A Buyer's Guide to Video Production Switchers

For streaming, the question of whether you need embedded audio or external audio is determined by the available inputs on the webcast encoder. Embedded audio has the advantage of easy distribution amplification if additional video outputs are required for the archive recording.

Input Frame Rates and Scaling

What are the available input frame rates, and is scaling available? Especially when working with computer inputs, it's common to work with different frame and refresh rates. Some video switchers have the ability to both internally convert frame rates and scale video inputs. When this isn't available, you may need an external scaler or converter for noncompliant inputs.

Streaming, like most modern video viewing, is done with progressive video, rather than interlaced video. Unfortunately, many video cameras and video switchers do not have a common progressive frame rate available from the video camera's live video output. The video output is different from the available internal recording options on the video camera. This has resulted in 60i being the most common signal, rather than the 30p that is typically webcast, although in most cases you won't need to deinterlace because 60i on a native 30p or 60p CMOS sensor doesn't show interlacing artifacts or scan lines the same way that a traditional 60i signal from a CCD sensor would.

Other Features

Above and beyond these basic specifications and the features available on most video switchers, some models have downstream and upstream keyers as well as internal media players, or they have special connections such as MIDI, USB class streaming outputs, tally lights, and even two-way fiber video and talk-back connections.

Ultimately, cost is going to be a consideration. It's common to budget for a video switcher what you would spend on the individual video cameras that will feed its inputs.

Five Key Questions to Ask When Choosing a Production Switcher

• What is the form factor of the control panel and video switcher?
• What are the input types, and how many inputs are available?
• What are the output types, and how many are available?
• What are the video switcher's audio capabilities?
• What are the available input frame rates, and is scaling available?

This article appears in the forthcoming 2013 Streaming Media Industry Sourcebook.