Introduction to MPEG Moving Pictures Experts Group, Geneva based working group under the ISO/IEC standards. In charge of developing standards for compression, decompression, processing & coded representation of audiovisual information.
MPEG -1 MPEG-1( ) Goal: coding of moving picture with associated audio at rate up to 1.5Mbps Entertainment and storage. VHS quality. Video CD is full application of MPEG-1 -3 layers in audio coding. -Audio Layer 3 is the famous MP3
MPEG-2 MPEG-2( ) Higher bit rate at 80Mbps mainly broadcast Application in DVD, HDTV etc. Backward compatibility with MPEG-1
MPEG-4 MPEG-4 embraces several areas: Coding of visual objects Coding of audio objects Scene description and user interaction Most important: object coding Used for video transmission in the internet. Bit rate ranges from kbps to Mbps
Overview MPEG-1 and MPEG-2 are data compression MPEG-4 is the start towards data description (object coding). MPEG-7 is data description Move from merely data compression to data description
Compression? Compression is the process of reducing the size of a file by encoding its data information more efficiently. the result is a reduction in the number of bits and bytes used to store the information. a smaller file size is generated in order to achieve a faster transmission of electronic files and a smaller space required for its downloading. 2types –lossy & lossless Video- lossy compression
What is MPEG 7 A standard for describing features of multimedia content. Provides a rich set of tools for completely describing multimedia content.
Features International standard ISO/IEC Formally known as ˝Multimedia Content Description Interface˝ It gives ‘information’ about ‘information’. It describes metadata
Objectives Provides fast & efficient searching filtering & content identification method. Index a big range of applications Audiovisual information that mpeg -7 deals with are audio, video, images, graphs & 3D models
MPEG-7 Elements Descriptors (D): define the syntax and semantics for the representation of features. Description Schemes (DS): specify the structure and semantics of the relationships between their components.
Contd… Description Definition Language (DDL): the language allowing the creation of new DSs and the extension of existing DSs. based on XML Schema. Systems tools: support coding, multiplexing and synchronization of descriptions.
MPEG-7 Structure Descriptor (D) Description Schemes (DSs) Description Definition Language (DDL)
Scope Of MPEG 7 Description Production (extraction) Standard Description Consumption
MPEG-7: Major Functionalities Systems (ISO / IEC ) Description Definition Language (ISO / IEC ) Visual (ISO / IEC ) Audio (ISO / IEC ) Multimedia Description Schemes (ISO / IEC ) Reference Software (ISO / IEC )
MPEG 7 : Systems It defines tools to: provide for efficient storage and transport. synchronize between content and manage and protect intellectual property description.
Audio descriptors High-Level Audio Description Tools (Ds & DSs) o Instrumental timbre description tools o Sound recognition tools o Spoken content description tools Melody description tools (facilitate query-by-humming) Generic Audio Description tools. o Based on low level descriptors such as timbral temporal, basic spectral, basic, timbral spectral, spectral basic, fundamental frequency & harmonics description.
Visual Descriptors Color Descriptors Texture Descriptors Shape Descriptors Motion Descriptors for Video
Conclusion MPEG-7 provides a comprehensive and flexible framework for describing the content of multimedia. To describe content implies knowledge of elements it consists of, as well as, knowledge of interrelations between those elements. The most important application is multimedia management, where such knowledge is prerequisite for efficiency and accuracy.
Applications Digital libraries, Education Multimedia editing Cultural services Multimedia directory services Broadcast media selection Journalism E-Commerce Surveillance Investigation services