Availability; Running Status

Before doing anything to an object, the MHEG-5 engine must prepare it. Preparing an object typically entails retrieving it from the server, decoding the interchange format and creating the corresponding internal data structures, and making the object available for further processing. The preparation of an object is asynchronous; its completion is signalled by an IsAvailable event.

All objects that are part of an application or a scene have a RunningStatus, which is either true or false. Objects whose RunningStatus is true are said to be running, which means that they perform the behaviour they are programmed for. More concretely:

• only running Visibles are actually visible on the screen,
• only running Audio objects are played out through the loudspeaker,
• only running Links will execute the action part if the associated event occurs, etc.