HDR Discussion Thread

[bruceames]

A place for discussing HDR10, Dolby Vision, how they compare, info articles, why you love it or hate it, and everything HDR.

A few info articles on HDR:

What HDR Means for Color and Luminance

https://www.avforums.com/article/ult...ces-2016.12295

[legends of beyond]

Originally Posted by bruceames.

The place for discussing HDR10, Dolby Vision, how they compare, info articles, why you love it or hate it, and everything HDR.

here's an article to get the ball rolling.
What HDR Means for Color and Luminance

I really love UHD, I think it's better than 4K. I hate it when they uses it for an artificial pop though. For non- native HDR films, just give it more air to breathe.

[zhu8808]

Sony X930D SDR vs HDR

[pawel86ck]

Home comparisons on uncalibrated displays suggests wrong ideas when it comes to HDR (because it looks like HDR is too dark, while SDR overblown).

Here's some great article about HDR that would not confuse people

http://www.lightillusion.com/uhdtv.html

And picture comparison SDR vs HDR on calibrated HDTV's. As anyone can see, on calibrated displays average brightness levels looks similar (not like in these "home" comparisons).

http://www.hdtvtest.co.uk/news/4k-vs-201604104279.htm

[katiehlvr2]

Originally Posted by pawel86ck

Home comparisons on uncalibrated displays suggests wrong ideas when it comes to HDR (because it looks like HDR is too dark, while SDR overblown).

Here's some great article about HDR that would not confuse people

http://www.lightillusion.com/uhdtv.html


And picture comparison SDR vs HDR on calibrated HDTV's. As anyone can see, on calibrated displays average brightness levels looks similar (not like in these "home" comparisons).

http://www.hdtvtest.co.uk/news/4k-vs-201604104279.htm

Those pictures posted above show me just as much as the pictures do in your link. Calibrated or not.

[Penton-Man]

Originally Posted by bruceames.

HDR discussion thread.

The place....

“The place”.
I don’t know Bruce, that sounds rather presumptuous to me, I might have to consider waiting for The Official HDR Discussion Thread.

[Penton-Man]

Originally Posted by pawel86ck

Here's some great article about HDR that would not confuse people

http://www.lightillusion.com/uhdtv.html

Since you brought up the reference again, I beg to differ, unless in the interim, the author has made corrections.

[surami]

May I ask somebody to watch my 4K UHD HDR BT.2020 ST.2084 encoded footage on a 4K HDR TV (USB)? Please report back, how it looks?

[ray0414]

Originally Posted by surami

May I ask somebody to watch my 4K UHD HDR BT.2020 ST.2084 encoded footage on a 4K HDR TV (USB)? Please report back, how it looks?

i downloaded the video, but wont be able to watch it til a later time.

downloaded Jamess' new videos too, will also watch later.

[pawel86ck]

Originally Posted by katiehlvr2

Those pictures posted above show me just as much as the pictures do in your link. Calibrated or not.

"zhu8808" comparsion shows pictures with different brightness levels. HDTVtestcouk article is supplied with pictures on calibrated displays, and as you can see, brigtness is comparable

Here's how it should looks like

http://www.hdtvtest.co.uk/image/arti...ight-large.jpg
http://www.hdtvtest.co.uk/image/arti...ax-3-large.jpg

And below BD vs UHD comparison on uncalibrated displays, and you can clearly see the difference in brightness levels
http://www.hdtvtest.co.uk/image/arti...ax-2-large.jpg
http://s16.postimg.org/gsaciz9rn/Clipboard01ass.jpg

[James Freeman]

What we must understand is that most film shot on camera still use 18% output as middle grey in mind.
Middle grey is 50% input (128 in 8bit) that will give you 18 nit (cd/m2) output.
Who determined that 50% input is 18 nit output? 100 nit peak Gamma 2.4 CRT TV!
So the whole system is still adapted to SDR CRT technology with Gamma of around 2.4.

The camera (digital or film) may capture huge dynamic range but the captured middle grey card should still produce around 18 nit on your SDR or HDR display!

A calibrated SDR TV (100nit peak) and HDR TV (1000nit peak) have the same picture luminance and information from 0 to around 50 nit and SHOULD look the same.
75% input (190 in 8bit) for that matter is 50 nit on a CRT or any SDR TV.
It's from 50 nit and up what makes the difference between SDR and HDR TV.

On an SDR TV the huge dynamic range highlights are compressed from 50nit to 100nit with something called Log curve in the camera (film does that naturally).
While on HDR TV the highlight have much more room from 50nit to 1000nit so the highlights are not as compressed, in fact they have to be expanded from the camera Log curve.

The Light Illusion site has a terrible example.
His error is that he thinks the luminance is totally clipped above 100nit from the camera capture (like the HDR to SDR images blu-ray.com posted).
In reality all the F-Stops the camera captured are compressed from 50nit to 100nit (75% input to 100% input) or 190 to 255 in 8bit.
For HDR, 18 nit and 50 nit are STILL the same as SDR but above 50 nit, luminance is simply expanded and mapped.

In other words, from 50 to 1,000nit the captured data above 50nit has to be expanded linearly and mapped to input levels 44% to 75% in ST.2084.
Whether on SDR, from 50 to 100nit output is 75% to 100% input.

As a side note, modern cameras can capture around 14 F-Stops or 16,384:1 contrast ratio (that is A LOT).
An HDR TV can easily reproduce that (1,000/0.01 nit) = 100,000:1.
In fact, the last generation plasma TVs can do 20,000:1 no problem, so they can also show all the dynamic range the camera captured.

A little technical, but that will answer few questions.

[Deciazulado]

Originally Posted by James Freeman

The Light Illusion site has a terrible example.
His error is that he thinks the luminance is totally clipped above 100nit from the camera capture (like the HDR to SDR images blu-ray.com posted)

Note: The screenies were from 300nits up as that's the middle ground between "old" 100nit TVs and "new" 1000nit TVs.

[bruceames]

Interesting comment regarding the difference between DV and HDR10.

Even Dolby in its latest presentations points to the biggest advantage of its dynamic metadata being for lower-end TVs. Netflix says the same. For this article I also talked to Joel Barsotti, head of advanced color research at Spectracal, who had a good summation: "The closer the TV's capabilities are to those of the original mastering display, the less difference we see between HDR10 and Dolby Vision."

http://calman.spectracal.com/hdr.html

Another point to be made: HDR10 is the standard, not Dolby Vision. In fact, HDR10 comes from Dolby Vision and is just the base layer. So technically there is no format war. The DV enhancements mainly pertain to improving the picture on lower end displays. The probable reason why Sony or Samsung didn't include DV in their 2016 models is because it wasn't necessary. In high end models, HDR10=DV. It's no coincidence that DV is being implemented in the lower end models (LG and Vizio) and HDR10 in the higher end models (Sony and Samsung). The only exception is LG OLED, but then DV is desirable because even though OLED has an infinite contrast ratio, the peak brightness is only around 500 nits. So if the content is mastered at 1000 nits, then the dynamic metadata will scale the content accordingly.

[2themax]

HDR10=DV isn't always true. 10bit 4:2:0 != 12bit 4:2:2.

[bruceames]

Originally Posted by 2themax

HDR10=DV isn't always true. 10bit 4:2:0 != 12bit 4:2:2.

Yes, when there are 12 bit consumer TVs available then DV will be superior. But today there is no real difference between them as long as you have a high end display since DV content has to be scaled down to HDR10 levels anyway.

[Stevenn1992]

Can any of you answer which is the better option and why.

A. 4KOLED without HDR
or
B. 4K-LED with HDR

[Penton-Man]

Originally Posted by bruceames.

A place...

I like the editing change in phraseology of your first post from “the” place to “a” place.

Originally Posted by bruceames.

A few info articles on HDR:
What HDR Means for Color and Luminance

In short, the ‘colorfulness’ of a given color can be increased when its
luminance is increased. This is known as the Hunt Effect which I’ve made reference to in at least one old posting (use search word 'Hunt'). As far as your link to the article from Sound and Vision with the lead-in pic, it’s good to see an AV journalist finally using color volume as a descriptor.

Originally Posted by bruceames.

and everything HDR.

How the Ultra HD Alliance is involved

[Penton-Man]

Originally Posted by bruceames.

Interesting comment regarding the difference between DV and HDR10.
http://calman.spectracal.com/hdr.html

Be it HDR10, or Dolby Vision something that goes unrecognized or at least underappreciated is the source, for even if you have access to the original camera negative or the RAW files from which you’re planning to produce an HDR version the quality of the cinematography is of paramount importance, arguably more important than choosing HDR10 or Dolby Vision for mastering. Over time I think that AV bloggers will pick up on the significance of what I said last January.

thick negative = a well exposed image containing a full tonal image…in other words, a solid picture to work with, in that the whites aren’t clipped and the blacks aren’t crushed. Colorists and post production supervisors having experience in HDR mastering are finding out that not all movies are great HDR candidates.

DPs having an interest in HDR versions for their future work…. take note ^. Some already have, like at NAB 2016 this past week.

[bruceames]

Good point Penton about needing 10 bit HDR to really appreciate the WCG more. HDR by itself is much more impressive than a WCG by itself, but perhaps here the sum is greater than the parts? (just guessing with that last part, you're the expert here )

[ray0414]

Originally Posted by Stevenn1992

Can any of you answer which is the better option and why.

A. 4KOLED without HDR
or
B. 4K-LED with HDR

All 4k oleds have hdr . So I'm not sure what you mean.