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KrumpetPirate committed 2ef05cd Jul 14, 2020
Remove chapter metadata in "chaptered mode"


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The purpose of this software is to convert AAX files to common MP3, M4A, M4B, flac and ogg formats through a basic bash script frontend to FFMPEG.

Audible uses this file format to maintain DRM restrictions on their audio books and if you download your book through your library it will be stored in this format.

The purpose of this software is not to circumvent the DRM restrictions for audio books that you do not own in that you do not have them on your personal Audible account. The purpose of this software is to create a method for you to download and store your books just in case Audible fails for some reason.


  • bash 4.3.42 or later tested
  • ffmpeg version 2.8.3 or later
  • libmp3lame (came from lame package on Arch, not sure where else this is stored)
  • grep Some OS distributions do not have it installed.
  • sed Some OS versions will need to install gnu sed.
  • mp4art used to add cover art to m4a and m4b files. Optional


Thanks to thibaudcolas, this script has been tested on OSX 10.11.6 El Capitan. YMMV, but it should work for conversions in OSX. It is recommended that you install GNU grep using 'brew install grep' for chapter padding to work.


Thanks to kbabioch, this script has also been packaged in the AUR. Note that you will still need to extract your activation bytes before use.


bash AAXtoMP3 [-f|--flac] [-o|--opus] [-a|-aac] [-s|--single] [-c|--chaptered] [-e:mp3] [-e:m4a] [-e:m4b] [-A|--authcode <AUTHCODE>] [-n|--no-clobber] [-t|--target_dir <PATH>] [-C|--complete_dir <PATH>] [-V|--validate] [-d|--debug] [-h|--help] <AAX INPUT_FILES>...
  • <AAX INPUT_FILES>... are considered input file(s), useful for batching!


  • -f or --flac Flac Encoding and Produces a single file.
  • -o or --opus Ogg/Opus Encoding defaults to multiple file output by chapter. The extension is .ogg
  • -a or --aac AAC Encoding and produce a m4a single files output.
  • -A or --authcode <AUTHCODE> for this execution of the command use the provided <AUTHCODE> to decode the AAX file.
  • -n or --no-clobber If set and the target directory already exists, AAXtoMP3 will exit without overwriting anything.
  • -t or --target_dir <PATH> change the default output location to the named <PATH>. Note the default location is ./Audiobook of the directory to which each AAX file resides.
  • -C or --complete_dir <PATH> a directory to place aax files after they have been decoded successfully. Note make a back up of your aax files prior to using this option. Just in case something goes wrong.
  • -V or --validate Perform 2 validation tests on the supplied aax files. This is more extensive than the normal validation as we attempt to transcode the aax file to a null file. This can take a long period of time. However it is useful when inspecting a large set of aax files prior to transcoding. As download errors are common with Audible servers.
  • -e:mp3 Identical to defaults.
  • -e:m4a Create a m4a audio file. This is identical to --aac
  • -e:m4b Create a m4b audio file. This is the book version of the m4a format.
  • -s or --single Output a single file for the entire book. If you only want a single ogg file for instance.
  • -c or --chaptered Output a single file per chapter. The --chaptered will only work if it follows the --aac -e:m4a -e:m4b options.


Your Audible auth code (it won't correctly decode otherwise) (required).

Determining your own AUTHCODE

You will need your authentication code that comes from Audible's servers. This will be used by ffmpeg to perform the initial audio convert. You can obtain this string from a tool like audible-activator.

Specifying the AUTHCODE.

In order of precidence.

  1. --authcode [AUTHCODE] The command line option. With the highest precedence.
  2. .authcode If this file is placed in the current working directory and contains only the authcode it is used if the above is not.
  3. ~/.authcode a global config file for all the tools. And is used as the default if none of the above are specified. Note: At least one of the above must be exist. The code must also match the encoding for the user that owns the AAX file(s). If the authcode does not match the AAX file no transcoding will occur.

MP3 Encoding

  • This is the default encoding
  • Produces 1 or more mp3 files for the AAX title.
  • The default mode is chaptered
  • If you want a mp3 file per chapter do not use the -single option.
  • A m3u playlist file will also be created in this instance in the case of default chaptered output.

Ogg/Opus Encoding

  • Can be done by using the -o or --opus command line switches
  • The default mode is chaptered
  • Opus coded files are stored in the ogg container format for better compatibility.

AAC Encoding

  • Can be done by using the -a or --aac command line switches
  • The default mode is single
  • Designed to be the successor of the MP3 format
  • Generally achieves better sound quality than MP3 at the same bit rate.
  • This will only produce 1 audio file as output.

FLAC Encoding

  • Can be done by using the -f or --flac command line switches
  • The default mode is single
  • FLAC is an open format with royalty-free licensing
  • Note: There is an bug with the ffmpeg software that prevents the splitting of flac files. Chaptered output of flac files will fail.

M4A and M4B Containers

  • These containers were created by Apple Inc. They were meant to be the successor to mp3.
  • M4A is a container that is meant to hold music and is typically of a higher bitrate.
  • M4B is a container that is meant to hold audiobooks and is typically has bitrates of 64k and 32k.
  • Both formats are chaptered
  • Both support coverart internal
  • The default mode is single

Validating AAX files

  • The --validate option will result in only a validation pass over the supplied aax file(s). No transcoding will occur. This is useful when you wish to ensure you have a proper download of your personal Audible audio books. With this option all supplied books are validated.
  • If you do NOT supply the --validate option all audio books are still validated when they are processed. However if there is an invalid audio book in the supplied list of books the processing will stop at that point.
  • A third test is performed on the file where the entire file is inspected to see if it is valid. This is a lengthy process. However it will not break the script when an invalid file is found.
  • The 3 test current are:
    1. aax present
    2. meta data header in file is valid and complete
    3. entire file is valid and complete. only executed with the --validate option.


  • Default out put directory is the base directory of each file listed. Plus the genre, Artist and Title of the Audio Book.
  • The default codec is mp3
  • The default output is by chapter.

Installing Dependencies.


Ubuntu, Linux Mint, Debian

sudo apt-get update
sudo apt-get install ffmpeg libav-tools x264 x265 bc


Fedora users need to enable the rpm fusion repository to install ffmpeg. Version 22 and upwards are currently supported. The following command works independent of your current version:

sudo dnf install$(rpm -E %fedora).noarch.rpm$(rpm -E %fedora).noarch.rpm

Afterwards use the package manager to install ffmpeg:

sudo dnf install ffmpeg

RHEL or compatible like CentOS

RHEL version 6 and 7 are currently able to use rpm fusion. In order to use rpm fusion you have to enable EPEL, see

Add the rpm fusion repositories in version 6

sudo yum localinstall --nogpgcheck

or version 7:

sudo yum localinstall --nogpgcheck

then install ffmpeg:

sudo yum install ffmpeg


brew install ffmpeg
brew install gnu-sed
brew install grep


Note: This is an optional dependency.

Ubuntu, Linux Mint, Debian

sudo apt-get update
sudo apt-get install mp4v2-utils

CentOS, RHEL & Fedora

# CentOS/RHEL and Fedora users make sure that you have enabled atrpms repository in system. Let’s begin installing FFmpeg as per your operating system.
yum install mp4v2-utils


brew install mp4v2

Anti-Piracy Notice

Note that this project does NOT ‘crack’ the DRM. It simply allows the user to use their own encryption key (fetched from Audible servers) to decrypt the audiobook in the same manner that the official audiobook playing software does.

Please only use this application for gaining full access to your own audiobooks for archiving/conversion/convenience. DeDRMed audiobooks should not be uploaded to open servers, torrents, or other methods of mass distribution. No help will be given to people doing such things. Authors, retailers, and publishers all need to make a living, so that they can continue to produce audiobooks for us to hear, and enjoy. Don’t be a parasite.

This blurb is borrowed from the page.


Changed the license to the WTFPL, do whatever you like with this script. Ultimately it's just a front-end for ffmpeg after all.

Need Help?

I'll help out if you are having issues, just submit and issue and I'll get back to you when I can.

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