Apple Final Cut Express HD - Manual (Page 720)

720 Part IX Effects
Since you can add keyframes to filters and generators, as well as motion settings, the
information presented in this chapter can also be used to modify filters and generators
(discussed in Chapter 48, “
Video Filters ,” on page 663 and Chapter 57, “ Using Built-in
Generated Clips ,” on page 849).
How Keyframing Works
You place keyframes at specific points in a clip or sequence to change parameters at
those points. For example, if you want the last clip in your sequence to fade to black,
you set two Opacity keyframes at two different times: one with the value of 100 (fully
visible) and a second with the value of 0 (fully transparent). Final Cut Express HD
interpolates the values between 100 and 0, creating a smooth fade to black. To add
keyframes to a sequence clip, you can use the Canvas and Timeline.
Note: You can also add keyframes to master clips that are opened into the Viewer from
the Browser, but these keyframed effects accompany the clip whenever it’s edited into
a sequence.
When you use two or more keyframes to change an effect over time, Final Cut Express HD
automatically interpolates the values between the keyframes so that there’s a smooth
change in that parameter. For example, when you look at a clip with a change in opacity
using two keyframes, you can see the gradual change from one keyframe to the other in
the slope of the Opacity overlay, as shown below in the Timeline.
Adding additional keyframes increases the complexity of the effect, but the area in
between each pair of keyframes in your clip is still smoothly interpolated.
First
keyframe
Overlay in the Timeline for
the Opacity parameter Second
keyframe
Using more keyframes
creates additional
complexity, shown
in the overlay.