MMDB-9 J. Teuhola 2012 1

9. Standardization: MPEG-7

“Multimedia Content Description Interface” Standard for describing multimedia content (metadata). Goal: Efficient searching, browsing and filtering of audiovisual

material: still images, graphics, 3D models, audio, speech, video, multimedia presentations.

Feature extraction and the search engine are not included inthe standard.

Descriptions are based on XML. Overview: http://www.chiariglione.org/mpeg/standards/mpeg-7/mpeg-7.htm

Featureextraction

Standarddescription

Searchengine

Scope of MPEG-7

MMDB-9 J. Teuhola 2012 2

MPEG-7 concepts

Feature: Distinctive characteristic of a given MM object Descriptor: Defines the syntax and semantics of feature

representation; instantiation = descriptor value Description scheme: Structure and semantics between components

(which can be descriptors or description schemes) Description definition language (DDL): Allows the creation of new

descriptors and description schemes Description instance: Description scheme + set of descriptor values

that describe the data. Descriptions have coded representations.

Description Definition Language

Descriptors Descriptionschemes

Descriptions

Definition

structuring instantiation

Definition Tags

MMDB-9 J. Teuhola 2012 3

MPEG-7: example descriptors

Visual: Basic structures and layout (2D, 3D, time) Color (color space, dominant color, quantization, layout, …) Texture (edge histogram, homogenous texture, …) Shape (region-based shape, contour-based shape, …) Motion (camera motion, motion activity, motion trajectory,

…) Localization (region locator, spatio-temporal locator) Face recognition

Audio: Basic (low-level) features of audio signals (spectrum etc.) High-level description tools, e.g. sound recognition and

indexing, instrumental timbre, spoken content, audio signature, melodic description

MMDB-9 J. Teuhola 2012 4

MPEG-7: potential application areas

Digital libraries (retrieval from archives of text, images, speech); Education (finding teaching material, preparing virtual courses) Journalism (searching archives by voice, face, etc.) Broadcast indusry (audiovisual archives) Entertainment business (video-on-demand, games) Culture (contents of museums, art galleries); Police investigations (surveillance, face recognition) Geographical information systems (spatial databases, cartography,

natural resources management) Medicine (patient information; telemedicine)