4K video only plays at 1080p resolution

Trying to test my display’s 4K capability on YouTube when I notice that (both on Chromium and Firefox) the video looks just as blurry as if it was set at 1080p quality when actually on 4K quality as per YouTube. I am pretty sure that it’s not playing the video in 4K. This problem does not occur on MPV. How do I fix this?

System info: https://0x0.st/XbG4.txt

do you use any extensions in firefox/chromium ?


maybe enhancer for youtube…

You can launch firefox with extensions disabled (there is a way in the menus i think)

you should try

(i think it is under help->repair mode or something like that)


Didn’t work. Even on Thorium without any extensions.

is media.mediasource.webm.enabled set to true when you check about:config in firefox? (and running it with extensions)

and same video played with mpv displays in 4k right ?

ok nvm i’m dumb the 4k video looks as blurry due to chromatic aberration. other “4k” videos on youtube have compression which i neglected.

Not all 4K content on YouTube necessarily warrants it. A classic example is lower resolution content that’s been upscaled (1080p > 4k), which seems to be pretty common practice.

4k video is capable of 4x (400%) higher details than 1080p, but upscaled content is never going to achieve anything remotely close to that, and is likely barely perceptible. The only benefit to that seems to come down to perceived compression artefacts, which are arguably less noticeable at the higher resolutions.