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Road Map to QuickTime 4

Tween Media Handler

This chapter describes the tween media handler. The tween media handler uses data from tween tracks to modify the playback of other tracks. It does this by sending values to other media handlers; it never presents data directly. A tween track is used exclusively as a modifier track. For an introduction to modifier tracks, see Movie Toolbox: Creating and Saving.

Modifier data from a tween track is generated by algorithm. It requires only a start value and an end value to be specified. The intermediate values are generated automatically, typically by linear interpolation. To generate the intermediate values, the tween media handler invokes a tween component (or native QuickTime code). For more information, see Tween Components.

QuickTime 4 Reference gives a brief overview of the tween media handler.

QuickTime 4 Reference describes how to create a tween track and how to connect a tween track to the input map of the track(s) it will modify. Detailed code examples are provided.

• Creating a Tween Track
• Creating a tween track and tween media
• Creating a tween sample
• Adding the tween sample to the media and the media to the track
• Creating a link between the tween track and a receiving track
• Binding a tween entry to its receiving track

QuickTime 4 Reference defines a QT atom type used for mapping a tween to the receiving track of a movie.