Multimedia

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Session No. 7

Multimedia

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Agenda

▪ What is Multimedia ?▪ Multimedia representation

▪ Multimedia processing

▪ Multimedia compression

▪ Multimedia communications

▪ Multimedia applications

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Multimedia – different viewpoints

▪ A PC vendor: a PC that has sound capability, a DVD-ROM drive, and perhaps the superiority of multimedia-enabled microprocessors that understand additional multimedia instructions

▪ A consumer entertainment vendor: interactive cable TV with hundreds of digital channels available, or a cable TV-like service delivered over a high-speed Internet connection

▪ A Computer Science student: applications that use multiple modalities, including text, images, graphics, animation, video, sound including speech, and interactivity

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History of Multimedia

r 1. Newspaper: perhaps the first mass communication medium using text, graphics, and images

r 2. Motion pictures: conceived of in 1830's in order to observe motion too rapid for perception by the human eye

r 3. Wireless radio transmission: Guglielmo Marconi, at Pontecchio, Italy, in 1895

r 4. Television: the new medium for the 20th century, established video as a commonly available medium and has since changed the world of mass communications

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History of Multimedia

r The connection between computers and ideas about multimedia covers what is actually only a short period:m 1945 - Vannevar Bush wrote a landmark article describing what

amounts to a hypermedia system called Memexm 1960 - Ted Nelson coined the term hypertextm 1967 - Nicholas Negroponte formed the Architecture Machine

Group m 1968 - Douglas Engelbart demonstrated the On-Line System

(NLS) another very early hypertext programm 1969- Nelson and van Dam at Brown University created an

early hypertext editor called FRESS

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History of Multimedia

1976 - The MIT Architecture Machine Group proposed a project entitled

1977 Multiple Media | resulted in the Aspen Movie Map, the first

1978 hypermedia videodisk, in 1978r 1985 - Negroponte and Wiesner co-founded the MIT Media

Labr 1989 - Tim Berners-Lee proposed the World Wide Webr 1990 - Kristina Hooper Woolsey headed the Apple

Multimedia Labr 1991 - MPEG-1 was approved as an international standard

for digitalr videor 1991 - The introduction of PDAs in 1991 began a new period

in the use r of computers in multimedia

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History of Multimedia

r 1992 - JPEG was accepted as the international standard for digital image

r compression ; led to the new JPEG2000 standardr 1992 - The first MBone audio multicast on the Net was mader 1993 - The University of Illinois National Center for

Supercomputingr Applications produced NCSA Mosaic, the first full-

edged browserr 1994 - Jim Clark and Marc Andreessen created the Netscape

programr 1995 - The JAVA language was created for platform-independentr application development

1996 - DVD video was introduced; high quality full-length movies were1997 distributed on a single disk

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History of Multimedia

r 1998 - XML 1.0 was announced as a W3C Recommendation1998 - Hand-held MP3 devices first made inroads into

consumerist tastes1999 in the fall of 1998, with the introduction of devices

holding 32MBr of flash memoryr 2000 - WWW size was estimated at over 1 billion pages

………….and multimedia continues to evolve

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Hypermedia and Multimedia

r A hypertext system: meant to be read nonlinearly, by

r following links that point to other parts of the document, or

r to other documents

r HyperMedia: not constrained to be text-based, can include

r other media, e.g., graphics, images, and especially the

r continuous media , sound and video(e.g. the WWW)

r Multimedia means that computer information can be

r represented through audio, graphics, images, video, and

r animation in addition to traditional media

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Hypermedia and Multimedia

Hypertext is non-linear

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Multimedia Representation

r Multimedia content –r text, images, audio, video represented as digital

data

r Data acquisition – using analog-to-digital devices

r • Audio – microphone + audio cardr • Images – picture + scanner, digital cameras,

graphics, imager editorr • Videos - analog camera + video capture card,

digital videor cameras, video editing software,

computer graphicsr rendering

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Multimedia Representation

r Data playback - digital-to-analog devicesr • Audio – speakerphone + audio card, CD player,

MP3 playerr • Images – Computer monitor, printerr • Videos – Computer monitor or TV with Stream

Video,r VCD/DVD, Direct TV

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Multimedia Representation

r Text -r Each character (letters and symbols) is

represented by a fixedr number of bits. In ASCII code ‘A’ is 01000001

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Multimedia Representation

r Image -r • Represented as 2-dimensional signal

r • Arranged in units called pixels

r • The value of each pixel represents the radiance intensity of

r the scene. For color image, there are usually three components,

r e.g. red, green, and blue. Each range from 0 to 255

r • Image compression method can dramatically reduce the size

r of the image data. Some standards include JPEG,JPEG2000

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Multimedia Representation

r Audio –

r • Represented as 1-dimensional

r signal

r • Continuous acoustic wave is

r digitized into a sequence of

r bytes

r • Audio compression method

r is used to reduce the amount

r of data (MP3 e.g. 10:1 ratio)

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Multimedia Representation

r Video -r • Video is represented

asr sequence of images

calledr frames

r • NTSC video has roughly 30

r frames per second

r • Video compression standard

r such as MPEG2(DVD) and

r MPEG4 can significantly

r reduce the size of video

r files

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Multimedia Processing

r Audio - Video -r • Equalization • Change frame rater • Denoise • Blendingr • Voice removal (for karaoke) • stabilization

r Image -r • Negationr • Histogram equalizationr • Denoiser • Deblur/Sharpen/Edge enhancement … and many

morer

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Multimedia Compression

r How does compression work ?r Assume that we have 4 letters in a language viz. “A” “B”

“S” “Z”

r To uniquely encode each letter, let us assign two bits each :

r A-00, B-01, S-10, Z – 11. Message “AAABSAAAAZ” is encoded with 20 bits

r Now let us assign:A- 0, B-100, S-101, Z – 111. The same message can be encoded using 16 bits

r The basic idea behind data compression – assign shorter codeword to more frequently used symbols

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Multimedia Compression Standards

▪ In order to enable communication between different media source

▪ compression standards are established

▪ Audio – Differential pulse code modulation (DPCM), adaptive predictive coding (APC), linear predictive coding (LPC), MPEG audio coders (e.g MP3)

▪ Image – Graphics interchange format (GIF), Joint- Photographic Experts Group (JPEG 10:1 to 20:1), JPEG-2000

▪ Video – Moving JPEG (MJPEG), ITU-T H.261, H.263, Motion Picture Expert Group (MPEG-1, MPEG-2, MPEG-4)

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Multimedia Communications

r Interpersonal applications -r Circuit-mode networks – physical connection, constant bit

rate per channelr Packet-switched networks – virtual connection, packets

are transmitted in a shared networkr Interaction over the Internet -r Information browsing (Web servers and browsers)r Electronic commence (information travel in both

directions)r Entertainment -r Movie/Video-on-demandr Interactive television

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Multimedia Applications

▪ Digital video editing and production systems▪ Electronic newspapers/magazines▪ World Wide Web▪ On-line reference works: e.g. encyclopedias, games,

etc▪ Home shopping▪ Interactive TV▪ Multimedia courseware▪ Video conferencing▪ Video-on-demand▪ Interactive movies▪ Live camera – surveillance, traffic monitoring

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Overview of Multimedia Software Toolsr The categories of software tools briefly examined

here are:

r 1. Music Sequencing and Notationr 2. Digital Audior 3. Graphics and Image Editingr 4. Video Editingr 5. Animationr 6. Multimedia Authoring

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Music Sequencing and Notation

r Cakewalk: now called Pro Audior Allows to insert WAV files and Windows MCI

commandsr (for animation and video) into music tracks

r Cubase: Capabilities similar to those of Cakewalk. It includes

r some digital audio editing tools

r Macromedia SoundEdit: Program for creating audio for

r multimedia projects and the web; integrates with other

r Macromedia products such as Flash and Director

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Digital Audio

r Cool Edit: emulates a professional audio studio - multi-track

r productions and sound file editing including digital signal

r processing effects

r Sound Forge: a sophisticated PC-based program for editing

r audio WAV files

r Pro Tools: a high-end integrated audio production and editing

r environment - MIDI creation and manipulation; powerful audio

r mixing, recording, and editing software

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Graphics and Image Editing

r Adobe Illustrator: a powerful publishing tool that uses vector

r graphics; graphics can be exported to Webr Adobe Photoshop: a graphics and image processing

tool r Macromedia Fireworks: software for making graphics

for the webr Macromedia Freehand: a text and web graphics

editing toolr that supports many bitmap formats such as GIF, PNG

and JPEG

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Video Editing

r Adobe Premiere: a simple video editing tool for puttingr video clips into any orderr Adobe After Effects: a video editing tool that enables

users to add and change existing movies.r Can add many effects:r lighting, shadows, motion blurring; layers

r Final Cut Pro: a video editing tool by Apple; Macintosh only

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Rendering Tools

r 3D Studio Max: includes a number of very high-end professional

r tools for animation, game development, and visual effectsr Softimage XSI: a powerful modeling, animation, and

renderingr package used for animation and special effects in films

and gamesr Maya: competing product to Softimage; as well, it is a

completer modeling packager RenderMan: rendering package created by Pixar

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Authoring Tools

r Macromedia Flash: allows users to create interactive movies

r using the score metaphor, i.e., a timeline arranged in parallel

r event sequences

r Macromedia Director: uses a movie metaphor to create

r interactive presentations - very powerful and includes a built-

r in scripting language, Lingo

r Authorware: a mature, well-supported authoring product

r based on the Iconic/Flow-control metaphor

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Multimedia API’s

r Java3D: API used by Java to construct and render 3D graphics,

r similar to the way in which the Java Media Framework is used

r for handling media files

r DirectX : Windows API that supports video, images, audio and

r 3-D animation

r OpenGL: the highly portable, most popular 3-D API

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Thanks for your attention !!!