Represents an assets which is associated to a timeline track. It is tied to
the assets by means of an unique ID. Moreover, an element has a duration,
which can override the asset's intrinsic duration and an offset from the
previous element on the timeline track, or from the beginning of the track
if it is the first element.
Represents an assets which is associated to a timeline track. It is tied to the assets by means of an unique ID. Moreover, an element has a duration, which can override the asset's intrinsic duration and an offset from the previous element on the timeline track, or from the beginning of the track if it is the first element.