• Free and Open Source software.
• Converts Audible proprietary .aax files to plain .mp3 or .m4a/.m4b.
• Also offers basic support for older .aa files.
• Windows application, with all the classic features of the Windows eco-system.
• Requires activated Audible Manager/App or personal activation code.
• Processing Modes:
  • One output file per input file.
  • Multiple output files per input file, divided by chapter.
  • Multiple output files per input file, divided by chapter and further split into shorter tracks of roughly equal length.
  • Multiple output files per input file, split into shorter tracks of roughly equal length, ignoring chapters.
• Creates additional playlist if more than one output file is created per book.
• Handles books with multiple parts.
• Manages and preserves all meta-tag information.
• Supports named chapters, for .aax files downloaded with the Audible App.
• Can adjust inaccurate chapter marks.
• Allows customization of output naming: files, folders and tags.
• Delegates all audio processing to powerful FFmpeg, including DRM handling.
• High performance: Utilizes all available processor cores to run conversion work in parallel.
• Optionally copies original .aax file to a new location after the conversion, with a customizable name.
• Automatically launches default media player after conversion has completed.
• Log facility, optional, to record program activity, activated with program argument.
• Online update function: Will automatically scan the website for a new version, download and install it.
• Technical:
  • .Net Framework application, written in C# with Windows Forms, the Task Parallel Library and other goodies from language and framework.
  • Incorporating a number of snippets from the Open Source community.

https://github.com/audiamus/AaxAudioConverter