Apple QuickTime Streaming Server Darwin Streaming Server manual How Does Streaming Work?

A PowerBook G4 with QuickTime Broadcaster software captures and encodes video and audio. The encoded signal is sent over an Internet Protocol (IP) network to a server computer running QTSS or DSS software. QTSS or DSS on the server computer sends the signal over the Internet or a local network to client computers that tune in using QuickTime Player.

You can also run QuickTime Broadcaster and QTSS or DSS on the same computer. If you are broadcasting to a large audience (more than, say, 100), however, Apple recommends that you run QuickTime Broadcaster and QTSS or DSS on separate computers.

How Does Streaming Work?

When you watch and listen to cable or over-the-air media transmissions on television or radio, the cable or electromagnetic wavelengths used are dedicated to that transmission. Those transmissions are mostly uncompressed and so consume large amounts of transmission bandwidth. But that’s not a problem, because they don’t have to compete with other transmissions within the frequency over which they’re broadcast.

When you send that same media over the Internet, the bandwidth used is no longer dedicated to only that transmission stream. The media now has to share extremely limited bandwidth with thousands, potentially millions, of other transmissions traveling back and forth over the Internet.

Multimedia sent over the Internet is therefore encoded and compressed for transmission. The resulting files are saved in a specific location, and streaming server software such as QuickTime Streaming Server or Darwin Streaming Server is used to send the media over the Internet to client computers.

Streamed media can be viewed by both Macintosh and Windows users using QuickTime Player (available free on the Apple web site) or any other application that supports QuickTime or standard MPEG-4 files. Streams can also be set up so that users can view them from within a web browser when the QuickTime plug-in is installed.

When a user starts to play streamed media through a web page, the QuickTime plug-in sends a request to the streaming server. The server responds by sending the multimedia content to the client computer.

The type of multimedia that is sent to the client computer depends on what content you specified on the web page. If you linked to a playlist created on the streaming server, that’s sent. If you linked to a QuickTime movie in the specified media directory, that movie is sent. If you linked to a live broadcast, that’s sent.

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