Dedicated Authoring Systems

Dedicated Authoring Systems are designed for a single use and generally for single streams. Designing this type of authoring system is simple, but if it should be capable of combining even two object streams, it becomes complex. The authoring is performed on objects captured by the local video camera and image scanner or an objects stored in some form of multimedia object library. in the case of dedicated authoring systems, users need not to be experts in multimedia or a professional artist. But the dedicated systems should be designed in such a way that it has to provide user interfaces that are extremely intuitive and follow real-wold metaphors. A structured design approach will be useful in isolating the visual and procedural design components.

Timeline Based Authoring

In a Timeline Based Authoring system, objects are placed along a timeline. The timeline can be drawn on the screen in a window in a graphic manner, or it is created using a script in a manner similar to a project plan. But the user must specify resource object and position it in the timeline. On playback the object starts playing at that point in the time scale. In most timeline based approaches, once the multimedia object has been captured in a timeline, it is fixed in location and cannot be manipulated easily. So, a single timeline causes loss of information about the relative time lines for each individual object. Editing a component causes all objects in the time line to be reassigned because the positions of objects are fixed in time, only in sequence. Copying portions of timeline becomes difficult because it is difficult to predict the start of new section. This limitation of using timeline approach can be overcome by defining time relations directly between objects.

Structued Multimedia Authoring

A Structured Multimedia Authoring system consists of two stages:

1. The Construction of the structure of presentation.
   
2. Assignment of detailed timing constraints
   

A successful structured authoring system must provide the following capabilities for navigation though the structure of the presentation.

1. Ability to view the complete structure.
   
2. Maintain a hierarchy of objects.
   
3. Capability to zoom down to any specified component.
   
4. View specific components in part or from start to finish.
   
5. Provide a running status of percentage full of the designated length of the presentation.
   
6. Clearly show the timing relations between the various components.
7. Ability to address all multimedia types, including text, image, audio, video and frame based digital images.

The author must ensure that there is a good fit within each object hierarchy level. The navigation design of authoring system should allow the author to view the overall structure while examining a specific object segment more closely. The design of the views must show relevant information for a specific view.