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Chapter 12: Animation
Animating effects
About keyframes
Keyframes
are used to create and control animation, effects, audio properties, and many other kinds of change that
occur over time. A keyframe marks the point in time where you specify a value, such as spatial position, opacity, or
audio volume. Values between keyframes are
interpolated
. When you use keyframes to create a change over time, you
must use at least two keyframes—one for the state at the beginning of the change, and one for the new state at the
end of the change.
Working with keyframes
When you use keyframes to animate the Opacity effect, you can view and edit the keyframes in either the Effect
Controls or the Timeline panel. Sometimes, the Timeline panel alternative can be more appropriate for quickly
viewing and adjusting keyframes. The following guidelines may indicate the appropriate panel for the task at hand:
•
Editing keyframes in the Timeline panel works best for effects that have a single, one-dimensional value, such as
opacity or audio volume. The Effect Controls panel is usually easier for editing keyframes of effects that have
multiple, angular, or two-dimensional values, such as Levels, Rotation, or Scale, respectively.
•
In the Timeline panel, variations in keyframe values are indicated graphically, so you can see at a glance how
keyframe values change over time. By default, values change between keyframes in a linear manner, but you can
apply options that refine the rate of change between keyframes. For example, you can bring motion to a gradual
stop. You can also change the interpolation method and use Bezier controls to fine-tune the speed and smoothness
of an effect’s animation.
•
The Effect Controls panel can display the keyframes of multiple properties at once, but only for the clip selected
in the Timeline panel. The Timeline panel can display the keyframes for multiple tracks or clips at once but can
display the keyframes of only one property per track or clip.
•
Like the Timeline panel, the Effect Controls panel also displays keyframes graphically. Once keyframing is
activated for an effect property, you can display the Value and Velocity graphs. The Value graph displays keyframes
with changes in an effect’s property values. The Velocity graph displays keyframes with handles for adjusting the
speed and smoothness of the value changes from keyframe to keyframe.
•
Keyframes for audio track effects can be edited only in the Timeline panel or in the Audio Mixer. Keyframes for
audio clip effects are like keyframes for video clip effects; they can be edited in the Timeline panel or in the Effect
Controls panel.
You can modify the panel arrangement further and choose Window > Workspace > Save Workspace to save the
modified configuration as your own workspace. Be sure to give your workspace a name in the Save Workspace dialog
box before clicking the Save button.