One of the questions that’s come out of Microsoft’s Xbox One reveal last week is to what degree the console actually supports 4K content. When asked about 4K support, Microsoft’s Corporate Vice President of Marketing, Strategy and Interactive Entertainment Business Yusuf Mehdi told Forbes that: “The video and interface portions, absolutely. Games developed for 1080p will run at 1080p, obviously.” It will support up to 4K at launch for things like Blu-ray, but what about later? “There’s no hardware restriction there at all.”
The accuracy of that statement depends entirely on which hardware Mehdi was referring to. The Xbox One’s CPU and GPU are definitely powerful enough to handle 4K decode or 3D video display, but that’s only one link in the content chain. There are several current barriers which make 4K a dubious proposition on the Xbox One come launch day. We’ve highlighted whether these issues apply to the Xbox One, PlayStation 4, or both systems below.
Blu-ray compatibility (Xbox One and PS4): At the time of the writing of this article, there is no defined Blu-ray standard for content above 1080p and no decision is expected until the end of the year. That leaves Sony and Microsoft stuck with guessing. The simplest way for both companies to hedge their bets is to include BDXL drives in their consoles rather than standard BD-ROMs. BDXL drives can support up to 128GB discs; the current mass market standard is 50GB.
Sony’s “Remastered in 4K” films are 1080p films that have been converted from 4K originals. The company is also putting all extras and bonus content on separate discs in order to maximise the amount of video bandwidth available for the feature film. It’s clear that Blu-ray needs an upgrade to keep pace with content standards – Peter Jackson’s The Hobbit was only released in 24 fps because there’s not enough room on a BD disc for the film and no formal definition for a 48 fps playback format.
No codec standard (Xbox One and PS4): 4K content could presumably use either H.264 or H.265 for encoding. H.264 is more compatible and already supported by the Blu-ray standard, which would make backwards compatibility easier to achieve, but it takes up twice as much storage space as the newer H.265. H.265 is a more efficient codec than H.264, but requires more CPU power for decoding. The PS4 and Xbox One will both use an AMD-based video decode engine for offloading this work, but it probably won’t support H.265; the standard is simply too new.
HDMI 1.4 output (Xbox One and PS4): HDMI 1.4 is the latest released version of the HDMI standard (version 2.0 won’t be released until later this year). HDMI 1.4 supports 3840 x 2160 output at 24p (24 fps, progressive) or 30p. That may not seem like much of a problem, but it means the Xbox One couldn’t display a hypothetical version of The Hobbit running at 48p on a new Blu-ray standard. 4K 3D, if it ever takes off, would also require HDMI 2.0.
As it stands, Sony hasn’t said anything about its own supported outputs – but there’s nothing to suggest Sony has a trick up its sleeve on this one; HDMI 2.0 isn’t ready for market. This issue will almost certainly affect both consoles.
Stream size (Xbox One and PS4): The last barrier to native 4K content has nothing to do with Microsoft or Sony. A 4K video contains four times as much data as a 1080p video. Even if you use H.265 for streaming, you’ll end up with a stream twice the size. This is going to naturally slow the rate of 4K video adoption.
H.265 will shift this requirement substantially lower. Keep in mind, this graph shows 30 fps speeds – if you want to stream at higher rates, the bitrate increases in any platform.
Forging the chain
The reason there’s so much uncertainty around 4K video is because the standards necessary to achieve it are actually less developed now than the HDTV standards were when the Xbox 360 and PS3 launched. Both consoles will be capable of outputting their own interfaces at 4K. Both are apparently designed to upscale 1080p video to 4K, though we expect 4K TVs to have their own upscale solutions as well. Both consoles should be able to handle decoding native 4K content in both H.264 and H.265, though the H.265 solution may be implemented in software.
We will be surprised if the launch versions of the Xbox One and PS4 offer flawless support for a native 4K version of Blu-ray. Capabilities like 4K 3D will not be supported, due to limitations in the HDMI 1.4 standard. Local 4K file playback on the Xbox One may be hampered by the unit’s relatively small hard drive, though it’s not clear how easy it will be to move hypothetical 4K content from PC to Xbox in any case.
The bottom line is this: Don’t expect perfect 4K compatibility out of the gate from either console. The standard is too young, and support is too scattered. If you love being on the cutting edge, and you’re planning to buy into 4K television and wondering when 3D content will be available in native formats, the answer is: “A while.”
So what about 4K gaming?
Sony has been straightforward on this point – no 4K gaming. Microsoft is being cagier, with comments like: “Games made for 1080p can work at 1080p.” The most likely explanation for Microsoft’s evasiveness is that the company doesn’t want to take 4K gaming completely off the table, but has no plans to target it for mass market games. Without diving into the particulars of GPU design, the bottom line is this: A 4K resolution would require far too much memory to maintain the Xbox One’s stated 60 fps target. Hitting 30 fps would likely be a struggle for games with any kind of detail.
Thus, it’s likely that the Xbox One will “support” 4K gaming in much the same way that Sony is likely to do so – via hardware upscaling. Whether that upscaling will be handled by the GPU or offloaded to the television is unclear, but native 4K resolutions aren’t going to happen this time round in any sort of comprehensive fashion. The fact that Sony has taken 4K gaming off the table altogether tells you all you need to know – in this case, brute force matters, and the PS4 would be the platform to take a shot on the resolution if it made sense to do so.
The final caveat
After all the discussion of 4K, there’s one last thing to remember. The benefits of 4K, unless you plan to upgrade to an enormous television, are going to be virtually invisible. Unless you sit extremely close to the screen, or have better than 20/20 vision, you’re never going to see a benefit from 4K.
At a viewing distance of eight feet (2.4m), you need a 65in television to see the 4K/1080p difference. That makes the benefit of the upgrade dubious for most, and likely a low priority for Sony and Microsoft given the other technological barriers to adoption.