OPTICODEC-PC GLOSSARY
8-15
SHOUTcast™
signal-to-noise ratio
SIP (Session Initiation Protocol)
An Internet protocol that provides simple appli-
cation layer signaling for setting up, maintaining, and terminating multimedia ses-
sions such as voice calls, videoconferences, and even instant messaging sessions. SIP
performs many of the functions of the ITU H.323 multimedia conferencing standard,
which was largely specified by the telecoms. SIP provides a more-scalable, higher-
performance, and more-efficient calling model. Because it is designed on the Inter-
net model, it is inherently distributed and supports the development of telephony
applications on Internet systems.
SMB (Server Message Block)
Renamed CIFS
SMIL
SMTP (Simple Mail Transport Protocol)
A protocol for sending email.
sprite
An animated image that is managed by QuickTime. A sprite is defined once
and is then animated by commands that change its position or appearance.
SNMP
SNR (signal-to-noise ratio)
S/PDIF
SPI (Stateful Packet Inspection)
SSL (Secure Sockets Layer)
An Internet protocol that allows you to send en-
crypted, authenticated information across the Internet.
static IP address
An IP address that is assigned to a computer or device once and is
never changed.
streaming
Delivery of audio or video data over a network in real-time, as a stream
of packets instead of a single file download.
TCP (Transmission Control Protocol)
A method used along with the Internet Pro-
tocol (IP) to send data in the form of message units between computers over the
Internet. IP takes care of handling the actual delivery of the data, and TCP takes care
of keeping track of the individual units of data (called packets) into which a mes-
sage is divided for efficient routing through the Internet.
TDMA
temporal compression
Image compression that is performed between frames in a
sequence. This compression technique takes advantage of redundancy between ad-
jacent frames in a sequence to reduce the amount of data that is required to accu-
rately represent each frame in the sequence. Sequences that have been temporally
compressed typically contain key frames at regular intervals.
TFTP
track
A QuickTime data structure that represents a single data stream in a Quick-
Time movie. A movie may contain one or more tracks. Each track is independent of
other tracks in the movie and represents its own data stream.
transparent rating
When a codec’s output cannot be distinguished from its input
in a statistically significant manner by a panel of expert listeners or viewers in bias-
