Terminology - Video Terms
Video Services, Video Capture, Video Transfer to DVD.
1080i - 1080 lines of interlaced video (540 lines per field). Usually refers to 1920x1080 resolution in 1.78 aspect ratio.
1080p - 1080 lines of progressive video (1080 lines per frame). Usually refers to 1920x1080 resolution in 1.78 aspect ratio.
2-2 pulldown - The process of transferring 24-frame-per-second film to video by repeating each film frame as two video fields. When 24-fps film is converted via 2-2 pulldown to 25-fps 625/50 (PAL) video, the film runs 4 percent faster than normal.
2-3 pulldown - The process of converting 24-frame-per-second film to video by repeating one film frame as three fields, then the next film frame as two fields.
3" Mini Flex VCD HD - Flex VCD is the latest technology in the DVD manufacturing sector offering video services. The single layer format has the same capacity of a 3" Mini DVD-5 (1.1GB), but is half the thickness of a standard DVD. This new disc format is literally "flexible". This new format is ideal for any disc based direct mail application due to its resilience to breakage, shattering, and cracking.
3-2 pulldown - An uncommon variation of 2-3 pulldown, where the first film frame is repeated for 3 fields instead of two. Most people mean 2-3 pulldown when they say 3-2 pulldown.
4:1:1 - The component digital video format with one Cb sample and one Cr sample for every four Y samples. 4:1 horizontal downsampling with no vertical downsampling. Chroma is sampled on every line, but only for every four luma pixels (i.e., 1 pixel in a 1 x 4 grid). 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). DVD uses 4:2:0 sampling, not 4:1:1 sampling.
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).
4:2:2 - The component digital video format commonly used for studio recordings, where there is one Cb sample and one Cr sample for every two Y samples (i.e., 1 pixel in a 1 x 2 grid). 2:1 horizontal downsampling with no vertical downsampling. This allocates the same number of samples to the chroma signal as to the luma signal. The input to MPEG-2 encoders used for DVD is typically in 4:2:2 format, but the video is subsampled to 4:2:0 before being encoded and stored.
4:4:4 - A component digital video format for high-end studio recordings, where Y, Cb, and Cr are sampled equally.
480i - 480 lines of interlaced video (240 lines per field). Usually refers to 720 x 480 (or 704 x 480) resolution.
480p - 480 lines of progressive video (480 lines per frame). 480p60 refers to 60 frames per second; 480p30 refers to 30 frames per second; and 480p24 refers to 24 frames per second (film source). Usually refers to 720 x 480 (or 704 x 480) resolution.
525/60 - The scanning system of 525 lines per frame and 60 interlaced fields (30 frames) per second. Used by the NTSC television standard.
625/50 - The scanning system of 625 lines per frame and 50 interlaced fields (25 frames) per second. Used by PAL and SECAM television standards.
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.
AAC - Advanced audio coder. An audio-encoding standard for MPEG-2 that is not backward-compatible with MPEG-1 audio.
AC - Alternating current. An electric current that regularly reverses direction. Adopted as a video term for a signal of non-zero frequency. Compare to DC.
AC-3 - The former name of the Dolby Digital audio-coding system, which is still technically referred to as AC-3 in standards documents. AC-3 is the successor to Dolby’s AC-1 and AC-2 audio coding techniques.
access time - The time it takes for a drive to access a data track and begin transferring data. In an optical jukebox, the time it takes to locate a specific disk, insert it in an optical drive, and begin transferring data to the host system.
ADPCM - Adaptive differential pulse code modulation. A compression technique which encodes the difference between one sample and the next. Variations are lossy and lossless.
Advanced Optical Disc (AOD) - AOD and Blu-ray are similar in that they both use 405nm-wavelength blue-violet laser technology. while Blu-ray has a storage capacity of 25GB on a single-layer disc, AOD has a storage capacity of 20GB on a single-layer disc. and the capacity to hold 30GB on a dual-layer disc. AOD was developed jointly by Toshiba and NEC.
AES - Audio Engineering Society.
AES/EBU - A digital audio signal transmission standard for professional use, defined by the Audio Engineering Society and the European Broadcasting Union. S/P DIF is the consumer adaptation of this standard.
AGC - Automatic gain control. A circuit designed to boost the amplitude of a signal to provide adequate levels for recording. Also see Macrovision.
AMGM_VOBS - Video Object Set for Audio Manager Menu.
Amaray Case - Standard DVD video case.
analog - A signal of (theoretically) infinitely variable levels. Compare to digital.
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.
ANSI - American National Standards Institute.
AOTT_AOBS - Audio Object Set for Audio Only Title.
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.
ASF - Refers to Advanced Streaming Format, which is a streaming multimedia file format developed by Microsoft. It is an integral part of Windows 98 and Windows 2000, which will eventually replace the AVI format.
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.
ATSC - Advanced Television Systems Committee. In 1978, the Federal Communications Commission (FCC) empaneled the Advisory Committee on Advanced Television Service (ACATS) as an investigatory and advisory committee to develop information that would assist the FCC in establishing an advanced broadcast television (ATV) standard for the United States. This committee created a subcommittee, the ATSC, to explore the need for and to coordinate development of the documentation of Advanced Television Systems. In 1993, the ATSC recommended that efforts be limited to a digital television system (DTV), and in September 1995 issued its recommendation for a Digital Television System standard, which was approved with the exclusion of compression format constraints (picture resolution, frame rate, and frame sequence).
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, dvd 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.
B picture (or B frame) - One of three picture types used in MPEG video. B pictures are bidirectionally predicted, based on both previous and following pictures. B pictures usually use the least number of bits. B pictures do not propagate coding errors since they are not used as a reference by other pictures.
bit rate: the number of bits per second. higher rates translates to higher video quality. lower bit rates translates to lower video quality however allowing for longer run times as well as for the cds to be able to play on older computers.
bitstream - Digital data, usually encoded, designed to be processed sequentially and continuously.
BLER - Block error rate. A measure of the average number of raw channel errors when reading or writing a disc.
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.
blocking - A term referring to the occasional blocky appearance of compressed video (an artifact). Caused when the compression ratio is high enough that the averaging of pixels in 8 x 8 blocks becomes visible.
Blu-ray Disc (BD) - uses a 405nm-wavelength blue-violet laser technology, in contrast to the 650nm-wavelength red laser technology used in traditional DVD formats. The rewritable Blu-ray disc, with a data transfer rate of 36Mbps (1x speed) can hold up to 25GB of data on a single-layer disc and 50GB on a dual-layer disc. On a 50GB disc, this translates into 9 hours of high-definition (HD) video or approximately 23 hours of standard-definition (SD) video. The Blu-ray format was developed jointly by Sony, Samsung, Sharp, Thomson, Hitachi, Matsushita, Pioneer and Philips, Mistubishi and LG Electronics.
Book A - The document specifying the DVD physical format (DVD-ROM). Finalized in August 1996.
Book B - The document specifying the DVD-Video format. Mostly finalized in August 1996.
Book C - The document specifying the DVD-Audio format.
Book D - The document specifying the DVD record-once format (DVD-R). Finalized in August 1997.
Book E - The document specifying the rewritable DVD format (DVD-RAM). Finalized in August 1997.
bps - Bits per second. A unit of data rate.
brightness - Defined by the CIE as the attribute of a visual sensation according to which area appears to emit more or less light. Loosely, the intensity of an image or pixel, independent of color; that is, its value along the axis from black to white.
burst - A short segment of the color subcarrier in a composite signal, inserted to help the composite video decoder regenerate the color subcarrier.
B-Y, R-Y - The general term for color-difference video signals carrying blue and red color information, where the brightness (Y) has been subtracted from the blue and red RGB signals to create B-Y and R-Y color-difference signals.
byte - A unit of data or data storage space consisting of eight bits, commonly representing a single character. Digital data storage is usually measured in bytes, kilobytes, megabytes, and so on.
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.
capturing: the process in which video is transferred into a digital file for encoding. Video capture is an essential step video encoding and for video transfer to dvd.
CAV - Constant angular velocity. Refers to rotating disc systems in which the rotation speed is kept constant, where the pickup head travels over a longer surface as it moves away from the center of the disc. The advantage of CAV is that the same amount of information is provided in one rotation of the disc. Contrast with CLV and ZCLV.
Cb, Cr - The components of digital color-difference video signals carrying blue and red color information, where the brightness (Y) has been subtracted from the blue and red RGB signals to create B-Y and R-Y color-difference signals.
CBEMA - Computer and Business Equipment Manufacturers Association.
CBR - Constant bit rate. Data compressed into a stream with a fixed data rate. The amount of compression (such as quantization) is varied
to match the allocated data rate, but as a result quality may suffer during high compression periods. In other words, data rate is held constant while quality is allowed to vary. Compare to VBR.
CCI - Copy control information. Information specifying if content is allowed to be copied.
CCIR Rec. 601 - A standard for digital video. The CCIR changed its name to ITU-R, and the standard is now properly called ITU-R BT.601.
CD+G - Compact disc plus graphics. A variation of CD which embeds graphical data in with the audio data, allowing video pictures to be displayed periodically as music is played. Primarily used for karaoke.
CD-i - Compact disc interactive. An extension of the CD format designed around a set-top computer that connects to a TV to provide interactive home entertainment, including digital audio and video, video games, and software applications. Defined by the Green Book standard.
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.
CEMA - Consumer Electronics Manufacturers Association. A subsidiary of the Electronics Industry Association (EIA).
CGMS - Copy guard management system. A method of preventing copies or controlling the number of sequential copies allowed. CGMS/A is added to an analog signal (such as line 21 of NTSC). CGMS/D is added to a digital signal, such as IEEE 1394.
chapter - In DVD-Video, a division of a title. Technically called a part of title (PTT).
chroma (C´) - The nonlinear color component of a video signal, independent of the luma. Identified by the symbol C´ (where ´ indicates nonlinearity) but usually written as C because it’s never linear in practice.
chroma subsampling - Reducing color resolution by taking fewer color samples than luminance samples.
chrominance (C) - The color component (hue and saturation) of light, independent of luminance. Technically, chrominance refers to the linear component of video, as opposed to the transformed nonlinear chroma component.
CIE - Commission Internationale de l’Éclairage/International Commission on Illumination.
CIF - Common intermediate format. Video resolution of 352x288.
Cinepak - A popular compression/decompression technology or codec for computer video developed by Radius, Inc. (a.k.a. Digital Origin.)
CIRC - Cross-interleaved Reed Solomon code. An error-correction coding method which overlaps small frames of data.
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.
CLUT - Color lookup table. An index that maps a limited range color values to a full range of values such as RGB or YUV.
CLV - Constant linear velocity. Refers to a rotating disc system in which the head moves over the disc surface at a constant velocity, requiring that the motor vary the rotation speed as the head travels in and out. The further the head is from the center of the disc, the slower the rotation. The advantage of CLV is that data density remains constant, optimizing use of the surface area. Contrast with CAV and ZCLV.
CMF - Cutting master format. Specification for storing information needed for full DVD mastering (including CSS protection) in the control area of a DVD-R(A) disc. See also DDP.
CMI - Content management information. General information about copy protection and allowed use of protected content. Includes CCI.
Codec - Short for "compressor/decompressor", codec is any technology for compressing and decompressing data. Popular codecs for computer video include MPEG (also a file format), Indeo and Cinepak.
color 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).
color 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.
colorburst - See burst.
colorist - The title used for someone who operates a telecine machine to transfer film to video. Part of the process involves correcting the video color to match the film.
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.
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. Most televisions and VCRs have composite video connectors, which are usually colored yellow.
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.
constant data rate or constant bit rate - See CBR.
contrast - The range of brightness between the darkest and lightest elements of an image.
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.
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.
CVBS - Composite video baseband signal. Standard single-wire video, mixing luma and chroma signals together.
DAC - Digital-to-analog converter. Circuitry that converts digital data (such as audio or video) to analog data.
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.
dB - See decibel.
DBS - Digital broadcast satellite. The general term for 18-inch digital satellite systems.
DCT - Discrete cosine transform. An invertible, discrete, orthogonal transformation. Got that? A mathematical process used in MPEG video encoding to transform blocks of pixel values into blocks of spatial frequency values with lower-frequency components organized into the upper-left corner, allowing the high-frequency components in the lower-right corner to be discounted or discarded. Also digital component technology, a videotape format.
DDP - Disc description protocol. A specification for storing all the information needed to master a DVD (including CSS protection) on a DLT.
DDWG Digital Display Working Group - (see DVI).
decibel (dB) - A unit of measurement expressing ratios using logarithmic scales related to human aural or visual perception. Many different measurements are based on a reference point of 0 dB; for example a standard level of sound or power.
decimation - A form of subsampling which discards existing samples (pixels, in the case of spatial decimation, or pictures, in the case of temporal decimation). The resulting information is reduced in size but may suffer from aliasing.
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.
digitize - To convert analog information to digital information by sampling.
Digital Video - To capture, manipulate and store video in digital formats. A DV or digital video camcorder, for example, is a video camera that captures and stores images on a digital medium such as a DAT.
DIN - Deutsches Institut für Normung/German Institute for Standardization
DirectShow - A software standard developed by Microsoft for playback of digital video and audio in the Windows operating system. Replaces the older MCI and Video for Windows software.
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.
discrete cosine transform (DCT) - An invertible, discrete, orthogonal transformation. A mathematical process used in MPEG video encoding to transform blocks of pixel values into blocks of spatial frequency values with lower-frequency components organized into the upper-left corner, allowing the high-frequency components in the lower-right corner to be discounted or discarded.
discrete surround sound - Audio in which each channel is stored and transmitted separate from and independent of other channels. Multiple independent channels directed to loudspeakers in front of and behind the listener allow precise control of the soundfield in order to generate localized sounds and simulate moving sound sources.
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 - Short for Digital video express, a new DVD-ROM format promoted by several large Hollywood companies. With Divx, a movie (or other data) loaded onto a DVD-ROM is playable only during a specific time frame, typically two days.
double sided dual disc = dvd-5 & cd glued together.
dlt: digital linear tape or dlt is the preferred method for getting formatted dvds to the lab for the creation of a glass master; especially for discs requiring css, macro vision or ripgaurd.
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.
downsampling - See subsampling.
DRC - See dynamic range compression.
DSD - Direct Stream Digital. An uncompressed audio bitstream coding method developed by Sony. An alternative to PCM. Used by SACD.
DSI - Data search information. Navigation and search information contained in the DVD-Video data stream. DSI and PCI together make up an overhead of about 1 Mbps.
DSP - Digital signal processor (or processing).
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.
DV - Digital Video. Usually refers to the digital videocassette standard developed by Sony and JVC.
DVB - Digital video broadcast. A European standard for broadcast, cable, and digital satellite video transmission.
DVC - Digital video cassette. Early name for DV.
DVCAM - Sony’s proprietary version of DV.
DVCD - Double Video Compact Disc. Long-playing (100-minute) variation of VCD.
DVCPro - Matsushita’s proprietary version of DV.
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 can record data only once and then the data becomes permanent on the disc. The disc can not be recorded onto a second time.
DVD+RW is a re-recordable format similar to CD-RW. The data on a DVD+RW disc can be erased and recorded over numerous times without damaging the medium. DVDs created by a +R/+RW device can be read by most commercial DVD-ROM players.
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-R, DVD-RW and DVD-RAM - These formats are supported by Panasonic, Toshiba, Apple Computer, Hitachi, NEC, Pioneer, Samsung and Sharp. These formats are also supported by the DVD Forum.
DVD-R - is a recordable DVD format similar to CD-R and DVD+R. A DVD-R can record data only once and then the data becomes permanent on the disc. The disc cannot be recorded onto a second time. There also are two additional standards for DVD-R disks: DVD-RG for general use, and DVD-RA for authoring, which is used for mastering DVD video or data and is not typically available to the general public.
DVD-RW is a re-recordable format similar to CD-RW or DVD+RW. The data on a DVD-RW disc can be erased and recorded over numerous times without damaging the medium.DVDs created by a -R/-RW device can be read by most commercial DVD-ROM players.
DVD-RAM discs can be recorded and erased repeatedly but are compatible only with devices manufactured by the companies that support the DVD-RAM format. DVD-RAM discs are typically housed in cartridges.DVD+R DL and DVD-R DLDual layer technology is supported by a range of manufacturers including Dell, HP, Verbatim, Philips, Sony, Yamaha and others. As the name suggests, dual layer technology provides two individual recordable layers on a single-sided DVD disc.
DVD+R DL (also called DVD+R9) is a Dual Layer writeable DVD+R.DVD-R DL (also called DVD-R9) is a Dual Layer writeable DVD-R. The dual layered discs can hold 7.95GBThe dual layered discs (DVD+R9 and DVD-R9) can hold 7.95GB and double sided dual layer (called dvd-18) can hold 15.9GB.
DVD-ROM - DVD-ROM was the first DVD standard to hit the market and is a read-only format. The video or game content is burned onto the DVD once and the DVD will run on any DVD-ROM-equipped device. DVD-ROMs are similar to CDs.Non-standardized DVD formats.
dvd authoring: refers to the process of conceptual interactive design, menu design, capturing & encoding video, editing, setting chapter markers, formatting, finalizing and masetering. Dvd authoring usually refers to video transfer to dvd using a specialized industry standard application to create a finished dvd.
dvd copy protection: macro vision,css and ripigaurd make copying your dvd difficult. double sided dvds: is the term for two disks glued together; both sides are readable/playable. this format is generally used to offer global consumers both pal and ntsc formatted versions of the dvd program.
DVD Player One of the best features of DVD-ROM drives is that they are backward-compatible with CD-ROMs. This means that DVD-ROM players can play old CD-ROMs, CD-I disks, and video CDs, as well as new DVD-ROMs. Newer DVD players can also read CD-R disks
dvd-5 = 4.7 giga bytes is the standard memory
capacity and will hold approx. 2-3 hours of video.
dvd-9 = 8.54 giga bytes is the larger dual layered
format and will hold about 3-5 hours of video.
dvd-10 = double sided dvd-5.
dvd-18 = double sided dvd-9.
hd-dvd = single sided 15gb.
hd-dvd = double sided 30gb.
DVD-VCD is a DVD-Video disc that has data on it that has been encoded by using the MPEG-1 video format with the same definitions VCD has.
DVD-SVCD is also not a valid DVD standard, since the DVD standard does not support the SVCD resolution. The term DVD-SVCD is used to describe a hacked, or non-standard DVD-Video disc that has SVCD compatible content on it.DVD-MP3 is created with and contains only digital audio files in the MP3 format. Not all DVD players can play DVD-MP3 discs.
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.
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.
EBU - European Broadcasting Union.
ECC - See Error correction code.
ECD - Error-detection and correction code. See error-correction code.
ECMA - European Computer Manufacturers Association.
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.
EIA - Electronics Industry Association.
elementary stream - A general term for a coded bitstream such as audio or video. Elementary streams are made up of packs of packets.
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.
entropy coding - Variable-length, lossless coding of a digital signal to reduce redundancy. MPEG-2, DTS and Dolby Digital apply entropy coding after the quantization step. MLP also uses entropy coding.
EQ - Equalization of audio.
ETSI - European Telecommunications Standards Institute.
field - A set of alternating scan lines in an interlaced video picture. A frame is made of a top (odd) field and a bottom (even) field.
filter - (verb) To reduce the amount of information in a signal. (noun) A circuit or process that reduces the amount of information in a signal. Analog filtering usually removes certain frequencies. Digital filtering (when not emulating analog filtering) usually averages together multiple adjacent pixels, lines, or frames to create a single new pixel, line, or frame. This generally causes a loss of detail, especially with complex images or rapid motion. See letterbox filter. Compare to interpolate.
fixed rate - Information flow at a constant volume over time. See CBR.
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 doubler - A video processor that increases the frame rate (display rate) in order to create a smoother-looking video display. Compare to line doubler.
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.
glass master: a glass disk that contains the final dvd data and then is used as the stamper for mass replication.
GOP - Group of pictures. In MPEG video, one or more I pictures followed by P and B pictures. A GOP is the atomic unit of MPEG video access. GOPs are limited in DVD-Video to 18 frames for 525/60 and 15 frames for 625/50.
gray market - Dealers and distributors who sell equipment without proper authorization from the manufacturer.
H/DTV - High-definition/digital television. A combination of acronyms that refers to both HDTV and DTV systems.
Half D1 - MPEG-2 picture resolution of 352 x 480 (NTSC) or 352 x 576 (PAL/SECAM). See HHR.
HAVi - A consumer electronics industry standard for interoperability between digital audio and video devices connected via a network in the consumer’s home.
HDCD - High-definition Compatible Digital. A proprietary method of enhancing audio on CDs.
HD-DVD - Short for high definition-DVD, a generic term for the technology of recording high-definition video on a DVD. In general, HD-DVD is capable of storing between two and four times as much data as standard DVD. The two most prominent competing technologies are Blu-ray and AOD.
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.
HQ-VCD - High-quality Video Compact Disc. Developed by the Video CD Consortium (Philips, Sony, Matsushita and JVC) as a successor to VCD. Evolved into SVCD.
HRRA - Home Recording Rights Association.
hue - The color of light or of a pixel. The property of color determined by the dominant wavelength of light.
Huffman coding - A lossless compression technique of assigning variable-length codes to a known set of values. Values occurring most frequently are assigned the shortest codes. MPEG uses a variation of Huffman coding with fixed code tables, often called variable-length coding (VLC).
I picture (or I frame) - In MPEG video, an intra picture that is encoded independent from other pictures (see intraframe). Transform coding (DCT, quantization, and VLC) is used with no motion compensation, resulting in only moderate compression. I pictures provide a reference point for dependent P pictures and B pictures and allow random access into the compressed video stream.
IDTV - Improved-definition television. A television receiver that improves the apparent quality of the picture from a standard video signal by using techniques such as frame doubling, line doubling, and digital signal processing.
IFE - In-flight entertainment.
I-MPEG - Intraframe MPEG. An unofficial variation of MPEG video encoding that uses only intraframe compression. I-MPEG is used by DV equipment.
Indeo - A codec for compressing and decompressing video developed by Intel Corporation.
interframe - Something that occurs between multiple frames of video. Interframe compression takes temporal redundancy into account. Contrast with intraframe.
interlace - A video scanning system in which alternating lines are transmitted, so that half a picture is displayed each time the scanning beam moves down the screen. An interlaced frame is made of two fields.
interpolate - To increase the pixels, scan lines, or pictures when scaling an image or a video stream by averaging together adjacent pixels, lines, or frames to create additional inserted pixels or frames. This generally causes a softening of still images and a blurriness of motion images because no new information is created. Compare to filter.
intraframe - Something that occurs within a single frame of video. Intraframe compression does not reduce temporal redundancy, but allows each frame to be independently manipulated or accessed. Compare to interframe.
inverse telecine - The reverse of 3:2 pulldown, where the frames which were duplicated to create 60-fields/second video from 24-frames/second film source are removed. MPEG-2 video encoders usually apply an inverse telecine process to convert 60-fields/second video into 24-frames/second encoded video. The encoder adds information enabling the decoder to recreate the 60-fields/second display rate.
ISO - International Organization for Standardization.
ITU-R BT.601 - The international standard specifying the format of digital component video. Currently at version 5 (identified as 601-5)
JCIC - Joint Committee on Intersociety Coordination.
jewel case - The plastic clamshell case that holds a CD or DVD.
jitter - Temporal variation in a signal from an ideal reference clock. There are many kinds of jitter, including sample jitter, channel jitter, and interface jitter.
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.
lead in - The physical area 1.2 mm or wider preceding the data area on a disc. The lead in contains sync sectors and control data including disc keys and other information.
lead out - On a single-layer disc or PTP dual-layer disc, the physical area 1.0 mm or wider toward the outside of the disc following the data area. On an OTP dual-layer disc, the physical area 1.2 mm or wider at the inside of the disc following the recorded data area (which is read from the outside toward the inside on the second layer).
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.
level - In MPEG-2, levels specify parameters such as resolution, bit rate, and frame rate. Compare to profile.
line doubler - A video processor that doubles the number of lines in the scanning system in order to create a display with scan lines that are less visible. Some line doublers convert from interlaced to progressive scan.
linear PCM - A coded representation of digital data that is not compressed. Linear PCM spreads values evenly across the range from highest to lowest, as opposed to nonlinear (companded) PCM which allocates more values to more important frequency ranges.
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.
Lo/Ro - Left only/right only. Stereo signal (no matrixed surround information). Optional downmixing output in Dolby Digital decoders. Does not change phase, simply folds surround channels forward into Lf and Rf.
locale - See regional code.
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.
lossless compression - Compression techniques that allow the original data to be recreated without loss. Contrast with lossy compression.
lossy compression - Compression techniques that achieve very high compression ratios by permanently removing data while preserving as much significant information as possible. Lossy compression includes perceptual coding techniques that attempt to limit the data loss to that which is least likely to be noticed by human perception.
LP - Long-playing record. An audio recording on a plastic platter turning at 33 1/3 rpm and read by a stylus.
LPCM - See linear PCM.
Lt/Rt - Left total/right total. Four surround channels matrixed into two channels. Mandatory downmixing output in Dolby Digital decoders.
luma (Y´) - The brightness component of a color video image (also called the grayscale, monochrome, or black-and-white component). Nonlinear luminance. The standard luma signal is computed from nonlinear RGB as Y´ = 0.299 R´ + 0.587 G´ + 0.114 B´.
luminance (Y) - Loosely, the sum of RGB tristimulus values corresponding to brightness. May refer to a linear signal or (incorrectly) a nonlinear signal.
macroblock - In MPEG MP@ML, the four 8 x 8 blocks of luma information and two 8 x 8 blocks of chroma information form a 16 x 16 area of a video frame.
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.
main level (ML) - A range of proscribed picture parameters defined by the MPEG-2 video standard, with maximum resolution equivalent to ITU-R BT.601 (720 x 576 x 30).
main profile (MP) - A subset of the syntax of the MPEG-2 video standard designed to be supported over a large range of mainstream applications such as digital cable TV, DVD, and digital satellite transmission.
matrix encoding - The technique of combining additional surround-sound channels into a conventional stereo signal. Also see Dolby Surround.
matte - An area of a video display or motion picture that is covered (usually in black) or omitted in order to create a differently shaped area within the picture frame.
megapixel - A term referring to an image or display format with a resolution of approximately 1 million pixels.
menu: with most authored dvds there are two kinds of menus: static menus and motion menus. dvd video: mpeg 2 is the standard video encoding format.
Millennium Group - The group of companies proposing the Galaxy watermarking format. (Macrovision, Philips, Digimarc)
mini DVD - 1) Small size (8-cm) DVD. 2) DVD-Video content stored on a CD (or CD-R/RW). Less ambiguously called cDVD.
MLP (Meridian Lossless Packing) - A lossless compression technique (used by DVD-Audio) that removes redundancy from PCM audio signals to achieve a compression ratio of about 2:1 while allowing the signal to be perfectly recreated by the MLP decoder.
Morphing - Morphing refers to an animation technique in which one image is gradually turned into another.
mosquitoes - A term referring to the fuzzy dots that can appear around sharp edges (high spatial frequencies) after video compression. Also known as the Gibbs Effect.
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
motion compensation - In video decoding, the application of motion vectors to already-decoded blocks to construct a new picture.
motion estimation - In video encoding, the process of analyzing previous or future frames to identify blocks that have not changed or have only changed location. Motion vectors are then stored in place of the blocks. This is very computation-intensive and can cause visual artifacts when subject to errors.
Motion-JPEG This is an extension of JPEG, which is a standard for storing and compressing digital images. In motion-JPEG, each frame in the video is stored with the JPEG format.
motion vector - A two-dimensional spatial displacement vector used for MPEG motion compensation to provide an offset from the encoded position of a block in a reference (I or P) picture to the predicted position (in a P or B picture).
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.
multiplexing - Combining multiple signals or data streams into a single signal or stream. Usually achieved by interleaving at a low level.
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
mux - Short for multiplex.
mux_rate - In MPEG, the combined rate of all packetized elementary streams (PES) of one program. The mux_rate of DVD is 10.08 Mbps.
NAB - National Association of Broadcasters.
NCTA - National Cable Television Association.
nighttime mode - Name for Dolby Digital dynamic range compression feature to allow low-volume nighttime listening without losing legibility of dialog.
noise floor - The level of background noise in a signal or the level of noise introduced by equipment or storage media below which the signal can’t be isolated from the noise.
noise - Irrelevant, meaningless, or erroneous information added to a signal by the recording or transmission medium or by an encoding/decoding process. An advantage of digital formats over analog formats is that noise can be completely eliminated (although new noise may be introduced by compression).
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.
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.
overscan - The area at the edges of a television tube that is covered to hide possible video distortion. Overscan typically covers about 4 or 5 percent at the edges of the picture but can cover as much as 10 percent.
P picture (or P frame) - In MPEG video, a "predicted" picture based on difference from previous pictures. P pictures (along with I pictures) provide a reference for following P pictures or B pictures.
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.
Packet writing Packet writing software packages like Adaptec's DirectCD allow you to drag and drop files onto your CD-R or CD-RW discs, just like any other drive on your computer.
packetized elementary stream (PES) - The low-level stream of MPEG packets containing an elementary stream, such as audio or video.
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.
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.
PCM - 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.
PC-TV - The merger of television and computers. A personal computer capable of displaying video as a television.
perceived resolution - The apparent resolution of a display from the observer’s point of view, based on viewing distance, viewing conditions, and physical resolution of the display.
perceptual coding - Lossy compression techniques based on the study of human perception. Perceptual coding systems identify and remove information that is least likely to be missed by the average human observer.
PES (packetized elementary stream) - A single video or audio stream in MPEG format.
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).
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.
profile - In MPEG-2, profiles specify syntax and processes such as picture types, scalability, and extensions. Compare to level.
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).
progressive scan - A video scanning system that displays all lines of a frame in one pass. Contrast with interlaced scan.
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. Contrast with OTP.
QCIF - Quarter common intermediate format. Video resolution of 176 x 144.
quantization levels - The predetermined levels at which an analog signal can be sampled as determined by the resolution of the analog-to-digital converter (in bits per sample); or the number of bits stored for the sampled signal.
QuickTime - A digital video software standard developed by Apple Computer for Macintosh (Mac OS) and Windows operating systems. QuickTime is used to support audio and video from a DVD.
QXGA - A video graphics resolution of 2048 x 1536.
raster - The pattern of parallel horizontal scan lines that makes up a video picture.
reference picture (or reference frame) - An encoded frame that is used as a reference point from which to build dependent frames. In MPEG-2, I pictures and P pictures are used as references.
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.
RSDL - Reverse-spiral dual-layer. See OTP.
R-Y, B-Y - The general term for color-difference video signals carrying red and blue color information, where the brightness (Y) has been subtracted from the red and blue RGB signals to create R-Y and B-Y color-difference signals.
S/N - Signal-to-noise ratio. Also called SNR.
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 (see resampling and subsampling).
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.
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.
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.
signal-to-noise ratio - The ratio of pure signal to extraneous noise, such as tape hiss or video interference. Signal-to-noise ratio is measured in decibels (dB). Analog recordings almost always have noise. Digital recordings, when properly prefiltered and not compressed, have no noise.
simple profile (SP) - A subset of the syntax of the MPEG-2 video standard designed for simple and inexpensive applications such as software. SP does not allow B pictures.
SMPTE - The Society of Motion Picture and Television Engineers. An international research and standards organization. The SMPTE time code, used for marking the position of audio or video in time, was developed by this group.
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.
spatial resolution - The clarity of a single image or the measure of detail in an image.
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).
squeezed video - See anamorphic.
stream - A continuous flow of data, usually digitally encoded, designed to be processed sequentially. Also called a bitstream.
Streaming - A technique for transferring a steady and continuous flow of data, such as video or audio, on the Internet. For streaming to work, the client receiving the data must be able to collect the data and send it as a steady stream to the application that is processing the data and converting it to pictures or sound. While this technology is becoming increasingly important with the growth of the Internet, most users do not have fast enough access to download large multimedia files that are currently better delivered by CDs and DVDs.
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. See chroma subsampling. Also called downsampling.
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. See subpicture.
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. Also called Y/C. 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.
sync - A video signal (or component of a video signal) containing information necessary to synchronize the picture horizontally and vertically. Also, specially formatted data on disc which helps the readout system identify location and specific data structures.
syntax - The rules governing construction or formation of an orderly system of information. For example, the syntax of the MPEG video encoding specification defines how data and associated instructions are used by a decoder to create video pictures.
system menu - The main menu of a DVD-Video disc, from which titles are selected. Also called the title selection menu or disc menu.
telecine artist - The operator of a telecine machine. Also called a colorist.
telecine - The process (and the equipment) used to transfer film to video. The telecine machine performs 3:2 pulldown by projecting film frames in the proper sequence to be captured by a video camera.
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 - 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 - 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.
tristimulus - A three-valued signal that can match nearly all colors of visible light in human vision. This is possible because of the three types of photoreceptors in the eye. RGB, YCbCr, and similar signals are tristimulus, and can be interchanged by using mathematical transformations (subject to possible loss of information).
TVL - Television line. See lines of horizontal resolution.
TWG - Technical working group. A usually ad-hoc group of representatives working together for a period of time to make recommendations or define standards.
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.
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.
VBR - Variable bit rate. Data that can be read and processed at a volume that varies over time. A data compression technique that produces a data stream between a fixed minimum and maximum rate. A constant level of compression is generally maintained, with the required bandwidth increasing or decreasing depending on the complexity (the amount of spatial and temporal energy) of the data being encoded. In other words, data rate is held constant while quality is allowed to vary. Compare to CBR.
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. (Constrast with universal DVD player.)
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 - A recording produced with a video camera, recorder or some other device that captures full motion.
Video Capture - The process of converting analog video signals into a digital format and then storing the digital video on a computer's mass storage device. Video capture from analog devices requires a special video capture card that converts the analog signals into digital form.
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 Editing This is a process to manipulate video images. Video editing includes cutting segments, re-sequencing clips, and adding transitions and other special effects.
Video for Windows - The system software additions used for motion video playback in Microsoft Windows. Replaced in newer versions of Windows by DirectShow (formerly called ActiveMovie).
Video manager (VMG) - The disc menu. Also called the title selection menu.
Video Standards There is a variety of video standards that define the resolution and colors for display, which are determined by both the monitor and by the video adapter. The monitor must be able to show the resolution and colors defined by the standard, and the video adapter must be capable of transmitting the appropriate signals to the monitor. More popular video standards for PCs are VGA (Video Graphics Array) and SVGA.
Video title set (VTS) - A set of one to ten files holding the contents of a title.
videophile - Someone with an avid interest in watching videos or in making video recordings. Videophiles are often very particular about audio quality, picture quality, and aspect ratio to the point of snobbishness.
VOB - Video object. A small physical unit of DVD-Video data storage, usually a GOP.
volume - A logical unit representing all the data on one side of a disc.
VSDA - Video Software Dealers Association.
WAEA - World Airline Entertainment Association. Discs produced for use in airplanes contain extra information in a WAEA directory. The in-flight entertainment working group of the WAEA petitioned the DVD Forum to assign region 8 to discs intended for in-flight use.
watermark - Information hidden as “invisible noise” or “inaudible noise” in a video or audio signal.
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.
XGA - A video graphics resolution of 1024 x 768 pixels.
XVCD - A non-standard variation of VCD.
Y - The luma or luminance component of video: brightness independent of color.
Y/C - A video signal in which the brightness (luma, Y) and color (chroma, C) signals are separated. Also called s-video.
YCbCr - A component digital video signal containing one luma and two chroma components. The chroma components are usually adjusted for digital transmission according to ITU-R BT.601. DVD-Video’s MPEG-2 encoding is based on 4:2:0 sYCbCr signals. YCbCr applies only to digital video, but is often incorrectly used in reference to the YPbPr analog component outputs of DVD players.
YPbPr - A component analog video signal containing one luma and two chroma components. Often referred to loosely as YUV or Y, B-Y, R-Y.
YUV - In the general sense, any form of color-difference video signal containing one luma and two chroma components. Technically, YUV is applicable only to the process of encoding component video into composite video. See YCbCr and YPbPr.
ZCLV - Zoned constant linear velocity. Concentric rings on a disc within which all sectors are the same size. A combination of CLV and CAV