guvcview software package provides GTK+ base UVC Viewer, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install guvcview
guvcview is installed in your system.
Make ensure the guvcview package were installed using the commands given below,
$ sudo dpkg-query -l | grep guvcview *
You will get with guvcview package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Graphics |
| Package | guvcview |
| Version | 2.0.4+debian-1 |
| Description | GTK+ base UVC Viewer |
| Sub Section | Graphics |