NETGEAR MP115 User Manual page 30

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Luma: As mentioned in the definition of chroma, the NTSC and PAL video systems use a signal that has
two pieces: the black and white part, and the color part. The black and white part is the luma. It was the
luma component that allowed color TV broadcasts to be received by black and white TVs and still remain
viewable.
Mbps: Abberviation for megabits per second.
Modulator: A modulator is basically a circuit that combines two different signals in such a way that they
can be pulled apart later. What does this have to do with video? Let's take the NTSC system as an example,
although the example applies equally as well to PAL. The NTSC system may use the YIQ or YUV color
space, with the I and Q or U and V signals containing all of the color information for the picture. Two
3.58MHz color subcarriers (90 degrees out of phase) are modulated by the I and Q, or U and V components
and added together to create the chroma part of the NTSC video.
MP3: An MPEG audio file. This is a very popular format for storing digital music.
MPEG: MPEG stands for Moving Picture Experts Group. This is an ISO/IEC (International Standards
Organization) body that is developing various compression algorithms. MPEG differs from JPEG in that
MPEG takes advantage of the redundancy on a frame-to-frame basis of a motion video sequence, whereas
JPEG does not.
MPEG1: MPEG1 was the first MPEG standard defining the compression format for real-time audio and
video. The video resolution is typically 352x240 or 352x288, although higher resolutions are supported.
The maximum bit rate is about 1.5Mbps. MPEG1 is used for the Video CD format.
MPEG2: MPEG2 extends the MPEG1 standard to cover a wider range of applications. Higher video
resolutions are supported to allow for HDTV applications, and both progressive and interlaced video are
supported. MPEG2 is used for the DVD-Video and SVCD formats, and also forms the basis for digital
SDTV and HDTV.
MPEG4: MPEG4 uses an object-based approach, where scenes are modeled as compositions of objects,
both natural and synthetic, with which the user may interact. Visual objects in a scene are described
mathematically and given a position in a two- or three-dimensional space. Similarly, audio objects are
placed in a sound place. Thus, the video or audio object need only be defined once; the viewer can change
his viewing position, and the calculations to update the audio and video are done locally.
Classical "rectangular" video, as from a camera, is one of the visual objects defined in the standard. In
addition, there is the ability to map images onto computer-generated shapes, and a text-to-speech interface.
Network: A collection of PCs, printers, and devices that are connected together in order to share resources.
Network Cable: A cable similar to a telephone line, except large. A telephone cable typically has four
wires
, and a network cable has eight. Also called an RJ45 cable.
NIC: Network Interface Card. Also called a network adapter, a NIC is a device that connects a PC to a
network. Usually this is a card that installs in the PC.
PC: A personal computer.
Playlist: A file containing a list of music files used to play tracks in a particular order. The most common
playlist format is m3u.
PNG: Portable Network Graphics. A popular graphics file format for storing images.
Ripping: A slang term for converting a music CD into compressed music files. Music tracks are ripped
from the CD, compressed, and stored digitally on a hard drive.
RGB: Red-Green-Blue. A top-quality video connection where red, green, and blue components of the
picture are carried through separate wires. This also is referred to as the component video connection.
Router: A device similar to a hub. A router moves data between different network segments, and allow all
users in a network to share a single connection to the Internet.
SCART jack: A SECAM video system. This is another color video format similar to PAL. The major
differences between the two are that in SECAM the chroma is FM modulated and the R-Y and B-Y signals
are transmitted line sequentially. SECAM stands for Sequentiel Couleur Avec Memoire or Sequential Color
with Memory.
Server: A PC or software program that provides services to clients. In this document, the term server refer
to the media software running on a PC.
SNR: Signal-to-noise ratio is the magnitude of the signal divided by the amount of unwanted stuff that is
interfering with the signal (the noise). SNR is usually described in decibels, or "dB" for short; the bigger
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