4K, Ultra HD, 4K Ultra HD – call it what you want – the 'four times HD' TV technology finally arrived with some purpose in 2013, with more 4K TVs, the first broadcast trials and even some content.
We have now seen the next generation of UHD TVs from the likes of LG, Panasonic, Samsung and Sony for 2014 revealed at CES, plus a number of budget 4K TVs. And there's news of more 4K content, from Netflix 4K to plans for the football World Cup.
So, what's it all about? On this page we'll run through the basics, get you up to date on 4K TVs and 4K content, take a look at the 4K Ultra HD TVs on the market – and how the sizes and prices are coming down (if you're not brand
You will also find a round-up all of our 4K TV reviews to date. We'll be keeping this page updated as your one-stop for everything 4K Ultra HD, so check back if you're in the market to buy a 4K TV...
MORE: Best 4K TVs of CES 2014
4K TV resolution
Officially 4K resolution is 4096 x 2160 pixels. However, in order to shoe-horn this higher resolution video on to a normal 16:9 picture format for a TV, the resolution has been altered to 3840 x 2160 – still four times the total number of pixels on a Full HD 1080p screen (1920 x 1080).
In order to take full advantage of 4K Ultra HD you will of course need a compatible TV, source and the necessary content packing those all-important extra pixels. And that's where it gets messier: while we're seeing the first 4K TVs going on sale, the issue of content – when we're going to get it, how we're going to play it – is much trickier.
There's no denying that 4K Ultra HD is very much a fledgling format. Native content is very hard to come by for consumers anywhere.
In 2014, it looks like we can look forward to streaming 4K video from Netflix, with House of Cards: Season 2 making history as the first 4K streaming content from the service, and Breaking Bad in 4K set to follow later in 2014.
However, you will need to have a new 4K TV with the HEVC codec that Netflix is using in order to play the content.
Sony and Netflix have struck a deal, which means it could be Sony TVs that get the best out of Netflix first.
YouTube 4K was also demoed at CES 2014, using a new codec that cut the data used by the current option by half.
Other options? If you're in the US, there's the Sony 4K Ultra HD Media Player, which went on sale in July 2013 for $700.
The FMP-X1 server comes pre-loaded with ten 4K films, has a 2TB hard drive, HDMI and USB connections and connects to your network via an Ethernet connection.
And it sounds like you'll need that wired connection for accessing Sony's 4K download service. Officially called Sony Video Unlimited 4K, the download service is live in the US and promises to be the world's first and only network service to give access to a constantly updated library of 4K films and TV shows.
The downside? There are currently "no plans" for a UK release. We suspect rights issues are the problem, or perhaps Sony is just waiting until the time is right. We shall see.
As for the cost of this 4K content, a single film looks like being $7.99 for a 24-hour rental or $30 to buy. Not cheap, then.
In more positive news, 4K broadcasts remain on the to do list, with Sony promising to provide technical support to 4K productions, including the 2014 FIFA World Cup.
There's also the outside bet that Sony will enable 4K video on the PlayStation 4 with a firmware update, allowing far more people to access Ultra HD video. We shall see.
Getting 4K films on to disc looks like being a trickier business with no official specification nailed down and no immediate plans.
In fact, Netflix chief product officer Neil Hunt reckons you'll never get Ultra HD 4K video on disc. Though, yes, he would say that.
"The cost and effort of building a whole new disc format and putting that together for the relatively small number of people who'll have a device in the short term isn't going to happen," according to Hunt.
Reports have suggest that a triple-layer 100GB optical disc is in production, which could theoretically find room for 4K films, but there's been no further information on this.
Sony is instead pushing its "Mastered in 4K" Blu-ray discs.
There are now 20 titles in total, including The Amazing Spiderman, Total Recall (2012), Ghostbusters, Battle: Los Angeles, The Karate Kid (2010), Taxi Driver, Angels & Demons, Glory, The Other Guys, Spider-Man (2002), Godzilla, Men in Black, Moneyball, Spider-Man 2 and Pineapple Express.
It's important to remember these aren't "4K Blu-rays" as such, rather movies that have been filmed in 4K, scanned in 4K and then downscaled to 2K (1080p) to fit on a standard Blu-ray.
4K Ultra HD TV prices
Big-hitting brands such as LG, Samsung and Sony may be leading the charge, but the company's 4K TV sets still come in at eye-wateringly large prices. The Sony KD-65X9005A was the first of the almost affordable high-res TVs that we've reviewed, but at £6000, it still ain't cheap. The Philips 4K TV, at £4500, has since taken that crown.
Samsung's UE55F9000 and UE65F9000 4K sets are now on sale in the UK at £4000 and £6000 respectively, matching the prices of Sony's same-size models.
However, smaller and, crucially, more affordable brands such as Seiki will be just as important when it comes to bringing 4K Ultra HD TV to the masses. A 39in Seiki 4K TV recently went on sale for $699 in the US, hot on the tail of a 50in for $1500.
CES 2014 saw budget 4K TVs announced by Kogan and Polaroid, with prices for 50 and 55in sets starting at around $1000, potentially around £600.
As demand grows – and the signs are positiive – production costs should drop, and in turn we should see more affordable big-screen 4K sets from the likes of LG, Panasonic, Samsung (below) and Sony.
4K TV news
CES 2014 saw a whole host of brand new 4K TVs announced from LG, Panasonic, Samsung and Sharp.
The biggest news was that Ultra HDs are now available in 'bendy'. Yep, flexible TVs were perhaps the strangest thing to appear at CES, with both LG and Samsung revealing bendy TVs, showing-off 77in and 105in flexible 4K TVs respectively.
Of course getting all those new products to market, and especially the UK market, is often a different story. Sony has fulfilled that promise, with the 55in and 65in Sony X9 Series TVs now on sale, while the 85in Samsung 4K TV, on sale in the UK, has been joined by 55in and 65in models in Korea.
Talking of OLED TV, it seems with a worryingly low yield for OLED panels – only 1 in 10 is good enough to use – means Samsung seens to be focusing its attention on 4K TV screens for now, instead of OLED. It'll be interesting to see if trend is replicated by other brands.
Apple 4K TV
The Apple iTV has been rumoured longer than many of us can even rememeber (well, a few years at least) and after rumours of a TV with AirPlay and Siri, or even an OLED Apple TV, the latest rumour is of a 4K Ultra HD Apple TV.
We're not sure how much weight to attribute to the analyst behind the rumours but certainly a panel built in cooperation with LG and Samsung sounds believable, and certainly the 55in and 65in sizes are the most common for 4K TVs at the moment. We shall see.
4K TV: broadcasts
What about watching live TV in 4K resolution? Well, like the film content: they're working on it.
In August 2013, Sky carried out its first ever live 4K trial broadcast using the English Premier League match between West Ham and Stoke City.
The BBC and Sony also trialled 4K Ultra HD broadcasts at the Wimbledon 2013 tennis tournament, with a Sony "4K Experience Zone" showing what the future of live sport on TV could hold. Having worked together on 3D broadcasts, Sony is supplying 4K cameras and engineers in order to test out getting 4K from camera to TV.
The BBC and Sky are also part of the new UHD-Forum, which has been formed to promote 4K TV and is led by the Digital TV Group. The forum's aim is to avoid the confusion that emerged when HD TV and HD-Ready TVs first came on sale. Sky 4K content is also very much on the 'to do' list, with the company stating it has looked at trials.
Meanwhile in Japan, telecoms company NTT West has already trialled streaming 4K TV content over the internet, using new compression technology to send the hi-res pictures to set-top boxes. Reports suggest that Japan plans to broadcast the 2014 World Cup, which takes place in Brazil, in all its 4K glory to viewers in Japan.
A number of TV shows, including the cult series Breaking Bad, are already being filmed in 4K. The breadth and depth of content is building it's just the mediums for watching it that need to be ironed out.
4K TV reviews
Interested in splashing the cash? Or perhaps you'll just settle for being interested at this stage... Either way, here are all of our 4K TV reviews (and videos) to date.
They are in chronological order (and dated), and we will of course be keeping this section updated. Click through to read the full reviews on each TV.
Tested at £7000 – 31.03.12
More after the break
A £25,000 beast of a TV, the 84 inch Sony 4K TV and it's ten surrounding speakers produce an incredible combination of picture and sound, along with passive 3D technology, and uber smart functions, this 4K Sony undoubtedly wowed us when we had some hands on time with it in our test rooms.
Full hands on review: Sony KD-84X9005
Tested at £22,500 – 11.12.2012
The LG 4K TV is another giant 84 inch slab of Ultra HD technology – and it should be, at almost £23,000 it costs more than a five year old Porsche Carrera. Thankfully, the good sound, well thought out smart functions, passive 3D functionality, and of course those 4K pictures, did an impressive job of justifying the outlay if you're serious about big-screen 4K.
Read the full LG 84LM960V review
Tested at £6000 – 13.06.2013
This year we've finally seen a 4K TV at a more affordable price, in a more realistic size, on sale in the UK. Granted, the Sony KD-65X9005 is still expensive, but it's a hefty step in the right direction. And the good news is it looks stunning with 4K content. If only there was more of it. It's not entirely without fault but it's undoubtedly fit for a 4K future.
Read the full Sony KD-65X9005 review
Tested at £4500 – 02.12.2013
We've finally seen a Philips 4K TV – and we like it. Pictures are excellent with HD and Ultra HD content, there's good upscaling from standard-def and the Ambilight feature is an added bonus.
As often the case with Philips TVs, this set takes while to get set-up right, and the amount of smart TV functionality is a little dissappointing, but regardless this is one of the best 4K TVs we've seen so far, and one of the cheapest on the market in the UK in 2013.
Read the full Philips 65PFL9708 review
Tested at £5500 – 05.12.2013
This Panasonic 4K TV currently has something of an advantage over rivals: it's the only set that has an HDMI 2.0 connection, which means support for 4K video at 50/60fps, vital for potential future 4K broadcasts.
Thankfully, and more useful for now, is the brilliant picture across the board, no matter what content you throw at it. Realistic colours, good broadcast TV performance and strong UHD images. Another solid 4K Panasonic.
Read the full Panasonic TX-L65WT600 review
Tested at £5500 – 09.12.2013
LG was one of the first manufacturers to jump on the Ultra HD bandwagon, and after launching with an 84in monsterm, we now have some more realistic LG 4K screen sizes (and prices).
In fact, this set is already available on the market for £1000 cheaper than the price at which we reviewed it. And for 4K and 3D especially, the level of picture performance is impressive.
Read the full LG 65LA970W review
Tested at £5500 - 20.01.14
Toshiba was one of the first companies to get involved in 4K TV and this is the company's latest range (ahead of expected 2014 4K TVs from Tosh').
Unfortunately, it's not quite up to the standard. Not least considering the price. 4K content looks great and colours are nicely judged, while decent 3D performance is a bonus, but blacks lack detail and there are gaps in the spec.
It's a hard one to recommend at this price.
Read the full Toshiba 65L9363 review
The Samsung F9000 range of 55in and 65in Ultra HD 4K TVs are now on sale in the UK for £4000 and £6000 respectively.
Offering four times the resolution of standard high definition, the F9000 sets feature a Samsung Quadmatic Picture Engine, Quad Core processing and Precision Black/Micro Dimming LED technology for deeper blacks.
The Samsung UE55F9000 and UE65F9000 also come equipped with Samsung's usual array of smart TV features including voice control.
MORE: Samsung TVs for 2014
4K TV verdict
Ultra HD 4K TV looks set to make its way in to our living rooms in the not too distant future – now if you've got the inclination and cash – and that's something to be very excited about.
We've been hugely impressed with the Ultra HD 4K TVs that we've seen, notably when playing 4K content, which makes it all the more pressing that we start seeing more concrete plans for 4K content in the UK.
What's next? Well, greater choice of 4K TV sizes and prices would be nice. And how about a 4K OLED TV? We live in hope. Let's see what 2014 brings for 4K TV and 4K content...
by Joe Cox