A   S t r e a m i n g   M e d i a   P r i m e r :  

G L O S S A R Y

bit rate: In a digital network, the number of bits that 

 jump,  at will, during playback, so long as chapteriza 

pass a given point, in a given amount of time, usually a 

tion is supported by the video architecture in use. True 

second. Bit rate is usually measured in kilobits (Kbps), 

streaming of video supports chapterization; pseudo 

or thousands of bits per second. While the term  bit 

streaming, a.k.a. progressive download, does not.

rate  is a synonym for data transfer rate (aka data rate), 

client: In a client/server architecture, the client is a 

bit rate seems to be used more often when referring to 

software application that makes requests of the server 

telecommunications transmission technology, and data 

on behalf of the end user. A Web browser  is a client 

transfer rate (or data rate) is used more often when 

application; a media player is also a client application. 

referring to computing systems.

Sometimes the term  client  is also used to refer to 

bluescreen: Video editing technique used to combine 

a PC or workstation (hardware) on a network being 

a subject with a background shot separately. The subject 

used by an individual to access data and or applications 

is shot against a solid blue (or sometimes green) color 

hosted on a server.

screen. The blue color can be selected on a frame by 

clip: A digitized portion of media, typically video or 

frame basis, through the use of a video editing system. 

audio.

A matte can then be generated to isolate the subject, in 

order to composite it onto the desired still or motion 

clipping:  Clipping occurs when audio volume reaches 

background clip.

or exceeds 0 decibels (db) for 3 consecutive seconds. If 

you don't lower the volume so it is within the clipping 

broadband: High bandwidth network (Internet or 

threshold, data will be lost.

intranet) connections higher than 56 Kbps (e.g., ISDN, 

DSL, cable modem, T 1).

codec:  Short for compressor/decompressor; comprised 

of algorithms that handle the compression of video to 

broadcast: A single stream transmitted to all clients 

make it easier to work with and store, as well as the 

on a network, whereby all the clients experience the 

decompression of video for playback.

same portion of the media program, at the same time, 

whether the program is live or pre recorded.

co location: An outsource, usually a dedicated facility 

or facilities, that provides physical space for and/or 

broadcast quality: Standard of quality associated 

shared usage of essential computer equipment such 

with current expectations of clearly received network 

as Web servers and, often, mission critical managed 

or cable television. 

services. Co locations typically provide a high level of 

browser: A client application, usually with a graphical 

security and protection against fi re, theft, vandalism, 

user interface (GUI), that provides a way to experience 

power outages or irregularities, and other risks which 

and interact with fi les hosted on a network, such as the 

might, potentially, devastate a business that is reliant 

Internet or an intranet. Web browsers provide access 

on 24/7/365 computer operations. 

via the Internet to fi les posted on the World Wide 

compositing:  The process of combining two or more 

Web. Web browsers use the Hypertext Transfer Protocol 

images to yield a resulting, or  composite  image.

(HTTP)  to make requests of Web servers connected 

to the Internet, on behalf of the browser user. The 

compression: Algorithms used by a computer to 

two most popular browsers in use today are Netscape 

reduce the total amount of data in a digitized frame or 

Navigator and Microsoft Internet Explorer.

series of frames of video and/or audio.

buffer: A temporary storage area, or holding place, 

datagram: See packet.

usually in the RAM (random access memory) of a 

data rate or  data transfer rate: Amount of data 

computer or peripheral device (e.g., a printer), where 

moved over a period of time, such as 10MB per second. 

data can be collected and/or held for ongoing or later 

Often used to describe a hard drive's ability to retrieve 

processing. 

and deliver information.  Also see bit rate.

byte: Eight (8) bits.

de interlacing: The process, usually performed by 

camcorder:  A video camera, i.e., a device that records 

video editing software, of removing interlacing from 

continuous pictures and generates a signal for display or 

video originally intended for display on television 

recording. To avoid confusion, it is recommended that 

monitors, in order to make it suitable for display on 

the term  camcorder  be used rather than  camera  in 

computer monitors.

contrast, a digital camera records still images, while a 

delta frame: In interframe (a.k.a. temporal)  com 

digital camcorder records continuous video images.

pression, periodic keyframes store all the information 

capture:  If the source footage is analog,  capture  

that comprises a frame, while delta frames store only 

refers to the act of digitization (conversion to a digital 

the information that changes from frame to frame in 

format) to make the video usable on a computer and, 

between keyframes.

usually, the simultaneous application of compression to 

digital: In contrast to analog, digital representations 

namic Media

reduce the video to a manageable data rate for process 

consist of values measured at discrete intervals. Digital 

y

ing and storage. If the source video is DV,  capture  

clocks go from one value to the next without displaying 

typically refers to the simple transfer of video from 

all intermediate values. Computers are digital machines 

an external device, such as a digital camcorder or tape 

employing a binary system, i.e., at their most basic level 

deck, to a computer hard drive.

they can distinguish between just two values, 0 and 1 

(off and on); there is no simple way to represent all the 

obe D

capture card:  A printed circuit board that fi ts into an 

values in between, such as 0.25. All data that a computer 

d

expansion slot on a computer and provides functional 

processes must be digital, encoded as a series of zeroes 

A

ity for capturing video from an external source.

and ones. Digital representations are approximations 

chapterization: The process of placing markers into 

of analog events. They are useful because they are 

the timeline of a video to demark the beginning points 

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relatively easy to store and manipulate electronically. 

of sequences, or chapters, to which a viewer may