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DVD Glossary and Terminology

 

DVD Region Code Information

Region Codes Enhanced
Legal Concerns
Standalone DVD Player
Computer DVD Drives
Software DVD Drives
DVD Disks
NTSC, PAL/SECAM

 

DVD Glossary and Terminology

4:2:0 - The component digital video format used by DVD, where there is one Cb sample and one Cr sample for every four Y samples (i.e., 1 pixel in a 2 x 2 grid). 2:1 horizontal downsampling and 2:1 vertical downsampling. Cb and Cr are sampled on every other line, in between the scan lines, with one set of chroma samples for each two luma samples on a line. This amounts to a subsampling of chroma by a factor of two compared to luma (and by a factor of four for a single Cb or Cr component).

720p - 720 lines of progressive video (720 lines per frame). Higher definition than standard DVD (480i or 480p). 720p60 refers to 60 frames per second; 720p30 refers to 30 frames per second; and 720p24 refers to 24 frames per second (film source). Usually refers to 1280 x 720 resolution in 1.78 aspect ratio.

8/16 modulation - The form of modulation block code used by DVD to store channel data on the disc. See modulation.

Angle - In DVD-Video, a specific view of a scene, usually recorded from a certain camera angle. Different angles can be chosen while viewing the scene.

Apocryphal - Of questionable authorship or authenticity. Erroneous or fictitious. The author of DVD Demystified is fond of saying that the oft-cited 133-minute limit of DVD-Video is apocryphal.

Artifact - An unnatural effect not present in the original video or audio, produced by an external agent or action. Artifacts can be caused by many factors, including digital compression, film-to-video transfer, transmission errors, data readout errors, electrical interference, analog signal noise, and analog signal crosstalk. Most artifacts attributed to the digital compression of DVD are in fact from other sources. Digital compression artifacts will always occur in the same place and in the same way. Possible MPEG artifacts are mosquitoes, blocking, and video noise.

Aspect ratio - The width-to-height ratio of an image. A 4:3 aspect ratio means the horizontal size is a third again wider than the vertical size. Standard television ratio is 4:3 (or 1.33:1). Widescreen DVD and HTDV aspect ratio is 16:9 (or 1.78:1). Common film aspect ratios are 1.85:1 and 2.35:1. Aspect ratios normalized to a height of 1 are often abbreviated by leaving off the :1.

ASV (Audio Still Video) - A still picture on a DVD-Audio disc.

ASVOBS - Audio Still Video Object Set.

ATAPI - Advanced Technology Attachment (ATA) Packet Interface. An interface between a computer and its internal peripherals such as DVD-ROM drives. ATAPI provides the command set for controlling devices connected via an IDE interface. ATAPI is part of the Enhanced IDE (E-IDE) interface, also known as ATA-2. ATAPI was extended for use in DVD-ROM drives by the SFF 8090 specification.

ATV - Advanced television. TV with significantly better video and audio than standard TV. Sometimes used interchangeably with HDTV, but more accurately encompasses any improved television system, including those beyond HDTV. Also sometimes used interchangeably with the final recommended standard of the ATSC, which is more correctly called DTV.

Authoring - For DVD-Video, authoring refers to the process of designing, creating, collecting, formatting, and encoding material. For DVD-ROM, authoring usually refers to using a specialized program to produce multimedia software.

autoplay (or automatic playback) - A feature of DVD players which automatically begins playback of a disc if so encoded.

BCA - Burst cutting area. A circular section near the center of a DVD disc where ID codes and manufacturing information can be inscribed in bar-code format.

Block - In video encoding, an 8 x 8 matrix of pixels or DCT values representing a small chunk of luma or chroma. In DVD MPEG-2 video, a macroblock is made up of 6 blocks: 4 luma and 2 chroma.

 Blue-ray - also known as Blu-ray Disc (BD), is the name of a next-generation optical disc format jointly developed by the Blu-ray Disc Association (BDA), a group of the world's leading consumer electronics, personal computer and media manufacturers (including Apple, Dell, Hitachi, HP, JVC, LG, Mitsubishi, Panasonic, Pioneer, Philips, Samsung, Sharp, Sony, TDK and Thomson). The format was developed to enable recording, rewriting and playback of high-definition video (HD), as well as storing large amounts of data. The format offers more than five times the storage capacity of traditional DVDs and can hold up to 25GB on a single-layer disc and 50GB on a dual-layer disc. This extra capacity combined with the use of advanced video and audio codecs will offer consumers an unprecedented HD experience.

Caption - A textual representation of the audio information in a video program. Captions are usually intended for the hearing impaired, and therefore include additional text to identify the person speaking, offscreen sounds, and so on.

CD-Plus - A type of Enhanced CD format using stamped multisession technology.

CD-R - An extension of the CD format allowing data to be recorded once on a disc by using dye-sublimation technology.

CD-ROM XA - CD-ROM extended architecture. A hybrid version of CD allowing interleaved audio and video.

CD-ROM - Compact disc read-only memory. An extension of the Compact disc digital audio (CD-DA) format that allows computer data to be stored in digital format. Defined by the Yellow Book standard.

CDV - A combination of laserdisc and CD which places a section of CD-format audio on the beginning of the disc and a section of laserdisc-format video on the remainder of the disc.

cDVD - DVD-Video content stored on a CD (or CD-R/RW). Also called mini DVD. Most consumer DVD players can't play a cDVD.

cell - In DVD-Video, a unit of video anywhere from a fraction of a second to hours long. Cells allow the video to be grouped for sharing content among titles, interleaving for multiple angles, and so on.

Channel - A part of an audio track. Typically there is one channel allocated for each loudspeaker.

Chapter - In DVD-Video, a division of a title. Technically called a part of title (PTT).

CIF - Common intermediate format. Video resolution of 352x288.

Clamping area - The area near the inner hole of a disc where the drive grips the disc in order to spin it.

Closed caption - Textual video overlays that are not normally visible, as opposed to open captions, which are a permanent part of the picture. Captions are usually a textual representation of the spoken audio. In the United States, the official NTSC Closed Caption standard requires that all TVs larger than 13 inches include circuitry to decode and display caption information stored on line 21 of the video signal. DVD-Video can provide closed caption data, but the subpicture format is preferred for its versatility.

Codec - Coder/decoder. Circuitry or computer software that encodes and decodes a signal.

Colour depth - The number of levels of color (usually including luma and chroma) that can be represented by a pixel. Generally expressed as a number of bits or a number of colors. The color depth of MPEG video in DVD is 24 bits, although the chroma component is shared across 4 pixels (averaging 12 actual bits per pixel).

Colour difference - A pair of video signals that contain the color components minus the brightness component, usually B-Y and R-Y (G-Y is not used, since it generally carries less information). The color-difference signals for a black-and-white picture are zero. The advantage of color-difference signals is that the color component can be reduced more than the brightness (luma) component without being visually perceptible.

Combo drive - A DVD-ROM drive capable of reading and writing CD-R and CD-RW media. May also refer to a DVD-R or DVD-RW or DVD+RW drive with the same capability. (Also see RAMbo).

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. Very few televisions have component video inputs.

Compression - The process of removing redundancies in digital data to reduce the amount that must be stored or transmitted. Lossless compression removes only enough redundancy so that the original data can be recreated exactly as it was. Lossy compression sacrifices additional data to achieve greater compression.

Control area - A part of the lead-in area on a DVD containing one ECC block (16 sectors) repeated 192 times. The repeated ECC block holds information about the disc.

CPPM - Content Protection for Prerecorded Media. Copy protection for DVD-Audio.

CPRM - Content Protection for Recordable Media. Copy protection for writable DVD formats.

CPSA - Content Protection System Architecture. An overall copy protection design for DVD.

CPTWG - Copy Protection Technical Working Group. The industry body responsible for developing or approving DVD copy protection systems.

CPU - Central processing unit. The integrated circuit chip that forms the brain of a computer or other electronic device. DVD-Video players contain rudimentary CPUs to provide general control and interactive features.

Crop - To trim and remove a section of the video picture in order to make it conform to a different shape. Cropping is used in the pan & scan process, but not in the letterbox process.

Data area - The physical area of a DVD disc between the lead in and the lead out (or middle area) which contains the stored data content of the disc.

Data rate - The volume of data measured over time; the rate at which digital information can be conveyed. Usually expressed as bits per second with notations of kbps (thousand/sec), Mbps (million/sec), and Gbps (billion/sec). Digital audio date rate is generally computed as the number of samples per second times the bit size of the sample. For example, the data rate of uncompressed 16-bit, 48-kHz, two-channel audio is 1536 kbps. Digital video bit rate is generally computed as the number of bits per pixel times the number of pixels per line times the number of lines per frame times the number of frames per second. For example, the data rate of a DVD movie before compression is usually 12 ´ 720 ´ 480 ´ 24 = 99.5 Mbps. Compression reduces the data rate. Digital data rate is sometimes inaccurately equated with bandwidth.

Decode - To reverse the transformation process of an encoding method. Decoding processes are usually deterministic.

Decoder - 1) A circuit that decodes compressed audio or video, taking an encoded input stream and producing output such as audio or video. DVD players use the decoders to recreate information that was compressed by systems such as MPEG-2 and Dolby Digital; 2) a circuit that converts composite video to component video or matrixed audio to multiple channels.

Delta picture (or delta frame)- A video picture based on the changes from the picture before (or after) it. MPEG P pictures and B pictures are examples. Contrast with key picture.

Directory - The part of a disc that indicates what files are stored on the disc and where they are located.

Disc key - A value used to encrypt and decrypt (scramble) a title key on DVD-Video discs.

Disc menu - The main menu of a DVD-Video disc, from which titles are selected. Also called the system menu or title selection menu. Sometimes confusingly called the title menu, which more accurately refers to the menu within a title from which audio, subpicture, chapters, and so forth can be selected.

Display rate - The number of times per second the image in a video system is refreshed. Progressive scan systems such as film or HDTV change the image once per frame. Interlace scan systems such as standard television change the image twice per frame, with two fields in each frame. Film has a frame rate of 24 fps, but each frame is shown twice by the projector for a display rate of 48 fps. 525/60 (NTSC) television has a rate of 29.97 frames per second (59.94 fields per second). 625/50 (PAL/SECAM) television has a rate of 25 frames per second (50 fields per second).

Divx - Digital Video Express. A short-lived pay-per-viewing-period variation of DVD.

DLT - Digital linear tape. A digital archive standard using half-inch tapes, commonly used for submitting a premastered DVD disc image to a replication service.

Dolby Digital - A perceptual coding system for audio, developed by Dolby Laboratories and accepted as an international standard. Dolby Digital is the most common means of encoding audio for DVD-Video and is the mandatory audio compression system for 525/60 (NTSC) discs.

Dolby Pro Logic - The technique (or the circuit which applies the technique) of extracting surround audio channels from a matrix-encoded audio signal. Dolby Pro Logic is a decoding technique only, but is often mistakenly used to refer to Dolby Surround audio encoding.

Dolby Surround - The standard for matrix encoding surround-sound channels in a stereo signal by applying a set of defined mathematical functions when combining center and surround channels with left and right channels. The center and surround channels can then be extracted by a decoder such as a Dolby Pro Logic circuit which applies the inverse of the mathematical functions. A Dolby Surround decoder extracts surround channels, while a Dolby Pro Logic decoder uses additional processing to create a center channel. The process is essentially independent of the recording or transmission format. Both Dolby Digital and MPEG audio compression systems are compatible with Dolby Surround audio.

downmix - To convert a multichannel audio track into a two-channel stereo track by combining the channels with the Dolby Surround process. All DVD players are required to provide downmixed audio output from Dolby Digital audio tracks.

Driver - A software component that enables an application to communicate with a hardware device.

DSVCD - Double Super Video Compact Disc. Long-playing (100-minute) variation of SVCD.

DTS - Digital Theater Sound. A perceptual audio-coding system developed for theaters. A competitor to Dolby Digital and an optional audio track format for DVD-Video and DVD-Audio.

DTS-ES - A version of DTS decoding that is compatible with 6.1-channel Dolby Surround EX. DTS-ES Discrete is a variation of DTS encoding and decoding that carries a discrete rear center channel instead of a matrixed channel.

DTV - Digital television. In general, any system that encodes video and audio in digital form. In specific, the Digital Television System proposed by the ATSC or the digital TV standard proposed by the Digital TV Team founded by Microsoft, Intel, and Compaq.

Duplication - The reproduction of media. Generally refers to producing discs in small quantities, as opposed to large-scale replication.

DV - Digital Video. Usually refers to the digital videocassette standard developed by Sony and JVC.

DVD - An acronym that officially stands for nothing, but is often expanded as Digital Video Disc or Digital Versatile Disc. The audio/video/data storage system based on 12- and 8-cm optical discs.

DVD-Audio (DVD-A) - The audio-only format of DVD. Primarily uses PCM audio with MLP encoding, along with an optional subset of DVD-Video features.

DVD-R - A version of DVD on which data can be recorded once. Uses dye sublimation recording technology.

DVD-RAM - A version of DVD on which data can be recorded more than once. Uses phase-change recording technology.

DVD-ROM - The base format of DVD. ROM stands for read-only memory, referring to the fact that standard DVD-ROM and DVD-Video discs can't be recorded on. A DVD-ROM can store essentially any form of digital data.

DVD-Video (DVD-V) - A standard for storing and reproducing audio and video on DVD-ROM discs, based on MPEG video, Dolby Digital and MPEG audio, and other proprietary data formats.

DVI (Digital Visual Interface) - The digital video interface standard developed by the Digital Display Working Group (DDWG). A replacement for analog VGA monitor interface.

DVS - Descriptive video services. Descriptive narration of video for blind or sight-impaired viewers.

Dye polymer - The chemical used in DVD-R and CD-R media that darkens when heated by a high-power laser.

Dye-sublimation - Optical disc recording technology that uses a high-powered laser to burn readable marks into a layer of organic dye. Other recording formats include magneto-optical and phase-change.

dynamic range compression - A technique of reducing the range between loud and soft sounds in order to make dialogue more audible, especially when listening at low volume levels. Used in the downmix process of multichannel Dolby Digital sound tracks.

Dynamic range - The difference between the loudest and softest sound in an audio signal. The dynamic range of digital audio is determined by the sample size. Increasing the sample size does not allow louder sounds; it increases the resolution of the signal, thus allowing softer sounds to be separated from the noise floor (and allowing more amplification with less distortion). Dynamic range refers to the difference between the maximum level of distortion-free signal and the minimum limit reproducible by the equipment.

EDC - A short error-detection code applied at the end of a DVD sector.

Edge enhancement - When films are transferred to video in preparation for DVD encoding, they are commonly run through digital processes that attempt to clean up the picture. These processes include noise reduction (DVNR) and image enhancement. Enhancement increases contrast (similar to the effect of the "sharpen" or "unsharp mask" filters in PhotoShop), but can tend to overdo areas of transition between light and dark or different colors, causing a "chiseled" look or a ringing effect like the haloes you see around streetlights when driving in the rain. Video noise reduction is a good thing, when done well, since it can remove scratches, spots, and other defects from the original film. Enhancement, which is rarely done well, is a bad thing. The video may look sharper and clearer to the casual observer, but fine tonal details of the original picture are altered and lost.

EDS - Enhanced data services. Additional information in NTSC line such as a time signal.

EDTV - Enhanced-definition television. A system which uses existing transmission equipment to send an enhanced signal which looks the same on existing receivers but carries additional information to improve the picture quality on new enhanced receivers. PALPlus is an example of EDTV. (Contrast with HDTV and IDTV.)

EFM - Eight-to-fourteen modulation. A modulation method used by CD, where eight data bits are represented by 14 channel bits. The 8/16 modulation used by DVD is sometimes called EFM plus.

Encode - To transform data for storage or transmission, usually in such a way that redundancies are eliminated or complexity is reduced. Most compression is based on one or more encoding methods. Data such as audio or video is encoded for efficient storage or transmission and is decoded for access or display.

Encoder - 1) A circuit or program that encodes (and thereby compresses) audio or video; 2) a circuit that converts component digital video to composite analog video. DVD players include TV encoders to generate standard television signals from decoded video and audio; 3) a circuit that converts multichannel audio to two-channel matrixed audio.

Enhanced CD - A general term for various techniques that add computer software to a music CD, producing a disc which can be played in a music player or read by a computer. Also called CD Extra, CD Plus, hybrid CD, interactive music CD, mixed-mode CD, pre-gap CD, or track-zero CD.

Father - The metal master disc formed by electroplating the glass master. The father disc is used to make mother discs, from which multiple stampers (sons) can be made.

Forced display - A feature of DVD-Video allowing subpictures to be displayed even if the player's subpicture display mode is turned off. Designed for showing subtitles in a scene where the language is different from the native language of the film.

Formatting - 1) Creating a disc image. 2) Preparing storage media for recording.

Fps - Frames per second. A measure of the rate at which pictures are shown for a motion video image. In NTSC and PAL video, each frame is made up of two interlaced fields.

Frame rate - The frequency of discrete images. Usually measured in frames per second (fps). Film has a rate of 24 frames per second, but usually must be adjusted to match the display rate of a video system.

Frame - The piece of a video signal containing the spatial detail of one complete image; the entire set of scan lines. In an interlaced system, a frame contains two fields.

H/DTV - High-definition/digital television. A combination of acronyms that refers to both HDTV and DTV systems.

HDTV - High-definition television. A video format with a resolution approximately twice that of conventional television in both the horizontal and vertical dimensions, and a picture aspect ratio of 16:9. Used loosely to refer to the U.S. DTV System. Contrast with EDTV and IDTV.

HHR - Horizontal Half Resolution. MPEG-2 picture resolution of 352 x 480 (NTSC) or 352 x 576 (PAL/SECAM). Supported by the DVD-Video specification. Encoding video at HHR greatly reduces the bandwidth with a minor reduction in picture quality. Also called Half D1.

Horizontal resolution - See lines of horizontal resolution.

Jewel box - The plastic clamshell case that holds a CD or DVD.

Karaoke - Literally empty orchestra. The social sensation from Japan where sufficiently inebriated people embarrass themselves in public by singing along to a music track. Karaoke was largely responsible for the success of laserdisc in Japan, thus supporting it elsewhere.

Key picture (or key frame)- A video picture containing the entire content of the image (intraframe encoding), rather than the difference between it and another image (interframe encoding). MPEG I pictures are key pictures. Contrast with delta picture.

Laserdisc - A 12-inch (or 8-inch) optical disc that holds analog video (using an FM signal) and both analog and digital (PCM) audio. A precursor to DVD.

Layer - The plane of a DVD disc on which information is recorded in a pattern of microscopic pits. Each substrate of a disc can contain one or two layers. The first layer, closest to the readout surface, is layer 0; the second is layer 1.

Legacy - A term used to describe a hybrid disc that can be played in both a DVD player and a CD player.

Letterbox filter - Circuitry in a DVD player that reduces the vertical size of anamorphic widescreen video (combining every 4 lines into 3) and adds black mattes at the top and bottom. Also see filter.

letterbox - The process or form of video where black horizontal mattes are added to the top and bottom of the display area in order to create a frame in which to display video using an aspect ratio different than that of the display. The letterbox method preserves the entire video picture, as opposed to pan & scan. DVD-Video players can automatically letterbox a widescreen picture for display on a standard 4:3 TV.

Lines of horizontal resolution - Sometimes abbreviated as TVL (TV lines) or LoHR. A common but subjective measurement of the visually resolvable horizontal detail of an analog video system, measured in half-cycles per picture height. Each cycle is a pair of vertical lines, one black and one white. The measurement is usually made by viewing a test pattern to determine where the black and white lines blur into gray. The resolution of VHS video is commonly gauged at 240 lines of horizontal resolution, broadcast video at 330, laserdisc at 425, and DVD at 500 to 540. Because the measurement is relative to picture height, the aspect ratio must be taken into account when determining the number of vertical units (roughly equivalent to pixels) that can be displayed across the width of the display. For example, an aspect ratio of 1.33 multiplied by 540 gives 720 pixels.

Logical unit - A physical or virtual peripheral device, such as a DVD-ROM drive.

Logical - An artificial structure or organization of information created for convenience of access or reference, usually different from the physical structure or organization. For example, the application specifications of DVD (the way information is organized and stored) are logical formats.

Macrovision - An antitaping process that modifies a signal so that it appears unchanged on most televisions but is distorted and unwatchable when played back from a videotape recording. Macrovision takes advantage of characteristics of AGC circuits and burst decoder circuits in VCRs to interfere with the recording process.

megapixel - A term referring to an image or display format with a resolution of approximately 1 million pixels.

Memory - Data storage used by computers or other digital electronics systems. Read-only memory (ROM) permanently stores data or software program instructions. New data cannot be written to ROM. Random-access memory (RAM) temporarily stores data-including digital audio and video-while it is being manipulated, and holds software application programs while they are being executed. Data can be read from and written to RAM. Other long-term memory includes hard disks, floppy disks, digital CD formats (CD-ROM, CD-R, and CD-RW), and DVD formats (DVD-ROM, DVD-R, and DVD-RAM).

Mini DVD - 1) Small size (8-cm) DVD. 2) DVD-Video content stored on a CD (or CD-R/RW). Less ambiguously called cDVD.

Modulation - Replacing patterns of bits with different (usually larger) patterns designed to control the characteristics of the data signal. DVD uses 8/16 modulation, where each set of 8 data bits is replaced by 16 channel bits before being written onto the disc.

Mother - The metal discs produced from mirror images of the father disc in the replication process. Mothers are used to make stampers, often called sons

MP@ML - Main profile at main level. The common MPEG-2 format used by DVD (along with SP@SL).

MP3 - MPEG-1 Layer III audio. A perceptual audio coding algorithm. Not supported in DVD-Video or DVD-Audio formats.

MPEG audio - Audio compressed according to the MPEG perceptual encoding system. MPEG-1 audio provides two channels, which can be in Dolby Surround format. MPEG-2 audio adds data to provide discrete multichannel audio. Stereo MPEG audio is the mandatory audio compression system for 625/50 (PAL/SECAM) DVD-Video.

MPEG video - Video compressed according to the MPEG encoding system. MPEG-1 is typically used for low data rate video such as on a Video CD. MPEG-2 is used for higher-quality video, especially interlaced video, such as on DVD or HDTV. (See Table 3.5 for a comparison of MPEG-1 and MPEG-2.)

MPEG - Moving Pictures Expert Group. An international committee that developed the MPEG family of audio and video compression systems.

multiangle - A DVD-Video program containing multiple angles allowing different views of a scene to be selected during playback.

multichannel - Multiple channels of audio, usually containing different signals for different speakers in order to create a surround-sound effect.

multilanguage - A DVD-Video program containing sound tracks and subtitle tracks for more than one language.

Multimedia - Information in more than one form, such as text, still images, sound, animation, and video. Usually implies that the information is presented by a computer.

MultiRead - A standard developed by the Yokohama group, a consortium of companies attempting to ensure that new CD and DVD hardware can read all CD formats (see "Innovations of CD" in Chapter 2 for a discussion of CD variations).

NTSC - National Television Systems Committee. A committee organized by the Electronic Industries Association (EIA) that developed commercial television broadcast standards for the United States. The group first established black-and-white TV standards in 1941, using a scanning system of 525 lines at 60 fields per second. The second committee standardized color enhancements using 525 lines at 59.94 fields per second. NTSC refers to the composite color-encoding system. The 525/59.94 scanning system (with a 3.58-MHz color subcarrier) is identified by the letter M, and is often incorrectly referred to as NTSC. The NTSC standard is also used in Canada, Japan, and other parts of the world. NTSC is facetiously referred to as meaning never the same color because of the system's difficulty in maintaining color consistency.

NTSC-4.43 - A variation of NTSC where a 525/59.94 signal is encoded using the PAL subcarrier frequency and chroma modulation. Also called 60-Hz PAL.

Orange Book - The document begun in 1990 which specifies the format of recordable CD. Three parts define magneto-optical erasable (MO) and write-once (WO), dye-sublimation write-once (CD-R), and phase-change rewritable (CD-RW) discs. Orange Book added multisession capabilities to the CD-ROM XA format.

OTP - Opposite track path. A variation of DVD dual-layer disc layout where readout begins at the center of the disc on the first layer, travels to the outer edge of the disc, then switches to the second layer and travels back toward the center. Designed for long, continuous-play programs. Also called RSDL. Contrast with PTP.

Pack - A group of MPEG packets in a DVD-Video program stream. Each DVD sector (2048 bytes) contains one pack.

Packet - A low-level unit of DVD-Video (MPEG) data storage containing contiguous bytes of data belonging to a single elementary stream such as video, audio, control, and so forth. Packets are grouped into packs.

PAL - Phase Alternate Line. A video standard used in Europe and other parts of the world for composite color encoding. Various version of PAL use different scanning systems and color subcarrier frequencies (identified with letters B, D, G, H, I, M, and N), the most common being 625 lines at 50 fields per second, with a color subcarrier of 4.43 MHz. PAL is also said to mean "picture always lousy" or "perfect at last," depending on which side of the ocean the speaker comes from.

Palette - A table of colours that identifies a subset from a larger range of colors. The small number of colors in the palette allows fewer bits to be used for each pixel. Also called a colour look-up table (CLUT).

Pan & scan - The technique of reframing a picture to conform to a different aspect ratio by cropping parts of the picture. DVD-Video players can automatically create a 4:3 pan & scan version from widescreen video by using a horizontal offset encoded with the video.

Parental management - An optional feature of DVD-Video that prohibits programs from being viewed or substitutes different scenes within a program depending on the parental level set in the player. Parental control requires that parental levels and additional material (if necessary) be encoded on the disc.

Part of title - In DVD-Video, a division of a title representing a scene. Also called a chapter. Parts of titles are numbered 1 to 99.

PCI - Presentation control information. A DVD-Video data stream containing details of the timing and presentation of a program (aspect ratio, angle change, menu highlight and selection information, and so on). PCI and DSI together make up an overhead of about 1 Mbps.

PC-TV - The merger of television and computers. A personal computer capable of displaying video as a television.

Physical format - The low-level characteristics of the DVD-ROM and DVD-Video standards, including pits on the disc, location of data, and organization of data according to physical position.

Picture stop - A function of DVD-Video where a code indicates that video playback should stop and a still picture be displayed.

Picture - In video terms, a single still image or a sequence of moving images. Picture generally refers to a frame, but for interlaced frames may refer instead to a field of the frame. In a more general sense, picture refers to the entire image shown on a video display.

PIP - Picture in picture. A feature of some televisions that shows another channel or video source in a small window superimposed in a corner of the screen.

Pixel aspect ratio - The ratio of width to height of a single pixel. Often means sample pitch aspect ratio (when referring to sampled digital video). Pixel aspect ratio for a given raster can be calculated as y/x x w/h (where x and y are the raster horizontal pixel count and vertical pixel count, and w and h are the display aspect ratio width and height). Pixel aspect ratios are also confusingly calculated as x/y x w/h, giving a height-to-width ratio.

Pixel - The smallest picture element of an image (one sample of each color component). A single dot of the array of dots that makes up a picture. Sometimes abbreviated to pel. The resolution of a digital display is typically specified in terms of pixels (width by height) and color depth (the number of bits required to represent each pixel).

PMMA - Polymethylmethacrylate. A clear acrylic compound used in laserdiscs and as an intermediary in the surface transfer process (STP) for dual-layer DVDs. PMMA is also sometimes used for DVD substrates.

POP - Picture outside picture. A feature of some widescreen displays that uses the unused area around a 4:3 picture to show additional pictures.

premastering - The process of preparing data in the final format to create a DVD disc image for mastering. Includes creating DVD control and navigation data, multiplexing data streams together, generating error-correction codes, and performing channel modulation. Often includes the process of encoding video, audio, and subpictures.

presentation data - DVD-Video information such as video, menus, and audio which is presented to the viewer.

Program chain - In DVD-Video, a collection of programs, or groups of cells, linked together to create a sequential presentation.

Program - In a general sense, a sequence of audio or video. In a technical sense for DVD-Video, a group of cells within a program chain (PGC).

PTP - Parallel track path. A variation of DVD dual-layer disc layout where readout begins at the center of the disc for both layers. Designed for separate programs (such as a widescreen and a pan & scan version on the same disc side) or programs with a variation on the second layer. Also most efficient for DVD-ROM random-access application.

RAM - Random-access memory. Generally refers to solid-state chips. In the case of DVD-RAM, the term was borrowed to indicate ability to read and write at any point on the disc.

RAMbo drive - A DVD-RAM drive capable of reading and writing CD-R and CD-RW media. (A play on the word "combo.")

Read-modify-write - An operation used in writing to DVD-RAM discs. Because data can be written by the host computer in blocks as small as 2 KB, but the DVD format uses ECC blocks of 32 KB, an entire ECC block is read from the data buffer or disc, modified to include the new data and new ECC data, then written back to the data buffer and disc.

Red Book - The document first published in 1982 that specifies the original compact disc digital audio format developed by Philips and Sony.

Reed-Solomon - An error-correction encoding system that cycles data multiple times through a mathematical transformation in order to increase the effectiveness of the error correction, especially for burst errors (errors concentrated closely together, as from a scratch or physical defect). DVD uses rows and columns of Reed-Solomon encoding in a two-dimensional lattice, called Reed-Solomon product code (RS-PC).

Reference player - A DVD player that defines the ideal behavior as specified by the DVD-Video standard.

Regional code - A code identifying one of the world regions for restricting DVD-Video playback.

Regional management - A mandatory feature of DVD-Video to restrict the playback of a disc to a specific geographical region. Each player and DVD-ROM drive includes a single regional code, and each disc side can specify in which regions it is allowed to be played. Regional coding is optional-a disc without regional codes will play in all players in all regions.

replication - 1) The reproduction of media such as optical discs by stamping (contrast with duplication); 2) a process used to increase the size of an image by repeating pixels (to increase the horizontal size) and/or lines (to increase the vertical size) or to increase the display rate of a video stream by repeating frames. For example, a 360 x 240 pixel image can be displayed at 720 x 480 size by duplicating each pixel on each line and then duplicating each line. In this case the resulting image contains blocks of four identical pixels. Obviously, image replication can cause blockiness. A 24-fps video signal can be displayed at 72 fps by repeating each frame three times. Frame replication can cause jerkiness of motion. Contrast with decimation. Also see interpolate.

resampling - The process of converting between different spatial resolutions or different temporal resolutions. This may be based on simple sampling of the source information at higher or lower resolution or may include interpolation to correct for differences in pixel aspect ratios or to adjust for differences in display rates.

Resolution - 1) A measurement of relative detail of a digital display, typically given in pixels of width and height; 2) the ability of an imaging system to make clearly distinguishable or resolvable the details of an image. This includes spatial resolution (the clarity of a single image), temporal resolution (the clarity of a moving image or moving object), and perceived resolution (the apparent resolution of a display from the observer's point of view). Analog video is often measured as a number of lines of horizontal resolution over the number of scan lines. Digital video is typically measured as a number of horizontal pixels by vertical pixels. Film is typically measured as a number of line pairs per millimeter; 3) the relative detail of any signal, such as an audio or video signal. Also see lines of horizontal resolution.

RGB - Video information in the form of red, green, and blue tristimulus values. The combination of three values representing the intensity of each of the three colors can represent the entire range of visible light.

ROM - Read-only memory.

Rpm - Revolutions per minute. A measure of rotational speed.

RS - Reed-Solomon. An error-correction encoding system that cycles data multiple times through a mathematical transformation in order to increase the effectiveness of the error correction. DVD uses rows and columns of Reed-Solomon encoding in a two-dimensional lattice, called Reed-Solomon product code (RS-PC).

S/P DIF - Sony/Philips digital interface. A consumer version of the AES/EBU digital audio transmission standard. Most DVD players include S/P DIF coaxial digital audio connectors providing PCM and encoded digital audio output.

Sample rate - The number of times a digital sample is taken, measured in samples per second, or Hertz. The more often samples are taken, the better a digital signal can represent the original analog signal. Sampling theory states that the sampling frequency must be more than twice the signal frequency in order to reproduce the signal without aliasing. DVD PCM audio allows sampling rates of 48 and 96 kHz.

Sample size - The number of bits used to store a sample. Also called resolution. In general, the more bits allocated per sample, the better the reproduction of the original analog information. Audio sample size determines the dynamic range. DVD PCM audio uses sample sizes of 16, 20, or 24 bits.

Sample - A single digital measurement of analog information. A snapshot in time of a continuous analog waveform. See sampling.

Sampling - Converting analog information into a digital representation by measuring the value of the analog signal at regular intervals, called samples, and encoding these numerical values in digital form. Sampling is often based on specified quantization levels. Sampling may also be used to adjust for differences between different digital systems.

Saturation - The intensity or vividness of a color.

Scaling - Altering the spatial resolution of a single image to increase or reduce the size; or altering the temporal resolution of an image sequence to increase or decrease the rate of display. Techniques include decimation, interpolation, motion compensation, replication, resampling, and subsampling. Most scaling methods introduce artifacts.

Scan line - A single horizontal line traced out by the scanning system of a video display unit. 525/60 (NTSC) video has 525 scan lines, about 480 of which contain actual picture. 625/50 (PAL/SECAM) video has 625 scan lines, about 576 of which contain actual picture.

Scanning velocity - The speed at which the laser pickup head travels along the spiral track of a disc.

SCMS - Serial copy management system. Used by DAT, MiniDisc, and other digital recording systems to control copying and limit the number of copies that can be made from copies.

SCSI - Small Computer Systems Interface. An electronic interface and command set for attaching and controlling internal or external peripherals, such as a DVD-ROM drive, to a computer. The command set of SCSI was extended for DVD-ROM devices by the SFF 8090 specification.

SDDI - Serial Digital Data Interface. A digital video interconnect designed for serial digital information to be carried over a standard SDI connection.

SDDS - Sony Dynamic Digital Sound. A perceptual audio-coding system developed by Sony for multichannel audio in theaters. A competitor to Dolby Digital and an optional audio track format for DVD.

SDI - See Serial Digital Interface. Also Strategic Defense Initiative, a.k.a. Star Wars, which as of 2000 was still not available on DVD other than as bootleg copies.

SDTV - Standard-definition television. A term applied to traditional 4:3 television (in digital or analog form) with a resolution of about 700 x 480 (about 1/3 megapixel). Contrast with HDTV.

Seamless playback - A feature of DVD-Video where a program can jump from place to place on the disc without any interruption of the video. Allows different versions of a program to be put on a single disc by sharing common parts.

SECAM - Séquential couleur avec mémoire/sequential color with memory. A composite color standard similar to PAL, but currently used only as a transmission standard in France and a few other countries. Video is produced using the 625/50 PAL standard and is then transcoded to SECAM by the player or transmitter.

Sector - A logical or physical group of bytes recorded on the disc-the smallest addressable unit. A DVD sector contains 38,688 bits of channel data and 2048 bytes of user data.

Seek time - The time it takes for the head in a drive to move to a data track.

Serial Digital Interface (SDI) - The professional digital video connection format using a 270 Mbps transfer rate. A 10-bit, scrambled, polarity-independent interface, with common scrambling for both component ITU-R 601 and composite digital video and four groups each of four channels of embedded digital audio. SDI uses standard 75-ohm BNC connectors and coax cable.

Son - The metal discs produced from mothers discs in the replication process. Fathers or sons are used in molds to stamp discs.

SP@ML - Simple profile at main level. The simplest MPEG-2 format used by DVD. Most discs use MP@ML. SP does not allow B pictures.

Space - The reflective area of a writable optical disc. Equivalent to a land.

Spatial resolution - The clarity of a single image or the measure of detail in an image. See resolution.

Spatial - Relating to space, usually two-dimensional. Video can be defined by its spatial characteristics (information from the horizontal plane and vertical plane) and its temporal characteristics (information at different instances in time).

Stamping - The process of replicating optical discs by injecting liquid plastic into a mold containing a stamper (father or son). Also (inaccurately) called mastering.

Stream - A continuous flow of data, usually digitally encoded, designed to be processed sequentially. Also called a bitstream.

subpicture - Graphic bitmap overlays used in DVD-Video to create subtitles, captions, karaoke lyrics, menu highlighting effects, and so on.

subsampling - The process of reducing spatial resolution by taking samples that cover larger areas than the original samples or of reducing temporal resolutions by taking samples that cover more time than the original samples.

Substrate - The clear polycarbonate disc onto which data layers are stamped or deposited.

Subtitle - A textual representation of the spoken audio in a video program. Subtitles are often used with foreign languages and do not serve the same purpose as captions for the hearing impaired. 

Surround sound - A multichannel audio system with speakers in front of and behind the listener to create a surrounding envelope of sound and to simulate directional audio sources.

SVCD - Super Video Compact Disc. MPEG-2 video on CD. Used primarily in Asia.

SVGA - A video graphics resolution of 800 x 600 pixels.

S-VHS - Super VHS (Video Home System). An enhancement of the VHS videotape standard using better recording techniques and Y/C signals. The term S-VHS is often used incorrectly to refer to s-video signals and connectors.

S-video - A video interface standard that carries separate luma and chroma signals, usually on a four-pin mini-DIN connector. The quality of s-video is significantly better than composite video since it does not require a comb filter to separate the signals, but it's not quite as good as component video. Most high-end televisions have s-video inputs. S-video is often erroneously called S-VHS.

SXGA - A video graphics resolution of 1280 x 1024 pixels.

System menu - The main menu of a DVD-Video disc, from which titles are selected. Also called the title selection menu or disc menu.

Temporal resolution - The clarity of a moving image or moving object, or the measurement of the rate of information change in motion video. See resolution.

Temporal - Relating to time. The temporal component of motion video is broken into individual still pictures. Because motion video can contain images (such as backgrounds) that do not change much over time, typical video has large amounts of temporal redundancy.

Time code - Information recorded with audio or video to indicate a position in time. Usually consists of values for hours, minutes, seconds, and frames. Also called SMPTE time code. Some DVD-Video material includes information to allow the player to search to a specific time code position.

Title key - A value used to encrypt and decrypt (scramble) user data on DVD-Video discs.

Title - The largest unit of a DVD-Video disc (other than the entire volume or side). Usually a movie, TV program, music album, or so on. A disc can hold up to 99 titles, which can be selected from the disc menu. Entire DVD volumes are also commonly called titles.

track buffer - Circuitry (including memory) in a DVD player that provides a variable stream of data (up to 10.08 Mbps) to the system decoders of data coming from the disc at a constant rate of 11.08 Mbps (except for breaks when a different part of the disc is accessed).

Track pitch - The distance (in the radial direction) between the centers of two adjacent tracks on a disc. DVD-ROM standard track pitch is 0.74 mm.

Track - 1) A distinct element of audiovisual information, such as the picture, a sound track for a specific language, or the like. DVD-Video allows one track of video (with multiple angles), up to 8 tracks of audio, and up to 32 tracks of subpicture; 2) one revolution of the continuous spiral channel of information recorded on a disc.

Transfer rate - The speed at which a certain volume of data is transferred from a device such as a DVD-ROM drive to a host such as a personal computer. Usually measured in bits per second or bytes per second. Sometimes confusingly used to refer to data rate, which is independent of the actual transfer system.

UDF - Universal Disc Format. A standard developed by the Optical Storage Technology Association designed to create a practical and usable subset of the ISO/IEC 13346 recordable, random-access file system and volume structure format.

Universal DVD - A DVD designed to play in DVD-Audio and DVD-Video players (by carrying a Dolby Digital audio track in the DVD-Video zone).

Universal DVD player - A DVD player that can play both DVD-Video and DVD-Audio discs.

User data - The data recorded on a disc independent of formatting and error-correction overhead. Each DVD sector contains 2048 bytes of user data.

UXGA - A video graphics resolution of 1600x1200.

VBI - Vertical blanking interval. The scan lines in a television signal that do not contain picture information. These lines are present to allow the electron scanning beam to return to the top and are used to contain auxiliary information such as closed captions.

VBV - Video buffering verifier. A hypothetical decoder that is conceptually connected to the output of an MPEG video encoder. Provides a constraint on the variability of the data rate that an encoder can produce.

VCAP Video Capable Audio Player - An audio player which can read the limited subset of video features defined for the DVD-Audio format

VCD - Video Compact Disc. Near-VHS-quality MPEG-1 video on CD. Used primarily in Asia.

VGA (Video Graphics Array) - A standard analog monitor interface for computers. Also a video graphics resolution of 640 x 480 pixels.

VHS - Video Home System. The most popular system of videotape for home use. Developed by JVC.

Video CD - An extension of CD based on MPEG-1 video and audio. Allows playback of near-VHS-quality video on a Video CD player, CD-i player, or computer with MPEG decoding capability.

Video manager (VMG) - The disc menu. Also called the title selection menu.

Video title set (VTS) - A set of one to ten files holding the contents of a title.

VOB - Video object. A small physical unit of DVD-Video data storage, usually a GOP.

Watermark - Information hidden as "invisible noise" or "inaudible noise" in a video or audio signal.

White Book - The document from Sony, Philips, and JVC, begun in 1993 that extended the Red Book compact disc format to include digital video in MPEG-1 format. Commonly called Video CD.

widescreen - A video image wider than the standard 1.33 (4:3) aspect ratio. When referring to DVD or HDTV, widescreen usually indicates a 1.78 (16:9) aspect ratio.

Window - A usually rectangular section within an entire screen or picture.

XGA - A video graphics resolution of 1024 x 768 pixels.

XVCD - A non-standard variation of VCD.

Yellow Book - The document produced in 1985 by Sony and Philips that extended the Red Book compact disc format to include digital data for use by a computer. Commonly called CD-ROM.

 

DVD Region Information

DVD-Video discs may be encoded with a region code restricting the area of the world in which they can be played. Discs without region coding are called all region, region 0 or multi-zone discs.

The commercial DVD player specification requires that a player to be sold in a given place must not play discs encoded for a different region (region 0 discs are not restricted). The purpose of this is to allow motion picture studios to control aspects of a release, including content, date, and in particular, price, according to the region. Many DVD players are or can be modified to be region-free, allowing playback of all discs.

 

 

Region code	Area
0	Informal term meaning "worldwide". Region 0 is not an official setting; discs that bear the region 0 symbol either have no flag set or have region 1-6 flags set.
1	Bermuda, Canada, United States and U.S. territories
2	European Union, Albania, Andorra, Armenia, Bahrain, Bosnia and Herzegovina, Croatia, Denmark, Egypt, Faroe Islands, French overseas territories, Georgia, Greenland, Guernsey, Iceland, Iran, Iraq, Isle of Man, Israel, Japan, Jersey, Jordan, Kuwait, Lebanon, Lesotho, Liechtenstein, Macedonia, Moldova, Monaco, Montenegro, Norway, Oman, Qatar, San Marino, Saudi Arabia, Serbia, South Africa, Sweden, Swaziland, Switzerland, Syria, Turkey, United Arab Emirates, Vatican City State, Yemen
3	Southeast Asia, Hong Kong, Macau, South Korea, Taiwan, Philippines
4	Australia, New Zealand, Caribbean, Central America, Oceania, Jamaica (except French Guiana), Mexico, South America
5	African countries not explicitly included in other regions, Indian subcontinent, countries included in the former Soviet Union, Mongolia, North Korea
6	People's Republic of China (exclude Macau, Taiwan)
7	Reserved for future use (found in use on protected screener copies of MPAA-related DVDs and "media copies" of pre-releases in Asia)
8	International venues such as aircraft, cruise ships, etc.
ALL	Region ALL discs have all 8 flags set, allowing the disc to be played in any locale on any player.

 

 

DVDs sold in the Baltic States use both region 2 and 5 codes. DVDs sold in Japan use the region 2 code and Hong Kong, Macau and Taiwan use the region 3 code, with Hong Kong sharing region 6 for releases after the reunification. Region 0 (playable in all regions, except 7/8) is widely used by China, the Philippines, Hong Kong, Macau, and Taiwan. DVDs in Latin American Spanish use both the region 1 and region 4 codes. Most DVDs in India combine the region 2, region 4, and region 5 codes; Disney discs contain only the region 3 code.

European region 2 DVDs may be sub-coded "D1" to "D4". "D1" are United Kingdom-only releases; "D2" and "D3" are not sold in the UK and Ireland; "D4" are distributed throughout Europe.

Any combination of regions can be applied to a single disc. For example, a DVD designated Region 2/4 is suitable for playback in Western Europe, Oceania, and any other Region 2 or Region 4 area. So-called "Region 0" and "ALL" discs are meant to be playable worldwide.

The term "Region 0" also describes the DVD players designed or modified to incorporate Regions 1-6, thereby providing compatibility with most players/discs, irrespective of region[s]. This apparent solution was popular in the early days of the DVD format, but studios quickly responded by adjusting discs to refuse to play in such machines. This system is known as "Regional Coding Enhancement".

It may be difficult for American companies to enforce their copyright rights in the countries in the Region 5 area, and thus Region 5 DVDs may be released earlier than Region 1 DVDs to encourage consumers to opt for a legal version, rather than a pirated copy of a DVD screener. Many of the countries in the region 5 area were historically either incapable or unwilling to uphold American copyrights. In many of the countries in the Region 5 area, war or extreme poverty make intellectual property rights a low-priority interest for the governments.

 

Region Code Enhanced

Also known as just "RCE" or "REA", ^[1] this was a retroactive attempt to prevent the playing of one region's discs in another region, even if the disc was played in a region free player. The scheme was deployed on only a handful of discs. The disc contained the main programme material region coded as region 1. But it also contained a short video loop of a map of the world showing the regions, which was coded as region 2, 3, 4, 5, and 6. The idea was that when the disc was played in a non-region 1 player, the player would default to playing the material for its native region. This played the map, which was impossible to escape from, as the user controls were disabled.

However, the designers of the scheme failed to fully understand the mechanism by which region-free players worked, and thus a workaround was quickly found. A region-free player tries to play a disc using the last region that worked with the previously inserted disc. If it cannot play the disc, then it tries another region until one is found that works. RCE could thus be defeated by briefly playing a "normal" region 1 disc, and then inserting the RCE protected region 1 disc, which would now play. RCE caused a few problems with genuine region 1 players.

As of 2007 many "multi-region" DVD players defeat regional lockout and RCE by automatically identifying and matching a disc's region code and/or allowing the user to manually select a particular region. Some manufacturers of DVD players now freely supply information on how to disable regional lockout, and on some recent models, it appears to be disabled by default. Programs such as DVD Shrink are also capable of removing RCE protection, provided the operator knows what the region of the disk actually is. If the region is specified correctly, the copy will play in any region.

Legal concerns

Region codes were officially implemented to restrict the sale of titles to designated regions, so that, for example, a DVD could be released in the United States before the movie was released to the cinemas in Europe.

However, region code enforcement has been discussed as a possible violation of World Trade Organization free trade agreements or competition law. The Australian Competition and Consumer Commission (ACCC) have warned that DVD players that enforce region coding may violate the Trade Practices Act. The government of New Zealand is also considering a similar ruling. This, supposedly, means that all DVD players sold in their territories have to be region-free.

Region coding was misused when older material was released with full region coding-there being no requirement, per the stated cinema-blockout justification provided, to restrict sales to certain countries. There are concerns, echoed by organisations such as the European Union, that region coding was solely an attempt to enforce price differentials.

Standalone DVD players

Usually a configuration flag is set in each player's firmware at the factory. This flag holds the region number that the machine is allowed to play. Region-free players are DVD players shipped without the ability to enforce regional lockout (usually by means of a chip that ignores any region coding), or without this flag set. This was partly a result of a landmark ACCC case in which the High Court of Australia ruled that region lockouts breached fair trade and market competition practices.

However, if the player is not region-free, it can often be unlocked with an unlock code entered via the remote control. This code simply allows the user to change the factory-set configuration flag to another region, or to the special region "0". Once unlocked this way, the DVD player allows the owner to watch DVDs from any region. Many websites exist on the Internet offering these codes, often known informally as hacks.

Computer DVD drives

Older DVD drives use RPC-1 firmware, which means the drive allows DVDs from any region to play. Newer drives use RPC-2 firmware, which enforces the DVD region coding at the hardware level. These drives can often be reflashed with hacked or Australia and New Zealand (hardware region coding prohibited by law in these countries) RPC-1 firmware, effectively making the drive region-free. However, this usually voids the warranty and can render the drive inoperable if something goes wrong.

Software DVD players

Most freeware and open source DVD players ignore region coding. Most commercial players are locked to a region code, but can be easily changed with software.

Other software, known as DVD region killers, transparently remove (or hide) the DVD region code from the software player. Some can also work around locked RPC-2 firmware.

DVD Discs

DVD discs do not enforce their region codes; they rely on the player to do that. Region codes can thus be removed from the DVD by burning a copy that adds flags for all region codes, creating an all-region DVD. DVD backup software is used for this, and can usually remove Macrovision, CSS, and disabled user operations (UOPs) as well.

NTSC, PAL/SECAM

Because of digital technology these systems are slowly being phased out. Having to do with analog television, these had an effect like regional coding. In actuality, they were the systems used in various parts of the world relating with how analog television signals were sent and received. Video in the UK and parts of Europe using the PAL system ran video frames at a rate of 25 per second. While in the US, Canada, and Japan, using the NTSC system, the video frames ran at a rate of about 29.97 per second. NTSC was set in this manner because it had less wave distortion with the AC voltage frequency of 60Hz when an analog television set was plugged in. SECAM is a French system that helped improve video efficiency in signal transmission for PAL system televisions. It was adopted in some areas, and was somewhat used as a region filter in parts of Europe, although many people would buy set top converters to view both PAL & SECAM transmissions in areas where it was used in such a method.

Since North America and Japan both used NTSC, different regional codes could be used to separate the 2 regions: the US using Region 1 coding and Japan using Region 2. UK also uses Region 2 coding. These artificial limitations were not present in earlier LaserDisc and video cassette technology. Using the older LaserDisc or video cassette system, one could purchase video media in Japan and easily view it in the US. Another example is playing DVDs from Mexico and Australia on a DVD player that is flagged for Region 4, despite the different formats between the two countries (Much of Latin America uses NTSC [including Mexico], while much of Oceania [including Australia] uses PAL).

On a side note: The audio for NTSC and PAL were along the same track in magnetic video cassettes, it is not uncommon to place a PAL cassette in an NTSC cassette player (or NTSC cassette in a PAL player) and hear the audio clearly (although at incorrect speed) with distorted video. Region encoding in digital players helped block this as well.

With newer-style digital televisions and the use of variable frequency and resolution monitors, NTSC, PAL/SECAM are really no longer necessary. With the advent of internet and access to digital video online, region encoding is finding hurdles of its own and may slowly fade away the way NTSC, PAL/SECAM are.

Note that many people confuse Regional Coding with a form of Encryption. In reality, Regional Coding is an even cruder form of imposing geographical limitations on physical media traveling across borders, whereas the [CSS] copy protection used on DVD was designed to prevent the disc's content being copied - not to regulate where in the world it is played. As such, references to "Region Encryption" are a misnomer.

 

 

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