Apply a shape mask to a video effect

You can define the area of a video effect, including a color correction, using the powerful shape-masking tool.

In the example below, you can apply an effect (such as Gaussian) to everything outside or inside the mask shape that you define.

Viewer showing Shape Mask onscreen controls and Gaussian effect

You can add multiple masks to define multiple areas, and you can also animate the shapes so that they follow an area while a camera pans or an object moves as the clip plays.

Apply a shape mask to a video effect

  1. Add a clip to your project and select it in the Timeline.

  2. Position the playhead in the Timeline so that your clip appears in the Viewer.

  3. Add an effect to the Timeline clip from the Effects Browser.

    Note: This includes the Color Correction effect, which you can apply from the Color category of the Effects Browser or from the Enhancements pop-up menu in the toolbar.

  4. To open the Video inspector, choose Window > Show Inspector (or press Command-4).

  5. In the Effects section of the Video inspector, move the pointer over the effect name and click the Apply Effect Masks button .

    Effects section of the Video inspector showing
  6. In the pop-up menu that appears, choose Add Shape Mask.

    The onscreen controls appear in the Viewer, superimposed over the video image. By default, the shape mask is set to a partially feathered circle in the center of the frame. The Shape Mask parameter appears in the effect’s section of the Video inspector.

  7. Use the onscreen controls to adjust the mask shape.

    Default shape mask and onscreen controls in Viewer
    • To position the shape: Drag the center.

    • To adjust the shape’s width or height: Drag any of the four handles at the 90-degree points (top, bottom, left, or right) of the inner circle. You can hold down the Shift key while dragging to force all sides to scale proportionally.

    • To control the roundness of the shape: Drag the handle to the left of the inner circle’s top handle.

    • To rotate the shape: Drag the rotation handle (extending from the center).

    • To control the softness of the shape’s edge: Drag the outer circle. Setting the outer circle close to the inner circle creates a hard edge and an abrupt visual transition to the effects you apply, and dragging the outer circle away from the inner circle creates a softer edge and a more gradual transition.

    To show or hide the mask’s controls, click the Shape Mask Onscreen Controls button to the right of the shape mask name in the mask list.

    For more information about onscreen controls for shape masks, see Create simple shape masks.

    Note: At any time, you can view the mask alpha channel by clicking View Masks (next to the effect name). The mask’s alpha channel appears in the Viewer. White indicates fully opaque mask areas, black indicates areas outside the mask, and levels of gray indicate transparent mask areas. For more information, see Apply a color mask to a video effect and Combine multiple masks on a video effect.