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

W H A T   I S   S T R E A M I N G   M E D I A ?

The benefi ts of using a specialized streaming media server include:

W H AT   I S    R E A L   T I M E ?  

   More effi cient use of the network bandwidth

   Better audio and video quality to the user 

 Real time  is one of those techie terms we were all 

   Advanced features like detailed reporting and multi stream 

supposed to wake up one day (not so very long ago), 

multi media content 

simply understanding. The implication is that  real time  

means  as it happens,  or  concurrent with reality.  

   Support for large numbers of users 

Since streamed fi les are processed and played back as 

   Multiple delivery options 

they are transferred from server to client, all streaming 

   Content copyright protection

is essentially  real time,  as far as the data is concerned. 

There is, however, always some amount of delay between 

Files that have been encoded in a streaming media format can be served by 

trans mission and reception, making the use of the term 

a standard Web server. Web server streaming, also called HTTP streaming 

 real time,  when it comes to streaming, slightly inaccu 

is, however, actually just a fl avor of progressive download. HTTP streaming 

rate. Transmission of streaming media is dependent upon 

such factors as available bandwidth, connection speed, 

creates a local cached copy of the media fi le, so there is no way to prevent 

and network congestion. And there is often at least a 

end users from copying the fi le into a designated directory on their hard 

momentary delay while the client dependent buffer 

drive. In other words, HTTP streaming does not provide the copyright 

accumulates enough data to process and play. So, espe 

protection for media content that is, by defi nition, an essential characteristic 

cially when media is being streamed to a wide variety 

of true streaming.

of platforms, via the public Internet, each recipient will 

experience playback in a slightly different timeframe 

One interesting advantage of HTTP streaming, however, is its ability to 

not actually concurrently. 

transfer streaming media fi les across fi rewalls which often do not allow true 

streaming media fi les to pass. Many specialized streaming server software 

W H E N   I S    L I V E     L I V E ?

solutions provide streaming media publishers with the option of switching 

over to HTTP streaming when true streaming is prevented by a fi rewall. 

The content of streaming media may be real time 

meaning  live,  as in an event being Webcast as it occurs. 

Streaming is not used to transfer normal data

Or, it may have been stored in an archive and be streamed 

Because audio and video are time dependent mediums, in order for them 

 on demand.  Streaming media may be categorized into 

to play smoothly, packets of information being transferred must arrive on 

three basic program types, based on the kind of content 

time and in good condition. The public Internet, however, is based on an 

streamed and how it is made available to the audience:

asynchronous system, wherein it doesn't matter in what order packets 

VOD ( Video On Demand): When pre recorded 

arrive. Transfer Control Protocol the  TCP  part of TCP/IP ( IP  stands 

streaming media content has been archived on a server, 

it may be accessed   on demand  by individual audience 

for Internet Protocol) typically ensures that fi les are assembled in proper 

members, at any time.  Whenever an end user clicks on 

sequence, and requests replacements for any packets lost or corrupted in 

the link to request the program, it starts playing from the 

transport. This is known as  error correction,  and it is a luxury that is 

beginning.  In similar fashion to viewing a video cassette 

sacrifi ced for streaming as we know it today. When media is streamed, data 

or DVD,  the end user can control the experience by mani 

pulating controls on the player interface to move forward 

that is lost or damaged is gone forever at least as far as that stream is con 

or backward, to pause, or to jump to any point in the 

cerned resulting in imperfect, sometimes even indecipherable, playback. 

program.  Multiple users may be streaming the same 

Fortunately, video is a very  forgiving  medium we tend to get the gist of 

program, but each user may be accessing different 

portions of the content concurrently.

the content, even when it skips a beat or two. So streaming technology is 

still viable when the transmission isn't ideal. Besides, streamies seem to be 

SCHEDULED  WEBC AST:  Archived content may also 

be used for a  scheduled Webcast,  sometimes called 

just as forgiving an audience as the masses who supported the early imple 

a  streaming broadcast.   The designated URL is not valid 

mentations of so many other technologies that have brought us motion 

before the Webcast begins nor after it ends. The host 

and sound scratchy sounding phonograph records; grainy, black and white 

starts streaming the program at a scheduled time, con 

fi lms; early talkies with less than perfect sound synchronization; and the 

tinuing to stream from start to fi nish.  Just like with tele 

vision broadcasts, viewers who don't start to access the 

frustratingly intermittent television reception some of us still recall from 

stream at the appointed time join the program  in prog 

pre cable days. Easily delighted streamies are, apparently, willing to forgive a 

ress.  Scheduled Webcasts are sometimes referred to as 

lot of the jittery, jumpy, jerky qualities of streaming media at its worst. But 

 live Webcasts,  when the audience is  live  for example, 

the point is that streaming is not a reliable way to transfer  normal  data 

on line meetings or distance learning situations in which 

data that must be complete and uncorrupted to be acceptably reproduced on 

parts of the presentation consist of pre recorded stream 

namic Media

ing media and other parts are interactive exchanges (chat, 

the receiving end. So streaming is not used to transfer text fi les, databases, 

y

panel discussions, Q&A, quizzes, etc.)

intricate graphics, and other types of unforgiving information.  

 LIVE  LIVE WEBC AST: When live content is streamed 

Streaming is bandwidth dependent

as it occurs, it is, of course, considered  live.  Like any 

scheduled Webcast, everyone in the audience experiences 

When a non streaming fi le is downloaded, bandwidth is relevant only in 

obe D

the same thing at the same time.  To differentiate a  live 

d

so far as how long it takes for the data to be transferred. A fi le transferred 

Webcast,  (i.e., a scheduled Webcast streaming pre record 

A

over a narrowband (low bandwidth) connection will take much longer to 

ed content to a  live  audience), you'll sometimes hear  as 

download than the same fi le transferred over a broadband (high band 

it occurs   Webcasts referred to as  Live Live. 

7

width) connection, so long as all other factors (such as server load, network