What is a .m4b file?
A .m4b file is an MPEG-4 audio. Its registered MIME type is audio/mp4, which places it in the audio family of formats.
M4B is a binary format: the contents are not readable text, so opening it in a text editor shows scrambled characters.
The same format is also saved with the extensions .f4a, .m4a, .mp4a.
M4B file format details
| Extension | .m4b |
|---|---|
| Format | MPEG-4 audio |
| MIME type | audio/mp4, audio/x-m4b |
| Category | Audio |
| Text or binary | Binary |
| File signature | None fixed |
| Registered with IANA | Yes |
| Other extensions | .f4a, .m4a, .mp4a |
How to open M4B files
| Windows | VLC media player is free and plays almost every audio and video format, M4B included in most cases. Media Player and Films and TV handle the common ones. |
|---|---|
| Mac | QuickTime Player plays formats Apple supports. VLC or IINA play most others. |
| iPhone and iPad | The Files app plays formats Apple supports. VLC for iOS plays most others. |
| Android | Most gallery and music apps play common formats; VLC for Android plays almost everything. |
Convert M4B files
TapToConvert converts M4B files in your browser, without uploading them. Open the M4B converter, or go straight to a conversion:
M4B file FAQ
What is a .m4b file?
A .m4b file is an MPEG-4 audio, with the MIME type audio/mp4.
How do I open a .m4b file?
VLC media player plays most audio and video formats on Windows, Mac, iPhone and Android.
Is a .m4b file safe to open?
M4B files hold data rather than programs, but any file from an unknown source can be crafted to exploit the software that opens it. Keep that software up to date. The viewer on this page only reads the bytes and never runs anything.
What is the MIME type of .m4b?
audio/mp4, and it is also seen as audio/x-m4b. Web servers send this type so browsers know how to handle the file.
Is M4B a text or binary format?
Binary. Its contents are not readable as text.
File type facts come from the IANA media type registry, the mime-db project and the freedesktop.org shared MIME database.