For installation in Ubuntu 20.04, the following command has to be run in the terminal:

$ sudo apt-add-repository ppa:qtcam/focal
$ sudo apt-get update
$ sudo apt-get install qtcam


For installation in Ubuntu 18.04, the following command has to be run in the terminal:

$ sudo apt-add-repository ppa:qtcam/bionic 
$ sudo apt-get update 
$  sudo apt-get install qtcam

For installation in Ubuntu 16.04, the following command has to be run in the terminal:

$ sudo apt-add-repository ppa:qtcam/xenial
$ sudo apt-get update
$ sudo apt-get install qtcam

For installation in Ubuntu 14.04, the following command has to be run in the terminal:

$ sudo apt-add-repository ppa:qtcam/trusty
$ sudo apt-get update
$ sudo apt-get install qtcam


Once the installation completes, running the command $ sudo qtcam would launch the application.