1

My neighbor insists that a $75 22" (as of 2024) HDMI display that is advertised as 1080p is 4K because his Xbox asks to enable 4K gaming when he uses it. It probably just accepts a higher resolution than it natively supports, since I know many of my older LCD displays will do that.

But that brought up the question about the use of subpixels when scaling. 1920x1080 RGB is actually 5760x1080 if the individual colors are considered. It could actually be scaling 3840x2160 or 4096x2160 in to 5760x1080.

Do typical flat screen monitors do this? Maybe just high end ones? What about projectors? The color wheel based projectors wouldn't be capable of subpixel rendering but there are LCD projectors. So could there actually be an advantage to using 4K on a 1080p display?

I came across this document about "Subpixel-based image downsampling algorithm [...]" but I'm not sure if it would be relevant to this situation or not. https://ietresearch.onlinelibrary.wiley.com/doi/pdfdirect/10.1049/iet-ipr.2013.0325

Improve this question
1
  • 1
    Monitors don't do this - Windows does.
    – harrymc
    Commented Jan 22 at 19:44

1 Answer 1

Reset to default
2

Normal output devices like monitors or projectors don't do any scaling/smoothing/rendering themselves - the Xbox handles all that on its own. In this case, it's a feature called supersampling:

What is Supersampling?

If there’s one thing I’d love for you to take away from all this information is this: a 4K screen is not required to play great games on Xbox One X. Your games will still look and run much better on Xbox One X than any other console on the market regardless of your television and that’s thanks to supersampling. Supersampling also helps to reduce “jaggies” around the edges of objects and other staircasing-like effects

Think of supersampling as the cousin of upscaling. Instead of taking a lower resolution image and blowing up (creating a distortion) like upscaling’s effect, supersampling takes a high-resolution image and scales it down to your television’s native resolution — be it 720p or 1080p — to bring all the information that Xbox One X is pouring into its games and beaming to the screen.

More details from the Xbox PR here:

https://news.xbox.com/en-us/2017/11/03/xbox-one-x-explaining-4k-hdr-supersampling/

Note that some 'smart' TVs can do similar things like upscaling, but it's generally in the reverse direction (1080p to 4k) and not as good.

Edit for comment: Monitors accepting higher resolutions is a separate thing, and not exactly standard across monitors. It also heavily depends on the display protocol (VGA/DVI vs HDMI/DP) as newer protocols tend to "handshake" on supported resolutions instead of mostly guessing.

It sounds like your lcd display/projector will skip or merge some percentage of pixels in order to fit the video source, which is common. Other monitors will crop, overscan, only display what they have pixels for, or simply complain with a message like "out of range".

In short, your neighbor's HD TV is not displaying 4K pixels, but supersampling (done by the xbox, not the monitor) can make it look more accurate than 1080p would otherwise.

Improve this answer
3
  • My projectors and LCD monitors will accept resolutions other than their native ones. They do scaling. My 1280x1024 will accept up to 1600x1200 even though it looks quite bad. How the scaling works is what I'm wondering.
    – Alex Cannon
    Commented Jan 23 at 20:22
  • @AlexCannon that's a different behavior you usually only see with analog inputs. I've added some more details to my answer
    – Cpt.Whale
    Commented Jan 23 at 21:14
  • Almost every display (TV or otherwise) accepts input at lower-than-native resolutions and most certainly will upscale. Upscaling, as the name suggests, takes a lower resolution and makes a higher-resolution image.
    – Daniel B
    Commented Jan 23 at 21:25

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .