In general, a path or link through which information passes between two devices. For example, a television channel carries a specific sequence of television programming. In Internet Explorer 4.0, a channel is a collection of Web pages defined by means of a Channel Definition Format (CDF) file.
Channel Definition Format
(CDF) A specification for a format that defines a content channel. Microsoft developed this specification and has presented it to the World Wide Web Consortium (W3C). Applications can use CDF files to offer users subscriptions to Web channels. Such subscription applications automatically update the channel content on a user's computer when this content changes on the channel server. The Internet channel broadcasting components of Broadcast Architecture use CDF files to define subscription content.
chroma
The color portion of the video signal that includes hue and saturation information. Hue refers to a tint or shade of color. Saturation indicates the degree to which the color is diluted by luminance or illumination. See alsoYUV.
class driver
A standard driver provided with the operating system that provides hardware-independent support for a given class of devices. Such a driver communicates with a corresponding hardware-dependent minidriver using a set of device control requests defined by the operating system. These requests are specific to the particular device class. A class driver can also define additional device control requests itself. A class driver provides an interface between a minidriver and the operating system.
closed captioning
Real-time, written annotation of the currently displayed audio content. Closed captioning usually provides subtitle information to hearing-impaired viewers or to speakers of a language other than that on the audio track. On analog television signals, it is transmitted over a specified segment of the vertical blanking interval.
color keying
A display technique in which a selected Video Graphics Array (VGA) color is replaced with video wherever that color appears on the screen. For example, television news programs commonly use color keying to replace a blue backdrop mounted behind a weather announcer with a video picture of a weather map.
(COM) An object-oriented programming model for building software applications made up of modular components. COM allows different software modules, written without information about each other, to work together as a single application. COM enables software components to access software services provided by other components, regardless of whether they involve local function calls, operating system calls, or network communications.
content producer
A person or company creating broadcast content. Content can include television programming, data, Web sites, and software applications.
content provider
A person or company delivering broadcast content. Content can include television programming, data, Web sites, and software applications.
content server application
An application written by a content provider and running on a computer at the broadcast head end that gathers, schedules, and sends data to a computer network for delivery over various types of transport, including computer LANs as well as the vertical blanking interval of an analog television signal.
(CRC) A common technique for detecting errors in data transmission. In CRC error checking, the sending device calculates a number based on the data transmitted. The receiving device repeats the same calculation after transmission. If both devices obtain the same result, it is assumed the transmission was error-free. The procedure is known as a redundancy check because each transmission includes not only data but additional, redundant values for error checking.