Ultra High Definition, or UHD. It’s every technophile’s dream. But what is it really?
In order to use the Ultra HD label, displays must have an aspect ratio of 16:9 (at least) and one input with a minimum resolution of 3840×2160. This includes what people are calling 4K using 2160p and 8K at 4320p. That’s compared to today’s HD with a maximum resolution of 1920×1080.
You can buy UHD TVs today for £500 and up (maybe even less if you look hard). If you research brands and reviews you’ll see that many say the current lot of TVs offer quite an advantage even playing standard Blu-ray content (thanks to some fancy upscaling of the resolution). But what about real 4k content?
Well, Netflix and Amazon both offer a 4k streaming service on UHD TVs that include their apps. Not every title is available in 4k though. But a bigger issue is whether or not you can actually see a 4k stream even if you have the TV and the app.
At the Streaming Media West conference, Jan Ozer, an encoding expert, gave a presentation on the subject. He detailed experiments he’s performed on Google’s V9 versus HEVC (which would be used for 4k) and pointed out some of the downsides of HEVC and 4k content in the current landscape. But his conclusion that it will be years before 4k HEVC streaming “is a reality” is somewhat controversial.
I say somewhat because the hard facts support his conclusions, but the arguments against it also hold some validity. For example, Ozer points out that Netflix can only sustain about 3 Mbps over its network, even with all the agreements and peering it uses (you can see the numbers for yourself here: http://ispspeedindex.netflix.com/uk). According to Ozer, Netflix is encoding UHD 4k at 15Mbps, but they can only deliver 3Mbps. So therefore even people with the TVs and the apps really can’t get their 4k streaming – unless they have their own high speed connections.
That all makes sense – you really can’t stream 4k UHD video with current infrastructure. But others have commented that when 1080p HD streaming with H.264 began, less people had the bandwidth for streaming than they would for 4k HEVC today. That’s to say even though it’s a reach, it’s less of a reach than when HD first became available.
So who’s right? Well, as I’m fond of saying in my blog, only time will tell. But with technology, the only certainty is that the future is uncertain. What do you think?