NCast PR720 - Manual (Page 6)

NCast Presentation Recorder Reference Manual
1. Introduction
1.1. P
URPOSE
The NCast Presentation Recorder Reference Manual is intended for the Audio/Video or Network engineer
who will be tasked with the job of installing and setting up a Presentation Recorder or a system of multiple
Presentation Recorders. This guide is designed to cover topics in depth and to assist in optimizing the
performance of a Presentation Recorder.
1.2. D
OCUMENT
O
VERVIEW
This document is divided into two major sections: the theory of operation and a discussion of parameter
settings.
1.3. T
ERMS AND
D
EFINITIONS
A complete discussion of MPEG compression, Internet streaming, webcasting protocols and related topics is
beyond the scope of this document. Other sources cover this material in great detail. The following are brief
definitions of some of the terms used throughout this manual.
AAC – Advanced Audio Coding, a wideband audio encoding and compression algorithm.
Auto-detect – A capability to automatically sense if an input signal (graphics or video) is
present and to lock onto that signal without further manual intervention.
CIF - Describes an image or display surface with a resolution of 352x288 pixels.
DVI – Digital Visual Interface, a digital interface standard which provides for connection to
LCD panels and displays.
H.264 – A compression format that delivers very high quality video at low bit rates. MPEG-4
Part 10 utilizes the H.264 codec for transmission.
IETF – Internet Engineering Task Force, the standards body for Internet protocols.
ISO – International Standards Organization
Latency – The end-to-end time delay between a change in the source image and the
corresponding change in the remotely displayed image.
Line-Level – Sound level signals typically in the range of –10 dBu to +30 dBu.
Lip-sync – The synchronization of independent audio and video streams at a receiving
decoder so that the presentation is in the same time relationship as the source.
Mic-Level – Sound level signals typically in the range of –70 dBu to –30 dBu.
MPEG Compression – MPEG is an acronym for Motion Picture Experts Group, an industry-
wide committee which has defined a series of standards for the compression of audio and
video source material.
MTU – The maximum transmission unit is the maximum number of bytes permitted in a
transmitted packet.
Multicast – A family of computer transmission protocols where multiple receivers access a
single transmitted packet stream.
NCCP – NCast Conference Control Protocol provides coordination, control and identification
of participants in a multi-way collaborative conference session.
N-Way – An NCast proprietary service for multicast bridging and webcasting.
NCast Corporation Revision 1.1
Page 6