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Glossary
Glossary
ARC
An abbreviation for Adaptive Rate Control.
Technology which automatically lowers a
video streaming bitrate against network
congestion.
ARQ
An abbreviation for Automatic Repeat
reQuest. Error control method in which the
receiver requests a retransmission from the
transmitter when a packet loss occurs.
Auto Bandwidth Detection
Detects the network bandwidth and others
before communication. By using this value
for the QoS function, optimum QoS control
is available from the beginning of the
communication.
Codec
An abbreviation for COder-DECoder. An
integrated device of a coder that converts an
analog audio/video signal to a digital data
stream and compresses it, and a decoder for
expanding to restore the original analog
signal.
DHCP
An abbreviation for Dynamic Host
Configuration Protocol. Manages IP
addresses in the network.
DNS
An abbreviation for Domain Name System.
Defines the domain name system.
Echo Canceler
Device to eliminate echo that occurs when
transmitting audio.
FEC
An abbreviation for Forward Error
Correction. Error control method in which
the receiver can correct errors without
requesting a retransmission from the
transmitter.
Frame rate
The number of frames which can be
encoded/decoded in one second.
G.711
Audio encoding/decoding format
recommended by the ITU-T. A phone
bandwidth audio signal is converted to a
digital signal with a data rate of 64 Kbps. It
can be transmitted with a data rate of 56
Kbps.
G.722
Audio encoding/decoding format
recommended by the ITU-T. A 7-kHz
bandwidth audio signal is converted to a
digital signal with a data rate of 48 Kbps, 56
Kbps or 64 Kbps.
G.728
Audio encoding/decoding format
recommended by the ITU-T. A phone
bandwidth audio signal is converted to a
digital signal with a data rate of 16 Kbps.
Gatekeeper
Controls the access of H.323 video
communication devices on a network.
Administers the zone, access limitation,
audio/video bandwidth, and alias etc.
H.264
A video coding algorithm standardized by
the ITU-T in May 2003. This format realizes
high-quality picture via a lower bit rate. It
provides an equal picture quality via half as
low bit rate as the H.263 format. The H.264
format is also called as MPEG4 Advanced
Video Coding (AVC).
H.323
This enables communications on the non-
QOS (Quality of Service) LAN.
HD
An abbreviation for High Definition. High
Definition television provides a high-
resolution and high-quality picture. There
are 1080i and 720p HD formats.
HD-SDI
High Definition Serial Digital Interface.
This is the standard that defines business-use
serial digital video format.
