How to convert a m4a sound file to mp3?

Question

I tried to convert an .m4a file to an .mp3 file using ffmpeg with the following command:

$ ffmpeg -i music.m4a music.mp3

Unfortunately, I got a zero byte-sized file returned as output. The output of the command is as follows:

FFmpeg version 0.6-4:0.6-2ubuntu6.2, Copyright (c) 2000-2010 the FFmpeg developers
  built on Sep 16 2011 17:11:24 with gcc 4.4.5
  configuration: --extra-version=4:0.6-2ubuntu6.2 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-vaapi --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-gpl --enable-postproc --enable-x11grab --enable-libdc1394 --enable-shared --disable-static
  WARNING: library configuration mismatch
  libavutil   configuration: --extra-version=4:0.6-2ubuntu6.2 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-vaapi --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-gpl --enable-postproc --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  libavcodec  configuration: --extra-version=4:0.6-2ubuntu6.2 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-vaapi --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-gpl --enable-postproc --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  libavformat configuration: --extra-version=4:0.6-2ubuntu6.2 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-vaapi --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-gpl --enable-postproc --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  libavdevice configuration: --extra-version=4:0.6-2ubuntu6.2 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-vaapi --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-gpl --enable-postproc --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  libavfilter configuration: --extra-version=4:0.6-2ubuntu6.2 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-vaapi --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-gpl --enable-postproc --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  libswscale  configuration: --extra-version=4:0.6-2ubuntu6.2 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-vaapi --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-gpl --enable-postproc --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  libpostproc configuration: --extra-version=4:0.6-2ubuntu6.2 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-vaapi --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-gpl --enable-postproc --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  libavutil     50.15. 1 / 50.15. 1
  libavcodec    52.72. 2 / 52.72. 2
  libavformat   52.64. 2 / 52.64. 2
  libavdevice   52. 2. 0 / 52. 2. 0
  libavfilter    1.19. 0 /  1.19. 0
  libswscale     0.11. 0 /  0.11. 0
  libpostproc   51. 2. 0 / 51. 2. 0
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'music.m4a':
  Metadata:
    major_brand     : M4A 
    minor_version   : 0
    compatible_brands: M4A mp42isom
  Duration: 00:00:03.41, start: 0.000000, bitrate: 66 kb/s
    Stream #0.0(und): Audio: aac, 44100 Hz, mono, s16, 63 kb/s
Output #0, mp3, to 'music.mp3':
    Stream #0.0(und): Audio: 0x0000, 44100 Hz, mono, s16, 64 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
Encoder (codec id 86017) not found for output stream #0.0

How can I convert an .m4a sound file to an .mp3 file format?

Solution 1

The simple way to do it is:

ffmpeg -v 5 -y -i input.m4a -acodec libmp3lame -ac 2 -ab 192k output.mp3

If you want a script to wrap that, try aac2mp3, which should work for you. (The syntax for that last statement was pulled from there.) Inline code included below:

#!/bin/bash
#
# $Id: aac2mp3,v 1.2  03/30/2008 10:00 Daniel Tavares ([email protected]) - 
# Based on Script -  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}`
FFMPEG="/usr/bin/ffmpeg"
EXT="mp4"
BITRATE="128"
do_usage() {            # explanatory text
 echo "usage: ${ME} [-b nnn] [-e ext] [-f] [-c] [-r] [-v] [-h] [file list]"
 echo "       Convert music from AAC format to MP3"
 echo "  -m /path/app  Specify the location of ffmpeg(1)"
 echo "  -b nnn        bitrate for mp3 encoder to use"
 echo "  -e ext        Use .ext rather than .m4a extension"
 echo "  -f            Force overwrite of existing file"
 echo "  -c            Delete original AAC|M4A file(s)"
 echo "  -v            Verbose output"
 echo "  -h            This information"
 echo ""
 echo "For recursive directory, use: find -name '*.${EXT}' -exec ${ME} "{}" [args]     \;"
 exit 0
 }
do_error() {
 echo "$*"
 exit 1
 }
file_overwrite_check() {
 if [ "$FORCE" != "yes" ]
 then
   test -f "${1}" && do_error "${1} already exists."
 else
   test -f "${1}" && echo "  ${1} is being overwritten."
 fi
 }
create_mp3() {  # use ffmpeg(1) to convert from AAC to MP3
 file_overwrite_check "${2}"
 test $VERBOSE && echo -n "Converting file: ${1}"
 ${FFMPEG} -v 5 -y -i "${1}" -acodec libmp3lame -ac 2 -ab ${BITRATE}k "${2}";
 if [ $? -ne 0 ]
 then
   echo ""
   echo "Error!"
   do_cleanup
   do_error "Exiting"
 fi
 test $VERBOSE && echo ".  OK"
 }
do_cleanup() {  # Delete intermediate and (optionally) original file(s)
 test ${RMM4A} && rm -f "${1}"
 test $VERBOSE && echo ".  OK"
 }
do_set_bitrate() {
 test $VERBOSE && echo -n "Setting 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
   -m) FFMPEG=$2 ; shift ; shift ;;
   -b) do_set_bitrate $2 ; shift ; shift ;;
   -e) EXT=$2 ; shift ; shift ;;
   -f) FORCE="yes" ; shift ;;
   -c) RMM4A="yes" ; shift ;;
   -v) VERBOSE="yes" ; shift ;;
   -h) do_usage ;;
   --) shift ; break ;;
    *)  do_usage ;;
 esac
done
test -f $FFMPEG || do_error "$FFMPEG 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 "Not found ${EXT} in this folder."
   fi
   OUT=`echo "${IFILE}" | sed -e "s/\.${EXT}//g"`
   create_mp3 "${IFILE}" "${OUT}.mp3"
   do_cleanup "${IFILE}" 
 done
else                    # Convert listed files
 for IFILE in "$*"
 do
   test -f "${IFILE}" || do_error "${IFILE} not found."  
   OUT=`echo "${IFILE}" | sed -e "s/\.${EXT}//g"`    
   create_mp3 "${IFILE}" "${OUT}.mp3"
   do_cleanup "${IFILE}"    
 done    
fi   
exit 0

Solution 2

This worked for me on Ubuntu 14.04:

avconv -i input.m4a ouptut.mp3

To obtain the avconv command, install libav-tools :

sudo apt-get install libav-tools

Solution 3

SoundConverter can do this without having to mess around on the command-line, and it's available in the Ubuntu Software Center:

Solution 4

I needed an alternate solution because - my files were sitting in recursive subdirectories - I had spaces in paths.

So I eventually settled for :

 find . -type f -name '*.m4a' -exec bash -c 'avconv -i "$0" "${0/%m4a/mp3}"' '{}' \;

Then deleted the original files :

find . -type f -name '*.m4a' -exec bash -c 'rm "$0"' '{}' \;

Solution 5

I created a script to do this.

My requirements were:

• Must maintain as many tags as possible
• Must retain album artwork if exists
• Must be 320K mp3s

Works on all m4a files in a directory, and outputs the new shiny Mp3s into a folder the script creates called Mp3. Warning; this script overwrites existing Mp3s in the output folder if they have the same name. Also uses files 'metadata.txt' and 'metadata2.txt' as temp files.

You'll need to install avconv if it doesn't exist already.

I couldn't figure out how to persist the 'Year' tag into ID3v1 tags, so I didn't enable that option.

#!/bin/bash
files=*.m4a
#create output folder if it doesnt exist
if [ ! -d Mp3 ]; then
        mkdir Mp3
fi

for file in $files; do
        mp3File=${file/%m4a/mp3}
        avconv -y -i "${file}" -f ffmetadata metadata.txt
        sed -e 's/^date=\(.*\)$/TYER=\1/' -e 's/^major_brand=.*$//' -e 's/^minor_version=.*$//' -e 's/^creation.*$//' -e 's/^compatible.*$//' -e 's/^encoder=.*$//' <metadata.txt >metadata2.txt
        avconv -y -i "${file}" -i metadata2.txt -ab 320k -map_metadata 1 -id3v2_version 3 "Mp3/${mp3File}"
done

Save it as 'convert.b', and then run the script by typing:

% bash convert.b

View more solutions

Comments

[Braden Best]

Install avconv and use this script: gist.github.com/bradenbest/cfba10c9df4b4c0daaab. You can also configure the fformat and tformat vars to change what audio formats you're converting between.

[Aaron John Sabu]

Your question was my answer :-D

[The Student]

Got (after many lines of text): Unknown encoder 'libmp3lame' Error! Exiting. With apt-get I can see libmp3lame0 and libmp3lame-dev. I tried to install libmp3lame0, but nothing changed.

[jefe goode]

If you don't want to compile ffmpeg: sudo apt-get install libavcodec-extra-53

[HDave]

If you have your files tagged by MusicBrainz, then find another solution: bugs.launchpad.net/soundconverter/+bug/1174949

[Denilson Sá Maia]

ffmpeg has been replaced by avconv in newer Ubuntu/Debian releases. See askubuntu.com/questions/432542/… and install libav-tools

[Peter Flynn]

Christ on a crutch, what a mess. Soundconverter failed because Python was missing some packages, then it popped up an installer window for over 20 more packages, none of which it could install, of course, because it wasn't running as root, of course. Someone needs to rewrite the installer and the dependencies.

[Peter Flynn]

This does not work because ffmpeg is not in the Ubuntu repos...and nor are avconv or libav-tools. Could whoever is in charge of audio software please stop footling around and settle on something stable?

[Admin]

Program does not load Ubuntu 14.04

[krumpelstiltskin]

there is currently a bug in soundconverter related to m4a: bugs.launchpad.net/soundconverter/+bug/1512007

[David Davies-Jones]

FFMPEG is not deprecated. AvConv was a fork that decided to put that message in when somebody called it by the FFMPEG executable name

[ctrl-alt-delor]

I am trying to avoid messing around with the gui: I want to automate it.

[Mark Slater]

For me, this is the top answer. A small point - the deletion can be expressed more succinctly as: find . -type f -name '*.m4a' -delete

[bomben]

I modified the command by adding -y and -b:a 256k to make sure the program does not halt to ask for permission to overwrite existing mp3-files, and for a better quality (although I did not recognise a difference between the standard output of 128kbit/s (which was only half the bitrate my original m4a's had been): find . -type f -name '*.m4a' -exec bash -c 'avconv -i "$0" -y -b:a 256k "${0/%m4a/mp3}"' '{}' \;

[Rom098]

This is exactly what I'm looking for.

[Eduardo Lucio]

'EXT="mp4"' needs to be changed to 'EXT="m4a"' according to the question. I would add the following explanatory text to make the understanding simpler: '# EXAMPLE: Will convert all files in the current directory with extension # "m4a" to "mp3" # bash SCRIPT_NAME -b 256 -v'

[Kevin Bowen]

This command can be used successfully by substituting 'ffmpeg' for 'avconv'.

[Kevin Bowen]

As of 15.04, ffmpeg is back in the repos: webupd8.org/2014/11/ffmpeg-returns-to-official-ubuntu.html As of 18.04, libav-tools and avconv are no longer available.

[Kevin Bowen]

FYI. As of 18.04, libav-tools and avconv are no longer included in repos.

[Radon Rosborough]

Just using ffmpeg directly, as specified in the question, works fine for me with ffmpeg 4.1.3 on macOS 10.14.4.

[George Udosen]

killer script, change the avconv to ffmpeg and that did the job. Please update the answer to include explanation for the various commands!

[davernator]

Upvote. It worked as-is. Nice script there as well (:-).

[Giulia]

Oh thank you thank you...

[Csaba Toth]

I liked this one because I could easily parametrize lame. Somehow ffmpeg parametrization was a nightmare. For lame I just give -V 0 or -V 3 or something like that.

[fitojb]

Very convenient! The only drawback I see is that this method seems to lose the metadata in the files, but I might have missed to check a box somewhere.