reverse an mp4 video

oediv

#!/bin/sh

[ $# -ne 2 ] && exec echo "Usage: ${0##*/} <input> <output>"

src=$1
dst=$2
dir=$(mktemp -d)

trap "rm -rf $dir" EXIT

fps=$(ffprobe -v 0 -of csv=p=0 -select_streams v:0 -show_entries stream=r_frame_rate "$src")

ffmpeg -loglevel warning -stats -i "$src" -an "$dir/%06d.png"
ffmpeg -loglevel warning -stats -i "$src" -vn "$dir/audio.wav"
sox "$dir/audio.wav" "$dir/backwards.wav" reverse
cat $(ls -r $dir/*.png) | ffmpeg -loglevel warning -stats -y -f image2pipe -vcodec png -r $fps -i - -i "$dir/backwards.wav" -preset slower -crf 22 "$dst"