MPEG-7

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MPEG-7 is a retired in 2002 ISO - standard (ISO / IEC 15938), which by the Moving Picture Experts Group , in short MPEG been defined. MPEG-7 is a short form, the actual name is Multimedia Content Description Interface . The standard is generally used to describe multimedia data using meta information . MPEG-7 metadata is stored in the form of one or more XML documents. In addition to the XML representation of the MPEG-7 data, which is defined by several complex XML schemes, there is also a memory- optimized binary representation, called BiM .

application

Unlike MPEG-1 , MPEG-2 and MPEG-4, MPEG-7 is not a compression standard for video or audio data. It is used to describe different aspects of multimedia data. Among other things, MPEG-7 standardizes metadata for:

  • managing the creation, production and use of content
  • the description of content in structural and semantic terms,
  • the organization of content,
  • user-specific data such as user profiles and
  • Aspects of access to the data such as views and summaries.

The definition of MPEG-7 descriptors and description structures makes it possible to expand MPEG-7 descriptions for the requirements of the respective applications. If the full functionality of MPEG-7 is not required, an MPEG-7 profile (part 9 of the standard) can be used to limit the scope with regard to descriptors and description schemes.

Main components

The MPEG-7 standard essentially defines three elements:

Descriptors

  • Descriptors are used to describe the specific characteristics (features) of the multimedia file to be described. Such features can e.g. B. the color or the title of a scene, but also semantic descriptions of it. In general, descriptors are the representation of a feature, which in turn represents a data segment that is of a certain significance for a user or a system.

Description Schemes

  • Description schemes are predefined descriptor structures that are related to one another, which can also be relations between descriptors and description schemes or the relations of description schemes to one another.

A film can serve as an example, the scenes of which are described in terms of content, but to which technical descriptions (color, luminance, etc.) are related.

Description Definition Language (DDL)

  • The DDL is a language by means of which descriptors and description schemes can be defined and extended. It is an extension of XML Schema .

The definition of MPEG-7 descriptors and description structures makes it possible to expand MPEG-7 descriptions for the requirements of the respective applications. Using this description method, data can be stored and exchanged in a standardized manner in different application fields, such as those used in broadcasting or in multimedia digital libraries.

construction

The MPEG-7 standard is currently organized in 10 parts. This organization should make it possible to use the individual technology fields behind the respective points in isolation, which corresponds to the MPEG toolbox principle . For example, the scope with regard to descriptors and descriptor schemes can be restricted by means of profiles (Part 9) if their full functionality is not required.

  • Systems (describes the storage format of the MPEG-7 documents)
  • Description Definition Language (the DDL describes the syntax of the MPEG-7 description structure)
  • Visual descriptors (capture descriptive features of images and videos)
  • Audio descriptors (specifying audio signals)
  • Multimedia Description Schemes (the MDS specifies a library of description structures)
  • Reference software (contains example implementations for generating and processing MPEG-7 descriptors)
  • Conformity (instructions for fulfilling the conformity conditions, quality control)
  • Extraction and use of descriptors (instructions for handling content-based descriptors)
  • Profiles (simplification in use by restricting the scope of the description)
  • Schema definitions (collects the XML schemas used)

MPEG-7 software / demonstrators

  • Caliph & Emir : Creation and search of MPEG-7 documents for image files.
  • IBM VideoAnnEx Annotation Tool : Creation of MPEG-7 documents for video files. Features: Automatic segmentation, manual keywording of segments (binary release, proprietary license)
  • MPEG-7 Audio Encoder : Creation of MPEG-7 documents for audio files based on automatic extraction of low-level metadata, no user interface (Binary & Source Release, Java , LGPL )
  • XM Feature Extraction Web Service : The functionalities of the eXperimentation Model are exposed as web services in order to be able to automatically extract low-level MPEG-7 visual descriptions from images. (PDF; 811 kB)
  • TU Berlin MPEG-7 Audio Analyzer (web demo): MPEG-7 documents (XML) are created for audio files (WAV, MP3). All 17 MPEG-7 low-level audio descriptors are implemented.
  • TU-Berlin-MPEG-7-Spoken-Content-Demonstrator (web demo): Creates MPEG-7 documents (XML) with the SpokenContent descriptor from a speech signal (WAV, MP3).
  • MP7JRS C ++ Library Complete MPEG-7 implementation of Part 3, 4 and 5 (Visual, Audio and MDS) of the Joanneum Research - Institute for Information and Communication Technologies, Audiovisual Media Group.

literature

  • BS Manjunath (Ed.), Philippe Salembier (Ed.), Thomas Sikora (Ed.): Introduction to MPEG-7: Multimedia Content Description Interface . Wiley & Sons, April 2002 - ISBN 0-471-48678-7
  • Harald Kosch: Distributed Multimedia Database Technologies . CRC Press, January 2004 - ISBN 0-849318-54-8
  • Giorgos Stamou (Ed.), Stefanos Kollias (Ed.): Multimedia Content and the Semantic Web: Standards, Methods and Tools . Wiley & Sons, May 2005 - ISBN 0-470-85753-6
  • Hyoung-Gook Kim, Nicolas Moreau, Thomas Sikora: MPEG-7 Audio and Beyond: Audio Content Indexing and Retrieval . Wiley & Sons, October 2005 - ISBN 0-470-09334-X

Web links