How to listen to Audible files?

Update August 2020:

They removed .aa files from the website, you can now only download .aax. Support confirmed that .aa files are no longer available for download and recommends to install their tracking app instead.

The .aax files can also be converted with ffmpeg, but you need your unique "activation bytes":

ffmpeg -activation_bytes AABBCCDD -i YOURBOOK.aax -codec copy OUTPUT.aac

The activation bytes can be found by a few methods:

• Temporarily install the app and grab the /data/data/com.audible.application/files/AudibleActivation.sys file. Because Android hates it when people can access their own files, you probably need root to do this. Then use either this script, or just grab the first four bytes as hexadecimals in little-endian (backwards notation; reverse them).
• Using the Audible Activator. This didn't work for me, perhaps because I am using Audible Germany, but it has been a while and it seems to work for other people.

Original method for .aa files:

In your library, near the right top corner, you can select "Normal Quality" (formerly called "Format 4"). The download links will change to .aa files. From what I understand, they're a weird kind of mp3 which is easily converted using ffmpeg. This option (to pick Format 4) is only available if your browser's user agent looks like a Linux system.

To convert .aa files to MP3, the simplest way (easiest to remember) is this:

ffmpeg -i downloaded_file.aa output.mp3

The -i option just specifies the input file. The output file needs no option. This will, however, will re-encode the file (losing a little bit of quality, and it's slow).

It is better (10× faster) to use the 'stream copy' feature:

ffmpeg -i downloaded_file.aa -codec copy output.mp3

Please do not use this for piracy. If this is used for illegal copying, Audible will just disable downloading these files and make life a bitch for everyone (except for the pirates: they will always find a way, e.g. loopback recording, which is annoying, but it works). I am posting this to make it possible to use free software to read your books, and to be able to use apps like Smart AudioBook Player (which has more features and is not locked to a single vendor).

Warning to pirates: they leave markers in files so it can be traced back if someone uploads it. These markers are impossible to hear. Of course they're not telling us what they do exactly, but I've read scientific papers where they managed to find the markers very reliably even after they mangled the files into different formats, played at variable 0.9-1.1x speed, etc. See these Google Scholar results as example.

If the internet sources I found are correct, Audible uses a DRM solution known as "Apple FairPlay" (which is everything but fair play, of course...).

There seems to be no way to listen to Audible .aa files in Ubuntu directly, but some other disappointed customers have found solutions to convert them to something usable:

• Use the Windows software in Virtualbox and rip the audio on the host
• Use some audio editor tools on Windows with an old version of the Audible software (somebody on another forum used another sound editor to do the same)

Note: Audible says it actively works on linux support, but from what I read on-line they have been saying that since forever. Maybe you need to remind them about it... ;)

Note: this solution has been originally tested for Ubuntu 14.04 LTS with Firefox 42.0. I tested it again with the new Firefox Quantum 57.0.4 64 bit (still Ubuntu 14.04 LTS) and it still works. Other users are reporting that the cloud player is not working on later versions of Ubuntu with different browsers.

Audible made available a cloud player allowing subscribers to listen to their audio-books library from a web browser.

I tested it on Ubuntu 14.04 LTS with Firefox 42.0 and it worked nicely. In order to open the cloud player, from the homepage, just go to your Library. There you will find the list of your books. Under the cover of each book you will find the Play button, just click on it.

Note: as cloud player, you cannot use it when offline. Hence, not an ideal solution but it is an improvement.

You can use mplayer in terminal. I'm personally using it in Arch but it will work on ubuntu also.

mplayer /path/to/audiblefile.aa

If you do not have have it installed. Install it using

sudo apt update && sudo apt install mplayer

or follow the instructions on their website to compile and run it from source.

Alternatively for a GUI, you can just open the file in VLC Player

sudo apt update && sudo apt install vlc

I use OpenAudible. It is a simple, and easy-to-use software which you can use to convert audible files to .mp3.