---
title: ".m4b file — what it is and how to open it"
description: "A .m4b file is a MPEG-4 Audiobook. An audiobook file that remembers your place and supports chapters. How to open one on Windows, macOS and Linux, and what to convert it to."
url: https://atoneplace.net/file/m4b/
site: "At One Place"
---

# .m4b files

**.m4b file: MPEG-4 Audiobook**

An audiobook file that remembers your place and supports chapters.

## What opens a .m4b file

- **Windows:** VLC, foobar2000, Media Player (built in)
- **macOS:** Books (built in), Music (built in), VLC
- **Linux:** VLC, Cozy, mpv

## What a .m4b file is

M4B is an MP4 audio file flagged as a book, which is what makes Apple Books and podcast apps store a bookmark and show chapter navigation. Rename it to .m4a and it still plays, but you lose the position memory that makes it useful for a twelve-hour recording. Audible's own .aax files are a different, DRM-protected format that only Audible apps open.

## Converting it

A .m4b file is commonly converted to .mp3, .m4a, .wav or .aac. It is a binary format, so a text editor will show unreadable characters rather than its contents.

## Details

- **Extension:** .m4b
- **Full name:** MPEG-4 Audiobook
- **Category:** Audio
- **MIME type:** audio/mp4
- **Created by:** Apple
- **Format:** Binary

## Common questions

### How do I open a .m4b file?

On Windows use VLC; on macOS use Books (built in); on Linux use VLC. An audiobook file that remembers your place and supports chapters.

### What is a .m4b file?

MPEG-4 Audiobook. M4B is an MP4 audio file flagged as a book, which is what makes Apple Books and podcast apps store a bookmark and show chapter navigation. Rename it to .m4a and it still plays, but you lose the position memory that makes it useful for a twelve-hour recording.

### Can I convert a .m4b file?

Yes. It is usually converted to .mp3, .m4a, .wav or .aac, either by exporting from one of the programs listed above or with a format converter.

## Related pages

- [.mp3 — MPEG-1 Audio Layer III](https://atoneplace.net/file/mp3/)
- [.wav — Waveform Audio File](https://atoneplace.net/file/wav/)
- [.m4a — MPEG-4 Audio](https://atoneplace.net/file/m4a/)
- [.flac — Free Lossless Audio Codec](https://atoneplace.net/file/flac/)
- [.aac — Advanced Audio Coding](https://atoneplace.net/file/aac/)
- [.ogg — Ogg Vorbis Audio](https://atoneplace.net/file/ogg/)
- [.opus — Opus Audio](https://atoneplace.net/file/opus/)
- [.mid — MIDI Sequence](https://atoneplace.net/file/mid/)
- [.m3u — Media Playlist](https://atoneplace.net/file/m3u/)
- [.wma — Windows Media Audio](https://atoneplace.net/file/wma/)
- [.aiff — Audio Interchange File Format](https://atoneplace.net/file/aiff/)
- [.amr — Adaptive Multi-Rate Audio](https://atoneplace.net/file/amr/)

## Sources

- Media Types Registry — IANA (https://www.iana.org/assignments/media-types/)
- Official vendor product documentation — At One Place (/about/)