#!/bin/bash
#set -x
#
# @(#)vbr2linear  1.4.1 17/03/2015 Copyright 2007,2015 Robert M. Stockmann
#                                                      stock@stokkie.net
#

if [ "$1" == "" ]; then
  PROG=`basename $0`
  echo ""
  echo " vbr2linear repairs damaged mp3 audio files and converts them to a "
  echo " linear format, which then allows one to slide forth and back. Only "
  echo " skip frames when the audio file is broken. "
  echo " The original ID3 v1, v1.1 or v2 tags are preserved with the conversion. "
  echo ""
  echo "  Usage : $PROG \"fancy.file_ - _name.mp3\" <n> <br> stereo"
  echo "          <n>  = number of frames to skip"
  echo "          <br> = desired bitrate in kbits"
  echo "          stereo : add this to enforce stereo"
  echo "          mono   : add this to enforce mono"
  echo ""
  echo " If you specify <br> you must also specify <n>. If the audio file "
  echo " is not broken, simply specify 0 frames to skip, e.g."
  echo ""
  echo "          $PROG \"fancy.file_ - _name.mp3\" 0 32"
  echo ""
  echo " To enforce stereo or mono all options must be used and you might "
  echo " want to double <br> e.g."
  echo ""
  echo "          $PROG \"fancy.file_ - _name.mp3\" 0 64 stereo"
  echo ""
  echo " vbr2linear v1.4.1 has been tested with : "
  echo ""
  echo "          mpg123 version: 0.68, 1.3.1, 1.12.1 and 1.16.0 "
  echo "          sox: Version 12.17.4 and sox: SoX v14.4.1 "
  echo "          LAME version 3.92, LAME 64bits version 3.98.4."
  echo "          and LAME 64bits version 3.99.5 (http://lame.sf.net) "
  echo ""
else
	MPG_VERSION=`mpg123 --version | awk '{print $2}'`
	SOX_VERSION=`sox --version | awk '{print $3}'`
	VBR_TEMP=/tmp/vbr2linear.$$

	if [ "$MPG_VERSION" == "1.12.1" ]; then
		mpg123 -n 10 -o dummy "$1" > $VBR_TEMP 2>&1
	fi
	if [ "$MPG_VERSION" == "1.3.1" ]; then
		mpg123 -n 10 -o dummy "$1" > $VBR_TEMP 2>&1
	fi
	if [ "$MPG_VERSION" == "1.16.0" ]; then
		mpg123 -n 10 -o dummy "$1" > $VBR_TEMP 2>&1
	fi
	if [ "$MPG_VERSION" == "0.68" ]; then
		mpg123 -n 10 -a /dev/null "$1" > $VBR_TEMP 2>&1
	fi
	if [ "$SOX_VERSION" == "v14.3.0" ]; then
		BITS_OPT=" -b 16 "	
	elif [ "$SOX_VERSION" == "v14.4.1" ]; then
		BITS_OPT=" -b 16 "	
	else
		BITS_OPT=" -w "	
	fi

	TITLE=`cat "$VBR_TEMP" | grep Title: |\
		sed 's/Artist:.*$//' |\
		sed 's/^.*Title:/Title:/' |\
		sed 's/Title:   //' |\
		sed 's/Title:  //' | sed 's/  *$//'`

	ARTIST=`cat "$VBR_TEMP" | grep Artist: |\
		sed 's/Comment:.*$//' |\
		sed 's/^.*Artist:/Artist:/' |\
		sed 's/Artist:  //' |\
		sed 's/Artist: //' | sed 's/  *$//'`

	COMMENT=`cat "$VBR_TEMP" | grep Comment: |\
		sed 's/Album:.*$//' |\
		sed 's/^.*Comment:/Comment:/' |\
		sed 's/Comment: //' |\
		sed 's/Comment://' | sed 's/  *$//'`

	ALBUM=`cat "$VBR_TEMP" | grep Album: |\
		sed 's/Year:.*$//' |
		sed 's/^.*Album:/Album:/' |\
		sed 's/Album:   //' |\
		sed 's/Album:  //' | sed 's/  *$//'`

	YEAR=`cat "$VBR_TEMP" | grep Year: |\
		sed 's/Genre:.*$//' |\
		sed 's/^.*Year:/Year:/' |\
		sed 's/Year:    //' |\
		sed 's/Year:   //' | sed 's/  *$//'`

	GENRE=`cat "$VBR_TEMP" | grep Genre: |\
		sed 's/^.*Genre:/Genre:/' |\
		sed 's/Genre:   //' |\
		sed 's/Genre:  //' | sed 's/  *$//'`

	LGENRE=`lame --genre-list | grep "$GENRE"`
	if [ "$LGENRE" == "" ]; then
		GENRE=Speech
	fi

	SFREQ=`cat "$VBR_TEMP" | grep ^MPEG |\
		awk -F"," '{print $3}' | awk '{print $1}'`

	BRATE=`cat "$VBR_TEMP" | grep ^MPEG |\
		awk -F"," '{print $2}' | awk '{print $1}'`

	STYPE=`cat "$VBR_TEMP" | grep ^MPEG |\
		awk -F"," '{print $3}' | awk '{print $3}'`

	if [ "$STYPE" == "stereo" ]; then
		NCHAN=2
	elif [ "$STYPE" == "joint-stereo" ]; then
		NCHAN=2
	elif [ "$STYPE" == "mono" ]; then
		NCHAN=1
	fi

	if [ "$4" == "stereo" ] && [ "$NCHAN" == "1" ]; then
		MPG123_STEREO=" --stereo "
		NCHAN=2
	elif [ "$4" == "mono" ] && [ "$NCHAN" == "2" ]; then
		MPG123_STEREO=" --mono "
		NCHAN=1
	else
		MPG123_STEREO=""
	fi

	BASE=`echo "$1" | sed 's/\.mp3//'`
	echo " Converting $1 to $BASE.wav "
	if [ "$2" == "" ]; then
		mpg123 $MPG123_STEREO -q -s "$1" 2>/dev/null |\
			sox -t raw -r "$SFREQ" -s $BITS_OPT -c"$NCHAN" - "$BASE".wav
	else
		NFRAM="$2"
		mpg123 $MPG123_STEREO -k "$NFRAM" -q -s "$1" 2>/dev/null |\
			sox -t raw -r "$SFREQ" -s $BITS_OPT -c"$NCHAN" - "$BASE".wav
	fi
	echo " Done ..."
	exit 0

	if [ "$3" == "" ]; then
		LBR="$BRATE"
	else 
		LBR="$3"
	fi

	if [ -f $BASE.TAG ]; then
		. ./$BASE.TAG
	fi

	echo " Creating $BASE-linear.mp3"
	lame    --tt "$TITLE" --ta "$ARTIST"  --tl "$ALBUM" \
		--ty "$YEAR"  --tc "$COMMENT" --tg "$GENRE" \
		--quiet -h -b "$LBR" "$BASE".wav "$BASE"-linear.mp3 
	echo " Done ..."
	rm "$BASE".wav
	rm "$VBR_TEMP"
fi

exit 0