Audio
What is a .m4b file?
A .m4b file is a MPEG-4 Media File. This is an audio format. Confusingly, this extension has been used by 2 different formats over the years — they're all listed below.
This extension has been used by more than one format
2 different formats have claimed .m4b over the years, so two files with the same extension aren't necessarily the same kind of thing.
How to open a .m4b file
- VLC plays almost every audio format ever made.
- Audacity opens it for editing.
The registry records this extension against MPEG-4 Media File, M4A Audio, so software from that family is the most likely match.
How to convert a .m4b file
- Export as .mp3 from Audacity or VLC for maximum compatibility.
MIME type
When a .m4b file travels over the web, servers label it with one of these MIME types:
application/mp4video/mp4audio/mp4The technical record
For archivists, developers and the merely curious: these are the PRONOM registry entries for .m4b.
| Format name | Version | MIME type | PUID |
|---|---|---|---|
| MPEG-4 Media File | — | application/mp4, video/mp4 | fmt/199 |
| M4A Audio | — | audio/mp4 | fmt/2094 |