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Is there a Windows program that can convert audio books in .M4B format to Audible book format?

Why?... I want to play the book on a Garmin Nuvi.

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Notes from the Wikipedia pages -- MP4 versus M4A file extensions

Audio-only MPEG-4 files generally have a .m4a extension. This is especially true of non-protected content.

MPEG-4 files with audio streams encrypted by FairPlay Digital Rights Management as sold through the iTunes Store use the .m4p extension. iTunes Plus tracks are unencrypted and use .m4a accordingly.

Audio book and podcast files, which also contain metadata including chapter markers, images, and hyperlinks, can use the extension .m4a, but more commonly use the .m4b extension. An .m4a audio file cannot "bookmark" (remember the last listening spot), whereas .m4b extension files can.

I am not sure, but this seems to imply that the m4b files are not encrypted...
You could convert them to MP3 files -- probably with something like the MediaCoder Audio edition.
You will loose the special features of the M4B format.

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Audible use a proprietary format for their Audible Book files (.aa) and don't licence any software to convert to this format.
The only real option if you want to listen on a Garmin is to convert the .m4b files to .mp3 (e.g. using Format Factory - you may need to rename the files from .m4b to .m4a) - though you'd lose the bookmarking feature.

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I'm assuming, if you have an M4B, that you bought it off the iTunes Store. Audible provides all the audiobooks for the iTunes Store at the current time.

You have two options here:

  • Break the digital rights management (DRM) software that is built into the M4P/M4B format. This is very illegal in the US, and probably why you won't be able to find an app to do it easily.
  • Go to Audible and explain how you bought their product from iTunes and want to use it on a different platform.

The ugly side of DRM is that it prevents the format-shifting you want to do and would normally be legal (even in the US). Think of your situation as akin to trying to convert a DVD to play on an iPod/iPhone: it is technically feasible, but the restrictions of breaking DRM make it illegal, and instead require you to buy it again in a different format.

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I have several 'old' books on CD, and ripped them to MP3. I also found this item to convert mp3->m4b… – WireGuy Aug 4 '09 at 20:40

The simplest legal way to do this is to use iTunes to convert the audio cds and then import them again using itunes (not all books can be exported this way). This is time consuming and annoying but perfectly legal. This step can be bypassed using a virtual DVD/CD burner with MP3 capabilites, there are many which cost money that will do directly what you want. It a trade off of time verses cost of a program.

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