#!/usr/bin/env bash
set -euo pipefail

for file in ./*.m4a; do
   map='';
   if [[ $# > 0 && $1 == 'map' ]]; then
      map='-map 0:0';
   fi
   echo "ffmpeg -i '$file' -c:a copy $map -movflags +faststart '../reencode/$file'";
   ffmpeg -i "$file" -c:a copy $map -movflags +faststart "../reencode/$file";
done