Apple Final Cut Pro 5 - Manual (Page 1102)

Chapter 16 Changing Clip Speed and Time Remapping 315
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Making Variable Speed Changes
Time remapping allows you to make variable speed changes in clips. You can move any
frame in a clip’s media file so that it plays at some other time in a clip. Adjacent frames
automatically shift position in time, causing speeding up and slowing down to
compensate for the moved frame or frames.
Variable speed changes are made by assigning a frame in a clip’s media file to a new
time in the clip. All the other frames are repeated or skipped accordingly to
compensate, which causes fast or slow motion. This is known as time remapping,
because you are changing when during a clip the frames play back.
Time remapping parameters can be keyframed. When you add a time remapping
keyframe, you choose which frame from a clip’s media file is shown at a particular time
in the clip. You can add keyframes directly in the keyframe editor in the Timeline or the
Motion tab in the Viewer. You can also use the Time Remap tool to intuitively drag a
clip’s media file frame to a new time in the clip.
How Time Remapping Works
The goal with time remapping is to make a particular frame from your media file occur
at a specific point in the Timeline. For example, suppose you have a clip at the
beginning of a sequence in which a diver hits the water at frame 90 of the clip’s media
file. Suppose you have a musical cue at frame 300 in the sequence. You can use time
remapping to move frame 90 of the clip’s media file to frame 300 of the sequence clip.
To compensate, Final Cut Pro must slow down the media frames to make 90 frames last
for the duration of 300. You need only to remap a single frame in time, and
Final Cut Pro adjusts the rest of the clip’s speed accordingly.
Under most circumstances, a clip plays back frames from its media file in chronological
order. If you have a 300-frame clip, it begins by playing frame 1 of the media file, then
frame 2, 3, and so on, until frame 300. Time remapping allows you to adjust when
frames of a clip’s media file are played back by changing their chronological order,
skipping some frames (fast motion), or repeating others (slow motion).
It may help you to think of the process of time remapping as frame remapping, since what
you are doing is mapping the frames of a clip’s media file (input frames) to different times
in the clip (output frames). You need to set only a few keyframes, and Final Cut Pro
interpolates the rest automatically, creating smooth speed changes over time.