#!/bin/bash
tmp_dir=$1
number_of_files=$2
file_1=$3
file_2=$4

if [ $number_of_files != "2" ]
then
  ffmpeg -i $file_1 -map_channel 0.0.0 $tmp_dir/left.wav -map_channel 0.0.1 $tmp_dir/right.wav
else
  ffmpeg -i $file_1 -map_channel 0.0.0 $tmp_dir/left.wav
  ffmpeg -i $file_2 -map_channel 0.0.1 $tmp_dir/right.wav
fi