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Multimedia Technology

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HDTV decoders. DVD players. Video conferencing. Internet video. Other applications. MPEG ... MPEG-2 (DVD, Digital TV) MPEG-4 (All Inclusive and Interactive) ... – PowerPoint PPT presentation

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Title: Multimedia Technology


1
Multimedia Technology
  • Soochow University Library
  • Chen Jiacui

2
Multimedia
  • Multimedia is the term used to describe two or
    more types of media combined into a single
    packageusually denoting a combination of some or
    all of the following video, sound, animation,
    text, and pictures.

3
Multimedia Technology
  • And with the advent of multimedia, the computer
    has evolved into a distinctive medium that is
    uniquely capable of juxtaposing text, images,
    audio, and video.

4
Business Process Convergence
  • Technology convergence
  • Devices, networks, services and multimedia
    content (movies, TV, gaming, music).
  • Business convergence
  • Business models, pricing simplicity,
    billing, payment, etc.

5
Outline
  • Multimedia Data Compression
  • Trends of multimedia technology

6
Multimedia Data Compression
  • Still Image Compression Standards
  • Basic Video Compression Techniques
  • MPEG Video Compression
  • MPEG audio standards

7
Still Image Compression Standards
  • JPEG Joint Photographic Experts Group
  • Lossy compression of still images
  • Lossless compression of still images
  • JBIG Joint Bilevel Image Group
  • GIF Graphics Interchange Format
  • PNG Portable Network Graphics

8
JPEG
  • JPEG is a standardized image compression
    mechanism. It is designed for compressing either
    full-color or gray-scale images of natural,
    real-world scenes. It works well on photographs,
    naturalistic artwork, and similar material not
    so well on lettering, simple cartoons, or line
    drawings. JPEG handles only still images.
  • Important Properties
  • Setting compression parameters
  • Trade off decoding speed against image quality

9
Setting compression parameters
File save generates factors 1.3, 2.45, 6.87
10
Image accuracy
Quality level 90 File size 10,582 bytes
Quality level 1 File size 923 bytes
Quality level 50 File size 5,154 bytes
11
Lossy compression
  • JPEG is "lossy compression", in which some amount
    of data is lost. Lossy compression technologies
    attempt to eliminate redundant or unnecessary
    information. Most video compression technologies
    use a lossy technique.

12
JPEG JPEG 2000
  • JPEG 2000 improved the following deficiencies
  • Poor subjective performance at rates below
    0.25bits per pixel (bpp)
  • Lack of ability to provide lossy and lossless
    compression in the same codestream
  • Lack of robustness to bit errors in the
    compressed image
  • Poor performance with computer-generated imagery
  • Poor performance with compound documents (text
    and image)

13
JPEG JPEG-LS
  • JPEG-LS provides lossless and near lossless modes
    of operation
  • The near lossless mode allow users to specify a
    bound (referred to as NEAR) on the error
    introduced by the compression algorithm.
  • JPEG-LS exploits local structure and repetitive
    context within images to achieve efficient
    lossless and near lossless compression.

14
JBIG
  • JBIG (Joint Bi-level Image Group) is an advanced
    compression scheme utilizing lossless, predictive
    methods. The JBIG compression algorithm is
    defined by ISO/IEC S 115441999. It defines the
    compression scheme not the file format.

15
The main characteristic of JBIG
  • Compatible progressive/sequential coding. This
    means progressively coded image can be decoded
    sequentially and the other way around
  • JBIG will be a lossless image compression all
    bits in the image before and after the
    compression and decompression will be exactly the
    same.

16
JBIG2
  • The JBIG2 provides a highly effective method for
    lossless compression of a generic bilevel image
  • JBIG2 is the improved version of JBIG
  • The JBIG2 takes advantage of the properties of
    the source material.
  • It gives the user option of using lossy
    compression, which increase the amount of
    compression that can be obtained.

17
GIF
  • A standard defining a mechanism for the storage
    and transmission of raster-based graphics
    information.
  • The GIF method is lossless it reproduces exactly
    the pixels that were in the original image upon
    viewing.

18
GIF
  • GIF is better than JPG for images with only a few
    distinct colors, such as line drawings, black and
    white images and small text that is only a few
    pixels high. With an animation editor, GIF images
    can be put together for animated images.
  • GIF also supports transparency, where the
    background color can be set to transparent in
    order to let the color on the underlying Web page
    to show through.
  • The compression algorithm used in the GIF format
    is owned by Unisys, and companies that use the
    algorithm are supposed to license the use from
    Unisys.

19
PNG
  • A file format for bitmapped graphic images,
    designed to be a replacement for the GIF format,
    without the legal restrictions associated with
    GIF.

20
Basic Video Compression Techniques
  • H.261
  • H.261 is an earlier digital video compression
    standard, its principle of MC-based compression
    is retained in all later video compression
    standards. The standard was designed for
    videophone, videoconferencing and other
    audiovisual services over ISDN.
  • H.263
  • H.263 is an improved video coding standard for
    videoconferencing and other audiovisual services
    transmitted on Public Switched Telephone Networks
    (PSTN).

21
MPEG
  • MPEG is used for coding audio-visual information
    in a digital compressed format. The MPEG family
    of standards includes MPEG-1, MPEG-2 , MPEG-4,
    MPEG-7, and MPEG-21.

22
MPEG
  • Digital television set-top boxes
  • DSS
  • HDTV decoders
  • DVD players
  • Video conferencing
  • Internet video
  • Other applications

23
MPEG
  • MPEG-1 (Video CDs
  • MPEG-2 (DVD, Digital TV)
  • MPEG-4 (All Inclusive and Interactive)
  • MPEG-7 (Meta-Data)
  • MPEG-21 (Digital Rights Infrastructure)

24
MPEG audio standards
  • Layer 1
  • Lossless compression of subbands optional
    simple masking model
  • Layer 2
  • More advanced masking model.
  • Layer 3
  • Additional processing for lower bit rates.

25
Trends of multimedia technology
  • Multimedia content analysis, processing, and
    retrieval
  • Multimedia networking and systems support
  • Multimedia tools, end-systems, and applications
    and
  • Foundational sciences of multimedia.

26
Content Analysis
  • Image, audio and video characterization (feature
    extraction)
  • Fusion of text, image, video and audio data
  • Semantic image/video/audio classification
  • Multimedia semantics modeling
  • Image, video and audio similarity measures
  • Unconstrained object and face detection/recognitio
    n
  • Low- and high-level temporal video segmentation
  • Benchmarking of content analysis methods and
    algorithms
  • Generic methods and algorithms for content
    analysis and semantics modeling
  • Affective content analysis.

27
Multimedia Content Processing
  • Speech Processing and Recognition
  • Audio Enhancement
  • Restoration and Analysis
  • Image Representation and Modelling
  • Image Restoration and Enhancement
  • Colour Vision, 3D Vision, Image and Video
    Analysis
  • Pattern Recognition
  • Watermarking
  • New Media.

28
Content Search/Browsing/Retrieval
  • Multimedia mining
  • Active learning and relevance feedback
    techniques
  • Query models, paradigms, and languages for
    multimedia content retrieval
  • Browsing and visualization of multimedia data
    sets
  • User interfaces for multimedia databases
  • Search issues in distributed and heterogeneous
    systems, meta-search engines
  • Benchmarking of search, browsing and retrieval
    methods and algorithms
  • Generation of video summaries and abstractions.

29
Content Management and Delivery
  • Multimedia databases
  • Efficient peer-to-peer storage and search
    techniques
  • Indexing and data organization
  • System optimization for search and retrieval
  • Storage hierarchy, scalable storage.

30
Questions?
31
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