MPEG-21 Digital Item Adaptation

Abstract

Definition: MPEG-21 Digital Item Adaptation (DIA) enables interoperable access to (distributed) advanced multimedia content by shielding users from network and terminal installation, management, and implementation issues. Context and ObjectivesUniversal Multimedia Access (UMA) [1] refers to the ability to seamlessly access multimedia content from anywhere, anytime, and with any device. Due to the heterogeneity of terminals and networks and the existence of various coding formats, the adaptation of the multimedia content may be required in order to suit the needs and requirements of the consuming user and his/her environment. For enabling interoperability among different vendors, Part 7 of the MPEG-21 Multimedia Framework [2], referred to as Digital Item Adaptation (DIA) [3], specifies description formats (also known as tools) to assist with the adaptation of Digital Items. Digital Items are defined as structured digital objects, including standard representation, identification and metadata, and are the fundamental units of distribution and transaction within the MPEG-21 framework. The concept of MPEG-21 DIA is illustrated in Figure 1. As shown in this figure, only tools used to guide the adaptation engine are specified by the standard. The adaptation engines themselves are left open to various implementations. However, description formats and format-independent mechanisms that provide support for the adaptation in terms of media resource adaptation, description adaptation, and/or Quality of Service (QoS) management are within the scope of the standardization, and are collectively referred to in Figure 1 as DIA tools.

Introducing a unified framework for content object description

“…The MPEG-21 Digital Adaptation tries to tackle the issue of accessing media "any time and anywhere" [Timmerer 2008]. This implies the adaptability of Digital Items and their resources to different devices, networks etc.…”