Find out what is using capture devices

fuser /dev/video0

Find out name of process

ps axl | grep ${PID}

Show info

v4l2-ctl --all

Set resolution and frame rate

v4l2-ctl -v width=1920,height=1080 --set-parm=60
v4l2-ctl -v width=3840,height=2160 --set-parm=30

Reset USB Device

usbreset "Live Streaming USB Device"

Show Stream in GUI

qvidcap

Create a virtual video capture device

sudo modprobe v4l2loopback devices=1 video_nr=10 card_label="OBS Cam" exclusive_caps=1

Automatically on Kernel Start up

Must install https://github.com/umlaeute/v4l2loopback

media-video/v4l2loopback on Gentoo

echo "v4l2loopback" > /etc/modules-load.d/v4l2loopback
echo "options v4l2loopback devices=1 video_nr=10 card_label=\"OBS Cam\" exclusive_caps=1" > /etc/modprobe.d/v4l2.conf

Run modprobe v4l2loopback after setting it up to load without restarting.