Cut a video out of a long recording with fade in and out and volume normalization

videocuttter.sh

#!/bin/bash

INFILE="input_video.mp4"
FPS=30

get_seconds() {
	local seconds=0
	IFS=":" read -ra T <<< "$1"
	for x in "${T[@]}"; do
		seconds=$(echo "$seconds * 60 + $x" | bc)
	done
	echo $seconds
}

if [[ "$#" -ne 3 ]]; then
	echo "Usage: $0 <start time> <stop time> <out file name>"
	exit 1
fi

start="$1"
stop="$2"
outfname="$3"
framestart="$( echo "$(get_seconds $start) * $FPS / 1" | bc)"
framestop="$( echo "($(get_seconds $stop) - 1) * $FPS / 1" | bc)"
ffmpeg -i "$INFILE" -ss $start -to $stop \
	-vf 'fade=in:'${framestart}:$FPS', fade=out:'${framestop}:$FPS \
	-af 'afade=in:st='$(get_seconds $start)':d=1, afade=out:st='$( echo "$(get_seconds $stop) - 1" | bc)':d=1, loudnorm=dual_mono=true:print_format=summary:I=-18' \
	-c:v libx264 -ar 48000 -c:a aac \
	${outfname}.mkv