Our televisions are evolving rapidly. Last year saw a lot of noise about 4K resolution (also known as Ultra HD or UHD) and the emergence of ultra-thin OLED screens with darker blacks for increased contrast and more vibrant images.
More recently, another acronym has reared its head: HDR, which stands for high dynamic range. This new standard – designed to further improve the colour space and contrast that can be achieved – has been heralded by manufacturers as a big leap forwards in image quality. More and more, the ‘4K UHD’ designation on devices is being replaced with ‘4K HDR’ – but does this new standard genuinely represent a substantial improvement, or is it just another way to get consumers to part with their hard-earned cash?
What does HDR do?
While 4K UHD significantly boosts the number of pixels that are displayed on a screen, HDR enlarges the dynamic range of the image, accentuating the contrast between dark blacks and light whites. This introduces more subtlety into the picture you see, with more vivid colours and extra nuances visible when compared to a standard display.
While it is widely accepted that 4K UHD can look incredible on a huge movie theatre screen, it will be noticeably less impressive on a 55” screen from 10’ away (this being the typical viewing distance of an average living room). However, 4K with HDR offers the best of both worlds: increased resolution is paired with higher contrast and colour depth, achieving a balance that will make watching your TV at home a much more vivid, detailed experience, no matter the screen size.
But wait, aren’t there different kinds of HDR?
This is where, for most people, the confusion comes. While HDR does have an open-source standard already established, this is not the only protocol out there. In fact, there are four: HDR10, Dolby Vision, Hybrid Log-Gamma (HLG) and Technicolor Advanced HDR. While this slightly complicates things, there isn’t too much for consumers to worry about, as only the first two standards are in common use – and even then these are largely interchangeable.
HDR 10 is the de-facto open standard for high dynamic range, developed by the Consumer Electronics Association (CEA) with input from several of its partner manufacturers. This standard defines the minimum colour space, bit depth and colour sub-sampling that needs to be achieved for a screen, player or film to qualify as offering HDR. While it is hardly a hugely exacting standard for manufacturers to aim for, it has been adopted as the default for 4K UHD Bluray and also for the PS4 and Xbox One S, making it a solid benchmark for devices offering HDR support.
Dolby is well-known for its success in establishing proprietary standards across almost every aspect of home entertainment. Dolby Vision, which features dynamic metadata and higher quality requirements than HDR10, is the company’s latest attempt to establish dominance over the protocols surrounding screen contrast and colour definition. This standard is designed to be more future-ready, in that its maximum range is beyond that which current screens are able to achieve.
Its major initial drawback was the insistence that all HDR hardware would need a dedicated chip in it, although now Dolby has announced that Dolby Vision is now wholly software-based, making it compatible with many existing 4K televisions via a firmware update.
Hybrid Log-Gamma (HLG)
This format, co-developed by the BBC and Japanese broadcaster NHK, is a version of HDR designed to be used for live video streams. Unlike Dolby Vision or HDR10, it doesn’t require metadata descriptions to be sent along with the image; instead it sends information to the screen about how to enhance the image on a scene-by-scene basis.
While it is not yet widely available, it is being built largely upon existing standard definition resolution (SDR) infrastructure, so it’s unlikely that TV owners will need to worry about whether their screen will be compatible once this becomes available.
Technicolor Advanced HDR
Technicolor’s version of HDR is much more geared towards cross-compatibility – its broadcast distribution system adjusts images locally for SDR or HDR, as well as up-scaling SDR video to HDR. Like Hybrid Log-Gamma, this version of high dynamic range isn’t common yet, although manufacturers such as LG have announced that their latest TVs will be able to support both of these formats.
Is there actually any content for HDR?
In line with the widening appeal of 4K UHD content, HDR movies and TV programmes are being released at a steady rate. Dolby Vision, which has been backed by all of the major film studios, is slated to be included in 100 UHD Bluray films by the end of 2017, while Netflix is aiming to have more than 150 hours of HDR content available on its streaming service by the end of the year. Amazon Video also supports HDR, although both of these streaming platforms suggest that an internet connection of at least 15 Mbps is needed to play HDR content smoothly.
Neither SkyQ or Apple TV support HDR content in any format, although the latter is rumoured to be including this in its 2017 model. Notably, the new Virgin TV V6 box does support HDR content, giving it a unique advantage over Sky at this point in time.
When it comes to gaming, Microsoft and Sony have both announced HDR-compatible titles for their Xbox One S and PS4 consoles, although there are only a dozen or so games released for each console at time of writing. More studios are beginning to embrace this format, so expect to see this list of games with HDR support growing as the year progresses.
How do I know if my hardware will support HDR?
Most screen manufacturers are now releasing screens that support high dynamic range, but to-date only LG has openly said its screens will support all four standards. While all of the major screen makers have embraced HDR10, Samsung and Panasonic are still dragging their heels when it comes to adopting Dolby Vision for their devices, potentially balking at needing to pay Dolby a license fee to use its technology.
When it comes to Bluray players, only those supporting UHD Bluray will be able to handle this type of content. The choice in this area was, at first, incredibly limited – although now there are devices available from the likes of Panasonic, Oppo and Samsung (while the Xbox One S also niftily doubles up as a UHD Bluray player).
Currently, HDR is only available for premium screens and players, making it a more expensive option than a standard HD flatscreen and Bluray player. That said, the improved image quality offers a substantial upgrade to your home entertainment.
Prices for 4K UHD screens with HDR built in have fallen significantly from their initial lofty peak, to the extent that a 55” screen can be sourced for somewhere in the region of a few thousand pounds, although higher-specification sets will cost more than this.
With 4K HDR establishing itself the de facto standard for premium home entertainment, having an HDR-enabled screen and player is fast becoming a must-have addition to the home.