Webcams

Handling transparency in the webcam plugins

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!

Troubleshooting

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