Bulk Convert M4B to M4A Online — Strip Chapter Markers

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.

M4A (MPEG-4 Audio) is Apple's container format for AAC-encoded audio, introduced with iTunes in 2001. AAC itself was standardized by MPEG in 1997 (MPEG-2) and enhanced in 1999 (MPEG-4), achieving compression ratios of 8:1 to 12:1. M4A has become synonymous with Apple's ecosystem—it's the default for iTunes purchases, Apple Music downloads, and iPhone voice memos. At equivalent bitrates, AAC delivers better quality than MP3, with 256 kbps M4A typically matching 320 kbps MP3.

Learn more: M4A on Wikipedia

M4A supports sample rates up to 96 kHz and up to 48 audio channels, including surround sound configurations. The main limitation is compatibility—while modern devices handle M4A well, older hardware and some software (particularly on Windows and Linux) may not support it natively. For universal playback, MP3 remains the safer choice. M4A excels for Apple-centric workflows: syncing to iPhone, organizing in iTunes/Music app, or archiving Apple Music downloads.