So I listen to this really nice mashup artist named Oneboredjeu. Most of their work is hosted on their YouTube channel, but also as standalone releases on filehosts.
The issue is that the meta tags don’t quite line up between the video and the music file.
On the video, the title format is “Mixup Name - Artist 1 x Artist 2,” usually with the instrumentals of Artist 1 on the acapella of Artist 2.
On the file, however, the album name and track artist are the same as the original instrumental artist’s, and the vocal artist is in the track title as a feature.
If there’s no one most common track title then you need to pick one or the other; I would go with the one which best identifies the recording. In my opinion that would be the first option, which makes it clear that it’s a mashup and not a release by Sia as such.
…oh, I guess there’s a guideline that supports the first option also:
"If a recording is a mash-up of two (or more) recordings the artist should be set to the mash-up artist. Put the two “versus” artist titles into the recording name like so: “Track Title (Artist A vs. Artist B).” ( https://musicbrainz.org/doc/Style/Specific_types_of_releases#Mash-ups )
Based on the MB definition it doesn’t seem at all like a mixtape. It’s more similar to a remix - in as much as both are the work of a dj or producer creating something new from existing recordings - but I don’t know whether it’s standard practice to tag mashups with the “remix” secondary type.
