#!/bin/bash
#
# Convert a raw X/Y M/S H2n recording into a four channel A-format soundfile
#
# Copyright Fernando Lopez-Lezcano 2016
# nando@ccrma.stanford.edu
#
#  This program is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation, either version 3 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program.  If not, see <http://www.gnu.org/licenses/>.

if [ "$1" == "" ] ; then
    echo "usage: sphear_h2n_process_recording PATH/FILEPREFIX (SR00x where x is the recording number)"
    exit 1
else
    BASENAME=$1;
fi

XYFILE=${BASENAME}XY.WAV
MSFILE=${BASENAME}MS.WAV

if [ ! -r ${XYFILE} ] ; then
    echo "ERROR: could not find ${XYFILE}!"
    exit 1
fi
if [ ! -r ${MSFILE} ] ; then
    echo "ERROR: could not find ${MSFILE}!"
    exit 1
fi

# extract the directory path of the files
DIRNAME=`dirname $XYFILE`

# process XY
echo "processing XY files..."
sox ${XYFILE} ${DIRNAME}/a-format-4.wav remix 1
sox ${XYFILE} ${DIRNAME}/a-format-3.wav remix 2

# process MS and convert to individual mono files
echo "processing MS files..."
sox ${MSFILE} ${DIRNAME}/a-format-MSL.wav remix 1 gain 
sox ${MSFILE} ${DIRNAME}/a-format-MSR.wav remix 2 gain 2.0

# invert R
sox ${DIRNAME}/a-format-MSR.wav ${DIRNAME}/a-format-MSRI.wav remix 1i0
# M = L + R / 2
sox --combine mix ${DIRNAME}/a-format-MSL.wav ${DIRNAME}/a-format-MSR.wav ${DIRNAME}/a-format-1.wav gain 0.5
# S = (L - R) / 2
sox --combine mix ${DIRNAME}/a-format-MSL.wav ${DIRNAME}/a-format-MSRI.wav ${DIRNAME}/a-format-2.wav gain 0.5

# create a four channel A-format file
echo "creating AF file..."
AFFILE=`echo ${BASENAME}|sed 's|SR|AF|g'`
sox -M ${DIRNAME}/a-format-1.wav ${DIRNAME}/a-format-2.wav ${DIRNAME}/a-format-3.wav ${DIRNAME}/a-format-4.wav ${AFFILE}.WAV

echo "-- removing temporary files..."
rm -f ${DIRNAME}/a-format-*.wav

echo "-- done"