Specifications
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A Digital Video Primer
Codec: Compressor/decompressor or encoder/decoder; hardware or soware that handles the
compression of audio and video to make it easier to work with and store, as well as decompres-
sion for playback.
Color sampling: A method of compression that reduces the amount of color information (chro-
minance) while maintaining the amount of intensity information (luminance) in images.
Component video: A video signal with three separate signals: Y for luminance, Cr for chroma/
red, and Cb for chroma/blue. Component signals oer the maximum luminance and chro-
minance bandwidth. Some component video, like Betacam and Betacam-SP, is analog; other
component video, like D1, is digital.
Composite video: An analog video signal that includes chrominance and luminance informa-
tion. NTSC, PAL, and SECAM are the international standard formats for composite video.
Compositing: e process of combining two or more images to yield a resulting, or composite image.
Compression: Reducing the amount of data in digital video or audio.
Compression ratio: A comparison of the amount of data before and aer compression is applied.
Crawling title: Text or graphics that move horizontally across the screen.
Cut: e simplest type of transition, in which the last frame of one clip is simply followed by the
rst frame of the next.
DAM: Digital asset management; see Media asset management.
Data rate: Amount of data transferred over a period of time, such as 10MB per second. In digital
media, data rate is the amount of data required each second to render audio or video in real time.
Digital: A system that uses numbers, such as a computer system. Digital media are sounds and
images represented by binary numbers.
Digital asset management (DAM): See Media asset management (MAM).
Digitize: To convert an analog audio or video signal into a digital bitstream.
Dissolve: A fade from one clip to another.
DTV: Digital television.
Duration: e length of time a video or audio clip or sequence of clips plays; the dierence in
time between an In point and Out point.
DV: Generally refers to digital video, but current usage suggests a variety of nuances. DV can
refer to the type of compression used by DV systems or a format that incorporates DV com-
pression. DV camcorders employ a DV format; more specically, a standard consumer DV
camcorder uses mini-DV tape, compresses the video using the DV25 standard, and has a port
for connecting to a desktop computer. e DV designation is also used for a special type of tape
cartridge used in DV camcorders and DV tape decks.
DVD: A digital storage medium that looks like a CD but has higher storage capacity. A DVD can
store a feature length lm compressed with MPEG-2.
DVI: Digital Video Interface, a connection interface for high-end digital video equipment.
DV25: e most common form of DV compression, using a xed data rate of 25 megabits per
second (Mbps).
EDL: Edit decision list, a master list of all edit In and Out points, plus any transitions, titles, and
eects used in a lm or video production. An EDL can be sent to an edit controller, which is a
device that interprets the list of edits and automatically controls the decks or other gear in the
system to create a nal edit from original sources.
Effect: A process used to modify the quality of audio or video. In digital media, eects are
typically programs or plug-ins that manipulate data to change the appearance of video or the
character of the audio.