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How Sony’s PlayStation 4 Pro does 4K without delivering 4K

Yesterday, Sony took the wraps off its PlayStation 4 Pro, in what was undoubtedly meant as an exciting launch unveil but came across as rather confused, instead. There’s been a lot of chatter over what the PS4 Pro can and can’t deliver with regards to 4K, so let’s unpack that question.

The GPU inside the PS4 Pro is widely believed to be a downclocked variant of AMD’s RX 480 running at 911MHz. This GPU is substantially more powerful than the PlayStation 4’s GPU, with twice the CUs and a higher clock rate. It’s absolutely capable of delivering much better performance than the PlayStation 4 could. But can it push 4K? That’s a more complicated question than it might seem.

The consumer 4K standard (technically it’s 3840×2160) refers to the number of pixels being drawn on-screen. It’s not an intrinsic image quality metric and it doesn’t say anything about the level of detail in a given title. There are plenty of PC titles from multiple generations that will happily display themselves in 4K (whether their menus, UIs, or other elements will be legible in that mode will depend on the title, but the game itself will render at native 4K). When Sony says the PS4 is capable of 4K output it doesn’t tell us anything about the kinds of games that the PS4 Pro can render in 4K or the detail levels they’ll offer when using that mode.

Naughty Dog, for example, has promised that The Last of Us will run at 4K native resolution on the PS4 Pro. But — and this is critical — the Last of Us is originally a PS3 title, and while Naughty Dog made some substantial improvements and enhancements to the game when it shipped on the PS4, it was still built with a last-gen console in mind. The screenshots above show the difference between the [email protected] version of the game that shipped for PS4 and the 30 FPS, 720p version that debuted on the PS3. Some scenes show significant differences while others are quite similar.The Last of Us for the PS4 Pro will have at least two different flavors: A native 4K version with further graphics enhancements locked to a 30 FPS frame rate and a lower resolution version that will run at a steady 60 FPS.

Naughty Dog may be able to push The Last of Us up to a native 4K resolution thanks to its roots in PS3-era graphics, but what about upcoming titles? Here, Eurogamer thinks they’ve found the answer. One potential technique discussed by Valve’s Alex Vandros involves using a checkerboard pattern to reduce the detail level and save bandwidth in VR.

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I’m not as confident as Eurogamer that the slides above actually refer to the same checkerboard pattern Sony apparently mentions in the PS4 Pro’s documentation. Valve’s Alex Vandros was referring specifically to VR and looking for ways to trim detail in areas the eye isn’t focused on. This works because it exploits how the eye focuses on specific areas of the screen, but the same technique may not be adaptable to a 4K flat panel.

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Upscaling seems simple: It’s the process of taking an image or video recorded in one resolution and scaling it up to a higher resolution. A good upscaler can take a 1080p signal and output it at 4K. It may never look quite as good as a native 4K output, but whether or not you’ll see the difference depends on a number of factors, including the capabilities of your television and how far you sit from the screen.

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The screenshot above compares native 4K versus rescaled methods and comes from this article on the merits and uses of 4K compared with conventional 1080p. While the article focuses on shooting and editing video in 4K, many of its points about fine levels of detail and scaling artifacts are conceptually relevant to gaming. Upscaling is a way to capture a “good enough” level of detail without going all-out to render (or capture) huge amounts of content that the end user ultimately won’t see.

Actual developers have been coy about how they’re going to deliver 4K content to the PS4 Pro. Johan Anderrson claims that Frostbite 3 is using a custom method of delivering 4K that’s neither native “or” upscaled but something altogether different.

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We’ll have to wait to find out how all these pieces fit together, but it’s clear that the games Sony showcased as being 4K-capable aren’t all rendering at that resolution natively. That may bother some purists, but I’m not one of them. From my vantage point as a PC gamer, the dropped frames and inconsistent frame rates that have plagued both the Xbox One and PS4 this cycle are far more damaging than any modest resolution differences. I’m a PC gamer because I like choosing my own trade-offs when I have to balance detail levels and frame rates — but if I have to choose between them, I’d take a rock-solid 60 or even 30 FPS over higher detail levels with increased stutter.

Sony is going to give gamers more options to choose what kind of experience they want to have with the PS4 Pro, provided they own the right hardware in the first place — but that’s a subject for its own article. Early feedback from reporters who tested the PS4 Pro has been mixed, but there’s general agreement that if you own a UHD TV with HDR enabled you can look forward to a much nicer picture — while players with 1080p displays and standard display resolutions should enjoy better performance. Exactly how much better is still unclear, feedback on that front has been mixed. Either way, the PS4 Pro (mostly) won’t be pushing native 4K with its upgraded GPU. We don’t think that’s going to be a problem, provided the boosts to graphics quality are high enough in general.

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