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[Proposal] Disallow .png files to be used as backgrounds

posted
Total Posts
19
Sadu
91 posts
Joined February 2020
Topic Starter
Sadu
For background purposes, .png is not a very good choice compared to .jp(e)g files, as it takes up much more space, often going quite close to the 2.5mb limit which osu! allows, while .jp(e)g files often take up many times less space. .png only provides lossless quality, which is not really needed at all for illustrative purposes, as some crispness loss due to compression is unlikely to be noticeable. I propose adding another rule in the Ranking Criteria, which could be worded as follows:

The background image must use .jpg or .jpeg file format.
Stompy_
Beatmap Nominator
984 posts
Joined March 2020
Stompy_
I don't think it's needed to disallow them completely, not every png is troublesome and they can be compressed easily.
Sadu
91 posts
Joined February 2020
Topic Starter
Sadu
They provide no tangible benefit compared to .jpg files while they always take more filespace. This could just be a simple check made by MV. .png is just simply a lossless filetype, so allowing it would feel similar to use .wav or .flac files as song files, it is just taking up way more space to stay lossless.
Last edited by Sadu , edited 1 time in total.
Pasi_
292 posts
Joined July 2020
Pasi_

Sadu wrote:

For background purposes, .png is not a very good choice compared to .jp(e)g files, as it takes up much more space, often going quite close to the 2.5mb limit which osu! allows, while .jp(e)g files often take up many times less space.
it depends. while true for the majority of cases, PNG also supports compression, and in some situations it performs much better than JPEG compression, especially when the image consists of large areas with solid colors.

for example, the bg of this map (a .png file) is only 31 KiB. when converted to a .jpg file at max quality, the size increases to 523.6 KiB.

this would be another example. 720.8 KiB -> 824.9 KiB.

so i think straight up disallowing .png is not the right way.
Stompy_
Beatmap Nominator
984 posts
Joined March 2020
Stompy_
Also it's important to note that no matter what, background size limit is hard set to 2.5MB no matter if it's png or jpg.
Sadu
91 posts
Joined February 2020
Topic Starter
Sadu

Pasi_ wrote:

Sadu wrote:

For background purposes, .png is not a very good choice compared to .jp(e)g files, as it takes up much more space, often going quite close to the 2.5mb limit which osu! allows, while .jp(e)g files often take up many times less space.
it depends. while true for the majority of cases, PNG also supports compression, and in some situations it performs much better than JPEG compression, especially when the image consists of large areas with solid colors.

for example, the bg of this map (a .png file) is only 31 KiB. when converted to a .jpg file at max quality, the size increases to 523.6 KiB.

this would be another example. 720.8 KiB -> 824.9 KiB.

so i think straight up disallowing .png is not the right way.
Alright, those are good examples and .png really is better in these cases, though I believe these are still more extreme cases and this is not usually the case, so potentially it might be better as guideline then:

The background image should use .jpg or .jpeg file format. .png may be used if it has a smaller filesize than a converted .jpg or .jpeg file.
Pasi_
292 posts
Joined July 2020
Pasi_
yeah as a guideline it would be fine imo.
Nevo
Global Moderator
1,193 posts
Joined November 2015
Nevo
I don’t see a real need to make the rule more confusing for something that’s not a real big deal in the grand scheme of things.

Adding in an exception for usage of png where it may be smaller kinda nullifies the point of changing the rule.

At that point you might as well stick with the 2.5mb limit to keep it simple and straightforward for anyone to understand.
Sadu
91 posts
Joined February 2020
Topic Starter
Sadu
I feel that even keeping it as just all .jpg would be much better than the current state if you want simplicity, since in most cases .png will take at least 5x as much space as it would when converted to .jpg for absolutely no benefit
Sanch-KK
Beatmap Nominator
229 posts
Joined October 2016
Sanch-KK
Going through with adding this guideline will just waste everyone's time massively and overcomplicate things while providing no tangible benefit to the game. Both jpeg and png can be bloated, and current rule with hard cap on size already suffices. I can already see threads under qualified maps started by people i wouldn't want to name with hundreds of posts over yet another meaningless technicality. No thanks. Besides that, many people (including OP, since they had to be educated on cases where png performs better) don't even truly know the difference and sometimes have no idea how to convert from one file type to another. There's just no point
Last edited by Sanch-KK , edited 1 time in total.
Kurisu Makise
Beatmap Nominator
438 posts
Joined June 2013
Kurisu Makise

Sanch-KK wrote:

There's just no point
I Agree
Last edited by Kurisu Makise , edited 1 time in total.
tilda
Beatmap Nominator
338 posts
Joined March 2015
tilda

Sadu wrote:

I feel that even keeping it as just all .jpg would be much better than the current state if you want simplicity
personally feel like the current rules are quite simple, and the proposal makes it head in the opposite direction

taking an example from another section of the ranking criteria: audio files are heavily policed (i.e. hitsounds) because of technical limitations; hitsounding using mp3 files is not allowed (or only used on secondary/tertiary hitsounds at the very least). why? as the rc explains, mp3 files are "inherently delayed" - meaning, not good for hitsound feedback.

in comparison, png is a widely supported format that doesn't have any of those issues, and looking out for bloated/larger files is already encouraged as a guideline. many bns already check the folder for high filesizes and encourage/provide compressed files if needed (myself included).
Last edited by tilda , edited 1 time in total.
-Koyomi
364 posts
Joined June 2015
-Koyomi
sanch is right
snomi
161 posts
Joined May 2019
snomi
bns already check for bg file bloat + this is pointless and only causes more issues for bns to check without reason or benefit

2.5mb limit is good for any size as is, everyone else in more detail explained how jpeg isn't always better too

also, as someone who makes custom backgrounds, jpeg only hurts my background quality, especially when working with pixel art it looks bad.

i like my work to be seen in full quality when possible, and alongside the map can be downloadable in full quality.

I don't like this change idea at all
Last edited by snomi , edited 1 time in total.
pw384
Beatmap Nominator
2,322 posts
Joined January 2012
pw384
Keep in mind that .jpg compression is lossy, and the distortion is occasionally very visible when it involves huge contrast in different color channel. For this reason, I believe the proposal doesn't help anything but might cause further troubles

Also keep Occam's Razor in mind - we should not add any complexity when there is no need to do such...
Last edited by pw384 , edited 1 time in total.
Neto
Beatmap Nominator
1,327 posts
Joined October 2014
Neto

Sadu wrote:

I feel that even keeping it as just all .jpg would be much better than the current state if you want simplicity, since in most cases .png will take at least 5x as much space as it would when converted to .jpg for absolutely no benefit
You haven't considered cases where people will use a small png file for ranking purposes (FULLHD or QHD) but will later on replace it with 4k images of the same art using png as file because they want the best quality on their end. Disallowing .png has no real benefits because the rule was created to disallow huge images with bloat. I know because I vetoed Vinxis map that had a huge bg file for no good reason before this rule even existed.

Btw if you want to save people space the current offender is not bg files, but custom hitsound .wav files that could be replaced with .ogg files to save space, but good luck with that.
Spy
Beatmap Nominator
2,577 posts
Joined November 2011
Spy
I don’t think we would run into any extra issues, like insufficient space, because of such a small file size. Besides, PNG and JPG display colors quite differently.

In the current environment, many people are very particular about audio quality but need it to be between 128 to 192 kbps to comply with RC. In the end, many switch to using .ogg to retain 320 kbps quality while saving space, which is the most ideal solution.

Now, taking images as an example, can you find a format that allows the BG to be displayed at the highest quality without increasing unnecessary file size to address the concerns you mentioned?

As it stands, there isn’t one. Whether you ban PNG or make it a guideline, it will likely provoke pushback, and such proposals haven’t been accompanied by any measures to actually improve the situation, they simply point out the problem and require everyone to change accordingly.

Disagree.
momoyo
Mapping Architect / Elite Nominator
282 posts
Joined June 2018
momoyo
This seems overly bothersome for all parties involved in the ranking process.

Everyone might agree that .png have more size than .jpg/.jpeg but that's not really a big of a deal considering there's a limit cap allowed for background sizes as you mentioned.

Also like Neto said, one of the major things that cause a big increase of filesize tend to be usually hitsound files being .mp3 over .ogg

I wouldn't enjoy placing more regulations about such things honestly, just my opinion though.
Moebytes
46 posts
Joined July 2018
Moebytes
Jpeg artifacts are really noticeable to me. I would prefer to opt for better quality as long as its under a reasonable limit than save an extra MB. If space is really an issue could support lossless webp over png (I don't know if beatmaps already support it).
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