“We want to add live video to our worship services,” has to be the most common e-mail I receive from churches requesting my design services. It seems that having a projector for song lyrics isn’t enough for a growing number of churches. As they look to the large megachurches for guidance, the desire to emulate the live video cameras and video “roll-ins” (from DVD, VHS or hard drives) is in fashion.
The addition of live camera shots, called IMAG (Image Magnification) is typically not necessary in rooms seating less than 750, as it’s generally easy to see the pastor, music leaders, and other performers. What churches are more in need of is the ability to seamlessly add video clips, animated backgrounds for song lyrics, and computer images in real time.
This desire to add video isn’t new. The reality is that a number of years ago the vast majority of churches realized the value of adding projection for song lyrics, sermon graphics and announcements using Microsoft’s PowerPoint or, more recently, a worship presentation software package, and simply relied upon the simplicity and ease of use of these static text and graphics displays.
In the past, the ability to add video, for many, was limited to the occasional VHS tape or DVD disc. The easiest way to do that was to use the projector to select the computer or video input with the projector’s remote control whenever these infrequent videos were needed. Simple enough, but certainly not elegant.
As churches have become accustomed to this basic technology, the desire to look more like the dominate medium of our society – television – led to the search for better ways to present video and computer images.
Video and PC Signals Don’t Mix
Sure, the projector could show either the PC image or the video source, but
not quickly (hence the conundrum of the blue screen between sources), and certainly
not smoothly. Then a revelation: “dumb down” the PC signal to a
video signal, and an inexpensive video mixer could save the day.
This process, known as scan converting, requires a scan converter, which converts the highresolution PC down to a standard video signal. The only drawback with this method is that the scan conversion process significantly reduces the quality of the original computer image to a much less crisp video-quality image. The upside was that now churches could cut, dissolve and wipe themselves into oblivion with the simple video mixers, and only send a single video cable to the projector.
A video mixer is a device that accepts video signals and uses a frame synchronizer to allow for cuts and dissolves between the sources. Typically less expensive than video switchers, they offer a simple solution when budget overrides high-end resolution.
For churches using broadcast-quality cameras, full video switchers, which include more robust controls on inputs for timing to a blackburst generator, as well as tally lights for cameras, were used.
Churches then began to wonder why the opposite wasn’t possible: why not up-convert the video signal to the level of the computer image? Wouldn’t it mean that a computer mixer would then act the same as the video mixer? Not quite.
The process of up-converting video to a computer resolution is known as scaling and requires, yep, you guessed it, a scaler. A scaler accepts both computer and video inputs and creates a unified output at computer resolution to match the projector’s native resolution.
The single scalers, while allowing for perfect computer images, didn’t allow for the same instant cut and dissolves that the video mixers provided. The reason was that a single scaler can only process one signal smoothly at a time; thus, a video to computer transition was usually limited to freezing the video and then dissolving that frozen video image with the static computer image. It worked, but it wasn’t very polished.
Other scalers tried to minimize this by having the video image fade to black, and then fading the computer image back in from black. To some, this is a better solution, but in my opinion, this is the same as your favorite television show suddenly going to black – you assume that either something went wrong or that it’s time for a commercial.
To provide the same smooth dissolves and cuts that the video mixers and switchers did, a dualscaler technology was invented. These more expensive devices smoothly fade between any two sources, and a few even allow for a graphic to be “luma-keyed” (like the text over a news reporter) over the inputs. These high-resolution devices are currently the best in terms of picture quality, as they send computer signals to match the exact resolution of the projector(s).
As good as these new dual scalers are, they still cannot process the high-end effects, called DVEs (Digital Video Effects) or Chroma Key (removing a color and replacing the image with an overlay, much like the weatherperson on a green screen) like those available on video switchers. For many churches, this isn’t much of an issue, as cuts and dissolves are the two main forms of transitions, but the limitation still exists.
Therefore, it comes down to application: if you use video more than computer images, video mixers or switchers are probably the way to go; but if you use computer images more than videos, the scaler technology is, most likely, better suited for your uses.
Dollar for dollar, scalers are typically more expensive than video mixers, but broadcast video switchers can cost more then even dual scalers. It’s the old axiom that I teach all the time: application drives the technology, which drives the budget. Figure out what you want to do, learn which technology will accomplish that, and then budget to buy (or lease) that technology.
Unfortunately, it’s not uncommon for churches to buy a $99 scan converter at a local electronics retailer, add a video mixer, and expect quality results. Each part of the signal chain matters, so when using video mixers, a good scan converter ($1,000 to $2,000) is necessary. However, with the high-end dual scalers, no other processing gear is necessary, as scaling does all processing inside the unit.
As progress in technology marches on, churches will continue to have more robust controls for playing back all kinds of media formats on their projectors and other displays, and it will only become a clearer and sharper picture as the switchers and scalers continue their meteoric rise in quality.
Anthony Coppedge, CTS, provides consulting to churches, manufacturers,
and dealers. He may be reached at anthony@anthonycoppedge.com.
