Resource Demands of Multimedia Applications

  Applications make use of various system resources, which are provided by the different system components. According to Steinmetz [Ste95], a  resource is a system entity that a task requires for the manipulation or presentation of data. Typical resources offered by a multimedia-capable system include for example the CPU, the memory management, the file systems, network access, and special hardware like cameras or sound subsystems.
A resource is categorised as either:

• Active or passive. Active resources provide a service, normally by making use of passive resources.
• Exclusive or shared. Exclusive resources can be used by one task at a time only, whereas shared resources may be used by various tasks concurrently.
• Single or multiple, depending on the number of instances of that particular resource existing in a given system.

The  capacity of a resource is measured by a task's ability to perform its work in a given time span using that resource. To support continuous media, even systems comprising high-capacity networks and fast processors require real-time mechanisms to provide the necessary resources within the time constraints specified by the desired quality and by the type of the processed media.

For distributed multimedia applications, the required communication structure is of great importance. Traditional networking applications like file transfer generate one-to-one traffic, whereas typical multimedia applications such as video conferences or distributed virtual reality games communicate via one-to-many or even many-to-many message paths.

Table on page , taken from [Hus96, p. 17,], compares the demands of some typical application types.

 
Table:  Requirements of different multimedia application classes.