Whether you’re a professional videomaker or
a weekend hobbyist, your video arsenal may be incomplete if you’re not using a personal
computer (PC) in your video productions. Your PC can digitize images in glorious color,
and even overlay computer generated graphics or titles onto your video footage.
Unfortunately, your computer didn’t come with everything you need to perform these
tasks–you need to outfit it with the necessary hardware. This hardware includes the
digitizer, a device which allows your computer to capture and process video images.
Video Capture Boards
A computer stores all information–be it last year’s
tax returns or data that describes an image–as numbers. In the case of the latter, you need a
video adapter to turn these numbers back into a picture. We use several different kinds of
video adapters in desktop video production.
The most popular video adapters found in
today’s IBM-compatible PCs are SVGA graphics adapters. An SVGA board can reproduce
photographically accurate color, known in the computer world as 24-bit color. The SVGA adapter
often comes installed when you buy a PC. Macintosh computers come equipped with similar
Unfortunately, these boards alone are useless for video production.
To use your personal computer for video production, you need a way to input a standard NTSC
video signal into the computer and a way to get that video back out to tape.
The most common
way to input video into your computer is through the use of a video capture board, often
referred to as a digitizer or frame grabber. To go the other way, an “encoder” records the
PC’s output to videotape. The encoder may be an internal circuit board or an external device.
There are several video capture/encoder boards available that do both tasks. The proper
hardware for you depends on your needs, purposes and budget.
Video capture boards come in
two major varieties–motion capture and still-frame capture. Motion capture boards have the
processing and memory required to digitize a moving stream of video; still-frame capture boards
can digitize only a single frame of video at a time. Expect to pay under a thousand dollars for
a good quality video capture board capable of digitizing still frames only.
recently, most motion capture boards in that price range recorded “video in a window” instead
of full-screen images. These boards are fine for computer-based multimedia use, but not for
good quality video production purposes. Today, full-motion video cards are plummeting in
price–see Videomaker’s annual Desktop Video Buyer’s Guide in the March issue for full
The video hardware is half the tools you need. One or more software packages will
be necessary for manipulating your images.
The best way to select the proper
hardware/software combination is to talk to other video professionals to see what they’re using.
Find out how easy the software is to learn, how many layers of menus you need to navigate
through to perform common operations and how well it suits the unique needs of videomaking.
Ask how the publisher supports the software. Is help available through commercial computer
services like CompuServe or America OnLine? Does the publisher offer 24-hour telephone
Desktop Video Applications
The major uses for still images in
video production are image processing (or retouching), graphics keying and titling.
Image processing is one of the most useful capabilities of video graphics boards. Image
processing refers to the process of taking an image and electronically retouching it for a
variety of needs.
Graphics keying and titling are similar procedures. Both processes
allow you to replace portions of your video with computer generated electronic images. In
graphics keying, you can add elements to moving video footage. Titling is the superimposing
of words onto the screen.
Manipulating still images to
create new visuals is one of the most fun (if not devious) things a video digitizer allows you
to do. Image processing software lets you combine pieces of several different images into one.
It also allows you to change the appearance of your subject.
One project I recently
completed for a corporate client needed to show the client’s new corporate headquarters.
Unfortunately, there was no sign on the front of the building.
The only way to complete
the scene was to make a composite image–done by digitizing a photograph of the sign from
another facility and pasting it to a second image of the new building. Since the script called
for an establishing shot, a still frame worked fine for the scene. Tweaking the photograph in
a computer cost much less than any other solution would have.
Another example of a cheap
digitizer fix comes from a training video we produced for a medical equipment manufacturer.
The script called for a shot of a toggle switch in the “on” position.
viewing a rough cut of the program, the client wanted to show the switch in the “off” position.
To avoid the expense of a full day’s videotaping, we digitized a still image of the equipment
control panel. Next, we digitally cut out the switch, turned it upside down, and pasted it back
Finally, we used a “blend” tool to smooth out the rough edges. In less than
half an hour, we completed the entire shot.
But the uses of a digitizer for image processing
don’t end with the practical. For comedic effect, image processing gives bald people hair and
makes hairy people look bald. Want to put a friend’s face on Mt. Rushmore or hover a UFO
menacingly over someone’s house? No problem–you just digitize the necessary images and combine
them in the computer.
Earlier we talked about image processing as a
way to create composite images. Some video adapter cards can genlock (or synchronize) to
incoming video signals, which will allow you to mix the card’s output with the video footage.
If your capture card supports the genlock feature, you will be able to superimpose
computer-generated images over your video footage. Video professionals call this feature
keying. A pre-recorded video signal from tape or a live camera signal can be used for keying.
If you key over a videotape signal, you may need a time base corrector to get perfect
A common use for keying is to put a graphic over the shoulder of an
anchorperson during a news program. In the event you’re creating a news or news magazine-style
show, here’s how it’s done.
First you need to create a graphic, usually in a paint package
or other graphics manipulation software. This takes a bit of planning, especially in choosing
colors and placement of the graphic. The genlock allows you to specify a certain color–the
key color–that will become transparent. It’s easiest to just set this to your background
color, and be careful to not use this shade in your graphic. If you do, the video signal will
appear in the middle of your graphic.
If you’re keying the graphic over the right
shoulder of the news reporter, your computer graphic must be in the upper right corner of the
screen. When placing the graphic, keep in mind that the genlock will cut off the outermost
edges of your computer screen.
Now, turn on the capture board’s
genlock function and run your video signal through it. Your output will be a combination of
the video footage–which can be coming from tape or directly from your camera–and the
Perhaps the most common use for the genlock
feature is to key titles over your footage. The technique is basically the same as in our news
anchor example, only you’re using text instead of a graphic. And though there’s no software
specifically designed to create news-style inset boxes, you have many dedicated titling
software packages to choose from.
When selecting the typeface for your text, remember
that recording out to NTSC will have a definite negative effect on the quality of your
graphics (see last month’s Desktop Video column for the full scoop). For best results, stick to
bold, large letters with lightly saturated colors. Use drop shadows and borders to increase
Choose the type color to complement the footage you are using. Black letters
might look great when keyed over a picture of a sandy beach, but black letters over a night
sky wouldn’t be legible.
If you watch professional broadcasts, you will notice that many
of them use white or yellow letters with black drop shadows. That’s because those color
combinations work best.
One area a digitizer can really shine is in creating backgrounds for text. A static blue background is sadly overused in
corporate and industrial video. Why so many videomakers default to it is a mystery, especially
when the alternatives are so easy to create.
If you open your eyes and look around, you can
find hundreds of abstract, interesting visuals that would be perfect backgrounds when you have
to put text into your videos. Record them onto tape wherever you see them, and you can
digitize them into your computer at a later time.
Or, you can round up various materials
and digitize them all at once. Set your camera on a tripod, engage manual focus and manual
exposure and play around. Look for items with interesting textures, such as metal, wood and
rock. Purposely blurring the focus, especially in close-up, will give a wide variety of
useful backgrounds. Experiment with lighting as well–casting light at a low angle across a
textured surface will really bring out its depth. Sometimes a “flatter” look makes for a
background more conducive to legible text overlays.
Combine those interesting patterns
with the capabilities of your personal computer, and you can create an infinite number of
backgrounds. With the right software, you can tweak, distort and replicate any texture or
surface you digitize.
Here are a few suggestions to get you started:
focus slightly soft, grab a freeze frame of the inside of an empty egg carton. Since the egg
carton is rectangular, a full shot of half the egg carton will only fill about the top quarter
of the screen. Since an egg carton has a strong 3-dimensional look to it, you may want to
experiment with your lighting.
Use your software’s cut and paste function to copy the egg
carton so it fills the entire screen. Experiment using your software’s blend or fill tools to
soften the edges between the pasted areas.
The end result will be a series of geometric
shapes filling up your screen. You would use this image as a background for text.
You could then use a transparency tool to add a colored tint to the picture. You might use a
different color background for each section of your video program, or one color for your
opening credits and another for your closing.
Another great way to get interesting backgrounds for your titles is to grab a still frame from your
video footage and process it. If your video is about your beach vacation, grab a still frame from a wide shot of a beach.
Now you can go in and adjust or eliminate the colors, alter the contrast, posterize the image, turn it into small mosaic blocks,
combine it with another image…the only limit is your imagination.
Did you ever notice all the colors in an oil slick on water?
Try adding a few drops of oil to a tray of water. Move your lights around to get different effects, and digitize the results.
With a digitizer, your PC is a wonderful tool for creating video graphics.
It’s extremely versatile, able to create just about anything you can dream up. When applied to altering images or
overlaying text and graphics, your computer can really set your videos apart from the norm.
David Felder is a writer/producer with Ryan Consulting in Rockaway, NJ.