#!/bin/sh

die() { echo >&2 "$@"; exit 1; }

[ $# -eq 3 ] || die "Syntax: $0 <input file> <output file> <vbr quality factor>"

[ -e "$1" ] || die "Input file does not exist: $1"

IN=`readlink -e $1`
OUT=$2
QFACTOR=$3

[ "$IN" = "$OUT" ] && die "Input file cannot be the same as the output file!"

COMMENTS="${IN}.comments"
PCM="${IN}.wav"

vorbiscomment -l $IN > $COMMENTS

( oggdec -o $PCM $IN && oggenc -q $QFACTOR -o $OUT $PCM ) || die "Recoding failed!"

vorbiscomment -w $OUT -c $COMMENTS || die "Could not restore comments!"

rm $PCM $COMMENTS