JUCE is an open-source cross-platform C++ application framework for desktop and mobile applications, including VST, VST3, AU, AUv3, RTAS and AAX audio plug-ins.

Enhanced version of Cockos' iPlug - A simple-to-use C++ framework for developing cross platform audio plugins and targeting multiple plugin APIs with the same code. VST / VST3 / Audiounit / RTAS / AAX (Native) formats supported. NOTE: THIS IS OBSOLETE, PLEASE SEE IPLUG2:

Open Source Audible Manager

C++ Audio Plug-in Framework for desktop, mobile and web [PRE-RELEASE]

Convert Audible's .aax filetype to MP3, FLAC, M4A, or OPUS

A user interface toolkit mainly for audio plug-ins

Make audio plug-ins with D

Convert Audible aax files to mp3 and m4a/m4b

Various resources related to developing plugins for audio production.

Fast Audible AAX to M4A converter

The Open Source Audible Converter

Audible audio book converter which actually works!

Audio plugin that lets you use MIDI to pitch-shift via delay to turn unpitched audio into melodies

Split AAX files from Audible into multiple MP3 files by chapter using ffmpeg.

Python script to convert AAX files to MP3

The User Group's RackAFX development on Windows. Courtesy of Tritone Systems, Inc.

Convert aax to ogg audio format

A public wiki containing lessons learned about audio plugin hosting and development.

AAX to MP3 converter and MP3 splitter by chapters

Audible Checksum Bruteforcer