A
-
Advertising Application
-
A RealServer option that inserts ads into SMIL-based presentations. SMIL files use
<RealAdInsert/>
tags to indicate ad placement.
-
artifact
-
A visual imperfection in an encoded video clip. Too many artifacts can make the video look blocky.
B
-
bandwidth
-
The upper limit on the amount of data, typically expressed as kilobits per second (Kbps), that can pass through a network connection.
-
banner ad
-
An ad that appears alongside a requested clip or presentation. A banner ad can also rotate, making new ad images appear at regular intervals.
-
bit
-
The smallest unit of measure of data in a computer. A bit has a binary value, either
0
or 1
.
-
bit rate
-
A measure of bandwidth, expressed as the number of bits transmitted per second. A 28.8 Kbps modem, for example, can transmit or receive around 29,000 bits per second.
-
broadcast
-
To deliver a presentation, whether live or prerecorded, in which all viewers join the presentation in progress. Contrast to on-demand.
-
buffering
-
The receiving and storing of data before it is played back. A clip's initial buffering is called preroll. After this preroll, excessive buffering may stall the presentation.
-
byte
-
A common measurement of data. One byte consists of 8 bits.
C
-
cable modems
-
Devices that allow rapid transmission and reception of data over television cable. They are digital devices, unlike dial-up modems, which transmit analog data.
-
CBR
-
Constant Bit Rate. A type of RealVideo encoding in which all parts of the video play back at the same bit rate. Contrast to VBR.
-
CHTTP
-
A version of HTTP supported by RealPlayer. Files designated with
chttp://
are downloaded through HTTP and stored in RealPlayer's cache.
-
client
-
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 media file within a presentation. Clips typically have an internal timeline, as with RealAudio and RealVideo.
-
codec
-
Coder/decoder. Codecs convert data between uncompressed and compressed formats, reducing the bandwidth a clip consumes.
D
-
download
-
To send a file over a network with a nonstreaming protocol such as HTTP. Contrast to stream.
-
DSL
-
Digital Subscriber Line. A technology for transmitting digital data over a regular telephone line at speeds much faster than dial-up modems.
-
duress stream
-
A low-bandwidth SureStream audio or video stream that RealServer uses if a connection's available bandwidth drops greatly.
E
-
encoding
-
Converting a file into a compressed, streaming format. For example, you can encode WAV files as RealAudio clips.
F
-
Flash
-
A software application and an animation format created by Macromedia. RealPlayer can play Flash animations and stream them in parallel with other clips, such as RealAudio clips.
-
Flash Player file
-
A compressed Flash file format (file extension
.swf
) suitable for streaming. To stream Flash, you export the Flash Player file and tune it so that it plays well in RealPlayer.
-
fps
-
Frames Per Second. The number of video frames that displays each second in a streaming video clip.
-
frequency response
-
A measure of audio clip quality. The higher a clip's frequency response, the more frequencies it can faithfully reproduce.
H
-
HTTP
-
Hypertext Transport Protocol. The protocol used by Web servers to communicate with Web browsers. In contrast, RealServer streams clips to RealPlayer with RTSP. See also CHTTP.
I
-
interstitial ad
-
An advertisement that interrupts playback of a requested clip. It is like a commercial break on television.
-
ISDN
-
Integrated Services Digital Network. Technology that makes digital data connections at 64 or 112 Kbps possible over telephone lines.
-
ISP
-
Internet Service Provider. A company that provides access to the Internet. Many ISPs have RealServer available to stream media clips.
K
-
kilobit (Kb)
-
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 (KB)
-
A common unit of data measurement equal to 1024 bytes or 8 kilobits.
L
-
LAN
-
Local Area Network. A computer network confined to a local area, such as a single building. LANs vary in speed, with bandwidth shared among all networked devices.
-
lossy
-
A compression scheme that lowers clip size by discarding nonessential data from the source file. Both RealAudio and RealVideo are lossy.
M
-
mouseover
-
The action of moving a computer screen pointer over an interactive area. An animated button may change appearance on a mouseover, for example.
0
-
on-demand
-
A type of streaming in which a clip plays from start to finish when a user clicks a link. Most clips are streamed this way. Contrast to broadcast.
P
-
PNA
-
A proprietary protocol RealServer uses for backward compatibility with RealSystem 3 through 5. URLs using PNA start with
pnm://
.
-
port
-
A connection to a server, designated by a number such as 8080. RealServer uses different ports for the RTSP, HTTP, and PNA protocols.
-
preroll
-
Buffering that occurs before a clip plays back. Preroll should be no more than 15 seconds.
-
presentation
-
A group of clips coordinated through SMIL and streamed from RealServer to RealPlayer.
R
-
RDT
-
The proprietary data package protocol RealServer uses (along with RTSP) when communicating with RealPlayer. Contrast to RTP.
-
RealAudio
-
A RealSystem clip type for streaming audio over a network. RealAudio clips use the
.rm
extension.
-
RealPix
-
A RealSystem clip type (file extension
.rp
) for streaming still images over a network. RealPix uses a markup language for creating special effects such as fades and zooms.
-
RealPlayer
-
RealNetworks client software designed to play multimedia presentations streamed by RealServer or a Web server.
-
RealProducer
-
The primary RealNetworks tool for encoding RealAudio and RealVideo clips.
-
RealServer
-
RealNetworks server software used to stream multimedia presentations to RealPlayer.
-
RealServer administrator
-
The person in charge of setting up and running RealServer.
-
RealSlideshow
-
A RealNetworks tool for creating streaming slideshows based on the RealPix markup.
-
RealSystem
-
The RealNetworks system for streaming media such as RealAudio and RealVideo clips over a network. It consists of RealServer, RealPlayer, and various production tools.
-
RealText
-
A RealSystem clip type (file extension
.rt
) for streaming text over a network. It uses a markup language for formatting text.
-
real-time
-
Delivered as it occurs. For example, a live event is streamed across a network in a real-time broadcast.
-
RealVideo
-
A RealSystem clip type for streaming video over a network. RealVideo clips use the extension
.rm
.
-
rotating banner ads
-
Banner advertisements that change at a specified interval, such as a new ad banner every 30 seconds.
-
RTP
-
Real-Time Protocol. The open, standards-based data package protocol RealServer uses (along with RTSP) to communicate with RTP-based clients. Contrast to RDT.
-
RTSP
-
Real-Time Streaming Protocol. An open, standards-based control protocol that RealServer uses to stream clips to RealPlayer or any RTP-based client. Contrast to HTTP.
S
-
server
-
1. A software application, such as a Web server or RealServer, that sends requested data over a network.
-
2. A computer that runs server software.
-
Shockwave Flash
-
See Flash Player file.
-
SMIL
-
Synchronized Multimedia Integration Language. A markup language for specifying how and when each clip plays within a presentation. SMIL files use the extension
.smil
.
-
stream
-
1. To send a media clip over a network so that it begins playing back as quickly as possible.
-
2. A flow of a single type of data, measured in kilobits per second (Kbps). A RealVideo clip's soundtrack is one stream, for example.
-
SureStream
-
A RealNetworks technology that enables a RealAudio or RealVideo clip to stream at multiple bit rates. Available only in RealSystem.
U
-
URL
-
Uniform Resource Locator. A location description that enables a Web browser or RealPlayer to receive a clip stored on a Web server or RealServer.
V
-
VBR
-
Variable Bit Rate. A type of RealVideo encoding that enables RealPlayer to play different parts of the video at different bit rates, even though the video is being streamed at a constant rate. Contrast to CBR.
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RealNetworks
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This file last updated on 12/12/00 at 15:34:21.