What Is HDR TV and Why Does It Matter?

Every year, TV makers engage in a game of one-upmanship and try to create the perfect TV. The quest for the perfect picture is now focused on HDR, which promises to deliver more realistic colors and shades to create a true cinematic experience at home. HDR is still an unsettled technology, so to sort out what it means to shoppers now, here are all the answers you need to know before you buy.

What does HDR stand for?

HDR stands for high dynamic range, a reference to its ability to deliver more colors, more contrast levels, and increased brightness over standard HD and even standard 4K Ultra HD sets. HDR is essentially an upgrade of the 4K or Ultra HD format (it is not applicable to 1080p HD sets).

Though many LCD TVs can produce a wide range or gamut of color, they have been limited to an outdated video specification (known as Rec. 709). HDR promises more realistic colors and much higher brightness levels (1,000 nits or more) than new LCD and OLED sets are capable of producing.

Will I notice a difference when watching HDR content?

If you're watching an HDR movie or show on an HDR TV, yes, you will definitely see an improvement. It can make invisible faces in a dark scene visible and eliminate the kind of annoying color banding that occurs between colors as an image makes the transition, say, between various shades of orange and red in a sunset. 

HDR illustration. Composite: Shutterstock, Kenneth Butler/Tom's GuideHDR illustration. Composite: Shutterstock, Kenneth Butler/Tom's GuideOn the other hand, many of the first HDR TVs will only meet the minimum or near-minimum requirements of the specifications, so the differences may not be so startling on those sets. Furthermore, as DisplayMate president Raymond Soneira points out, not all content is worth the HDR treatment. For example, the jungle scenes of HDR 4K video are impressive in demonstrations, but not all video material contains the same level of color saturation as a bright green frog sitting on a red leaf.

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Another important factor that affects our perception of the realism of a video image is the frame rate of the video. Ultra HD Premium sets will support rates of 24 frames per second (like film) up to 120 frames per second. At 120 fps, video looks much more solid, and there's less blurring of fast objects such as cars in a chase scene or of someone trying to steal second base. So how good the picture looks will depend on the frame rate of the HDR program.

To watch HDR programs, what do I need?

Before you ever watch a movie on your TV, the film has been compressed from its original color range to fit into the old video format, essentially eliminating colors, contrast and image depth. In theory, HDR restores some of that lost color and contrast, but it requires remastering the original show, in essence producing a new version of the movie or program.

HDR can make invisible faces in a dark scene visible.

So to get the full benefit of HDR, not only must you have a compatible TV set, you must also have access to HDR content and programming.

What HDR content is available?

Initially, only a handful of 4K HDR programs will be offered on streaming services from Netflix, Vudu and Amazon. YouTube also has a few compatible programs, but not all will offer Dolby Vision HDR shows.

The HDR pickings are extremely thin. Netflix has talked it up a lot, but so far hasn’t released any series or movies in the format. Amazon offers two shows to Prime members in HDR: Mozart in the Jungle and Red Oaks.

Credit: AmazonCredit: AmazonAlso new this year will be 4K Ultra HD Blu-ray players that will support HDR discs. But again, not all will support Dolby Vision. And the discs are expensive; the HDR 4K version of The Martian is $30. About 20 movie titles supporting HDR and Dolby Vision have been announced (including The Lego Movie, The Martian, Mad Max: Fury Road, The Man from U.N.C.L.E., American Sniper, Man of Steel and Edge of Tomorrow), however, none are yet available and no official release dates have been published to date. 

How do I know if a TV is HDR-compatible?

While there are efforts to standardize on a single HDR specification, at the moment there is no single, universally agreed-upon HDR spec.

“There is definitely a bit of a format war going on at present,” said Paul Gray, a principal analyst and researcher at IHS.

Credit: UHD AllianceCredit: UHD AllianceYou'll see two HDR formats touted by TV manufacturers in stores and online that indicate a TV is HDR-ready. One is Ultra HD Premium. Established by the UHD Alliance, the Premium standard is backed by dozens of companies, including movie studios and TV makers. It applies mainly to TVs and forthcoming 4K Blu-ray players, and sets a minimum specification for sets, which allows them to stick the iridescent Ultra HD Premium logo on the box. (The format, which is also sometimes referred to as HDR 10, does not specify that a particular encoding system must be used for movies, so that battle in Hollywood may continue for some time.)

Credit: DolbyCredit: DolbyThe other logo you're likely to see on HDR 4K Ultra HD sets is Dolby Vision. Created by the surround-sound folks, Dolby Vision lays out a set of specifications that stretch from movie production to broadcast TV to the televisions that can play Dolby Vision HDR material. Dolby Vision sets a higher technical standard in some respects for HDR than Ultra HD Premium, although not all Dolby Vision-labeled sets will be able to meet the maximum specifications.

Today’s Blu-ray video uses 8-bit color for roughly 16.7 million colors. Moving up to 10 bits yields well over a billion colors.

HDR is still in its infancy, so there is no conclusive winner as yet. The good news is that whatever HDR set you buy today, it will be backward-compatible. In other words, all HDR TVs will upscale or convert regular HD content to display on their screens, although the picture improvement won't be as profound as what you'll see with true HDR content.

What is the difference between Ultra HD Premium and Dolby Vision?

Some TVs are Ultra HD Premium-compatible (like Samsung), others are Dolby Vision-compatible (like Vizio) and some are compatible with both (like LG). So what's the difference?

Ultra HD Premium establishes several general capabilities that TVs have to possess to be HDR-compatible. There are a variety of components, including audio requirements, the already-established 3840 by 2160-pixel Ultra HD resolution and the elimination of an interlaced picture (the “i” in 1080i). But the primary changes involve color and brightness/contrast. Ultra HD Premium sets the color depth to a 10-bit signal (versus the current 8-bit depth) and minimum peak brightness at 1,000 nits (with an exception for sets that can produce true black, and therefore more contrast, like OLED models).

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By way of comparison, HD and Blu-ray video use 8-bit color for a possible total color palate of roughly 16.7 million shades. Moving up to 10 bits yields well over a billion possible colors.

An Ultra HD Premium TV also has to be able to reproduce more than 90 percent of a color spectrum specification that is called DCI P3. Also known as color gamut, it's the total possible range of colors a video or TV can produce. DCI P3 is from the Digital Cinema Initiative, whose spec is used for the movies you see in theaters. That makes it an obvious choice — and a big improvement — over the limited Rec. 709 format. (There is another even wider proposed color scheme, Rec. 2020, but current TVs are not capable of displaying all of its colors, and new digital movies would have to be shot in the format.)

Dolby Vision contains more HDR-format details, but for consumer televisions, it also emphasizes color reproduction and brightness. Dolby requires a 12-bit color depth, with a possible 68 billion shades. As DisplayMate's Soneira explains it, "8 bit is awful, 10 bit is good, and 12 bit is what you need."

Dolby Vision also sets the brightness bar higher, requiring levels of 4,000 nits or more. The catch is that while TVs with the Dolby Vision logo will be certified by Dolby, not all Dolby-certified sets will meet all of the specifications we're hearing about. In other words, many sets won't meet that 4,000-nits mark, including OLED TVs. However, LG’s sets will be officially Dolby Vision-compatible and certified.

So which is better, Ultra HD Premium or Dolby Vision?

On paper, Dolby Vision sets should deliver a better HDR picture than Ultra HD Premium TVs. And a set that's Dolby Vision-compatible should also be able to handle the lesser requirements of Ultra HD Premium.

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However, that may not always be the case. Manufacturers that don't choose to license Dolby Vision technology may nevertheless make TVs that exceed the HDR capabilities of Dolby-labeled TVs. That could mean that there may be sets with an Ultra HD Premium sticker that look superior to other models with a Dolby Vision label. (Never mind considering the differences between, say, OLED and LCD sets.)

Can my TV be upgraded to HDR?

A few TVs can in fact be upgraded to handle HDR programs. Most of the sets that can do so are recent top-of-the-line models, and they require a software download (usually done easily over the TV's existing Wi-Fi connection). 

Samsung's 2015 UN65JS9500 (about $4,200) is one example of a set that can be upgraded via a software download. It already has the technical ability to meet the Ultra HD Premium specifications. Samsung says other 2015 sets may also be upgradable.

The 2015 Samsung JU9500 can be upgraded to HRD. Credit: SamsungThe 2015 Samsung JU9500 can be upgraded to HRD. Credit: SamsungHowever, some confusion is bound to ensue among shoppers as TV makers will also be claiming that some 4K Ultra HD sets are "compatible" with HDR content, but won't be able to meet the Ultra HD Premium specification. In other words, they will be able to play HDR video, but not reproduce all the available colors or brightness levels. 

What comes after HDR? Should I wait for 8K?

As TV makers and movie studios get accustomed to the new format, better TVs and more finely crafted HDR-mastered movies are bound to appear. However, today's TVs are better than yesterday's TVs, so there's no reason to avoid buying a set.

For several years, there has been discussion about and experimentation with so-called 8K televisions delivering double the number of pixels of 4K Ultra HD. However, it's never gone beyond experimentation.

“The big problem is not making the displays,” according to IHS's Grey. He says the problem is that the data rate necessary to transmit 8K is “gigantic.” Not to mention how big an 8K set would have to be in order for viewers to appreciate all those extra pixels.

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