You used the Convert Vertex tool to change a corner vertex to a smooth point with Bezier handles, but you could have created a Bezier mask in the first place. To do so, click in the Composition panel with the Pen tool where you want to place the first vertex. Then click where you want to place the next vertex, and drag in the direction you want to create a curve. When you are satisfied with the curve, release the mouse button. Continue to add points until you’ve created the shape you want. Close the mask by either clicking on the first vertex or double-clicking the last vertex. Then switch to the Selection tool to refine the mask.
Feathering the edges of a mask
The mask looks good, but the edge of the screen looks a little too sharp and unrealistic. To address this, you’ll feather, or soften, the edges.
- Select the TabletVideo.mov layer in the Timeline panel, and press the F key to display the Mask Feather property for the mask.
- Increase the Mask Feather amount to 3.0, 3.0 pixels.

- Hide the properties for the TabletVideo.mov layer, and then choose File > Save to save your work.
Replacing the content of the mask
You are now ready to replace the background with the video of a sea turtle and blend it with the overall shot.
Tip
In effects that reference layers, you can use masks for greater control over the effect’s influence. You can also use expressions to animate mask points.
- In the Project panel, select the SeaTurtle.mov file and drag it to the Timeline panel, placing it below the TabletVideo.mov layer.

- Choose Fit Up To 100% from the Magnification Ratio pop-up menu at the bottom of the Composition panel so that you can see the whole composition.
Note
If you’re using a Mac with Retina display, you’ll see Fit Up To 200%. - Select the Selection tool ( ), and then drag the SeaTurtle.mov layer in the Composition panel slightly to the left, centering it in the tablet screen.
- Go to 2:07. In the Timeline panel, drag the entire SeaTurtle.mov layer to the right so that it begins at 2:07 and ends at the same time as the TabletVideo.mov layer.

Zooming and panning by touch
If you’re using a touch-enabled device, such as a Microsoft Surface, Wacom Cintiq Touch, or multi-touch trackpad, you can use your fingers to zoom and pan. Touch gestures let you zoom and pan in the Composition, Layer, Footage, and Timeline panels.
To zoom: Pinch two fingers closer together to zoom in, or move them further apart to zoom out.
To pan: Move two fingers in unison to pan up, down, left, or right in the panel’s current view.