#!/usr/bin/env bash

# form table of frame RMS sound levels
listfile=$(mktemp)
ffmpeg -i "$1" -af astats=metadata=1:reset=10,ametadata=print:key=lavfi.astats.Overall.RMS_level:file=$listfile -f null -

# convert list to csv file
data_file=$(mktemp)
cat $listfile | tr -d '\n' | tr 'O' '\n' | tr 'f' ' ' | tr 'l' ' ' | tr -d '=' | tr ':' ' ' | awk '{print $10 "," $4}' | head -n -4 | tail +4 > $data_file

# form output file
outfile="${1}.soundchart.png"

gnuplot <<-EOFMarker
reset
set datafile separator ","
set title "Memory"
set xlabel "Time"
set ylabel "Level, dB"
set xdata time
set timefmt "%s"
set format x "%H:%M:%S"
set key left top
set grid
set term png size 3840,2160
set output "$outfile"
plot "$data_file" using 1:2 title "1" with lines
EOFMarker

rm -v $listfile
rm -v $data_file