The music industry needs to more widely use some kind of equivalent to the ISBN that the book industry uses. A simple "ISMN" list per playlist/library would be all that would be needed to move between services when both apps have the same songs.

One could also imagine a standardized ismn://<number> URL format that could open in your preferred music app, and this could work even without a streaming service if you already own that song in your personal music collection.

ISMN seems to exist: https://www.loc.gov/ismn/about.html

But, I've never actually seen it used for recordings, it seems to be focused solely on music notation. So, some kind of recording-focused identifier for keeping track of specific performances between services.

Yeah, but the next step is to make identifier somethink like a has so the media can be content addressable.

Wait, we can't have that. It's too convenient

Now we just need to associate payment/attribution related metadata with those identifiers

Content addressable doesn't really work here... different apps may have the same recordings encoded in different formats and bitrates, but they are still the same recording. Unless you meant "content addressable" in the sense of a uniquely assigned identifier like I was already talking about, and not a computed identifier from the raw bytes of the file like a hash.

This sounds like an acoustic fingerprint, such as AcoustID[0]. I think AcoustIDs and XSPF[1] would be a good combination for shared playlists. It's a shame that development stopped on the Tomahawk music player[2], it would have been an ideal platform for shared playlists like this.

[0] https://musicbrainz.org/doc/AcoustID

[1] https://en.wikipedia.org/wiki/XML_Shareable_Playlist_Format

[2] https://github.com/tomahawk-player/tomahawk

They’re called magnet links.

MusicBrainz has also been making a list of unique identifiers for music tracks: https://musicbrainz.org/

This exists and is called ISRC. This metadata is embedded in a subchannel on CD's.

https://en.wikipedia.org/wiki/International_Standard_Recordi...

Cool, I didn’t know that. I wish it were actually used by the various music apps.

It's a pity that compression is likely to provide subtly different data under different network conditions. If everything were lossless we could just use hashes as identifiers and proceed without the participation of the apps.

After all, they have no incentive to make this easy for us.

This is actually a beautiful idea. It'd definitely be possible for music purchased through bandcamp since lossless is generally available for most releases. Commenting to bookmark this.

> I wish there was some kind of vendor-neutral import/export format rather than requiring a third party to solve the whole matrix of integrations.

"vendor-neutral import/export format" sounds like the definition of third party. It's not that there shouldn't be a third party, it's that spotify etc. should adopt it.