#!/bin/sh
# reference: https://superuser.com/questions/704493/ffmpeg-convert-m4a-files-to-mp3-without-significant-loss-of-information-quali/704535#704535

logfile="/mnt/bgstack15/log/m4a-to-mp3.$( date -u "+%FT%H%M%SZ" ).log"

func() {
for word in "$@" ;
do
   echo "Entering item ${word}";
   outdir="${word}/mp3" ; mkdir "${outdir}" || exit 1 ;
   find "${word}" -type f \( -regex '.*M4A' -o -regex '.*m4a' \) | while IFS='\0' read infile ;
   do
      test -f "${infile}" && echo "Found file: \"${infile}\"" || echo "INVALID! ${infile}"
      outfile="$( echo "${infile}" | sed -r -e "s/\.m4a/\.mp3/i" )"
      echo  ffmpeg -i \"${infile}\" -codec:v copy -codec:a libmp3lame -q:a 2 \"${outfile}\"
      yes | ffmpeg -i "${infile}" -codec:v copy -codec:a libmp3lame -q:a 2 -y "${outfile}" ; test -n "${outdir}" && /bin/mv -f "${outfile}" "${outdir}/" ;
      sleep 2 ;
   done
done
}


time func "$@" | tee -a "${logfile}"