How do I convert an M4A file to an MP3 or WMA file programmatically? [closed]

Answer 1

This is simple if you know the right tools:

ffmpeg -i infile.m4a tmp.wav
lame tmp.wav outfile.mp3

Here a batch version (sorry Linux/Mac only):

#!/bin/bash

n=0
maxjobs=3

for i in *.m4a ; do
    ffmpeg -i "$i" "$TMP/${i%m4a}wav"
    (lame "$TMP/${i%m4a}wav" "${i%m4a}mp3" ; rm "$TMP/${i%m4a}wav") &

    # limit jobs
    if (( $(($((++n)) % $maxjobs)) == 0 )) ; then
        wait
    fi

done