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Discussion Starter #1 (Edited)


We'll be talking about UHD and answering questions, so if you've got 'em, post 'em here or join the chat room.

On Thursday, May 7, 2015, renowned video calibrators David Mackenzie (left in the photo above) and DeWayne Davis will appear on my Home Theater Geeks podcast. You can watch the show live from 2:00 to 3:00 PM Pacific time at live.twit.tv, and you can join the chat room from that page or at irc.twit.tv, which I'll be monitoring for questions. You can also post questions for DeWayne and David in this thread, and I'll pass along as many as I can during the show.

I hope you can join us for what is sure to be a very interesting conversation!

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Bedroom: 50-in 1080p LCD, XG1v4 (Ultra HD DVR for Comcast), BD Player; Office: 32-in LCD, etc.
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I suppose I could break the ice and ask some "dumb" (and controversial) questions. :grin: (That way, everyone else will feel like they are asking intelligent questions compared to this dummy.)

From what you have seen, have the current crop of UHD TVs, if fed a UHD signal, provided real-world improvements over HDTVs when viewed at typical real-world viewing distances? Or is the improvement only for those who sit closer than normal to their screens?

Since the vast amount of retail HD content tops out at 1080p, do UHD TVs produce better pictures for 1080p content than 1080 HDTVs presented the same 1080p content?

Are UHD TVs providing better calibration controls than premium HDTVs?

Are you starting to see TVs that offer more than just more pixels and, if so, in what areas? And are there sources of such content?

If you were in the market for a TV today, would you purchase a UHD TV today, or wait until standards seem to have been firmed up, interoperability between manufacturers have been demonstrated in retail products (such as between Ultra Blu-ray / UHD set top boxes / Streaming services and UHD TVs), and content are more readily available?

I'm looking forward to watching the show once a link to the YouTube show is posted here in AVSFORUM, whether or not any of my questions get asked. (Hey, if you get better questions or if my questions are totally outside the context of the show, I don't mind if my questions are shipped off to NUL.) Scott, I have yet to see a Home Theater Geeks podcast that I didn't like!
 

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My biggest question is this: How will high dynamic range affect calibration practices across the world? Will there be a divide between the calibrators who prefer to stick to what they know, and calibrators who adopt new practices to deal with UHD's new non-resolution based features. Is this even an issue, or will it be business as usual, just with new gamma and color space parameters?
 

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Have Dave or DeWayne ever calibrated an HDR-capable display?

How is the process different?

With an HDR-capable display like the Samsung JS9500, is it possible to calibrate it to the peak brightness and color space specs recommended for display of HDR-graded content and then use those same settings work for playback of SDR, Rec. 709 content? Or, do you have to use different settings for HDR and SDR-graded content in order to get accurate results from each type of content.
 

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I had my Panasonic 55" VT 60 calibrated nearly 18 months ago. Should there ever be another calibration needed? Does the image degrade over time and how fast? We watch the tv daily and love it so the concern is that if the image is gradually loosing its quality that I will not be aware until it is truly bad.

Thanks,

Mark
 

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Most of my questions have already been asked in the above posts.

Really looking forward to the interview.


m
 

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In the same line of questioning as HockeyoAJB above, do existing colorimeters have the tech to dial in the extended range of brightness in the new HDR specs? Can they accurately calibrate for Rec 2020? Because Rec 2020 doesn't map over 709 in a 1:1 ratio(I'm thinking of Joe Kane's discussion about LUT difficulties), do the meters have to be calibrated or altered in some way to calibrate for that spec? I know this last question is a bit impossible to answer as of yet, but I'm sure somebody out there knows whether this is going to be an issue.

This last one is more HDR direct, but since it's been repeatedly said that peak white in HDR is going to be primarily used for specular highlights, are HDR TVs going to have that 'specular' peak white as a linear part of the grayscale, or is it going to be added to the brightest parts of an image, kind of like frosting on a cake?
 

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Have Dave or DeWayne ever calibrated an HDR-capable display?

How is the process different?

With an HDR-capable display like the Samsung JS9500, is it possible to calibrate it to the peak brightness and color space specs recommended for display of HDR-graded content and then use those same settings work for playback of SDR, Rec. 709 content? Or, do you have to use different settings for HDR and SDR-graded content in order to get accurate results from each type of content.
There was a three hour session led by Kevin Miller and David Mackenzie at Samsung 2015 SUHD TV presentation discussing issues to be aware of when calibrating TVs this year.
http://referencehometheater.com/2015/commentary/samsung-suhd-calibration/
 

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I had my Panasonic 55" VT 60 calibrated nearly 18 months ago. Should there ever be another calibration needed? Does the image degrade over time and how fast? We watch the tv daily and love it so the concern is that if the image is gradually loosing its quality that I will not be aware until it is truly bad.

Thanks,

Mark
Same question for me!


- Joe
 

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Panasonic 85" plasma a good large screen option?

I have a ZT60 and love the picture. I'm wanting something at 80+ screen size but I feel LCDs will disappoint. I noticed on the 2nd hand market a few 85" Panasonic Plasmas are showing up. Will they have a better overall PQ than what I can get today from new LCDs?

I'm not interested in the potential of HDR or 4K, my viewing habits are Blu-Ray and OTA HD.

Thanks!
 

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There was a three hour session led by Kevin Miller and David Mackenzie at Samsung 2015 SUHD TV presentation discussing issues to be aware of when calibrating TVs this year.
http://referencehometheater.com/2015/commentary/samsung-suhd-calibration/
Thanks for the link. That article answers a few of my questions. I particularly appreciated the info given in the following paragraph from the article...

"Now that these displays are out, and hopefully coming for review soon, there will be some differences in the data you see. As a reviewer, I now will have to calibrate each display twice: Once for HDR content, and once for standard HDTV content. Otherwise one will always look off. Hopefully these TVs will be smart enough to automatically switch between an HDR mode and a non-HDR mode when they detect HDR content, but we have to wait for that to appear first."

Does anybody know if the JS9500 is capable of switching between HDR and non-HDR mode automatically (based on content detection/metadata) or do you have to manually adjust a setting or two in order to properly display both types of content?
 

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DeWayne calibrated my Pioneer Elite 60" a number of years ago (a real gentleman--and he did a great job). To my eyes the picture still looks just as stunning as the day he did it.


Like the question above, however, I am curious if there is usually a reason to recalibrate over time. In my case, nothing has really changed in the room since it was initially calibrated.


Looking forward to watching the show.
 

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Thanks for the link. That article answers a few of my questions. I particularly appreciated the info given in the following paragraph from the article...

"Now that these displays are out, and hopefully coming for review soon, there will be some differences in the data you see. As a reviewer, I now will have to calibrate each display twice: Once for HDR content, and once for standard HDTV content. Otherwise one will always look off. Hopefully these TVs will be smart enough to automatically switch between an HDR mode and a non-HDR mode when they detect HDR content, but we have to wait for that to appear first."

Does anybody know if the JS9500 is capable of switching between HDR and non-HDR mode automatically (based on content detection/metadata) or do you have to manually adjust a setting or two in order to properly display both types of content?
When we were at the session (I wrote the article) all HDR content had to be played back over USB because HDMI 2.0 didn't have the HDR header. Now HDMI 2.0a has it, but we're waiting for firmware updates to get that, and devices that can send it. Until those are available, I don't think there is an answer to that question. I certainly hope so, but we'll need the content to come out first.
 

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When we were at the session (I wrote the article) all HDR content had to be played back over USB because HDMI 2.0 didn't have the HDR header. Now HDMI 2.0a has it, but we're waiting for firmware updates to get that, and devices that can send it. Until those are available, I don't think there is an answer to that question. I certainly hope so, but we'll need the content to come out first.
It makes sense that we would have to wait until there's actual HDMI 2.0a source devices to test the display's ability to automatically switch for content sent to the display via. HDMI. However, wouldn't we also want the display to have this capability when fed HDR/non-HDR content via. USB and through a streaming app? IIRC, the display in the Samsung demonstration was calibrated to properly display the HDR-graded content on the USB stick, correct? So, wouldn't it be possible to have tested the auto detection capabilities on that display (at least as far as the USB input is concerned), by plugging in a USB drive with non-HDR rec. 709 content and then comparing the images on the screen with a reference rec. 709 non-HDR display being fed the same content? Naturally, if there was any dynamic range/color gamut "extending/upscaling" turned on then that would have to be disabled first.

I'm guessing you all never had the opportunity to feed the HDR/WCG displays SDR, rec. 709 content to test this?
 

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Some questions:


-- What are the names of all the various HDR formats that are out there for consideration right now?


We have Dolby Vision and SMPTE 2084. Are there any others?


-- Obviously you can only speculate, but how do you predict having multiple HDR formats will play out? Will we see one format become dominant? Will displays and players simply end up supporting them all? Why do we have multiple options in the first place?


-- Could you please explain PQ Gamma? Are there any other proposals for a new gamma standard out there?


-- How's it all going to work in regards to gamma settings? All of our existing HD content has been using standard 2.2 or 2.4 gamma. Will displays and players only switch over to PQ Gamma if there is some sort of flag or metadata in the content to tell it to do so?


- Rob H.
 

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Isn't it heartbreaking there is just not enough time with these Podcasts?

Thoroughly enjoyed it.
 

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Some questions:


-- What are the names of all the various HDR formats that are out there for consideration right now?


We have Dolby Vision and SMPTE 2084. Are there any others?
SMPTE 2084 defines the EOTF, or gamma curve, for HDR. Dolby Vision uses SMPTE 2084 as part of its HDR standard. The HDR standards are mostly using 2084 I believe, and the issue is more packaging of content, metadata, etc...

-- Could you please explain PQ Gamma? Are there any other proposals for a new gamma standard out there?
Gamma was a part of CRT displays, and now it's technically called the Electro-Optical Transfer Function. Gamma controls how quickly to move from black to white. The higher the gamma number the longer you stay in shadows. So in a room that's pitch black, a 2.4 gamma works because there is no light to wash out shadows. In a bright room, you might choose a gamma of 1.8 so that more of that shadow detail is visible over ambient light.

-- How's it all going to work in regards to gamma settings? All of our existing HD content has been using standard 2.2 or 2.4 gamma. Will displays and players only switch over to PQ Gamma if there is some sort of flag or metadata in the content to tell it to do so?
Actually existing HDTV content has no gamma standard. Most production houses use 2.4 is what I've been told, but some might use something else. More and more TVs are shipping with support for the BT.1886 gamma standard which is designed around displays that can't do 100% pure black and to account for that. If you have an OLED, then BT.1886 basically works like a 2.4 gamma.

Rec.2020, which defines UHD, doesn't have a set gamma. Most people expect BT.1886 to be used. For HDR content, SMPTE 2084 comes into play instead, since the gamma curve is very different due to the higher peak light output. If it switches automatically depends on if the TV switches automatically, which is a big "I don't know". I'd assume it will like they do for 3D now, but we will find out for sure.
 

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Is this recorded anywhere?
Think its in the process. Must have been an hour and a half or slightly more.

I thought it was interesting how the professional Panasonic Plasma's were inferior to the consumer displays.


Actually existing HDTV content has no gamma standard. Most production houses use 2.4 is what I've been told, but some might use something else. More and more TVs are shipping with support for the BT.1886 gamma standard which is designed around displays that can't do 100% pure black and to account for that. If you have an OLED, then BT.1886 basically works like a 2.4 gamma.

Rec.2020, which defines UHD, doesn't have a set gamma. Most people expect BT.1886 to be used. For HDR content, SMPTE 2084 comes into play instead, since the gamma curve is very different due to the higher peak light output. If it switches automatically depends on if the TV switches automatically, which is a big "I don't know". I'd assume it will like they do for 3D now, but we will find out for sure.
For the best of consumer displays and professional film industry editing monitors, where does the gamma sit for 5% and 10% grey usually?

What I'm saying is, can any of the displays show shadow detail nicely with a flat gamma of 2.4 at 5% to 10% grey. Or would it always crush? Hence BT.1886.

Isn't OLED gamma different to BT.1886? I thought I read it lower than 2.0 for near black…
 

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For the best of consumer displays and professional film industry editing monitors, where does the gamma sit for 5% and 10% grey usually?

What I'm saying is, can any of the displays show shadow detail nicely with a flat gamma of 2.4 at 5% to 10% grey. Or would it always crush? Hence BT.1886.

Isn't OLED gamma different to BT.1886? I thought I read it lower than 2.0 for near black…
A professional display, properly calibrated, is likely going to measure exactly 2.4 across the whole spectrum. They have displays that do pure black, or close enough to it, for 2.4 across the whole display to work fine. BT.1886 accounts for the fact that most consumer displays don't have a black floor of 0, and assuming they do leads to crushed shadows. On everything I review I target the 1886 curve. On my VT60 plasma, 2.4 and 1886 look almost identical. On an LCD they can look quite different.

OLEDs and other digital displays don't have gamma. CRTs have gamma because they are analog. Give a CRT a 30% stimulus and you don't get 30% of the maximum output, you get something different because of gamma. OLEDs, LCDs, and plasma mimic this with an electrical optical transfer function. It does the same thing, but can be adjusted because of the digital nature of them.

An OLED can do 2.4 just fine in theory. Some show a bit of issues in dark shadows, but that might be the software and not the hardware (it's really impossible to know with only a single vendor). In theory, with a black floor of 0.000, BT.1886 and 2.4 should be identical on an OLED. However, OLED has no inherent gamma, that's just an analog CRT thing.
 
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