sync/scripts/reencode_m4a.sh

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

for file in ./*.m4a; do
   map='';
   if [[ $# > 0 && $1 == 'map' ]]; then
      map='-map 0:0';
   fi
   vbr='';
   if [[ $# > 1 && $2 == 'vbr' ]]; then
      vbr='libfdk_aac -profile:a aac_he -b:a 64k';
   else
      map="$map copy"
   fi
   dest=../reencode
   if [[ !(-d $dest) ]]; then
      mkdir $dest
   fi
   echo "ffmpeg -i '$file' -c:a $vbr $map -movflags +faststart '$dest/$file'";
   ffmpeg -i "$file" -c:a $vbr $map -movflags +faststart "$dest/$file";
done