16. The system of claim 14 , the compose window further including an interpolation control by which a user identifies a content asset for interpolation that appears in a first and second non-consecutive visual displays with the content asset for interpolation having different modifications for the first and second visual displays and results in the modifications for the content asset for interpolation to be defined in the presentation instructions for the visual display occurring sequentially between the first and second visual displays according to a combination of the different modifications for the identified content assets.
14. A system for editing a multimedia presentation that includes plurality of scenes, each scene including a sequence of visual displays, the multimedia presentation being defined by a presentation script such as a presentation script including instructions that include identification of a plurality of content assets, identification of one or more visual displays in which the identified content assets are to be included, one or more modifications of the content assets to be performed prior to inclusion of the identified content assets in the one or more visual displays, instructions for positioning the modified content assets in the one or more visual displays, and layering instructions for determining, for a portion of the visual display that includes plurality of modified content assets, the forward and backward relation of the plurality of modified assets to each other in the visual display, the system comprising: a processor configured to implement a user interface for editing a presentation script defining a multimedia presentation, the user interface comprising: a timeline strip for indicating a display order for individual scenes in a presentation; and a compose window coupled to the timeline strip for editing individual scenes in a presentation and individual content assets within the individual scenes, resulting in corresponding edits being made to the presentation script by the processor.