A 4K video primer

Samsung SUHD-9500_16x9

4K. Four Kay. Ultra High Definition. UHD. Forky. Puuuurdy. No matter what you call it, the replacement for 1080p HD resolution is now a standard part of the home entertainment lexicon.

Like the megapixel race of the cameras of yore, and the MHz race of CPUs of even more yore, there’s been a push for higher resolution screens. And indeed, with larger TVs becoming standard, and projectors moving from ‘enthusiast’ to ‘consumer’ levels, there’s a definite need for more pixels.

So, how many pixels are there in 4K, compared to 1080p HD? To start, the term ‘4K’ isn’t quite as clear cut as it should be: in the cinema world, 4K has been around for years, and has meant anywhere between 4,096 x 1,744 and 4,096 x 3,072 pixels (used across about 10 standard aspect ratios and sizes), whereas the consumer tech now referred to as ‘4K’ or ‘UHD’ is generally 3,840 x 2,160 pixels.

8K_UHD,_4K_SHD,_FHD_and_SD.svgWhy the difference? Well, 3,840 x 2,160 simply doubles the horizontal and vertical resolutions of the existing 1080p standard, resulting in four times more total pixels and allowing it to retain the 16:9 widescreen aspect ratio that digital TV is broadcast in and that all our TV sets conform to. In other words, it makes sense to stick with it.

While more is usually regarded as better, does it make sense to increase the number of on-screen pixels? As we’ve previously alluded to, on many screens and from most seating positions, your eyes aren’t actually able to tell the difference between regular ol’ 1080p HD and 4K. Where 4K does shine, however, is on the new, larger HDR screens.

Why should I go 4K?

Image Credit: Carlton Bale, s3.carltonbale.com/resolution_chart.html

Image Credit: Carlton Bale, s3.carltonbale.com/resolution_chart.html

How large, you ask? Well, in order for you to discern the edges of those 8.2 million or so pixels, you’ll have to be sitting within 1.5m of a screen about 60-inch in size (the larger the screen, the further back you’ll be able to notice pixels). On screens smaller than 55-inch, there’s almost no point, unless you’re sitting within a metre — like at a desk.

For these reasons (and because 55-inch TVs make up 64% of all TV sales, according to LG), it seems unlikely that 4K TVs smaller than 55-inch will arrive on the market in the near future — even though 4K PC monitors are selling like pulled pork brioche burgers at hipster bars.

However, even if you don’t buy into the arguments put forth for extra pixels, 4K videos — depending on their source — will bring a host of improvements in addition to their increased resolution.
First, though, let’s discuss those sources, as getting your digital mittens on 4K video is actually a bit trickier than you might expect.

4K sources

Netflix_PR_UI_PRINT_RegDarwin_OutofDevice_AUSPerhaps surprisingly, despite there being a multitude of 4K TVs on the market, there is but a handful of external 4K playback sources and only a sliver of 4K content.

Netflix and YouTube are the two biggest 4K streaming services at the moment, and while many 4K TVs out there will support Netflix natively via a wired Ethernet connection, there is only a limited number of ‘UHD’ (Netflix’s preferred term) movies and TV shows available from the service.

At the moment, there’s no way to get 4K Netflix streams playing on your PC — the browser UI just doesn’t support it. Hopefully this is something that Netflix will amend in future. Conversely, while there are a lot of people uploading 4K (cat) videos to YouTube, it’s still only possible to access these from a PC.

Additionally, you’ll need a hefty internet connection and download quota to be able to really take advantage of streaming 4K.

Netflix’s ‘UHD’ stream clocks in at 15.5 megabits per second (Mbps) or 1.9375 megabytes per second (aka MB/s — note the capital ‘B’). With the average connection speed in Australia at around 7.4Mbps (according to Akamai’s Q4 2014 State of the Internet report) and only 16% of households on a connection above 10Mbps.

Netflix actually recommends an internet connection of greater than 25Mbps (3.125MB/s) for UHD, which eliminates ADSL2+ completely [insert political comment about the near-sightedness of the current incarnation of the NBN], which tops out at a maximum (and almost never achieved) 24Mbps or around 3MB/s.

As such, if you’re considering streaming 4K, we’d recommend popping over to speedtest.net and seeing how your connection rates, as if you’re dead set on the idea you may need to switch to a more expensive cable or fibre link (if available, of course).

Just be sure that you have a generous download limit, too, as you’ll find a two-hour UHD movie from Netflix sits close to 18GB in size, and a 13-episode TV series at a staggering 117GB.

Notably, at the time of writing, no other Australian streaming services, such as Stan or Presto, support 4K. There are several services in the US that do, though, including Amazon, so if you have an unlimited quota VPN, that’s definitely worth looking into (and, incidentally, by connecting to the US version of Netflix, you’ll also get access to more 4K content than is offered on the Australian Netflix).

Crucially, if you’re looking to stream Netflix to your 4K TV, check that it is indeed certified for it. It not only has to support the new HEVC codec, but Netflix itself has to certify devices for playback, too. (Some 4K TVs may only need a firmware upgrade to get that certification, thankfully.)

If your TV isn’t out-of-the-box Netflix UHD compatible, you can consider hooking up a HTPC (home theatre PC) to your TV, and setting up a proper geek’s lounge room. See our PC builder’s feature on page 52 for full details, but at the minimum — that offers DisplayPort output, and preferably HDMI 2.0, as otherwise you may be limited to a 30Hz refresh rate.

When it comes to 4K, the main benefit of an HTPC is that you can watch other 4K content, such as YouTube or anything you download yourself.

Playback of 4K content via USB storage is now a standard feature for 4K TVs, but wasn’t the case in 2013 when the first models came out. Some of the cheaper 4K TVs may also have problems playing-back downloaded 4K content over USB, so make sure to check before you commit.

MINIX-NEO X8-H Plus_02Another option for viewing 4K content on your TV is to purchase one of the many Android-based, 4K-compatible mini PCs now on the market (such as the Minix Neo X8-H Plus, which is just over $200 on eBay). While these can play back 4K movies, they’re not certified for Netflix at anything above 1080p. (We haven’t had the luxury of trying one out, so can’t speak of their quality. Minix have been around for a few years, though, and seem to have a strong following.)

Unfortunately, games-console owners are basically out of luck when it comes to 4K: the Xbox One doesn’t support it at all, and the PlayStation 4 only supports it at 30fps (thanks to its HDMI 1.4 port), and even then, the PS4’s Netflix app only supports up to HD resolution, and the PS4 doesn’t allow you to bring your own 4K videos and the PlayStation Video service only supports 1080p streaming.

However, rumours abound that both the Xbox One and the PlayStation 4 will receive hardware updates this year that will upgrade them to HDMI 2.0 and enable 4K playback at 60fps from streaming sources like Netflix, and maybe even locally-stored content, too. They may even support the soon-to-be-released 4K Ultra HD Blu-ray discs.

4K Blu-ray – more than just pixels

4K Blu-ray discs should be coming out before the end of 2015 (there were some prototype 4K Blu-ray players seen at CES earlier this year, so they’re getting closer). The discs will be encoded using the newer HEVC/H.265 codec, which is a much more efficient method of compression (in fact, HEVC stands for High Efficiency Video Coding).

In tandem with this improved compression will be an increase in the capacity of Blu-ray discs — up from 25GB or 50GB to 66GB and even 100GB. Most notably — and this is where the superiority of physical media over streaming plays out — all that extra space will allow for more than just extra pixels: each pixel will also be filled with more data! So, movies coming on the new discs will also support a wider colour gamut, better contrast, and faster frame rates.

CIExy1931_Rec_2020_and_Rec_709.svgMovies stored on 4K Blu-ray will use what is called the BT.2020 (aka Rec. 2020 or ITU-R Recommendation BT.2020) standard for video, which defines a video format’s resolution (either ‘4K’ 3,840 x 2,160 or ‘8K’ 7,680 x 4,320 — although it will be a while before we see anything 8K), its possible frame rates (from 24 up to 120 — useful for 3D — with many stops in-between), and the bit-depth of the data (either 10 or 12 bits per sample — up from the 8 bits seen today, which translates to a jump from 16.78 million colours to 1,073,741,824 colours for 10-bit and a whopping, staggering, jaw-dropping 68,719,476,736 colours for 12-bit).

Now, the BT.2020 recommendation is built for the future, so 4K Blu-ray will sit at the bottom of the specs — that is 4K resolution, 24fps (for most content, but up to 60fps for some), and 10 bits per sample — but this is still a fundamental shift in picture quality. So much so that current TVs can’t even display all those new colours and shades (and that includes many current 4K sets), and will likely have to sample-down when faced with them. That is, unless you have an ‘HDR’ TV.

The future is HDR video

Sony-VPLVW1000ES-Projector‘HDR video’ (or High Dynamic Range) has been an industry buzzword for a bit, but really made itself known at this year’s CES, where there were sample TVs on display from LG, Sony, Samsung, Philips, Panasonic and others, and Dolby announced its standard for HDR, known as ‘Dolby Vision’.

The ‘dynamic range’ that HDR refers to is basically the difference between the darkest object and the brightest object that can exist in a frame together — in this sense it’s almost another term for ‘contrast ratio.’

However, it also encompasses the possible shades of colours, too. And, as contrast ratio plays a bigger part in the perceived quality of an image than resolution, you can see why we’re a little excited about HDR screens and HDR movies (whether via a lightly compressed 4K Blu-ray or heavily compressed Netflix stream) coming to our home theatres.

Basically, with an HDR movie playing on an HDR screen, expect significantly more realistic pictures — not only will you have deeper blacks alongside brighter whites, you’ll also have many, many more shades and colours in between.

It’s actually quite a technical achievement to have so many colours and shades displayed on a panel, and has only become possible recently thanks to ‘quantum dot’ coloured backlighting technology for LCDs as well as the maturation of OLED panels.

Sadly, however, as at the time of writing, there’s been no mention of a firm release date for 4K Blu-ray (or whatever it may ultimately be called), but rumours are pegging it as ‘late 2015.’ Like every other launch of a new medium, expect both the players and the releases to be very thin on the ground at launch.

However, unlike when Blu-Ray launched back in 2006, there isn’t a competing physical format, like HD DVD or Betamax (just video on-demand streaming services) — all studios are on-board to support it as the medium of choice for 4K content, which is a boon for consumers.

The biggest challenge for 4K Blu-ray, however, is the very simple fact that sales of physical media are down. And as shiny and technically impressive as the format is, Joe Consumer won’t care a hoot about it if he can get the ‘same thing’ streaming over Netflix. So, watch this space for updates.

  • Playback of 4K content by way of USB storage is now a standard function for 4K TVs, but wasn’t the case in 2013 when
    the very first models came out. A number of the cheaper 4K TVs may well also have issues playing-back downloaded 4K content material more than USB, so make certain to check before you decide to commit.

  • Kyle Tremel

    Xbox one is 4k compatable. Dunno where ya got that info just ask microsoft just like I did and 4k blu rays have been out for months. “Early 2015” you should change it too.