Curriculum Corporation
Video Research Project

Glossary

3G
ADSL Abbreviation for Asynchronous Digital Subscriber Line. A type of broadband high-speed Internet connection technology that enables ‘real-world’ connection speeds of 25KB/sec to 100KB/sec or more. That is, five to 20 times faster than standard dial-up connection. ADSL piggy-backs on a normal phone line, allowing the phone to be used for voice calls while connected to the Internet. ADSL is not available in all areas.
Authoring Simply placing MPEG2 video files on a DVD-ROM is insufficient to enable the disc to be played in a conventional DVD player. The disc must be authored. This means the information must be burnt to disc in a very specific format to comply with the official DVD standard. In this way playback on any domestic DVD can be assured. Basic DVD authoring software is generally included with DVD burners.
Bandwidth The bandwidth of a communications connection refers to the speed at which data can be moved over it. Dial-up modem speeds reach 56Kbps or 56,000 bits per second. ADSL services begin at 256Kbps. Typical Ethernet LAN (local area network) connections are 11Mbps or 11,000,000 bit per second or greater.
Betacam SP A professional broadcast quality analogue videotape format introduced by Sony in 1986. Betacam SP uses half-inch tape and is popular for the acquisition of news footage and in professional video production.
Binary Our normal decimal numbering system has 10 digits from zero to nine. The binary system has only two digits, zero and one. This is convenient for computers as a number can be represented simply as the absence (zero) or presence (one) of an electric charge in the computer’s circuitry. See also bit, Byte, Gigabyte and Megabyte.
Bit A single digit in the binary number system, either a zero or a one. See also the related larger units of Byte, Gigabyte and Megabyte.
Broadband A faster than dial-up Internet connection such as ADSL or cable modem.
Byte A sequence of eight binary digits (bits). For example, 11111110 (which in the normal decimal system is 254). There are 2^8 (2 to the power of 8 or 2x2x2x2x2x2x2x2) different values that a byte can represent, which is equivalent to the 256 numbers in the range 0 to 255 in conventional decimal notation. Computer memory is generally measured in multiples of a byte such as Gigabyte and Megabyte. See also bit, Byte, Gigabyte and Megabyte.
Camcorder A contraction of the words ‘camera-recorder’ meaning a video camera and videotape recorder integrated into a single housing. (At one time separate video cameras and videotape recorders were the norm).
Capturing The process of transferring footage from videotape into your computer via a FireWire (IEEE 1394) cable or analogue video capture card.
CD-R Compact Disc Recordable. A compact disc that can have data written to it once only using a CD burner.
CD-ROM Compact Disc-Read Only Memory. A variation of the digital audio CD format that facilitates the storage of general computer files.
CD-RW Compact Disc Re-Writeable. A compact disc that can be erased and re-used by using an appropriate CD-RW burner.
CinePak A video compression codec supported in both QuickTime and Windows Media that was popular in the 1990s for the development of interactive multimedia CD-ROM.
Close-Up Traditionally a video shot in which the head and shoulders of the subject fill the screen.
Codec A contraction of Compressor-Decompressor. A set of software rules which define how to compress and decompress video. Examples include Cinepak, Sorenson Video, Windows Media, Macromedia Flash and the various MPEG flavours including MPEG-1, MPEG-2 and MPEG-4.
Compression Reducing the size of a file. Compression can either be ‘lossless’ or ‘lossy’. Documents such as Word files are compressed ‘losslessly so that no information is lost. Multimedia files such as video can have lossy compression applied, as generally our compressed video file doesn’t need to be identical, bit-for-bit, to the original.
Data Rate The conventional (base 10) number system comprising 10 digits from zero to nine. Contrasts with the base 2 or binary system employed in computing, contain only the two digits 0 and 1.
Deck The video production industry term for a video recorder or VCR (video cassette recorder).
Dial-Up A Dial-up modem is a device that makes a phone call to an Internet Service Provide (ISP) and converts information into audio tones (much like a fax machine). Modem speeds have gradually improved over time to a maximum of 56Kbps; however, this is still a very slow link over which to transfer large multimedia files. The phone line becomes engaged when using a dial-up modem. See also broadband.
Dissolve A type of video transition involving the gradual mixing or blending of one video shot with another over time.
DV Digital Video. A manufacturer standard for consumer and professional recording of video in digital form. The popular consumer Mini-DV format uses 6.25mm (quarter inch) videotape in compact cassettes that store up to an hour of video at a data rate of 25Mbps. DV can be transferred directly from the camcorder to a computer for editing via FireWire.
DVD Digital Versatile Disc (or Digital Video Disc). The same physical size as a compact disc, the DVD packs information much more densely with data capacities from 4.7GB (Gigabytes) to almost 20GB.
DVD-R A recordable (once-only) DVD that can be written with a DVD burner. The cost of DVD burners (or writers) has plummeted and now they are a standard feature in many new computers. The DVD-R is the DVD equivalent of the CD-R.
DVD-RW A rewriteable version of the DVD that can be written to, erased and re-used.
Dub A copy of a video tape.
Establishing Shot Often the opening shot of a video sequence that establishes the context for the viewer. Typically, an establishing shot is wide and is usually followed by increasingly tighter shots such as the close-up.
Ethernet A computer network standard that is common for the connection of computers and printers in the workplace. Speeds available generally range from 11 Megabits per second upward. The ubiquitous blue cables snaking around offices are Ethernet cables.
FireWire A data transfer standard developed by Apple Computer and ratified as international standard IEEE1394. FireWire enables high-speed transfer of digital information (often video information) between computers and hard drives, scanners, digital cameras, camcorders and external drives. FireWire cables are slim and flexible. Sony refers to IEEE1394 as Sony iLink.
Fluid Head A fluid head tripod enables extremely smooth pans and tilts to be performed because the jerky motion of the camera is damped or smoothed by fluid contained within the head of the tripod.
GIF Graphics Interchange Format (tm). An image compression format developed by online service provider CompuServe that is commonly used for graphics on web pages.
Gigabyte One thousand million bytes or 1000 Megabytes of digital information. See also bit, Byte and Megabyte.
Interframe Interframe compression works across frames, taking advantage of information that is common across multiple frames. Interframe codecs contain complete independent keyframes in combination with other frames that are derived from the keyframe. MPEG-1, 2 and 4 are popular interframe codecs. Interframe compression contrasts with intraframe compression.
JPEG Developed by the Joint Photographic Experts Group, a compression format popular for digital still images such as those taken with digital cameras.
Key Frame A fully self-contained, independent frame of video that can exist without reference to any other frames.
Kilobyte 1000 Bytes of digital information (strictly 1024 Bytes). See also bit, Gigabyte and Megabyte.
Locked Off When the head of a video camera tripod is ‘locked off’, the camera remains fixed in a stationary position even if unattended by the camera operator.
Lossless Compression In general when we compress a file we want that file, when subsequently uncompressed, to be identical to the original, with no loss of data. You want your Word document to be identical to the original once it is uncompressed. A software developer distributing software in a zip archive wants to know that you receive an identical copy of the file. With multimedia files such as video it is not critical that every bit be identical to the original source file. See also Lossy Compression.
Lossy Compression In contrast to Lossless Compression, many multimedia files can be compressed using Lossy Compression formats so that even though the file, when it is uncompressed during playback, is not identical at the binary level to the original source file, we still find the results (hopefully) acceptable.
Megabyte One million bytes (strictly 1048576 bytes) or 1024 K. See also bit, Byte, and Gigabyte.
Mini-DV A high-quality digital consumer videotape format using a data rate of 25Mbits/sec popularised in Mini-DV Camcorders. The Mini-DV format, in conjunction with FireWire, has revolutionised video production by dramatically improving quality and convenience.
Modem A contraction of Modulator-Demodulator, a computer peripheral that converts computer data into audio tones that can be transferred over a standard phone line. The maximum speed of a dial-up modem is 56K bits/sec. Broadband modems are capable of much higher data rates.
Motion JPEG A variation of the JPEG still image compression format adapted for use as a video compression codec. Motion JPEG uses intraframe compression.
mp3 A popular compression format for music. mp3 is an abbreviation for MPEG1 Layer 3 Audio and was developed as one of the options available for compressing the audio tracks in an MPEG-1 video file.
MPEG Motion Picture Experts Group. An international body that develops standards for video compression; for example, MPEG-1, MPEG-2 and MPEG-4.
MPEG-1 The first MPEG standard for digital video compression. Released in 1992, it uses data rates of less than 1.8 Mbps and frame sizes of 352x240. Used in the popular Video CD format. MPEG-1 was designed to be played back successfully even on relatively low-powered computers.
MPEG-2 Released in 1995, a higher quality successor to MPEG1 allowing larger frames sizes of up to 720 x 576 pixels (in PAL) and higher data rates of up to 15 Mbps. Has proved highly successful as the video compression standard for DVD and is also used in the transmission of Digital TV.
MPEG-4 Released in 1999 as a video compression standard for low bandwidth devices. MPEG-4 supports data rates as low as 5Kbps and frame sizes down to 144 x 176. It is the first MPEG video compression standard to address the Internet delivery of video and is being adopted for the delivery of video to wireless devices such as 3G mobile phones.
Noise Random information in a communications information such as static heard on a radio when station is tuned in or the ‘snow’ seen on a television when no signal is being broadcast. Noise is very difficult to compress because it contains no redundant information.
NTSC Abbreviation for National Television Systems Committee. The television and video standard used in the USA and Japan. Incompatible with the PAL standard used in Australia and Europe.
PAL Acronym for Phase Alternative Line. The television and video standard used in Australia and Europe. Incompatible with the NTSC standard used in the USA and Japan.
Pan Horizontal movement of a video camera; for example, to follow a running figure. See also tilt.
Pixel A contraction of picture element. The smallest dot on a computer screen.
QuickTime The multimedia software architecture for Macintosh and Windows developed by Apple Computer. QuickTime supports a number of video compression codecs including Sorenson, Cinepak and MPEG-4.
Real Video A video compression codec developed by Real Networks to enable video to be streamed over the Internet
Redundancy Redundant information is unnecessary information. Information may be redundant because it is already available elsewhere; for example, within another part of an image, or from an earlier frame of video. Redundant information can be removed from a file to reduce its size. See also noise.
RGB Monitor Stands for red, green, blue. An RGB monitor displays colour by combining different amounts of red, green and blue light.
Sampling Used to describe the regular, periodic measurement of a signal in order to digitise it. Sampling is usually done very frequently in order to ensure that rapid changes, such as those in a musical performance, are captured with sufficient detail.
Sorenson Video A video codec incorporated into QuickTime from Apple. Sorenson Video is developed by the company Sorenson Vision and was the codec used in 1999 to compress the trailer for Star Wars Episode 1 - The Phantom Menace. When made available from Apple’s website, this was the biggest download event in Internet history with six million users downloading the clip in the first three weeks of its availability
Source File The uncompressed input file to a video compression program.
Streaming Enables the playback of multimedia files such as video without the file ever ‘touching’ the hard drive. Data is transferred straight from the server to the media player (which might be the Windows Media player, QuickTime Player or Real Video player). Quality is limited by the bandwidth of the connection and can be quite variable. A specialised streaming server is required in contrast to a conventional web server, which treats video files in the same way as any other file.
Tilt Vertical movement of a video camera. For example to follow the motion of a seated individual who then stands. See also pan.
Transition A visual effect used to join two video clips together. Common transitions include dissolves and wipes.
Video CD An early format but still popular format for packaging video on Compact Disc. Video CD offers ‘VHS quality’ and uses the MPEG-1 video compression format. Video CD is a popular in Asia.
VHS VHS or ‘Video Home System’ is the most popular consumer analogue videotape format. VHS is a half-inch tape format and was developed by JVC and released in 1996, a year after Sony's Beta format which it eventually displaced.
Windows Media Microsoft's video compression architecture for Windows. Players are also available for Apple Macintosh.
Wipe A type of video transition known as a mechanical transition in which the two video clips being joined ‘slide’ over each other without any of the underlying clip showing through. See also dissolve.