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Script to convert WMA to MP3 on Linux

From: "andrew cooke" <andrew@...>

Date: Thu, 1 Jan 2009 13:03:51 -0300 (CLST)

This simply uncompresses the wma file and then re-encodes it as mp3.  It
uses a fifo rather than a temporary file to avoid writing to disk (much
faster than the temporary file approach, but the uncompressed intermediate
file is big).

It's difficult to know what quality setting to use - since the wma file
was already compressed, anything other than "perfect" is going to lose
even more information.  On the other hand, there's no point in using crazy
quality if the details have already been thrown away.  So I just opted for
variable bit rate and let the encoder decide.

Typical results have similar file sizes in some quick tests I made, but
one file was ten times bigger as an mp3.  I don't know why.

This is based on the scripts at the link given below; I just reformatted,
fixed options that had changed slightly, and used vbr.

Note that mplayer will require appropriate codecs.  For me that meant that
the ffmpeg library was needed.

#!/bin/bash

# Dump wma to mp3
# from http://ocaoimh.ie/2005/08/16/how-to-convert-from-wma-to-mp3/

for src in *.wma
do
  if [ -f "$src" ]
  then
    fifo=`echo "$src"|sed -e 's/wma$/wav/'`
    rm -f "$fifo"
    mkfifo "$fifo"
    mplayer -vo null -vc dummy -af resample=44100 -ao pcm:waveheader
"$src" -ao pcm:file="$fifo" &
    dest=`echo "$src"|sed -e 's/wma$/mp3/'`
    lame --vbr-new "$fifo" "$dest"
    rm -f "$fifo"
  fi
done

Single Line

From: andrew cooke <andrew@...>

Date: Sun, 4 Oct 2009 08:45:18 -0400

One line above was split across multiple lines.  The text below should
work woth cut + paste.

Andrew

#!/bin/bash

# Dump wma to mp3
# from http://ocaoimh.ie/2005/08/16/how-to-convert-from-wma-to-mp3/

for src in *.wma
do
  if [ -f "$src" ]
  then
    fifo=`echo "$src"|sed -e 's/wma$/wav/'`
    rm -f "$fifo"
    mkfifo "$fifo"
    mplayer -vo null -vc dummy -af resample=44100 -ao pcm:waveheader \
"$src" -ao pcm:file="$fifo" &
    dest=`echo "$src"|sed -e 's/wma$/mp3/'`
    lame --vbr-new "$fifo" "$dest"
    rm -f "$fifo"
  fi
done

Shorter variant, using Bash redirections...

From: Jason Dusek <jason.dusek@...>

Date: Wed, 21 Sep 2011 04:01:34 +0000

#!/bin/bash
set -o nounset -o errexit -o pipefail
# Dump wma to mp3
# from http://ocaoimh.ie/2005/08/16/how-to-convert-from-wma-to-mp3/
for src in *.wma
do
  if [[ -f "$src" ]]
  then
    mplayer "$src" -vo null -vc dummy -af resample=44100 \
            -ao pcm:waveheader \
            -ao pcm:file=>(lame --vbr-new - "${src%wma}"mp3)
  fi
done

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