Combining .mp3 into .m4a Audio

[mgriebling]

There is a setting to combine mp3 files into a single m4b audio book.
Is there a way of just combining mp3 files in one directory into an audio book.
I have multiple directories containing mp3 files and would like one book (m4b file) per directory.
It's somewhat tedious to do this one directory at a time but it would be nice to do a batch of directories and
produce a set of books automatically. Is this possible?

[mjb2010]

I am not the developer, but although this is technically possible (MPEG-4 containers are allowed to contain MP3 streams), the resulting M4B would be nonstandard, to the extent Apple gets to define what M4B implies, so I'd expect that many devices won't know what to do with it.

You can, of course, use MP3s as the source for a standard AAC-based M4B, e.g. as mentioned at https://www.reddit.com/r/audiobookshelf/comments/1954wki/comment/nq0adtm/

Not sure if batch processing is an option.

[mgriebling]

Thanks for the info. I did find an App called fre-ac that does exactly what I needed. M. Griebling

…

On Aug 29, 2026, at 14:09, Mike J. Brown ***@***.***> wrote: I am not the developer, but although this is technically possible (MPEG-4 containers are allowed to contain MP3 streams), the resulting M4B would be nonstandard, to the extent Apple gets to define what M4B implies, so I'd expect that many devices won't know what to do with it. You can, of course, use MP3s as the source for a standard AAC-based M4B, e.g. as mentioned at https://www.reddit.com/r/audiobookshelf/comments/1954wki/comment/nq0adtm/ Not sure if batch processing is an option. — Reply to this email directly, view it on GitHub <#808?email_source=notifications&email_token=AASPEZBGJMZS36RFQGHC3AT5MML4BA5CNFSNUABIM5UWIORPF5TWS5BNNB2WEL2ENFZWG5LTONUW63SDN5WW2ZLOOQXTCOBSGAYDQNRQUZZGKYLTN5XKMYLVORUG64VFMV3GK3TUVRTG633UMVZF6Y3MNFRWW#discussioncomment-18200860>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AASPEZFYQOP56MQSA5UOSHL5MML4BAVCNFSNUABIKJSXA33TNF2G64TZHMYTAMBYHA2DCMBZHNCGS43DOVZXG2LPNY5TCMBUHE4DMOBWUF3AE>. You are receiving this because you authored the thread.