Wired Movies and Sprites

Supported Modifier Inputs

In addition to receiving image data, a sprite track can receive modifier track data to control its sprites. The following modifier inputs are supported:

images from a video track (kTrackModifierTypeImage )
a matrix from a base track (kTrackModifierObjectMatrix )
a graphics mode from a base track (kTrackModifierObjectGraphicsMode )
an image index from a base track (kTrackModifierObjectImageIndex )
an object layer from a base track (kTrackModifierObjectLayer )
an object visible from a base track (kTrackModifierObjectVisible )

For example, a modifier track can send matrices to individual sprites to control their locations. To do this, you set up a modifier track, such as a tween track, to send matrix data to the sprite track. You must update the sprite media's input map with an atom that specifies the input type (kTrackModifierObjectMatrix ) and an atom that specifies the ID of the sprite to replace (kTrackModifierObjectID ). If the sprite track also contains matrices to move the sprites, the results are undefined.

With the exception of image data, the source for all modifier tracks can be tween or base tracks.

For background information on modifier tracks, see Chapter 1, "Movie Toolbox," in QuickTime 4 Referen ce.