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About QuickTime Streaming

This chapter discusses the basics of QuickTime streaming and the variety of protocols that can be used to stream QuickTime movies.

Streaming involves sending movies from a server to a client over a network such as the Internet. The server breaks the movie into packets that can be sent over the network. At the receiving end, the packets are reassembled by the client and the movie is played as it comes in. A series of related packets is called a stream.

QuickTime Streaming extends the QuickTime software architecture to support the creation, transmission, and reception of multimedia streams. This allows QuickTime programmers to create applications that receive multimedia in real time, and to create authoring and editing tools that work with streaming content. Existing applications that play QuickTime movies can play real-time streaming movies with little or no code change.

Streaming is different from simple file transfer, in that the client plays the movie as it comes in over the network, rather than waiting for the entire movie to download before it can be played. In fact, a streaming client may never actually download a streaming movie; it may simply play the movie’s packets as they come in, then discard them.

QuickTime movies can be streamed using a variety of protocols, including

• HTTP (Hyper Text Transport Protocol)

• FTP (File Transfer Protocol)

• RTP (Realtime Transport Protocol).

HTTP and FTP are essentially file transfer protocols. Any QuickTime movie saved using the QuickStart option can be streamed using these protocols because the QuickTime client software is able to start playing the movie before the entire file has arrived.

RTP is used for real time streaming. The movie packets are sent in real time, so that a one-minute movie is sent over the network in one minute. The packets are time-stamped, so they can be displayed in time-synchronized order. Because packets are sent in real time, RTP streaming works with live content in addition to previously-recorded movies. It can even carry a mixture of the two.

Real-time streams can be sent one-to-one (unicast) or one-to-many (multicast).

Contents:

Unicast Streaming
Multicast Streaming
Streaming QuickTime Over RTP or HTTP
Multimedia Streaming

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