Digital Keyers in Video Switchers and Effects Systems

Designing a digital video production switcher by simply copying the analog building blocks, adder for adder, multiplier for multiplier, can have inferior results. Digital technology offers opportunities for improvements that were not possible with analog circuitry. This article focuses on keyers and first explains how a keyer works in an analog switcher. It then shows how this implementation can result in jagged key edges in a digital keyer and presents a solution that can eliminate this problem. Self-keyers are discussed and a digital keyer that eliminates key fringing is presented.

Print ISSN

0036-1682

Published

1991-03

Content type

Original Research

DOI

10.5594/J02500