generate an ffmpeg command to mix all ur songs in a playlist

main.sh

#!/usr/bin/env bash

set -xeu

gen() {
    printf 'ffmpeg'

    for p in "$1"/*; do
        printf ' -i %q' "$p"
    done

    echo " -c:a aac -b:a 320k -filter_complex amix=inputs=$(ls "$1" | wc -l):duration=first:dropout_transition=2:duration=longest out.aac"
}

main() {
    rm -rf build

    mkdir build
    cd build

    eval "$(gen ../playlist)"
    ffmpeg -i out.aac -i ../cover.jpg -crf 24 -c:v copy -c:a aac -b:a 320k a.mp4
    ffmpeg -i a.mp4 -crf 24 -c:v copy -c:a aac -b:a 320k out.mp4

    rm -f a.mp4
}

main

https://www.youtube.com/watch?v=3R8e-OMmxXw btw