TANDBERG E5780, Справочное руководство

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Glossary
Reference Guide: evolution 5000 E5780 and E5782 Encoder Page A-7
ST.RE.E10135.4
MMDS
Multichannel Microwave Distribution System: A terrestrial microwave direct-to-home broadcast transmission
system.
Motion Compensation The use of motion vectors to improve the efficiency of the prediction of sample values. The prediction uses motion
vectors to provide offsets into the past and/or future reference frames or fields containing previously decoded
sample values that are used to form the prediction error signal.
Motion Estimation The process of estimating motion vectors in the encoding process.
Motion Vector
A two-dimensional vector used for motion compensation that provides an offset from the co-ordinate position in the
current picture or field to the co-ordinates in a reference frame or field.
MP@ML Main Profile at Main Level: A subset of the MPEG-2 standard, which supports digital video storage (DVD etc.)
and transmissions up to 15 Mbit/s over various mediums.
MP@HL Main Profile at High Level: A subset of the MPEG-2 standard, which supports digital video storage (DVD etc.)
and transmissions up to 80 Mbit/s over various mediums.
MPEG
Moving Pictures Experts Group: The name of the ISO/IEC working group, which sets up the international
standards for digital television source coding.
MPEG-2 Industry standard for video and audio source coding using compression and multiplexing techniques to minimise
video signal bitrate in preparation for broadcasting. Specified in ISO/IEC 13818. The standard is split into layers
and profiles defining bitrates and picture resolutions.
MPEG-4 New industry standard for video and audio source coding using compression and multiplexing techniques to
minimise video signal bitrate in preparation for broadcasting. Specified in ISO/IEC 14496. Part 2 of this standard
defines the original MPEG-4 video compression whereas Part 10 is the new algorithm also known as H.264.
MPEG-4 PT 10 Advanced Video Coding (AVC) standard designed to provide increased coding efficiency over MPEG-2. Specified
in ISO/IEC 14496-10 and as ITU-T Recommendation H.264. The standard is split into profiles which define which
tools can be used and levels which define the allowed bitrates and resolutions
.
MSB Most significant bit.
Msymbol/s (Msym/s) Mega (million) Symbols per second (10
6
Symbols per second).
Multiplex A number of discrete data streams (typically 8 to 12), from encoders, that are compressed together in a single
DVB compliant transport stream for delivery to a Modulator.
MUSICAM Masking pattern adapted Universal Sub-band Integrated Coding And Multiplexing: An audio bitrate reduction
system relying on sub-band coding and psychoacoustic masking.
Mux Multiplexer: Transmission Multiplexer: receives EMMs from the ACC, ECMs from the BCC, video/audio data from
the encoders, and the SI stream from the SIC. It then multiplexes them all into a single DVB-compliant transport
stream, and delivers the signal to the uplink after modulation.
The Multiplexer also contains the cipher card, which scrambles the services according to the control words
supplied by the BCC.
Network
In the context of broadcasting: a collection of MPEG-2 transport stream multiplexes transmitted on a single
delivery system, for example, all digital channels on a specific cable system.
NICAM Near Instantaneously Companded Audio Multiplex: Official name is NICAM 728. Used for digital stereo
sound broadcasting in the UK employing compression techniques to deliver very near CD quality audio.
728 refers to the bitrate in kbit/s.
NIT Network Information Table: Part of the service information data. The NIT provides information about the physical
organisation of each transport stream multiplex, and the characteristics of the network itself (such as the actual
frequencies and modulation being used).
nm Nanometre: a unit of length equal to one thousand millionth (10
-9
) of a metre.
NTSC National Television Systems Committee: The group, which developed analogue standards used in television
broadcast systems in the United States. Also adopted in other countries (e.g. Mexico, Canada, Japan). This
system uses 525 picture lines and a 59.97 Hz field frequency.
NVOD Near Video On-Demand: Method of offering multiple showings of movies or events. The showings are timed to
start at set intervals, determined by the broadcaster. Each showing of a movie or event can be sold to subscribers
separately.
NVRAM Non-volatile Random Access Memory: Memory devices (permitting random read / write access) that do not lose
their information when power is removed. Stores the default configuration parameters set by the user.
OFDM Orthogonal FDM: A modulation technique used for digital TV transmission in Europe, Japan and Australia; more
spectrally efficient than FDM. In OFDM, data is distributed over a large number of carriers spaced apart at precise
frequencies. The carriers are arranged with overlapping sidebands in such a way that the signals can be received
without adjacent channel interference.
OID Object Identifier is the part of the SNMP message that defines which module should receive the command.