Images are read as 8bits luminance values (0 = black, 255 = white)
Set the layer mode to Overlay
on a webcam plugin, all black pixels become transparent, so you can see the previous plugin’s result in the black zones of the webcam !
In case your webcam is not recognized, you can use a V4L2 loopback device.
Install the kernel module:
$ sudo apt install v4l2loopback-dkms
Redirecting a webcam on /dev/video2
to /dev/video0
:
$ sudo modprobe v4l2loopback $ ffmpeg -i /dev/video2 -video_size 640x480 -pix_fmt yuyv422 -f v4l2 -vf hflip -s 640x480 /dev/video0