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26 Chapter 3 Making and Editing QuickTime Movies With QuickTime Pro
The duration for each line of text in the text file appears on a separate line before the
line of text. The time you type is the length of time after the movie has started at which
this line of text will appear.
Timestamps are specified as hours:minutes:seconds:fractions of a second (the default
Text to Text export setting is 1/600th of a second). For example, if you enter the time
00:02:11:00, the text on the following line appears at 2 minutes and 11 seconds into
the movie.
For information about the other text track descriptors, see the Developer section of the
QuickTime website at www.apple.com/quicktime.
QuickTime Sprite and Tween Tracks
In traditional cel-based animation, images appear in every frame. With sprite animation,
an image (a sprite) is sent once and the user’s computer draws the image in different
locations as the movie plays. Sprites make it possible to have complex animations with
virtually no bandwidth cost.
To add sprite animation to a QuickTime movie, you create a sprite track in an authoring
program and then import the track into QuickTime. The animation can be an image, a
short image sequence, or a video clip moved around in the frame.
One sprite track can contain multiple sprites. They can pass in front of or behind each
other, and change their depth order (allowing variable visibility) in the course of the
movie. The source for a sprite can be a single bitmap, a bitmap image sequence, a
vector image, a video track, a live stream, or even a source specified by a URL.
A “tween track” modifies other tracks. A tween track is often used with sprite tracks to
specify the animation of the sprite. Tween tracks can also be used for things like
smoothly fading video in or out or turning the movie volume up or down.
Adding a Video Track as a Sprite
You can assign a video track to a sprite track to get the effect of having a video image
move across the screen.
To assign a video track to a sprite track:
1 Create a movie with both the video track and sprite track you want to use.
2 Choose Movie > Get Movie Properties.
3 In the Properties window, choose the sprite track from the left pop-up menu, then
choose Image Overrides from the right pop-up menu.
4 Choose the sprite to which you want to assign a new image, click Select Override Track,
then choose the video track you want to assign to the sprite.
5 Save as a self-contained movie by choosing “Make movie self-contained” in the Save As
dialog. (A self-contained movie contains all data in one file that can be transferred to
another computer.)
LL1158.Book Page 26 Thursday, September 25, 2003 1:26 PM