Simple script for resampling a drumgimzo kit using sox

dg_resample.sh

#! /bin/bash

#
# Simple script for resampling a drumgimzo kit using sox
#
# Author: Agus Terol - agus3985@gmail.com
# License: GPLv3 - https://www.gnu.org/licenses/gpl-3.0.html
#

function print_usage
{
  echo "DGResample - Simple script for resampling a drumgimzo kit using sox"
  echo ""
  echo "Usage: dg_resample.sh [-h|-v] INPUT_DIR OUTPUT_DIR [SAMPLE_RATE]"
  echo ""
  echo "    INPUT_DIR       directory that contains the drumgizmo kit to be resampled"
  echo "    OUTPUT_DIR      directory where the resampled drumgizmo kit is going to saved"
  echo "    SAMPLE_RATE     (optional) sample rate parameter to be passed to sox."
  echo "                    Default value is 48000."
  echo ""
  echo "    -h, --help      print this help"
  echo "    -v, --verbose   print verbose messages"
  echo ""
  echo "Author: Agus Terol - agus3985@gmail.com"
  echo "License: GPLv3 - https://www.gnu.org/licenses/gpl-3.0.html"
}

# Arguments parsing
if [ "$#" -eq 0 -o "$1" = "-h" -o "$1" = "--help" ]
then
  print_usage $0
  exit 0
fi

VERBOSE=0
MKDIR_VERBOSE_FLAGS=""
CP_VERBOSE_FLAGS=""
SOX_VERBOSE_FLAGS=""
if [ "$1" = "-v" -o "$1" = "--verbose" ]
then
  VERBOSE=1
  MKDIR_VERBOSE_FLAGS="-v"
  CP_VERBOSE_FLAGS="-v"
  SOX_VERBOSE_FLAGS="-S"
  shift
fi

if [ "$#" -lt 2 ]
then
  echo "ERROR: Incorrect arguments" >&2
  print_usage $0
  exit 1
fi

INPUT_DIR=$1
OUTPUT_DIR=$2
SAMPLE_RATE=48000
if [ ! -z "$3" ]
then
  SAMPLE_RATE=$3
fi

# Check input directory exists
if [ ! -d "$INPUT_DIR" ]
then
  echo "ERROR: Directory '$INPUT_DIR' does not exist!" >&2
  exit 1
fi 

# Check output directory does not exist
if [ -d "$OUTPUT_DIR" ]
then
  echo "ERROR: Directory '$OUTPUT_DIR' exists!" >&2
  exit 1
fi 

# Check sox exists in PATH
WHICH_SOX=$(which sox)
if [ -z "$WHICH_SOX" ]
then
  echo "ERROR: Command 'sox' not found. Please install it and/or be sure it is in PATH" >&2
  exit 1
fi

IFS=$'\n'

# Replicate folder structure
for i in $(find "$INPUT_DIR" -type d)
do
  mkdir $MKDIR_VERBOSE_FLAGS -p "$OUTPUT_DIR/$(realpath --relative-to="$INPUT_DIR" $i)"
done

# Copy non .wav files
for i in $(find "$INPUT_DIR" -type f -not -iname "*.wav")
do
  cp $CP_VERBOSE_FLAGS "$i" "$OUTPUT_DIR/$(realpath --relative-to="$INPUT_DIR" $i)"
done

# Resample .wav files to $SAMPLE_RATE
for i in $(find "$INPUT_DIR" -iname "*.wav")
do
  o="$OUTPUT_DIR/$(realpath --relative-to="$INPUT_DIR" $i)"
  sox $SOX_VERBOSE_FLAGS "$i" "$o" rate -v -s -L $SAMPLE_RATE
  if [ $VERBOSE -eq 1 ]
  then
    sox --info "$o"
  fi
done

# Modify XML kits definitions for modifiying or adding samplerate="$SAMPLE_RATE" attribute to the drumkit element
for i in $(find "$OUTPUT_DIR" -maxdepth 1 -type f -iname "*.xml")
do
  grep -q "<drumkit" "$i"
  if [ $? -eq 0 ]
  then
    # If this XML file has a drumkit element...
    grep -q "samplerate" "$i"
    if [ $? -eq 0 ]
    then
      # ...and if it has already a samplerate attribute, then modify it
      sed -i "s/\(<drumkit.*samplerate=\"\).*\(\".*>\)/\1$SAMPLE_RATE\2/" "$i"
    else
      # ...and if it does not have a samplerate attribute yet, then add it
      sed -i "s/\(<drumkit .*\)>/\1 samplerate=\"$SAMPLE_RATE\">/" "$i"
    fi
  fi
done