Hi,
I’ve spent hours, probably months, tagging a very large music library. But I am still missing a lot of Year tags.
And then I discovered MusicBrainzPicard.
Please could someone walk me through the process of how to go through my entire library and add the Year tag, but I don’t want it to overwrite any other tags.
Is this possible? Sorry, complete novice to MBP here
I’m sure that it’s possible, but I can’t think of a simple way of doing it. In fact, the only way that comes to mind is to have one tagging script to save all of your current tags to temporary variables. This would need to be run manually while your files are still in the Cluster pane before matching them to tracks in the Album pane. Then a second tagging script that overwrites the tags retrieved from MusicBrainz with the values saved to the temporary variables in the first script. This would be run after the files are matched to tracks.
Whatever you try, I strongly recommend working with a copy of a few albums first to confirm that it’s doing what you expect.
Ahhhh. I had thought that this is exactly what MBP was intended for, but if you’re saying you can’t think of a simple way, that’s good enough for me.
I’ll carry on playing (as you say, with a copy of a sub-set) and see how it goes.
Many thanks,
Best wishes from the UK.
James, talk more with Bob. 
I would say load the library into MBP. If they have MBID’s then they should be moved to the right side. If so, then once all the data is loaded, select all the releases, and then go through the tag table and click use original value from the context menu for all the tags except for the year tags. I’m not in front of MBP, but I believe this is what I’ve done in the past for other tags that I want to modify, but not others.
If all the OP wants to do is add a year tag without touching any existing tags, I think the easiest way might be to add the tag manually. This could be done by adding it to the files and saving them while they are still in the Cluster pane, and never retrieve the Album information from MusicBrainz into Picard (so there’s no updated metadata to apply).
I might be able to develop a plugin to update only selected tags, to avoid the scripting that I suggested originally, but I’ll have to think about it a bit because it won’t be simple or straightforward to write. My first impression is that it will have to be done in two stages, and use three different APIs. It’s an interesting challenge, but I really wonder whether there is enough of a demand for such functionality or whether this is an isolated case.
Couldn’t you just add everything else to the “preserve tags” list?
Good catch! I believe you could. I forgot all about that setting.
That would avoid the scripting that I originally suggested. The only thing is that you would need to know all of the tags used in the files and input them all into the “preserve” list (but that would only need to be done once).
The other thing is that would not prevent adding any new tags from the MusicBrainz metadata. I assumed that the OP didn’t want any new tags added other than the date. EDIT: I suppose you might be able to use the Keep tags plugin in conjunction with this to remove any new tags (other than the musicbrainz_* tags).
Yeah, might need to add a few $unset() scripts for miscellaneous data from MusicBrainz. Also only needs to be configured once per tag.
@james3mc adding things to the preserve tags list only requires right clicking on the field in the bottom panel and telling Picard to add it. I think you could even do it with multiple fields at once but I’m not in a position to test right now.
Seems relevant: