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Technical University of Crete Department of Electronic and Computer Engineering. Multimedia Data Management Euripides G.M. Petrakis http://www.intelligence.tuc.gr/~petrakis http://courses.ced.tuc.gr Chania 2010. Definition.

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technical university of crete department of electronic and computer engineering

Technical University of CreteDepartment of Electronic and Computer Engineering

Multimedia Data Management

Euripides G.M. Petrakis

http://www.intelligence.tuc.gr/~petrakis

http://courses.ced.tuc.gr

Chania 2010

Introduction

definition
Definition
  • Multimedia: composite entities combining text, audio, images, video (bit-stream objects), graphics
  • Multimedia Information Systems: database systems that support all multimedia data types and handle very large volumes of information

Introduction

slide3
TEXT
  • The most common type of information
  • The least space intensive data type
  • The form in which text is stored varies (plain ascii, word files, spreadsheets, annotations, database fields etc.)
  • Text fonts are becoming complex allowing special effects (color, shade, fill etc.)

Introduction

audio
AUDIO
  • Space intensive (one minute can take up Mbytes), presented as analog, digital or MIDI
  • Analog waveform: electrical signal,
    • amplitude specifies the loudness of the sound
    • in microphones, tapes, records, amplifiers, speakers
  • Digital waveform audio: digital,
    • less sensitivity to noise and distortion
    • involves larger processing and storage capacities
    • Digital Audio Tape (DAT), Compact discs (CD)
    • WAV (Microsoft’s wave file format)

Introduction

midi musical instrument digital interface
MIDI (Musical Instrument Digital Interface)

Furht et.al.96

  • Commands that describe how the music should be played are stored (instead of sound)
  • A music synthesizer generates sound
  • Provides high data compression,
  • Widely accepted

Introduction

images
IMAGES
  • Digital images: sequences of pixels
  • Pixels: numbers interpreted to display intensity, color, contrast etc
    • Binary (0-1 values), gray-scale (8 bits/pixel), colour (3x8 values for RGB)
  • Space overhead depends on image type, resolution, compression scheme
  • Image formats: tiff, bmb, jpeg etc.

Introduction

image concepts and structures
Image Concepts and Structures
  • Binary images: 1 bit/pixel
    • black & white photos, facsimile images
  • Computer Graphics: 4 bits/pixel
  • Grayscale images: 8 bits/sample
  • Color images: 16, 24 bits/pixel

Introduction

rgb representation
RGB Representation
  • A color is produced by adding
    • red, green and blue
  • The straight line R=G=B specifies gray values ranging from black to white

Introduction

yuv representation
YUV Representation
  • YUV describes the luminance and chrominance components of an image
    • 1 luminance: gray scale version of an image
      • Y = 0.299R + 0.587G + 0.114B
    • 2 chrominance components:
      • U = 0.564(B - Y)
      • V = 0.713(R - Y)

Introduction

conversions
Conversions
  • Conversion between RGB and YUV requires multiplication operations
    • an approximation:
    • Y = R/4 + G/2 +B/2, U=(B-Y)/2, V=(R-Y)/2
    • R = Y + 2V, G = Y – (U + V), B = Y + 2U
  • YCbCr is another color format
    • for compression
    • Cb = U/2 + 0.5, Cr = V/1.6 + 0.5

Introduction

video
VIDEO
  • The most space intensive data type
  • A sequence of frames
  • Realistic video playback, transmission, compression/decompression require transfer rates about 30frames/sec
  • Microsoft’s AVI and Apple’s Quicktime file formats integrate video and audio in the same presentation

Introduction

audio video modes of operation
Audio-video Modes of Operation

Furht et.al.96

  • Can be either stored or used / transmitted live in real-time
  • Can be used interactively or non-interactively

Introduction

graphics
GRAPHICS
  • Objects described through their basic elements (e.g., 2D, 3D shapes)
    • these elements can have different sizes, position, orientation, surface, fill etc.
    • compact representations
    • generated and can be manipulated by design tools (e.g., CAD tools)
    • Their descriptions are stored in files

Introduction

2d and 3d graphics objects
2D and 3D graphics objects

Khoshafian

Baker 96

Introduction

multimedia objects
MULTIMEDIA objects
  • Text, audio, images, video, graphics are elements of complex multimedia objects
  • Various tools or applications integrate, process and combine multimedia
  • Applications: multimedia authoring applications that output documents and databases and end-user applications (e.g., video on demand)
  • Tools: for viewing, updating, querying (presentation viewers, browsers etc.)

Introduction

multimedia databases mdb
Multimedia Databases (MDB)
  • Means stored information or database management systems (dbms)
  • Multimedia dbms (mdbms) integrate conventional database capabilities together with different technologies such as Hierarchical storage management (HSM) and Information retrieval (IR)

Introduction

multimedia technologies
Multimedia Technologies
  • Technologies integrated within a mdbms
  • HSM support
  • IR support (exact and approximate)
  • Spatial data types and queries
  • Interactive querying, relevance feedback, refining
  • Automatic feature extraction
  • Automatic content retrieval and indexing
  • Query optimization

Introduction

database capabilities
Database capabilities
  • Persistence: object persist through invocations
  • Transactions: content is inserted, deleted, updated
  • Concurrency control: transactions run concurrently
  • Recovery: failed transactions are not propagated to the db
  • Querying: content can be retrieved
  • Versioning: access previous states of objects
  • Integrity: transactions guarantee consistency of content
  • Security: constraints for accessing/updating objects
  • Performance: optimal data structures and programs

Introduction

hierarchical storage management hsm
Hierarchical Storage Management (HSM)
  • Support storage of multimedia objects
    • On-line: on RAM, magnetic disk
    • Near-on-line: on optical storage
    • Off-line: on tapes, shelves
  • Each level has different
    • Performance: decreases from top to bottom
    • Capacity: increases from top to bottom
    • Cost: decreases from top to bottom

Introduction

information retrieval ir capabilities
Information Retrieval (IR) Capabilities
  • Retrieval is the most common operation
    • Deletions and updates are less common
    • Exact match: search based on exact information
    • Inexact: search based on inexact information e.g.,partial, neighborhood search, can be fuzzy or probabilistic
  • The results are ranked by order of relevance to the query
  • Query refinement
    • Iterate over query results
    • Adjust weights of query terms or features
    • And finally resubmit queries

Introduction

mdbms architecture
MDBMS architecture

Khoshafian

Baker 96

Introduction

mdbms implementation
MDBMS Implementation
  • Relies on 3rd party vendors for each component
    • Relational dbms for typical records
    • separate optical storage module for text/audio/graphics/images/video
    • Text retrieval system (e.g. Lucene)
    • Audio/image/video retrieval system
    • Feature extraction system
    • Multimedia object interface system

Introduction

object oriented multimedia databases
Object-Oriented Multimedia Databases
  • Better design, better suited for multimedia applications
    • Uniform handling of data and operations
    • Data types are objects with internal structures and operations that capture the behavior of objects (e.g., audio playback, video browsing)
  • OO dbms does not satisfy all MM requirements
    • Provides primitives for object handling
    • Multimedia components need to be implemented or integrated

Introduction

multimedia applications
Multimedia Applications
  • Multimedia Systems suggest a variety of applications
    • Multimedia conferencing
    • Multimedia on demand (interactive TV, news on demand)
    • See next page for more …

Introduction

multimedia applications1
Multimedia Applications

Furht et.al.96

Introduction

multimedia conferencing mc
Multimedia Conferencing (MC)
  • Multimedia conferencing enable a number of participants to exchange multimedia information
    • Each participant has a workstation linked to other workstations over high-speed networks
    • Each participant can send or receive mm data and perform certain collaborative activities

Introduction

a video conference system
A video conference system

Furht et.al.96

  • The biggest performance challenge occurs when the participants transmit voice and video
    • These are mixed together to form a composite stream consisting of video and voice streams

Introduction

software architecture
Software Architecture

Furht et.al.96

Introduction

architectures
Architectures
  • Fully distributed: direct connections between the participants
    • Processing and mixing of media at every location
    • Shortest delay
    • The connections increase rapidly
  • Centralized (star) network: a central is connected to every participant
    • Processing and mixing at central node
    • The central node waits until all media is received before mixing and broadcasting

Introduction

architectures cont
Architectures (cont.)
  • Double star network: a central node from one star network is connected to another central node of another star network
  • Hierarchical network: intermediate nodes, root and leaves (participants) connected hierarchically
    • intermediate nodes perform mixing and processing
    • the completely mixed data is sent to root who broadcasts directly to the leaves
    • reduces network traffic significantly

Introduction

video on demand vod
Video on Demand (VoD)
  • Fast networks coupled with powerful computers and compression techniques will be capable of delivering stream data in real-time
  • On-demand multimedia services
    • interactive entertainment
    • video news distribution
    • video rental services
    • digital multimedia libraries

Introduction

interactive television itv
Interactive Television (ITV)
  • An ITV system must be capable of providing
    • basic TV
    • subscription TV
    • pay per view
    • video on demand
    • shopping
    • education
    • electronic newspaper
    • financial transactions
    • single-user and multi-user games

Introduction

this course
This Course
  • Emphasis on
    • Text, images, video
    • Information retrieval & systems
    • Data organization
    • Web information systems
    • Semantic Web
    • Video & MPEG standards
  • No emphasis on
    • Architectures
    • Specific applications (VoD, ITV,MC)
    • Services

Introduction