Video Switchers

The video switcher is the keystone around which the rest of the TV studio is built. The switcher is a piece of equipment that allows you to choose from many incoming video sources and make transitions or other special effects between those sources. The sophistication of a switcher determines what transitions can be used between shots, what kind of special effects can be used, and how frequently they can be used. The capabilities of various switchers run from the very simple to the mind-boggling, and their prices follow suit.

Vertical Interval Switchers

The standard type of switcher is the vertical interval switcher. This switcher has special circuitry that delays any cuts until the entire system is in vertical blanking — the vertical interval. Since vertical blanking happens 60 times a second, the delay is very small — imperceptible to humans — but it ensures sharp, clean cuts every time. Anything that is going to be switched for use on the air must go through a vertical interval switcher.

Component Switchers

The next type of switcher is the component switcher. Rather than using the complete encoded color signal, this switcher deals with the individual red, green, and blue components separately. It's almost like having three separate switchers combined into one package. The three color components travel through the switcher in parallel. This generally produces a much sharper picture and crisper special effects.

Digital Switchers

As the video industry moves to digital video, we also need switchers that are digital. Rather than processing an analog stream of changing voltages, the digital switcher processes a stream of digital information. Just as with analog switchers, some digital switchers are designed to handle a single composite digital signal while others will handle separate component digital signals.

Special Effects

Virtually all production switchers today come with special-effects capabilities. How many of those special effects there are, what they are, how well they work, and how they can be used in sequences all affect the price of the switcher. The most common switcher-effects capabilities will be discussed later.