Glossary C-E

C
Cable Modem A high-speed connection to the Internet through a cable TV network.
Caddy On CD-ROM drives that do not have a slide-out tray to put CDs in, the CD has to be loaded into a caddy before it can be loaded; they are about the same size and shape as a jewel case.
Calibration Adjusting a video display to match a color standard (in the United States, this standard is NTSC). Also refers to adjusting audio levels against a standard to ensure that sound is being transmitted accurately.
CAM A bootleg video made by someone sneaking a video recorder into a movie theater. Members of the audience can often be seen and heard during playback.
Camera Angles See angle.
Caption An on-screen text version of the audio in a program, including dialogue, sound effects, speaker names and song titles.
Capture Recording TV/satellite signals onto a disc. Sometimes called “cap” or “capping.”
CAV Constant Angular Velocity. If a CD or DVD were to spin with constant angular velocity, the read/write head would be moving at a different linear speed near the center of the disc than it would at the outside edge. To keep the data read at a constant rate, the CD or DVD drive will begin to slow down the further away from the center the read/write head gets. In a CD player, for example, the rotation speed decreases from 495 rpm to 212 rpm. This change in speed gives the disc a constant linear velocity (CLV).
CBR Constant Bit Rate Compression. A CBR audio or video stream has the same bit rate throughout the length of the program, no matter how complex or simple it becomes. See Variable Bit Rate.
CD Bridge A Photo CD/Video CD specification for recording CD-I information onto a CD-ROM XA disc.
CD Extra (or CD Plus) A disc capable of holding both audio tracks and CD-ROM XA data tracks, recorded in separate sessions.
CD+G (or Karaoke) An audio CD with graphics and text stored in its subchannels. A special player makes the graphics and text (typically the lyrics to the audio tracks) visible during playback.
CD-DA Compact Disc-Digital Audio. The earliest version of the compact disc as we know it today, developed by Philips and Sony. The Red Book is the standard which CD-DA discs are recorded in.
CD-R Compact Disc-Recordable. Recordable write-once CDs.
CD-ROM Compact Disc-Read Only Memory. A compact disc used as memory media. The Yellow Book defines CD-ROM specifications.
CD-ROM Drive A computer drive that can read a CD-ROM. CD-ROM drives can also play audio CDs.
CD-ROM XA Compact Disc-Read Only Memory Extended Architecture. An extension of the Yellow Book standards that adds improved audio and video capabilities to CD-ROMs. Although no longer used as an independent format, CD-ROM XA is still used for Photo CDs.
CD-RW CD-ReWritable. A CD that can be erased and re-recorded. CD-RWs can only be written in CD-RW drives.
Cell A small portion of a chapter on a DVD, the most basic unit used for navigational purposes.
Center Channel In a surround-sound system, the center channel is located directly in front of the user.
Center Speaker The speaker that the center channel is heard from. Dialogue, sound effects and centrally positioned music normally come out of this speaker.
CGMS Content Guard Management System. Copy protection for DVDs that will permit a limited number of copies to be made.
Channel A single audio track. For example, 6.1 Channel Surround Sound is made of seven channels: left, middle, right, rear left, rear right, rear center and one subwoofer.
Chapter Similar to a track on an audio CD, a chapter is a subdivision of a DVD, usually a single scene from a movie. One DVD can hold up to 999 separate chapters.
Chroma Bug An artifact appearing as streaky/spiky horizontal lines on the chroma channel, most easily seen along diagonal edges. Although this bug has been around for a long time, it was never a problem with low-resolution TV sets. Now that HDTV is becoming more widespread, awareness of the bug is also spreading.
Chroma Key See Blue Screen Process.
Chroma Noise Random noise appearing in large areas of a single color on a screen, particularly blue. This problem is becoming less common: digital video processing doesn’t suffer from it like analog video does.
Chrominance The color component of a video signal that includes information about hue and saturation.
Cinema Craft Encoder A high-quality software encoder; Cinema Craft SP is the most widely used version.
CinemaScope 20th Century Fox’s anamorphic film process.
Clamping Area The innermost area of a disc which is gripped by a CD/DVD player in order to spin the disc.
Close Disc A finalization process performed on a recordable disc so that no further data can be written to it.
Close Session Once a disc recording session is closed, information about the session is written into the disc’s table of contents, and lead-in/lead-out tracks are written, preparing the disc for use in another session.
Closed Captions A signal embedded in a video which is decoded during playback and produces on-screen subtitles for the hearing impaired.
Closed GOP An MPEG encoding method which begins with an I frame and does not rely on I or P frames from a previous GOP to produce B frames.
CLV Constant Linear Velocity. See CAV (Constant Angular Velocity).
Coaster A ruined DVD or CD that can be used as a drink coaster.
Coaxial A/V Connection An RF connection for a video signal; DVD players have coaxial outputs which do not require separate audio/video inputs.
Coaxial Connection A consumer-level digital audio connection, using an RCA jack. The coaxial cable is an impedance-constant two-conductor cable which can have either a stranded or a solid core.
Codec A software driver that compresses and decompresses audio or video which is being digitized from an analog source. Well-known codecs include DivX, MPEG-1, MPEG-2 and MP3.
Color Temperature The value of a light source color in degrees Kelvin (K). Lower temperatures are reddish, while higher temperatures are bluer. A properly calibrated display device is set at 6500 degrees Kelvin.
ColorStream Component video connections for Toshiba DVD players and TV sets.
Combo Drive A DVD-ROM, DVD-R, DVD-RW or DVD+RW drive that can read and write CD-R and CD-RW discs.
Component Video Video signals, either digital or analog, that are broken up into their component parts: red/green/blue (RGB) or chroma/color difference (YCbCr, YPbPr, YUV). Component video is the highest quality signal, superior to S-video and composite video. It is mainly used at the professional level of video production; most consumer electronics do not have component video inputs.
Component Video Output A set of three RCA or BNC connectors for transferring component video signals.
Composite Output The consumer-level RF signal; all DVD players use this output since most TVs lack S-video or component video inputs.
Composite Video An analog signal that combines all the luminance and chrominance components, transmitting them through a single cable. Most TVs, VCRs and DVD players have composite input/output connectors.
Compress Converting audio and video data into a compact form for storage or transmission.
Compression Removing redundancies in data to reduce the amount of data being stored or transmitted. Lossless compression keeps the removal to an absolute minimum to maximize the completeness of the data; lossy compression sacrifices as much data as possible in order to maximize compression.
Connector The terminating end of a cable.
Contrast The range between the lightest and darkest tones in an image.
Convert To change media from one format into another.
Copy Protection Any method, either physical or software-based, of preventing illegal duplication of audio programs, video programs and computer software.
Coring A form of video noise reduction that adjusts or removes details which fall below certain thresholds.
Crop Removing segments of a video stream.
CSS Content Scrambling System. A form of digital copy protection for DVDs that periodically scrambles the data on a disc using an encryption algorithm.
D
D1 A video resolution standard; in the NTSC system, full D1 is 720 × 480 pixels, while the PAL/SECAM version of full D1 is 720 × 576.
DAC Digital to Analog Converter. A device that converts digital signals into analog signals.
DAT Digital Audio Tape.
Data Area The space on a disc where data is written. Other areas of the disc are reserved for lead-in/lead-out, clamping and labels.
Data Rate The speed at which data is read, measured in kilobytes per second (kbps).
DCT Discrete Cosine Transform. A somewhat lossy MPEG compression algorithm that increases the efficiency of entropy coding.
DDP Disc Description Protocol. A small file on a disc that tells how to master data image files.
Decode Decompressing a video clip and converting its color space of from YUV to RGB.
Decoder A device that decodes compressed audio or video and reproduces the original information.
Decompress Converting compacted video and audio data back into its original form.
Deinterlace Creating a single video frame from two interlaced fields. Necessary when creating a still frame or when using video at a different rate than the one it was originally recorded at.
Deleted Scenes Scenes cut from a program due to time constraints or technical problems (“bloopers”). Some DVDs put these scenes back into a film and re-release it as an “extended” or “director’s” cut.
Delta Frame A frame that only contains data that has changed since the previous frame (an efficient compression method).
Demultiplex (or Demux) Splitting audio and video into separate files.
Descriptive Video Service An optional language track for the visually impaired that describes what’s happening on the screen.
Digital Audio Extraction Copying CD-DA audio tracks to a hard disk or recordable digital media.
Digital Comb Filter Converting chrominance and luminance signals into digital format for enhanced color purity and reduced dot crawl.
Digital Output Coaxial/optical output on a DVD player for sending a Dolby Digital bitstream to a Dolby Digital decoder.
Digital Video A video signal made up of binary numbers (0s and 1s) that describe color and brightness.
Digital8 Camcorder format that can record digital-quality video onto Hi8 or 8mm tape. Many Digital8 camcorders can play back analog Hi8 and 8mm tapes, although they cannot record in these formats.
Digitize Converting analog signals to digital.
Dipole Speaker A loudspeaker with two drivers that radiate in opposite directions and are 180 degrees out of phase with each other, producing diffuse surround sound.
Direct View A display device with a picture tube, like a standard TV set, instead of front/rear projection.
Directory Structure A Book B-specification defining file sets that must be present on all DVDs, such as Root and VIDEO_TS.
Disc Image One large file that represents an entire set of data and programs that will appear on a disc, including content and structure.
Disc-at-Once Recording multiple tracks on a CD in a single operation and then closing the disc without turning off the laser.
Discrete Surround Sound A sound system where multiple channels play independently of each other, such as Dolby Digital.
DiVA A Mac-based MPEG-1/MPEG-2 video converter, capable of handling a large number of video formats including QuickTime, MPEG and MOV.
DivX™ A video compression technology based on the MPEG-4 compression standard. It is an extremely efficient method of compression, able to compress an MPEG-2 video to one-tenth of its original size.
DivXHD DivX High Definition. Streaming video of incredible quality at one-fifth the bit rate of HDTV broadcasts.
DLT Digital Linear Tape. High-storage tape (type III or type IV, 10–20 Gb) used to create DVD masters.
Documentary “Behind-the-scenes” footage included on many DVDs, allowing viewers to learn about the production of a particular film.
Dolby Digital Multi-channel digital bitstreaming audio, where the different channels play independently of each other and at different frequencies to provide a full “surround sound” experience.
Dolby Digital EX See 6.1 Channel Surround Sound.
Dolby Digital THX EX See 7.1 Channel Surround Sound.
Dolby Pro Logic The consumer equivalent of a theater’s Dolby Stereo, it creates four variable-frequency sound channels from a two-channel source.
Dolby Pro Logic II Creates a simulated 5.1 Channel Surround Sound effect from a 4 Channel Dolby Surround signal. Backwards-compatible with already-existing Dolby Surround media.
Downmix A system’s ability to play mono, stereo or multi-channel surround sound from an encoded soundtrack.
Drop Frame Frames dropped out of black & white videos to match the broadcast speed of color video. Black & white broadcasts at 30 frames/second; color is a little slower at 29.97 frames/second. Over the course of one hour (3600 seconds) this discrepancy in speeds makes a program in black & white last

     ((30 f/s × 3600 seconds) – (29.97 f/s × 3600 seconds))
          = 108 frames, or

          108 frames ÷ 30 f/s = 3.6 seconds

longer than its color counterpart. To figure out which frames are dropped, the following standard is used:

  • In every minute of a black & white broadcast, of the ((30 f/s × 60 seconds) = 1,800) 1,800 frames shown, :00 and :01 are dropped, except in minutes divisible by 10.

Therefore, in one hour, two frames per minute are dropped a total of 54 times (every minute except for minutes 0, 10, 20, 30, 40, and 50), causing a total loss of 108 frames.

DSDL Double Sided Dual Layer. A DVD that can hold up to 17 GB of video, not supported by DVD-R/W or DVD+R/W.
DSI Data Search Information. Packets of control data recorded throughout a DVD, allowing for navigation, angle changes and seamless playback.
DSL Digital Subscriber Line. A broadband connection sent over copper wires; slightly slower than a cable modem, but faster than ISDN.
DSSL Double Sided Single Layer. A DVD that can hold up to 9.7 GB of video, supported by DVD-R/W and DVD+R/W.
DTS Digital Theater Systems Digital Sound. A six-channel audio compression format similar to Dolby Digital; however, it has a higher data rate than Dolby (four times higher, 1.44 Mbps), presumably giving it better sound quality. A decoder for this type of audio is not mandatory for all DVD players, so DTS has to “piggyback” on Dolby Digital or LPCM tracks if a DVD player does not have DTS playback capability.
DTS Surround EX See 6.1 Channel Surround Sound.
DTS THX Surround EX See 7.1 Channel Surround Sound.
DTV Digital Television. The U.S. ATSC digital standard includes standard-definition (SDTV) and high-definition (HDTV) digital formats. The picture and sound quality of HDTV is far superior to analog.
DV Digital Video. Video captured to a PC from a digital source, such as a digital camcorder. Usually stored as AVI files by one of two methods: type-1 and type-2. Type-1 combines audio and video into a single stream; they must be split by a filter in order to manipulate sound and picture separately. Type-2 digital video is made of one video stream and from one to four audio streams. These differences determine what kind of editing process can be performed on the footage. For example, type-1 video cannot be used with Video for Windows (VfW)-based editors.
DV Converter Converts analog video (such as VHS, S-VHS or 8mm) to DV.
DV Timecode (or DV Time) Another technical glitch caused by different frames-per-second rates between two formats (see drop frame). A DV Timecode has to be transferred on a separate FireWire cable during a dub or the time will slowly desynchronize.
DVB Digital Video Broadcasting. A set of digital video transmission standards created by the European Broadcast Union. There are several DVB standards, including:

  • DVB-S (Satellite)
  • DVB-C (Cable)
  • DVB-T (Terrestrial)
  • DVB-SI (Specification for Service Information)
  • DVB-CI (Common Interface for Conditional Access)
DVD Digital Video Disc (or Digital Versatile Disc). An optical storage disc capable of storing 4.7–17 GB of data. For videos/movies, DVD uses MPEG-2 video compression and either Dolby Digital or DTS audio.
DVD Changer A DVD player that can store two or more DVDs and switch between them, either automatically or according to a user-specified playlist.
DVD Studio Pro DVD authoring software from Apple for use on Power Mac G4 desktops (or better). It has an extremely simple user interface, allowing home video enthusiasts to produce their own high-quality DVDs.
DVD Video Filesystem A file system for DVD video that works in both the read-only and writable versions of the media.
DVD+R DVD+Recordable. A DVD that can be recorded to one time only.
DVD+R DL (or DVD+R9) DVD+Recordable Dual Layer. The same as DVD+R, only with a dual-layered disc.
DVD+RW DVD+ReWriteable. A DVD that can be re-recorded.
DVD±R An abbreviation for the DVD-R and DVD+R standards.
DVD-5 A single-sided, single-layer DVD.
DVD-9 A single-sided, dual-layer DVD.
DVD-10 A double-sided, single-layer DVD.
DVD-18 A double-sided, dual-layer DVD.
DVD-A DVD-Audio. A DVD with extremely high-quality audio tracks, including stereo and multi-channel sound. A DVD-A disc can also have videos or pictures on it, but the format is primarily for sound.
DVD-MP3 A DVD with MP3 audio files burned onto it. Although a large number of MP3 files can be stored on a DVD, playing them directly from DVD is more complicated, as there are very few DVD players that support the MP3 format.
DVD-R DVD-Recordable. A DVD that can be recorded to one time only.
DVD-R DL (or DVD-R9) DVD-Recordable Dual Layer. The same as DVD-R, only with a dual-layer disc.
DVD-RAM DVD-Random Access Memory. A type of rewriteable DVD with backwards-compatibility problems: DVD-ROM drives and DVD players can’t read them.
DVD-ROM DVD-Read Only Memory. Intended as a replacement for the CD-ROM for computers; however, in order to play DVD movies on a DVD-ROM drive, an MPEG-2 decoder is needed.
DVD-RW DVD-ReWritable. A rewriteable version of the DVD-R which can only be used to record video and audio.
DVD-SVCD SVCD (Super VideoCD) video on a DVDR/W. Although the DVD standard is not compatible with SVCD, resampling the audio (to 48 khz) may get it to work.
DVD-TV Combo A TV set with a DVD player built in.
DVD-VCD VCD (VideoCD) content on a DVDR/W; like DVD-SVCD, the audio needs to be resampled to 48 khz in order to work properly.
DVD-VHS Combo A DVD player and VHS video recorder in a single unit
DVD-Video DVD-Video is the “standard” video element of the DVD format.
DVD-VR Also known as DVD-RTRW for “real-time read/write.” Forward-only indexing allows disc images to be written immediately without having to create an indexed DVD video file.
DVI Digital Video Interface. A new digital transfer method designed to take advantage of high-quality LCD monitors and video cards, much faster than analog component video.
Dynamic Pan & Scan A set of instructions encoded on a wide-screen (16:9) DVD that will automatically crop the picture to fit a standard 4:3 screen. Not all DVD players handle this feature equally well, so its future is uncertain.
Dynamic Range The range of an audio signal’s loudest and quietest parts.
E
EAN (or Universal Product Code) A 13-digit catalog number for a CD which is written into the CD table of contents.
Easter Eggs A hidden feature on a DVD, accessed by hidden icons or a specific sequence of menu commands.
ECC/EDC Error Correction Code/Error Detection Code. Scrambled and redundant data added to a disc during recording, used to detect transmission errors and which can reconstruct data if a read error occurs.
ECC Constraint Length Interleaving sectors on a DVD so that physical defects are spread over a larger data area, which increases the chances of error correction codes being able to fix the problem.
Edge Enhancement A process performed when transferring film and video to DVD: it increases the contrast in the picture and helps clean up scratches and spots, but it can cause a chiseled or haloed look on high-contrast edges, and also destroys some of the fine tone in the image.
Elementary Stream There are two types of elementary streams: video (the output from an MPEG video encoder) and audio (the output of an audio encoder). These streams are converted into Video PES and Audio PES before they are combined into a single stream.
Encode To convert the color space of a video from RGB to YUV and then compressing it.
Encoding Changing data from one form into another in order to make it compatible with certain software/hardware or to compress it. MPEG-1, MPEG-2 and DivX are some video encoding methods; MP3, DTS and Dolby Digital are some audio encoding methods.
Entropy Coding (or variable length encoding or Huffman coding) A compression method in digital imaging and video which uses shorter bit patterns for more common characters and longer bit patterns for less common characters (as opposed to fixed length encoding which uses the same length bit pattern regardless of a character’s frequency).
Error Correction A circuit that corrects errors during the retrieving/decoding stage of a digital signal’s playback.
Extent A sequential group of sectors where a file (or part of a file) is recorded.
Extro A video clip at the end of a disc; “Change Disc” is a common extro at the end of a multi-volume disc set.

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