Around 2012, I joined with two friends to start a company called Epic Entertaiment. Our main product was KaraOTec. it is a software intended to be used in rockolas.
There is an old demo in youtube (https://www.youtube.com/watch?v=avlkyhIsGWs)
The software was being selled with a licence to use in one machine only, the code for validating a license is still here, is not the best option but the best one coming to me in that time.
A rockola is a set of hardware designed to play music, watch videos, and sing karaoke (that's something very popular in Mexico for short budget parties), it have specific buttons to handle these actions.
The software was designed to run in Ubuntu but can run in many Linux based systems having the required dependences installed, some features were designed based on Ubuntu which may not work in other systems.
The software have the most common features in these kind of systems and supports loading content from external devices which are detected in real time.
The support for drawing content from CDG files was done using the source code from plarpebu project (https://sourceforge.net/projects/plarpebu/)
The video was supported using vlcj (https://github.com/caprica/vlcj) which is not included in this package, at that time, vlcj was not supported for ARM devices.