you output in an SDR format. But you can't use a 3D LUT with pixel shader when outputting in an HDR format. You would have to choose to tone map by 3D LUT and make a few static tone curves: 500 nits, 1,000 nits, 1,500 nits and 4,000 nits to replace the display's internal static curves. This could be accomplished with a few profile rules under hdr.
Warner306 is offline   Reply With Quote
Old 3rd February 2019, 19:09   #54574  |  Link
Plutotype
Registered User
 
Join Date: Apr 2010
Posts: 234
Hi folks,
Will madvr support HDR10+ dynamic metadata decode or passthrough?
Thanks
__________________
__________________
System: Intel Core i5-6500, 8GB RAM, GTX960/GTX1060, 55" Sony Bravia KDL-55HX850 @ 1920x1080 24p, Yamaha YSR-1100 surround bar
Setup: Win7/Win10 Pro, madvr/JRiver 24
Plutotype is offline   Reply With Quote
Old 3rd February 2019, 22:05   #54575  |  Link
Alexkral
Registered User
 
Join Date: Oct 2018
Posts: 131
Quote:
Originally Posted by Plutotype View Post
Hi folks,
Will madvr support HDR10+ dynamic metadata decode or passthrough?
Thanks
That depends on LAV filters first.

Quote:
Originally Posted by Warner306 View Post
This is one of the early articles released when HDR was introduced.
The problem with HDR being too dark is still there though. 100 nits for diffuse white is too low in not ideal conditions (I'd say it's even too low in ideal conditions but that's just my oppinion) compared to where most people is used to see it in SDR. ITU-R BT.2408-0 recommends diffuse white = 203 nits for PQ and HLG production on a 1000 nits peak luminance display. Another study in the same report suggests diffuse white at 140 nits for indoor scenes and 425 nits for outdoor scenes, for PQ with 4000 nits peak luminance. I think I have read somewhere that at least some titles now are being graded with diffuse white at 203 nits. This should be the best way to solve this. We loose 1 stop at highlights but the overall brightness match better with SDR.

Quote:
Originally Posted by Warner306 View Post
it doesn't really make sense to have a dynamic tone curve that is constantly fluctuating above and below the PQ curve without distorting the image.
If I'm not wrong, both SMPTE ST 2094-10 (Dolby Vision) and SMPTE ST 2094-40 (HDR10+) curves change dynamically the knee point in a similar way that what Soulnight's utility with dynamic target nits is doing now with the BT.2390 EETF.

Last edited by Alexkral; 3rd February 2019 at 22:10.
Alexkral is offline   Reply With Quote
Old 3rd February 2019, 22:37   #54576  |  Link
tp4tissue
Registered User
 
tp4tissue's Avatar
 
Join Date: May 2013
Posts: 408
Quote:
Originally Posted by Warner306 View Post
You can create an SDR 3D LUT if you output in an SDR format. But you can't use a 3D LUT with pixel shader when outputting in an HDR format. You would have to choose to tone map by 3D LUT and make a few static tone curves: 500 nits, 1,000 nits, 1,500 nits and 4,000 nits to replace the display's internal static curves. This could be accomplished with a few profile rules under hdr.
Yea, that's what I meant, create an HDR 3Dlut, but ONTOP of Dynamic Tonemapping, output HDR.

Do you know if this feature will be added in the future ?

Seems to be straightforward, is there a specific hitch that it's not already possible ?
__________________
Ghetto | 2500k 5Ghz
tp4tissue is offline   Reply With Quote
Old 3rd February 2019, 23:05   #54577  |  Link
70MM
X Cinema Projectionist NZ
 
Join Date: Feb 2006
Location: Auckland NZ
Posts: 280
Ive tried error diffusion 1 and 2 for dithering in madvr and I cant see any obvious differance between them. Im upscaling BDs to 4K and displaying on a large 145" curved screen with a JVC NX9 4K projector. Since I dont know which is best as I see nothing, which might be the prefered option in my case producing the less artifacts? Thanks in advance...
70MM is offline   Reply With Quote
Old 3rd February 2019, 23:08   #54578  |  Link
huhn
Registered User
 
Join Date: Oct 2012
Posts: 5,964
the default ordered dithering
huhn is offline   Reply With Quote
Old 3rd February 2019, 23:39   #54579  |  Link
70MM
X Cinema Projectionist NZ
 
Join Date: Feb 2006
Location: Auckland NZ
Posts: 280
Quote:
Originally Posted by huhn View Post
the default ordered dithering
Can you explain to me please huhn why ordered dithering is better than error diffusion 1 & 2 please? Thank you kindly for helping...
70MM is offline   Reply With Quote
Old 4th February 2019, 00:05   #54580  |  Link
SamuriHL
Registered User
 
SamuriHL's Avatar
 
Join Date: May 2004
Posts: 4,323
He's not saying it is. But if you don't SEE a difference, there is a HUGE difference in performance between ordered and error diffusion and there's no sense killing performance for something you can't see.
__________________
HTPC: Windows 10, I9 9900k, RTX 2070 Founder's Edition, Pioneer Elite VSX-LX303, LG C8 65" OLED
SamuriHL is offline   Reply With Quote
Reply

Tags
direct compute, dithering, error diffusion, madvr, ngu, nnedi3, quality, renderer, scaling, uhd upscaling, upsampling

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 22:43.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.