Audiobook Maker

What it's for

Turn a set of recorded chapters into one audiobook file. An M4B is AAC sound (the format of an .m4a) with a chapter list, so a listener can skip from chapter to chapter, and an audiobook player remembers where they stopped. This joins the chapters in the order you choose, marks where each starts, and adds the book’s title, author, narrator and cover.

For example, when you’ve recorded a short book or a course one chapter at a time, choose all the chapter files here and save a single .m4b for Apple Books or another audiobook app.

How to use it

Choose the chapter files (MP3, WAV, M4A, FLAC or Ogg, as far as this browser plays them), several at once, or drop them on the Chapter files box. They’re sorted by file name as they’re added, so 2 comes before 10. Each chapter’s title starts as the file’s own title tag, or its name without the extension and a leading number (03 - The Storm.mp3 becomes The Storm); change any title, and use the arrows to reorder.

Fill in the book’s details, and choose a JPEG or PNG for the cover if you like (drop it on its own box). Sound and Quality are remembered in this browser: mono at 64 or 96 kbit/s suits speech; choose stereo for music. Make the audiobook re-encodes every chapter, one after another, and saves <title>.m4b.

Example

In the Tone Generator, save a sine wave at 440 Hz for 3 seconds and another at 660 Hz for 2 seconds. Choose both files here, type Tones as the book title, and Make the audiobook.

The chapters are tone-440hz and tone-660hz, and it saves Tones.m4b: “2 chapters, 0:05 long”. Open it in the Audiobook Splitter or Audio Tags to see the second chapter starting at 0:03.

Good to know

Making AAC needs a browser that can encode it (Chrome, Edge or Safari; not Firefox). The sound is re-encoded, so start from the best copies you have, not MP3s made from MP3s. Every chapter is resampled to 44.1 kHz, and a chapter is held in memory while it’s encoded, so very long chapters (several hours each) may be too big for the browser.

The chapter list is written both in Apple’s form and in the form most other players read (Nero’s), but players differ: check the result in the app you’ll use. The narrator is stored as the composer, where most apps show it. It doesn’t check loudness or levels: use the Loudness Meter on each chapter first.