Corporate Coordinators

Streaming is the transmission of real-time data, commonly audio and video, from a server to a client where the client "plays" or decodes the data as it is received. This differs from downloaded, data which is played after being received in full.

Streaming lets the viewer sees the content immediately after a short buffering period, which can be as little as 5-20 seconds. The buffer allows the player to maintain continuous playback in the event of minor network congestion:

A simple analogy is today's "shock-resistant" portable CD players. These CD players store 3-5 seconds of a track from a CD in their memory, so if the player gets bumped, it doesn't skip. Streaming video works the same way. The player keeps a buffer and if there is any network congestion (a "bump") the player can keep playing without stopping. A streaming video player stores more in memory than the CD player because network congestion can last several seconds.

With streaming video, you can offer video and audio over the Internet or over a variety of local and wide-area networks. Your streaming video can be a live broadcast of an event or presentation, or 'on-demand' playback of prerecorded video (a RealMedia file). (Note that when the term Streaming Video is used, it generally means audio and video combined. Streaming Audio is just that, audio only.)

Now, a little about the Internet. Data on the Internet is sent in packets, each one bearing the address of the sender and the receiver. You have probably seen these addresses and they read something like this '4.21.232.113' (the address of this site). There are many nodes on the Internet and they pass the message from one to the other until it reaches its destination. If you want to see the path that your messages are traveling across the Internet to reach this site, you can use the DOS command 'TRACERT www.AllianceWWW.com'. You will receive a list of all the nodes that your message passed through while coming to the site.

The Internet is lossy, non-deterministic and elastic. In plain English, this means that packets may get lost, that packets may go by different paths and that the system as a whole adjusts itself continuously to local loading conditions. The result is that the amount of time it takes one packet of information to go from your machine to the host is not necessarily the same as the time that will be taken by the packet after it or that before it. If you receive the message 'Net Congestion, Buffering', it means that you do not have large enough buffers to compensate for the uncertainties in Internet delivery. You can reduce the incidence of the 'net congestion' message by changing the buffering on your real player so that the buffers are bigger. Then intermittent loss won't bother the stream as much.

You can do this by going bringing up your RealPlayer, positioning over it and clicking the right mouse button. Select the menu option titled 'preferences', then select the tab labeled 'connection.' The section labeled 'buffered play' allows you to change the amount of data that is stored during streaming. If you make your buffers bigger, streaming video will take a little longer to start playing (because bigger buffers will have to be filled, which takes longer), but the playback may be smoother.