I use a 1080p monitor and what I’ve noticed is that once creators start uploading 4k content the 1080p version that I watch on fullscreen has more artifacting than when they only uploaded in 1080p.
Did you notice that as well?
Watching in 1440p on a 1080p monitor results in a much better image, to the detriment of theoretically less sharper image and a lot higher CPU usage.
Turns out, I have an old dumb FullHD TV that should be ideal for this experiment. So, if I watch a YT video on 1080p, I should be able to see compression artefacts that are invisible when using a higher resolution. How is that supposed to work anyway, given that the browser knows the output resolution? Will it just download a higher resolution video, drop every other pixel, and display the rest?
Yes, just like it can show a 1080p video not in fullscreen :)