Optibase MGW 2400 WMT - Manual (Page 148)

Appendix D • Glossary of Terms
remote timesharing system at another site as if the user’s
keyboard and display connected directly to the remote machine.
Threshold – In a digital circuit, a dividing line between circuit-
signal levels representing different digital values.Time Base
Corrector – Equipment that corrects time base errors in video
tape recorders.
Time Base Errors – Analog artifacts being caused in video
tape recorders by non-uniform motion of the tape or the tape
head drum. It is typically visible as horizontal jitter or
instability of the reproduced picture.
Transform – In data compression, a process that converts a
block of data into some alternate form that is more convenient
or efficient.
True Color – Refers to the representation of color by varying
amounts of red, green, and blue. There are 256 shades for each
color available. If you mix all of them together, you obtain 16.7
million possible colors, hence the term True Color.
Truncation – Refers to the technique of reducing the number of
bits per pixel in compressing video (by throwing away some of
the least significant bits from each pixel).
UDP– Refers to the User Data Protocol, a transfer protocol
allowing any station on a network with a standard network card
to transmit or receive information, without the need for a
special interface card.
UDP Block Size – UDP Block size has to be understood as a
buffer that stores information, before it is sent to the network.
This ^buffer^ must hold at least one frame or two fields of
video information, before this information is really sent to the
network. This size is NOT the size of the frame that will be sent
to the network, because - when attached to a network - each
network interface card has its own rules regarding the frame
size. In Ethernet, this size is 1500 bytes. In ATM 53 bytes, and
in Frame Relay 6500 bytes. The network stack running on
MGW, NOT THE SOFTWARE decides the size of the frame
sent to the network. Optibase’s MPEG ComMotion 3.5/3.55 has
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