Æliens

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networked multimedia

• real-time transmission of continuous media information (audio, video)
• substantial volumes of data (despite compression)
• distribution-oriented -- e.g. audio/video broadcast

network criteria

• throughput -- bitrates, burstiness
• transmission delay -- including signal propagation time
• delay variation -- jitter
• error rate -- data alteration, loss

• multicasting and broadcasting capabilities
• document caching

Quality of Service

Quality of Service is a concept based on the statement that not all applications need the same performance from the network over which they run. Thus, applications may indicate their specific requirements to the network, before they actually start transmitting information data.

QoS requirements

• hard requirements
• guidance for optimizing internal resources
• criteria for acceptance

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virtual objects

where

• $C\_1,...,C\_k$ -- mutually exclusive conditions
• $Q\_1,...,Q\_k$ -- queries
• $O\_1,...,O\_k$ -- objects

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networked virtual environments

• shared sense of space -- room, building, terrain
• shared sense of presence -- avatar (body and motion)
• shared sense of time -- real-time interaction and behavior

• a way to communicate -- by gesture, voice or text
• a way to share ... -- interaction through objects

challenges

• network bandwidth -- limited resource
• heterogeneity -- multiple platforms
• distributed interaction -- network delays
• resource management -- real-time interaction and shared objects
• failure management -- stop, ..., degradation
• scalability -- wrt. number of participants

manage dynamic shared state

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• the Java Media Framework, and
• the DLP+X3D platform

java Media Framework

The JavaTM Media APIs meet the increasing demand for multimedia in the enterprise by providing a unified, non-proprietary, platform-neutral solution. This set of APIs supports the integration of audio and video clips, animated presentations, 2D fonts, graphics, and images, as well as speech input/output and 3D models. By providing standard players and integrating these supporting technologies, the Java Media APIs enable developers to produce and distribute compelling, media-rich content.