#!/bin/bash
#
# Date:    2009-11-30
# Author:  Ole Kristian Lien
# License: GNU General Public License
#
# Splits stereo channel into left and right, then
# combines them  back into an audio file (stereo)

BITRATE=`./audio_bitrate $1`
EXT=`echo "$1"|awk -F . '{print $NF}'`
NAME=`basename $1 .$EXT`

if [ -z "$1" ]; then
	echo "Usage: $0 <audio-file>"
	exit 1
fi

sox $1 -c 1 left.wav mixer -l 2> /dev/null
sox $1 -c 1 right.wav mixer -r 2> /dev/null
sox -m left.wav right.wav mono.wav 2> /dev/null
sox mono.wav -c 2 stereo.wav 2> /dev/null
ffmpeg -i stereo.wav -acodec $EXT -ab "$BITRATE"k $NAME-new.$EXT 2> /dev/null
rm left.wav right.wav mono.wav stereo.wav