User's Manual Part 2

Tech-X Flex
®
(NG2) Tech-X Flex User Guide - Firmware v06.50
6-41
Intro
Overview
Wi-Fi
Ethernet
System
IP/Video
MoCA
RF
Specs
Figure 6-20 Compressed video stream frames
Audio compression
Audio compression has some similarity to video compression, in that techniques may be used to
eliminate redundant data. Furthermore, audio exhibits the concept of “masking,” where one frequency
may mask another and the human ear is unable to perceive it. Because it is unnecessary to transmit any
data for sounds that will never be heard, the removal of this data from the original audio stream provides
further possibilities for data reduction.
Additional details of encoding, decoding, and compression algorithms are complex and beyond the
scope of this document.
About MPEG transport
The MPEG standards refer broadly to a set of protocols for transporting compressed audio/video
programs over a communications network, such that a decoder can properly reconstruct the audio/video
programs at the destination. It is overseen by the Moving Picture Experts Group
(http://www.chiariglione.org/mpeg/).
A fundamental concept of MPEG transport is the “program,” the higher-level entity that end users receive
when they select a “channel.” Fully-decoded, an MPEG program is the entire dataset required to present
a single multimedia experience to the user, such as the complete and synchronized audio/video streams
required to watch a single IPTV channel.
The preparation of the audio/video programs has two fundamental stages:
I frames P frames B frames
Preliminary issue - Limited distribution only!