How AudioBo simplifies converting audio files into M4B audiobooks on macOS

I have been an audiobook fan for decades. I have had an Audible subscription since 2008 (before they were owned by Amazon), and I have listened to hundreds, if not thousands, of books during that time. A few years ago, I wrote about my process of taking cheap CD audiobooks from Amazon and combining them into M4B files to host on my Plex server. Once I discovered it was possible to put these files into Plex on my Mac Mini, it became my go-to audiobook setup for me. Paired with the Prologue app, it creates the ultimate listening experience that you own and control.

However, building those M4B files has always been a bit tedious without a dedicated app. MP3 files work great for music, but they fall apart as a collection of files for an audiobook. They lack true chapter support, bookmarks don’t work well, and the resume behavior can be troublesome depending on what app you use. Over the years, I have tried several tools to convert audio files into proper audiobooks, and while some are great, they all lack a critical feature: the ability to import audiobook metadata.

This is the problem that AudioBo aims to solve. It’s a native macOS app that completely streamlines the process of converting audio files into a proper M4B audiobook.

AudioBo handles all the technical decisions for you when building the books. You can drop in MP3, FLAC, or WAV files, and the app automatically aims for the best possible quality without taking up all of your free space. It writes proper M4B files (M4A with the B being for bookmarkable) with full support for QuickTime and Nero chapter formats. This means you get a clean and fully compliant container that works well in Apple Books, Prologue, or any app that can play M4B files.

As I mentioned at the beginning, the key feature for me was the metadata imports. With other solutions, I had to go find the right cover, add the author info, etc. AudioBo can import metadata from Audible, Apple Books, and Google Books to fill in cover art, book info, and chapter names with a single click. The batch chapter cleanup tool is also incredible. It lets you normalize titles, reorder tracks, and remove junk entries without having to touch every single track.

Another nice feature is avoiding unnecessary reencoding. If you only need to update the cover art or fix a typo in the title of an existing M4B file, AudioBo can preserve the original audio stream. There is no quality loss and no wasted encoding time. It just saves the updated metadata and updates the original file.

After testing AudioBo with several massive audiobook projects, I can confirm it delivers on its promises, and it’s my go-to app for building audiobooks on macOS.

AudioBo is available on the Mac App Store for a one-time purchase of $9.99, and there is a free demo on the developer’s website.