Multiple value artist tag in m4a not showing in musicbee

I have an mp4 (m4a) music file. Picard will tag the Artist field to be multiple value (several artists), each separated by semi-colons – when you edit the tag in Picard, each artist appears on separate lines, so the semi-colon is indicating a separate Artist tag. In mp3tag, that music file is confirmed to have multiple artist tag values.

In musicbee, the artist tag for that music file appears blank (null).

Has anyone encountered this? I can manually “solve” the problem by editing the Artist field in Picard to eliminate the artists on separate lines, and put all the artists on one line, also separated by a semi-colon (then it appears in MusicBee as multiple artist tags), but I was hoping for a way not to have to do that.

Perhaps I should ask this in a separate post, but as an interim solution, is there a script I can run that would convert a field like Artist that has multiple values (artists), each separated by semi-colons and producing multiple identical Artist tags, to a field that is one line (produces one tag), with each item separated by a semi-colon? The latter alone is what MusicBee seems to treat as a multiple value tag, at least for mp4 (m4a) files. (The MusicBee way has the advantage of showing all values of the multi-tag in Apple iTunes. The Picard way does not; it shows only the first value or artist.) Thank you.

p.s. This may (or may not) be relevant – it appears mp3tag made special changes to read Picard’s multi-value tags (in mp4 files):

There is also this ticket:

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As you found out, yes, people are aware that Picard writes m4a tags that aren’t compatible with software not based on mutagen.

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@yindesu Thank you for confirming that, I’ll submit an enhancement request on it or I guess follow up on ticket PICARD-376.

Does anyone happen to know if there is a script or command or tool that would convert Picard fields that have multiple values (and produce multiple identical tags) into fields that are one line (produce one tag) with each item in the tag separated by a semi-colon? The latter fields would be compatible with MusicBee (and even itunes, at least as far as displaying all values).

As Picard by default doesn’t write the artist tag multi-valued you likely already have some script to set it. You probably have something like this:


If you use $set instead it will flatten the lists of artists into a single semicolon delimited entry.

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@outsidecontext Picard does actually set my artist to multi-valued when it does a lookup, for whatever reason, could be a plug-in I’m using. But thank you! running $set(artist, %artist%) reverses that. I’ll try to set up a script to reverse all multi fields it finds.

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