NCast Presentation Recorder Reference Manual
the bit-rate to the maximum permitted, which is 10,000 kbps. Reducing the bit-rate, frame-rate and
resolution will allow older PCs operating at lower performance levels to decode the received imagery
without skips and stutters. For the full frame-rate and bit-rate at HD720 resolutions modern PCs in the 2
GHz.+ class are required.
For the lowest bit rate, 128 kbps, a resolution of 640x480 and a frame-rate of 5 frames/second for
graphics or 10 frames/second for video are recommended.
There is no way to define the optimum settings for a given application. It depends on the material being
presented, the expectations for motion smoothness and embedded video performance, the equipment
available to the receiving audience, the maximum network bandwidth available, and other factors. The
only way to determine the optimum settings for a particular installation is to run tests on the material
being presented using the network at hand.
4.7. E
DIT
C
HANNEL
– N
ETWORK
4.7.1. Set Video Stream Destination - AddressAn address entered for Video (the Video or Graphics
media stream) will be either a valid multicast address, or the numeric host IP address of the remote unit if
a point-to-point connection is being established.
A full discussion of multicast addressing is beyond the scope of this document, but briefly summarized,
there are three classes of multicast addresses typically used by multicast applications:
Global Addresses – The range of multicast addresses 224.0.1.0-238.255.255.255 are used for global
communications. These addresses are dynamically allocated and not statically reserved. These
addresses are unsuited for static assignment in the Channel Table.
GLOP Addresses – A document, IETF RFC 3180, describes a mechanism for statically assigned
multicast addresses in the address space 233/8 based on a formula that incorporates the Autonomous
System (AS) number in the middle two octets. The AS number is owned by the ISP providing service to
the account and use of a GLOP address must be coordinated with that ISP.
Administratively Scoped Addresses – The multicast address range of 239.0.0.0 to 239.255.255.255 has
been defined to be a range of administratively scoped multicast addresses in IETF RFC 2365. These
addresses may be statically assigned by the administrator of an organization’s network, and there will be
no conflict with other organization’s use of these addresses because border routers on the edge of an
organization’s network enforce policies to stop multicast traffic flow for addresses within this range.
Further, these same border routers can enforce policies so that subsets of these addresses are
contained within administrative boundaries, such as a local LAN, a building, a campus or a region. These
are safe addresses to use in setting up an organization’s multicast network and ideal entries for use in
the Channel Table. Consult with the Network Administrator for the particular address ranges in use on
the network hosting the Presentation Recorder.
NCast Corporation
Revision 1.0
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