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100Base-T Ethernet
A version of Ethernet that supports a transmission rate of 100 Mbps or megabits per second;
it is often called Fast Ethernet because it is ten times faster than Ethernet.
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Active Content Compression (ACC)
A proprietary video compression algorithm designed specifically for the video security
environment that incorporates intraframe, interframe, and video noise immunity
compression techniques (see ACC White Paper). Less expensive than MPEG-4,
ACC lets you store and send more high quality images at faster update rates
over phone lines and networks than any other compression technique on the
market today.
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Analog video signal
A video signal that takes the form of continuous waves and is displayed via a series of scans.
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Bandwidth
The capacity for transferring data over a network as measured in bits per second (bps), or some
multiple thereof, such as kilobits per second (Kbps), mega or one million bits per second (Mbps),
gigabits per second (Gbps) and terabits per second (Tbps). How much information you can
send across a network and how fast you can send it is determined by the available bandwidth.
A 56K modem, for example, provides a bandwidth of 53.3 Kbps.
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Bitrate (or data rate)
The transmission speed of binary coded data.
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Commercial Off-The-Shelf (COTS)
Describes hardware or software products or solutions that are ready-made and available for sale.
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Common Intermediate Format (CIF)
A commonly used television standard for measuring resolution. One CIF equals 352 x 240
pixels for NTSC and 352 x 288 pixels for PAL. Full resolution is considered 4CIF, which is
704 x 480 pixels (NTSC) and 704 x 576 pixels (PAL). Within the digital video industry,
however, a CIF represents an approximation. The actual number of pixels in a CIF may
vary slightly as long as they provide the same level of overall picture quality. With the
Intellex® digital video management system, for instance, 1CIF equals 320 x 240 pixels,
2CIF equals 640 x 240 pixels, and 4CIF equals 640 x 480 pixels.
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Computer network
Two or more computers that are connected together to share resources such as hardware, data,
and software. Most common types are the local area network (LAN) and the wide area network
(WAN). A LAN can range from a few computers in a small office to several thousand computers
spread throughout dozens of buildings, for example, on a school campus or in an industrial park.
Expand this latter scenario to encompass multiple geographic locations, possibly on different
continents, and you have a WAN.
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Dynamic Host Configuration Protocol (DHCP)
DHCP simplifies the transfer of data by assigning dynamic IP addresses—temporary addresses
that are created anew for each transmission—to devices on the network. DHCP keeps track of
both dynamic and static IP addresses, saving the network administrator the trouble of manually
assigning an IP address each time a new device is added to the network.
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Digital signal
A video signal that is comprised from bits of binary data, otherwise known as 1s and 0s. A video
signal travels from the point of its inception to the place where it is stored and then on to the
place where it is displayed, either as analog or digital. It may be converted from one to the
other, once or several times, while en route. Both digital and analog video signals are
displayed with light and color intensity on fixed dots called pixels.
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Ethernet
The industry standard for local-area networks (LANs), this family of frame-based computer
networking technologies uses copper wires or fiber optics to transmit data sat rates of 10,100,
or 1,000 Mbits per second.
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Gigabit Ethernet
A version of Ethernet that supports a transmission rate of 1 Gbps or one gigabit per second
(the equivalent of 1000 Mbps or megabits per second).
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Images per second (ips)
The speed at which images are transmitted. Motion in video, just as with film or cartoons, is
conveyed by presenting slightly different images in rapid succession. Images are actually
photographs of the same scene shot at split-second intervals, the difference between each
revealing any action or change that has transpired since the one preceding it. The number of
images per second, or speed at which the individual frames are transmitted, determines how
closely the video approximates what you would see if directly viewing the event with your
own eyes. The more images per second, the closer to what the human eye perceives.
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Internet Protocol (IP)
This network layer of the TCP/IP protocol is used in transmission of data over a computer
network such as a LAN, WAN, or the Internet. The IP layer provides features necessary for
the delivery of data including: device addressing, type of service specification, fragmentation
and reassembly of data, and security.
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M-JPEG
A digital video compression format developed from JPEG. JPEG stands for Joint Photographic
Experts Group and is a compression standard for still images. When JPEG is extended to a
sequence of pictures in a video stream, it becomes M-JPEG or Motion-JPEG. Unlike other
compression schemes, each frame is an image unto itself. M-JPEG is an intraframe
technique that works well with single stream or multiplexed stream data, scales
reasonably well, and can be implemented as either constant bit-rate or constant
information codecs.
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MPEG-4
A digital video compression standard for motion pictures developed along the lines of JPEG.
MPEG-4 (MPEG stands for the Motion Picture Experts Group) was originally intended to replace
video conferencing standards (H.320) but its usage has expanded to become, as some say,
“everything to all people”. Yet, it is much more computation and resource intensive than ACC.
Other drawbacks to MPEG-4 can include severe latency, significant hardware acceleration
requirements, and an inability to scale well to multiple sources or multiplexed data streams.
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Power of Ethernet (PoE)
The transmission of both data and electrical power to devices on an Ethernet network via
the same twisted-pair cable.
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Redundancy
Having a secondary computer system, network device, or peripheral that takes over when a
primary unit fails.
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Resolution
The number of pixels in an image. The more pixels, the higher the resolution. The higher the
resolution, the better the picture. (A pixel, by the way, is a colored dot.) —See also CIF.
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Software Development Kit (SDK)
Documentation, utilities and software routines that programmers can use to write applications.
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Switch
A device that splits a network into subsections, allowing users within each subsection to transfer
data to one another without entering—and congesting—the rest of the network. A switched
network is a network that uses a switch to maintain these subsections.
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Transmission Control Protocol/Internet Protocol (TCP/IP)
A set of protocols that has become the standard for communication between networks, including
the Internet. To make transmission more efficient, information is broken down into individual
units or packets of data. The Transmission Control Protocol portion of TCP/IP handles the
tracking of those packets. —See also IP.
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Video analytics
Software algorithms used to analyze video for specific data, behavior, objects, activity, or attitude.
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Video encoder
A device that converts an analog video signal to a digital video signal using one of a variety
of compression schema.
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Video management software
Software applications that allow video to be viewed, recorded, distributed, analyzed,
and shared in real time.
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Wavelet
A popular alternative to JPEG that is attributed with compressing an image more naturally than
methods (like JPEG) that use cosine waves; the net effect is an image that gets softer and
muddier vs. harsher and blockier. Computationally more expensive than JPEG, it is intraframe-
only and performs less effectively than compression methods that use interframe technique
(see ACC White Paper). Real time encoding performance, as with MPEG-4, requires hardware
acceleration. No standards for wavelet compliance currently exist although the JPEG 2000
standard, which has yet to be widely adopted, includes a wavelet implementation section.
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