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Using iMovie: Basics

How to do basic editing and chroma key (green screen) replacement.

About iMovie

iMovie is a video editing program from Apple Computers. It comes with all macOS Computers. These tutorials will cover basic editing with iMovie: trimming video and replacing green screen backgrounds.

For more advanced instruction, visit

Creating a New Project

Creating a new Project

In the project tab, select Create New and then Movie, or select New Movie from the File menu.


Click Import Media or Select Import Media from the File Menu

Navigate and select your videos to import

Drag your clips to the timeline in the order you would like them.

Trimming a Video Clip

Trimming a Clip

To trim a clip, place the cursor at the beginning or end of the clip and then drag right or left.

If you need to use different pieces of the same clip, you can drag multiple copies of that clip onto the timeline and trim & arrange as needed.

Exporting Video to MP4

Exporting Video to MP4

Select File -> Share -> File...

Enter in a tile, description, and other metadata for the video.

If you only need Audio from the recording, select Audio Only. Otherwise, leave Video and Audio Selected.

Then click Next ...

Select where you'd like to save your video.

Depending on how long or how many edits to the video you've made, it could take several minutes for iMovie to encode and write your video. You can monitor iMovie's progress by clicking the status timer in the top right of the iMovie window.

Basic Troubleshooting

Where's the sound for my video?

If you are using the iMac in the One Button Studio to edit your video, you may not hear audio. This happens because the iMac defaults to using the studio projector for audio whether the projector is on or not. To Fix this:

Click on the Apple Menu and select System Preferences

Select Sound from the System Preferences


In the Sound window, select the Output tab and then select Internal Speakers. You should hear audio from your video.