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05MSE E13- Multi Media Computing

05MSE E13- Multi Media Computing. By U.RAHAMATHUNNISA ASSISTANT PROFESSOR SITE. Introduction. Multimedia Description Why multimedia systems? Classification of Media Multimedia Systems Data Stream Characteristics. Multimedia Description.

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05MSE E13- Multi Media Computing

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  1. 05MSE E13- Multi Media Computing By U.RAHAMATHUNNISA ASSISTANT PROFESSOR SITE

  2. Introduction • Multimedia Description • Why multimedia systems? • Classification of Media • Multimedia Systems • Data Stream Characteristics

  3. Multimedia Description • Multimedia: is an integration of continuous media (e.g. audio, video) and discrete media (e.g. text, graphics, images) through which digital information can be conveyed to the user in an appropriate way. • Multimedia technology is the computer-based integration of text, sound, still images, animation and digitized motion video. • Merges capabilities of computers with televisions, VCRs, CD players, DVD players, video and audio recording equipment, music and gaming technologies. CIS 104

  4. Why Multimedia Computing? • Application driven • e.g. medicine, sports, entertainment, education • Information can often be better represented using audio/video/animation rather than using text, images and graphics alone. • Information is distributed using computer and telecommunication networks. • Integration of multiple media places demands on • computation power • storage requirements • networking requirements CIS 104

  5. Multimedia Information Systems • Technical challenges • Sheer volume of data • Need to manage huge volumes of data • Timing requirements • among components of data computation and communication. • Must work internally with given timing constraints - real-time performance is required. • Integration requirements • need to process traditional media (text, images) as well as continuous media (audio/video). • Media are not always independent of each other - synchronization among the media may be required. CIS 104

  6. High Data Volume of Multimedia Information CIS 104

  7. Technology Incentive • Growth in computational capacity • MM workstations with audio/video processing capability • Dramatic increase in CPU processing power • Dedicated compression engines for audio, video etc. • Rise in storage capacity • Large capacity disks (several gigabytes) • Increase in storage bandwidth,e.g. disk array technology • Surge in available network bandwidth • high speed fiber optic networks - gigabit networks • fast packet switching technology CIS 104

  8. Application Areas • Residential Services • video-on-demand • video phone/conferencing systems • multimedia home shopping (MM catalogs, product demos and presentation) • self-paced education • Business Services • Corporate training • Desktop MM conferencing, MM e-mail CIS 104

  9. Application Areas • Education • Distance education - MM repository of class videos • Access to digital MM libraries over high speed networks • Science and Technology • computational visualization and prototyping • astronomy, environmental science • Medicine • Diagnosis and treatment - e.g. MM databases that provide support for queries on scanned images, X-rays, assessments, response etc. CIS 104

  10. Classification of Media • Perception Medium • How do humans perceive information in a computer? • Through seeing - text, images, video • Through hearing - music, noise, speech • Representation Medium • How is the computer information encoded? • Using formats for representing and information • ASCII(text), JPEG(image), MPEG(video) • Presentation Medium • Through which medium is information delivered by the computer or introduced into the computer? • Via I/O tools and devices • paper, screen, speakers (output media) • keyboard, mouse, camera, microphone (input media) CIS 104

  11. Classification of Media (cont.) • Storage Medium • Where will the information be stored? • Storage media - floppy disk, hard disk, tape, CD-ROM etc. • Transmission Medium • Over what medium will the information be transmitted? • Using information carriers that enable continuous data transmission - networks • wire, coaxial cable, fiber optics • Information Exchange Medium • Which information carrier will be used for information exchange between different places? • Direct transmission using computer networks • Combined use of storage and transmission media (e.g. electronic mail). CIS 104

  12. Media Concepts • Each medium defines • Representation values - determine the information representation of different media • Continuous representation values (e.g. electro-magnetic waves) • Discrete representation values(e.g. text characters in digital form) • Representation space determines the surrounding where the media are presented. • Visual representation space (e.g. paper, screen) • Acoustic representation space (e.g. stereo) CIS 104

  13. Media Concepts (cont.) • Representation dimensions of a representation space are: • Spatial dimensions: • two dimensional (2D graphics) • three dimensional (holography) • Temporal dimensions: • Time independent (document) - Discrete media • Information consists of a sequence of individual elements without a time component. • Time dependent (movie) - Continuous media • Information is expressed not only by its individual value but also by its time of occurrence. CIS 104

  14. Multimedia Systems • Qualitative and quantitative evaluation of multimedia systems • Combination of media • continuous and discrete. • Levels of media-independence • some media types (audio/video) may be tightly coupled, others may not. • Computer supported integration • timing, spatial and semantic synchronization • Communication capability CIS 104

  15. Data Streams • Distributed multimedia communication systems • data of discrete and continuous media are broken into individual units (packets) and transmitted. • Data Stream • sequence of individual packets that are transmitted in a time-dependant fashion. • Transmission of information carrying different media leads to data streams with varying features • Asynchronous • Synchronous • Isochronous CIS 104

  16. Data Stream Characteristics • Asynchronous transmission mode • provides for communication with no time restriction • Packets reach receiver as quickly as possible, e.g. protocols for email transmission • Synchronous transmission mode • defines a maximum end-to-end delay for each packet of a data stream. • May require intermediate storage • E.g. audio connection established over a network. • Isochronous transmission mode • defines a maximum and a minimum end-to-end delay for each packet of a data stream. Delay jitter of individual packets is bounded. • E.g. transmission of video over a network. • Intermediate storage requirements reduced. CIS 104

  17. Data Stream Characteristics • Data Stream characteristics for continuous media can be based on • Time intervals between complete transmission of consecutive packets • Strongly periodic data streams - constant time interval • Weakly periodic data streams - periodic function with finite period. • Aperiodic data streams • Data size - amount of consecutive packets • Strongly regular data streams - constant amount of data • Weakly regular data streams - varies periodically with time • Irregular data streams • Continuity • Continuous data streams • Discrete data streams CIS 104

  18. Classification based on time intervals Strongly periodic data stream T Weakly periodic data stream T1 T2 T3 T T Aperiodic data stream T1 T2 CIS 104

  19. Classification based on packet size D1 T t Strongly regular data stream D1 D1 T D2 Weakly regular data stream D3 t D1 D2 D3 D1 D2 Irregular data stream t D3 Dn CIS 104

  20. Classification based on continuity Continuous data stream D1 D2 D3 D4 D D1 D2 D3 D4 D Discrete data stream CIS 104

  21. Logical Data Units • Continuous media consist of a time-dependent sequence of individual information units called Logical Data Units (LDU). • a symphony consists of independent sentences • a sentence consists of notes • notes are sequences of samples • Granularity of LDUs • symphony, sentence, individual notes, grouped samples, individual samples • film, clip, frame, raster, pixel • Duration of LDU: • open LDU - duration not known in advance • closed LDU - predefined duration CIS 104

  22. Granularity of Logical Data Units Film Clip Frame Blocks Pixels CIS 104

  23. Multimedia from a user‘s point of view • Presentation of Information also using Audio and Animation • Information is easier conveyed • Integration of Media with the Computer allows for • Interactive Presentations • Transmission across computer networks CIS 104

  24. Multimedia and the Industry Sectors affected by the developments in Multimedia • Telecommunications • Consumer Electronics • TV- and Radiostations • Publishing Houses => Convergence of Sectors CIS 104

  25. Properties of multimedia processing • High data troughput • Realtime • Synchronisation CIS 104

  26. Global Structure/Areas in Multimedia-Systems Databases Operating Systems Communication System Computer Technology Memory Networks Compression Audio Video CIS 104

  27. Areas in Multimedia-Systems User Interface Applications Documents Abstractions CIS 104

  28. Terminology • Multi [lat. much], as a Prefix • Medium, mediating element, means to reproduce Information CIS 104

  29. The term „medium“ • Means for the distribution and presentation of information • Examples: Text, Figure, Image, Voice, Music • Further differentiation of the term in the MHEG-Standard (1993) • On the following two slides CIS 104

  30. Different media terms • Perception-Medium • To See, to Hear (how?) • Representation-Medium • JPEG, MPEG (Structure, Coding) • Presentation-Medium • Screen, Speakers, Keyboard (Input/Output) CIS 104

  31. Different media terms • Storage-Medium • Paper, Harddisk, CD-ROM (where from?) • Transmission-Medium • Network (on what?) • Information-Exchange-Medium • Transmitter / Storage of Information: CD, Network (higher abstraction) CIS 104

  32. Presentation values and domains • Presentation domains • Screen, Paper (visual presentation domains) • Stereophonetics • Presentation values • Character, shock wave CIS 104

  33. Presentation dimension • Every presentation domain has presentation dimensions • Screen: 2 spatial dimensions • In Addition, Time as a dimension possible • Time as additional dimension fundamental for multimedia systems CIS 104

  34. Classes of media • Classification using the time dimension • Discrete Media • Independent from time • Examples: Text, Figures • Continuous Media • Dependent on time • Examples: Sound, Motion Picture CIS 104

  35. The Term „Multimedia“ • Qualitative rather than quantitative understanding • What kind of media instead of multiple media • A Combination of text and picture is not sufficient for the term „Multimedia“ • „Controversial term“ CIS 104

  36. Main properties of a multimedia system • Combination of Media • Processing of discrete and continuous media • Independency • in the layout of the media in space and time • Computerized Integration • Computer as a tool • (Systems able to communicate) • Distributed Multimedia-Systems CIS 104

  37. Definition of „Multimedia“ • A multimedia system is defined through the computerized, integrated creation, manipulation, presentation, storage and communication of independent information coded in at least one continuous and one discrete medium. CIS 104

  38. Usage of the term „Multimedia“ • In a narrow sense • Continuous Media • Borders in Time • In a broader sense • Shared processing of multiple media CIS 104

  39. Transmission of media data • Transmission of data of discrete and continuous media • For information exchange • Based on data streams CIS 104

  40. Data stream • Units (Packets) • Send from source to sink • Data stream is a sequence of single packets • For discrete and continuous media CIS 104

  41. Asynchronous Transmission • No restrictions in time for the packets of the data stream • Example: IP • Normally not suitable for multimedia CIS 104

  42. Synchronous Transmission • Defined Maximum End-To-End Latency • For multimedia this means a guarantee on when packets will be arriving CIS 104

  43. Isochronous Transmission • Defined maximum and minimum end-to-end latency • Jitter of single packets is restricted • Buffers can be calculated more exact • Suitable for „Streaming“, transmission of very large amounts of data CIS 104

  44. Data streams of continuous media • Different Properties • Time interval between packets • Amount of data / size of packets • Correlation of packets • Possibly because of compression • Example: Audio- and video transmission CIS 104

  45. Strongly periodic data stream • Time interval between neighbouring packets is constant • Example: Voice in a telephone operation system T CIS 104

  46. Weakly periodic data stream • Time interval between packets follows a function of finite period duration • Example: Animation T1 T2 T3 T1 T2 T CIS 104

  47. Aperiodic data stream • Neither strongly nor weakly periodic • Example: Transmission of events (e.g. Mouse interactions) • • • T1 T2 Tn CIS 104

  48. Strongly regular • Constant amount of data of all packets D1 Dn t CIS 104

  49. Weakly regular • Amount of data of packets varies periodicly D1 D2 D3 T D1 D2 t D3 CIS 104

  50. Not regular • Amount of data is neither constant nor periodic D1 D2 D3 • • • t Dn CIS 104

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