A variety of systems are used for authoring multimedia presentations such as motion pictures, television shows, advertisements for television, presentations on digital versatile disks (DVDs), interactive hypermedia, and other presentations. Such authoring systems generally provide a user interface and a process through which multimedia data is captured and stored, and through which the multimedia presentation is created, reviewed and published for distribution. The user interface and process for authoring generally depend on the kind of presentation being created and what the system developer believes is intuitive and enables an author to work creatively, flexibly and quickly.
Some multimedia presentations are primarily nontemporal presentations. That is, any change in the presentation typically depends on user activity or other event, instead of the passage of time. Some nontemporal multimedia presentations may include temporal components. For example, a user may cause a video to be displayed that is related to a text document by selecting a hyperlink to the video in the document.
Other multimedia presentations are primarily temporal presentations incorporating audio and/or video material, and optionally other media related to the temporal media. Primarily temporal media presentations that are well known today include streaming media formats such as QuickTime, Real Media, Windows Media Technology and SMIL, and formats that encode data in the vertical blanking interval of a television signal, such as used by WebTV, ATVEF, and other similar formats.
A variety of authoring tools have been developed for different kinds of presentations. Tools for processing combined temporal and nontemporal media include those described in PCT Publication No. WO99/52045, corresponding to U.S. patent application Ser. No. 09/054,861, and PCT Publication No. WO96/31829, corresponding to U.S. patent application Ser. No. 08/417,974, and U.S. Pat. No. 5,659,793 and U.S. Pat. No. 5,428,731.