Merge Audio Files into an Audiobook on Mac: Audiobook Binder Pro

One Book, One File

Audiobooks from Librivox come as 30 separate MP3s. Podcast back-catalogs live in folders of hundreds of files. Lecture recordings pile up as M4A files from Voice Memos. The common problem: you have many audio files that belong together, but your player treats them as separate tracks.

Audiobook Binder Pro merges them into a single M4B file with chapter markers for each original file. Your audiobook player sees one book with a clean chapter list, bookmarking, and cover art.

Supported Input Formats

Drop in files from any combination of these formats:

MP3 — the most common format for downloaded audiobooks and podcasts
M4A — Voice Memos recordings, Apple Music downloads, iTunes rips
WAV — uncompressed audio from DAWs and professional recording software
FLAC — lossless compressed audio, common for high-quality downloads
AIFF — Apple’s uncompressed format, used in GarageBand and Logic Pro
AAC — raw AAC streams from various sources

You can mix formats in the same project. The app handles all the transcoding to 128 kbps AAC in the final M4B.

How to Merge Audio into an Audiobook

Drop your files or folders

Drag audio files directly into Audiobook Binder Pro. You can also drop entire folders and the app will import all audio files inside, sorted by filename. This is especially useful for audiobooks split into numbered chapters like "Chapter 01.mp3", "Chapter 02.mp3", and so on.

Reorder and rename chapters

Each file becomes a chapter. Drag to reorder. Click a chapter name to rename it. Add cover art and set the book title, author, and narrator metadata. Everything you set here gets embedded in the final M4B.

Export your audiobook

Hit Export and choose where to save the M4B. The app encodes everything to 128 kbps AAC with embedded chapter markers. The output file works in Apple Books, Plex, Prologue, Audiobookshelf, and BookPlayer.

Use Cases

Podcast series as audiobooks

Finished a 40-episode podcast series? Merge the episodes into one M4B. Each episode becomes a chapter. Listen through the whole thing in your audiobook player with bookmarking and chapter skip.

Multi-part audiobook downloads

Free audiobooks from Librivox and Internet Archive often come as dozens of individual MP3 files. Merge them into a proper M4B so Apple Books or Prologue treats it as a single audiobook instead of 30 separate music tracks.

Lecture recordings

Record your university lectures with Voice Memos on iPhone. Each recording saves as M4A. At the end of the semester, merge them into one audiobook per course. Review for exams by jumping between chapter-labeled lectures.

Music albums as single files

Some people prefer having an entire album as one file with chapter markers per track. Useful for DJ mixes, live recordings, or concept albums you always listen to straight through.

FAQ

Is there a limit on how many files I can merge?

No limit on file count. The app handles hundreds of files in a single project. Practical limits depend on your disk space. Unlimited export length is coming in v1.6. A 40-hour audiobook at 128 kbps AAC is roughly 2.2 GB.

Do the files need to be in the same format?

No. You can mix MP3, M4A, WAV, FLAC, AIFF, and AAC files in the same project. Audiobook Binder Pro transcodes everything to AAC during export.

How does the app determine chapter order?

Files appear in the order you add them. If you drag a folder, files are sorted alphabetically by filename. You can reorder chapters manually by dragging them in the app's file list.

Does merging reduce audio quality?

All audio is re-encoded to 128 kbps AAC. For spoken word content, this is transparent quality, meaning you won't hear any difference from the original. If your source files were lower bitrate MP3s (like 64 kbps), the output quality matches the source since you can't gain quality by re-encoding.

Merge Audio Files into an Audiobook