# "MusicBrainz Composer Id" not mapped for MP3
**URL:** https://community.mp3tag.de/t/musicbrainz-composer-id-not-mapped-for-mp3/71933
**Category:** General Discussion
**Tags:** feature
**Created:** [October 8, 2026, 1:09pm UTC](https://community.mp3tag.de/t/musicbrainz-composer-id-not-mapped-for-mp3/71933 "2026-10-08T13:09:29Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@squonk57](https://community.mp3tag.de/u/squonk57)
#### Post date: [October 8, 2026, 1:09pm UTC](https://community.mp3tag.de/t/musicbrainz-composer-id-not-mapped-for-mp3/71933/1 "2026-10-08T13:09:29Z")
As the title says, there is no mapping for [MusicBrainz Composer ID](https://picard-docs.musicbrainz.org/en/latest/appendices/tag_mapping.html#musicbrainz-composer-id).
I tried to add a user defined mapping from "TXXX:MusicBrainz Composer Id" to MUSICBRAINZ\_COMPOSERID. That works on import, but writes the frame description back as "TXXX:MUSICBRAINZ COMPOSER ID" in upper case, which is then no longer recognized by MusicBrainz Picard.
(The latter can be mitigated by enabling "Reuse unmodified ID3v2 frames" if the file has originally been tagged with Picard, but at present it is not possible to add a missing Composer ID directly from Mp3tag.)
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### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [October 8, 2026, 1:22pm UTC](https://community.mp3tag.de/t/musicbrainz-composer-id-not-mapped-for-mp3/71933/2 "2026-10-08T13:22:35Z")
Could you try an action of the type "Case conversion" for `_FIELDNAME` and the setting "Mixed case" and see if you get a better result?
> **[Case Conversion – Mp3tag Documentation](https://docs.mp3tag.de/actions/case-conversion/)**
>
> Documentation on the Case Conversion action type that can be performed as Quick Action or as reusable workflow from Action Groups. Mp3tag is the universal Tag Editor.
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### Author:  [@LyricsLover](https://community.mp3tag.de/u/LyricsLover)
#### Post date: [October 8, 2026, 1:27pm UTC](https://community.mp3tag.de/t/musicbrainz-composer-id-not-mapped-for-mp3/71933/3 "2026-10-08T13:27:29Z")
I can not reproduce this behaviour.
If I enter a new field manually in Mp3tag, I can see it in MB Picard:
Added some text "from Picard" in MB Picard and saved into my test track, I can see it back in Mp3tag as expected:
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### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [October 8, 2026, 1:28pm UTC](https://community.mp3tag.de/t/musicbrainz-composer-id-not-mapped-for-mp3/71933/4 "2026-10-08T13:28:53Z")
> [@squonk57](#):
>
> As the title says, there is no mapping for [MusicBrainz Composer ID](https://picard-docs.musicbrainz.org/en/latest/appendices/tag_mapping.html#musicbrainz-composer-id).
I'll add this with the next release. Thanks for pointing!
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### Author:  [@squonk57](https://community.mp3tag.de/u/squonk57)
#### Post date: [October 8, 2026, 1:36pm UTC](https://community.mp3tag.de/t/musicbrainz-composer-id-not-mapped-for-mp3/71933/5 "2026-10-08T13:36:54Z")
Thanks for the suggestion. That lets me change the field _contents_ (i.e. "7a8dbe84-f4c0-4457-bfa3-edced1f8cde0" ↔ "7A8DBE84-F4C0-4457-BFA3-EDCED1F8CDE0"), not how the frame _name_ is stored.
Basically this is the same as [Writing back MusicBrainz IDs in all Uppercase?](https://community.mp3tag.de/t/writing-back-musicbrainz-ids-in-all-uppercase/18405) , just with another frame.
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### Author:  [@squonk57](https://community.mp3tag.de/u/squonk57)
#### Post date: [October 8, 2026, 1:40pm UTC](https://community.mp3tag.de/t/musicbrainz-composer-id-not-mapped-for-mp3/71933/6 "2026-10-08T13:40:50Z")
Your screenshot shows the exact problem 😉
It should show up in Picard as "Composer MBID", not as "MUSICBRAINZ COMPOSER ID".
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### Author:  [@LyricsLover](https://community.mp3tag.de/u/LyricsLover)
#### Post date: [October 8, 2026, 1:46pm UTC](https://community.mp3tag.de/t/musicbrainz-composer-id-not-mapped-for-mp3/71933/7 "2026-10-08T13:46:59Z")
How do you set this "Composer MBID" manually in MB Picard?
AFAIK there is no such field name in "Add new Tag" in MB Picard.
Do you use any addon for this purpose?
(Or do you use the brand new released MB Picard v3.0.1?)
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### Author:  [@squonk57](https://community.mp3tag.de/u/squonk57)
#### Post date: [October 8, 2026, 1:53pm UTC](https://community.mp3tag.de/t/musicbrainz-composer-id-not-mapped-for-mp3/71933/8 "2026-10-08T13:53:11Z")
Sort of ... I'm using 3.0 - I didn't even know that 3.0.1 is already out 🙂
It might indeed be new in version 3. It's right there with the other musicbrainz\_\* tags:
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### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [October 9, 2026, 3:37pm UTC](https://community.mp3tag.de/t/musicbrainz-composer-id-not-mapped-for-mp3/71933/9 "2026-10-09T15:37:35Z")
> [@squonk57](#):
>
> there is no mapping for [MusicBrainz Composer ID](https://picard-docs.musicbrainz.org/en/latest/appendices/tag_mapping.html#musicbrainz-composer-id)
I've added the mapping with [Mp3tag v3.37-beta.1](https://community.mp3tag.de/t/455).
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### Author:  [@squonk57](https://community.mp3tag.de/u/squonk57)
#### Post date: [October 9, 2026, 10:54pm UTC](https://community.mp3tag.de/t/musicbrainz-composer-id-not-mapped-for-mp3/71933/10 "2026-10-09T22:54:14Z")
It works! Thank you 🙂