#!/bin/bash

INPUT_FILE="$1"
OUT_DIR="$2"
# get filename without extension
BASE_NAME="${INPUT_FILE##*/}"
# make filename with .mp3 extension
MP3_FILE="./${OUT_DIR}/${BASE_NAME%.*}.mp3"

mkdir -p "$OUT_DIR"
if [[ ! -f "$MP3" ]]; then
    ffmpeg -i "$INPUT_FILE" -c:a libmp3lame -b:a 320K -map a:0 -map v:0? -c:v copy "$MP3_FILE"
fi