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After some initial discussion in the QAT discord, we confirmed from a dev that there is actually no hard cap in background resolution (you can perfectly upload higher resolution backgrounds, it won't break anything).

Currently the maximum resolution for storyboard elements is 4k anyways (this was intended to help scrolling backgrounds).
However, this means that currently, you are not allowed to set a 4k background, but if you make it a storyboard element, and set it over top of your map, you can "technically" have a 4k background anyways.

So this is obviously kind of pointless; Why not just raise the cap of background images to 4k?

4k monitors are getting more and more popular, in fact right now the ideal gaming monitor should be 2k (1440p) and 144hz.
In fact; I, myself own a 2k monitor, while I don't play full screen, there are definitely people out there who do, and would end up having their 1080p background being upscale.

Tldr; We should raise the bg resolution cap to 4k, if not, 2k
The biggest worry is file size I guess. Anything bigger than 1080 should probably be restricted to jpg instead of png.
If possible I'd like to get peppy's opinion on the matter about filesize.

Rather than restricting it to jpeg, we could do a hardcap on BG filesize instead (say like 10mb)
edit: but then again, osz size already gets capped so.. is there even a point? as long as the total osz is small enough to be uploaded i don't really see a point
are we talking UHD 4k cinema grade, or consumer grade? there's considerable difference in the sizes of the two

i'm also not sure what demographic of the osu! playerbase would benefit from 4k backgrounds aside from them artificially inflating beatmapset sizes - do remember that a lot of people who play osu! do so from places with substandard internet

2k/1440p might be a possibility, but 4k just seems excessive. i can already see the use case for 2k being pretty thin at best
that's understandable, I'm not really trying to encourage everyone to change their bg to 4k either, just want to open up some restrictions because many of the source art on pixiv or w/e are much larger than 1920 x 1200, so having that bigger leeway to be able to upload original quality would be better imo?

2k is a good compromise for me too, since personally i use a 2k monitor here, and osu does seem to support resolutions up to 2k?
If you raise the maximum background size to 4K, everyone will be asking mappers to raise their resolution to the maximum allowed. Same as how people ask mappers to raise their resolution to 1920x1200 or 1920x1080. I think its counterproductive. And my question is, is this added detail even needed? Can the difference between 4K and 2K, 2K and 1080p, or 4K and 1080p really be noticed? If its barely noticeable is it really worth the increase in file size?
Instead of caring about how many pixels an image has, I think it's more important to assess the image size, since there are many ranked 1080p backgrounds with larger file sizes than 4k backgrounds, and there are many ranked 768p backgrounds with larger file sizes than 1080p backgrounds.

Limit the image size instead, since when a background's file size is too large, there will be a slight delay before osu! shows it. This already happens with ranked 1080p backgrounds, so I guess my computer isn't powerful enough to drive modern osu! backgrounds.

Again, limiting resolution does not make sense, since some 4k backgrounds will have smaller file size than 1080p ones. This prevents 4k, 1440p, and other users from benefiting even when the file size is relatively small. Also, if you're compressing your backgrounds anyway, like you're supposed to do, file size should not be an issue.

Source: I own a 4k display.
I was initially concerned about performance for higher resolution images since they take longer to load ingame, but did some testing and it only applies to resolutions that are much higher like 12000x8000 or whatever. osu runs pretty slow on osx so should be fine as a lower end performance measure.

Agreed that adding a size limit to bgs would be helpful. I think 3mb is a reasonable limit. (imo 2mb for 1080p but idk how large 2k files are)

tatatat wrote:

If you raise the maximum background size to 4K, everyone will be asking mappers to raise their resolution to the maximum allowed.
This will not happen because lower resolutions still have a larger market share than 2k. In 5 years I would expect that would be the norm, but it's not going to be happening right now.
i guess we can go with 2560x1440, though i wanna see some action on https://osu.ppy.sh/community/forums/topics/853985 first
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