One of the many functionalities of my phone which I do not use is the ability to record to a file. This file is saved in the phone and can then be played. For the first time I needed this functionality to here are the steps to get an usable mp3 file out of it.

  • download the file to the computer using the bluetooth method
  • install an amr decoder
apt-get install amrwb amrnb
  • decode the file to raw data

amrnb-decoder Recording.amr Recording.raw

  • play it
aplay -t raw -c 1 -r 8000 -f S16_LE Recording.raw

these parameters mean: 1 channel, rate 8000Hz, format 16 bit little endian. You can use them to import your raw file into audacity and convert it further to anything you like.