MUTIMEDIA TECHNOLOGIES Teacher Faraz khan 1222020 1 LECTURE

MUTIMEDIA TECHNOLOGIES Teacher: Faraz khan 12/2/2020 1

LECTURE 1 Introduction, History, Terminologies and Applications 12/2/2020 2

Introduction to Multimedia First consider what constitutes media. Some examples of media are: Ỗ Animation Ỗ Sound Ỗ Graphics Ỗ Text Ỗ Video Ỗ Photography 12/2/2020 3

Technologies n n n Hardware Software Storage Bandwidth Devices Formats and compressions 12/2/2020 4

Introduction to Multimedia involves the combination of two or more media types to effectively create a sequence of events that will communicate an idea usually with both sound and visual support. Typically, multimedia productions are developed and controlled by computer. The enabling force behind multimedia is digital technology. Multimedia today represents the convergence of digital control and digital media - the PC as the digital control system and the digital media being today's most advanced forms of audio and video storage and transmission. 12/2/2020 5

Introduction to Multimedia n Multimedia = "Multiple" + "media" combination of text, image, computer graphics, animation, sound, and video. q Inveractive Multimedia - allow user to control each media q q 12/2/2020 Multimedia is the field concerned with the computer-controlled integration of text, graphics, drawings, still and moving images (Video), animation, audio, and any other media where every type of information can be represented, stored, transmitted and processed digitally. 6

Introduction to Multimedia System What is a multimedia system? multimedia system supports the integrated storage, transmission and representation of the discrete media types text, graphics and image and the continuous media types audio and video on a digital computer. A Text, . . Speech, Audio Animation (Still Image) 12/2/2020 Digitalize Playback Video Interactive 7

History of Multimedia Systems Newspaper were perhaps the first mass communication medium to employ Multimedia, they used mostly text, graphics, and images. In 1895, Gugliemo Marconi sent his first wireless radio transmission at Pontecchio, Italy. A few years later (in 1901) he detected radio waves beamed across the Atlantic. Initially invented for telegraph, radio is now a major medium for audio broadcasting. Television was the new media for the 20 th century. 12/2/2020 8

What is Hyper. Text and Hyper. Media? Hypertext is a text which contains links to other texts. The term was invented by Ted Nelson around 1965. Hypertext is therefore usually non-linear (as indicated below). 12/2/2020 10

Definition of Hypermedia can include other media, e. g. , graphics, images, and especially the continuous media - sound and video. Apparently, Ted Nelson was also the first to use this term. The World Wide Web (WWW) is the best example of hypermedia applications 12/2/2020 11

Characteristics of a Multimedia System A Multimedia system has four basic characteristics: Ỗ Multimedia systems must be computer controlled. Ỗ Multimedia systems are integrated. Ỗ The information they handle must be represented digitally. Ỗ The interface to the final presentation of media is usually interactive 12/2/2020 12

Challenges for Multimedia Systems Multimedia systems may have to render a variety of media at the same instant -- a distinction from normal applications. There is a temporal relationship between many forms of media (e. g. Video and Audio) There are 2 forms of problems here Sequencing within the media : Playing frames in correct order/time frame in video Synchronization inter-media scheduling (e. g. Video and Audio). Lip synchronization is clearly important for humans to watch playback of video and audio and even animation and audio. 12/2/2020 13

The key issues multimedia systems Ỗ How to represent and store temporal information? Ỗ How to strictly maintain the temporal relationships on play back/retrieval? Ỗ What process are involved in the above? Ỗ Data has to represented digitally so many initial source of data needs to be digitise -- translated from analog source to digital representation. They will involve scanning (graphics, still images), sampling (audio/video) although digital cameras now exist for direct scene to digital capture of images and video. Ỗ The data is large several Mb easily for audio and video – therefore storage, transfer (bandwidth) and processing overheads are high. Data compression techniques very common. 12/2/2020 14

Desirable Features for a Multimedia System Given the above challenges the following feature a desirable (if not a prerequisite) for a Multimedia System: Very High Processing Power Needed to deal with large data processing and real time delivery of media. Special hardware commonplace. Multimedia Capable File System Needed to deliver real-time media -- e. g. Video/Audio Streaming. Special Hardware/Software needed e. g RAID technology. Data Representations/File Formats that support multimedia Data representations/file formats should be easy to handle yet allow for compression/decompression in real-time. 12/2/2020 15

Efficient and High I/O Input and output to the file subsystem needs to be efficient and fast. Needs to allow for real-time recording as well as playback of data. e. g. Direct to Disk recording systems. Special Operating System To allow access to file system and process data efficiently and quickly. Needs to support direct transfers to disk, real-time scheduling, fast interrupt processing, I/O streaming etc. Storage and Memory Large storage units (of the order of 50 -100 Gb or more) and large memory (50 -100 Mb or more). Large Caches also required and frequently of Level 2 and 3 hierarchy for efficient management. Network Support Client-server systems common as distributed systems common. Software Tools User friendly tools needed to handle media, design and develop applications, deliver media. 12/2/2020 16

Components of a Multimedia System Capture devices Video Camera, Video Recorder, Audio Microphone, Keyboards, mice, graphics tablets, 3 D input devices, tactile sensors, VR devices. Digitising/Sampling Hardware Storage Devices Hard disks, CD-ROMs, Jaz/Zip drives, DVD, etc Communication Networks Ethernet, Token Ring, FDDI, ATM, Intranets, Internets. Computer Systems Multimedia Desktop machines, Workstations, MPEG/VIDEO/DSP Hardware Display Devices CD-quality speakers, HDTV, SVGA, Hi-Resolution monitors, Color printers etc. 12/2/2020 17

Applications Ỗ World Wide Web Ỗ Hypermedia courseware Ỗ Video conferencing Ỗ Video-on-demand Ỗ Interactive TV Ỗ Groupware Ỗ Home shopping Ỗ Games Ỗ Virtual reality Ỗ Digital video editing and production systems Ỗ Multimedia Database systems 12/2/2020 18

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