Summary of Research: Automating the Organization of Presentations for Playout Management in Multimedia Databases
 

Multimedia presentation refers to the concurrent presentation of multimedia data using monitors for text, video or still images, and speakers for audio. Each presentation contains multimedia segments retrieved from a database, and is constructed and played out by a presentation manager software.  A presentation could potentially use multiple resources - say 4 PC screens and a set of speakers.

Users express a presentation query by specifying

• inclusion and exclusion constraints of desired multimedia segments for the presentation
• presentation organization constraints for deciding the playout order
• playout control constraints to provide dynamic playout control by the user
• physical playout constraints to insure jitter-free playback of multimedia data

• Inclusion and exclusion constraints are used are utilized for organizing the multimedia segments into a presentation which decides the playout order of the extracted multimedia segments.  A presentation graph is created to represent the presentation satisfying all of the constraints.

• The playout order of the segment is represented in a presentation graph.  If the requested set of organization requirements are not sufficient to create a unique presentation graph, two heuristic methods in the paper are proposed for use to create a unique presentation graph.  Heuristics are used because the problem boils down to the "bin packing problem" which is NP-complete.

Heuristic 1: Maximize Parallelism

Attempt to find the shortest length presentation that satisfies all of the organizational constraints as well as user specified constraints on presentation "width" and "height".
 

Heuristic 2: Steady Flow

Attempt to find the lowest height presentation that satisfies all of the organizational contraints.

Presentation Playout

After a presentation is assembled that satisfies all of the given constraints, dynamic playout control issues are discussed.

Characteristics of a Playout Agent - Schedulable (a lightweight thread of execution)

• Arrival Time

• Earliest start time

• Actual Start time

• Playout Duration

• Deadline

• Actual Finish Time

• Synchronization Primitives

The Playout Agent allows user controls to be applied during playout - pausing and continuing, closing windows, etc.

Much more in depth - See References for more details