system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are 4K videos more crisp that 1080p videos even when the native screen resolution is 1080p?

I notice this a lot when watching YouTube videos on my pc.
gpt
This mainly has to do with how 4k gives you more bitrate (in the context of youtube), or how much less compressed the video gets when it arrives for you to watch. You know how you can compress a jpeg image to shrink the file size but make it less detailed even though the physical dimensions of the image stays the same? Youtube does mostly the same thing, but to the video instead. When you chose 4k instead of 1080p youtube doesn't compress the files as much when it gives it to you to watch, thus leading into a better video even though the physical dimensions of the video for you is the same (at 1080p)