You can use the matte cleaner to refine the results of a keying effect. The matte, which defines the transparent areas created by the key, can be modified with these controls to improve the results.
- Smooth: Makes the edge of the matte smoother. Any corners or abrupt changes in direction of the matte edge are rounded, using the radius (in pixels) which you specify.
- Feather: Makes the edge of the key softer. A gradient of transparency is applied to the edge of the matte, to a width (in pixels), which you specify.
- Choke: Shrinks the edge of the key. This value sets the distance, in pixels, by which the edge of the white area will be moved inward, reducing the white area of the matte.
- View Matte: Enable this option to view the transparency matte as a greyscale image. Disable it to view the original image with the transparency applied.