Every few years, manufacturers come up with a whole bunch of new tech, most of which has a confusing acronym. UHD and 4K. HDCP. OLED. (Indeed, our laptops' Caps Lock keys have been subject to considerable wear over the last few years.)
And the latest? HDR. But what is it and how will it make your video pictures look better than ever? Read on for all you need to know about HDR video technology on 4K TVs, games consoles, mobile phones and more...
What does HDR mean?
‘HDR’ stands for High Dynamic Range, and it is the next big thing in the video world when talk turns to 4K TVs and 4K content. The term originates in photography, and refers to a technique that heightens a picture’s dynamic range – the contrast between the brightest whites and the darkest blacks.
The theory is: the higher the dynamic range, the closer a photograph gets to real life. HDR for televisions is basically the same idea.
Look out of the window. Look at the sky. The clouds may be white (or grey, if you’re in the UK) but there should be definite layers, and around the clouds you should be able to pick out varying degrees of brightness.
Now look at clouds in any film on your TV. They tend to look flat by comparison, with white levels crushed and layers virtually indistinguishable. There are several reasons for this.
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What's so good about HDR?
The first reason is your TV’s limited dynamic range, its inability to illustrate the finest differences in brightness. This means you miss out on all the nuance that really ought to be there.
After all, your eyes can differentiate a lot more information than your telly feeds you. Then there’s all the processing that takes place along the chain after something is filmed.
It dramatically reduces the amount of information transferred in order to match the technical limits imposed by your TV.
Lately, though, TVs have become much more capable. And by that, we mean bright. A normal TV puts out around 100-300nits of brightness, where one nit (derived from the Latin for ‘to shine’) is equivalent to the light provided by one candle. An HDR TV can in theory deliver up to 5000nits.
Of course, that sort of light would be blinding at maximum brightness. This tech isn’t about searing your retinas, though - it’s about widening the range in order to display finer increments of shading.
The idea is to let you see more of what is recorded. You’ll get more details in the shadows and highlights. Sunlight will gleam properly off windows. Colours will be richer and more lifelike, with more delicate gradations and greater shifts in tone. Basically, your picture will look more natural and more real.
Don't believe us? Take it from Hollywood colourist, Dado Valentic, in our video below...
What is HDR10?
Currently, there are five different varieties of HDR: HDR10, HDR10Plus, HLG, Dolby Vision, and Advanced HDR by Technicolor.
HDR10 is the original and currently most common form of HDR. It's an open standard that has been adopted by numerous manufacturers, service providers (Amazon and Netflix) and the Blu-ray Disc Association (BDA).
According to the CEA (Consumer Electronics Association), HDR10 must meet certain standards, including 4:2:0 colour sub-sampling, 10-bit bit depth, and the BT.2020 colour space.
What is Dolby Vision?
As previously mentioned, Dolby has its own version of HDR: Dolby Vision. This was initially an initiative for its Dolby Cinemas, combining HDR video with Dolby Atmos sound, in an attempt to take on IMAX cinemas - but Dolby Vision can also be adapted for the home.
The key difference between Dolby Vision and HDR10 (besides the fact Dolby Vision requires payment of a licence fee) is the former allows for dynamic metadata to be added to a vanilla HDR image. In theory, this allows for an improved image on a scene-by-scene basis - while HDR 10 works its magic film-by-film.
Both HDR10 and Dolby Vision can feature on the same TVs and discs, although Dolby isn't yet quite as ubiquitous. The recent release of Despicable Me and its sequel marked the first Ultra HD Blu-rays with Dolby Vision, and others such as Power Rangers, Baywatch and Blade Runner 2049 are following.
The two formats can happily coexist (Amazon Prime Video and Netflix offer both), although you will need a Dolby Vision-compatible disc, Blu-ray player and TV all capable of processing it before you can enjoy the technology at home. LG has so far been the format's biggest adopter on the hardware side, with many of its 2016 LCD and OLED TVs, and the whole of its 2017 OLED line-up supporting it. You can find a more comprehensive list of supported products by following the link below.
More after the break
What is HDR10+?
Samsung has decided to make the TV world all the more confusing by developing its own standard of HDR: HDR10+.
Just like Dolby Vision HDR, Samsung's tech uses dynamic metadata in compatible content to boost HDR images scene-by-scene - and even frame-by-frame.
Samsung doesn’t support Dolby Vision on any of its TVs, and it’s not a stretch to say its system is a direct rival to Dolby’s.
Amazon Video is the first content provider to announce support for HDR10+, and is aiming to deliver compatible shows in 4K HDR10+ by the end of 2017.
All of Samsung’s 2017 4K TVs have HDR10+ support built in, while a firmware update will make it available to existing 2016 4K TVs later this year.
It's not taking on the HDR world alone, however, sensibly recruiting support from other industry players. In a bid to bring the format to more hardware, it recently announced a partnership with Panasonic and 20th Century Fox to start licensing the HDR10+ platform early next year. So watch this space.
The HDR format’s metadata will be licensed to manufacturers of TVs, digital TV boxes and Blu-ray disc players, as well as content companies. It will be an open, royalty-free platform and, naturally, will be associated with its own certification and logos.
What is HLG?
HLG (Hybrid Log Gamma) is potentially the most important HDR format of all. Why? Because it's going to be used with TV broadcasts.
It's the result of a joint research project between the BBC in the UK and NHK in Japan, and is designed to deliver a more convenient HDR solution for the broadcast world than HDR10.
It takes standard dynamic range and high dynamic range images and combines them into one feed, with HLG-compatible 4K TVs able to decode and show HDR images in all their glory.
Most big-name manufacturers have confirmed their 2017 sets are HLG ready, with Samsung, Sony and LG also confirming their 2016 HDR TVs are receiving HLG support via firmware update. Panasonic is also offering the same for select top-tier 2016 models, too. The framework is in place, we just have to wait for the content to come...
What is Advanced HDR by Technicolor?
Advanced HDR by Technicolor is a newer HDR format, launched at CES 2017. It's the result of collaboration between LG and Technicolor, the video specialists.
As with the other types of HDR, the content needs to be mastered in the format, played back by a source that can read the Advanced HDR data and then displayed by a compatible television or projector.
There's no official word on any upcoming content that's been mastered in Advanced HDR by Technicolor, although a number of LG's 2017 TVs (both 4K OLED and LCD) are compatible with the format.
HDR and 4K Ultra HD
LG's 65EF950V OLED TV is fully compatible with HDR content
HDR should not be confused with the other big TV buzzword of the moment: UHD (Ultra High Definition), also known as 4K. Both HDR and UHD are meant to improve your viewing experience, but they are hugely different technologies with almost no overlap.
It’s a matter of quantity and quality. UHD is all about bumping up the pixel count, while HDR wants to make the pixels you have more accurate regardless of how many there are. Whether you’ve got a 32in unit in the bedroom or a 75in monster in the living room, HDR could make a visible difference.
Of course, while UHD and HDR are different technologies, they can still work together. The vast majority of HDR-compatible TVs on the market are also 4K Ultra HD TVs, although Sony does have a 2017 range of Full HD TVs that also support HDR.
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How can you watch HDR?
To benefit from HDR10 or Dolby Vision, you’re going to need a few things. The first stop is your display. Whether you’re after a television, a projector, a mobile phone or tablet, it needs to be HDR-compatible.
LG, Samsung, Sony and Panasonic all have their own HDR TVs - chances are your next 4K TV will support the format. Some of the best HDR TVs we've reviewed include the Samsung UE49KS8000, LG OLED55B7V and Sony KD-55A1.
This is a small point, but don't confuse normal HDR with picture processing modes such as HDR+ or HDR Effect. These are modes (used by Samsung and LG respectively) that claim to create HDR-quality images from non-HDR content.
The next step is to get something to play it on. If your HDR content happens to be on a disc, i.e. an Ultra HD Blu-ray, you're going to need an Ultra HD Blu-ray player to play it on. Our current favourites are the Panasonic DMP-UB900, Sony UBP-X800 and Oppo UDP-203, but Microsoft's Xbox One S and Xbox One X also play 4K Blu-rays and include HDR10 support. Sony's PlayStation Slim and PlayStation 4 Pro aren't 4K players - but they are compatible with HDR10 content, including games.
Alternatively, perhaps you're streaming HDR content via Netflix or Amazon Prime Video - both services support HDR10 and Dolby Vision. This can be done through a compatible app on your TV or streaming box, such as the latest Amazon Fire TV or the new Apple TV 4K. (The latter will also offer 4K HDR films through Apple's iTunes service.) For that, you’ll also need an internet connection with the appropriate bandwidth.
HDR on the Xbox One S, One X and PS4 Pro
The Xbox One S not only has an Ultra HD Blu-ray player, it also supports HDR video. You'll need a TV that supports HDR10 to view HDR content from the Xbox One S.
Provided HDR is supported on your TV (and turned on), then both consoles can output HDR video from any compatible source - Ultra HD Blu-ray discs, HDR streaming services and HDR games.
The first Xbox One S HDR games are already here - titles that support it include Battlefield 1, NBA 2K17, Forza Horizon 3 and Gears of War 4.
While the new PS4 Pro launched without a 4K Blu-ray drive, it does support games that have been optimised for HDR such as Uncharted 4: A Thief's End and Deus Ex Mankind Divided.
What about mobile HDR?
The ill-fated Samsung Galaxy Note 7 was the first HDR smartphone. Since then we've seen the LG G6, Sony Xperia XZ Premium, Samsung's Galaxy S8, Galaxy S8+ and Note 8 and Apple's iPhone X launch with HDR.
There's also more mobile-optimised HDR content, with both Netflix and Amazon Prime Video now streaming HDR content through their mobile apps. Netflix's HDR offering is now compatible with the smartphones listed above (save for the Samsung Galaxy handsets), as well as the new iPhone 8 and iPhone 8 Plus. YouTube has also updated its app to bring HDR to select Android phones, including the Galaxy S8, Note 8, Google Pixel, LG V30 and Xperia XZ Premium.
The UHD Alliance - the organisation that sets standards for Ultra High Definition content - has also set the minimum spec for 4K phones and other portable devices showing HDR content.
Called Mobile HDR Premium, the standard is essentially a certification for smartphones, tablets and laptops that meet minimum standards in terms of resolution, dynamic range, colour space and bit depth - i.e. you're guaranteed a certain level of experience when watching 4K HDR content. The label will also be applicable to 4K HDR content optimised for mobile devices.
The Samsung Galaxy S8 and Galaxy S8+ were the first smartphones to officially be given Mobile HDR Premium certification.
What HDR content is available?
HDR content is filmed or mastered in HDR – playing ordinary footage on an HDR TV alone won’t cut it. Amazon Prime Video was the first service to stream ‘HDR’ footage, but Netflix also has its fair share of HDR content including Chef's Table, Marco Polo, Marvel's Daredevil and Marvel's Jessica Jones.
With the launch of the Apple TV 4K, Apple is also gearing up to offer 4K HDR films through iTunes. The best part? They won't be any pricier than their HD equivalents, and any HD films previously purchased through the service will be upgraded free of charge. As it stands, 4K films on the service will be stream-only, so users won't be able to download them.
On top of streaming there’s the Ultra HD Blu-ray format, which includes HDR10 in its base specification and is now supporting Dolby Vision too. 4K Blu-ray discs are on sale now, with more and more titles being launched every month.
The future of HDR
There's no denying HDR is a very attractive idea. And when we've seen it in action the results - on the whole - have been impressive.
The combination of 4K and HDR on a TV means a super-sharp, super-dynamic picture – and a clear step-up from the HD most of us have come to know and love.
HDR content will continue to hit the mainstream via streaming services and Ultra HD Blu-ray, which combines Ultra HD with HDR on one disc. For many enthusiasts, this could be the complete AV package.
2017 has certainly been the year HDR has become a reality for more consumers, and it's something that should definitely be considered when upgrading your current TV. The only potential flies in the ointment are the different flavours of HDR and the need to ensure your TV is future-proofed for when/if the different variants go mainstream. At the moment, we'd ensure yours has HDR 10 and Hybrid Log Gamma as the bare minimum.
Now consumers have access to the displays, the sources and the content to complete the HDR chain, the current (and future) play of video is in a very good place indeed. Nope, HDR isn't going anywhere. And nor should it.
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