aac2mp3

Ok here is a little script that does all that in one step. THX to Nico for a good working one, and BIG thanks to Reto L. for a new improved version that comes with switches for program paths, bitrate and more useful options! see 'aac2mp3 -h' for a help text

#format bash
#!/bin/bash
#
# $Id: aac2mp3,v 1.2 2005/08/22 15:32:34 rali Exp $
#

#
# Convert one or more AAC/M4A files to MP3.  Based on a script example
# I found at: http://gimpel.gi.funpic.de/Howtos/convert_aac/index.html
#

ME=`basename ${0}`

AAC2WAV="/usr/bin/mplayer"
WAV2MP3="/usr/bin/lame"

EXT="m4a"
BITRATE="192"

do_usage() {            # explanatory text
  echo "usage: ${ME} [-b nnn] [-e ext] [-f] [-c] [-r] [-v] [-h] [file list]"
  echo "       Convert music from AAC format to MP3"
  echo "  -l /path/app  Specify the location of lame(1)"
  echo "  -m /path/app  Specify the location of mplayer(1)"
  echo "  -b nnn        bitrate for mp3 encoder to use"
  echo "  -e ext        Use .ext rather than .m4a extension"
  echo "  -f            Force overwrite of existing file"
  echo "  -c            Delete original AAC|M4A file(s)"
  echo "  -s            Keep intermediate .wav file(s)"
  echo "  -v            Verbose output"
  echo "  -h            This information"
  exit 0
  }

do_error() {
  echo "$*"
  exit 1
  }

file_overwrite_check() {
  if [ "$FORCE" != "yes" ]
  then
    test -f "${1}" && do_error "${1} already exists."
  else
    test -f "${1}" && echo "  ${1} is being overwritten."
  fi
  }

create_wav() {  # use mplayer(1) to convert from AAC to WAV
  file_overwrite_check "${2}"

  test $VERBOSE && echo -n "Creating intermediate WAV file"

  ${AAC2WAV} -really-quiet -ao pcm "${1}" -ao pcm:file="${2}"
  if [ $? -ne 0 ]
  then
    echo ""
    echo "Conversion to WAV (${AAC2WAV}) failed."
    do_cleanup
    do_error "Exiting"
  fi

  test $VERBOSE && echo ".  OK"
  }

create_mp3() {  # use lame(1) to convert from WAV to MP3
  file_overwrite_check "${2}"

  test $VERBOSE && echo -n "Creating output MP3 file"

  ${WAV2MP3} -r -h -b ${BITRATE} -S "${1}" "${2}"
  if [ $? -ne 0 ]
  then
    echo ""
    echo "Conversion to MP3 (${WAV2MP3}) failed."
    do_cleanup
    do_error "Exiting"
  fi

  test $VERBOSE && echo ".  OK"
  }

do_cleanup() {  # Delete intermediate and (optionally) original file(s)
  test $VERBOSE && echo -n "Deleting intermediate file"
  test ${SAVEWAV} || rm -f "${2}"
  test ${RMM4A}   && rm -f "${1}"
  test $VERBOSE && echo ".  OK"
  }

do_set_bitrate() {
  test $VERBOSE && echo -n "Setting output bitrate to: $1 kbps"
  BITRATE=$1
  test $VERBOSE && echo ".  OK"
  }

GETOPT=`getopt -o l:m:b:e:cfhrv -n ${ME} -- "$@"`
if [ $? -ne 0 ]
then
  do_usage
fi

eval set -- "$GETOPT"

while true
do
  case "$1" in
    -l) LAME=$2 ; shift ; shift ;;
    -m) MPLAYER=$2 ; shift ; shift ;;
    -b) do_set_bitrate $2 ; shift ; shift ;;
    -e) EXT=$2 ; shift ; shift ;;
    -f) FORCE="yes" ; shift ;;
    -c) RMM4A="yes" ; shift ;;
    -s) SAVEWAV="yes" ; shift ;;
    -v) VERBOSE="yes" ; shift ;;
    -h) do_usage ;;
    --) shift ; break ;;
     *)  do_usage ;;
  esac
done

test -f $LAME    || do_error "$LAME not found. Use \"-l\" switch."
test -f $MPLAYER || do_error "$MPLAYER not found. Use \"-m\" switch."

if [ $# -eq 0 ]
then                    # Convert all files in current directory
  for IFILE in *.${EXT}
  do
    if [ "${IFILE}" == "*.${EXT}" ]
    then
      do_error "No files with extension ${EXT} in this directory."
    fi

    OUT=`echo "${IFILE}" | sed -e "s/\.${EXT}//g"`

    create_wav "${IFILE}"   "${OUT}.wav"
    create_mp3 "${OUT}.wav" "${OUT}.mp3"
    do_cleanup "${IFILE}"   "${OUT}.wav"

  done
else                    # Convert listed files
  for IFILE in "$*"
  do
    test -f "${IFILE}" || do_error "${IFILE} not found."

    OUT=`echo "${IFILE}" | sed -e "s/\.${EXT}//g"`

    create_wav "${IFILE}"   "${OUT}.wav"
    create_mp3 "${OUT}.wav" "${OUT}.mp3"
    do_cleanup "${IFILE}"   "${OUT}.wav"

  done
fi

exit 0

#!/bin/bash
# 
# m4a2wav
# 
for i in *.m4a; do
    out=$(ls $i | sed -e 's/.m4a//g')
    mplayer -ao pcm "$i" -ao pcm:file="$out.wav"
done

Note: the inputfiles shouldn't contain spaces (maybe we should sed those away too in the script?

2. wav to mp3

Now we can convert the wav's to mp3 or ogg or whatever we like. For example to convert to mp3 we can use this second script:

#!/bin/bash 
# 
# wav2mp3
# 
for i in *.wav; do
    out=$(ls $i | sed -e 's/.wav//g')
    lame -h -b 192 "$i" "$out.mp3"
done

That's it

Linux/Musik/ForMate/aacm4a/Scripts (last modified 2008-11-04 07:00:06)