MPEG7

MPEG-7, formally ISO/IEC 15938, the Multimedia Content Description Interface, is a standard within the MPEG family that provides a comprehensive framework for describing multimedia content. It is designed to support content-based search, indexing, retrieval, and interoperability across different systems, independent of how media are encoded.

The core concept of MPEG-7 is a modular set of Description Schemes (DS) and Description Definition Languages (DDL). Descriptors are defined in an XML-based format, using an MPEG-7 schema to describe both low-level features and high-level content. This structure allows the combination of multiple DSs to characterize a media item in a flexible, machine-readable way.

Descriptors typically cover visual attributes such as color, texture, shape, and motion; audio attributes including timbre and rhythm; and higher-level descriptions like structure and semantics. The standard is designed to be extensible, enabling new DSs to be added as technology and applications evolve.

MPEG-7 is not a video or audio coding standard; it does not specify how media should be compressed or decoded. Instead, it provides metadata that describes the content, which can be used for search, asset management, and cross-system interoperability. It is a framework published by ISO/IEC in the MPEG-7 family, with multiple parts and ongoing revisions.

Adoption of MPEG-7 has varied, with some applications implementing subsets of DSs or relying on external tools for feature extraction. The standard remains influential as a conceptual model for describing multimedia content and enabling interoperability in metadata workflows.