Video baluns
What are they and How do they work?

A balun is a small transformer which converts an audio or video signal from unbalanced to balanced and vice versa (hence the term "bal*un"). By doing so, baluns make the necessary impedance adjustment for audio-visual signal transmission between different wiring systems. In all fairness, however, not all baluns are true "baluns;" the term balun has become a synonymous with any device which transmits audio and video over structured cabling.

VGA Baluns

Component Video Baluns

Composite Video Baluns