#!/bin/sh

# Looping virtual webcam

set -e

killall -9 ffmpeg || true

sleep 2

# unload virtual
sudo modprobe v4l2loopback -r -f

# create 2 virtual webcam
sudo modprobe v4l2loopback video_nr=21,22 card_label=virtcam1,virtcam2 exclusive_caps=1


# pipe actual webcam to virtcams
actualwebcam() {
    ffmpeg -f v4l2 -i /dev/video0 -codec copy -f v4l2 /dev/video21 -f v4l2 /dev/video22 >/dev/null 2>&1 </dev/null &
    echo $!
}

ffmpeg -re -stream_loop -1 -i ~/Video/stub.mp4 -f v4l2 -vcodec rawvideo -pix_fmt yuyv422 -framerate 30 /dev/video21 >/dev/null 2>&1 </dev/null &
SPID=$!
echo "showing static image, press ENTER for actualwebcam"
read C
kill -s INT $SPID

while true; do
    PID=$(actualwebcam)
    echo piping actual webcam, press ENTER to start recording
    read C
    echo recording, press [q] to replay
    ffmpeg -y -i /dev/video22 ~/Video/seq.mp4 >/dev/null 2>&1
    echo recording stopped
    ffmpeg -y -i ~/Video/seq.mp4 -vf reverse ~/Video/reversed.mp4 >/dev/null 2>&1
    echo reversed clip created
    ffmpeg -y -i ~/Video/seq.mp4 -i ~/Video/reversed.mp4 -filter_complex "[0:v] [1:v] concat=n=2:v=1 [v]" -map "[v]" ~/Video/loop.mp4 >/dev/null 2>&1
    echo looping clip created
    kill -s INT $PID
    echo webcam stopped, enter looping mode, press [q] to resume webcam
    ffmpeg -re -stream_loop -1 -i ~/Video/loop.mp4 -f v4l2 -vcodec rawvideo -pix_fmt yuyv422 -framerate 30 /dev/video21 >/dev/null 2>&1
done