Stripping Audible DRM ⚓

Self-Guide for stripping the Audible DRM, in similar vein as my Kindle Self-Guide.

1. Download the aax file from Audible website.
2. Run the inAudible-NG Rainbrow crack table against the AAX file.

Easiest way is via docker/podman:

cd ~/Music/Audiobooks
podman run -v $(pwd):/data ryanfb/inaudible@sha256:b66738d235be1007797e3a0a0ead115fa227e81e2ab5b7befb97d43f7712fac5
for i in "*.m4a"; do fix-audible-m4a "$i";done

The cool part about this is that the entire activation is done offline, and runs a Rainbow Table attack against the Audible DRM. To make the process faster in the future, you can save your “activation bytes” (8 hex characters) and directly use them with ffmpeg to decode instead:

ffmpeg -loglevel panic -y -activation_bytes ${AUDIBLE_ACTIVATION_BYTES} -i "$aax_file" -c:a copy -vn "$m4a_file"

A small percentage of Audible AAX files have a incorrect bit set in the “Audio Object Type Specific Config” in the ESDS atom in an M4A file, which leads to them not playing in Firefox/Android and some other players. To fix this, I have a fix-audible-m4a script called above.

References

• https://github.com/ryanfb/docker_inaudible_rainbowcrack
• https://github.com/inAudible-NG/tables
• https://rentry.co/n4ost

Published on April 14, 2019