How to strip DRM from Audible audiobooks

I have a subscription with Audible which allows you to download an audiobook a month for keeps.

These books can be listened to on the Audible app but if you want to use another app then it needs to support Audible’s DRM system.

The particular app I wanted to use did not support DRM so I chose to remove the DRM from my purchases books.

To do this we’ll use a Python project audible-cli.

Install this using pip:

$ pip install audible-cli

Once installed we can run audible quickstart - this will start a wizard that creates a configuration file.

Next we can run audible library list to list our Audible library and choose the audiobook we want to download.

$ audible library list
...
B015ELUYL4: Kurt Vonnegut: Slaughterhouse-Five

We can then download the aax file using the download subcommand:

$ audible download --aax --asin B015ELUYL4

Once downloaded we need the activate bytes to decode the DRM:

$ audible activation-bytes
7224181c

With these bytes we can convert the aax to mp3 without DRM:

$ ffmpeg -activation_bytes 7224181c -i Slaughterhouse-Five-LC_64_22050_stereo.aax Slaughterhouse-Five-LC_64_22050_stereo.mp3

Alternatively AAXtoMP3 does a great job of converting the aax to a variety of codecs (AAC command shown below) whilst keeping metadata and cover-art intact.

$ bash AAXtoMP3 -a -A 7224181c Slaughterhouse-Five-LC_64_22050_stereo.aax