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Basics of Using QTKit Capture

The QuickTime Kit framework was developed by Apple to provide support for the most common media-related tasks of Cocoa and QuickTime developers. This support was accomplished by using certain abstractions and data types familiar to Cocoa programmers and by defining other abstractions and data types that were new––but only where necessary. The goal was to provide high-level Cocoa interfaces for playing and editing, importing and exporting various types of media. In response to the growing needs of the developer community, new methods have been added with each release to the five base classes that comprise the framework.

Now with the introduction of Mac OS X v10.5 and the latest iteration of QuickTime 7, the QuickTime Kit framework has made a major leap forward, providing support for capturing media from external sources, such as cameras and microphones, and outputting that media to QuickTime movies. Fifteen new classes have been added to the existing five in the first iteration of the framework. The goal is to provide Cocoa and QuickTime developers with a viable and robust alternative to using the procedural C sequence grabber API, which allowed applications to obtain digitized data from external sources, such as video boards. Using the QTKit capture API is now the preferred way of developing applications that support capture and recording of media.

This chapter describes at a basic level the QTKit capture architecture and implementation available in Mac OS X v10.5. You’ll gain an understanding of how you can capture, record, and output to various destinations by reading this chapter. Recording from an iSight camera or another DV device to a QuickTime file, for example, is one of the most common uses for the QTKit capture API.

To take advantage of this new API, you’ll need to read this chapter first before moving ahead to the following chapters which describe how to build a QTKit capture player application.

Contents:

Tasks Supported by QTKit Capture Classes
How QTKit Capture Works
Using the QTKit Capture API
Base Classes
Input and Output Classes
Utility Classes
Device Access and User Interface Classes

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