If you̵7;re shopping for a new 4K ultra-high-definition TV, it almost certainly supports high-dynamic-range (HDR) video. But what is the difference between competing HDR formats? Should you consider this in your purchase?
What is HDR?
HDR stands for high dynamic range. It refers only to the visual presentation of movies, TV shows, video games or pictures. Basically, HDR provides a better, brighter image with more detail than a standard definition video or image.
While the standard definition content (or SDR) is limited to eight bits per channel with color information, HDR uses 10-bit color as the 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 it to 1,024. This results in smoother transitions between different shades of the same color for a more realistic image. This also applies to grayscale, which improves almost black performance for better details in shadows and dimly lit scenes.
In addition to the wider color gamut, high dynamic range video also affects the brightness of the overall image. SDR video is mastered at 100 nits maximum brightness, a level that all standard displays are designed to meet. HDR video is controlled with a much higher peak brightness of 1000 nits or more, depending on the format.
This means that HDR content can be much brighter for a more realistic image. This does not mean that the whole scene is always much brighter than SDR video, but rather individual elements. This can be a light in the dark, the sun or an explosion.
To truly understand what makes HDR so much better than SDR, you need to experience it.
HDR10: “Standard” implementation
HDR10 is the base line of all HDR-compatible TVs. If you buy a 4K Ultra-HD Blu-ray with an “HDR” sticker on it, it will be presented in HDR10. Some of these Blu-rays also support other HDR standards. But HDR10 is the “compatibility mode” that all TVs can fall back on.
Content produced for HDR10 is controlled at up to 1,000 nits maximum brightness. It uses static metadata to define average frame light levels and maximum brightness, which helps your TV understand how the entire output should be presented. Although HDR10 is the “regular” HDR format, it will still look significantly better than SDR content.
As 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, such as the Panasonic GH-5s, and screens that can reach 1000 nits of maximum brightness, have made HDR10 content much 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 games, consoles and Windows use HDR10 to deliver high dynamic range games as well.
HDR10 +: Enhanced HDR with dynamic metadata
HDR10 + is another open standard, but it is produced by Samsung and Amazon Video. It is enhanced on HDR10 by using dynamic metadata that can adjust the brightness per scene or frame by frame. Content produced in HDR10 + is currently controlled at up to 4000 nits maximum brightness. This means that HDR10 + content can be much brighter than HDR10.
The HDR10 + standard is also equipped to support videos with up to 16-bit color depth, 8K resolution and a maximum brightness of 10,000 nits. However, at the time of writing, no content has been produced that even approaches these specifications.
The biggest problem with the HDR10 + is its lack of availability. Currently, Samsung is the only major name maker to go all-in on it, but there has been limited support from Panasonic, Vizio and Oppo.
The content is also sparse – at the time of writing, only Amazon Video offers streaming content in HDR10 +.
Dolby Vision: A proprietary format with dynamic metadata
Dolby Vision is a direct competitor to the HDR10 +, and it shares many similarities from a technical point of view. Current Dolby Vision content is controlled with a brightness of up to 4000 nit, 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 the overall image quality.
Because Dolby Vision is a proprietary format, TV manufacturers have to pay to implement it. It is mostly available on high-end TVs, but it has been widely adopted by LG, Sony, TCL, Hisense, Panasonic and Philips. Samsung is the only notable manufacturer to have avoided Dolby Vision entirely in favor of the HDR10 +.
If you are really searching, there are TVs that support all formats. But HDR10 + is noticeably harder to find than Dolby Vision. There is also simply a lot more content available in Dolby Vision. Many Netflix and Disney + series are produced in Dolby Vision, with support for certain programs on services such as Amazon Prime Video and VUDU.
Because Dolby Vision is closely tied to content produced for Dolby Cinemas, this has likely given the format the necessary boost for broad support among content producers.
There is also support for Dolby Vision in Xbox Series X and Series S, which promises to deliver the first Dolby Vision gaming experiences in 2021. We’ll have to wait and see how it goes, but there’s something to keep in mind Buy a next generation Xbox anytime.
Hybrid Log-Gamma: Broadcast Standard
Shipping standards are developing differently from production standards, but that does not mean sticking to SDR forever. Hybrid Log-Gamma (HLG) is an open broadcast format developed by the BBC in the UK and the NHK public in Japan. It is a backward compatible format that implements HDR video via transmission. HLG is specifically aimed at a peak brightness of 1000 nits, such as HDR10.
Because broadcasts must account for such a wide range of devices with different capabilities, it is important to ensure that modern HDR broadcasts are displayed correctly on older SDR monitors. HLG achieves this by delivering a signal that allows modern HDR monitors to achieve a greater dynamic range without closing the door to older technology.
Although this format was created for broadcast, it is also supported by streaming services, including YouTube and BBC iPlayer. Broadcasters who already use HLG include Eutelsat, DirecTV and Sky UK
Advanced HDR by Technicolor: Dead on arrival
One HDR format that failed to capture an audience was Advanced HDR by Technicolor. Pioneers of LG and Technicolor first appeared in the format around 2016. It entered LG TV until 2019, when the company suddenly removed support for the format from its 2020 series. This effectively killed off the technology.
The main problem with Technicolor’s effort was the lack of content. As of September 2020, we could not find a single movie for sale that was mastered in Advanced HDR or any streaming service that supports it. This makes Advanced HDR by Technicolor an HD-DVD for HDR.
Which format should you invest in?
If you buy an HDR TV 2020 (or later) it supports HDR10, which is a big step in dynamic range and brightness compared to standard definition content. If you have not yet experienced HDR10 content, you can enjoy it! To take advantage of it, you need a TV that comes somewhere close to 1000 brightness and content that is mastered to take advantage of it.
In addition to HDR10, Dolby Vision has the largest support among both content producers and TV producers. More Blu-rays and streaming services are available in Dolby Vision. The format is also quite future-proof as we do not see the best it has to offer until the screen technology matures further. But both Roku and Google are releasing 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 mainly limited to Samsung. Vizio and Hisense produce TVs that support both, but not all, models. There are also very few movies that are mastered in HDR10 + and only Amazon produces streaming content for it.
Because HLG is a broadcast standard, most modern TVs will support it going forward. However, your screen does not have to support HLG for you to receive broadcasts. If you do not watch a lot of network TV or cable, you can put HLG low on your priority list.
In most cases, the TV you choose will dictate the standards you can enjoy. With that in mind, you also want to understand the difference between display technology so that you can make an informed choice.