iMovie for Mac: Use a green-screen or blue-screen effect to superimpose one clip over another

Use a green-screen or blue-screen effect to superimpose one clip over another

You can record video in front of a green or blue backdrop, and then “cut out” the subject and superimpose it over another video clip. This is called a green-screen or blue-screen effect. For example, you could record a friend dancing in front of a green or blue backdrop, and then place that video over a clip showing a starry sky, so that your friend appears to be dancing in the sky.

You can also drag the green-screen or blue-screen clip over a solid-color or animated background clip.

If the subject of your video is green or is wearing green, you should record in front of a blue background. Likewise, if the subject of your video contains blue or is wearing blue, you should record in front of a green background.

The audio from the original clip and the audio from the green-screen or blue-screen clip play simultaneously. You can reduce the volume of either clip so that sound from the other clip stands out. For more information, see Apply audio effects to clips.

Use a green-screen or blue-screen effect

  1. In the timeline, select a clip or range that you shot against a green or blue backdrop, and drag it above a clip in your project.

    When you see the green Add icon (+), release the mouse button.

    Timeline showing clip being dragged above another clip to connect it
  2. If the video overlay controls aren’t shown, click the Video Overlay Settings button.

    Video Overlay Settings button in adjustments bar
  3. Click the pop-up menu on the left and choose Green/Blue Screen.

    In the viewer, the clip shot against the green or blue backdrop has the green or blue removed, and the clip below shows through the areas that were green or blue, creating a composite image.

    The color that iMovie removes is based on the dominant color in the frame at the position of the playhead when you choose Green/Blue Screen from the pop-up menu. If the frame below the playhead isn’t representative of the rest of the clip, you may need to reposition the playhead and reapply the effect.

    To reposition the green-screen or blue-screen clip, drag it to a different spot within the clip, or to a different clip. You can also drag the ends to lengthen or shorten it.

  4. To apply the changes, click the Apply button in the Green/Blue Screen controls.

Adjust a green-screen or blue-screen effect

  1. Select the green-screen or blue-screen clip you want to adjust.

  2. If the Green/Blue Screen controls aren’t shown, click the Video Overlay Settings button.

    Video Overlay Settings button in adjustments bar
  3. Do any of the following:

    • Adjust the softness of the edges of the superimposed clip: Drag the Softness slider.

      Green/Blue Screen controls
    • Isolate areas of the green-screen or blue-screen clip: Click the Crop button, and then drag the corners of the frame to isolate the subject in the foreground clip.

    • Clean up areas of the green-screen or blue-screen clip: Click the Clean-up button, and then drag across stray parts of the green-screen or blue-screen clip that should not be showing.

      Each time you drag, iMovie uses the new selection to determine what should be cleaned up.

      Tip: You should set Softness before clicking the Clean-up button. If you adjust Softness after you use the Clean-up button, the background clean-up selection is reset and must be reselected.

  4. To apply the change, click the Apply button in the Green/Blue Screen controls.

Published Date: Oct 6, 2017
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