Ultimate Guide to High Dynamic Range (HDR) in 4K TVs – Contrast, Wide Color Gamut, HDR Display and the Latest HDR Content
So what does HDR display quality in 2016 really depend on? Well, we think it revolves around several key things: high dynamic range, Color, contrast and the standards that are being developed for all of these by different companies. This is the technology that’s now garnering even more attention from both consumers and manufacturers than even 4K resolution itself, and we’re going to cover it in detail below.
Now, without further ado, let’s take a closer look at what all these technologies mean and how you can select for their best features in your 4K UHD TV.
What is High Dynamic Range?
In very basic terms, HDR is the ability to expand the different stops of both bright and dark levels in a 4K TV for a wider, richer range of colors, much brighter, more realistic whites and much deeper, richer darks, all being manifested at the same time on the same display as needed. With this, a TV display takes on a more “dynamic” look and ultimately gives the content a viewer is looking at a far more vibrant and realistic appearance.
HDR furthermore also preserves detail in content in ways that SDR (standard dynamic range) can’t, with finer visual and color characteristics in both the brightest and darkest area of a picture being kept while colors in general look more natural and displayed scenes closer to how they’d appear when viewed directly by the naked eye.
What this means is that contrast and color are the two pillars of HDR technology and the new development in 4K TVs is aimed squarely at enhancing both to the maximum possible degree. Of course, there are many standards and mechanisms for how this should be done, and we’ll get to their finer points shortly but for now, a fundamental search for high quality HDR means expanding the quantity of nits (a unit of brightness) in bright content while decreasing them to the minimum possible degree in the darkest content. At the same time, color in 4K TVs should be expanded dramatically for the sake of enhancing HDR display still further.
Currently, the “ideal” HDR standard that key players are pushing for would involve a dynamic range of 0 to 10,000 nits, which would really bring 4K TVs close to what real life looks like (the sky on a sunny day offers about 30,000 nits of brightness to the naked eye). However, in practical reality, even the latest HDR standards for premium 4K ultra HD TVs cover only 0.05 to 1100 nits, with a standard of 0.0005 nits to 540 nits of brightness in the dimmer technology of OLED 4K TVs.
Thus, as you can see, this technology has plenty of room for improvement left in it, even if it’s already starting to look very good in the latest 4K HDR TV models on sale from 2015 and for 2016.
Does HDR have more importance than 4K resolution in Display?
The answer to this question is an unequivocal yes. You’ll note that all discussions of HDR technology today revolve around the technology working in 4K TVs. The reason for this is simple enough –high dynamic range is currently only offered and being developed commercially in the cutting edge of TV display and that lies strictly in the 4K and ultra HD resolution end of the television spectrum. Furthermore, all those extra pixels of 4K ultra HD display certainly help in creating a generally sharper, crisper image quality in a TV.
However, between the two display technologies, HDR is definitely the more visible and immediately notable spec with much more room for development and refinement left in it. A 4K TV can only ever have a maximum of 8.29 to 9 million pixels in it (depending on how you specifically define 4K resolution) and larger resolution technologies will likely take a while to develop due to their massive data requirements and will in any case not go beyond 8K resolution for the foreseeable future. High dynamic range on the other hand is still just in its infancy and even for the short term –the next couple of years—has a vast amount of development left to it as specific brightness levels are incrementally raised until they emulate reality and colors are also enhanced to a much greater degree of precision.
Furthermore, within the ranges of specific technologies that surround and make up the color and contrast specs in HDR, there are enormous variations of specs and functionality which can be tweaked.
Most importantly however, high quality HDR is simply so much more notable in any TV display when activated. While many viewers might have a hard time distinguishing an HD resolution from a 4K UHD resolution in a small to mid-sized 4K TV at normal viewing distances, high dynamic range in a 4K TV looks much more obviously better than standard dynamic range in any side-by-side comparison.
What makes a TV into an HDR display?
A 4K TV can’t just be an HDR television because it has a bright picture. There are actually highly specific specs behind the technology and there are also even different “levels” of HDR technology that can be applied to genuinely HDR-capable 4K TVs.
This slight confusion alone has actually caused some companies, like Samsung in particular in our experience, to claim that HDR exists in certain models without those TVs actually having more than very good SDR brightness and dark tone capacity or more than the basic hardware connectivity for the technology built into them. In 2015 it was not so loosely implied by Samsung that their JU-Series 4K televisions like the JU7100 and JU7500 were HDR models when in fact they are not. Only Samsung’s SUHD TVs offered genuine HDR of some type or another.
- Shifting HDR Standards
Furthermore, since “levels” of high dynamic range power even among genuinely HDR TVs on the market exist, not all HDR labels are created equal. Thus, several 4K UHD TVs from 2015 had the necessary brightness, dark levels and other technologies to be called HDR TVs by their manufacturers. These included Sony’s 2015 X850C, X900C, X930C and X940C 4K Bravia TVs. They also included Samsung’s SUHD JS9500, JS9000 and JS8500 4K models. However, in 2016 a whole new HDR standard called “UHD Premium” (more on this below) emerged from the UHD Alliance (of which all of these companies are binding members) and according to its exacting specs, HDR as it had been known in virtually all of these 2015 TVs was no longer good enough.
Thus, in 2016, “UHD Premium” HDR 4K TVs only consist of the 2015 Samsung and Sony flagship televisions, the SUHD JS9500 and the Sony XBR-X940C, and in the entire 2016 lines of SUHD and top-shelf 4K TVs from both companies. These would be the Samsung KS-Series SUHD models and Sony’s XBR-XD Series 2016 Bravia 4K TVs like the X850D, X900D and X940D.
- HDR in OLED 4K TVs
Then there are LG’s OLED 4K TV models. The “UHD Premium” specs apply slightly differently to them, with much lower standards for peak brightness due to the inherent dimness of OLED technology and with these models, maybe only one, the late 2015 EF9500 could be considered an HDR OLED model, with only the 2016 OLED Signature G6 4K TV being a truly HDR OLED model.
Furthermore, we have other brands that produced no HDR 4K models in 2015 but are now following the “UHD Premium” or Dolby Vision standards for high dynamic range to create what they call real HDR 4K televisions for 2016. These brands include Hisense, TCL, Panasonic and others. Finally, there are also Vizio’s 4K UHD televisions, of which only two from 2015, the Reference Series, offered real HDR.
- HDR Battles
Vizio however is in active dispute with the standards of the UHD Alliance and instead claims that the Dolby Vision specs for high dynamic range in its Reference Series 4K TVs are what provides superior HDR technology. The company’s 2016 P-Series 4K TVs all claim to have HDR but of the Dolby Vision kind, which does not depend on the new connectivity spec of HDMI 2.0a to move 4K UHD content with HDR encoding into a 4K TV. LG’s OLED 4K TVs, TCL’s 4K TVs and content sources from companies like Roku and TCL will all also support Dolby Vision HDR, without the need for HDMI 2.0a.
In contrast, all of the other 4K HDR TV models above do offer HDMI 2.0a as a key connectivity spec for the sake of their HDR capabilities.
So in summary, while the situation is confusing as far as which type of HDR goes for which 4K TV and how good the different HDR specs are. The bottom line is that 2016 4K TVs will for the most part all come with high dynamic range of some type or another.
The Two Pillars of High Dynamic Range
Aside from the confusion described above for the HDR landscape in TV display, we can definitely say that there are two core pillars of this technology which will be carefully implemented in all HDR standards. They are the following:
Though HDR is about more than just contrast, this is one of the most important components of and HDR display system and refers to the difference between light and dark scenes in terms of brightness and its opposite. The greater the range of contrast, the greater the quality of high dynamic range as well.
With contrast, the ideal development is one in which an extremely bright bit of imagery can be placed next to an extremely dark piece of display space without any bleeding through of light occurring in the dark spots. OLED 4K TVs master this almost perfectly but can maintain only limited maximum brightness levels, normally no more than 600 nits, while LCD TVs can manage very high brightness of 1000 nits or more but also fail to completely eliminate minor amounts of light bleed-through in the dark sections of a screen.
In either case above, TV makers are faced with a dilemma if they want to call their TV an HDR model because the maximum brightness of a TV in nits has to be matched by a certain simultaneous level of darkness in lowest possible nit count for dark scenes. Getting both to happen isn’t easy. By the UHD Premium standards of the UHD Alliance, a 4K LCD TV can be considered an HDR model if it can manage at least 1100 nits of brightness while at the same time pulling off dark scenes with only 0.05 nits of light emission. For OLED 4K TVs, the blacks are perfect and much deeper than anything found in an LCD model, at only 0.0005 nits (barely detectable) in dark areas but with low levels of peak brightness, with the UHD Alliance standard requiring at least 540 nits.
Contrast of course also figures heavily in non-HDR 4K TVs with SDR display but the variations are much smaller. Your typical SDR TV might offer only 400 to 500 nits of peak brightness while managing just 0.5 nits of black level. Even many HDR TVs from 2015, before the advent of the UHD Premium and other major high dynamic range standards, usually offered no more than 600 or 700 nits of peak brightness.
- Color Enhancements
The next key component of HDR is color enhancement. This is encoded into all major HDR standards and all new 4K UHD TVs with high dynamic range must offer up processing of what is known as 10-bit color. This is considered deep color and instead of offering 256 RGB (Red, Green, Blu) values, it offers 1024 of them. This amounts to a total of 1.06 billion colors instead of the 16 million offered by older 8-bit color TVs. Thus, the gradations between shades and different tones in onscreen content present a far greater degree of realism to the viewer.
With HDR TV standards, things also get a bit more complicated than the above. For starters, 4K HDR TVs don’t actually need to be able to display all of the colors in a 10-bit signal, they just need to be capable of processing them for the sake of delivering an image based on that information. This is a sort of indirect “10-bit color capacity”.
Furthermore, in HDR TV standards, a given television has to also manage what’s called P3 color, or at least 90% of it. P3 refers to the P3 part of the total color spectrum, which is quite a bit larger than the older Rec.709 color spectrum used in previous 4K TV models.
All of the above amounts to what is also called the “Wide Color Gamut” ideal among 4K TV makers, which means wider coverage of color spectrum and much smoother gradation between all possible shades in that covered spectrum space. It’s an extended part of developing highly realistic display quality and high quality HDR.
HDR Standards Overviewed
We have already briefly mentioned several different 4K high Dynamic Range standards above, so here is more detail on those. Currently, the two dominant versions, which are actually being used in consumer market 4K TVs of one kind or another, are Ultra HD Premium, from the UHD Alliance and Dolby Vision, from Dolby Labs. Beyond them, there are also several other major HDR definitions being developed without commercial use in consumer TVs. Here are the key specs and characteristics of the two main standards today:
- Ultra HD Premium from the UHD Alliance:
These are the standards for 4K Display devices of any kind, and mainly 4K UHD TVS. For the wider UHD Alliance standards for content and content distributors, see here.
- Display resolution: minimum of 3840 x 2160 pixels
- Color bit depth: 10-bit signal
- Color Palette: (Wide Color Gamut)
- Signal Input: BT.2020 color representation
- Display Reproduction: More than 93% of the DCI P3 color spectrum
- High Dynamic Range
- SMPTE ST2084 EOTF
- Both Peak Brightness and deep black levels of either more than 1000 nits and less than 0.05 nits of black, OR more than 540 nits of peak brightness and less than 0.0005 nits of black level. (This dual contrast standard is likely a direct sop to LG’s OLED technology, which can’t match the high nit levels of LCD/LED displays but can completely outmatch them in terms of how dark their blacks go, thus re-bracketing the range which constitutes HDR and deep contrast.
TVs which match the above high dynamic range and color standards during certification testing will get an “Ultra HD Premium” label, except for Sony 4K TVs, which will get Sony’s own “4K HDR” logo for matching these same standards above.
- Dolby Vision HDR and color standards
Dolby Vision’s color and HDR standards are both a bit looser and also somewhat stricter than those of the UHD Alliance. For details on the Dolby Vision standard, you can check out the company’s white paper here.
However, these are the essentials of Dolby Vision, which are found in Netflix and Vudu 4K streaming HDR content and which are also used in TCL, Vizio and LG OLED 4K HDR TVs.
- Dolby specifies a goal of 12-bit color and a whopping 10,000 nits of brightness for the cinematic master of a piece of content. No displays can currently handle 10K bits and 12-bt color is still not quite developed, so for content that’s currently being mastered for Dolby Vision, 4K nits and 10-bit color are allowed, particularly for broadcast content.
- Variants of the 4000 nit peak brightness can also be created for HDR displays that can’t manage this but use Dolby Vision. Thus, even 4K HDR TVs that do 1000 nits of brightness or slightly more (like most of the 2016 consumer HDR TVs using the Dolby standard) can be considered certified by Dolby Vision
- Dolby Vision requires dedicated silicon inside the TV. This means it can’t be added in via firmware updates but has to actually be physically built in.
- Dolby Vision HDR does not require HDMI 2.0a and HDR TVs with Dolby like the Vizio Reference-Series models don’t have the technology.
- Dolby Vision is also now being used by streaming HDR content from Netflix and VUDU, though both companies only offer limited HDR selections for now.
- Dolby Vision is currently being applied in Vizio’s 2016 4K TVs, the LG OLED TVs for 2016 and in all TCL 4K UHD TVs with HDR for 2016.
As we’d said, other HDR standards are also being developed. These include the open source HDR10 standard and Technicolor’s own version of HDR, which is unique in that it will have the ability to turn SDR content into HDR content inside a 4K TV or other display device. However, these other standards aren’t yet found in any consumer market 4K UHD displays.
What about HDR Content?
Unfortunately, HDR televisions can’t quite yet simply take any piece of video entertainment and give it to you in high dynamic range. The content itself has to also be mastered for one type of HDR standard or another. Fortunately, this is now being done for all major sources of content from streaming to 4K Blu-ray discs in particular, which are all being put on sale with high dynamic range. The standards used vary among content providers but the majority of current 4K HDR video uses the UHD Premium specs for its mastering.
Your 4K HDR TV will of course deliver exceptional brightness and color to any content it displays, even non-ultra HD video but for the real 10-bit color coverage and wide range of peak brightness it’s capable of, the content displayed also has to be encoded with information that gives the TV instructions for greater dynamic range.
As for sources of 4K ultra HD video in HDR. There are quite a few now arriving on the market or already here. As we’d said above, all 4K ultra HD Blu-ray discs going on sale this year and for the foreseeable future are coming out with HDR encoded into them, though they can also be viewed on SDR 4K TVs without the HDR enhancements appearing. Furthermore, Amazon Prime, Vudu, Netflix and other streaming providers like Sony’s new Ultra service are all now providing high dynamic range selections. The content from Netflix and Vudu however uses the Dolby Vision HDR format and thus can only be viewed on Vizio and LG OLED 4K TVs in that format.
For the moment, your best source of high Dynamic Range content, if you have an UHD Alliance certified 4K TV or a 2015 HDR TV is to simply buy a 4K UHD Blu-ray player for the ability to watch what are already dozens of 4K movies that include HDR.
Which TVs support HDR?
4K ultra HD TVs which support high Dynamic Range are becoming the default for the UHD TV industry in 2016 and from here on out. That is to say that all major models from all major 4K TV brands released in 2016 now offer HDR. This includes all 2016 Sony 4K TVs, all 2016 Samsung 4K models and most of the 4K TVs from Vizio, LG, Panasonic, Hisense, TCL and Philips coming out or on sale this year.
For 2015 4K models, Sony’s 2015 X850C, X900C, X930C and X940C 4K Bravia TVs offered HDR, and the selection for last year also included Samsung’s SUHD JS9500, JS9000 and JS8500 4K models. However, among these televisions, only the Samsung JS9500 and the Sony X940C offer high dynamic range and color that are good enough for the certification standards of 2016.
Conclusion and Key Points to Keep in Mind
HDR is here to stay. That’s beyond a doubt at this point, especially given how much the technology improves the quality of the 4K home entertainment experience, possibly even more so than 4K UHD resolution itself. With that, yes, at some point, you’ll have to get a 4K TV with high dynamic range if you want the best in home entertainment and with that said, if you really want to get started on this now, you already can now that high dynamic range standards have settled quite a bit in 2016. Furthermore, if you’re planning on buying any kind of name brand 2016 4K TV in this year, then you’ll be getting an HDR model in any case, since virtually all new releases now come with the specs.
However, there is no need to rush out and buy a 4K HDR TV quite yet, especially not if you own a perfectly decent 2014 or 2015 4K UHD TV with an earlier version of HDR or even none at all. 4K content as a whole is still well away from really growing and most of your content viewing will be in upscaled SD and HD, both of which aren’t available in HDR anyhow. Furthermore, HDR standards are going to go a few more shifts anyhow, so you can easily wait for the dust to settle still further while you enjoy what is still a superb SDR 4K content viewing experience. HDR 4K video may be spectacular but that doesn’t mean normal 4K content is anything less than superb as it stands.