1 multimedia communications 1 zlecturer: prof. xinhua zhuang zcecs & ee departments zuniversity...
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Multimedia Communications
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Lecturer: Prof. Xinhua Zhuang CECS & EE Departments University of Missouri Columbia, MO 65211
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The Multimedia Experience
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Daily Newspaper TV Program Video-on-demand Video Animation Virtual Meeting Room Distance Learning Virtual Library Living Books
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Multimedia
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including or involving the use of several media of communication, entertainment, or expression
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Multimedia vs. Multiple Media
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Multiple Media: unique delivery mechanism, unique repository or mailbox electronic mail voice mail data files
Multimedia: single repository messages with integrated text, sound, images, video,
data files, handwriting single access mechanism handling all media
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Multimedia Communications
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basic currency of communications switches from narrowband voice telephony to seamlessly integrated, high quality, broad-band transmission of multimedia signals
basic access method switches from wireline connections to combinations of wired and wireless (copper cable, ber, cell sites, satellite, and electrical power lines)
basic mode of communications expands from people-to-people communications to include people-to-machine communications
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Driving Forces in Multimedia Communications
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evolution of communications and data networks into modern POTS (plain old telephone service) and PACKET (a data unit belonging to level 3 of the ISO (International Standards Organization) reference model) networks, and further into an integrated structure
increasing availability of almost unlimited bandwidth on demand in both the office and the home, and eventually on road, due to proliferation of high speed data modems, cable modems, hybrid fiber-coax systems, and fixed wireless access systems
availability of ubiquitous (anywhere, anytime) access to network via LANs, and wireline and wireless networks
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Driving Forces in Multimedia Communications
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ever increasing amount of memory and computing power brought to bear on virtually any communications and computing systems
proliferation of smart terminals such as sophisticated screen phones, digital telephones, multimedia PCs natively handling a wide range of text, image, audio, and video signals
digitization of virtually all devices such as cameras, video capture devices, handwriting terminals, sound capture devices
standards for interconnections and communications between all devices attached to the network
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Where are we Today?
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Where are we Today?
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POTS: good for narrowband voice trac PACKET: good for data trac Services are separate for POTS and PACKET Networks Control is separate for POTS and PACKET Networks
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Tomorrow's Network
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intelligence inside network intelligence at the desktop intelligence at the terminal ubiquitous services works with all types of access devices such as telephones,
PC's
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Technology Aspects of MM Systems
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compression and coding of multimedia signals; standards organizing, storing, and retrieving multimedia signals;
streaming (real time transmission of multimedia signals), layering, QoS (Quality of Service) issues
accessing multimedia signals by matching the user to the machine; GUI (graphical user interface), SLI (spoken language interface), media conversion, agents
searching multimedia archives and databases based on machine intelligence; text, image, speech
browsing multimedia archives and documents based on human intelligence; text, image, audio, video
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Illustrative Multimedia Systems
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teleconferencing systems which integrate voice, video, application sharing, data sharing
FusionNet service which integrates the POTS and PACKET networks by exploiting Internet search and VCR-like features for viewing video, with POTS access to video content
CYBRARY digital virtual library which aims to provide a digital library experience which is better than being there live
Pictorial Transcripts system which provides a content-based sampled representation of video over the Internet
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Technology Assumptions
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multimedia processing is a lot more than compression and coding
multimedia applications need to be standard-based handling (delivery, display) of multimedia signals is crucial user interface is critical to usability of most applications multimedia experience is shared between people and
machines
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Image Coding Principles
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spatial redundancy repeated patterns image correlations in space spectral correlations
temporal redundancy repeated objects in video sequence predictable moves of objects
take advantage of human visual system perceptual masking of intensity, color, texture, time sequence
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Image Coders: FAX
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Group 3 FAX: simple 1-D search Group 4 FAX: simple 2-D search JBIG-1: prediction based on local neighborhood JBIG-2: soft pattern matching on segmented regions
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Image Coders: Continuous Tone
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JPEG block-based DCT psychophysically based scalar quantization entropy coding
JPEG-2000 modern architecture and standard downloadable software handles a broad range of conditions
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JPEG Performance
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8:1 Indistinguishable 10.7:1 Excellent 21.4:1 Very Good 32:1 Good 64:1 Fair
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Video Coders
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H.261, H.262, H.263: motion compensated coder for interframe coding
MPEG-1: multimedia standard with specifications for coding, compression and transmission of audio, video, and data streams in a series of packets
MPEG-2: multimedia standard with capability of compressing, coding and transmitting high quality, multi-channel multimedia signals over broadband networks
MPEG-4: object-based approach to multimedia with independent coding of objects, interactive compression of objects, ability to integrate synthetic and natural objects
MPEG-7: searching, indexing, authentication of large databases
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Video Coding
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video conferencing: H.261 for ISDN, H.263 for POTS movie storage on CDROM: MPEG-1, 1.2 Mb/s for video, 256
kb/s for audio broadcast video on DVD (digital video disk): MPEG-2, 2-15
Mb/s for video/audio low bit rate telephony over POTS network: MPEG-4, 10 kb/s
for video, 5.3 kb/s for voice HDTV with 15-400 Mb/s for video
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Searching of Multimedia Documents
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text-based indexing structured (field-based) in databases SQL (Structured Query
Language) queries unstructured or natural language text full text search
uses inverted index for each word; records document and location can do partial matches can find word variants
information extraction from documents speech indexing
full recognition of text (error prone) event detection (word spotting) speaker identification used to align speech and text
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Searching of Multimedia Documents
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audio indexing start and end of speech musical signatures for instruments singing voice
image indexing classification by color and brightness histograms, texture,
extracted shapes hand-drawn description of image content figure captions, textual description of image content
video indexing
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Browsing of Multimedia Documents
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text-based browsing table of contents, index, skimming
image-based browsing find image of interest, examine associated text
scene-based browsing find place in video for full search or editing
video skimming browsing high speed playback
audio skimming browsing high speed playback
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Multimedia Conferencing
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FusionNet Concept
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High quality audio/video over the network Internet provides vast development and information
resources for browsing, searching POTS provides guaranteed QoS transmission with security
and billing Client needs to gain access to both the Internet and POTS Server needs to gain access to both the Internet and POTS
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The CYBRARY Project at AT&T
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virtual presence in a library see documents in their original form on any screen
connected to the Internet create a new standard for document image compression
(DJVU) geared towards screen display rather than printing efficient document compression allows fast page flipping
and browsing OCR allows full text search and indexing
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Pictorial Transcripts
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Fully automatic generation of multimedia document from full motion video source material
Enables broadcasters to go on-line with no additional manual effort
Generate content for network-based hosting service
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Summary
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multimedia is more than multiple media multimedia merges computing, communications, and
information sciences multimedia depends on networking, computation, and
memory multimedia depends on compression, standards, user
interfaces, searching, and browsing multimedia involves integration, systems, testing, and
conformance testing