Is there a way (scripting?) to derive tags from other tags?
I intend to keep a “canonical” set of files with their correct tag values eg album, date.
Then, for each file, add my own additional (eg prefixed) field for album and year reflecting the song’s original release.
Then copy those files to a “pragmatic” file-set (folder) where eg the plain-standard album and year are replaced by the latter, the original values being (just prior to this) copied to additional custom (and prefixed) fields for actual release album and year.
The reason for doing this is to satisfy (make the pragmatic file-set easier to use with) a playout system that (in its easiest mode - which I want to be able to mostly use!) only recognises the standard album and year etc. fields (in ID3).
If I understand you correctly, I think you can accomplish this by using a tagging script to create new tags with the original values and then updating the original tags to your desired values. Something like:
$set(album,your new album name)
You can also update the standard tag values manually in Picard if you don’t want to set the new values using a script.
This way the original values are stored in the files, and your custom values are stored in the standard tags and can be used for file naming and such. No need to keep separate files.
EDIT: I just re-read your original message. Basically what I suggested would be applied to a copy of the original “canonical” set of files, thus producing your “pragmatic” file set.
Perfect, thank you, that clears my mental friction in getting started. I’ll learn more and play with this.