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11.10.2006
A Multi-Definition Production Switcher
Production switchers continue to evolve into ever more powerful tools for the control room. Traditionally, switchers were live layering devices allowing operators to select sources, add various layers of keying and perform wipe and dissolve transitions between them. Now, production switchers have added the functionality of high-end digital video effects (DVEs), still stores, logo generators, color correctors, device controllers and even automation systems. Choosing the right brand, switcher size and optimal feature set has become a complex task.

The most basic starting point is to choose the number of inputs required. Count the inputs that need direct access during a production, remembering that signals from devices like character generators count as two—one for the key and one for the fill. Having a large number of inputs is usually a sign that you have a large investment in your production facility and will probably require a more sophisticated switcher. Generally speaking, smaller switchers have fewer inputs and larger switchers have more.

M/Es
The next decision point is usually how many effects banks, or M/Es, the switcher should have. An M/E is very much like a self-contained switcher, producing a composite image output. M/Es can directly cascade into subsequent M/Es. Switchers on the market today range from one to four M/Es.

There are several reasons why a production may need multiple M/Es:
  • Complex effects: If more layering is needed than is available in one M/E, effects can be built by cascading one M/E into another. How much can be done in one M/E can vary significantly between switcher brands.
  • Back to back effects: Consider the flow of the production and the most complex scene that must be followed by another complex scene. Changing the production requirements such that an uncomplicated scene like a simple camera shot always follows a complex scene can dramatically reduce the number of M/Es required.
  • Operational ease of use: Although initially intimidating, a large switcher can actually be easier to use than a small switcher. With a large switcher, M/E banks can be dedicated before the start of the show to certain segments such as two box interviews, weather chroma keys and server clips. With a small switcher, the operator must rapidly recall these effects from memories, check them, possibly adjust them and then take the effect to air.

    A two M/E switcher has a fundamental operational advantage over a one M/E switcher that goes beyond simple effects capability. With a two M/E switcher the operator can switch simple segments of the show on the bottom M/E while recalling a complex scene in the upper M/E. When the complex scene is previewed and known to be correct, the operator then takes the upper M/E to air. Eventually, the operator reverts to switching the next simple part of the show on the lower M/E, freeing the upper M/E to be preset to the next complex scene.

    In a one M/E switcher, this ping-pong rhythm isn’t possible. Complex scenes must be recalled directly to air on top of whatever is currently set on the one and only M/E. This reduced operational flexibility can lead to on-air mistakes, although skilled technical directors take the complexity of the show they can produce on a single M/E switcher as a point of pride.

    A compromise between cost and production flexibility is to purchase a switcher with a very simple bottom M/E that only cuts, dissolves and linear keys. This is called a 0.5 or half M/E. In the above example, a 1.5 M/E switcher offers “ping-pong” operation at a lower cost than a full 2 M/E switcher.
OPTIONS
Once the appropriate switcher size has been determined, it is useful to go through the many optional features available. Popular major options include:
  • DVE and warp channels: Here, again consider the most complex effects that are needed back to back to determine the number of channels required per M/E. Making the DVE effect capability the same in all M/Es further adds operational flexibility during a production. Think about the special effects that may be required during the life of the switcher—there may not be an upgrade path with some brands.
  • Animation stores: Consider what effects you might do outside the switcher in external devices such as CGs and video servers. Then consider what it would mean if you did them inside the switcher. Consider the workflow as to how you will get your animation files into the switcher. Consider the benefit of an onboard hard drive that can permanently store commonly used graphics and animations as well as offer dramatically higher capacity than systems that have volatile RAM memory.
  • RGB color correctors and proc amps: Whether employed for dramatic effect, corrections for lighting errors, composite analog errors or pre-correction for on-set monitors, color correctors and proc amps can really add an element of polish to a production. Does the switcher you are considering offer the ability to apply these corrections to the inputs, the M/Es and/or the aux bus outputs?
  • Auxiliary bus keying: Auxiliary bus keying can be employed to add mixing and keying to auxiliary bus outputs. This is a handy feature wherever you need an extra mix/key function. For example, feeding on-set monitors, split feeds on the output of the switcher and pre-keying on an input to the switcher.
MULTIPLE DEFINITIONS
Once the size and effects capability of the switcher have been determined, next consider the overall production environment in which the multi-definition switcher will be placed. It is important to know the number of different SD/HD signals that will need to be converted from one video format to another. Conversion to the desired HD production format can be handled in three ways—at the source, in the facility router or at the production switcher itself. One of these solutions will make the most sense for your application.

If the switcher is the only multi-def destination, as in a truck, conversion in the switcher may be best. Most current multi-def switchers offer conversion tied into the M/Es. Some allow the converters to float between M/Es and to the aux bus outputs, and some don’t. Some offer a fixed number of converters per M/E, and some allow the user to choose. Typically, the more flexible the system, the fewer converters you will need to ultimately invest in.

At some point in the selection process, budgets often become tighter than expected. One way to save money is through operational efficiency. Device control directly from the switcher can produce tighter productions with a smaller crew. Some production switchers can now control external tape machines, video servers, audio servers, audio mixers, routers, robotic cameras and even character generators.

A hot topic today, often considered to be the future of live production, involves production control systems. These systems are capable of putting the operation of all your control room devices on a single set of touch screen displays and dramatically simplifying the execution of a complex production.

Advancing through a production can be as simple as tapping the spacebar of a computer keyboard to move to the next look. Some systems even provide a link to newsroom editorial systems such as iNEWS or ENPS. This link allows a news production to be built, specifying effects, server clips, audio levels, robotic camera positions and other devices in the newsroom system, and then driven through the production control system to air. Buying a switcher that is capable of adding a production control system can be a very wise move.

If the facility has a requirement for multiple production switchers of different sizes, consider whether the brand offers a family broad enough to meet all of your needs. If all of the switchers share the same chassis and user interface, there are significant savings in training and spare parts interchangeability.

One final “gotcha” in production switchers is after-sale costs. Be sure to calculate the total cost of ownership for the expected life of the product that you are considering buying. Warranties can range anywhere from one to three years, extended warranty charges vary widely and access to software upgrades and basic tech support can range from free to close to 10% of the original list price every year thereafter. Does the manufacturer have an upgrade policy for moving to a larger switcher, making feature additions, or moving from SD to HD?

Switchers are a large, critical, long-term investment and it pays to make the right decision.

David Ross is CEO of Ross Video (www.rossvideo.com).


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