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The core technology used in a video conference (VC) system
is digital compression of audio and video streams in real
time. The hardware or software that performs compression is
called a codec (coder/decoder). Compression rates of up to
1:500 can be achieved. The resulting digital stream of 1's
and 0's is subdivided into labelled packets, which are then
transmitted through a digital network of some kind (usually
ISDN or IP). The use of audio modems in the transmission
line allow for the use of POTS, or the plain telephony
network in some low-speed applications, such as video
telephony, because they convert the digital pulses to/from
analog waves in the audio spectrum range.
The other
components required for a VC system include:
- video input: video camera or webcam
- video output: computer monitor or television
- audio input: microphones
- audio output: usually loudspeakers associated
with the display device or telephone
- data transfer: analog or digital telephone
network, LAN or Internet
Basic kinds of VC systems and Standards.
Applications of Video Conferencing
Why ISDN Video
Conferencing better than Internet based VC? |
