Buyer Beware! How To Tell If Your New 4K/UHD TV has HDR

Before you go out and buy a new 4K/UHD TV, beware! Even though a TV may say 4K/UHD, it could be missing a critical feature, preventing you from getting the most from UltraHD content: High Dynamic Range or HDR. Believe it or not, not all 4K/UHD TVs support HDR.  Therefore, let's look at why HDR is important, how you can tell if a 4K/UHD TV has HDR, and why you don't want to buy a 4K/UHD TV without it.

Isn't better resolution an important TV feature?

The resolution jump from 480p (standard definition or SD) to 1080p (high definition or HD) TV was immediately noticeable to the naked eye. However, the jump from 1080p (HD) to 2160p (4K) resolution on average-sized displays (65-inch and under), doesn't play a huge role.  Believe it or not, depending on seating distance you may not even be able to tell the difference between a 1080p (HD) and 2160p (4K/UHD) picture based on resolution alone! We should note that the same has also been true of 720p vs 1080p on smaller HD sets.

The importance of 4K/UHD isn't just about increasing total pixels (1920x1080 vs 3840x2160). Rather, the real benefit lies in the broader technologies that make up the UltraHD part of the 4K/UHD equation.

UltraHD refers to a complementary set of standards and features differentiating today's TVs from their predecessors.  Here at Audioholics, we believe that the two most important standards are BT-2020 (wide color gamut) and SMPTE-2084 (HDR). While we'll give a nod to other technologies that make up other UHD specs, like high frame rate, there's no question that wide color gamut and HDR are probably the most critical.

Increased Color with a Wide Color Gamut

Let's first talk about wide color gamut. The color spectrum below shows a representation of colors the average human visual system can see. Good old HD televisions were able to display colors that conformed to the REC709 color gamut, which is roughly 30% of the human visual system. HD television programing and Blu-rays were all mastered to the REC709 specification. That's why you've probably noticed some colors on your Blu-rays or HDTV programming—especially greens and reds—aren’t as vibrant as real life.

Today's 4K/UltraHD TVs and UltraHD Blu-rays, by contrast, are able to display content that has goes beyond REC709. The BT-2020 standard encompasses 75% of the colors humans can see. A TV with wide color support is therefore far closer to capturing all the colors the average person experiences each day.

While BT-2020 offers a lot of color opportunity, most content today is using only a fraction of it. For example, that third triangle, labeled P3, is the color space that most commercial movies in cinema are mastered to.

The benefit of watching UltraHD content is that you'll be able to experience a far wider spectrum of colors that look more true-to-life. Finally, fire trucks will look fire truck red and Coke cans will resemble the real thing.  The benefits of improved resolution and wide color gamut are easy to understand. Now, let's look at the secret sauce that ties everything together: HDR.

High Dynamic Range: 4K/UHD TV's Secret Sauce

In a nutshell, high dynamic range drastically increases the contrast between the brightest whites and darkest blacks without any loss in detail. But HDR is, in fact, more than just contrast. HDR actually enhances the performance of other technologies in 4K/UHD displays. Let's see how and why.

To get under the hood, I spoke with Carlos Angulo, Director of Product Marketing for Vizio about the importance of HDR in today's displays. Vizio is one of the few companies that offers HDR throughout their entire 2018 4K/UHD models—from their entry level D-Series to their flagship P-Series Quantum.

I asked Mr. Angulo why HDR is such an important part of today's 4K/UHD experience.

"Ultra High Definition has an impressive 8 million pixels, with 4x the detail of 1080p for sharper detail in every image, but High Dynamic Range (HDR) expands the image’s range of contrast and color volume, delivering a difference in picture quality you can easily see. High Dynamic Range dramatically extends the contrast range between the brightest white highlight and darkest black areas on the screen for astonishing brightness and striking contrast without loss of detail. As a result, the glistening chrome trim of a car, the beam of a street lamp against a dark street, or the shimmer of sunlight off the water have the brilliance and detail they deserve. To reproduce the bright highlights of this extended range, Vizio TVs use UltraBright technology, with up to 2000 nits of light output to increase the luminance of important highlights.”

- Carlos Angulo, Director of Product Marketing for Vizio

Given that explanation, one might think of HDR as just brighter whites and darker blacks. But that's not all. HDR preserves a color's saturation as it gets brighter. This is why HDR and wide color together are a big deal. Look at the 3D color volume diagram below representing a color's brights and darks and now you can really understand why HDR makes such a huge difference.

HDR makes an even bigger difference with color volume.

Here you can see the difference between BT-2020 vs. REC709 rectangles as you increase a display's brightness, thanks to HDR.

Previously, making things brighter would wash out colors until they became white. That's not what happens with HDR. A color retains its saturation even when it gets brighter. I asked Mr. Angulo to explain the relationship between luminance and increased color and why the two are so important to a full 4K/UHD experience.

"High Dynamic Range is a combination of increased luminance or dynamic range, and increased color, or color gamut, and the relationship between them. With the increased luminance, for example, typical colors like a blue sky can be even more vibrant and lifelike than they could be in a standard high definition image, even if the color is the same. The user will experience a more vibrant and lifelike image thanks to the fact that the color palette can be so much brighter."

Vizio says their P-Series Quantum 4K/UHD TV is capable of peak brightness of 2,000 nits and supports Dolby Vision HDR.

How can you tell you're purchasing a 4K/UHD TV with HDR?

The one-two combo of wide color and HDR make investing in a 4K/UHD TV worth it.  So now here's the big question: How can you be sure you're purchasing a TV with HDR? As we mentioned, Vizio is one of the few companies that has implemented HDR in their entire 4K/UHD product lineup. But that’s the exception to the rule.

If the label doesn't clearly say HDR, the TV doesn't support it!

Note that the Sony label shown above (top) does not indicate HDR while the Vizio label below it indicates HDR and further specifies Dolby Vision support in the features.

The most important thing you can do as a consumer is read the labels carefully. Make sure the TV specifically says it supports HDR. Furthermore, look for the actual HDR formats that the TV supports and if the TV has built-in apps, which apps (Netflix, Amazon, Hulu, etc.) support HDR. Let me emphasize this last point: You can purchase a 4K/UHD TV with HDR, but its internal apps might not support HDR!

What HDR specs should I look for in a TV?

Pick the right HDR formats

Now that we've seen how important HDR is to getting the most out of 4K/UHD content, the question is what specs you want to look for. There are two primary elements: HDR formats and brightness, expressed in nits. All 4K/UHD displays measure their brightness in nits. For comparison, one nit describes a brightness of 1 candela per square meter. For those of you used to Foot Lamberts (ftL), 3.4 nits is equivalent to approximately 1ftL. So a TV that’s putting out 1,000 nits is delivering about 291.8ftL.

At Audioholics, we recommend that you purchase a TV that supports both HDR10 and HLG (hybrid log gamma) HDR formats.  HDR10 is the de-facto HDR standard that comes with all HDR-enabled TVs. HLG is the forthcoming standard for 4K/UHD broadcast TV programming. You can read more about the future of 4K/UHD broadcast TV, better known as ATSC 3.0. Therefore, to future-proof your TV as much as possible you want to make sure you have these two formats at a bare minimum.

There are two other HDR formats that are important to note, and we suggest that your 4K/UHD supports at least one of these two. The first and most widespread is Dolby Vision. Dolby Vision support will take your HDR and 4K/UHD experience even further. Dolby Vision uses dynamic metadata, which can adjust HDR on a scene-by-scene or even frame-by-frame basis. Content mastered with Dolby Vision can therefore adjust peak brightness and black level on the fly so you're getting the best image possible.

Dolby Vision HDR uses dynamic meta data and can adjust HDR on a scene-by-scene or frame by frame basis.

HDR10, by contrast, uses static metadata and sets peak brightness and black level for the entire movie or program. Because HDR10 can't adjust peak brightness and black level on the fly, images sometimes come across too dark. In order to take advantage of Dolby Vision, your display, source (i.e. 4K/UltraHD player), and content all need to support Dolby Vision. If they don't, then you'll only be getting HDR10. Not all displays with HDR, UltraHD Blu-ray players, or streaming boxes support Dolby Vision.

The other emerging HDR standard worth noting is HDR10+. HDR10+ is spearheaded by Samsung and you'll see HDR10+ on all new 2018 QLED Samsung TVs. Like Dolby Vision, HDR10+ attempts to address the shortcomings of HDR10 by introducing dynamic metadata. However, HDR10+ falls short of Dolby Vision's support for 12-bit color and up to 10,000 nits of brightness.

Yes, we're entering a bit of a format war between Dolby Vision and HDR10+. Right now there are far more movies available in Dolby Vision (See Dolby Vision movie list). However, Amazon, Warner Bros. and 20th Century Fox have joined the HDR10+ bandwagon. And in case you're wondering, your entire signal chain must support HDR10+ to take advantage of it.

Check the TV's peak brightness and panel bit depth support

We strongly suggest purchasing a TV with the best peak brightness (expressed in nits) and black level you can afford. You'll need to measure LED-based displays and OLED-based displays differently because LED-based displays can get far brighter than OLED.  OLED displays give you truer black levels that LED-based displays can't quite match.

Here's our rule out thumb: As the technology stands today, look for entry level HDR-enabled LED models to deliver 400 nits; midrange HDR-enabled models to be capable of about 600 nits; high-end models to deliver around 1,000 nits; and flagship models to push out out 1,500 nits or more.  Of course, you'll likely see entry level and midrange sets  getting a boost in their nits spec each year.

However, to take optimal advantage of HDR with LED technology, consider a TV that puts out at least 1,000 nits. Vizio claims their stunning P-Series Quantum (which I had a chance to sample first-hand at the company's unveiling) will go as high as 2,000 nits. Remember that OLED displays need to be considered differently because they won't reach close to 1,000 nits; they make up for it in the other direction by delivering true black levels.

OLED and LED displays need to be judged differently.

OLED displays like LG's E8PUA pictured above, won't pump out anywhere close to 1,000 nits, but make up for things with their true black levels.

Does your TV support 10-Bit color?

The final item you want to check is if your 4K/UHD TV's display panel will support 10-bit color from input to output or if it down-samples a 10-bit input to 8-bit. A panel that supports 10-bit from input to output will be far less prone to banding.  Banding is a rough, stepped transition from one color or luminance to another. Banding makes the progression of color shades look more like the distinct bands of a rainbow or concentric rings instead of a smooth gradient. 

It's more difficult to find out if your TV panel has true 10-bit capability. You typically won't see a display's bit-depth listed in the specs. Nevertheless, be sure to ask, read reviews, and check online forums so you're making an informed decision. Purchasing an UltraHD Premium-certified TV helps but might not guarantee true 10-bit performance. You can read more about UltraHD Premium Certification here.

Conclusion

In summary, there's really no better time to buy a UHD TV. When you do, make sure your TV supports HDR. The most important thing you can do as a consumer is read the specs before you buy. HDR10 and HLG support are a must with either Dolby Vision or HDR10+ added for improved performance. Be sure to buy a TV with the best brightness and black levels you can afford.

Let us know what UHD TV you currently own or plan on purchasing in the near future in the discussion thread below.