spectro.sh

#!/bin/bash
folder="spectrogram";
declare -a formats=("mp3" "m4a" "ogg" "aac" "flac");
rm -rf "$folder";
mkdir "$folder";
for f in *."${formats[@]}" **/*."${formats[@]}"; do
    if [ -f "$f" ]; then
        echo "./$f";
        if ! [ -f "./${f##*/}" ]; then
            mkdir -p "$folder/${f%/*}";
        fi
        ffmpeg -i "$f" -lavfi showspectrumpic "$folder/${f%.*}".png -y;
    fi
done