Production switchers

One has to wonder why production switchers are not more appropriately named. While they still mix signals, switchers now perform vastly more complex and expansive functions.

When the first modern switcher company started in Grass Valley, CA, a synchronous switch or a dissolve was sometimes considered an accomplishment. Many of us remember timing sources to a switcher before every production to avoid dissolves sliding in from left field. Wipes beyond horizontal, vertical, diagonal and circular were a challenge and were optional features that one could add at the time of purchase.

Today, a switcher's dizzying array of features can turn a good technical director into a great one. Picture and key repositioning are standard on most switchers. Digital video effects are often integrated into a seamless operator control panel. Even standards conversion allows some HD switchers to include SD and HD inputs from another standard.

Mixing signals (vision signals or pictures) is the root purpose of a switcher. But today's modern systems feature machine control, still stores, clip recorders and DVEs. In a sense, switchers have become the hub of video production. These holistic systems combine the functionality of multiple devices.

The paradox of complexity

Today's switchers have taken on much of the functionality of entire control rooms of the past. However, this complexity presents a paradox.

Much more is expected of a technical director today. Without panel memory or EMEM, a lot of what is done live on-air today simply requires the work of more than one person. Today's huge control panels feature hundreds of buttons and soft keys that change seemingly at will, which limits an engineer's ability to absorb the complete production environment.

Many large events, such as the Academy Awards, cannot be produced without at least two technical directors controlling the switchers. And additional personnel are required to run the many channels of playback that fit into flying boxes and on-set displays.

This complexity requires a new approach to training. Experienced technical directors who can demonstrate how to use switchers' new capabilities must train users. When buying a switcher, it's important to buy the best training package available — and not for just one person.

Dual processing power

A critical element emerging in the switcher market is the ability to remain useful during crossover market years. HDTV has finally taken off, eight years after the FCC asked the top 10 markets to initiate digital broadcasting. Unfortunately, much of what we see today, and virtually all legacy production content and file footage, is still produced in 4:3 SD.

One solution is a production environment with aspect ratio converters and standards converters in sufficient quantity to support external conversion of non-HD content. I once worked on a large control room project, and the conversion hardware was more expensive and complex than anything else in the design. There were more than 40 pieces of equipment.

As an alternative, manufacturers have fortunately recognized the opportunity for a niche and made switchers that can process more than one standard at a time. This allows legacy content to be seamlessly integrated without complex routing and conversion planning.

As time goes on, I suspect this capability will be more common. The first switcher that offered seamless integration keyed the nonmatching format in each mix effects. This was somewhat limiting, but it was a start. If you had SD ENG content to stick into an HD news program, this capability allowed you to mix both formats.

Effects and layers

There is an interesting contrast between analog switchers and modern digital implementations. Production switchers used to cascade mix effects, 1 into 2, 2 into 3, etc. Today, all effects are processed on an equal footing, and internal computations match the signals in time, so putting 2 before 1 is not a problem.

What about layers? Early digital implementations from Grass Valley and Abekas offered true layering, where each layer was processed with effects and keys, and subsequent layers could reveal or hide content in lower layers. Today, some switchers can easily conceive and control layers, which is perhaps more intuitive for many productions.

Sophisticated control

We take it for granted that today's complex switchers can control machines. If a moving swoosh is used to reveal a replay, the source must be told to run in sync with the DVE or wipe that is bringing it onto the screen. Similarly, the audio effect must be triggered, and a sequence must be cued on a CG. This capability can be exceedingly complex. It might not be possible without sophisticated control systems.

When all control was done on RS-422, this was difficult. But now that many devices can receive commands over TCP/IP connections, device control is easier.

As Ethernet control becomes more ubiquitous, we can expect even closer ties between switchers and other source devices. This no doubt conflicts with other control strategies, such as newsroom computer systems and production automation, but I suspect it is a fact of life.

John Luff is a broadcast technology consultant.

Send questions and comments