Video Capture Glossary
ANTI-ALIASING A method of smoothing out jagged edges on
screen and in bitmap image files.
EDITING Linear editing process whereby shots recorded by your
camcorder are copied individually onto a tape in a VCR. Assemble editing allows
you to miss out, truncate or rearrange shots.
MIXER Device or software program for mixing sounds from several
sources, such as a microphone, CD and sound from the camcorder tape.
stand-alone mixers, each sound source plugs into a different input and the
combined output is put out onto a new tape or into a computer. individual level
controls for each input enable you to balance the various sound
Audio Video Interleaved. one of two main file formats for digital video the
other is Quicklime.
Basic Input Output System: the chip or set of chips in a computer that controls
how the computer communicates with hardware components, such as the disk drives
and the keyboard.
The smallest element in digital systems the often mentioned noughts and ones of
computing. Also used as a measure of color depth, The more
bits per pixel,
the greater the number of colors. There are eight bits in a byte.
The file extension given to Windows graphics files saved in an enhanced Device
Independent Bitmap (DIB) format.
BITMAP An image format made up of pixels arranged in
The process of starting up a computer.
CACHE Memory used to improve the speed of different
computer components. including disk drives, video cards and the central
processing unit (CPU).
CARD/DIGITIZER Board that connects to the input of a computer and
enables a video signal from a camcorder to be converted to a digital signal in a
form that can be read and processed by a computer It then performs the opposite
process, playing back to a recorder. Essential for non-linear
SIZE The smallest amount of disk space that a file can occupy, With
hard disks, the larger the size of the disk, the larger the cluster. On many
computers, including those using DOS, Windows 3.x,Windows 95 (Original Version)
and Mac OS,this results in much wasted hard disk space because individual small
files each occupy a whole cluster much larger than the file itself.
CHROMINANCE The color component of the video
signal, denoted by the letter 'C' In high-band camcorders (Hi8, S-VHS and S VHS
C),the video signal is split into luminance (brightness) and chrominance
(color). Processing the two signals separately helps improve the picture
quality and avoid effects such as moire patterning - the tartan-like
interference seen on fine patterns in a scene.
The part of a computer's memory that stores information about the components
fitted to the computer, including the number and type of hard and floppy disk
drives. If the battery backing up this information goes flat it will be lost and
the computer will not be able to boot-up.
Cyan/Magenta/Yellow/blacK. Most desktop color
printers mix links of these four colors to produce a full spectrum of colors.
CODEC Compressor/Decompressor, compresses (packs) and decompresses
(unpacks) image data. Compression codec's can use software or hardware
carry out their tasks.
COMPONENT Video systems that process the chrominance
and luminance signals separately between recording and viewing. Used in
high-band analogue and digital systems, it results in sharper pictures and
VIDEO Combination of chrominance and luminance signals, which are
processed together in low-band (8mm, VHS-C, VHS) camcorders. Using this system
reduces both the cost of equipment and the quality of the signal.
COMPRESSION Reducing the size of a file on disk or in
memory. Compression can be lossless (ie compressed without any loss of
information) or lossy, in which some data is discarded, on the assumption that
the loss will not be noticeable when the data is decompressed.
Central Processing Unit The heart and lungs of a computer. The Pentium processor
and PowerPC are examples of modern CPUs.
RATE Amount of data that a storage device, such as a hard disk or
CD-ROM saves/plays back per second, or the amount of data per second in a video
DEFRAGMENT The process of re-arranging the files on
a disk so that each file larger than one cluster in size is stored in adjacent
clusters, rather than split up and stored at different places on the disk. If a
hard disk contains many fragmented files (caused by repeatedly writing and
erasing information to/from a disk) programs will run slowly, because it
longer to load such files than it would if they weren't scattered
around the disk.
VIDEO (formerly DVC) Consumer video recording format that is set to
supersede analogue formats (such as 8mm and S-VHS). The main advantages of DV
over analogue are the higher quality of the picture and the fact that it isn't
noticeably degraded by copying. Cassettes are smaller than 8mm or VHS-C. In the
broadcast market, various other digital formats are available, such as DVCPro
(Panasonic), DVCam (Sony)
and Digital-S (JVC).
Dots per inch. The resolution of printers and scanners are both
measured in dpi - usually quoted both horizontally and vertically. An apparent
doubling of the dpi - say from 360x360 to 720x720, results in a quadrupling of
the total number of dots. DOS Disk Operating System.
DRIVER Software used to make computer peripherals
such as video cards, printers, soundcards and scanners work with a particular
type of computer.
EXTENSION The three-letter 'tail' of an MS DOS or
Windows filename (preceded by a full stop).It's used by programs to distinguish
one type of file from another. As an example .TXT is used for plain text files.
GB Gigabyte. Hard disk drive manufacturers inevitably overstate the size of the
products they sell because, while the rest of the world believes a gigabyte
consists of 1,024 megabytes, they rather conveniently, think it is 1,000
file extension most commonly used by graphics files intended for transmission
over the Internet. Modern Internet browser programs allow interlacing GIF files,
so the image can be partly seen before it has been completely downloaded. If the
image is not wanted, the download can be stopped saving time and
DISK A disk drive, usually fitted out of sight inside a PC, on which
the programs used by a computer and the data they generate are stored. Hard
disks are much faster in use than floppy disks and also hold much more
High-band analogue camcorder small tape format developed by Sony.
HIGH-BAND The better quality analogue video formats
Hi8, S-VHS, S-VHS-C and High-Band U-matic.Chrominance (color) and luminance
(brightness) are processed separately in such systems for better resolution than
RESOLUTION The number of alternate black and white lines per inch a
video format is capable of resolving. Low-band formats should be able to resolve
more than 250; high-band more than 400.
Interrupt Request Line. The ID number used by a piece of hardware when
identifying itself to the central processor.
INTERRUPT In effect an electronic flag waved by a bit
of hardware to catch the attention of a computer's central processor.
graphics file format developed by the Joint Photographic Experts Group. The file
extensions JPG and JIF are both used to distinguish JPEG files. Although JPEG
files use a lossy compression, which greatly reduces file sizes, image quality
is surprisingly good.
(Control L) Edit control socket found on many 8mm and Hi8 camcorders. With the
appropriate lead, information about the camcorder's tape counter position can be
transmitted to a VCR (for synchro-edit) or edit controller. Tape transport
commands (play record etc) can also be sent along the lead so that the camcorder
can be controlled remotely.
EDITING Process of copying shots from one videotape to another in
Standard analogue camcorder formats VHS, VHS-C and 8mm.
Linear or Longitudinal Time code An alternative time code method to RCTC and VITC
used by some professional computer editing packages. Information is recorded on
the tape's linear edge track, so mono audio is lost.
Megabyte. 1024 kilobytes, though hard disk makers believe it is 1000
M-JPEG The Motion Joint Photographic Experts Group
video compression standard. Based on the JPEG standard developed originally for
individual still images. The amount of information contained in even a single
second of video is huge. To make digital video recording a practical
proposition, therefore, capture cards compress the signal as it's being
digitized. M-JPEG is the most commonly used format in home and semi-pro video
systems. Captures are written, usually together with audio brought in separately
from a soundcard, to one of two types of computer file AVI (audio/video
interleaved) or Quicklime. The ultimate file size is determined by the number of
frames sampled each second, the amount of compression applied and the length of
footage being transferred to disk. The other major compression system currently
in use is MPEG.
The Motion Picture Experts Group standard for video compression. It achieves
much of its file size reduction by recording only certain critical frames, plus
the changes that take place between them. MPEG works best in professional
systems where the editor can override automatic settings to make decisions, such
as which additional frames should be included in their totality.
NON-LINEAR EDITING Editing video on computer hard disk.
Disks are non-linear format - they store the data in a random order and allow
virtual instant access to any part of it Non-linear editing may be carried out
with a home computer, such as a Mac or PC. The video from the camcorder passes
through a digitiser and is stored on the computer's hard disk (a lot of hard
disk space is required gigabytes, rather than megabytes). Appropriate software
allows you to review shots, create an edit decision list, add titles and special
effects, then preview the edited movie, before copying it to
NTSC National Television
Standards Committee. The TV system used in Japan and much of the Americas
including the USA.
OPERATING SYSTEM The
software used to control a computer and run programs. DOS, Windows 98 and Mac OS
are the best known operating systems.
PAL Phase Alternating Line. The TV standard used in
Western Europe (except France) and Australia, and much of East Africa, India and
PARTITION A hard disk can be
partitioned to create two or more logical hard disk drives. The main reason to
do this is to be able to have different operating systems running on a single
computer, and to prevent wasted hard disk space by reducing the cluster
PHOTO CD Negatives and slides of
35mm film stock can be turned into PCD files, and transferred to PhotoCD, by
photo finishers. Each file is usually greater than 4Mb in size and contains five
versions of the image, covering five resolutions - 192 x 128 pixels;256x384,
512x768, 1024x1536 and 2048x3072.
Picture Element A single dot which is the smallest unit displayed on a computer
monitor or in a digital image, and which is the smallest imaging element on a
QUICKTIME One of two
main file formats for digital video - the other is AVI.
RAM Random Access Memory. The
memory used to run programs and hold data while programs are running. Anything
held in RAM is lost when the computer is turned off.
RE-BOOT Re-starting a computer.
SCART 21-pin plug for connecting audio and video
signals between VCRs and televisions, or between two VCRs. Also known as
Euroconnector and Peritel. Some Scart plugs have pins disabled.
Sequentiel Couleur avec Memoire TV standard used in France and parts of Eastern
SOFTWARE Programs used on a computer S-VHS/S-VHS-C
Super VHS is a high-band version of standard VHS and VHS C (C stands for
SYNCHRO-EDIT Simple editing system that relies on a
control lead between camcorder and VCR so that both machines can be controlled
by one set of buttons. Pre-roll delay is also built into the synchro-edit system
to compensate for backspacing.
TIMECODE A system that allocates an individual label to
each frame of video, based on hours, minutes, seconds and frames, plus a tape
identifier. Used to ensure accuracy at the editing stage.
Video Home System. Videotape format designed to be used in VCRs and
VHS-C VHS (Compact) videotape housed in smaller
cassettes, designed to be used in camcorders.
Vertical IntervalTimecode. Video frames are individually labeled for
frame-accurate editing. VITC cannot be added to a
videotape without disturbing other signals, so it has to be added either during
recording or when copying video tapes.
WILDTRACK Ambient sound recorded on location or
afterwards and used at the editing stage to add atmosphere. Without it scenes
can sound hollow or artificial. Often referred to as 'atmos' it can also help to
smooth out the transition between cuts.
Electronic transition where one shot gradually obscures the previous shot Wipes
can be anything from simple straight lines passing across the screen to complex
Component video using separate luminance (Y) and chrominance (C)
signals - S-VHS quality.
Component video made from separate luminance (Y) and two color difference
(U&V) signals Betacam-SP level quality.