Ingo Barth

Cinema - An architecture for distributed multimedia applications

Distributed multimedia applications combine the advantage of distributed computing with the capability of processing discrete and continuous media in an integrated fashion. The development of multimedia applications in distributed environments requires specific abstractions and services, which are usually not provided by generic operating systems. These services are typically realized by software components, often referred to as middleware.

A negotiation and resource reservation protocol (NRP) for configurable multimedia applications

Distributed multimedia applications require negotiation of quality of service (QoS) and resource reservation for distributed application parts and communication links. Negotiation of QoS is a balancing process between the QoS specified by a client, the resource availabilities of the distributed system and the functional capabilities of the distributed application. Negotiation requires application level QoS descriptions and an end to end view spanning the whole distributed application. NRP is an application level protocol meeting these requirements. NRP performs negotiation based on client specified QoS value ranges and given resource availability on endsystems and communication links. NRP is independent of application level QoS semantics. It allows QoS negotiation and resource reservation in three phases and supports a wide range of distributed application topologies.

Configuring distributed multimedia applications using CINEMA

We describe the configuration of distributed multimedia applications using the CINEMA system. Components, interconnected by links via ports are used to handle multimedia data. Configuration management controls these interconnections, establishes components in threads on different systems and allows an interactive control of data handling functions. We present an object-oriented interface, that is able to handle different types of components. To demonstrate the flexibility of this approach we explain a generic application of the CINEMA system to do an interactive configuration of applications using a graphical interface.

Extending the Rate-Monotonic Scheduling Algorithm to Get Shorter Delays

A modification for the rate monotonic scheduling algorithm is presented. This modification allows a shorter delay and jitter for a class of tasks. This will result in a shorter end-to-end delay for distributed and pipelined data stream handling. Beside the advantage of the shorter delay and smaller jitter, the disadvantages of the modifications are discussed in quality and quantity. Measurement results of a split-level scheduler using the modified algorithm and a simulation of the algorithm are compared.

Levels of Quality of Service in CINEMA

Distributed multimedia systems require quality of service at various abstraction levels. At the application level, QoS describes communication in terms of application specific processing units, e.g. frames. At the transport level QoS is used to describe the communication load for the transport system. An architecture integrating the various levels is presented. The architecture provides the framework for performing negotiation of QoS and resource reservation. It includes the specification of a programmer interface and a flowspec carrying QoS information between communication nodes.

Implementierung multimedialer Systemdienste in CINEMA

Die Erstellung verteilter Multimedia-Anwendungen setzt leistungsfahige Entwicklungsplattfonnen voraus, innerhalb deren Probleme wie die Ubertragung multimedialer Daten, die Gewahrleistung der Dienstgute durch Reservierung von Ressourcen und die Synchronisation von Datenstromen gelost werden. Cinema (Configurable INtEgrated Multimedia Architecture) bietet als eine solche Entwicklungsplattform Abstraktionen zur Nutzung multimedialer Systemdienste an, womit funktionale Bearbeitungseinheiten erstellt, komplexe Verarbeitungstopologien in verteilten Systemen aufgebaut und unter Einhaltung von Synchronisations- und Dienstgute-Spezifikationen gesteuert werden konnen. In diesem Papier werden nach einem kurzen Uberblick uber die Abstraktionen der Cinema-Dienstschnittstelle die internen Strukturen und Ablaufe vorgestellt, mit denen die Multimedia-Dienste in verteilten Systemen erbracht werden.

Struktur der Kommunikationsprotokolle im GMD-Netz

Im GMD-Netz ist ein rekursives System von Kommunikationsprotokollen auf einer rekursiven Kanalstruktur implementiert. Multiplexen und Demultiplexen von Datenstromen, Blocken und Entblocken, Pufferverwaltung, Fluskontrolle und Error-Recovery sind Bestandteil dieser Protokolle.

Demonstration of the Cinema system

CINEMA (Configurable Integrated Multimedia ArchiThe flow graph is composed of two video source components connected to a picture-in-picture mixing compotecture) [1] is a middleware system providing services for distributed multimedia applications. These services innent, which provides a data stream multicasted to two sink components. Prior to each sink component a filter compoclude configuration management, session management nent is included. and stream control and synchronization functions. For structuring multimedia applications similar concepts are In CINEMA, data streams are typed. For example, the meadopted as in other projects (e.g., see [2]), including IMA dia type of a stream may be “MPEG_encoded_video”,