If you’re shopping for a new 4K ultra-high-definition TV, it almost certainly supports high-dynamic-range (HDR) video. But what’s the difference between the competing HDR formats? Should you factor this into your purchase?
What Is HDR?
HDR stands for high dynamic range. It refers purely to the visual presentation of movies, TV shows, video games, or images. In essence, HDR provides a better, brighter image with more detail than a standard definition video or image.
While standard definition content (or SDR) is limited to eight bits per channel of color information, HDR uses 10-bit color as a baseline (some standards support up to 12 bits). A higher color bit depth means more shades of the same color, which significantly reduces a phenomenon called “banding.”
Video presented in 8-bit color is limited to 256 shades per channel, while HDR video increases that to 1,024. This results in smoother transitions between different shades of the same color for a more lifelike image. This applies to grays, too, improving near-black performance for better detail in shadows and dimly lit scenes.
In addition to the wider color gamut, high-dynamic-range video also affects overall image brightness. SDR video is mastered at 100 nits of peak brightness, a level all standard-definition displays are designed to meet. HDR video is mastered at a much higher peak brightness of 1,000 nits or more, depending on the format.
This means HDR content can get much brighter, for a more realistic image. This doesn’t mean the whole scene is always much brighter than SDR video, but rather, individual elements. This could be a candle in the dark, the sun, or the flash of an explosion.
To truly understand what makes HDR so much better than SDR, you have to experience it.
HDR10: The “Standard” Implementation
HDR10 is the baseline standard on every HDR-compliant TV. If you buy a 4K Ultra-HD Blu-ray with an “HDR” sticker on it, it will be presented in HDR10. Some of those Blu-rays support other HDR standards, too. However, HDR10 is the “compatibility mode” all TVs can fall back on.
Content produced for HDR10 is mastered at up to 1,000 nits of peak brightness. It uses static metadata to define average frame light levels and maximum brightness, which help your TV understand how to present the whole production. Although HDR10 is the “standard” HDR format, it will still look significantly better than SDR content.
Since HDR10 is an open format, it also has a wide range of support from both TV and monitor manufacturers and content producers. Ten-bit cameras, like the Panasonic GH-5s, and displays that can reach 1,000 nits of peak brightness, have made producing HDR10 content far more accessible than it once was.
As a result, you’ll find HDR10 content everywhere, including lots of free content on YouTube. Although there are virtually no standards for HDR gaming, consoles and Windows use HDR10 to deliver games in high dynamic range, as well.
HDR10+: Improved HDR with Dynamic Metadata
HDR10+ is another open standard, but it’s produced by Samsung and Amazon Video. It improves on HDR10 by using dynamic metadata that can adjust luminance on a per-scene or frame-by-frame basis. Content produced in HDR10+ is currently mastered at up to 4,000 nits of peak brightness. This means HDR10+ content can get much brighter than HDR10.
The HDR10+ standard is also equipped to support videos of up to 16-bit color depth, 8K resolution, and a peak brightness of 10,000 nits. However, at this writing, no content has been produced that even approaches these specifications.
The biggest problem with HDR10+ is its lack of availability. Presently, Samsung is the only big-name manufacturer to go all-in on it, although, there’s been limited support from Panasonic, Vizio, and Oppo.
Content is also sparse—at this writing, only Amazon Video offers streaming content in HDR10+.
Dolby Vision: A Proprietary Format with Dynamic Metadata
Dolby Vision is a direct competitor of HDR10+, and it shares many similarities from a technical standpoint. Current Dolby Vision content is mastered at a brightness of up to 4,000 nits, but it will support up to 10,000, as well as 8K resolution in 12-bit color, in the future. It also uses dynamic metadata for scene-by-scene adjustments to improve overall picture quality.
Because Dolby Vision is a proprietary format, TV manufacturers have to pay to implement it. It’s mostly found on high-end TVs, but it’s been widely adopted by LG, Sony, TCL, Hisense, Panasonic, and Philips. Samsung is the only notable manufacturer to have shunned Dolby Vision entirely in favor of HDR10+.
If you really search, there are TVs out there that support all formats. However, HDR10+ is noticeably harder to find than Dolby Vision. There’s also simply a lot more content available in Dolby Vision. Many Netflix and Disney+ shows are produced in Dolby Vision, with support for some shows on services like Amazon Prime Video and VUDU.
As Dolby Vision is closely tied to content produced for Dolby Cinemas, this has likely given the format the necessary boost for widespread support among content producers.
There’s also support for Dolby Vision in the Xbox Series X and Series S, which promise to deliver the first Dolby Vision gaming experiences in 2021. We’ll have to wait to see how that pans out, but it’s something to keep in mind if you’ll be buying a next-gen Xbox any time soon.
Hybrid Log-Gamma: The Broadcast Standard
Broadcast standards evolve differently than production standards, but that doesn’t mean sticking with SDR forever. Hybrid Log-Gamma (HLG) is an open-broadcast format developed by the BBC in the U.K. and NHK public in Japan. It’s a backward-compatible format that implements HDR video over broadcast. HLG specifically targets a peak brightness of 1,000 nits, like HDR10.
Because broadcasts have to account for such a wide array of devices with differing abilities, ensuring that modern HDR broadcasts display correctly on older SDR displays is essential. HLG accomplishes this by delivering a signal that allows modern HDR displays to achieve greater dynamic range without closing the door on older technology.
Although this format was created for broadcasts, it’s also supported by streaming services, including YouTube and BBC iPlayer. Broadcasters already using HLG include Eutelsat, DirecTV, and Sky U.K.
Advanced HDR by Technicolor: Dead on Arrival
One HDR format that failed to capture any audience was Advanced HDR by Technicolor. Pioneered by LG and Technicolor, the format first appeared around 2016. It made its way into LG televisions until 2019, when the company abruptly removed support for the format from its 2020 lineup. This effectively killed off the technology.
The primary issue with Technicolor’s effort was the lack of content. As of September 2020, we couldn’t find a single film for sale mastered in Advanced HDR or any streaming service that supports it. This makes Advanced HDR by Technicolor the HD-DVD of HDR.
Which Format Should You Invest In?
If you’re buying an HDR TV in 2020 (or beyond), it will support HDR10, which is a huge leap in dynamic range and brightness over standard-definition content. If you’ve yet to experience HDR10 content, you’re in for a treat! To benefit from it, you’ll need a TV that gets somewhere close to 1,000 nits of brightness and content mastered to take advantage of it.
Beyond HDR10, Dolby Vision has the widest support among both content producers and television manufacturers. More Blu-rays and streaming services are available in Dolby Vision. The format is also fairly future-proof because we won’t see the best it has to offer until display technology matures further. However, both Roku and Google will release streaming boxes that support Dolby Vision this year.
You also have plenty of TVs to choose from that support Dolby Vision, while HDR10+ support is limited mostly to Samsung. Vizio and Hisense produce TVs that support both, but not every model. Also, very few films are mastered in HDR10+ and only Amazon produces streaming content for it.
Because HLG is a broadcast standard, most modern TVs will support it moving forward. Your display doesn’t have to support HLG for you to receive broadcasts, though. If you don’t watch much network TV or cable, you can put HLG low on your list of priorities.
In most cases, the TV you choose will dictate the standards you can enjoy. Given that, you’ll also want to understand the difference between display technologies so you can make an informed choice.