1. A computer implemented authoring system for authoring a presentation of temporal media and nontemporal media, comprising: a graphical user interface for enabling a user to interactively author the presentation using a timeline comprising one or more tracks for temporal media and nontemporal media; data defining a spatial relationship among the temporal and nontemporal media in a display area, wherein the data indicates, for each track of the temporal media and for the nontemporal media a portion of the display area in which media from the track will be displayed and a portion of the display area in which the nontemporal media will be displayed; wherein the graphical user interface also enables the user to modify the data defining the spatial relationship by presenting to the user, for each portion of the display area, the tracks available for the portion of the display area, and receiving from the user an indication of a track selected by the user for each portion of the display area; and a viewer having access to the timeline and the data defining the spatial relationship, and having an output providing display information for displaying the temporal media and the nontemporal media combined according to the timeline and the spatial relationship, for each of one or more specified times along the timeline.
1. A computer implemented authoring system for authoring a presentation of temporal media and nontemporal media, comprising: a graphical user interface for enabling a user to interactively author the presentation using a timeline comprising one or more tracks for temporal media and nontemporal media; data defining a spatial relationship among the temporal and nontemporal media in a display area, wherein the data indicates, for each track of the temporal media and for the nontemporal media a portion of the display area in which media from the track will be displayed and a portion of the display area in which the nontemporal media will be displayed; wherein the graphical user interface also enables the user to modify the data defining the spatial relationship by presenting to the user, for each portion of the display area, the tracks available for the portion of the display area, and receiving from the user an indication of a track selected by the user for each portion of the display area; and a viewer having access to the timeline and the data defining the spatial relationship, and having an output providing display information for displaying the temporal media and the nontemporal media combined according to the timeline and the spatial relationship, for each of one or more specified times along the timeline. 2. The authoring system of claim 1 , wherein the graphical user interface enabling the user to modify the data defining the spatial relationship includes a plurality of menus, including a menu for each portion of the display area, wherein each menu lists available tracks for selection for association with the corresponding portion of the display area.