How do you incrementally change the speed of a video clip over time?

What You’ll Need:

>> iMovie ‘11 version 9.0.4 or later
>> clips in an Event or your photo library
>> 25 Minutes

Difficulty: Easy

Making a successful film, whether it’s a big Hollywood blockbuster or a home movie, is all about timing. For action sequences with a lot of energy, you need quick, short clips. Longer shots are usually better suited for emotional scenes.

Even though iMovie is aimed at the casual filmmaker, you still have in your hands a powerful tool that is designed to offer you everything you need to edit fast and with precision. The fact that Apple has adopted the general interface for its new version of Final Cut Pro speaks volumes as to its belief that editing this way is easier than any other method invented, until now.

The philosophy behind this method is to offer you simple tools to get on with building your project, with more advanced features being available by clicking on a button, or by turning on an option for the more complex tools. One such advanced feature is the ability to alter the duration of your clips. This allows you to speed up or slow down the action and is a useful way to change the mood of your clip and project.

You can access this feature from the Inspector window’s Clip tab, but it’s somewhat limited in its capabilities since you can only apply a set speed to your clip. Looking at Final Cut Pro X, you would notice a similar tool, but in this case, you can easily alter the speed within your clip, slowing it down gradually for instance, or making it go faster and faster as it progresses.

You’d expect iMovie to lack many tools that its bigger brother has, but since spending $300 on a program just to gradually speed up a clip isn’t an option for nearly all of us, you’ll be glad to know that there’s a workaround in iMovie that replicates this effect. Obviously, this solution isn’t as seamless, but it works and is easy to achieve. We’ll show you how to do this, teaching you a keyboard shortcut along the way, which will greatly speed up the process.

You’ll need a project to follow the tutorial. You can create a new one or use an existing work in progress. If you’d like to experiment without losing your original edit, select your project in the Project Library section then go to Edit > Duplicate Project, to make a copy of it.

Create a still image out of a moving shot

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How to Change the Speed of a Clip in iMovie

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  1. Manual Splitting

  Add a clip to your project. It should be long enough to have multiple speed increases applied to it. There are two ways you can cut that clip. The first is by dragging across it to create a selection. Use the yellow handles to fine-tune this. Then, go to Clip > Split Clip.

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  2. Keyboard Splitting

  Let’s not alter the first segment’s speed. You can cut the other sections much more quickly with the help of a keyboard shortcut: mouse over the clip without selecting it. Once you’re over the part you wish to cut, use Shift + Command + S. This method saves a lot of time.

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  3. Adjusting

  It’s time to alter each section’s speed. Select a clip then go to Window > Clip Adjustments or simply hit the I key. You may need to convert the clip before your can gain access to its speed controls but performing this action on one segment will affect them all.

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  4. Speeding

  You can change the speed with the slider but it’s hard to control. Instead, click on the value to alter the speed with greater precision. You could change the second clip to 140%, the third to 180%, the fourth to 260%, or any combination you care to use.

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  5. Detaching

  You can now move the cursor to the start of your effect and hit the Spacebar to play it. Change the speed of each individual segment until you get the right feel. Notice the audio has been sped up as well. To avoid this, select the first clip then go to Clip > Detach Audio.

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  6. Muting or Ducking

  An audio track shows underneath that clip. Move the cursor over its right edge then drag it so it stretches across all the other segments. Play back your project now and you’ll hear two audio tracks overlapping one another. You could select each clip individually, but the easiest way is to double-click the detached audio to bring up the Inspector, toggle the Ducking in the Audio tab and drag its slider to the left to mute all clips at once.

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  Quick Tip

  When speeding up or slowing down a clip, any judder, even a slight one, becomes noticeable. Minimize this by Stabilizing your clip. Do this prior to cutting it so you only have to perform the action once. The option is found in the Inspector window.

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