You must use the Source field if the song comes from or is directly tied to another media such as a video game, movie, series, etc.
"If the song was featured or tied to a media after it was released, the source field is optional. "
These 2 implies if the song is tied to a game you
may use osu! as source, cuz it's technically tied to the osu! game.
As for the "the song is from other place" thing tho, I would honestly suggest not allowing osu! in source at all if it directly ties to another game and osu! licensed it later, say for example, Dynamix / SOUND VOLTEX etc. That would solve "the songs are not from osu!" problem.
Sonnyc wrote:
As a BN checking maps, I’d say it’s adding some unnecessary workload because it’s really confusing to track where the true origin of a song belongs to.
imo that's a necessary job as a BN
Sonnyc wrote:
If a song is features in multiple rhythm games like Dynamix, osu!, Arcaea, Sound Voltex etc, it’s pretty complicated to know for which game the song was composed exclusively.
People can use the first released game as the source. In fact, if it is directly tied to a game at first, that game should be used in the source, even if osu! licensed it later.
Sonnyc wrote:
It’d be very weird to see bundled maps with official licensing having another rhythm game as a source.
It's weirder if it originally comes from another game and osu! licensed it later, and it becomes bundled. Other people may think osu! is stealing the credit, and it doesn't help with the professionality either.