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					  ECE8873
  MPEG-7


Deryck Yeung
Overview

   Summary of MPEG-1,MPEG-2 and
    MPEG-4
   Why another standard?
   MPEG-7
   What‟s next?
   Conclusion
Origin of MPEG (Movie Picture
Expert Group)

   An Evolution Theory of MPEG
 MPEG-1

MPEG-1
Summary MPEG-1
   MPEG-1(1988-1993)
    -Goal: coding of moving picture with
    associated audio at rate up to 1.5Mbps
    -Entertainment and storage
    -Video storage with 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
 MPEG-1
Summary MPEG-2
   MPEG-2(1990-1995)
    - Higher bit rate at 80Mbps
    - mainly broadcast
    - Application in DVD, HDTV etc.
    - Backward compatibility with MPEG-1
MPEG-3

                   MPEG-3
          MPEG-2
 MPEG-1
MPEG-3

                   MPEG-3
          MPEG-2
 MPEG-1
MPEG-4
                   MPEG-4
          MPEG-2
 MPEG-1
Summary MPEG-4
   MPEG-4 embraces several areas:
       Coding of visual objects
       Coding of audio objects
       Scene description and user interaction
   Most important: object coding
   This set the stage for MPEG-7.
Q&A session:

  Do we need another standard?
          If so, why?
Why MPEG-7?
   Let‟s take a step back!
   Almost all standards up to this point
    involve either some form of waveform
    coding (e.g. linear prediction etc) or
    transform coding (e.g. DCT etc).
   Look at linear prediction, for example.
   Speech waveforms are modeled as
    output of a filter.
Why MPEG-7?
   Now, given the input to the filter and
    the filter coefficients we can reconstruct
    the waveform, albeit with some
    distortion.
   {Waveform }          {input, filter coeffs}
                  Represented
                       by



   Hence, we have a different (more
    efficient) representation of the
    waveform.
Why MPEG-7?
   Now look at transform coding.
                             New
                        representation
    Data block
                  T   --------------------->
                                               Q   ------------
                                                                   T-1   --------




   Transform allows data to be „rotated‟ to
    bring out the structure of the waveform
    for efficient coding.
Why MPEG-7?
   Classical Fourier Series expansion is an
    example
       Need uncountably infinite number of
        „samples‟ to represent a sinusoid in time
        domain
       Fourier series expansion needs only 3
        parameters to represent the same signal
                     Represented

       {sinusoid}        by
                            {ω0, 2 FS coefficients.}
Big picture so far.
           waveform




              New
         representation




          quantization
Why MPEG-7?
Why MPEG-7?
   One motivation for MPEG-7 is to allow
    meaningful search for data.
   We are missing one thing in our picture.
   MPEG-7 allows us to go one step
    further.
   It gives meaning to the „bits‟ by
    allowing metadata.
   Or „information‟ about „information‟.
Why MPEG-7?
        waveform




           New
                       quantization
      representation




            ?
Why MPEG-7?
        waveform




           New
                       quantization
      representation



             MPEG-7




       description
Link between MPEG-4 and
MPEG-7
   MPEG-4 codes contents as objects.
   But an object can be described in many
    different ways, just like how we can describe
    the object „apple‟ in for example French,
    English, Russian etc.
   MPEG-7 defines the „universal language‟ as to
    how these objects are described and the
    „grammar‟ as to how „sentences‟ of these
    objects can be made.
MPEG-7(1998-2001)
   Also known as ‟Multimedia Content Description
    Interface‟.
   An ISO/IEC standard
   Strictly speaking, MPEG-7 is not a data compression
    scheme.
   MPEG-7 is mainly a software implementation.
   MPEG-7 specifies the rules as to how to describe
    audiovisual data content whereas MPEG-1,2 and 4
    make content available.
   MPEG-7 is not targeted at specific application. It aims
    to be as generic as possible for further extension.
Scope
Main elements
   MPEG-7 consists of 3 parts:
       Description tools (like tool box in Matlab):
         -Descriptors (D)
         -Description Schemes (DS).
       Description Definition Language (DDL).
       System tools.
Multimedia Description Tools:
    Descriptors (D):
         just like „data types‟ in Matlab
         Describes low-level audio or visual features such as
          color, motion, texture etc as well as audiovisual content
          such as location, time etc
    Description Schemes (DS):
         Just like „functions‟ in Matlab
         Describes high-level audiovisual (AV) features such as
          regions, segments, events etc. DS not only describes
          relationships among D‟s, but relationships among basic
          DS‟s as well.
Big picture now
Description Tools:
   Over 100 description tools (just like
    Matlab toolboxes) have been defined.
    They can be divided as follows:
                                          Collections               Models              User
       Content organization                                                          interaction


                                                                      Navigation &      User
                                  Creation &                            Access
                                  Production                                         Preferences
                                                                       Summaries
             Media                                         Usage
                              Content management                                       User
                                                                         Views        History
                              Content description
                     Structural                 Semantic
                                                                       Variations
                      aspects                    aspects



        Basic elements
           Schema                   Basic           Links & media      Basic
            Tools                 datatypes          localization      Tools
Example:
   One DS in “content description”
    „toolbox‟ is the Segment DS.
Another example:
SegmentRelationship DS
Other Multimedia Description
Tools
   MPEG-7 have a general set of
    multimedia Description Tools.
   From this general set 2 other sets are
    defined:
       MPEG-7 Visual: Description tools dealing
        with only visual description.
       MPEG-7 Audio: Description tools dealing
        with only audio description.
Description Definition
Language (DDL).
   DDL is based on XML schema Language.
   Since XML is not specifically designed for
    audiovisual description and real-time usage, it
    has been extended by MPEG-7 to suite the
    purpose.
   DDL defines syntax as to how D‟s and DS‟s
    can be described and combined.
   DDL allows designers to create their own D‟s
    and DS‟s.
System Tools
   A set of tools that support binary
    representation of D‟s and DS‟s.
   Broadly, they are divided into 2 groups:
       Textual format (TeM)
       Binary format (BiM)
Problem in searching
   Let‟s go back to the problem of
    searching using MPEG-7
Other uses of MPEG-7
   Digital libraries
   Multimedia directory services (e.g.
    Tourist information, Geographical
    information systems)
   Home Entertainment
   And many more!
What has been done so far
   The „wrapping‟ effect of all these MPEG
    standards.
What is next?
   MPEG is developing another standard,
    called MPEG-21.
   Alternatively known as „Multimedia
    Framework‟.
   The goal is interoperability.
   It promises an environment where
    delivery and use of all content types will
    be possible.
Summary
   Development of MPEG family
       MPEG-1 and MPEG-2 are data compression
       MPEG-4 is the start to toward data
        description (object coding).
       MPEG-7 is data description
   Move from merely data compression to
    data description
   Next step is interoperability (MPEG-21)
Bibliography
   Tarbell, Richard: MPEG-1 slides
   Tian, Dihong: MPEG-2 slides
   Dechaza, Olivier: MPEG-4 slides
   Martinez,Jose: „MPEG-7 Overview‟
   Chiariglione, Leonardo: „MPEG: achievements and current work‟
   Chiariglione, Leonardo: „The MPEG generation, new information-
    age elements‟
   Koenen, Rob: „Object-based MPEG offers flexibility‟ at
    www.eetimes.com
   Day, Neil; Martinez Jose: „Introduction to MPEG-7(V4.0)‟
   http://www.chiariglione.org/mpeg/
   http://www.mpegif.org/resources.php

				
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