(^558) PC Hardware: A Beginner’s Guide
Video Terminology
Here are some of the terms and concepts that you should know to work with video on
the PC: Architecture Controls how media is handled by the computer, including how
movies are displayed to the screen and the creation, storage, and playback of
media. It also defines the standard formats used to store media and supports
codecs for audio and/or video. QuickTime, RealSystem, and Video for Windows
are examples of multimedia architectures.
Codec Short for both coder/decoder and compressor/decompressor. Which
meaning is in use depends on the action in use. A coder/decoder is hardware
or software that is used to convert analog sound, speech, or video into digital
code (analog to digital) and vice versa (digital to analog). Hardware codecs are
used in digital telephones and videoconferencing units. Software codecs are used
to record and play audio and video over the Web utilizing the CPU for processing.
A compressor/decompressor is hardware or software that compresses digital
data into smaller files, sometimes encrypted.
Flatten The action used to reduce the frame rate of a video movie to facilitate
its conversion into a digital form.
Format The part of an architecture that sets the actual file description in
which files are stored. For example, the QuickTime architecture contains the
QuickTime MOV file format.
Frame One image in a series that together produce a movie. Multimedia
movies consist of a sequence of still images (frames) and an audio track.
Frame rate The number of frames of a video that is captured per second.
Similar to the capture rate of sound files. This is the primary measure of
reproduction quality. The more frames per second in a movie, the better
the image reproduction will be. A low frame rate produces a jerky image
since pieces of the action motion are missing.
Resolution Refers to the sharpness and clarity of an image displayed on a
graphics monitor. The screen resolution signifies the number of pixels on the
entire screen. For example, a 640 × 480 pixel screen is capable of displaying
640 distinct dots on each of 480 lines, or about 300,000 pixels. Resolution can
also be stated as dots per inch (dpi). A 15-inch VGA monitor (640 × 480) uses
about 50 dots per inch to display an image.
Video capture Converts analog video signals, such as those generated by a video
camera, into a compressed digital format using a special video capture card.Streaming Video
The latest development in multimedia file formats is streaming technology. Streaming
audio and video files are experienced in near real-time. Typically, enough of the file is