Standardizing hypermedia information objects

The level of complexity that should be addressed by a standard for the interchange of multimedia and hypermedia information, leading to a layered structure which separates a generic object layer from upper layers dealing with specific applications and from lower layers dealing with operating systems and file formats is discussed. The presentation and encoding of such multimedia and hypermedia information objects for the special needs of real-time, interactive, and communicating applications is the purpose of an International Organization for Standardization/Interexchange Carrier (SIO/IEC) group, known as Multimedia and Hypermedia Information Coding Expert Group (MHEG), the work of which is presented. The scope of the MHEG standard is explained, and an overview of the hierarchy of objects classes is provided, followed by a description of the methodology and coding principles developed in MHEG. The authors describe several categories of multimedia synchronization, making use of spatial and temporal relations between component objects, and relying on a scriptlike structure for more demanding situations.<>