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QuickTime Interactivity

“Interaction can be defined as a cyclic process in which two actors alternately listen, think, and speak.” ––Chris Crawford, computer scientist

This chapter introduces you to some of the key concepts that define QuickTime interactivity. If you are already familiar with QuickTime and its core architecture, you may want to skip this chapter and move on to “Chapter 2, QuickTime VR Panoramas and Object Movies,” which discusses the fundamentals of QuickTime VR, with conceptual diagrams and illustrations of how QuickTime VR movies work. However, if you are new to QuickTime or need to refresh your knowledge of QuickTime interactivity, you should read this chapter.

Interactivity is at the core of the user experience with QuickTime. Users see, hear, and control the content and play of QuickTime movies. The process is indeed cyclic––using Crawford’s metaphor––in that the user can become an “actor” responding alternately to the visual and aural content of a QuickTime movie. In so so doing, QuickTime enables content authors and developers to extend the storytelling possibilities of a movie for delivery on the Web, CD-ROM or DVD by making the user an active participant in the narrative structure.

From its inception, one of the goals of QuickTime has been to enhance the quality and depth of this user experience by extending the software architecture to support new media types, such as sprites and sprite animation, wired (interactive) movies and virtual reality. Interactive movies allow the user to do more than just play and pause a linear presentation, providing a variety of ways to directly manipulate the media. In particular, QuickTime VR makes it possible for viewers to interact with virtual worlds.

The depth and control of the interactive, user experience has been further enhanced in QuickTime on Mac OS X, Mac OS 9, and the Windows platform, with the introduction of cubic panoramas which enable users to navigate through multi-dimensional spaces simply by clicking and dragging the mouse across the screen. Using the controls available in QuickTime VR, for example, users can move a full 360 degrees––left, right, up, or down––as if they were actually positioned inside one of those spaces. The effect is rather astonishing, if not mind-bending.

There are a number of ways in which developers can take advantage of these interactive capabilities in their applications, as discussed in this and subsequent chapters.

The chapter is divided into the following major sections:

• “QuickTime Basics” discusses key concepts that developers who are new to QuickTime need to understand. These concepts include movies, media data structures, components, image compression, and time.

• “The QuickTime Architecture” discusses two managers that are part of the QuickTime architecture: the Movie Toolbox and the Image Compression Manager. QuickTime also relies on the Component Manager, as well as a set of predefined components.

• “QuickTime Player” describes the three different interfaces of the QuickTime Player application that are currently available as of QuickTime 5: one for Mac OX that features the Aqua interface, another for Mac OS 9, and another version for Windows computers.

• “Sprites and Sprite Animation” describes sprites, a compact data structure that can contain a number of properties, including location on the desktop, rotation, scaling, and an image source. Sprites are ideal for animation.

• “Wired Movies” discusses wired sprites, which are sprites that perform various actions in response to events, such as mouse down or mouse up. By wiring together sprites, you can create a wired movie with a high degree of user interactivity.

• “QuickTime Media Skins” discusses how, in QuickTime 5, you can customize the appearance of the QuickTime Player application by adding a media skin to your movie.

• “QuickTime VR” describes QuickTime VR (QTVR), which simulates three-dimensional objects and places. The user can control QTVR panoramas and QTVR object movies by dragging various hot spots with the mouse.

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