Distributed Multimedia Database Systems

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					Distributed Multimedia
Database Systems
   Introduction to Multimedia Database
    Systems
   Introduction to MPEG-7
   Introduction to MPEG-21
   Distributed Multimedia Database
    System
Outline
   Architectural Consideration
   Video Servers and Streaming
   Multimedia Communication
   Client-Design Issues
   Content Adaptation
   Summary
   Architectural Consideration
   Video Servers and Streaming
   Multimedia Communication
   Client-Design Issues
   Content Adaptation
   Summary
Architectural Consideration
   C-S System
   Peer-to-Peer System
   MPEG-21-Based Architecture
Client-Server System
   Client-Server Architecture
       Client applications request multimedia data
        from the server, which are then processed
        locally.
       Drawback - Not scale well with respect to
            the number of users
            the heterogeneity of the terminals employed
            the size of the data requested
   C-S-based multimedia system with different
    profiles
Peer-to-Peer System
   P2P System
       Portable devices with various capabilities send and transfer
        multimedia content from one device to another in order to
        allow greater flexibility
   Peer-to-peer services may have functions
       To hold the content from the creation to the delivery
       To check the capability of the other peer party and see
        whether it can process the multimedia data before delivering
       To create metadata to describe content received from the
        users
   Technical challenges
       The realization of generic information communication
        between peers
        : P2P communication protocols (e.g. CC-PP, JXTA v1.0)
       The protocol considerations communication paradigm has to
        be reconsidered
        : Mobile Agent
MPEG-21-Based Architecture
   Web-based distributed MMDBMS relying on
    MPEG-21
       Multimedia Database holds a collection of MPEG21
        DIs.
       Web server is the front end for all users to the
        framework providers.
       MPEG-21 terminals are where users consume and
        create DIs for the use in the distributed system
   P2P-based multimedia system relying on MPEG-21
   Architectural Consideration
   Video Servers and Streaming
   Multimedia Communication
   Client-Design Issues
   Content Adaptation
   Summary
Video Servers and Streaming
   Stored multimedia data
       Noncontinuous media: text, image
       Continuous media: audio, video
   Video Server (e.g. VOD) can support
       Many concurrent clients
       The ability to scale in terms of clients
       User interactions such as rewind, fast forward,
        pause, and so forth
   Issues in Video server
       Striping Policy
       Load Balancing
       Admission Control
       Disk Scheduling Strategy
       Server, Proxy, and Client Caching
       Presentation Management
       Adaptive Continuous Multimedia Streaming
   Example Video Server: Tiger by Microsoft
       Parallel, fault-tolerant, scalable, and real-time
       Controller – to serve as query interface to the client and
        to perform the admission control
       Cub – a node in the parallel architecture that holds the
        first block of the requested video
   Architectural Consideration
   Video Servers and Streaming
   Multimedia Communication
   Client-Design Issues
   Content Adaptation
   Summary
Multimedia Communication
   Considerable features in a distributed
    multimedia system
       Remote Control
       Unreliable communication handling
       Adaptation of the storage and streaming to
        different applications, network bandwidth, and
        devices
       Data compression and decoding for multiple
        platforms
       Secure communication, authentication, and
        copyright protection
Reservation vs. Reservationless
Protocols
   IPv4 protocol cannot guarantee on-time
    delivery of time-sensitive information
   Reservation-based:
       Resources are reserved explicitly
       The network classifies incoming packets and uses the
        reservations made to provide a differentiated service
       RSVP (Resource Reservation Protocol), IPv6
   Reservationless:
       No resources are explicitly reserved
       Traffic is differentiated into a set of classes, and the network
        provides services to these classes based on their priority
       Flow Label and Priority fields in IPv6
Real-Time Delivery Protocols
   Realtime Transport Protocol (RTP)
       IP-based protocol providing support for the
        transport of real-time data such as video and
        audio streams
       Time reconstruction, loss detection, security, and
        content identification
       RTSP (Real-Time Streaming Protocol) is C-S
        multimedia presentation protocol to enable
        controlled delivery of streamed multimedia data
        over IP networks. It provides VCR-style remote
        control functionality
Secure MM Communication
   The network infrastructure support security
    to appropriate levels to protect customers
    and ensure privacy
       Authentication, verification, and copyright
        protection
       MPEG encryption
       Digital watermarking
Reliable MM Communication
   An error-control mechanism
       Mostly used with error-prone wireless links
   Two basic approaches
       FEC (Forward Error Correction): adding parity bits
        to the transmitted packets, and this redundancy is
        used by the receiver to detect and correct errors
       ARQ (Automatic Repeat Request): maintaining
        constant throughput and having bounded time
        delay. Only for error detection capability
   Architectural Consideration
   Video Servers and Streaming
   Multimedia Communication
   Client-Design Issues
   Content Adaptation
   Summary
Client-Design Issues
   The design of the client will be dominated by
    questions of cost, functionality, and convenience.
       Metadata is used for interactive television with MPEG-4 and
        MPEG-7
       Synchronization of different streams of audiovisual
        document
   Example
       IST SAMBITS: providing digital video broadcasting (DVB)
        with complementary Internet services to set-top boxes at
        home
   Multimedia software frameworks
       JMF for Java, MET++ for C++
JMF: Java Media Framework
   JMF is API for creating Java programs enabled to
    play back a wide variety of time-based media formats
   JMF can be used to
       Play multimedia files in a Java application or applet and play
        streaming media format from the Internet
       Capture audio and video with a microphone and video
        camera, then store the data in a format supported by JMF
       Transmit audio and video on the Internet, broadcast live
        radio and television programs
       Process time-based media; for example, build a chain of
        analysis tools that perform content adaptation, video
        segmentation, render the video for display, and so on
   Architectural Consideration
   Video Servers and Streaming
   Multimedia Communication
   Client-Design Issues
   Content Adaptation
   Summary
Content Adaptation
   Content Adaptation
       To guarantee for an end-to-end QoS over a variety of heterogeneous
        network domain devices
       Dynamic content adaptation of the media quality to the level admitted by
        the network
       The quality of a media object refers to the resolution of an object and its
        play rate
   Client-Server MM system with Content Adaptation
Content Adaptation in MPEG-4
   Translation: conversion from one modality to another
   Summary: reduction of information details
   Scaling: operations of data transcoding,
    manipulation, and compression
   Extraction: extraction of information from the input
   Substitution: one representation can be used to
    substitute another
   Revision: AV program was revised in some way, such
    as through editing or postprocessing
Adaptive Virtual Video Server
   The adaptive virtual video server provides a
    means for component adaptation
       Step 1: Content Indexing
            1a: the media is analyzed for semantic and structural
             content
            1b: the media is analyzed for its adaptation capabilities
       Step 2: Delivery
            2a: the media server contacts the metadatabase for
             description
            2b: these description is attached to the media stream
             and delivered to the client
Metadata-driven adaptation
   Adaptive Proxy Cache
   Adaptive Routers
   Adaptive Query and Presentation
    Interface
Summary
   Distributed multimedia database technologies involve
    network technology, distributed control, multimedia
    security, multimedia computing, and multimedia
    content adaptation
   VoD systems including video streaming server
    technology
   Multimedia communication and synchronization
   Client-design issues: mainly hardware and software
    requirements and implementations
   Multimedia content adaptation