Anamorphic - the process where a “wide” video image (typically in a widescreen format) is compressed or squeezed horizontally to fit a more narrow video display standard but expands to full size when played over a wide video display. Typically used on DVDs where "black bars" are added for 4:3 televisions but disappear when shown on a 16:9 one.

Bitrate - the average number of bits that one second of video or audio data will consume. Higher bitrates mean bigger file size and generally better video or audio quality while lower bitrates means smaller file sizes but worse video or audio quality. As examples, MP3 files typically use 128 kilobits (16 kilobytes) per second, VCDs typically use 1374 kilobits per second, DVDs average about 4500 kilobits per second and "raw" digital video takes up about 25 megabits per second.

Component video - a video system containing three separate color component signals, either red/green/blue (RGB) or chroma/color difference (YCbCr, YPbPr, YUV), in analog or digital form. The MPEG-2 encoding system used by DVD is based on color-difference component digital video. While few televisions have component video inputs, this is by far the best way to connect a DVD player to a TV, as it visibly produces the best picture.

Composite video - an analog video signal in which the luma and chroma components are combined (by frequency multiplexing), along with sync and burst. Also called CVBS. While this type of connection offers the least quality video (compared to component or S-video inputs), almost every TV and VCR manufactured since 1990 has composite video connectors, which are usually colored yellow. Your television or VCR probably has one of these inputs on the front of the appliance (along with red and white plugs for audio) to connect video cameras or game consoles.

CSS - stands for "Content Scrambling System". On DVDs an encryption scheme is used to protect the copyrighted material that resides on a disc by periodically scrambling the data using encryption keys.

Dolby Digital - Dolby's best-known digital system, is used to provide multichannel surround sound in cinemas from 35 mm film and in the home from laser discs, DVDs and digital broadcast, cable, and satellite television.  It enables the transmission and storage of up to five full-range audio channels, plus a low-frequency effects channel (LFE), in less space than is required for one linear PCM-coded channel on a compact disc.  Compressed at roughly a 12:1 ratio.

DTS - stands for "Digital Theatre Sound", one of the two major types of audio contained on DVDs. DTS is a multichannel audio compression format similar to Dolby Digital. DTS differs from Dolby Digital in that it generally uses higher data rates (and therefore less compression) and many have the opinion that DTS is better quality. DTS can only be on a DVD-video disc if accompanied by a Dolby Digital or PCM track (for North America) or mpeg audio and LPCM (Europe) to ensure compatibility, because DVD players are only required to decode those standards in those regions.  Compressed at roughly a 3:1 ratio.

DVD - stands for either "Digital Versatile Disc" or "Digital Video Disc" depending on who you ask. DVDs look like, but are a different format from, compact discs. Because of this, normal CD players or CD-ROM drives cannot read (or write to) DVD discs. DVDs that contain video do so in the MPEG-2 compression format, as opposed to VCDs which use MPEG-1.

DVI - Stands for "Digital Video Interface", the newest (and best) type of connector for video sources. Typically used to connect computer video cards to digital LCD displays or high-end cable boxes to HDTVs. Comes in three flavors: DVI-D (digital), DVI-A (analog) and DVI-I (integrated digital/analog)

Letterbox - because televisions are essentially square and because movies are essentially rectangles, most movies require alteration to be shown on a TV. The preferred method of doing this is letterboxing, where black mattes are added to the top and bottom of the screen. This reduces the overall picture size but allows the film to retain its original 1.85:1 or 2.35:1 ratio while being shown on a 1.33:1 television. Please see Pan and Scan for more information as to why the "black bars" are the only way to watch movies on TV.

MPEG-1 - An ISO standard for medium quality and medium bitrate video and audio compression. It allows video to be compressed by the ratios in the range of 50:1 to 100:1, depending on image sequence type (i.e. action movies vs.  and desired quality. The encoded data rate is targeted at 1.5Mb/s - this was a reasonable transfer rate of a double-speed CD-ROM player (including audio and video). VHS-quality playback is expected from this level of compression.  MPEG-1 is used in encoding video for VCD as well as just about every MPEG video file played back on personal computers.

MPEG-2 - An ISO standard similar to MPEG-1 but allows for much higher bitrates (and therefore much higher quality).  Also includes the ability to use Dolby Digital and\or DTS stereo audio (among others).  Currently, MPEG-2 is the standard format for DVD, SVCD and digital broadcast.  

NTSC - stands for "National Television Standards Committee". The NTSC is responsible for setting television and video standards in the United States, Canada, the Caribbean and Japan (in Europe and other parts of the world, the dominant television standards are PAL and SECAM). The NTSC standard for television defines a composite video signal with a refresh rate of 60 fields (half-frames interlaced) per second. Each frame contains 525 lines and can contain 16 million different colors. The resolution of an NTSC VCD is 352x240 pixels, an NTSC SVCD is 480x480, and an NTSC full D1 DVD is 704 or 720 x 480.

PAL - stands for "Phase Alternating Line" and is the dominant television standard in Europe. PAL delivers 625 lines at 50 fields (half-frames interlaced) per second. The resolution of a PAL VCD is 352x288 pixels, a PAL SVCD is 480x576, and a PAL full D1 DVD is 704 or 720 x 576.

Pan and Scan - because televisions are essentially square and because movies are essentially rectangles, most movies require alteration to be shown on a TV.  Most true movie fans prefer letterboxing, where black bars are added to the top and bottom on the screen.  This makes the picture smaller overall, but preserves the ratio the movie was originally filmed in.  The other option is to crop parts of the picture by "panning and scanning" the original film.  This has the benefit of filling up the entire screen, but up to 50% of the original picture can be lost this way.  Imagine having an 8x10" print but only a 5x7" picture frame.  One way to frame it would be to have the picture reduced so that it will fit the frame (letterboxing).  The other way would be to cut the picture to fit the frame (pan and scan).  

Movies that have been "panned and scanned" tend to lose some of the flavor of the original film.  For example, one common pan and scan trick involves showing only the actor that is currently speaking then panning to another actor when he or she begins speaking.  In a famous scene from the movie A Few Good Men, Tom Cruise, Jack Nicholson and Demi Moore have a conversation while riding in a Jeep.  In the original film (and the widescreen DVD), the camera is mounted on the front of the Jeep and does not move throughout the scene.  In the "pan and scan" version there is not enough room to display this scene as intended, so the camera moves to each actor as he or she speaks.  Much of teh original flavor is thus lost.  The process of panning and scanning a movie can also lead to hilarious (unintended) blunders, such as Bruce Willis having a conversation with no one in the pan and scan version of Die Hard or Luke Skywalker saying "look, there's sand people!" while looking through his binoculars when no sand people are on screen in the pan and scan version of Star Wars (the sand people he's talking about were clipped).  Note that because almost every movie made before 1950 shares the same 4:3 ratio as TV, classics like Casablanca or Gone With The Wind are not subject to this abuse.                  

PCM - stands for "Pulse Code Modulation". An uncompressed, digitally coded representation of an analog signal. The waveform is sampled at regular intervals and a series of pulses in coded form (usually quantized) are generated to represent the amplitude. Used on some DVDs, on audio CDs and is the native Windows sound format.

Ratio - Most televisions are nearly square. The ratio of width to height is, by standard, 1.33 inches wide to 1 inches high, commonly abbreviated as 1.33:1 or 4:3. When television first began to become a standardized product, this ratio was chosen out of convenience because at the time movies were filmed in the same 4:3 ratio. If you know your history, you'll know that Hollywood was initially scared to death of TV, thinking people would stay at home instead of going to the theatre to see movies. Because of this, the 1950s became known as the "Gadget decade" in Hollywood history. Many new tricks were tried to lure people out of their homes. Most, like 3-D and "Smell-O-Vision" did not last. In fact, one of the only tricks that did last were larger screens. Movies began to be filmed in new ratios, like 1:85:1 and 2.35:1. This made the pictures much larger, but also more rectangular. This created problems when movies shot in these ratios were shown on TV (and eventually distributed via VHS tape and DVD). How could Hollywood show a movie shot in a 2.35:1 ratio (also called 16:9 or just "widescreen") be shown on a 4:3 TV screen? The answer was letterboxing and pan and scan. Because pan and scan alters the original camerawork and possibly the "vision" of the director, there are now many movements dedicated to retaining the Original Aspect Ratio (OAR) of the film via letterboxing  instead of panning and scanning. Several websites are dedicated to this as well as many famous movie critics like Roger Ebert.     

RCE DVDs - stands for "Region Coding Enhanced" DVDs. These DVDs attempt to detect whether your DVD player is "region-free" and if found to be so, will insert the following message on your TV screen: THIS DVD PLAYER MAY HAVE BEEN ALTERED AND IS UNABLE TO PLAY THIS DISC.  THERE IS NOTHING WRONG WITH THIS DISC.  DVD PLAYERS AND DISCS ARE DESIGNED TO WORK IN CERTAIN REGIONS.  THIS DISC IS NOT COMPATIBLE WITH THIS PLAYER. PLEASE CONTACT YOUR LOCAL RETAILER OR PLAYER MANUFACTURER FOR ADDITIONAL INFORMATION. WE APOLOGIZE FOR ANY INCONVENIENCE and will refuse to play the disc. RCE discs are typically only a problem for owners of "region-free" or "multi-region" DVD players or old "pre-RCE" DVD players. Click here for more information about RCE. 

Region - Hollywood's system of controlling (staggering) DVD releases throughout the world. This is done to ensure that people in one country cannot obtain a DVD disc of a movie before the movie is released theatrically in their country. All DVD players and all DVD discs are required by the CSS licensing agreement to be bound to just one region. Here are the regions as defined by Hollywood:

Region 1 - North America
Region 2 - Europe, Japan, the Middle East and South Africa
Region 3 - Southeast Asia (including Singapore, Indonesia, Thailand, etc.)
Region 4 - Australia and South America (including Mexico)
Region 5 - Russia, Africa (except South Africa) and any part of Asia not listed above (including India)
Region 6 - China
Region 7 - not used presently
Region 8 - Used on aircraft and ships  

SECAM - stands for Séquential Couleur Avec Mémoire/Sequential Color with Memory. A composite color standard similar to PAL, but currently used as a transmission standard only in France and a handful of other countries, mostly former French colonies. Video is produced using the 625/50 PAL standard and is then transcoded to SECAM by the player or transmitter.

SVCD - stands for "Super Video Compact Disc". Similar to a VCD in that SVCDs are compact discs, but differs from them in that they use MPEG-2 encoding like DVDs and can also include 2 different audio tracks and up to 4 types of subtitles. A SVCD can hold from 35-60 minutes of programming, depending on the encoding quality as well as how many audio tracks and subtitle tracks are included on the disc.   

S-Video - A method of sending video down a multi-wire cable. S-Video sends the color and brightness signals separately down the cable, which leads to a better picture quality than composite video, but less quality than component video.

VCD - stands for "Video Compact Disc". Very popular in Asia but just about nowhere else, VCDs are standard compact discs with MPEG-1 encoded movies on them. Because CDs only allow for about an hour per disc in the MPEG-1 format, most VCD movies are two disc sets. It is possible to have VCDs with menus and chapters (like a DVD) or VCDs that contain only pictures and sound (like Picture CDs). The picture quality of VCDs varies widely but is roughly comparable with VHS tape.