AirLive
POE
‐
200CAMv2
User’s
Manual
114
"flickering" effect. In a surveillance application, this can be critical when viewing detail within a moving
image, such as a person running. A high-quality monitor is required to get the best from progressive
scan. See also
Interlacing
.
Protocol -
A special set of rules governing how two entities will communicate. Protocols are found at many levels of
communication, and there are hardware protocols and software protocols.
Proxy server -
In an organization that uses the Internet, a proxy server acts as an intermediary between a workstation
user and the Internet. This provides security, administrative control, and a caching service. Any proxy
server associated with a gateway server, or part of a gateway server, effectively separates the
organization’s network from the outside network and the local firewall. It is the firewall server that
protects the network against outside intrusion.
A proxy server receives requests for Internet services (such as web page requests) from many users. If
the proxy server is also a cache server, it looks in its local cache of previously downloaded web pages. If
it finds the page, it is returned to the user without forwarding the request to the Internet. If the page is not
in the cache, the proxy server, acting as a client on behalf of the user, uses one of its own IP addresses
to request the page from another server over the Internet. When the requested page is returned, the
proxy server forwards it to the user that originally requested it.
PTZ -
Pan, tilt and zoom.
Resolution -
Image resolution is a measure of how much detail a digital image can hold: the greater the resolution,
the greater the level of detail. Resolution can be specified as the number of pixel-columns (width) by the
number of pixel-rows (height), for example, 320x240.
Alternatively, the total number of pixels (usually in megapixels) in the image can be used. In analog
systems it is also common to use other format designations, such as CIF, QCIF, 4CIF, etc.
RTCP (Real-Time Control Protocol) -
RTCP provides support for real-time conferencing of groups of any size within an intranet. This support
includes source identification and support for gateways like audio and video bridges as well as
multicast-to-unicast translators.
RTCP offers quality-of-service feedback from receivers to the multicast
group as well as support for the synchronization of different media streams.
RTP (Real-Time Transport Protocol) -
RTP is an Internet protocol for the transport of real-time data, for example, audio and video. It can be
used for media-on-demand as well as interactive services such as Internet telephony.
