Road Map to QuickTime 3

Tween Media Handler Components

This chapter describes the tween media handler and a set of functions you can implement to create a tween component. The tween media handler and tween components were introduced in QuickTime 2.5.

The tween media handler is a track that is used exclusively as a modifier track. It is used to algorithmically generate values to modify the playback of other tracks. The tween media handler sends values to other media handlers; it never presents data. For information about modifier tracks, see Movie Toolbox.

The tween media handler only requires a start value and an end value to be specified. The intermediate values are generated automatically, typically by linear interpolation.

New features of the tween media handler for QuickTime 3 are not fully documented at this time. This chapter documents the tweener functionality as of QuickTime 2.5. All of the information provided here is still valid, but additional features remain to be documented.

QuickTime 3 Reference gives a concise overview of the tween media handler and tween components.

QuickTime 3 Reference describes how to create a tween track and how to create a tween component. Detailed code examples are provided.

• Creating a Tween Track
• Creating a Tween Component

QuickTime 3 Reference defines the constants used by the tween media handler. This includes several predefined data structures that might be considered data types as easily as constants.

• Tween Component Constant
• Tween Atom Types
• Media Input Map
• Tween Data Types

QuickTime 3 Reference defines the data types used by tweener media handler components.

• Component Instance
• Tween Record

QuickTime 3 Reference defines the functions provided by tweener media handler components. Note that the value setting function is called as a universal procedure or a data procedure, rather than as a straight function call.

• TweenerInitialize
• TweenerReset
• TweenerDoTween
• Value Setting Function