If you’ve shopped TVs recently, you’ve no doubt been seduced by the term 4K UHD or the words “Ultra High Definition.” When UHD was first introduced a few years ago, it represented a jump in resolution — basically four times the resolution of 1080p HD. That seemed like a pretty big deal, but we now know that UHD (or Ultra HD, or 4K, or whatever you call it) is now taking on an entirely new meaning. The very best TVs are not only UHD TVs but HDR TVs as well. But what is HDR TV?
HDR stands for high dynamic range. The technology behind HDR means it can provide a higher level of contrast between light and dark images on the screen to create a much more realistic image. That may not sound like much on paper, but in reality, it’s a pretty significant move. In fact, many in the industry believe HDR represents a significantly bigger leap in picture quality than UHD’s higher resolution.
Let’s be clear here: HDR is not the next “3D.” HDR is here to stay — and we couldn’t be happier about it.
HDR: The basics
Contrast is measured by the difference between the brightest whites and darkest blacks a TV can display, as measured in candelas per square meter (cd/m2), known as nits. The ideal low end is completely black, or zero nits — currently only possible on OLED displays, which can turn pixels completely off. On the high end, it’s a different story. Standard dynamic range TVs generally produce 300 to 500 nits, but some HDR TVs aim much, much higher — thousands of nits even.
Multiple formats for displaying HDR are possible, but currently there are two major players: the proprietary Dolby Vision format and the open standard HDR10. Dolby was first to the party, displaying a prototype TV capable of displaying up to 4,000 nits of brightness. For a short time, Dolby Vision was essentially synonymous with HDR, but not every manufacturer wanted to play by Dolby’s rules (or pay its fees), and many started working on their own alternatives. Companies quickly realized that this could lead to madness, and many popular manufacturers, including LG, Samsung, Sharp, Sony, and Vizio, eventually agreed on an open standard called HDR10.
In April 2016, the UHD Alliance — an industry group made up of companies like Samsung, LG, Sony, Panasonic, Dolby, and many others — announced the Ultra HD Premium certification for UHD Blu-ray players. This benchmark sets some baseline goals for HDR, such as the ability to display up to 1,000 nits of brightness and feature a minimum of 10-bit color depth. Both HDR10 and Dolby Vision meet the standards set by the certification, but how the two go about it varies greatly.
HDR10 & HDR10+
While Dolby Vision may have been first, it isn’t currently the most popular format (though it is on the rise). Instead, the most popular format is HDR10, which is supported by a wide swath of TV makers. The format isn’t as technologically advanced as Dolby Vision’s theoretical specs, but then again, neither are most Dolby Vision-enabled TVs you can go out and buy right now.
The HDR10 standard was codified by the Consumer Technology Association, the same group behind the annual Consumer Electronics Show. The spec currently uses 10-bit color depth, while Dolby Vision uses 12-bit. Both of these offer millions of colors per pixel, and the difference will be difficult to spot depending on how a given movie or TV show is mastered. Since one of the goals of HDR is to offer greater color volume, a higher color depth is desirable, at least in theory, but even 10-bit color depth is a major step up from the 8-bit color depth used in standard dynamic range TVs.
While HDR10 plays it safer than Dolby Vision, it’s also more feasible for manufacturers to implement right now.
Both of the major HDR formats in use today use metadata that rides along the video signal down an HDMI cable, and allows the source video to tell a TV how to display colors. HDR10 uses a fairly simple approach, sending metadata once at the start of a video. This is enough to essentially tell the TV: “This video is encoded using HDR and you should treat it that way.” But as we’ll show later, Dolby Vision takes a different and more thorough approach.
While HDR10 plays it more safe than Dolby Vision when it comes to technology, it’s also more feasible for TV manufacturers to implement right now, rather than in the future, so it has become the more popular of the two formats. In addition, HDR10 is an open standard — TV manufacturers can implement it free of charge. It is also recommended by the UHD Alliance, which generally prefers open standards to proprietary formats like Dolby Vision.
Then there is the matter of HDR10+, which Samsung and Amazon announced in April 2017. Unlike the original HDR10 standard, HDR10+ offers features much closer to those provided by Dolby Vision, including dynamic metadata that allows TVs using the technology to adjust brightness on a scene-by-scene or even frame-by-frame basis. Also like Dolby Vision, HDR10+ uses 12-bit color depth. Initially only available on Samsung TVs, HDR10+ is now also available on Panasonic’s 2018 4K OLED line, which was unveiled at CES 2018.
Dolby Vision’s proprietary nature means that manufacturers need to pay Dolby to use the technology in their TVs and UHD Blu-ray players. Even TVs that originally shipped with only Dolby Vision should be able to add HDR10 support via a firmware update. With HDR10+ available as an open standard, this could eventually slow down Dolby Vision’s rate of adoption, but at least for now, more and more TVs being introduced support Dolby’s technology.
HDR10 might currently be in more TVs, but that might not always be the case down the road. In terms of sheer technological might, Dolby Vision has a clear advantage, even with today’s TVs. Looking to the future, the gap between Dolby Vision and HDR10 could become even more apparent.
As mentioned above, Dolby Vision supports 12-bit color depth, as opposed to the 10-bit color depth supported by HDR10. It also features higher theoretical brightness. HDR10 currently maxes out at 1,000 nits while Dolby Vision can handle 4,000 nits, and Dolby says future upgrades could allow for up to 10,000 nits of peak brightness. Current TV panels can’t display anywhere near that, but that could change.
Color depth isn’t the only area where Dolby Vision has a theoretical advantage over HDR10. While HDR10 transmits only static metadata (when a video starts playing), Dolby Vision uses dynamic metadata, which can vary by scene or even on a per-frame basis. Again, the advantages here are mainly theoretical right now, but as content providers become more adept at mastering cinema and TV for HDR, dynamic metadata could prove a major advantage.
HDR10 might currently be better supported, both in terms of TVs and content, but Dolby is hard at work trying to change that.
The Dolby Vision spec also allows the screen displaying a video (your TV) to source data about the screen used to master the scene (in the editing lab at a studio), and it can automatically account for the differences between the two. This leads to an image that is automatically adapted to best fit your individual display, rather than relying on choices made by the mastering engineer.
HDR10 might currently be better supported, both in terms of TVs and content, but Dolby is hard at work trying to change that. Initially, Dolby Vision required dedicated hardware to work, meaning it couldn’t be added later via a firmware update. That changed in February 2017, when the company made Dolby Vision available as a software solution, meaning hardware manufacturers — including TV and possibly Ultra HD Blu-ray manufacturers — could theoretically add support later on. And while HDR10 was the first format to be supported by Ultra HD Blu-ray players, both LG and Philips announced UHD players featuring Dolby Vision at CES 2017.
More TV makers have started supporting Dolby Vision as well. Early on, only Vizio and LG sold TVs with both Dolby Vision and HDR10. More recently a number of manufacturers including Sony and Hisense have cooked up models that support both.
Dolby Vision and HDR10 are currently seen as the two biggest players in HDR, but there are other companies working on their own HDR solutions. Two other emerging formats aim to make backward compatibility with standard dynamic range a major focus.
Hybrid Log Gamma (HLG) is a format from the BBC and Japanese broadcaster NHK. As the focus of the two organizations behind the format may suggest, HLG was developed with a focus on live broadcasting, though it can also be used for prerecorded content. Unlike HDR10 and Dolby Vision, HLG doesn’t use metadata, which could be an advantage depending on how TV manufacturers implement it. For a more thorough look into HLG, we have a guide discussing both what HLG is right now, and what it could offer in the future.
Technicolor was an early player in HDR, and at CES 2016, the company announced that it and Philips had merged their efforts in HDR and were working on a new format. Like HLG, this format aims to be backward compatible with SDR displays, which the companies said in a press release “will simplify HDR deployments for distributors, who will be able to send one signal to all of their customers, regardless of which TV they have.” At CES 2018, Philips announced that its 2019 TVs would support Technicolor HDR and the ATSC 3.0 broadcast standard.
So what do we watch? (The content conundrum)
Even if your TV has the latest and greatest HDR support, color reproduction, and 4K UHD tech, much of what you watch won’t take advantage of all that awesomeness. HDR content is currently even more limited than 4K, but Hollywood (of course) is working to remedy this issue. Below are a few of the easiest and most readily available ways to get your HDR fix.
Ultra HD Blu-ray
Offering the highest-quality delivery method for a top-tier HDR experience at home, UHD Blu-ray allows for 4K UHD resolution, HDR and color expansion, and revolutionary surround sound codecs like Dolby Atmos and DTS:X. The most recent HDMI format update was largely based around clearing the way for high dynamic range devices, including new Blu-ray players and other set-top devices.
The output of Ultra HD Blu-ray releases with HDR has become the new standard, and HDR10 is currently the leader there, but 2017 has Dolby Vision working hard to catch up. Which discs do it best? Check out our picks for the best recent UHD Blu-Ray releases.
As a major provider of video, it probably comes as little surprise that Netflix was one of the first companies to announce HDR support. That made it somewhat strange when the company quietly rolled out HDR on Marco Polo without notifying anyone. Marco Polo was joined by a number of other Netflix originals, including Marvel’s Daredevil, Jessica Jones, and Luke Cage series, as well as movies like The Do-Over and The Ridiculous Six. HDR titles from Netflix are available in both HDR10 and Dolby Vision formats.
Like Netflix, Amazon announced HDR support fairly early on. A number of HDR films are available via Amazon Prime Video, along with many of its original series, including Man in the High Castle, Transparent, Mozart in the Jungle, and Red Oaks. It’s likely that most if not all of Amazon’s future original programming will also be available in HDR.
Amazon initially only supported HDR10, but in June of 2016 the company added support for Dolby Vision. At the time, the company said that more titles were available in HDR10, with a subset available with Dolby Vision, but it added over 100 hours of HDR content in both formats by the end of 2016.
In December 2017, Amazon added more than 100 titles in the HDR10+ format, including series like The Man in the High Castle, The Tick, and The Grand Tour. The company plans to add more titles in HDR10+ moving forward.
One of the earliest providers of 4K programming, Vudu was also quick to offer HDR support. The service offers one of the largest libraries of 4K movies and TV shows available for rent or purchase, many with HDR as well as Dolby Atmos surround sound.
For some time, Vudu’s HDR offerings were only available in Dolby Vision. In November 2017, the company announced complete support for HDR10, making its library of HDR titles available on a far greater range of devices.
What about gaming?
While most guides focus on passive viewing experiences for HDR, game consoles are an important part of the discussion. With the PlayStation 4 Pro, Xbox One S, and Xbox One X, Sony and Microsoft have thrown their hats into the HDR ring, but it can be much more complicated to access all that sparkly goodness than you might expect.
Xbox One S & Xbox One X
We’re kicking off with Microsoft’s update to the Xbox One because it’s a much simpler story overall. While the first-generation Xbox One didn’t feature support for either 4K or HDR, the revamped version features both. In addition to 4K support (complete with HDMI 2.0a and HDCP 2.2) HDR10 is supported for both games and general entertainment purposes, though Dolby Vision is not.
Xbox streaming in HDR is currently limited to Netflix, but Microsoft has taken things a step further by including an Ultra HD Blu-ray drive built-in, meaning you get twice the bang for the buck — especially considering the Xbox One S is priced competitively with many UHD Blu-ray players currently on the market.
The system does not support native 4K Ultra HD content for gaming. Instead, video is upscaled to 4K. That feature is present in the Xbox One X, however. HDR is supported for a number of games, including Battlefield 1, Gears of War 4, and Forza Horizon 3.
PlayStation 4 Pro
Unlike Microsoft’s first effort, Sony did add HDR to the original PS4, but without 4K Ultra HD support. That means it won’t be very helpful as a streaming device for HDR, especially since apps like Netflix and Amazon currently only support HDR alongside 4K. The HDR support on board here will only be useful for a select number of games which include HDR, though more are expected to roll out soon.
Like the Xbox One S, the PlayStation 4 Pro features HDMI 2.0a and HDCP 2.2, and supports HDR10 but not Dolby Vision. This allows the PS4 Pro to supports both 4K and HDR, but currently there isn’t any way to watch anything in HDR, as the Netflix apps for Amazon and Netflix don’t support 4K or HDR. For now, it’s only useful for gaming.
Unlike the Xbox One S — and this is key for home theater enthusiasts — Sony didn’t include a UHD Blu-ray drive in the PS4 Pro. That’s somewhat of a surprise considering how much the built-in DVD drive drove sales of the PlayStation 2, while the PlayStation 3 helped Sony’s own Blu-ray format win the high definition hardware war over HD-DVD.
While native 4K gaming isn’t supported on the Xbox One S, it is possible on the PS4 Pro, though it’s a complicated situation, as some games are native while others are upscaled. HDR gaming is supported for a variety of titles, including Uncharted 4: A Thief’s End, The Last of Us: Remastered, Thumper, and many more.
Then there’s the VR complication. Sony has also focused heavily on virtual reality with its PSVR hardware, but this presents a problem for those who would like to game in HDR, as the two are currently mutually exclusive. “If you’re playing a normal, non-VR game on your PS4 Pro, PS VR’s Processor Unit will output a 4K signal to a 4K TV,” Sony blog post reads. “The Processor Unit does not support HDR pass-through,” the post continues, meaning you’ll have to go directly into the TV from the PS4 Pro to view HDR content.
That is less than ideal, but both consoles are dealing with their fair share of issues related to 4K and HDR. As time goes on, bugs will likely be worked out, though it remains to be seen if anything to fix the issue with PSVR is even possible.
So there you have it. High Dynamic Range is a lot more complex than just three little words. But it’s also a very exciting technology that will pull us even deeper into the spectacular movies and TV series we love to watch, creating more brilliantly realistic images than ever. If you’re wondering if the next TV you buy should be HDR compatible, our answer would be: Yes. HDR is the most meaningful upgrade to the home video viewing experience that we’ve seen since the introduction of the Plasma TV and the jump to high definition, and it’s definitely at the core of television’s future.
Update: Added more information on HDR10+, HLG, and Technicolor HDR.