Introduction

I found myself having issues trying to play DVD in VLC on Debian.

Here are the couple steps that I had to do to resolve my issue.

Install DVD Libraries

First thing is to install the dvd libraries that, some codecs and regionset:

sudo apt install libdvd-pkg regionset libavcodec-extra

libdvd-pkg need to be compiled and install additional libraries by running:

sudo dpkg-reconfigure libdvd-pkg

Changing DVD region codes

Having bought my computer in France, I never though about encryption and copyrights that were set on DVD. DVD would be loading but being unable to play. For fixing it, I had to change the region code of the DVD firmware:

sudo regionset /dev/sr0

Then set the proper region set for the DVD:

1. North America (USA and Canada)
2. Europe, Middle East, South Africa and Japan
3. Southeast Asia, Taiwan, Korea
4. Latin America, Australia, New Zealand
5. Former Soviet Union (Russia, Ukraine, etc.), rest of Africa, India
6. China

Source: https://www.cyberciti.biz/faq/installing-plugins-codecs-libdvdcss-in-debian-ubuntu-linux/