Speed Basics

The default speed of all clips is 100 percent, but you can change a clip’s speed setting at any time.

You can apply constant speed changes as you can when working with slow-motion or fast-motion changes, or you can create variable speed changes to create sophisticated effects.

Constant Speed Changes on Entire Clips

Applying a constant speed change to an entire 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 you’re altering a clip’s timing to fit a larger or smaller gap in your sequence, or when you’re trying to achieve a consistent speed change across an entire clip (making a car seem faster or slower, for example) or a group of clips.

Tip: If you are using a Change Speed dialog to adjust a clip to a specific duration, use the Duration field rather than the Rate field to maximize precision. For more information, see About the Change Speed Dialogs.

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 Pro. For more information about rippling clips in a sequence, see Performing Slip, Slide, Ripple, and Roll Edits.

A constant speed change over an entire clip changes the duration of the clip. If you choose 50 percent speed, your clip is twice the duration; if you change speed to 200 percent, the clip becomes half as long. For example, if you set a 10-second clip to play back at 50 percent speed, Final Cut Pro duplicates frames in the clip so that the clip becomes 20 seconds long and plays back more slowly. If you increase the clip’s speed to 200 percent, Final Cut Pro skips frames and makes the clip 5 seconds long, and it plays back considerably faster.

Figure. Timeline windows showing the same clip being lengthened from 10 seconds to 20 seconds because of a 50 percent speed change.

Note: Speed settings are applied to the specific instance of the selected clip only. They are not applied to that clip’s source media on disk and can be changed at any time. To create an (external) media file with the applied speed effects, export the clip as a QuickTime movie.

Variable Speed Changes

Applying variable speed to a clip allows you to dynamically alter the speed of a clip over time, in forward or reverse motion. Variable speed allows you to create sophisticated effects in which subjects appear to smoothly shift across a variety of different speeds, with hard or gradual transitions between each change. To create variable speed effects, you create speed segments, essentially segments of a clip that begin and end with speed keyframes.

Variable speed also allows you to create a smooth transition when going from normal speed to fast or slow motion. These types of effects can be seen in many music videos and broadcast commercials, and the effects can be created directly within your edited sequences without your having to resort to an external compositing application.

Variable speed cannot be applied to the following:

  • Audio

  • Nested sequences

  • Still images

  • Multiclips