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Software Field Monitors, Part 1

May 12, 2008 12:00 PM, By Jan Ozer

One of the coolest product categories in the HDV@Work space is software programs that provide video scopes, a large preview monitor, direct-to-disc recording capabilities (DDR), and other features. In this issue, I'll introduce you to the category of products and illustrate and explain some of their benefits. Next issue, I'll look at two of the more prominent products in the category: Adobe OnLocation CS3 and Divergent Media ScopeBox 2.0.

By way of background, to run these programs, you connect your camcorder to your computer via your FireWire port and click your camcorder into recording mode. Once the video starts previewing in your viewfinder, it gets transferred through the FireWire connection to your computer, where these programs analyze the incoming stream, displaying a preview window, various scopes, and other data on your computer screen.

Scopes and Such

The biggest problem these programs help solve relates to tuning your cameras for optimal exposure. Back in the day, where shooting high-quality video required a $25,000 camera and a budget to match, most videographers lugged various scopes around to ensure proper exposure and also to ensure proper white balancing.

The democratization of video production, delivered courtesy of the DV camcorder, didn't eliminate the problem, but few of the new class of producers could afford this equipment. So most of us either shot in automatic exposure mode or tried using zebra stripes to set exposure. Unfortunately, zebra stripes are a blunt instrument when it comes to fine-tuning exposure settings—especially when viewed in a 2.5in.-or-smaller LCD preview screen. So the biggest problem these programs solve is to deliver scopes on location (assuming that you have a notebook computer, of course).

If you've never worked with a waveform monitor, it's almost impossible to grasp how significant this truly is. So let's take a step back and discuss what a waveform monitor is and how it works. Have a look at Figure 1.

This is a screenshot of OnLocation showing a video of my buddy Gary holding a white-balance card. The Waveform Monitor is on the upper right, while the Automated Quality Monitor, which I'll discuss in the next issue, is on the lower right.

Briefly, the Waveform Monitor displays the light in the scene in waveform mode so you can analyze lighting intensity. Levels are represented in IRE values (for Institute of Radio Engineers, go figure) and shouldn't exceed 100, which is pure white, or fall beneath 7.5, which is pure black. If the signal exceeds these values, the camera simply captures all white or all black in the effected pixels, essentially losing the detail in those pixels.

Note that the horizontal position on the Waveform tracks the horizontal location in the video frame, so the wide, flat area you see on top of the waveform shows the value of the white-balance card that Gary is holding. The IRE values for the white balance card are above 100 IRE, which isn't a problem because I'll remove the card before shooting for real. But, if I shot as is, the text you can see on the card would likely disappear in the captured video, turned pure white by the excessive light.

On the other hand, Gary's face is around 65 IRE, which is too low for a Caucasian face—I'd want those levels to be around 75. In addition, because the values at the bottom of the waveform—which represent the black curtain—are hovering above 7.5 IRE, if I shoot as is, the curtain may appear faded. The clear message is to reduce lights on the background and boost lights on the face (and don't let Gary wear a white shirt), which is a whole lot more data then I'd get from zebra stripes set at 100 IRE or 75 IRE.

© 2008 Penton Media, Inc.