m4Bookmaker

m4Bookmaker is a Mac & Windows app for building properly-chaptered M4B audiobooks from folders of MP3s — with a visual chapter editor, automatic audio repair, and no ffmpeg setup required. 

Windows 10, macOS 13 (Ventura) or later

https://m4bookmaker.sageframe.net/

v1.1.1

What's new in 1.1.0/1.1.1:

• Fixed a crash on Apple Silicon Macs where the app quit immediately on launch without opening a window, due to a dark mode emoji drawing error.
• Narrator edits to an existing M4B now stick.
• Removing a chapter marker in Edit mode no longer shifts every later chapter out of place.
• Chapter time edits now apply when you press Convert or Add to Queue.
• A failed or cancelled conversion can no longer overwrite a finished audiobook.
• Quitting mid-conversion now cancels cleanly instead of leaving a half-written file behind.
• Special characters in titles and filenames no longer break chapters or fail a conversion at the end — "Dune: Messiah" saves correctly, and "Part #2.mp3" keeps its full chapter title.
• Chapter marks stay accurate when damaged files are repaired.

What's new in 1.0.4/5:

• Intel Mac Support — macOS 13 (Ventura) or later
• Fixed a crash on Intel Macs where the app would refuse to open with "application is not supported on this Mac." The macOS build now runs on both Intel and Apple Silicon.
• Also fixed a Finder display bug where output files were incorrectly labeled "Protected mpeg 4 audiobook."
• Chapter names now use the track's embedded title tag when available, rather than the filename.

What's new in 1.0.3:

• Fixed a bug where opening an M4B to edit chapters would strip the book's Title, Author, Narrator, and Genre. All metadata fields now save correctly.

What's new in 1.0.2:

• Edit mode — Open any existing M4B file to review and update its chapter list without re-encoding. Cover art, metadata, and duration are pre-filled automatically.
• Add Chapter — Insert a new chapter at the current playhead position in Edit mode.
• Millisecond-precision timestamps — Chapter times are displayed and editable to the millisecond.
• Direct timestamp editing — Click any timestamp cell to edit it in place.
• macOS fix — Resolved a hang that could occur when loading M4B files on macOS.