Everything you need to know about 4K and UHD
The world of TVs has moved on a lot in the last year. There are new technologies and certifications, all aimed at helping TV tech take the next leap forward. They all carry snappy acronyms like HDR and BT.2020. The one you need to look out for is '4K'.
There has been talk of 4K for years, but it's no longer just something for the tech-minded early adopters. This advancement has properly hit the mainstream. It is now an important new standard.
How important? Netflix has been hard at work pushing 4K for over a year. The new Sky Q box will push 4K to a whole new segment of mainstream TV viewers in the UK. Amazon's latest Fire TV provides another accessible entry point to UHD content. Then there's the new Xbox One S, which brings the 4K love-in to games too.
At CES 2016, all the big manufacturers like Samsung to Panasonic unveiled new 4K TVs. Most of them are have the new Ultra HD Premium certification, which you can read all about in our helpful guide: 'What is Ultra HD Premium?'
With all that in mind, we thought we'd have a crack at compiling an ultimate guide on 4K. Here are some of the most common 4K-related questions, to save you a load of time and effort when buying a new TV.
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Q: What exactly is 4K?
A: 4K, also known as Ultra HD, refers to a resolution of 3840x2160 pixels. That's four times the 1920x1080 pixels found in your full HD TV.
Q: What is the difference between 4K and Ultra HD?
A: While 4K is the more commonly used term, some brands prefer to call it Ultra HD, or UHD for short. Technically, there is a difference.
Used correctly, 4K describes the 4096x2160 resolution first introduced in digital cinemas. UHD refers to the 3840x2160 resolution you'll find in 16:9 ratio TVs, which is what you actually take home.
That means 4K is the wrong term for 3840x2160 displays and content, but it is used so often that the distinction has been all but lost. For most people, the two terms are interchangeable.
Q: Is 4K actually any good?
A: While 4K has its detractors, we’re big fans. The extra resolution of 4K images adds better definition and clarity to the picture. The result is images that look incredibly life-like, more like looking through a window than watching TV.
4K is especially effective on very large screens – so ideally you’ll go for a 65-inch set or even bigger. That said, we’d argue that 4K resolution clearly improves picture quality at pretty much any screen size. The effect is more noticeable if you're moving to 4K from a TV of the same size. Let's say you have a 50-inch HD TV and you upgrade to 4K: you are cramming four times the number of pixels into the same amount of space. That makes for a noticeably denser picture with finer detail.
Don't just take our word for it: 4K is considered by the film-making community as being able to reproduce the sort of resolution and ‘finish’ you get with 35mm film.
Some film studios are even talking about 8K, and LG showed off its first 8K TV at CES 2016. That's overkill, and this standard won't attain mainstream acceptance (or affordability) any time soon. You're safe to go ahead with your 4K TV purchase.
Q: Do I need to sit nearer my TV to benefit from 4K?
A: To get the best from 4K, it is recommended that you sit closer to your screen than you would with with HD TVs. The extra resolution and increased pixel density means you can sit further forward without spotting individual pixels. And filling up more of your field of view makes for a more immersive experience.
There are ‘scientific’ charts in circulation suggesting that you must sit extremely close to appreciate the extra resolution at all.
While we’d agree sitting close gives you the most impact, we reject the notion that you get no benefit at all from more distant viewing positions. You still perceive more depth, colours still look more smoothly rendered, and objects within the picture still look more solid and three-dimensional.
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4K packs in four times the number of pixels as Full HD / 1080p.
Q: Is a 4K TV all I need to start watching 4K?
A: No. While your 4K TV will use processing to upscale HD and standard definition pictures to its 4K pixel count, you will still want a native 4K source.
Q: What 4K content can I watch?
A: Until recently the short answer to this was ‘not a lot’. Then answer became 'not a lot but there's more coming soon'. Now there is plenty of 4K content.
The most important 4K option is Netflix. The subscription on-demand service currently carries a growing library of TV series and films you can stream in 4K for £8.99 per month (up from £5.99). In terms of TV, Breaking Bad and House of Cards have been joined by the likes of Marco Polo and The Blacklist. UHD films include The Amazing Spider-Man, Crouching Tiger Hidden Dragon and Jerry Maguire, among others. You also get a few nature documentaries.
Amazon Prime Instant Video also offers some 4K content free of charge, including original Amazon series Mozart in the Jungle, Extant, and Transparent, though only on select TV sets from Sony, LG and Samsung.
Otherwise your main source of 4K content is the internet, predominantly via YouTube and a handful of dedicated 4K sites such as hd-trailers.net and demo-uhd3d.com. You can download files from these, transfer them to USB drive, and play them directly into your TV (so long as your TV is compatible with the video encoding format of the clip you want to watch).
BT has also has a 4K channel - BT Sport Ultra HD. As the name suggests, this is a sports channel (read further down for more information about sports) and it shows Premier League, FA Cup and Champions League football along with Aviva Premiership rugby. You'll need one of BT's Ultra-HD boxes to take advantage of the service though.
There are a couple of other boxes too that'll help fill your screen with glorious 4K. The most notable is the Android TV toting Nvidia Shield. This box will stream 4K Netflix and retails for £149. Amazon also do a Fire TV 4K box for £79, though it's not very good.
Last October, Roku announced a new 4K-capable streaming box of its own. The Roku 4 has launched in the US but isn't out yet in the UK, although it should be along soon, and it'll cost you £100. The company also announced a new 4K TV which will debut later this year.
Finally, Sky's Sky Q Silver box and Sky Q service. This box lets you view 4K content, which Sky told TrustedReviews will mostly be sports and movies – and record them too. The 4K content was unavailable at launch, but that's now changed. Expect a full review of that shortly, but for now here's a hint: it looks lovely. For a breakdown of how much Sky Q will cost, check out our Sky Q Price feature.
LG launched the 65G6 4K OLED TV at CES 2016
Q: Do all 4K TVs support 4K streaming?
A: No, not all of the older ones do. None of 2013’s 4K TVs can handle Netflix’s 4K streams, due to them not being able decode the HEVC video format Netflix has adopted. Not all of 2014’s 4K TVs can handle Netflix 4K either, with sets from Philips and Toshiba unable to cope with Netflix 4K (Panasonic added such support for its AX802 range late in the year).
The majority of 4K TV sets from reputable manufacturers released in 2015 support Netflix 4K streaming, however, so if you've bought one recently you should be okay. The 2016 TVs are the first batch of TVs where 4K support is prevalent.
Philips (a manufacturer that hasn't been great with Netflix 4K support) also supplies the UHD 880 4K, a media streamer that adds such support to its non-compatible TVs. Sony has one too in the Sony FMP-X5, which can enable Netflix 4K streaming on older Sony 4K TV sets for around £350.
Indeed, Sony is one of the biggest supporter of 4K so far, with an available library of a couple of hundred 4K films.
It must be stressed that not being able to play Netflix 4K doesn’t automatically preclude a TV from being able to play future alternative 4K streaming services that might emerge. But it doesn’t exactly fill us with confidence…
Q: What broadband speed do you need to stream 4K?
A: Netflix and Amazon are the big names streaming 4K, and both services need a minimum of 15Mbps to do 4K. And your speeds need to remain consistently at or above that figure. As soon as you drop lower – due to high contention rates at peak usage times, say – the picture will slip back into HD mode. And don't worry if you start off with a blurry image: it's quite common for streaming services to start a programme at a low resolution and then bump it up to HD and UHD after the initial buffer.
To try and cover itself for this eventuality, Netflix actually says on its website that you need 25Mbps minimum. But we’ve confirmed with Netflix that a consistent 15Mbps is enough. It's worth bearing in mind that this means you need 15 to 25Mbps of spare bandwidth, so if someone else is using your Wi-Fi, you'll need to have that amount of bandwidth free after you account for the other person's usage.
Compression techniques improve all the time, so it’s possible you may in the future need slightly lower broadband speed to experience 4K on Netflix or other rival 4K streaming platforms. But bear in mind that high levels of compression inevitably negatively affect picture quality, so if you’re serious about 4K a fast broadband connection is a must.
House of Cards was the first 4k series available made available to stream, via Netflix.
Q: What is UHD Blu-ray and when is it coming out?
A: We've got a detailed breakdown of UHD Blu-ray which you can check out for a full rundown of the new format. In short, Ultra HD Blu-ray discs have a much larger capacity than standard Blu-ray discs, and as such can carry the information needed to store 4K video.
CES 2016 saw several new Ultra HD Blu-ray players announced, including Panasonic's DMP-UB900. Then came the Samsung UBD-K8500. Sony has yet to announce its own challenger, but Microsoft provides an affordable alternative in the Xbox One S, which plays 4K Blu-rays alongside games.
The discs will certainly cost you, as confirmed by the recent news that UHD Blu-rays could go on sale for as much as £30 for new releases.
Q: What connections do I need to watch 4K?
A: We’d love to say ‘an HDMI socket’ and leave it at that, but wouldn’t you know it, it’s just not that simple.
The issue here is that not all HDMI sockets are equal. There have been multiple versions/standards of HDMI since the digital connection first appeared, with the latest v2.0 HDMI specification being defined specifically with 4K feeds in mind.
The most significant advantage of v2.0 HDMIs from a 4K perspective is that they support increased data bandwidth, and so enable playback of 4K feeds with full (so-called 4:4:4) colour sampling at frame rates of up to 60fps. The previous v1.4 HDMIs only support 4K feeds up to 30fps.
HDMI sockets made to the v2.0 level have only really entered the TV manufacturing stream last year. Some older 4K sets were able to upgrade their v1.4 HDMIs via firmware to permit 4K streams at higher than 30fps frame rates, but only with reduced colour sampling.
Most of the major 4K TV brands now carry HDMI 2.0 in their current TVs – LG, Sony, Panasonic and Samsung are all onboard with it now, as is (finally) Philips.
Content mastered with High Dynamic Range (HDR) will be a big TV feature which you will see more and more of in 2016. HDR is a term to describe a series of trends which allow for pictures with vastly improved contrast and colour. In order to accomodate this, HDMI 2.0a was devised. This is not a connection change, so your current HDMI changes will still work and most TV manufacturers have said they can upgrade their products to HDMI 2.0a with a firmware update.
With all this in mind it’s easy to understand why Samsung has opted to go with an external ‘One Connect’ connections box for its flagship UHD TVs, since these can be upgraded in future years as connectivity requirements change.
Because of the ongoing TV connection issues, don't rule out seeing more of those external 4K ‘receivers’ able to decode 4K streams and even download 4K titles on your TV’s behalf.
Q: Can I make my own 4K content?
A: Indeed you can. There are now domestic cameras out there capable of producing startlingly good 4K quality without costing the earth. Two of the best examples are the £1,500 Sony FDR-AX100 camcorder and the similarly priced (with lens) Panasonic DMC-GH4 camera.
Many modern smartphones are also capable of capturing 4K video, including Apple's iPhone 6S and iPhone 6S Plus. Of course, 4K recording has long been supported at the top end of the Android market, and current flagships such as the Samsung Galaxy S6, HTC One M9, and the Nexus 6P.
Want the ultimate in sound quality as well as a 4k picture? The Sony KDL-65X9005B set the standard.
Q: When will more commercial 4K content become available?
A: The good news is that more and more films and TV shows are now being made in 4K. So the source content is at least being created. It’s just a pity that distributing it seems so difficult. With the arrival of UHD Blu-ray, and the increasing sophistication of Netflix and Amazin Video, we already have a lot more 4K content than we did this time last year.
What of 4K broadcasts? The BBC continues to test its own UHD broadcasts, but still doesn't feel that enough 4K TV sets are out there to justify a more meaningful push.
On a more positive note, Sky's 4K capable box Sky Q is now available, and 4K content has arrived. BT, for its part, has already released a 4K-capable box, which runs its BT Sport Ultra HD channel and Netflix 4K.
Other 4K options include the likes of the Ultraflix service. Launched in the US a year or so ago, and available across a number of 4K TV brands (including Sony and Samsung), it offers hundreds of hours of 4K content containing a mix of sports, concert, documentary and film. It's not the most polished or comprehensive of offerings, however.
One final potential 4K source to look out for are external HDDs, to which you can download 4K films. These are likely – in the short term, at least – to be offered as add-ons to specific brands of TV. Sony has had such boxes available for purchase with its 4K TVs in the US since 2013, offering a series of preloaded titles and the facility to download other titles later.
Samsung has launched a similar box in the UK. The UHD video pack offers owners of Samsung UHD TVs (it won’t work with other brands of TV) three pre-installed 4K movies and a bunch of demo material for £150.
Q: What's this about older 4K TVs not being able to handle sport?
A: Yes, about that. As is probably becoming eminently clear to you by this point in the article, anyone who became an early adopter of the 4K standard is, well, a little screwed. The constantly shifting goalposts of this new standard have rendered 2013 sets all but obsolete, and that's particularly the case if you watch a lot of sport.
Because early 4K TV sets can only render UHD content at 25fps, they won't be suitable for future 4K sports broadcasts. At least, not on Sky's service anyway.
Speaking at a conference in London last year, Sky's Chris Johns supplied the brutal truth: "If you bought a [4K] set in 2013 and early 2014, then sorry, it won't do sport. It'll only go up to 25 frames per second."
25fps is just peachy for most Hollywood films, which are shot at that frame rate. But sporting broadcasts benefit from the smoother action that much higher frame rates bring about, with 100fps here stated as the ideal.
Such a boost in frame rate requires newer, faster hardware - a software update simply won't cut it. Hence the reason that your 2013 or even 2014 4K TV might not play future sporting content.
Samsung is one company that has provided a way out for 4K early adopters, but it involves plugging yet another box into your TV set. The UHD Evolution Kit costs around £400, and essentially acts as a hardware upgrade complete with quad-core processor and HDMI 2.0 connectivity.
It sucks for the early adopters, but that's generally the risk you take for getting on in Phase One of any new tech. The good news is that the dust is finally settling, and there are standards in place. If you buy a big-name 4K TV right now, you're unlikely to be stung.
Additional reporting by Joe Roberts and Jon Mundy