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, Amazon Prime Video and Rakuten 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 has shown a full series of Blue Planet II in 4K, and carried out a couple of live 4K trials through the BBC 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 Xbox One X - premium and budget Ultra HD Blu-ray players are no longer a pipe dream.
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 Formula 1 and boxing, as well as films, dramas, natural history programmes and documentaries in 4K. Could we 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 costs £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 only had 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 over 120 pieces of 4K content available on Netflix at the time of writing, including TV series, documentaries, movies and stand-up comedy specials. 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.
You'll find the necessary Amazon app pre-installed on all the latest models from most of the major manufacturers. If you have an older set, you might need to perform a software update.
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 Jumanji: Welcome to the Jungle, Paddington 2, Blade Runner 2049 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 in late 2017, it’s now finally progressed to show an entire series - Blue Planet II - in Ultra HD 4K and HLG (Hyrbid Log Gamma).
When the final episode aired on 10th December 2017, the BBC made all seven episodes of the David Attenborough-narrated nature documentary available to watch in full 4K and HLG for 30 days on iPlayer.
The BBC has also carried out is first ever live 4K trials on iPlayer. In April, it broadcast an entire rugby league Challenge Cup match and in may it streamed the second half of the FA Cup Final between Manchester United and Chelsea. Whether we'll get to see any matches from the upcoming World Cup streamed in 4K remains to be seen.
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 downscaled 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.
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 around 70 films available to buy or rent on iTunes at the time of writing, 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 charges 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.
Rakuten is another service that offers Ultra HD 4K content for streaming. However, according to the Rakuten website, it's only compatible with 4K Samsung smart TVs running a Tizen operating system (2015 models and newer, and models higher than JS6000) and 4K LG smart TVs with WebOS (2016 models and newer). The company recommends a minimum internet connection of 20Mbps.
Rakuten recently announced a partnership between itself, LG and Dolby to bring Dolby Vision (and Atmos) movies to its film rental service. It also announced that it will upgrade already-purchased Full HD films to 4K HDR for free, where available.
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, test cricket and some boxing matches.
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.
Eurosport is launching a 4K Ultra HD channel especially for its coverage of the 2018 French Open from Roland Garros. Eurosport 4K launches on Sunday 27th May and you'll need either a Sky Q 2TB or Virgin TV V6 set-top box and a relevant subscription package to view it.
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.
Given the BBC's recent live trials, it's more likely we'll see games streamed over the internet through their respective BBC iPlayer or ITV Hub apps.
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 well over a hundred titles (new and old) being released in 4K.
Discs that can handle resolutions up to 3840 x 2160 and up to 60fps (frames per second) are 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 using the High Efficiency Video Coding (HEVC) standard, and includes 10-bit colour depth and the Rec. 2020 colour space.
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, Sony XZ2 Premium and the Samsung Galaxy S9+, 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.