Operation Manual
Niagara SCX User Guide
ViewCast 33
Tab
Description
from one point to another point.
— In this case, there is just one sender and one receiver.
— Unicast transmission refers to users sending a packet from a single
source to a specified destination.
— Unicast represents the predominant form of transmission on LANs
and within the Internet.
— All LANs (such as Ethernet) and IP networks support the unicast
transfer mode.
— Users should be familiar with the standard unicast applications (such
as http, smtp, ftp and telnet) that employ the TCP transport
protocol.
Multicast communication applies to users sending a piece of information
from one or more points to a set of other points.
— In this case, there may be one or more senders.
— The system distributes information to a set of receivers (there may
be from none to N receivers).
— A video server sending out networked TV channels represents one
example of a multicast application.
— Simultaneous delivery of high quality video to each of a large
number of delivery platforms exhausts the capability of even a high
bandwidth network with a powerful video clip server.
— This poses a major salability issue for applications that required
sustained high bandwidth.
— One way to ease scaling significantly to larger groups of clients is to
employ multicast networking.
— Multicasting, a networking technique, delivers the same packet
simultaneously to a group of clients.
Gamma refers to the response curve of video cameras/CRTs.
When you capture video with a camera, the camera response remains
deliberately nonlinear – it boosts low lumen values and compresses high
lumen values – based on two reasons:
(1) It increases the effective bandwidth in the low lumen range, where
you need it, at the expense of the high lumen range, where you need it
less.
(2) It matches the response characteristics of TV sets and monitors.
The calibration specified in video standards matches the requirements of
cameras and TV sets in broadcast use.
— However, this calibration usually does not match the needs of
computer-based applications or the response curves of computer
monitors.
— Therefore, you often need a correction inverse to the original bias
and you may want to tune for the characteristics of a particular