How do I add a mask in iMovie 2025?

iMovie does not have a mask feature so you will have to use a rather complex workaround as detailed in this AI generated response.

AI Overview

Adding a mask in iMovie in 2025 (Mac) requires using the Picture-in-Picture (PiP) feature combined with a specially prepared image file (such as a PNG with transparency) to create a custom shape, or using the "Cutaway" tool to blend two clips. iMovie does not have a dedicated, one-click masking tool like professional editors, so this workaround is used for effects like blurring, cropping in custom shapes, or placing text behind subjects. 

Methods for Adding a Mask in iMovie (2025):

• Custom Shape/Logo Mask (PNG Method):

1. 1. Create a black-and-white shape or image (mask) in a program like Keynote or Photoshop and save it as a .png file with transparency.
   2. Place your main video clip on the timeline.
   3. Drag the PNG mask file on top of your main clip in the timeline.
   4. Select the PNG file, click the Video Overlay Settings button above the viewer, and change the setting to Picture in Picture.
   5. Adjust the position and size of the PNG to cover the area you want to mask.

• Using "Cutaway" for Transparency:

1. 1. Place two clips on the timeline, one on top of the other.
   2. Select the top clip and change the overlay setting to Cutaway.
   3. Adjust the opacity to make the clip semi-transparent if needed, allowing for a blending effect.

• Blurring a Moving Object (Masking):

1. 1. Take a screenshot of the frame you want to blur, then use an image editor to blur that area.
   2. Import this blurred image and drag it over your video in the timeline.
   3. Set it to Picture in Picture and use keyframes to make the blur follow the object.

• Green Screen/Masking on iPhone:

1. 1. On the mobile app, add a clip over another, then tap the Mask button (often within the Green/Blue Screen settings) to drag corners and exclude parts of the image.

• Keynote Mask Method:

1. 1. Create animated text or shapes in Keynote, export it as a movie file, and import it into iMovie to act as a moving mask. 

To create a "stencil" effect, you can also use black-and-white images to define which areas of the video are visible, with the brighter areas showing the foreground and darker areas showing the background. 

However, if you download the FREE version of DaVinci Resolve you will have access to masks and most pro features.

The only downside is that DVR has quite a steep learning curve but if you search YouTube for Masking in Resolve you should find several tutorials.

Download Resolve