Sony PCS-1/1P - Manual (Page 206)

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Glossary
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
videoconference devices on a network.
Administers the zone, access limitation,
audio/video bandwidth, and alias etc.
H.221
Frame structure for a 64 to 1920 Kbps
channel in audiovisual teleservices.
H.261
Video codec for audio/visual services as p ×
64 Kbps. Videoconferencing standard that
defines a video coding algorithm, picture
format and error correcting technology for
communication between different
manufacturers’ video codecs.
H.263
A video coding algorithm based on the
H.261 standard. This format enables
communication via a lower bit rate.
H.263+
Video encoding/decoding format based on
the H.263 standard, added by the Annex I to
T (I, J, K …… T), that allows enhanced
picture quality and error resistance.
Normally, this format is a profile used with
a combination of some of the Annex for
H.263/H.263+.
H.264
A video coding algorithm newly
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.320
A videoconferencing standard for
communication between different
videoconferencing system.
H.323
This enables communications on the non-
QOS (Quality of Service) LAN.
HMLP
See “MLP”.
I-MUX
An abbreviation for Inverse Multiplexer.
This protocol allows you to transmit the data
at 384 Kbps via 6B-channel.
Interlaced SIF
With TV pictures, 60 fields of pictures per
second are interlaced to provide high
resolution and smooth motion pictures.
The conventional videoconferencing system
uses CIF format pictures (352 pixel × 388
line) transmitted in 30 fields per second. In
CIF format, smooth motion pictures like TV
pictures cannot be obtained. In the Interlaced
SIF format, interlaced SIF size pictures (352
pixel × 240 line) can be transmitted at 60
frames per second. This enables display of
pictures with higher vertical resolution of
352 pixel × 480 lines, providing smooth
motion picture. However, a relatively higher
bit rate is required as the amount of
information is twice as much as that of the
CIF format.
ISDN
An abbreviation for Integrated Services
Digital Network. This is a communication
protocol by CCITT on transmission of
integrated voice, video, and data.
Bandwidths include basic (64 Kbps) and
primary rate (1.544 and 2.048 Mbps).
ITU-T
An abbreviation for International
Telecommunication Union,
Telecommunications.
Lip synchronization
A function that synchronizes sound with
motion. Sound processing is much faster
than motion processing, thus sound and
motion sometimes get out of step with each
other.