Converts any audio/video source to a 320kbps MP3 file in the same directory using ffmpeg.

to-mp3.sh

#!/bin/bash

if [[ "$#" -ne 1 ]]; then
  echo "Usage: to-mp3.sh <input source>"
  exit 1
fi

set -ex

ffmpeg -hide_banner -loglevel warning -i "${1}" -b:a 320k "${1%.*}.mp3"