---

Building a Simple QTKit Capture Application

In this chapter, you’ll build a QTKit capture player, a simple yet powerful application that demonstrates how you can take advantage of some of the new capture classes and methods available in the next iteration of the QuickTime Kit framework. When completed, your QTKit capture player application will allow you to capture a video stream and record the media to a QuickTime movie. You won’t have to write more than 20 or 30 lines of Objective-C code to implement this capture player.

Using Xcode 3 as your integrated development environment (IDE), along with Interface Builder 3, you’ll see how easy it is to work with the QuickTime Kit framework. In this example, you’ll use the new QTKit capture control provided in the library of controls available in Interface Builder 3. The QTKit capture control will perform much of the work for you in implementing the design of the user interface for this application.

Following the steps in this guide, you’ll be able to build a functioning capture player application that controls the capture of QuickTime movies, adding simple start and stop buttons, and allowing you to output and display your captured files in QuickTime Player. For this project, you’ll need an iSight camera, either built-in or plugged into your Macintosh. You’ll also need Mac OS X v10.5, the latest release of Mac OS X, installed in your system.

In building your QTKit capture application, you’ll work with the following three classes:

• QTCaptureSession. The primary interface for capturing media streams.

• QTCaptureMovieFileOutput. The output destination for a QTCaptureSession object that writes captured media to QuickTime movie files.

• QTCaptureDeviceInput. The input source for media devices, such as cameras and microphones.

For purposes of this tutorial, you won’t need to have a complete understanding of the methods that belong to these capture classes. As you extend your knowledge of the QTKit framework, you should refer to the QuickTime Kit Framework Reference, which describes in detail the methods, notifications, attributes, constants, and types that comprise the collection of classes in the QTKit API.

Contents:

First Steps
Create the Project Using Xcode 3
Create the User Interface Using Interface Builder 3
Set Up a Preview of the Captured Video Output
Wire the Start and Stop Buttons
Complete the Project Nib File in Xcode
Implement and Build Your Capture Application

---