From our experience, 4K Ultra HD has always looked incredible, delivering impressive detail and clarity. But when it comes to 4K video content, for a long time we struggled to find much more than promotional videos of flowers and cityscapes. Thankfully, that's finally started to change...
Video-on-demand streaming services such as YouTube, Netflix and Amazon Prime Video all offer 4K films and TV shows - some free, some paid-for. Apple is now offering 4K downloads on iTunes at fairly affordable prices, while the BBC only recently showed a full series of Blue Planet II in 4K on iPlayer.
But the biggest news, especially if you want the very best picture quality, is that Ultra HD Blu-ray discs and players are here.
From dedicated 4K disc-spinners such as the Panasonic DMP-UB900, Oppo UDP-203 and Sony UBP-X800, to games consoles such as Microsoft's Xbox One S and the latest Xbox One X - Ultra HD Blu-ray players are no longer a pipe dream (and they're getting more affordable, too).
We're also seeing more Ultra HD Blu-ray discs going on sale in the UK - now numbering in the hundreds and spanning new and old titles.
As for 4K broadcasts, the BT Sport Ultra HD channel and Sky Q are among the first to offer live 4K coverage of sports such as Premier League football, cricket and the 2017 Formula One season, as well as films, dramas, natural history programmes and documentaries in 4K. And we might even get the 2018 World Cup in 4K HDR.
Allow us to round up in full the different ways you can watch 4K content right now...
How to watch 4K on Netflix
Netflix was one of the first video-on-demand services to announce it would be supporting 4K streaming, and in April 2014 it went live in the UK. But to access the content, you need to have the right kit.
To watch Netflix 4K online, your 4K TV will need to support the HEVC (High Efficiency Video Coding)/H.265 compression standard. The first generation of 4K TVs didn't support this - they instead came with the H.264 codec, which doesn't support most of the 4K content now available.
You'll also need to make sure your 4K TV (or other necessary kit) has an HDMI 2.0 connection that is HDCP 2.2 compliant. This ensures copy protection compliance for 4K content coming from an external source.
If you have a non-compatible 4K TV, all is not lost. Manufacturers can release software updates - Panasonic, for example, has released a software update for its AX802 series (you can read the What Hi-Fi? review of the 58in version), which enables it to stream Netflix in 4K.
The simplest way to see if your set is compatible is to check it against this full list of Netflix 4K compatible TVs.
You will also need to sign up to Netflix's 4K Ultra HD plan, which has recently risen in price to £10 per month. This subscription plan comes with the added benefit of users being able to watch content on up to four screens at any one time, all from one account.
And finally, you need a solid internet connection. Netflix recommends a speed of at least 25Mbps, but ideally higher, for streaming 4K video.
Once you've ticked all those boxes, you're ready to start watching. But what content is out there? It's still relatively low on 4K movies but high(er) on 4K TV shows.
At first Netflix had only a few TV shows and some scenic footage to show in 4K, but the amount of content on offer has grown to over 50 TV series, including The Crown, Stranger Things, House of Cards, Breaking Bad, 13 Reasons Why and Marvel's Daredevil.
There are also 25 documentaries, 21 movies and 16 stand-up comedy specials available at the time of writing. You can find a full list of live 4K content on Netflix here.
How to watch 4K on Amazon
Amazon is also offering 4K content through its Prime Video streaming service. For those with Prime memberships, a range of Amazon Original TV shows are available at no extra cost.
You can watch 4K video through the Amazon Prime Video app on compatible TVs and the latest 4K Fire TV box and Fire TV 4K (2017) stick. You can see a full list of Amazon Prime Video devices here - note this is a list of devices that are compatible with the movie streaming app as a whole, not necessarily 4K content.
The Amazon 4K service was initially available only on Sony 4K TVs, but the latest models from most of the major manufacturers now come with the app pre-installed. If you have an older set, you may need to perform a software update.
Microsoft recently updated the Amazon Prime app for its Xbox One S games console, so it now supports streamed 4K HDR content.
Amazon's service offers a good selection of 4K films and TV shows. You'll find TV shows, including Amazon Originals such as American Gods, The Man in the High Castle, The Grand Tour, Transparent and Red Oaks, all available in 4K and all included in the Prime price. Mozart in the Jungle, The Grand Tour and Red Oaks are also available to stream with High Dynamic Range (HDR).
Films available to stream include The Amazing Spider-Man 2, Moneyball, The Da Vinci Code and more - all on a pay-as-you-go basis. Rental prices start at £1, though £7 is more standard (and not all films can be rented). To buy, you're looking at between £5 and £14.
How to watch 4K on BBC iPlayer
BBC has been promising 4K content on its on-demand streaming platform for nearly two years now, and after showing a snippet of Planet Earth II in 4K late last year, it’s now finally progressed to show an entire series - Blue Planet II - in Ultra HD 4K and HLG (Hyrbid Log Gamma).
Ever since the final episode aired on 10th December, the BBC has made all seven episodes of the David Attenborough-narrated nature documentary available to watch in full 4K and HLG for 30 days on iPlayer.
It expires on 16th January (after which the 4K Blu-ray can be bought) so we'd urge you to start watching before it's gone. We have, and can confirm it looks spectacular.
So what do you need to watch Blue Planet II in all its 4K glory on iPlayer? For starters, you will need a broadband connection with a speed of at least 23mbps (although those with a standard ADSL will still supposedly get “better quality” than the normal iPlayer offering).
You’ll also need a compatible 4K HDR TV, with the good news being the list of supported TVs is fairly long and includes 2015, 2016 and 2017 models of popular brands. You can see a full list of compatible devices here. The Sky Q platform is also compatible.
Then simply hit the "UHD" option on your TV's iPlayer app, and away you go.
How to watch 4K on YouTube
YouTube has been supporting 4K Ultra HD video since 2010, but, as with the two previous services, there are requirements.
YouTube Ultra HD videos don't use H.265 compression. Instead, they use the VP9 codec, which is royalty-free, meaning its adoption rate could potentially be higher. It is also said to be more efficient when it comes to streaming Ultra HD video.
So how do you watch 4K YouTube videos online? Google implemented the VP9 codec into its Chrome browser and YouTube in 2013, so both have been able to support 4K streams for some time. If you search 4K content within YouTube right now, you'll be able to select 4K as a quality option on each video.
But, as with HEVC/H.265, VP9 needs compatible hardware (ie. a 4K screen) to watch it on. Most new PCs should support the VP9 codec, but it's something to keep an eye out for.
If you don't have a compatible display, the video will be downsampled to the maximum output of your monitor.
More after the break
How to watch 4K on Apple iTunes
Apple has – rather belatedly – joined in on the 4K fun, finally launching its first 4K- and HDR-supporting Apple TV 4K box. Plug it into your 4K TV,and it will give you access to a wide range of 4K content via Netflix, YouTube and Amazon Prime Video (the latter coming soon via an imminent software update).
But what makes Apple’s proposition unique is access to its iTunes library – which now includes a wealth of titles in 4K and HDR (and Dolby Vision too). There are currently around 70 films available to buy or rent on iTunes, including recent blockbusters such as Wonder Woman, Alien Covenant, Logan and Baby Driver, which are otherwise only available on 4K Blu-ray.
What's more, Apple has said it will charge the same price for 4K films as it does for HD films (typically £13.99, sometimes as low as £9.99), which is a huge step forward for fans of 4K. It's in sharp contrast to the price of 4K Blu-ray discs (usually over £20) and the premium charged for 4K Netflix, too.
And if you’ve already bought a film from iTunes that’s now available on the store in 4K? You automatically get the new version at no extra cost. All of which is good news for those who want more 4K content.
You will need to sign up for an iTunes account (which is free) and get the new Apple TV 4K box (which isn’t cheap at £200), but it’s a decent start if you want one of the best and most affordable 4K HDR movie streaming libraries currently available in the UK.
Where else can you stream 4K video?
UltraFlix is a 4K streaming network from NanoTech, and has apps on Samsung, Sony, Vizio, Sharp and Hisense TVs. The 4K UltraFlix Network App claims to offer the "world's largest library of 4K VOD content", including "hours of free content" from movies, concerts, documentaries and special events to 40 made-for-IMAX theatrical titles.
We access the app tedhrough a Sony TV, but prices for content are in US dollars. We watched some free content but noticed it buffered quite a bit, even with a suitable Internet connection.
What about watching 4K TV broadcasts?
BT became the first broadcaster to bring an Ultra HD channel to the UK, with the launch of BT Sport Ultra HD. The channel launched in August 2015 and promised to show one live Ultra HD event per week.
The focus is primarily on football, but it has also shown other events including the MotoGP, NBA basketball and Aviva Premiership rugby.
The channel is supported by the majority of 4K TVs released from 2014/15 onwards, but you will need to subscribe to the Ultra HD package, have an Infinity Fibre broadband connection and get the new BT Ultra HD box fitted.
Sky claimed it would offer the "UK's most comprehensive Ultra High Definition service" through its Sky Q platform in summer 2016, and it certainly stuck to that promise. Sky Q Ultra HD launched in August 2016, with a wide range of content available at no extra cost to Sky Q subscribers (provided you subscribe to the relevant TV package).
While football again features heavily, there are also movies and TV shows, F1 and Test cricket.
You'll need a Sky Q 2TB box (known as the Sky Q Silver box when it launched), as well as a subscription to Sky Q Multiscreen.
While it is a huge step forward for 4K broadcasts, Sky's content won't come with the added benefit of High Dynamic Range (HDR). "HDR as a standard hasn't settled down yet," says Sky's director of TV experience David Cameron. "When it does, we'll look at moving forward."
The Sky Q 2TB box also upscales standard and high definition content to 2160p, 4K resolution.
MORE: Sky Ultra HD review
What about 4K on terrestrial TV? The BBC filmed Planet Earth II in 4K, released a four-minute 4K clip via iPlayer and followed it up by making the entirety of Blue Planet II available to stream - but it's still keeping quiet on when it'll actually broadcast in 4K resolution. At the moment, it looks set to continue with its "internet first" approach.
But there's potentially good news on the horizon: FIFA has announced that the entire 2018 World Cup will be filmed in Ultra HD 4K and HDR - but those of us in the UK need the BBC or ITV to launch a 4K channel in time for kick-off on 14th June 2018. No pressure.
Not so long ago,mind you, the BBC claimed it would aim to broadcast 4K as standard by 2016 - and look how that turned out. We can only hope 2018 is the year 4K terrestrial broadcasts become a reality.
What about 4K on PlayStation or Xbox?
Sony has its own 4K Video On Demand service which is part of the company's PlayStation Video service.
The service includes 4K content, but only in the US. To access 4K content, you need one of Sony's 4K Media Players, such as the FMP-X1, or one of the selected US Sony 4K TVs. Films range from $8 for a 24-hour rental to $30 to buy. Sony says it has "no plans" to bring the 4K Media Player to the UK.
Sony's PS4 Pro is equipped for playing 4K games, but it doesn't have an Ultra HD Blu-ray drive. Sony has also launched an Ultra app, which brings 4K videos to selected Sony Android 4K TVs. Again, it's only available in the US for now.
Xbox One X boasts similar 4K functionality to the One S in a more powerful package. It can also render 4K games natively. During testing we felt the 4K Blu-ray performance of the One X was superior to its sibling.
How to watch 4K Blu-ray
For many, getting a broadband connection that's fast enough to support 4K streaming (realistically 15Mbps at the very least) isn't possible right now. Therefore a better way to get 4K content into the home would be on a disc format.
The good news is Ultra HD Blu-ray is here. After a slow start, there are over a hundred titles (new and old) being widely released in 4K.
Discs that can handle resolutions up to 3840 x 2160 and up to 60fps (frames per second) can be classed as Ultra HD, and the format also supports high dynamic range (HDR), higher frame rates (up to 60fps) and object-based immersive sound such as Dolby Atmos and DTS:X.
HDR on 4K Blu-ray discs appears in two varieties: HDR10 and Dolby Vision. Video is encoded under the High Efficiency Video Coding (HEVC) standard, and uses 10-bit colour depth and the Rec. 2020 colour space.
You will, of course, need a new Ultra HD Blu-ray player to play the discs. We've tested more than a few, including five-star standouts the Sony UBP-X800, Oppo UDP-203 and Panasonic DMP-UB900. And there are more on the horizon, such as Cambridge's CXUHD and a higher-spec Oppo UDP-205.
Not convinced that UHD Blu-rays are the future? There's a strong argument that they're superior to 4K streaming...
Make your own 4K video
Still not satisfied? You could always create your own 4K Ultra HD content.
An increasing number of phones are now able to record 4K video, including (but not restricted to) the Apple iPhone 8 Plus, iPhone 7 and 7 Plus and Samsung's Galaxy S8+, meaning you can make your own 4K movies in no time. And of course there are also plenty of 4K cameras available.
It's one easy and cost-effective way to fill the 4K gap. Though we're guessing your masterpieces may not match the quality of Blade Runner 4K or House of Cards...
The 4K verdict
The growth of 4K content means the format is becoming an increasingly tempting proposition.
The amount of content available to stream is rising all the time and, while it relies on a high-speed internet connection, it offers the most extensive catalogue.
4K Blu-ray discs are here too, and from what we've seen they offer superior audio and video performance to streaming. As expected, the trickle of available titles is fast becoming a flood - they're borderline mainstream options now.
As for 4K TV broadcasts, things are starting to move in the right direction. Now that Sky and BT are broadcasting in the format, interest is bound to catch on. The main obstacle is the cost. 4K TVs are becoming more affordable, but Sky and BT's services aren't cheap. We're looking at you, BBC, to make that final leap...
On the bright side, it's now more viable than ever to put a 4K TV in your home. And there's finally something - in fact, a lot of things - to watch on it.