High Dynamic Range - HDR in Layman's Terms

[mechman]

HDR or High-Dynamic Range came shortly after the huge influx of HDTVs became common in most people’s living rooms or theaters. It replaces what most everyone is currently using which is the Standard-Dynamic Range (SDR) video display. It adds more depth creating what most folks consider an almost 3D look to the image and it matches more closely with what we see in the real world. Improvements made are to shadow detail and brightness detail across the whole color gamut. Everyone talks about 4K or Ultra High Definition TV (UHDTV) as being one of recent improvements to display. And while that’s true in a sense, the benefits are much less when it’s not implemented with HDR.

Displays up until recently have all been based upon Rec709 (BT.709) and Rec601 (BT.601) color spaces. These color spaces only contain a fraction of the visible color values or chromaticity. The newer color spaces under HDR, which include both DCI-P3 and Rec2020 (BT.2020), produce roughly half of the colors under the visible color values. Here's an image I found from an Italian magazine that depicts the gamuts nicely:

HDR gamuts with REC709

• mechman
• Jul 15, 2017

Rec2020 gamut vs DCI-P3 gamut vs Rec709 gamut

The outer green triangle is Rec2020 (Dolby Vision), the inner red triangle is DCI-P3 (HDR10) and the inner white triangle is Rec709 or the current standard. As of this writing, there are no displays that are Rec2020 capable. Rec2020 displays are slated to roll out in 2020.

Contrast ratio is another improvement made with the advent of HDR. HDR badged sets must be able to produce a range of brightness and darkness compatible within the particular standards they support. Ideally the contrast ratio would be 10,000nits to 0nits. Currently though LED/LCD displays produce a range of 1100nits to .05nits with OLED technology producing 540nits to .0005nits. Needless to say, that's quite an improvement in contrast ratio over older displays.

So what you will see in the future to come is a greater dynamic range and a much improved color depth.

There are currently five different standards for HDR floating around.

Dolby Vision

If you read Todd’s review of the 2017 TV Shootout, you saw where he mentioned that Dolby Cinema content is mastered on the big screen. Normally, content is mastered in studio on a monitor such as the Sony BVM-X300 that was on display at the shootout. Dolby Vision uses the REC2020 color standard which is slightly larger than the HDR10 (DCI-P3) format. This is a proprietary format mastered under Dolby’s higher standards at a higher cost. While I have been out of the loop for a few years, it’s my understanding that there isn’t a lot of Dolby Vision content available at this time outside of some Netflix and VUDU content. And not all manufacturers have not all yet incorporated it into their models. I believe it’s currently limited to LG OLEDs and some current Vizio models. There are a few Dolby Vision discs on the market right now including Despicable Me and Despicable Me 2.

Dolby Vision allows up to 12 bit color or 68.7 billion colors. Bit depth is basically color depth or the gradation of colors. With 12 bit color, each pixel has 12 bits of data per color or 212 or 8,192 variations of each color.

HDR10

HDR10 is an open source format that any manufacturer can implement into their display at no cost. It is most widespread as well. All HDR Blu-ray discs are currently HDR10 discs. There is also content on Netflix and Amazon Video. HDR10 utilizes the smaller DCI-P3 gamut at 10 bit color depth - 10 bit color or 210 = 1024 variations of each color. HDR10 incorporates static metadata that is set at the start of the content and doesn't change throughout.

HDR10+

HDR10+ was announced this last spring by both Samsung and Amazon. HDR10+ improves upon HDR10 by adding dynamic metadata encoded within the scenes to compete more closely with Dolby Vision. It adjusts the brightness or darkness of scenes on a frame by frame basis. Amazon plans on introducing HDR10+ content later this year.

HLG

HLG stands for Hybrid Log-Gamma. It is being developed by NHK and the BBC to serve as the live video format. It is royalty free and backwards compatible with SDR displays. YouTube supports this format. This format will be independent of metadata.

Advanced HDR

Advanced HDR is being formatted for broadcast TV and for upscaling SDR content to HDR. The intent is for this format to be cross platform. Which means that it should work with any of the other standards' hardware and it will be easier to implement


Whether or not you think you should adapt to HDR or not will be your own personal preference. The main thing that you should keep in mind is that Dolby Vision will play on an HDR set and neither HLG nor Advanced HDR will require you to buy new hardware. The formats are cross compatible. Some of what I have learned over the last week or so is that HDR is not implemented equally and also that it can be finicky as well. Regardless, hopefully this will help you when decision time draws near.

 

[Sonnie Parker]

Excellent info Steve. This is no doubt going to be an important feature on all future displays and projectors. I do agree is does not appear to be consistent, which actually causes some of it to not look real... or make some shows soap opera-ish looking.

 

[mechman]

Soap opera-ish looking? That sounds like some other issue. Todd will probably know better than I cause I'm still getting caught up, but usually that's some sort of interpolation type of filter that needs to be disabled.

 

[Tonto]

Wow Sonnie, I had no idea you were a "Soap Opera" watcher!

 

[Todd Anderson]

Soap opera-ish looking? That sounds like some other issue. Todd will probably know better than I cause I'm still getting caught up, but usually that's some sort of interpolation type of filter that needs to be disabled.

The cause of the soap opera effect?

 

[mechman]

The cause of the soap opera effect?

Yeah I would guess it's some sort of motion interpolation filter that needs to be shut off. Sound about right?

 

[Todd Anderson]

Yes. Soap Opera Effect comes from frame interpolation, which is referred to by manufacturers in a number of different ways. You'll see it called clear motion drive... true motion... that kind of thing.

LCD manufacturers use it to help smooth out fast motion content (such as an ice hockey game) where the screen's native refresh rate creates a blur. It's a process of inserting frames before and after frames, thus creating a more stable looking image. We're actually seeing it on OLEDs too (wasn't as common – if present at all – on plasma displays... perhaps very late model Panasonic TVs shipped with it, but I don't believe so).

Once your eye sees the effect, you can't unsee it. I'm very sensitive to it, even on its lowest setting. To me it's annoyance that should be turned off immediately. However, some folks like it (in fact, one of the judges at the TV Shootout admitted that he has it engaged on his Sony LCD).

For me, tho, it's very unnaturally and floaty looking (all most too realistic...much like Sonnie's soap operas! ).

The problem is that manufacturers ship TVs with it engaged. I would assume that shipping with it "on" is a reaction to customer complaints about motion blur. A lot of folks probably don't know this, but many HDTVs were (and possibly currently are) shipped with 1:1 pixel model disengaged (which results in a loss of resolution)... the reason? Because it hides the little close-captioning flutter that can be seen on some television channels... manufacturers were fielding service calls because TVs had funny black dots dancing along the top of the screen, so they started shipping out of 1:1 to solve the problem.

 

[Peter Loeser]

I'm very sensitive to it, even on its lowest setting. To me it's annoyance that should be turned off immediately

Same. I hate it. Seems most people know either don't notice, don't know how to turn it off, or don't mind it. Drives me nuts. Any chance I get when nobody is looking I disable it. No one has complained yet

Back on topic - thanks for the great summary Steve. I've got this one bookmarked for reference.

 

[Todd Anderson]

I think a lot of people don't know what they're seeing - but know something is off. I've had a few friends complain about their TVs... once that's off, they're happier.

And, agree! Nice summary Steve! :-)

 

[Sonnie Parker]

I have CMD turned off, but there are some shows that still don't really look right with HDR, it's just too much of a good thing I guess.

 

[Todd Anderson]

Is that on your Vizio?

Some TVs turn it on automatically when switching from SDR to HDR. The LG C6 (I think) did it at last year's TV Shootout and the Samsung was doing it at this year's Shootout. It's a firmware issue.

 

[Sonnie Parker]

I haven't really tried it on the Vizio... just the JVC. It turns on and off automatically on the JVC, but some scenes look over saturated and some look way too dark, just depends on what I am watching. Then other times it looks great.

 

[Todd Anderson]

The problem with projectors is that they're putting out 200 to 250 nits (I'm guessing... but probably accurate), while most HDR movies are graded for about 1000 nits (the very VERY best TVs display about 1000 to 1700 nits). To add to the confusion, there's no reference brightness levels set for UHD Blu-ray standards.

You can see how things get very confusing for the video chain (and ultimately what is seen).

As for you Clear Motion Drive: you need to turn it off for every lens mode. So, turn it off for Cinema... then switch over to HDR mode and turn it off there too. That should stop it from happening (that was the fix on my end).

Have you tried these settings for HDR:
http://www3.jvckenwood.com/english/...0r_xc6890r_xc5890r_rs600_rs500_rs400_uhd.html

 

[mechman]

That's what I was really wondering, whether it was something to do with HDR or not.

 

[Todd Anderson]

No... it's not inherently due to HDR. It can also be matched to SDR. But, for whatever reasons, TV manufacturers like to force it on (for some models) when HDR gets engaged. Most have corrected this issue with firmware (keeping user presets intact)...but some have not.

Super annoying!

 

[Sonnie Parker]

I don't know that I have turned it off for all modes... I will check that tonight.

I have not tried those settings either, but I will do that as well.

 

[Todd Anderson]

Definitely turn it off for HDR and Cinema. Once you do, it should never automatically re-appear.

(I wouldn't be surprised if your Vizio has it engaged out of the box, too)