M4B File Documentation

Overview

Feature Value
File Extension .m4b
Full Name MPEG-4 Audio Book File
Format Type Audio
MIME Type audio/mp4
Main Usage Audiobooks, Podcasts
Based On MPEG-4 Part 14
Compression Lossy (typically AAC)
DRM Support Yes
File Size Comparison Smaller than MP3 (in most cases)
Bookmarking Supported
Chapter Markers Supported
Metadata Support Extensive (Title, Author, Year, etc.)
Variable Bit Rate (VBR) Supported
Sample Rate Up to 48 kHz
Channels Up to Stereo
Encryption Optional (FairPlay DRM)
Interactive Menus Supported
Playback Speed Control Supported
Popular Platforms Support iOS, macOS, Windows, Android
Copy Protection Optional
Typical Use Case Long-duration audio content