I’ve searched many times, and the best answers I get are sort of ambiguous. The support articles give me very little assistance, referencing only four of the many tags available.
If your content already has (accurate) embedded metadata, then Plex will use that information for matching in a default install.
and
Besides having the files organized appropriately, tagging your tracks correctly can influence how well they are identified and matched. Ideally, you’ll want your tracks to have accurate “Artist”, “Album”, and “Track” tags. The “Album Artist” tag can also be very useful in cases of compilations … If you’ve enabled the Prefer local metadata advanced preference for your music library, then you must ensure that all of your music content has full, accurate metadata tags.
I know for sure that Plex also reads “genre” tags, as well as at least one of the “Year” or “Date” tags, because changing any one of those tags is reflected in Plex when you refresh the metadata.
It seems this is a well-guarded secret, because my searches for more information always end up with something like “Plex may or may not use other embedded tags”
I can’t imagine a reason for Plex to decide this information should not be revealed. The new music system is a big improvement over the old,(with a few glitches here and there) If we, as users, were able to utilize the tags that Plex actually uses, it could eliminate some of the mis-matches and unmatched artists and albums that seem to occur more often than they did with the old system.
