Bulk Convert M4B to WAV Online — Lossless Audio

M4B is Apple's audiobook format, essentially an M4A file with chapter markers and bookmark support. Introduced with iTunes in 2003, M4B uses AAC audio encoding in an MPEG-4 container—the same codec as M4A—but with additional metadata for chapter navigation and resume-position bookmarks. This makes M4B ideal for long-form audio content like audiobooks and podcasts. Files from Audible (after DRM removal), iTunes Store, and Librivox commonly use M4B format.

Learn more: M4B on Wikipedia

M4B supports sample rates up to 96 kHz and multi-channel audio, though most audiobooks use mono or stereo at 44.1 kHz for efficiency. The chapter markers embedded in M4B files enable navigation to specific sections—a feature lost when converting to formats like MP3 or WAV. For maximum compatibility with car stereos, older MP3 players, and non-Apple devices, converting M4B to MP3 is often necessary. For archival or editing, WAV extraction provides lossless quality.

WAV (Waveform Audio File Format) is an uncompressed audio format developed by Microsoft and IBM in 1991. It stores raw PCM (Pulse Code Modulation) audio data, preserving every sample from the original recording without any quality loss. WAV supports 16/24/32-bit depth, sample rates from 8 kHz to 192 kHz (commonly 44.1/48 kHz), and up to 65,535 channels. It's the standard working format for audio professionals in recording studios, broadcast facilities, and sound design workflows worldwide.

Learn more: WAV on Wikipedia

The main tradeoff is file size: a 3-minute stereo track at CD quality (44.1kHz, 16-bit) is approximately 30 MB. While this makes WAV impractical for streaming or portable devices, it remains essential for editing, archiving, and any workflow where audio quality is paramount. Converting to MP3 reduces file size by 90% or more while maintaining perceptually transparent quality for most listeners.