I know you’ve seen the numbers, those little incrementing digits that appear on the video screen now and then — sometimes by accident, some-times on purpose. You’ve also run across them on many types of professional gear, including editing systems, videotape recorders, media servers, audio boards and even lighting consoles.
What the heck is genlock … (and where can I buy one)?
I actually overheard that very question at a recent training session and thought that I might be able to shed some light on the mystery. For us propeller-heads in the video world, we’ve grown up with the knowledge of “genlock,” so it’s not a foreign concept to us. But for those in the lighting and projection realm who are now dealing with video equipment on an ever-increasing basis, the mysterious genlock connector might need some clarification.
Did you happen to see a snowman asking a group of Democratic presidential candidates about global warming? If you did, then you were watching the CNN/YouTube Democratic Presidential Debate. I had the opportunity to work on the event, but this time I was the lighting programmer, and I was not involved in the video production. But it’s interesting to note how a production changes when there is video in the mix.
Working with Mixed Media and Mixed Resolutions
So, you’ve just returned from a major industry trade show, and the LED exhibits were stunningly beautiful — simply breathtaking in their creativity. So, fresh with ideas, off you went back to the shop, slammed together some content, set up your company’s LED wall, sized up the video through your scaler — and voila! Third-generation VHS dubs look better than this. What gives? “Them trade show guys must know something,” I hear you mutter.
Well, in fact, they do.
Video didn’t spring fully-formed from a media server…
[For those of us who are new to the video world by way of lighting, the entire history of the development of media servers, non-linear editing, and all the tools of the video trade are as much of a mystery as the plethora of video formats. To those of you who are new to the lighting world by way of the video world, the entire lack of knowledge about these things from the lighting side is as much of a mystery as DMX512. In this article, Paul Berliner bridges the gap for us. – ed.]
Back in the infancy of the computer industry, circa 1965, a young Mr. Gordon Moore (a co-founder of Intel) had a most prescient thought in an article he authored for Electronics Magazine — the number of transistors on a silicon chip will double approximately every two years, ad infinitum. Since that moment, his prediction has entered the vernacular as “Moore’s Law,” and it’s been pretty darn accurate to date. It’s also been a very good representation of the cycle of change in which we operate today in the video and entertainment industries. The keyword is “change.”
It’s a fair question: Do two doublestacked 5K projectors equal the brightness of one 10K projector?
The issue, it seems, has been a hot topic among projection designers, but lately it has become more prominent since the proliferation of projection, double stacking and edge blending software. Last June, when High End Systems debuted their Collage Generator, which combines up to eight DL.2 digital projectors and creates one large edge-blended image, the question became even more complicated. What is the equivalent brightness of four edgeblended 5K projectors?
The stage is set, the lights go up, the speaker walks out on stage, and the video screen is black. The producer begins yelling at the technical director, and the TD starts yelling at everyone. It’s a demonstration of what flows, and in which direction. It’s also a reminder that, as a camera operator or engineer, you are at the bottom of the hill on which it all flows. Assuming we remembered to remove the lens cover, there are many other pitfalls we would like to avoid. But what other kinds of problems could we have? By understanding a very basic signal flow through the camera, we can protect ourselves from doing something foolish and, more importantly, help us recover quickly when we have already done something foolish.
Projectors are pretty simple. The zoomies go in, the zoomies go out, voila, pretty pictures on the wall—not!
While on the surface it may seem that simple, it can be a rather complex evolution to get from input to output on a video projector. Every manufacturer has unique methodology for accomplishing this. We will look at a basic overview of signal flow through a projector and some of the other key components that make projectors work.
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I sat in on a product demonstration for a projector the other day. While the projector was impressive in terms of brightness, noise level, and ease of set up and operation, I was not impressed with the image. It seemed a bit fuzzy. The material on-screen was a rather generic slide show, and the projector had been set up and focused properly. Then I realized what the problem was. It wasn’t the content or the projector, but the fact that the projector and computer were at different screen resolutions. I mentioned this to the rep, who very quickly reset his laptop so that they were matched and the image was improved dramatically. It was a pixel for pixel match to what the computer was putting out.
So you set up your rig and the projector tells you that no signal is detected. Better to fail now than in the middle of the event. You check your source selections; they’re good. You check your outputs; they’re good. You cable test the lines; they’re good. You realize you are trying to send HD-SDI down a 350-foot run of regular RG-59. That could be the problem. The variety of video signals we work with today provide us with unlimited opportunities for Mr. Murphy to rear his ugly head and remind us how much he really doesn’t like us.
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When we’re deciding on a projector and screen (or screen placement), the question that always comes up is, “Will it be bright enough?”
Lots of folks think that they can just get a brighter projector and that will solve their problems, but it ain’t always that simple. The more common problem encountered when we’re trying to project in a well-lit space is the contrast — or lack thereof. No matter how many lumens the projector outputs, if there is too much ambient light we will have a poor image.