If you have a large collection of files in a certain format and need to convert it to another, it can be quite tricky to do so and retain every tag information and all (i didn’t find any tool that would allow me to do that, even the excellent xACT doesn’t)

So …

you will need to have ffmpeg installed. I just used sudo port install ffmpeg on my mac.

First you need to write a little shell script. I’ve called it toflac.sh. This script will perform the conversion :

1
2
3

#!/bin/sh

ffmpeg -i "$1" -f flac "${1%.m4a}.flac"

(change the extensions appropriately to fit your needs)

then call it using the following command line:

‘’‘shell find . -name *.m4a -print0 | xargs -0 -P 4 -n 1 ./toflac.sh ` ’‘’

this one runs 4 parallel ffmpeg processes to convert your files. Quite handy.