This small script is to memoize a fast convertion of ffmpeg

convert.sh

#!/usr/bin/env bash

for i in *.MP4;
  do name=`echo $i | cut -d'.' -f1`;
  FILE="small/${name}_small.MP4"
  if [ -f "$FILE" ]; then
    echo "$FILE exist"
  else
    echo "$FILE does not exist. Creating..."
    ffmpeg -i "$i" "${FILE}";
  fi

done