Course 3: Audio/Video
Common Technologies
The manipulation and distribution of audio and video signals can be as simple as a single connection to a video splitter or switch, or as intricate as is required by the application to provide an ideal A/V environment. Some common convergence technologies include:
Video Converters
A video converter is a device used to convert a source signal into a format that is compatible with the intended display. Because of the variety of signal output types offered by commonplace devices such as VCRs, DVD players or multimedia computers, there are often inconsistencies between the output signal provided, and the capability of the display/monitor. For example, if a VGA video signal is the only option for signal output from a source computer, but the intended display(s) only offer DVI In ports, a straight connection between the computer and monitor(s) is not possible.
Converters are used to:
1) Convert VGA, DVI-I, DVI-D, Component (YPbPr), S-Video, Composite video signals for compatibility with monitors/displays.
2) Convert analog signals to digital, or vice versa.
Video Scalers
Video scalers are used in cases where the resolution and/or aspect ratio of a video signal output does not match the supported resolution/aspect ratio of the display. For example, a high definition television with a native resolution of 720p (1366 x 768) would not be able to display a signal of 1600 x 1200 (UXGA) provided by a computer at optimal viewing levels. As such, a scaler would be used to “downscale” or “downconvert” the UXGA signal to 720p.
Video Extenders
Video Extenders are used to boost or maintain the provided video signal over longer distances than would typically be available, allowing for more practical (and convenient) display placement. Given the advanced capability of displays, especially in the case of high-definition, degraded signal quality can reduce or eliminate the effectiveness of content, if the signal being displayed is not at optimum levels. Video Extenders, therefore, become essential in the delivery of a signal that is unaffected by physical limitations associated with standard video cable technology, even in cases where the signal is broadcast at great distances.
Video Splitters
Video Splitters are used in situations where a single video source needs to be displayed simultaneously on multiple screens. A Matrix Video Splitter or Distribution Amplifier performs a nearly identical function, allowing for multiple video signal sources to be displayed on multiple displays (i.e. two signal selectable sources split and displayed on eight displays).
Video Switches
The function a Video Switch serves is opposite to that of a Video Splitter. Whereas a Video Splitter allows a single video signal to be displayed on multiple screens, a Video Switch allows for multiple signal sources to be used on a single display, enabling users to toggle between sources. This function is especially useful in situations where the number of available signal sources exceeds the provided input ports on the intended display.
AV Cables
AV cables are designed to connect the output signal provided by broadcast devices such as VCRs, DVD players and Multimedia computers, to devices and displays that can output the signal into sound and video. Given the extreme quality of video and sound provided by modern technologies (i.e. DVD, HD DVD/Blu-Ray DVD, HD television), the quality of cable often presents itself as a determining factor in the output quality of the media, especially in the ability to withstand physical limitations and factors such as attenuation and external interference (i.e. Electro-Magnetic Interference) from surrounding devices.
Next – Chapter 3 - Common Applications
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