Convert M4B to M4A — Free Online Converter

M4B and M4A are both MPEG-4 Audio containers — the difference is that M4B signals audiobook content to players (enabling chapter navigation and bookmark resume), while M4A is treated as standard music. Converting M4B to M4A is essentially a container relabel: the AAC audio data, metadata, and even artwork are identical. The only functional change is that players no longer treat the file as an audiobook, losing chapter markers and the auto-bookmark feature.

Music apps and general-purpose players categorize M4A as music and M4B as audiobooks. Converting to M4A puts audiobook content in the music library. Podcast apps accept M4A but often reject M4B. Audio editors and production tools may not recognize M4B but handle M4A without issues. Some file-sharing platforms accept M4A but filter out M4B.