| If you're interested in three-dimensional design, capturing video from your VCR or Television, using a monitor as a TV or recording a computer-generated slide show on DVD, you'll need a video board that can handle these chores.
Some expensive video boards can handle one or more of these chores along with a regular display, but you'll often have to add an auxiliary video adapter to get the work done.
Rendering lifelike three-dimensional objects requires your computer to perform an incredible number of complex mathematical calculations. This is especially true if you're using design software that gives you control over light sources, shadows and surface textures. You'll need even more horsepower if you want to be able to rotate your design on the screen or take a "tour" of a virtual building you've created. For this kind of work, you may want to buy a video adapter with an accelerator designed specifically for 3-D rendering. This is particularly important if you want to get maximum performance out of a new Pentium or AMD chip.
Since your monitor looks a lot like a TV set, you may wonder why you can't use it like a TV. The reason is that television signals and the signals your video board produces aren't compatible. But if you're willing to spend some time and money, you can mate the two, and there are good reasons for doing so.
Let's say you've developed a terrific multimedia presentation on your computer using PowerPoint, Freelance or Macromedia Director. You'd like to share it with others, but not everyone has a computer like yours. If you can record the presentation on a CD or DVD, virtually anyone can see it. Likewise, you may want to import some pictures from a video tape or a media stick into a presentation, use a TV camera to snap photos for company ID cards or use your computer to fool around with images from the digital tapes you made on your last vacation.
Your video board and monitor use RGB (red, green and blue) signal systems. Unfortunately, television sets, VCRs and other consumer video equipment use a composite signal compatible with international broadcast video standards. Your computer and TV don't agree on how to handle color, how many scan lines to produce on the screen, or how many times to redraw the screen every second. On top of that, they use different kinds of hardware to transfer signals from one device to another.
There are two dominant video broadcast standards: The NTSC (National Television Standards Committee) standard prevails in the Western hemisphere and in Japan . In most of Europe and Asia , the PAL (Phase Alternating Line) standard is the rule. That's why you can't use TVs or VCRs made for use in the United States when you travel to Europe , and vice versa.
If you want to get standard broadcast video into or out of your computer, you'll need a special-purpose adapter that can convert one type of signal to another.
These boards allow you to capture signals from a TV camera, VCR or similar source. Less expensive boards will allow you to "freeze" a frame and record it in a standard graphics file format. Expensive video processing boards will actually record the video digitally.
Note that a video capture board won't necessarily turn your monitor into a TV set, because most boards don't have TV tuners. You can buy capture boards that will handle TV signals and display "Baywatch" in a window on your screen. In fact, some multimedia PCs designed for the mass market have TV tuners built in. But if all you want to do is watch TV while you work, you'll get a better picture for less money by buying a small television set.
These gadgets convert your system's video output to a signal compatible with NTSC or PAL equipment, such as TV sets and VCRs. You can use a television set as a monitor (which is great for presentations before large groups) or use a VCR to record what you see on your monitor.
This job doesn't necessarily require an internal circuit card. You can buy external converters that plug into your computer's monitor port on one side and into a TV or VCR on the other. These are particularly popular with laptop computer users who want to take presentations on the road.
Just remember that there are limits to the conversion. Because TV sets can't produce as many lines on the screen as your monitor, you'll generally be limited to using a 800 x 600 resolution.
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