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Multimedia Systems Lecture1 - Introduction

Multimedia Systems Lecture1 - Introduction. Contact Information. Name : Ghada Mohamed Afify Email: ghada_cis@yahoo.com Website: http://www.4shared.com/folder/vDxTDV91/Multimedia_Systems.html. Required Textbooks. Media Coding and Content Processing, Ralf Steinmetz, Klara

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Multimedia Systems Lecture1 - Introduction

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  1. Multimedia SystemsLecture1 - Introduction

  2. Contact Information • Name :Ghada Mohamed Afify • Email: ghada_cis@yahoo.com • Website:http://www.4shared.com/folder/vDxTDV91/Multimedia_Systems.html

  3. Required Textbooks • Media Coding and Content Processing, Ralf Steinmetz, Klara • Nahrstedt, Prentice Hall, 2002. • Multimedia Systems, Ralf Steinmetz, Klara Nahrstedt, Springer • Verlag, 2004

  4. Grading

  5. Lecture Format • Help you understand important and hard Media and Multimedia • Systems concepts • Lectures do not cover everything • Students responsibility: • Attend lectures • Read textbooks • Download lectures • Assignments, Exams

  6. Course Outline • Introduction to multimedia systems. • Audio perception. • Audio representation. • Image and Graphics representation. • Digital video representation. • Basic compression techniques. • Introduction to quality of services (QoS). • Media Servers and Multimedia File Systems. • Multimedia networks. • Media synchronization.

  7. Multimedia • Information presented in multiple formats • text (structured/unstructured, hypertext, etc) • images • graphics (drawings) • animation • audio • video

  8. Audio • Wav files • Midi files • MP3 files and the Internet • Sampling rate and sampling size

  9. Graphics • Pictures, charts, drawings, photos, icons • File formats - the best are JPEG, GIF, PICT, TIFF

  10. Video • Formats - QuickTime, MPEG, wmv, ram, avi • Large amount of storage

  11. Animation • Path-based – displays the movement on an animated object onto a fixed background in a particular sequence or path. • Cell-based – creates animation by using a series of still images, each displayed in a frame or cell.

  12. Multimedia (cont.) • Interactive Multimedia: When the user is able to control what and when elements are delivered. • Hypermedia – when interactive multimedia becomes a structure of linked elements through which the learner can navigate.

  13. Multimedia Evaluation • Does the presentation get the messages across? • Does the presentation hold the interest of the viewer? • Is it easy to use? • Can a user get around the presentation easily - not get stuck on a page?

  14. GUI Design Principles • Manipulation—People want to be in charge of their actions. Objects should be moveable where appropriate and invite interaction. • See and point—Actions and navigation should be easily recognized on screen. A user should not have to consult a manual.

  15. GUI Design Principles • Feedback—A click on a button should result in some • response that lets the user know it occurred: a sound or a • change in the appearance of the button. • Forgiveness—If users make mistakes, they should be • able to undo them. All actions should be reversible.

  16. Screen Design Tips • Keep it simple • Less is More- do not clutter a slide too much • Make it BIG - a minimum of font size 18 • Pictures can be worth 1000 words • Watch your color combinations –stick to standard combinations • Sans serif fonts (Arial) easier to read than serif (Times)

  17. Multimedia systems • Systems that represent, manipulate, deliver multimedia information • Examples: • world wide web • video conferencing • interactive TV • online games • virtual reality • Speech recognition • Multimedia training and education

  18. Authoring Tools • Use to merge multimedia elements (text, audio, graphic, animation, video) into a project. • Designed to manage individual multimedia elements and provide user interaction (if required). c

  19. Authoring Tools • Example: • Macromedia Authorware • Macromedia Director • Macromedia Flash • Microsoft Power Point c

  20. Importance of Multimedia • There are a number of fields where multimedia could be of use. Examples are:- • Business • Education • Entertainment • Home • Public Places c

  21. Importance of Multimedia • Business • Use and Applications • Sales / Marketing Presentation • Trade show production • Staff Training Application c

  22. Importance of Multimedia • Education • Use and Applications • Courseware / Simulations • E-Learning / Distance Learning • Information Searching c

  23. Importance of Multimedia • Entertainment • Use and Applications • Games (Leisure / Educational) • Movies • Video on Demand • Online c

  24. Importance of Multimedia • Home • Use and Applications • Television • Satellite TV • SMS services (chats, voting, reality TV) c

  25. Importance of Multimedia • Public Places • Use and Applications • Information Kiosk • Smart Cards, Security c

  26. Multimedia Products • Briefing Products • Reference Products • Database Products • Education and Training Products • Entertainment and Games c

  27. Multimedia Products • 1. Briefing Products: • Small, straightforward, linear products used to present information. • Characteristic of briefing product: • Short Development Cycle • Limited Number of Presentations • Usage of text to present information with limited use of graphic, audio and video. • Have few navigational controls. (mouse click and button press to move from one page to another) • Content and the format are suitable for the audience and fulfill the purpose of the presentation. c

  28. Multimedia Products • 1. Briefing Products: • Good briefing presentation depends on: • The understanding of the presented subject. • Integration of content. • Consistent layout • Example: • Corporate Presentation • Sales Presentation • Educational Lectures c

  29. Multimedia Products • 2. Reference Products: • Often used for answering specific questions or for general browsing of information. • Characteristic of reference product: • Used by wide range of user (small – adult) • Have navigational menu, book marking, searching, printing utility • Examples are electronic forms of: • Encyclopedia • Dictionaries • Cookbooks, Historical, Informative • Scientific surveys. c

  30. Multimedia Products • 3-Database Products: • Similar to reference product in a sense that large amount of information are made available to the end user. • Focus on storing and accessing the actual data (multimedia data such as text, graphic, audio, animation and video) • Characteristics of Database Products are: • Manages multimedia data (large data) • Descriptive finding methods • Content based search • Simultaneous access • Online database c

  31. Multimedia Products • 3. Database Products: • Examples are: • Google Search • Google Earth c

  32. Multimedia Products • 4. Education and training products: • Similar to textbook or training manuals but have added media such as audio, animation and video. • Make up a significant share of the multimedia market ranging from pre-kindergarten to postgraduate offerings from technical to corporate training products. • Two categories of reference product: • Instructor Support Products • Standalone or Self-Paced Products • Combination Products c

  33. Multimedia Products • 5. Entertainments and Games: • Most popular • Shipped in the form of Interactive CD / DVD ROM. • Characteristics of these Products:- • Impressive. • Requires constant feedback and interaction with the user. • Challenging and sometimes exciting for user • Enabled online play for more than one user experience. Multimedia Products c

  34. Aspects of Multimedia • Capture • Representation • Storage • Transmission • Processing • Information exchange • Presentation • Perception

  35. Audio representation • How to digitize analogy audio (sound wave)?

  36. Image representation • Digital image is a 2-d array of pixels • Pixel is represented by bits in “color” space • RGB in CRT • additive color • CMY in printing • subtractive color • YUV for black-white/color TV • luminance/chrominance

  37. Video representation • Video is a sequence of images • displayed at a certain rate

  38. Why multimedia compression • “A picture is worth a thousand of words!” • so is the amount of data • One-minute audio CD clip • sampling rate: 44.1 KHz • sample size: 16-bit • channels: 2 • bit-rate: 1.4 Mbps • data size: 10.6 MB

  39. Generic data compression • Lossless compression • no information loss • example: executable file compression • relatively low compression ratio • Lossy compression • may lose some information • example: multimedia data compression • usually higher compression ratio

  40. Multimedia compression • There is (a lot of) redundancy in multimedia • data redundancy • how information is represented • some formats are better than others • information redundancy • how human receives the information • some information is more important than the other

  41. Audio encoding • Surprisingly, audio is hard to compress! • Sampling • Frequency band and sub-bands • Quantization • uniform or non-uniform quantizer, differential • Encoding • Standards: ITU-T G.7xx, MP-3, AAC, etc

  42. Image compression • Transformation • exploit spatial redundancy • Quantization • remove information redundancy • Encoding • remove data redundancy • Standards: JPEG (1993), JPEG2000, etc

  43. Video compression • Video is a sequence of images • there is temporal redundancy between frames • Image compression • transformation, quantization, encoding • Further, for video compression • motion estimation • Standards: MPEG-1/2/4, H.26x, etc

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