Today, an audio file was sent to me in an email. This audio was compressed and encoded using the aac codec for compression and wrapped in m4a. In order to use it, I had to convert this file to a wav format. Usually, I receive files in mp3, ogg, or flac file types, and use lame, oggdec, or flac to decode them back to wav. With m4a, I didn't quite know how to proceed.
In cases like this, I usually turn to sox
, which has been able to handle just about everything I throw at it. This time, it threw an error, telling me "sox formats: no handler for detected file type `audio/mp4'
". Although I knew this probably meant something like, "Hey, I know this file type, but I'm not compiled correctly to handle it! Help!", I didn't find an easy answer... So I started looking elsewhere.
I happened upon a wonderful plugin of audacious called "FileWriter" - which comes default in gentoo installations of audacious.
I right-clicked on the main window, went to Preferences ->Audio -> Current output plugin -> FileWriter Plugin
Then loaded the m4a file into audacious, and played it. About 3 seconds later, I had a nice new wav file contrived from the m4a file through audacious.
So, I thought I'd just let ya'll know how to convert from m4a to just about anything you need.