HydrogenAudio

Lossy Audio Compression => Speech Codecs => Topic started by: encoder on 2014-01-21 06:25:32

Title: What can be known about Audible AA, AAX and AAX+ formats?
Post by: encoder on 2014-01-21 06:25:32
http://www.audible.com/audioformats (http://www.audible.com/audioformats)

The Internets talks about an AAX+ format, too. DRM notwithstanding, are they compatible with any standard or 3rd party player?
Title: What can be known about Audible AA, AAX and AAX+ formats?
Post by: AndyH-ha on 2014-01-21 07:59:33
Audible maintains a list, on their web site, of payers that will work with their downloads.
Title: What can be known about Audible AA, AAX and AAX+ formats?
Post by: AndyH-ha on 2014-01-21 08:01:56
There is a link to their list at the bottom of the page you mentioned.
Title: What can be known about Audible AA, AAX and AAX+ formats?
Post by: saratoga on 2014-01-21 08:25:58
wikipedia says .aa is usually mp3 or a speech codec.
Title: What can be known about Audible AA, AAX and AAX+ formats?
Post by: encoder on 2014-02-19 22:36:05
Thanks.
Title: What can be known about Audible AA, AAX and AAX+ formats?
Post by: jensend on 2014-02-20 05:18:25
The older .aa formats are apparently either ACELP or MP3, wrapped in Audible's proprietary DRM.

People say the 64kbps Audible Enhanced format is AAC-based; I can't find any reliable source for this but it obviously makes sense given that the format was introduced in 2009, is in a bitrate range where AAC has few competitors, and received device playback support fairly quickly.
Title: What can be known about Audible AA, AAX and AAX+ formats?
Post by: encoder on 2014-03-02 06:27:16
http://osherove.com/blog/2008/7/6/introduc...ooks-drm-f.html (http://osherove.com/blog/2008/7/6/introducing-audibler-download-your-audible-audio-books-drm-f.html)
Though this hole has obviously been fixed since then.

The main point: the DRM is added when the file is downloaded, on the client side.

So I toyed around downloading a few files then aborting the downloads in the middle, this is what I have found:

Enhanced AAX files: VLC player neatly showed the chapters, so they are highly likely M4B, aka. AAC book files. Just like files from Downpour/Blackstone. They started to play though no sounds was heard. I don't know much about AAC files, this is the way they are supposed to work?

Lower levels: Could not play them at all. Strange.
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