The Moving Picture Experts Group

Component Download Framework

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MPEG Multimedia Middleware (M3W) Component Download


MPEG doc#: N8691
October 2006
Authors: Johan Muskens & Jean Gelissen (Philips)


1.      Introduction

MPEG, a working group in ISO/IEC, has produced many important international standards (for example: MPEG-1, MPEG-2, MPEG-4, MPEG-7, and MPEG-21). MPEG feels that it is now important to standardize an Application Programming Interface (API) for Multimedia Middleware (M3W) that is based on a defined set of requirements [1]. This API provides a uniform view to a multimedia middleware platform that can be realized by a number of different vendors. The platform specified by M3W supports runtime upgrading and extension as well as component trading.

In order to facilitate (runtime) upgrading and extension it must be possible to transfer new software to a device. Since M3W is a component based middleware this means transferring software components. ISO/IEC 23004 Part 5 [2] – Component Download specifies a download framework. The goal of this realization technology is to enable controlled download of software components to a device. In this context controlled means that before the actual transfer of the component we are able to assess whether the component actually "fits".

The download framework specified in M3W is very flexible. It supports a large number of component transfer scenarios, varying from broadcast scenarios to peer-2-peer scenarios to on demand download from a repository.

2.      Component Download Framework

The goal of the Download framework is to enable controlled transfer of components and support a large number of different download and upload scenarios. The flexibility to support different scenarios is reached by identification of 5 roles that can be deployed in a very flexible way (different deployment for different scenarios). The transfer is controlled because the Download not only focuses on component transfer but also takes into account aspects such as identification / authentication, non repudiation and feasibility checking.

The realization of the download framework contains the following roles, each with their own responsibility:

  • Repository - contains components that can be downloaded.
  • Target - enables receiving components
  • Locator - responsible for locating all the entities (realizations of the roles) that participate in a particular download
  • Decider - assesses the feasibility of a particular download (this can include technical fit, business fit, etc)
  • Initiator - initiates and coordinates the download process

By deploying these roles on different devices we are able to support different scenarios. For example by initiating a component transfer to a single device at the home of a consumer box from a PC in a shop specialized in these devices.

Another example can be where the download framework is used to get components from the broadcast stream. In this case all the roles that are part of the download framework are deployed on the M3W device. The Repository role is responsible for the reception of the components that are part of the broadcast stream. The Repository can cache these components if this is needed.

A large number of different deployment possibilities exist, thus a large number of alternative download scenarios can be supported. All with the comfort of being able to have a decider that makes sure that only the appropriate components will be transferred to a specific device.

3.      Summary

The Application Programming Interface (API) for Multimedia Middleware specified by M3W provides a uniform view to the Multimedia Middleware in a device. In order support upgrading and extension we need the ability to transfer software components to a device and therefore a download framework specification is part of M3W.

The goal of the download framework is flexible and controlled transfer of software components to a device. The specified framework is flexible and supports a large variety of different download through different deployment of the individual roles that are part of the download framework. The decider, one of the roles of the download framework, gives the opportunity to control which components are downloaded and which are not.

4.      References

[1]   The Multimedia Middleware (M3W) requirements are in the annex to the Multimedia Middleware (M3W) Requirements Document Version 2.0 (ISO/IEC JTC1/SC29/WG11 N6981). A Call for Proposals derived from these requirements was issued at the 70th MPEG Meeting in Palma, Mallorca

[2]   ISO/IEC 23004, Information Technology — Multimedia Middleware, The M3W standard.