MultiMedia Magic - Dual Delivery

Dual Delivery

What Do We Mean by "Dual Delivery?"

We use the phrases "dual delivery" and "dual environment" for the strategy of designing the architecture of Director and Flash content so that the same files can be used in both the executable (projector) and browser plug-in (shockwave) environments. This can cut development costs almost in half, as compared to creating the content for each environment separately.

CBT is one application where we have employed this technique successfully. A school computer lab can deliver the product from an intra-net server via a standard web browser, thus requiring no special installation on the many student machines. Students can also progress at home without even needing an Internet connection, by continuing the same content via a CD-ROM.

The programming architecture is the key to making this work. The "manager" object that is "aware" of the navigation framework and interacts with the host environment must be a "black box," encapsulated and separate from the interface, display code and pedagogical logic of any individual Director and/or Flash content file. The latter simply sends requests and data to the former, with no knowledge of how they are processed.

For example, suppose a product requires a student's progress record to be updated each time a lesson is successfully completed. The individual lesson file only needs to know how to format and when to send a "this-lesson-completed" message to the manager object. It is the manager object that must know what to do with it. In the web browser environment, the manager object might post the data over the network to a middle-ware program that updates a server-side database. However, in the executable environment, the same message might be handled by adding the data to a file on the user's floppy disk.

This type of architecture affects every aspect of production, from automation of lesson creation right down to the processing of graphics and other media assets, and thus must be embraced in a whole-hearted manner in order to succeed. That said, the production efficiencies and economies of scale can be extremely beneficial when this is done correctly.