The effect mask feature allows one or more effects to be applied only to a specific region of a clip. Masks can be animated over time, for example, to follow a moving object in a video.

Masks are made up of three or more points, each of which can be animated separately.

Adding, changing and animating effect masking is done in the Effects Window. For information on opening the Effects Window, see Video Effects.

Adding a mask

1. Click the button on the toolbar
2. The mask's shape can be seen in the Clip Preview

Changing a mask's shape

1. Select the mask by clicking on its title bar in the effect window
2. To move an existing point, click and drag it on the Clip Preview
3. To add a new point, click on the line between two points
4. To delete a point, right-click on it

Clearing a mask

1. Click the button on the toolbar
2. The mask is now cleared and all further effects added to the effect chain will apply to the whole clip

Animating a mask

1. Select the mask by clicking on its title bar in the effect window
2. Ensure that the animation editor is shown
3. Click the button to show the animation line on the animation editor
4. Move the red timeline cursor to where a particular mask shape is required
5. Click the button to add a new keyframe if one doesn't already exist at that point
6. Change the shape of the mask
7. Repeat steps 4-6 until all keyframes are set