Making Movies: Video & Camcorder Jargon Decoded

Richard Baguley,
special to PC World

With the possible exceptions of nuclear physics and brain surgery, few topics are more jargon-filled than digital video: If you were to join in a conversation with a group of video geeks, you'd be assaulted with terms like "24p" and "HDV." Nobody likes to admit their ignorance, so here's a handy guide to some of the jargon that the camcorder cognoscenti like to throw around. Feel free to use it to bluff your way into the video elite.

16:9: This refers to the aspect ratio of a wide-screen TV image. It's the ratio of the width to the height; so if the image is 16 inches wide, say, it would be 9 inches high. Standard TV programs have an aspect ratio of 4:3. Some camcorders that offer 16:9 recording don't actually record video in 16:9 format. Rather, they capture 4:3 video and chop it off at the top and bottom so that it will fill a wide-screen display. Others (including HDV models) do record true wide-screen video, using an image sensor with a 16:9 aspect ratio.

24p: You'll hear this one a lot if you hang around the film-school cafeteria. Basically, movies on film--as in the stuff that Steven Spielberg and other Serious Directors use--run at 24 frames per second. The video we see on our venerable analog NTSC-format TVs runs at 29.97 frames per second (that odd number is a whole story in and of itself). Consequently, if you want to make a NTSC video that looks like it was shot on film, you need to do some serious processing to convert the video from 29.97 to 24 fps. But if your camcorder records in 24p, it captures 24 frames per second for that authentic "I'm a serious filmmaker who wants to shoot on film, but I can't afford it right now because I'm waiting for DreamWorks to call" look. The "p" refers to the fact that the video is recorded using progressive scanning, as opposed to interlaced scanning (see entries for progressive scan and interlacing, below).

CCD: Charge Coupled Device, a type of image sensor (see CMOS, below).

CMOS: Complimentary Metal Oxide Semiconductor, a type of image sensor used in many camcorders. The more expensive models usually use CCD sensors, which are generally less prone to picking up electrical noise (which might make images look grainy). But these days, the difference between the two types of sensors is small, and many manufacturers are switching to CMOS sensors because they are cheaper to produce.

HDV: High Definition Video. This is a new one. HDV is a standard for camcorders to record high-def video onto a standard MiniDV tape; that's the same type of digital tape that most standard-definition digital camcorders use. "What?" I hear you cry. "How is that possible? How can you fit HD video onto a tape designed for standard definition video?"

Well, by using compression: Video shot in HDV is very heavily compressed so that it takes no more space than standard definition video. If you really want to look cool, raise this point when HDV comes up in conversation, and tell everyone that you refuse to use it, because "real cameramen don't use compressed video." That'll get you a hearty slap on the back from your fellow professionals and several video geek points.

Interlacing:
A scanning mode used to create the illusion of high-image resolution while conserving bandwidth. In order to create the resolution that they wanted, the designers of the NTSC broadcast standard cheated a bit, cutting the TV image into two parts, called fields. One field contains the odd-numbered scan lines of the TV image, while the other contains the even-numbered ones, and the TV displays them alternately.

Because the fields are displayed in rapid succession (one field every 60th of a second to produce one full frame every 30th of a second), the human eye perceives them as one image. This process is called interlacing. Interlacing can produce artifacts when the scanned image contains fast-moving objects. If the object moves in between the frames, or if the camera zooms, you might notice a jittery effect as in the image shown here. (See progressive scan, below.)

NTSC: National Television Systems Committee. In 1953, the NTSC created the TV standard used in the U.S. Due to the way that the NTSC signal is compressed, squeezed, and otherwise generally messed around with before it gets to your TV, many video professionals say that NTSC really stands for "Never Twice the Same Color."

PAL: Phased Alternation Line, the standard for analog TV in the UK and parts of Europe. It's sometimes facetiously referred to as "Pay Another License," a reference to fees for the licenses required to view TV in the UK that fund the British Broadcasting Corporation. You'll occasionally see dealers in the U.S. selling PAL camcorders and other equipment, claiming that it delivers better-quality images. This is a debatable point. PAL does actually have more lines of screen resolution than NTSC: 576 visible horizontal lines instead of NTSC's 525. But even if this is true, you shouldn't buy PAL gear. Most U.S. TVs don't support PAL, so if you used it to shoot your videos you probably wouldn't be able to watch them on your own TV. Some European countries (most notably France) use a slightly different French-developed video standard called SECAM, which roughly translated stands for "Sequential Color With Memory."

Progressive Scan: You'll often see this term associated with DVD players as well as some camcorders. NTSC-broadcast TV images are interlaced, but a progressive-scan camcorder or player processes the image so that all scan lines in a frame are displayed in sequence. When progressive-scan video is shown on a display that supports it, fast movement appears smoother than it does in interlaced video.

Richard Baguley is a PAL freelance writer who lives in an NTSC world, which explains why some people don't understand him. He blogs about camcorders and video at

http://news.yahoo.com/s/pcworld/123201

Copyright © 2005 PC World Communications, Inc.