The next evolutionary development in display technology is almost upon us. Perhaps surprisingly, this innovation comes not from computers, but from the film and television industry.
Emerging From The Past
For most of their existence computer monitors have been tied with television standards. In the beginning, they were one and the same: early personal computers used domestic televisions to display their graphics and text. Computers quickly leapt over these early limitations, with television catching up again when HDTV became standard. Since then, high-end computer displays have far surpassed HD: a Retina MacBook Pro laptop display clocks in at 2880 × 1800 pixels.
Now it is time for television to leapfrog again. 4K TV sets have been available in stores for some time, and prices are plummeting: dipping down to $400 as I write this; Dell's new 24″ Ultra HD monitor is not too far behind.
Diving Into Oceans of Pixels
So what does 4K offer? A minimum display of 3840 by 2160 pixels: four times the resolution of HDTV. This is the same standard used in digital cinema: if your local theatre uses digital projection, that’s the resolution you’re seeing on the movie screen.
You’ll note that the horizontal pixel count isn’t quite 4000 pixels across, which is a source of confusion. The television standard – known as ultra high definition television, Ultra HD, UHDTV or UHD – is 3840 by 2160 pixels. True 4K resolution, associated with computers, is 4096x2160, adding an extra 256 horizontal pixels. It’s a small difference, but an important one: to display UHD broadcasts, true 4K monitors will either have to slightly stretch the image to fit the screen, or add vertical letterboxing outside the frame. As I am approaching from the perspective of computer displays, I’ll use “4K” to describe the technology as a whole, and UHD when referring to television.
What does this ocean of pixels provide? A richer, more detailed, vibrant display, more room, and a greater immersive experience. Future UHD standards may also include higher frame rates and a wider color gamut.
A Dearth Of Native Content, At Least For Now
Currently, there is little native 4K content available: Japan and Europe receive limited UHD satellite broadcasts, but the majority of 4K content can be found online: YouTube and Vimeo support 4K videos, and Netflix has started to stream UHD programming. Outside of these limited areas, consumer-level UHD content doesn’t exist: Ultra High Definition Blu-Ray players and discs won’t arrive for several years, with television broadcasts likely catching up after that*. There is plenty of content waiting for 4K: most digital Hollywood productions are filmed at least that resolution, and are simply awaiting the consumer infrastructure.
The “wow” factor of current UHD sets is almost entirely due to retail stores streaming 4K recordings from a hard drive, or upscaling a 1080p source to four times its native resolution. As I’ve discussed in the past, this latter approach makes images bigger but not necessarily better: while impressive, you can expect significantly improved visual quality from a native UHD source.
Another potential limiting factor is throughput: most existing cabling and transmission standards simply aren’t up to carrying UHD signals without significant compression, which degrades image quality. Thunderbolt 2 and DisplayPort 1.2 have enough capacity, but ideally you’d want any display you purchase for home entertainment to also have HDMI 2 connections.
Tied into this is the refresh speed of UHD panels themselves: 30Hz is okay for movies, but can leave a visible trail from rapid mouse movement; the ideal display would boast 60Hz at full resolution. Associated with this is the ability to drive millions of pixels at a decent frame rate: video cards and GPUs are obviously an important consideration for computers.
The UHD standard provides consumer electronics manufacturers with the opportunity to make screens larger – big living room displays that will not look like they are punching your face with grossly magnified pixels – or smaller, crushing UHD down into handheld “Ultra Retina” devices. Expect to see both in the near future. Of course, this is nowhere near the event horizon of resolution: WHXGA (5120 × 3200 pixels, in a 16:10 aspect ratio) should arrive soon for computer monitors, and consumer 8K standards, equivalent to the resolution of an IMAX screen, are already being worked on.
Web Developers & 4K
A number of developers have made the leap to 4K as a desktop environment: 39″ screens can present a lot of information at one desk. Of more immediate concern is how 4K will affect web pages for users in the near feature:
- Responsive design becomes more important than ever. You should already be designing your web pages to take advantage of 27″ displays. A significant number of UHD televisions will be “smart”, carrying their own, built-in browser. Start considering what happens to your sites when the browser window is 4000 pixels across.
- Fight the bloat. The average web page is already at 2MB in size. Quadrupling image resolution – increasing page size to 8MB - is not going to be a solution. We have to think smarter.
- Use SVG as much as possible. Vector graphics are immune to resolution changes, making them perfect for 4K and higher displays.
- An adaptive image standard is an imperative. We can’t feed 4K bitmap images to every device; using
<picture>is a neccessity.
4K offers a fresh set of challenges to the web developer, but they are not insurmountable: with consideration and planning, we can have web pages displayed at an equal quality on 104″ and 4″ screens.
* Broadcasters will be reluctant to reserve the bandwidth required for a single UHD signal, knowing they could use the same space for 4 HD channels.
** More about these in future articles.
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