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Interframe Coding
Intraframe Coding
IP
I-picture; I-frame
IPPV
IRD
IRE
ISDN
ISO
ISOG
EN/LZT 790 0005 R7A
Compression coding involving consecutive frames. When
consecutive frames are compared, temporal redundancy is used to
remove common elements (information) and arrive at difference
information. MPEG-2 uses B and P frames, but since they are
individually incomplete and relate to other adjacent frames, they
cannot be edited independently.
Compression coding involving a single frame. Redundant
information is removed on a per frame basis. All other frames are
ignored. Coding of a macroblock or picture that uses information
only from that macroblock or picture. Exploits spatial redundancy by
using DCT to produce I frames; these are independent frames and
can be edited.
Internet Protocol: The IP part of TCP/IP. IP implements the network
layer (layer 3) of the protocol, which contains a network address and
is used to route a message to a different network or sub-network. IP
accepts packets from the layer 4 transport protocol (TCP or UDP),
adds its own header to it and delivers a datagram to the layer 2 data
link protocol. It may also break the packet into fragments to support
the Maximum Transmission / Transfer Unit (MTU) of the network.
Intracoded Picture/Frame: A picture / frame, which is coded using
purely intracoding with reference to no other field or frame
information. The I frame is used as a reference for other
compression methods.
Impulse Pay Per View: One-time events, purchased at home (on
impulse) using a prearranged SMS credit line.
Integrated Receiver Decoder: The Receiver with an internal MPEG
Decoder, which is connected to the subscriber's TV. The IRD is
responsible for receiving and de-multiplexing all signals. The unit
receives the incoming signal and if CA is active, decodes the signal
when provided with a control word by the viewing card. Domestic
IRDs are also known as Set-Top Units or Set-Top Boxes.
Institute of Radio Engineers: No longer in existence but the name
lives on as a unit of video amplitude measurement. This unit is 1%
of the range between blanking and peak white for a standard
amplitude signal.
Integrated Services Digital Network: The basic ISDN service is BRI
(Basic Rate Interface), which is made up of two 64 kbps B channels
and one 16 kbps D channel (2B+D). If both channels are combined
into one, called bonding, the total data rate becomes 128 kbps and
is four and a half times the bandwidth of a V.34 modem (28.8 kbps).
The ISDN high speed service is PRI (Primary Rate Interface). It
provides 23 B channels and one 64 kbps D channel (23B+D), which
is equivalent to the 24 channels of a T1 line. When several channels
are bonded together, high data rates can be achieved. For example,
it is common to bond six channels for quality videoconferencing at
384 kbps. In Europe, PRI includes 30 B channels and one D
channel, equivalent to an E1 line.
International Standards Organisation.
Inter-union Satellite Operations Group.
Glossary
A-9
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