User`s guide

The Timeline Window
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To switch between the shape and face tracks, use the Track Selector button in the Controls
window. See “Controls Window Buttons” on page 90.
Compositing on the Timeline
Compositing is the layering of images to produce one new integrated image. You can create
and add an unlimited number of tracks on the timeline. The result of the layering or
compositing of the tracks is displayed on the Composite window. Remember that the
overlaying clip must have an alpha channel for the composite to be displayed.
On the timeline, the media is composited from the bottom to the top. The bottom-most track
is known as the background track. You can use video from an Avid editing system as a
backdrop for your effect. Unlike the other shape tracks, you cannot animate or transform
background tracks in any way, nor can you filter or rename them. For this reason,
background tracks have no shape control tabs.
Nested tracks