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Glossary

B

bandwidth
The upper limit on the amount of data, typically expressed as Kilobits per second (Kbps), that can pass through a network connection per second.

bit
The smallest unit of measure of data in a computer. A bit has a binary value, either "0" or "1."

bit rate
The number of bits transmitted per second. A 28.8 Kbps modem, for example, can transmit or receive around 29,000 bits per second.

buffering
The process of receiving and storing presentation data before playing it back. RealMedia presentations have an initial buffering time called "preroll". Once the presentation starts, buffering should be minimal or the presentation may pause.

byte
A common unit of data measurement. One byte is composed of eight (8) bits.

C

client
General term for a software application that receives data from a server. A Web browser is a client of a Web server. RealPlayer is a client of RealServer.

clip
A single file in a presentation. The term typically refers to media files with internal timelines, such as audio or video.

Codec
Compressor/decompressor. Codecs convert between an uncompressed (raw) format and a compressed format such as RealAudio. They reduce the amount of bandwidth a streaming file consumes.

D

download
To send a file over a network so that the entire file must arrive before the file contents display. Contrast to "stream".

E

encoding
The method of converting and compressing a file into a smaller, streaming format. For example, you use an encoding tool and a Codec to encode sound files as RealAudio.

H

HTTP
The protocol used by Web servers to communicate with Web browsers. RealServer can use HTTP, but it streams files to RealPlayer with RTSP.

I

ISP
Internet Service Provider. A company that provides access to the Internet. Many ISPs have RealServer available to stream media.

K

Kilobit
A common unit of data measurement equal to 1024 bits. A Kilobit is usually referred to in the context of bit rate per unit of time, such as Kilobits per second (Kbps).

Kilobyte
A common unit of data measurement equal to 1024 bytes.

P

PNA
A proprietary protocol RealServer 6.0 supports for backwards compatibility with RealSystem versions 3.0 through 5.0.

preroll
Buffering that occurs at the start of the presentation. A presentation should have a preroll under 10 seconds.

presentation
A group of clips coordinated through SMIL and streamed from RealServer to RealPlayer.

R

RDP
The proprietary data package protocol RealServer 6.0 uses (along with RTSP) when communicating with RealPlayer 6.0. Contrast to "RTP".

RealPlayer
RealNetworks client designed to play multimedia presentations streamed by RealServer.

RealServer
RealNetworks software used to stream multimedia presentations to RealPlayer.

real-time

RTP
The open, standards-based data package protocol RealServer 6.0 uses (along with RTSP) to communicate with RTP-based clients. Contrast to "RDP".

RTSP
The open, standards-based control protocol RealServer 6.0 uses to stream files to RealPlayer 6.0 or any RTP-based client. Contrast to "HTTP".

S

server
1. A software application such as a Web server or RealServer that sends files over a network.
2. The computer that runs server software.

SMIL
Synchronized Multimedia Integration Language. A mark-up language similar to HTML that describes how and when each clip in a presentation is played.

stream
v. To send a media file over a network so that it begins playing back before all file data has arrived.
n. A flow of a single type of data, measured in Kilobits per second (Kbps). A presentation's soundtrack is one stream, for example.

U

URL
Universal Resource Locator. A location description that lets a Web browser or RealPlayer receive a file stored on a Web server or RealServer.


Copyright © 1998 RealNetworks
For technical support on RealNetworks products, visit http://service.real.com/.
Comments on this document? Contact techpubs@real.com.
This file last updated on 05/20/98 at 16:52:08.
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