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ECE8873 MPEG-7

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)

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ECE8873 MPEG-7

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  1. ECE8873MPEG-7 Deryck Yeung

  2. Overview • Summary of MPEG-1,MPEG-2 and MPEG-4 • Why another standard? • MPEG-7 • What’s next? • Conclusion

  3. Origin of MPEG (Movie Picture Expert Group) An Evolution Theory of MPEG

  4. MPEG-1 MPEG-1

  5. 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

  6. MPEG-2 MPEG-2 MPEG-1

  7. Summary MPEG-2 • MPEG-2(1990-1995) - Higher bit rate at 80Mbps - mainly broadcast - Application in DVD, HDTV etc. - Backward compatibility with MPEG-1

  8. MPEG-3 MPEG-3 MPEG-2 MPEG-1

  9. MPEG-3 MPEG-3 MPEG-2 MPEG-1

  10. MPEG-4 MPEG-4 MPEG-2 MPEG-1

  11. 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.

  12. Q&A session: Do we need another standard? If so, why?

  13. 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 asoutput of a filter.

  14. 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} • Hence, we have a different (more efficient) representation of the waveform. Represented by

  15. Why MPEG-7? • Now look at transform coding. Data block ---------------------> ------------ -------- • Transform allows data to be ‘rotated’ to bring out the structure of the waveform for efficient coding. New representation T Q T-1

  16. 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 • {sinusoid} {ω0, 2 FS coefficients.} Represented by

  17. Big picture so far. waveform New representation quantization

  18. Why MPEG-7?

  19. 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’.

  20. Why MPEG-7? waveform New representation quantization ?

  21. Why MPEG-7? waveform New representation quantization MPEG-7 description

  22. 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.

  23. 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.

  24. Scope

  25. 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.

  26. 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.

  27. Big picture now

  28. Description Tools: • Over 100 description tools (just like Matlab toolboxes) have been defined. They can be divided as follows:

  29. Example: • One DS in “content description” ‘toolbox’ is the Segment DS.

  30. Another example: SegmentRelationship DS

  31. 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.

  32. 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.

  33. 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)

  34. Problem in searching • Let’s go back to the problem of searching using MPEG-7

  35. Other uses of MPEG-7 • Digital libraries • Multimedia directory services (e.g. Tourist information, Geographical information systems) • Home Entertainment • And many more!

  36. What has been done so far • The ‘wrapping’ effect of all these MPEG standards.

  37. 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.

  38. 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)

  39. 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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