QuickTime 4 Reference

Creating a Tween Track

To create a tween track, you must:

Create a tween track and its media.
Create one or more tween media samples.
Add the media samples to the tween media.
Add the tween media to the track.
Create a link from the tween track to the track to which the tween media handler should send tween values.
Bind the tween entry to the desired attributes in the receiving track.

The sample code shown in this section creates a tween sample that interpolates a short integer from 255 to 0. The tween media is attached to the sound track of a QuickTime movie to modify the sound track's volume. Thus it creates a volume fadeout using the tween track. The data type for the tween component is kTweenTypeShort.

The sample code shown in Listing 1 creates a new track (t ) to be used as the tween track and new tween media (type TweenMediaType ).

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