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Krumpet Pirate e66c51dbfa Merge pull request #211 from utf8please/patch-1 10 months ago
.gitignore bcfdf0ac06 ignore jpg (cover) and json (chapters) files 2 years ago
AAXtoMP3 e66c51dbfa Merge pull request #211 from utf8please/patch-1 10 months ago
LICENSE 9d28be4f06 Added support for chapters as well as convert to bash script 7 years ago 8fc5e360d3 fix: typo '--aac' not '-aac' 1 year ago
_config.yml ee0c971544 Set theme jekyll-theme-slate 5 years ago
interactiveAAXtoMP3 051f37b3ff Made savefile invisible 2 years ago


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

Audible uses the AAX 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 3.2.57 or later tested
  • ffmpeg version 2.8.3 or later (4.4 or later if the input file is .aaxc)
  • libmp3lame - (typically 'lame' in your system's package manager)
  • GNU grep - macOS or BSD users may need to install through package manager
  • GNU sed - see above
  • GNU find - see above
  • jq - only if --use-audible-cli-data is set or if converting an .aaxc file
  • mp4art used to add cover art to m4a and m4b files. Optional
  • mediainfo used to add additional media tags like narrator. Optional


bash AAXtoMP3 [-f|--flac] [-o|--opus] [-a|--aac] [-s|--single] [--level <COMPRESSIONLEVEL>] [-c|--chaptered] [-e:mp3] [-e:m4a] [-e:m4b] [-A|--authcode <AUTHCODE>] [-n|--no-clobber] [-t|--target_dir <PATH>] [-C|--complete_dir <PATH>] [-V|--validate] [--use-audible-cli-data]] [-d|--debug] [-h|--help] [--continue <CHAPTERNUMBER>] <AAX/AAXC INPUT_FILES>...

or if you want to get guided through the options

bash interactiveAAXtoMP3 [-a|--advanced] [-h|--help]
  • <AAX INPUT_FILES>... are considered input file(s), useful for batching!

Options for AAXtoMP3

  • -f or --flac Flac Encoding and as default 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. Not needed if the source file is .aaxc.
  • -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 --flac options.
  • --continue <CHAPTERNUMBER> If the splitting into chapters gets interrupted (e.g. by a weak battery on your laptop) you can go on where the process got interrupted. Just delete the last chapter (which was incompletely generated) and redo the task with "--continue <CHAPTERNUMBER>" where CHAPTERNUMBER is the chapter that got interrupted.
  • --level <COMPRESSIONLEVEL> Set compression level. May be given for mp3, flac and opus.
  • --keep-author <FIELD> If a book has multiple authors and you don't want all of them in the metadata, with this flag you can specify a specific author (1 is the first, 2 is the second...) to keep while discarding the others.
  • --author <AUTHOR> Manually set the author metadata field, useful if you have multiple books of the same author but the name reported is different (eg. spacing, accents..). Has precedence over --keep-author.
  • -l or --loglevel <LOGLEVEL> Set loglevel: 0 = progress only, 1 (default) = more information, output of chapter splitting progress is limitted to a progressbar, 2 = more information, especially on chapter splitting, 3 = debug mode
  • --dir-naming-scheme <STRING> or -D Use a custom directory naming scheme, with variables. See below for more info.
  • --file-naming-scheme <STRING> or -F Use a custom file naming scheme, with variables. See below for more info.
  • --chapter-naming-scheme <STRING> Use a custom chapter naming scheme, with variables. See below for more info.
  • --use-audible-cli-data Use additional data got with mkb79/audible-cli. See below for more info. Needed for the files in the aaxc format.
  • --audible-cli-library-file or -L Path of the library-file, generated by mkb79/audible-cli (audible library export -o ./library.tsv). Only available if --use-audible-cli-data is set. This file is required to parse additional metadata such as $series or $series_sequence.
  • --ffmpeg-path Set the ffmpeg/ffprobe binaries folder. Both of them must be executable and in the same folder.
  • --ffmpeg-name Set a custom name for the ffmpeg binary. Must be executable and in path, or in custom path specified by --ffmpeg-path.
  • --ffprobe-name Set a custom name for the ffprobe binary. Must be executable and in path, or in custom path specified by --ffmpeg-path.

Options for interactiveAAXtoMP3

  • -a or --advanced Get more options to choose. Not used right now.
  • -h or --help Get a help prompt. This script presents you the options you chose last time as default. When you get asked for the aax-file you may just drag'n'drop it to the terminal.


Your Audible auth code (it won't correctly decode otherwise) (not required to decode the aaxc format).

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 or like audible-cli.

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 if converting aax files. 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.
  • --level has to be in range 0-9, where 9 is fastest and 0 is highest quality. Please note: The quality can never become higher than the qualitiy of the original aax file!

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.
  • --level has to be in range 0-10, where 0 is fastest and 10 is highest quality. Please note: The quality can never become higher than the qualitiy of the original aax file!

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
  • This will only produce 1 audio file as output. If you want a flac file per chapter do use -c or --chaptered.
  • --level has to be in range 0-12, where 0 is fastest and 12 is highest compression. Since flac is lossless, the quality always remains the same.

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.

Custom naming scheme

The following flags can modify the default naming scheme:

  • --dir-naming-scheme or -D
  • --file-naming-scheme or -F
  • --chapter-naming-scheme

Each flag takes a string as argument. If the string contains a variable defined in the script (eg. artist, title, chapter, narrator...), the corresponding value is used. The default options correspond to the following flags:

  • --dir-naming-scheme '$genre/$artist/$title'
  • --file-naming-scheme '$title'
  • --chapter-naming-scheme '$title-$(printf %0${#chaptercount}d $chapternum) $chapter'

Additional notes:

  • If a command substitution is present in the passed string, (for example $(printf %0${#chaptercount}d $chapternum), used to pad with zeros the chapter number), the commands are executed. So you can use --dir-naming-scheme '$(date +%Y)/$artist', but using --file-naming-scheme '$(rm -rf /)' is a really bad idea. Be careful.
  • You can use basic text, like --dir-naming-scheme 'Converted/$title'
  • You can also use shell variables as long as you escape them properly: CustomGenre=Horror ./AAXtoMP3 --dir-naming-scheme "$CustomGenre/\$artist/\$title" *.aax
  • If you want shorter chapter names, use --chapter-naming-scheme '$(printf %0${#chaptercount}d $chapternum) $chapter': only chapter number and chapter name
  • If you want to append the narrator name to the title, use --dir-naming-scheme '$genre/$artist/$title-$narrator' --file-naming-scheme '$title-$narrator'
  • If you don't want to have the books separated by author, use --dir-naming-scheme '$genre/$title'
  • To be able to use $series or $series_sequence in the schemes the following is required:
    • --use-audible-cli-data is set
    • you have pre-generated the library-file via audible library export -o ./library.tsv
    • you have set the path to the generated library-file via --audible-cli-library-file ./library.tsv

Installing Dependencies.

In general, take a look at


Ubuntu, Linux Mint, Debian

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

In Debian-based system's repositories the ffmpeg version is often outdated. If you want to convert .aaxc files, you need at least ffmpeg 4.4. So if your installed version needs to be updated, you can either install a custom repository that has the newer version, compile ffmpeg from source or download pre-compiled binaries. You can then tell AAXtoMP3 to use the compiled binaries with the --ffmpeg-path flag. You need to specify the folder where the ffmpeg and ffprobe binaries are. Make sure they are both executable.

If you have snapd installed, you can also install a recent version of 4.4 from the edge channel:

snap install ffmpeg --edge

In this case you will need to confiure a custom path and binary name for ffprobe, --ffmpeg-path /snap/bin/ --ffprobe-name ffmpeg.ffprobe.


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
brew install findutils


Note: This is an optional dependency, required for adding cover art to m4a and b4b files only.

Ubuntu, Linux Mint, Debian

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

On Debian and Ubuntu the mp4v2-utils package has been deprecated and removed, as the upsteam project is no longer maintained. The package was removed in Debian Buster, and Ubuntu Focal [ 20.04 ].

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


Note: This is an optional dependency.

Ubuntu, Linux Mint, Debian

sudo apt-get update
sudo apt-get install mediainfo

CentOS, RHEL & Fedora

yum install mediainfo


brew install mediainfo

AAXC files

The AAXC format is a new Audible encryption format, meant to replace the old AAX. The encryption has been updated, and now to decrypt the file the authcode is not sufficient, we need two "keys" which are unique for each audiobook. Since getting those keys is not simple, for now the method used to get them is handled by the package audible-cli, that stores them in a file when downloading the aaxc file. This means that in order to decrypt the aaxc files, they must be downloaded with audible-cli. Note that you need at least ffmpeg 4.4.

Audible-cli integration

Some information are not present in the AAX file. For example the chapters's title, additional chapters division (Opening and End credits, Copyright and more). Those information are avaiable via a non-public audible API. This repo provides a python API wrapper, and the audible-cli packege makes easy to get more info. In particular the flags --cover --cover-size 1215 --chapter downloads a better-quality cover (.jpg) and detailed chapter infos (.json). More info are avaiable on the package page.

Some books might not be avaiable in the old aax format, but only in the newer aaxc format. In that case, you can use audible-cli to download them. For example, to download all the books in your library in the newer aaxc format, as well as chapters's title and an HQ cover: audible download --all --aaxc --cover --cover-size 1215 --chapter.

To make AAXtoMP3 use the additional data, specify the --use-audible-cli-data flag: it expects the cover and the chapter files (and the voucher, if converting an aaxc file) to be in the same location of the AAX file. The naming of these files must be the one set by audible-cli. When converting aaxc files, the variable is automatically set, so be sure to follow the instructions in this paragraph.

For more information on how to use the audible-cli package, check out the git page audible-cli.

Please note that right now audible-cli is in dev stage, so keep in mind that the naming scheme of the additional files, the flags syntax and other things can change without warning.

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.