Apple Final Cut Express 4 - Manual (Page 789)

Chapter 50 Changing Clip Speed 789
IX
Constant Speed Settings
Applying a constant speed change to a clip alters the entire clip’s playback speed by
the same percentage. For example, applying a speed setting of 25 percent to a clip
makes the entire clip play in slow motion. Constant speed changes are useful when
altering a clip’s timing to fit a larger or smaller gap in your sequence, or when trying to
achieve a consistent speed change across an entire clip (making a car seem faster or
slower, for example).
Constant speed changes also alter the duration of a clip. If a constant speed change
causes the duration of a clip in a sequence to become longer or shorter, all clips
coming after it ripple forward or backward according to the ripple editing rules in
Final Cut Express. For more information about rippling clips in a sequence, see
Chapter 33, “
Performing Slip, Slide, Ripple, and Roll Edits ,” on page 483.
Frame Blending and Reverse Speed
Duplicating frames to create slow motion can result in a strobing, jittery effect. To
minimize this, you can turn on frame blending in the Speed dialog. When slow motion
is created, frame blending uses the two frames that appear to either side of duplicate
frames and creates new in-between frames that are a composite of both. When
blended frames are inserted in place of frames that have simply been duplicated,
slow-motion clips appear to play back more smoothly. Speed changes can still play
back in real time with the Frame Blending option turned on.
Note: While clips using frame blending can play in real time at preview quality, frame
blending on a field-per-field basis is much more processor-intensive and is only
performed when the clip is either rendered or played via a third-party video interface
with real-time hardware processing that’s capable of field blending.
You can make a clip play backward by selecting the Reverse option. Alternatively, you
can enter a negative speed setting.
Note: Frame blending and reverse speed can be applied to constant speed clips.
Original Blended frame Original