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Converting Audio Files from WMA or FLAC or OGG to MP3

It's easy and free to convert audio formats with open-source software on Linux, BSD, or similar!

You need to learn how to convert audio formats from the proprietary WMA or FLAC or the open-source OGG to MP3. We can easily do that with free open-source software including mplayer, flac, lame, mp3info, and others. Let's see how to do the conversions!

Converting WMA to MP3

WMA stands for Windows Media Audio, an audio data compression technology. Some players can handle WMA data directly, but many require MP3 (or, to be technical, MPEG-1 Audio Layer 3).

WMA data may be encapsulated within an ASF, or Advanced Systems Format, container file. ASF provides metadata, similar to ID3 tags in MP3 files, and may include digital rights management to limit your ability to play your music.

To convert foo.wma to foo.mp3 just run this sequence of commands:

$ mplayer -vo null -vc dummy -af resample=44100 -ao pcm:waveheader foo.wma
$ lame -m s -h audiodump.wav -o foo.mp3
$ mp3info -a "Artist name" -t "Song title" -l "Album name" foo.mp3 

If you have a bunch of files, there's a good chance that the file names contain embedded spaces, punctuation marks, and other Windows detritus. So you need to be careful when you automate this. Something like the following should work, use find to invoke a script:

$ cat convertor
mplayer -vo null -vc dummy -af resample=44100 -ao pcm:waveheader "$1"
lame -m s -h audiodump.wav -o "`echo $1 | sed 's/wma/mp3/'`"

$ find *.wma -exec ./convertor {} \; 

Then go through and label the files with mp3info.

Converting FLAC to MP3

FLAC stands for Free Lossless Audio Codec, another audio data compression algorithm. Unlike WMA and MP3, FLAC is lossless. This comes at the expense of larger file size, of course. And while FLAC is an excellent compression algorithm for lossless archival storage, players likely require MP3.

To convert foo.flac to foo.mp3

$ flac -dc foo.flac | lame --vbr-new /dev/stdin foo.mp3
$ mp3info -a "Artist name" -t "Song title" -l "Album name" foo.mp3 

Here's a shell script that will do the conversion, including extracting the FLAC tags and inserting them as MP3 tags in the result. Call it as something like:
/path/to/script foo.flac
and the result will be a new file named foo.mp3


MP3_FILE="`echo ${FLAC_FILE} | sed 's/\.flac/.mp3/'`"

metaflac --export-tags-to=/dev/stdout "${FLAC_FILE}" | 
	sed -e 's/=/="/' -e 's/$/"/' \
		-e 's/Album=/ALBUM=/' \
		-e 's/Genre=/GENRE=/' \
		-e 's/Artist=/ARTIST=/' > /tmp/tags-$$
cat /tmp/tags-$$
. /tmp/tags-$$
rm /tmp/tags-$$

flac -dc "${FLAC_FILE}" |
		lame -h -b 192 \
			--tt "${TITLE}" \
			--tn "${TRACKNUMBER}" \
			--ty "${DATE}" \
			--ta "${ARTIST}" \
			--tl "${ALBUM}" \
			--tg "${GENRE}" \
			--add-id3v2 /dev/stdin "${MP3_FILE}"

Converting OGG to MP3

Yes, if the creators of the FLAC file got overly imaginative with metacharacters within the tags, or just used strange strings for the "Genre" field, the above won't work precisely as written. Delete the optional tag parameters as needed.

Lame can't decode OGG and ffmpeg can't encode MP3, so use FLAC as an intermediate form:

$ ffmpeg -i foo.ogg foo.flac
$ flac -dc foo.flac | lame --vbr-new /dev/stdin foo.mp3
$ mp3info -a "Artist name" -t "Song title" -l "Album name" foo.mp3