QuickTime 4 introduced support for receiving real–time streamed data. That is to say, QuickTime–savvy applications can receive video, audio, and other kinds of data streamed across the Internet. Real–time streaming, unlike the progressive downloading of movie files that has been available since QuickTime 3, can handle live data and does not require downloading potentially huge files onto the user’s computer; this permits QuickTime playback applications to support uses such as video–on–demand and rebroadcast streaming.
The real–time streaming provided by QuickTime 4 was a client–side technology only; it did not provide any means to serve up, or transmit, the data streams. QuickTime 5 provides a set of broadcasting functions that allow us to create transmitter applications. For example, we can take the audiovisual data captured by a camcorder attached to one computer and broadcast that data to other computers on a network. Together, the transmitter technologies provided by QuickTime 5 and the receiver technologies provided by QuickTime 4 give us the complete set of tools we need to send audiovisual streams from one computer and view them on another. The good news here is that we need to know virtually nothing about the applicable IETF specifications to do all this; the really good news is that the amount of code we need to write to create a broadcasting application is surprisingly small. Indeed, we'll be able to write this application using fewer than a dozen of these new broadcasting functions.
The Real–Time Streaming Framework featured by the QTPlugin is a set of classes that allow developers to gain access to both the transmitter and receiver technologies provided by the QuickTime APIs within the Realbasic environment.
The QTPlgStreamSessionVideoParams utility class is part of the Real–Time Streaming Framework and is used to specify the characteristics of the visual streams that have to be sent or received from a .
Using this class requires QuickTime 4.0 or later.
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The QTPlgStreamSessionVideoParams class constructors are called when you create a new instance of the class, while the ˜QTPlgStreamSessionVideoParams class destructor, is called automatically when the class is no more in use. Also, you can invoke the class destructor by setting the instance of the class to nil.
Once a new class instance is returned, it is good practice to check the class property to be sure that the new object can be used. An instance of this class is valid if it has been set a for the display of the streamed data (whether received or transmitted).
The class provides you with the following initializer methods: