A bash script that allows the user to pick a gphoto2 compatible camera connected to their linux device to create a virtual webcam using v4l2loopback

dslr-webcam-selector.sh

#!/bin/bash

##
# Error "An error occurred in the io-library ('Timeout reading from or writing to the port'): No error description available ERROR: Movie capture error... Exiting."
# -> https://github.com/gphoto/gphoto2/issues/495
##


generate_virtual_camera_names() {
    local length=$1
    local test_strings=()
    for i in $(seq 0 $((length - 1))); do
        test_strings+=("Virtual_Camera_$i")
    done
    (IFS=,; echo "${test_strings[*]}")
}

generate_virtual_camera_ids() {
    local length=$1
    local test_strings=()
    for i in $(seq 0 $((length - 1))); do
        test_strings+=($((10 + $i)))
    done
    (IFS=,; echo "${test_strings[*]}")
}


cleanup () {
  echo; echo 'Removing v4l2loopback'
  sudo modprobe -r v4l2loopback
  echo; echo 'Removing /dev/video10 device'
  sudo rm -fr /dev/video10
}

if [[ $1 == "cleanup" ]]; then
    echo "Cleaning things up..."
    cleanup
    exit 0
fi

on_exit () {
  trap TERM
  cleanup  
  exit 0
}

trap "on_exit" INT  


start_camera() {
  echo "Attaching camera $1 to virtual device at /dev/video10"
#   gphoto2 --port $1 --stdout --capture-movie | ffmpeg -hide_banner -loglevel panic -nostats -i - -vcodec rawvideo -pix_fmt yuv420p -f v4l2 /dev/video10
  gphoto2 --port $1 --stdout --capture-movie | ffmpeg -i - -vcodec rawvideo -pix_fmt yuv420p -f v4l2 /dev/video10
}

create_virtual_camera() {
  echo "Creating virtual camera device /dev/video10"
  echo;
  #sudo modprobe v4l2loopback exclusive_caps=1 video_nr=10,11 card_label="Virtual Camera","Virtual Camera Aux" 
  sudo modprobe v4l2loopback exclusive_caps=1 video_nr=10 card_label="Virtual Camera" devices=1
  echo;
}



##########
## Menu
# By Alexander Klimetschek
# At https://unix.stackexchange.com/a/415155
##########

function select_option {

    # little helpers for terminal print control and key input
    ESC=$( printf "\033")
    cursor_blink_on()  { printf "$ESC[?25h"; }
    cursor_blink_off() { printf "$ESC[?25l"; }
    cursor_to()        { printf "$ESC[$1;${2:-1}H"; }
    print_option()     { printf "   $1 "; }
    print_selected()   { printf "  $ESC[7m $1 $ESC[27m"; }
    get_cursor_row()   { IFS=';' read -sdR -p $'\E[6n' ROW COL; echo ${ROW#*[}; }
    key_input()        { read -s -n3 key 2>/dev/null >&2
                         if [[ $key = $ESC[A ]]; then echo up;    fi
                         if [[ $key = $ESC[B ]]; then echo down;  fi
                         if [[ $key = ""     ]]; then echo enter; fi; }

    # initially print empty new lines (scroll down if at bottom of screen)
    for opt; do printf "\n"; done

    # determine current screen position for overwriting the options
    local lastrow=`get_cursor_row`
    local startrow=$(($lastrow - $#))

    # ensure cursor and input echoing back on upon a ctrl+c during read -s
    trap "cursor_blink_on; stty echo; printf '\n'; exit" 2
    cursor_blink_off

    local selected=0
    while true; do
        # print options by overwriting the last lines
        local idx=0
        for opt; do
            cursor_to $(($startrow + $idx))
            if [ $idx -eq $selected ]; then
                print_selected "$opt"
            else
                print_option "$opt"
            fi
            ((idx++))
        done

        # user key control
        case `key_input` in
            enter) break;;
            up)    ((selected--));
                   if [ $selected -lt 0 ]; then selected=$(($# - 1)); fi;;
            down)  ((selected++));
                   if [ $selected -ge $# ]; then selected=0; fi;;
        esac
    done

    # cursor position back to normal
    cursor_to $lastrow
    printf "\n"
    cursor_blink_on

    return $selected
}

echo "Select one option using up/down keys and enter to confirm:"
echo

options=$(gphoto2 --auto-detect | awk 'NR > 2 { print $0 }')

IFS=$'\n' read -d '' -ra optionsArr <<< "$options"

select_option "${optionsArr[@]}"
choice=$?

echo "Creating Virtual Camera for ${optionsArr[$choice]}"

echo "..."

cleanup

sleep 1
create_virtual_camera

name=$(echo ${optionsArr[$choice]} | sed 's/\susb:/\n/g' | awk 'NR==1')
port=usb:$(echo ${optionsArr[$choice]} | sed 's/\susb:/\n/g' | awk 'NR==2')

sleep 1
start_camera "${port% }"