M4B Chapter Splitter

Split an unencrypted AAC-LC audiobook into neutral-name M4A or MP3 chapter files with measured timing.

Upload a chaptered audiobook

M4B audiobook

One signature-verified, unencrypted MP4-family audiobook up to 1 GB. This first release advertises fixture-proven AAC-LC audio.

Chapter audio format

M4A stream copy
Copies AAC without re-encoding. Cuts are packet-aligned, not claimed as sample-exact, and measured deltas are reported against the 0.25-second fixture-proven tolerance. MP3 compatibility
Re-encodes with the existing FFmpeg MP3 path at the bitrate you explicitly choose.

I have the right to process this audiobook and understand that DRM-protected files are rejected without decryption attempts.

Private, chapter-aware output

Reads stored chapters, primary audio properties, duration, codec, sample rate, channel layout, and cover-art presence.
Rejects missing, zero-length, overlapping, out-of-order, out-of-bounds, encrypted, malformed, and non-audio chapter sources.
Creates private CSV and JSON manifests with normalized timing and bounded warnings.
Uses neutral chapter-0001 names. Titles never enter URLs, logs, analytics, ZIP entry names, or download filenames.
Does not accept remote URLs, playlists, user timestamps, chapter edits, archives, or custom FFmpeg switches.

Results are private, served with no-store headers, retained only for the existing download window, and then cleaned up automatically.

Private chapter inventory

#	Chapter title	Start	End	Duration	Warnings

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M4B Chapter Splitter

Upload a chaptered audiobook

Private chapter inventory

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Upload a chaptered audiobook

Private chapter inventory

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