Part 2 Multimedia Representation Control MediaLisp Interpreter System Demonstration Conclusion

Multimedia Representation Control System & Phase User Selection Automatic Selection Example

System Media lisp maintains a set of system properties. Those properties can be used to configure the behavior of the overall environment for the multimedia presentation. System properties include a basic set of preserved properties and user customnized properties.

System Preserved Properties The set of system properties contain at least : Physical time Interval Error handling policy Supported multimedia types and corresponding media players

System Property Semantics Each entry of system property is “name-value” pair, it can be can be referenced by its unique name (GetSProperty property_name) (SetSProperty property_name property_value …)

Phase Phase provides much detailed control over multimedia presentation. A phase is a sub runtime environment under environment MediaLisp. Similarly, the system can be regarded as an overall phase over the whole multimedia presentation. When a phase is bound to a some specific multimedia objects, MediaLisp will use the properties of the phase specified in the phase instead of the system proterties.

Operations Related to Phase To declare a phase To set the Phase properties To retrieve the Phase properties To bind multimedia objects in the presentation to phase.

Selection The most prominent feature of MATN model is the support of selections. The selection can be classified as: User Selection: In the middle of presentation, the choice needs to by made by user involvement Automatic Selection: The decision is conducted by the specification in the “Condition Table”

Case The semantics of “Case” is designed for user selection, its semantics includes: A prompt (string array) that will be displayed at presentation time for interactively accepting user selections A sequence of multimedia objects correspond to the prompt strings respectively

Select “Select” is used to specify the “Condition Table”. Each entry in the condition table consists of a boolean clause to describe arbitrarily complex condition and the underlying action or the media object. A select clause contains a list of the condition-action pairs. The condition must in the condition table consists of a boolean

Example of User Selection <Script> (setq T1(@ "T1")) (duration "T1" 10) …………... (setq A1 (@ "A1")) (duration "A1" 10) (setq A2 (@ "A2")) (duration "A2" 10) (setq A3 (@ "A3")) (duration "A3" 10) (setq Prompt (Prompt ”Select audoi-1" " Select audoi-2" " Select audoi-3")) (setq C (case Prompt A1 A2 A3 )) (@ "V1") (duration "V1" 30) (present (<< T1 C (? "V1")))

MATN and Running Result of the Example

Multimedia Lisp Interpreter To support multimedia related functionality, MediaLisp must provide: Multi-threaded execution and management support. Network communication ability Real-time management and synchronization. Intelligence to handle the semantic heterogeneity of multimedia representation. The ability to display various multimedia objects via various devices.

Steps Involved in Interpretion To invoke common lisp compiler/interpreter to accomplish syntax and semantic check, process all pure lisp aspects (Arithmetic operation, common variable & clause evaluation). An extra procedure to process all multimedia presentation related semantics to generate a MATM like data structure. This data structure will be used to direct the multimedia presentation.

System Demonstration The following example is used to give a rough outlook of the design idea.

<script> (setq m1 (@ "mm_1" ))(setq m2 (@ "mm_2"))(setq m3 (@ "mm_3")) (setq m11 (@ "m11" ))(setq m12 (@ "m12"))(setq m13 (@ "m13")) (Duration m11 10) (Duration m12 40)(Duration m13 30) (setq m91 (@ "m91" ))(setq m92 (@ "m92"))(setq m93 (@ "m93")) (Duration m91 10)(Duration m92 5)(Duration m93 5) (setq m911 (@ "m81" )) (setq m922 (@ "mm82")) (setq m933 (@ "mm83")) (setq yy (prompt "option #1" "option #2" "option #3" )) (setq cc (case yy (|| m91 m911) (<< m92 m922) (|| m93 m933) )) (setq ww1 (<< m1 m2 m3 cc)) (setq ww2 (|| m11 m12 m13)) (present (<< ww1 ww2))

Parsed MATN

Media Object Property Set

Presentation Simulation

Summary It’s expressive enough to describe arbitrarily complex temporal relationship among multimedia objects in a presentation It provides a practicable way to encode condition tables and user selection. It also provides a concrete evidence to prove that the MATN model is both feasible and practicable.