Comment 5 for bug 882947

> the idea of the DB presenting a different view to the user than what
> is actually in the file is a bit disturbing to me.

Well pretty much all players do this to some extent - things like rating and playcount are almost never stored in tags (for good reason), only in internal DBs. The fact that we apply this to all metadata, including tags, is in part an artifact of how most of the code doesn't distinguish between internal tags and external tags for the sake of internal simplicity and consistency. Many other player also do not allow editing of arbitrary tags as we do, only a fixed set of allowable tags, which is generally a subset of the set of tags which can be stored in all the tag formats the player supports, so the issue cannot actually arise for them.

Perhaps we could add a visual indicator in the tag editor about whether a given tag is actually capable of being written to the file or not? Just an icon next to the field (with an explanatory tooltip) should suffice. This probably requires exposing more info from xl.metadata however, since at the moment there's no way to know what tag format a given Track uses or what tags can be written to a given format.