Multimedia Systems: Storage Devices, Output Devices, and Synchronization, Exercises of Communication

Download Multimedia Systems: Storage Devices, Output Devices, and Synchronization and more Exercises Communication in PDF only on Docsity! Multimedia Systems- M.Sc(IT) 1 UNIT - I Lesson 1 Introduction to Multimedia Contents 1.0 Aims and Objectives 1.1 Introduction 1.2 Elements of Multimedia System 1.3 Categories of Multimedia. 1.4 Features of Multimedia 1.5 Applications of Multimedia System. 1.6 Convergence of Multimedia System. 1.7 Stages of Multimedia Application Development 1.8 Let us sum up. 1.9 Lesson-end activities 1.10 Model answers to “Check your progress” 1.11 References 1.0 Aims and Objectives In this lesson we will learn the preliminary concepts of Multimedia. We will discuss the various benefits and applications of multimedia. After going through this chapter the reader will be able to : i) define multimedia ii) list the elements of multimedia iii) enumerate the different applications of multimedia iv) describe the different stages of multimedia software development 1.1 Introduction Multimedia has become an inevitable part of any presentation. It has found a variety of applications right from entertainment to education. The evolution of internet has also increased the demand for multimedia content. Definition Multimedia is the media that uses multiple forms of information content and information processing (e.g. text, audio, graphics, animation, video, interactivity) to inform or entertain the user. Multimedia also refers to the use of electronic media to store and experience multimedia content. Multimedia is similar to traditional mixed media in fine art, but with a broader scope. The term "rich media" is synonymous for interactive multimedia. Multimedia Systems- M.Sc(IT) 2 1.2 Elements of Multimedia System Multimedia means that computer information can be represented through audio, graphics, image, video and animation in addition to traditional media(text and graphics). Hypermedia can be considered as one type of particular multimedia application. Multimedia is a combination of content forms: Audio http://en.wikipedia.org/wiki/Image:Crystal_Clear_app_aktion.png http://en.wikipedia.org/wiki/Image:Crystal_Clear_app_camera.png http://en.wikipedia.org/wiki/Image:Crystal_Clear_app_mouse.png Video Multimedia Systems- M.Sc(IT) 5 Entertainment and Fine Arts In addition, multimedia is heavily used in the entertainment industry, especially to develop special effects in movies and animations. Multimedia games are a popular pastime and are software programs available either as CD-ROMs or online. Some video games also use multimedia features. Multimedia applications that allow users to actively participate instead of just sitting by as passive recipients of information are called Interactive Multimedia. Education In Education, multimedia is used to produce computer-based training courses (popularly called CBTs) and reference books like encyclopaedia and almanacs. A CBT lets the user go through a series of presentations, text about a particular topic, and associated illustrations in various information formats. Edutainment is an informal term used to describe combining education with entertainment, especially multimedia entertainment. Engineering Software engineers may use multimedia in Computer Simulations for anything from entertainment to training such as military or industrial training. Multimedia for software interfaces are often done as collaboration between creative professionals and software engineers. Industry In the Industrial sector, multimedia is used as a way to help present information to shareholders, superiors and coworkers. Multimedia is also helpful for providing employee training, advertising and selling products all over the world via virtually unlimited web-based technologies. Mathematical and Scientific Research In Mathematical and Scientific Research, multimedia is mainly used for modeling and simulation. For example, a scientist can look at a molecular model of a particular substance and manipulate it to arrive at a new substance. Representative research can be found in journals such as the Journal of Multimedia. Medicine In Medicine, doctors can get trained by looking at a virtual surgery or they can simulate how the human body is affected by diseases spread by viruses and bacteria and then develop techniques to prevent it. Multimedia Systems- M.Sc(IT) 6 Multimedia in Public Places In hotels, railway stations, shopping malls, museums, and grocery stores, multimedia will become available at stand-alone terminals or kiosks to provide information and help. Such installation reduce demand on traditional information booths and personnel, add value, and they can work around the clock, even in the middle of the night, when live help is off duty. A menu screen from a supermarket kiosk that provide services ranging from meal planning to coupons. Hotel kiosk list nearby restaurant, maps of the city, airline schedules, and provide guest services such as automated checkout. Printers are often attached so users can walk away with a printed copy of the information. Museum kiosk are not only used to guide patrons through the exhibits, but when installed at each exhibit, provide great added depth, allowing visitors to browser though richly detailed information specific to that display. Check Your Progress 1 List five applications of multimedia Notes: a) Write your answers in the space given below. b) Check your answers with the one given at the end of this lesson. …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… 1.6 Convergence of Multimedia (Virtual Reality) At the convergence of technology and creative invention in multimedia is virtual reality, or VR. Goggles, helmets, special gloves, and bizarre human interfaces attempt to place you “inside” a lifelike experience. Take a step forward, and the view gets closer, turn your head, and the view rotates. Reach out and grab an object; your hand moves in front of you. Maybe the object explodes in a 90-decibel crescendo as you wrap your fingers around it. Or it slips out from your grip, falls to the floor, and hurriedly escapes through a mouse hole at the bottom of the wall. VR requires terrific computing horsepower to be realistic. In VR, your cyberspace is made up of many thousands of geometric objects plotted in three-dimensional space: the more objects and the more points that describe the objects, the higher resolution and the more realistic your view. As the user moves about, each motion or action requires the computer to recalculate the position, angle size, and shape of all the objects that make up your view, and many thousands of computations must occur as fast as 30 times per second to seem smooth. Multimedia Systems- M.Sc(IT) 7 On the World Wide Web, standards for transmitting virtual reality worlds or “scenes” in VRML (Virtual Reality Modeling Language) documents (with the file name extension .wrl) have been developed. Using high-speed dedicated computers, multi-million-dollar flight simulators built by singer, RediFusion, and others have led the way in commercial application of VR.Pilots of F-16s, Boeing 777s, and Rockwell space shuttles have made many dry runs before doing the real thing. At the California Maritime academy and other merchant marine officer training schools, computer-controlled simulators teach the intricate loading and unloading of oil tankers and container ships. Specialized public game arcades have been built recently to offer VR combat and flying experiences for a price. From virtual World Entertainment in walnut Greek, California, and Chicago, for example, BattleTech is a ten-minute interactive video encounter with hostile robots. You compete against others, perhaps your friends, who share coaches in the same containment Bay. The computer keeps score in a fast and sweaty firefight. Similar “attractions” will bring VR to the public, particularly a youthful public, with increasing presence during the 1990s. The technology and methods for working with three-dimensional images and for animating them are discussed. VR is an extension of multimedia-it uses the basic multimedia elements of imagery, sound, and animation. Because it requires instrumented feedback from a wired-up person, VR is perhaps interactive multimedia at its fullest extension. 1.7 Stages of Multimedia Application Development A Multimedia application is developed in stages as all other software are being developed. In multimedia application development a few stages have to complete before other stages being, and some stages may be skipped or combined with other stages. Following are the four basic stages of multimedia project development : 1. Planning and Costing : This stage of multimedia application is the first stage which begins with an idea or need. This idea can be further refined by outlining its messages and objectives. Before starting to develop the multimedia project, it is necessary to plan what writing skills, graphic art, music, video and other multimedia expertise will be required. It is also necessary to estimate the time needed to prepare all elements of multimedia and prepare a budget accordingly. After preparing a budget, a prototype or proof of concept can be developed. 2. Designing and Producing : The next stage is to execute each of the planned tasks and create a finished product. 3. Testing : Testing a project ensure the product to be free from bugs. Apart from bug elimination another aspect of testing is to ensure that the multimedia Multimedia Systems- M.Sc(IT) 10 2. Audio : Sound is perhaps the most element of multimedia. It can provide the listening pleasure of music, the startling accent of special effects or the ambience of a mood-setting background. 3. Images : Images whether represented analog or digital plays a vital role in a multimedia. It is expressed in the form of still picture, painting or a photograph taken through a digital camera. 4. Animation : Animation is the rapid display of a sequence of images of 2-D artwork or model positions in order to create an illusion of movement. It is an optical illusion of motion due to the phenomenon of persistence of vision, and can be created and demonstrated in a number of ways. 5. Video : Digital video has supplanted analog video as the method of choice for making video for multimedia use. Video in multimedia are used to portray real time moving pictures in a multimedia project. 2.3 Text in Multimedia Words and symbols in any form, spoken or written, are the most common system of communication. They deliver the most widely understood meaning to the greatest number of people. Most academic related text such as journals, e-magazines are available in the Web Browser readable form. 2.4 About Fonts and Faces A typeface is family of graphic characters that usually includes many type sizes and styles. A font is a collection of characters of a single size and style belonging to a particular typeface family. Typical font styles are bold face and italic. Other style attributes such as underlining and outlining of characters, may be added at the users choice. The size of a text is usually measured in points. One point is approximately 1/72 of an inch i.e. 0.0138. The size of a font does not exactly describe the height or width of its characters. This is because the x-height (the height of lower case character x) of two fonts may differ. Typefaces of fonts can be described in many ways, but the most common characterization of a typeface is serif and sans serif. The serif is the little decoration at the end of a letter stroke. Times, Times New Roman, Bookman are some fonts which comes under serif category. Arial, Optima, Verdana are some examples of sans serif font. Serif fonts are generally used for body of the text for better readability and sans serif fonts are generally used for headings. The following fonts shows a few categories of serif and sans serif fonts. Multimedia Systems- M.Sc(IT) 11 F F (Serif Font) (Sans serif font) Selecting Text fonts It is a very difficult process to choose the fonts to be used in a multimedia presentation. Following are a few guidelines which help to choose a font in a multimedia presentation.  As many number of type faces can be used in a single presentation, this concept of using many fonts in a single page is called ransom-note topography.  For small type, it is advisable to use the most legible font.  In large size headlines, the kerning (spacing between the letters) can be adjusted  In text blocks, the leading for the most pleasing line can be adjusted.  Drop caps and initial caps can be used to accent the words.  The different effects and colors of a font can be chosen in order to make the text look in a distinct manner.  Anti aliased can be used to make a text look gentle and blended.  For special attention to the text the words can be wrapped onto a sphere or bent like a wave.  Meaningful words and phrases can be used for links and menu items.  In case of text links(anchors) on web pages the messages can be accented. The most important text in a web page such as menu can be put in the top 320 pixels. Check Your Progress 1 List a few fonts available in your computer. Notes: a) Write your answers in the space given below. b) Check your answers with the one given at the end of this lesson. …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… Multimedia Systems- M.Sc(IT) 12 2.5 Computers and text: Fonts : Postscript fonts are a method of describing an image in terms of mathematical constructs (Bezier curves), so it is used not only to describe the individual characters of a font but also to describe illustrations and whole pages of text. Since postscript makes use of mathematical formula, it can be easily scaled bigger or smaller. Apple and Microsoft announced a joint effort to develop a better and faster quadratic curves outline font methodology, called truetype In addition to printing smooth characters on printers, TrueType would draw characters to a low resolution (72 dpi or 96 dpi) monitor. 2.6 Character set and alphabets: ASCII Character set The American standard code for information interchange (SCII) is the 7 bit character coding system most commonly used by computer systems in the United states and abroad. ASCII assigns a number of value to 128 characters, including both lower and uppercase letters, punctuation marks, Arabic numbers and math symbols. 32 control characters are also included. These control characters are used for device control messages, such as carriage return, line feed, tab and form feed. The Extended Character set A byte which consists of 8 bits, is the most commonly used building block for computer processing. ASCII uses only 7 bits to code is 128 characters; the 8th bit of the byte is unused. This extra bit allows another 128 characters to be encoded before the byte is used up, and computer systems today use these extra 128 values for an extended character set. The extended character set is commonly filled with ANSI (American National Standards Institute) standard characters, including frequently used symbols. Unicode Unicode makes use of 16-bit architecture for multilingual text and character encoding. Unicode uses about 65,000 characters from all known languages and alphabets in the world. Several languages share a set of symbols that have a historically related derivation, the shared symbols of each language are unified into collections of Multimedia Systems- M.Sc(IT) 15 . 2.10 Model answers to “Check your progress” 1. Your answers may include the following Arial Times New Roman Garamond Script Courier Georgia Book Antiqua Century Gothic 2. Your answer may include the following a) Fontmonger b) Cool 3D text 2.11 References 1. "Multimedia:Concepts and Practice" By Stephen McGloughlin 2. ”Multimedia Computing, Communication and application” By Steinmetz and Klara Nahrstedt. 3. “Multimedia Making it work” By Tay Vaughan 4. “Multimedia in Practice – Technology and applications” By Jeffcoat Multimedia Systems- M.Sc(IT) 16 Lesson 3 Audio Contents 3.0 Aims and Objectives 3.1 Introduction 3.2 Power of Sound 3.3 Multimedia Sound Systems 3.4 Digital Audio 3.5 Editing Digital Recordings 3.6 Making MIDI Audio 3.7 Audio File Formats 3.8 Red Book Standard 3.9 Software used for Audio 3.10 Let us sum up 3.11 Lesson-end activities 3.12 Model answers to “Check your progress” 3.13 References 3.0 Aims and Objectives In this lesson we will learn the basics of Audio. We will learn how a digital audio is prepared and embedded in a multimedia system. At the end of the chapter the learner will be able to : i) Distinguish audio and sound ii) Prepare audio required for a multimedia system iii) The learner will be able to list the different audio editing softwares. iv) List the different audio file formats 3.1 Introduction Sound is perhaps the most important element of multimedia. It is meaningful “speech” in any language, from a whisper to a scream. It can provide the listening pleasure of music, the startling accent of special effects or the ambience of a mood- setting background. Sound is the terminology used in the analog form, and the digitized form of sound is called as audio. Multimedia Systems- M.Sc(IT) 17 3.2 Power of Sound When something vibrates in the air is moving back and forth it creates wave of pressure. These waves spread like ripples from pebble tossed into a still pool and when it reaches the eardrums, the change of pressure or vibration is experienced as sound. Acoustics is the branch of physics that studies sound. Sound pressure levels are measured in decibels (db); a decibel measurement is actually the ratio between a chosen reference point on a logarithmic scale and the level that is actually experienced. 3.3 Multimedia Sound Systems The multimedia application user can use sound right off the bat on both the Macintosh and on a multimedia PC running Windows because beeps and warning sounds are available as soon as the operating system is installed. On the Macintosh you can choose one of the several sounds for the system alert. In Windows system sounds are WAV files and they reside in the windows\Media subdirectory. There are still more choices of audio if Microsoft Office is installed. Windows makes use of WAV files as the default file format for audio and Macintosh systems use SND as default file format for audio. 3.4 Digital Audio Digital audio is created when a sound wave is converted into numbers – a process referred to as digitizing. It is possible to digitize sound from a microphone, a synthesizer, existing tape recordings, live radio and television broadcasts, and popular CDs. You can digitize sounds from a natural source or prerecorded. Digitized sound is sampled sound. Ever nth fraction of a second, a sample of sound is taken and stored as digital information in bits and bytes. The quality of this digital recording depends upon how often the samples are taken. 3.4.1 Preparing Digital Audio Files Preparing digital audio files is fairly straight forward. If you have analog source materials – music or sound effects that you have recorded on analog media such as cassette tapes.  The first step is to digitize the analog material and recording it onto a computer readable digital media.  It is necessary to focus on two crucial aspects of preparing digital audio files: o Balancing the need for sound quality against your available RAM and Hard disk resources. o Setting proper recording levels to get a good, clean recording. Multimedia Systems- M.Sc(IT) 20 A digital audio file format is preferred in the following circumstances:  When there is no control over the playback hardware  When the computing resources and the bandwidth requirements are high.  When dialogue is required. 3.7 Audio File Formats A file format determines the application that is to be used for opening a file. Following is the list of different file formats and the software that can be used for opening a specific file. 1. *.AIF, *.SDII in Macintosh Systems 2. *.SND for Macintosh Systems 3. *.WAV for Windows Systems 4. MIDI files – used by north Macintosh and Windows 5. *.WMA –windows media player 6. *.MP3 – MP3 audio 7. *.RA – Real Player 8. *.VOC – VOC Sound 9. AIFF sound format for Macintosh sound files 10. *.OGG – Ogg Vorbis 3.8 Red Book Standard The method for digitally encoding the high quality stereo of the consumer CD music market is an instrument standard, ISO 10149. This is also called as RED BOOK standard. The developers of this standard claim that the digital audio sample size and sample rate of red book audio allow accurate reproduction of all sounds that humans can hear. The red book standard recommends audio recorded at a sample size of 16 bits and sampling rate of 44.1 KHz. Check Your Progress 2 Write the specifications used in red book standard Notes: a) Write your answers in the space given below. b) Check your answers with the one given at the end of this lesson. …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… Multimedia Systems- M.Sc(IT) 21 3.9 Software used for Audio Software such as Toast and CD-Creator from Adaptec can translate the digital files of red book Audio format on consumer compact discs directly into a digital sound editing file, or decompress MP3 files into CD-Audio. There are several tools available for recording audio. Following is the list of different software that can be used for recording and editing audio ;  Soundrecorder from Microsoft  Apple’s QuickTime Player pro  Sonic Foundry’s SoundForge for Windows  Soundedit16 3.10 Let us sum up Following points have been discussed in this lesson:  Audio is an important component of multimedia which can be used to provide liveliness to a multimedia presentation.  The red book standard recommends audio recorded at a sample size of 16 bits and sampling rate of 44.1 KHz.  MIDI is Musical Instrument Digital Interface.  MIDI is a communication standard developed for electronic musical instruments and computers.  To make MIDI scores, however you will need sequencer software and a sound synthesizer 3.11 Lesson-end activities Record an audio clip using sound recorder in Microsoft Windows for 1 minute. Note down the size of the file. Using any audio compression software convert the recorded file to MP3 format and compare the size of the audio. 3.12 Model answers to “Check your progress” 1. Audio editing includes the following:  Multiple Tasks  Trimming  Splicing and Assembly  Volume Adjustments  Format Conversion  Resampling or downsampling  Equalization Multimedia Systems- M.Sc(IT) 22  Digital Signal Processing  Reversing Sounds  Time Stretching 2. The red book standard recommends audio recorded at a sample size of 16 bits and sampling rate of 44.1 KHz. The recording is done with 2 channels(stereo mode). 3.13 References 1. “Multimedia Making it work” By Tay Vaughan 2. ”Multimedia Computing, Communication and application” By Steinmetz and Klara Nahrstedt. Multimedia Systems- M.Sc(IT) 25 Where do bitmap come from? How are they made?  Make a bitmap from scratch with paint or drawing program.  Grab a bitmap from an active computer screen with a screen capture program, and then paste into a paint program or your application.  Capture a bitmap from a photo, artwork, or a television image using a scanner or video capture device that digitizes the image. Once made, a bitmap can be copied, altered, e-mailed, and otherwise used in many creative ways. Clip Art A clip art collection may contain a random assortment of images, or it may contain a series of graphics, photographs, sound, and video related to a single topic. For example, Corel, Micrografx, and Fractal Design bundle extensive clip art collection with their image-editing software. Multiple Monitors When developing multimedia, it is helpful to have more than one monitor, or a single high-resolution monitor with lots of screen real estate, hooked up to your computer. In this way, you can display the full-screen working area of your project or presentation and still have space to put your tools and other menus. This is particularly important in an authoring system such as Macromedia Director, where the edits and changes you make in one window are immediately visible in the presentation window-provided the presentation window is not obscured by your editing tools. Check Your Progress 1 List a few software that can be used for creating images. Notes: a) Write your answers in the space given below. b) Check your answers with the one given at the end of this lesson. …………………………………………………………………………… …………………………………………………………………………… 1-bit bitmap 2 colors 4-bit bitmap 16 colors 8-bit bitmap 256 colors Multimedia Systems- M.Sc(IT) 26 4.4 Making Still Images Still images may be small or large, or even full screen. Whatever their form, still images are generated by the computer in two ways: as bitmap (or paint graphics) and as vector-drawn (or just plain drawn) graphics. Bitmaps are used for photo-realistic images and for complex drawing requiring fine detail. Vector-drawn objects are used for lines, boxes, circles, polygons, and other graphic shapes that can be mathematically expressed in angles, coordinates, and distances. A drawn object can be filled with color and patterns, and you can select it as a single object. Typically, image files are compressed to save memory and disk space; many image formats already use compression within the file itself – for example, GIF, JPEG, and PNG. Still images may be the most important element of your multimedia project. If you are designing multimedia by yourself, put yourself in the role of graphic artist and layout designer. 4.4.1 Bitmap Software The abilities and feature of image-editing programs for both the Macintosh and Windows range from simple to complex. The Macintosh does not ship with a painting tool, and Windows provides only the rudimentary Paint (see following figure), so you will need to acquire this very important software separately – often bitmap editing or painting programs come as part of a bundle when you purchase your computer, monitor, or scanner. Figure: The Windows Paint accessory provides rudimentary bitmap editing Multimedia Systems- M.Sc(IT) 27 4.4.2 Capturing and Editing Images The image that is seen on a computer monitor is digital bitmap stored in video memory, updated about every 1/60 second or faster, depending upon monitor’s scan rate. When the images are assembled for multimedia project, it may often be needed to capture and store an image directly from screen. It is possible to use the Prt Scr key available in the keyboard to capture a image. Scanning Images After scanning through countless clip art collections, if it is not possible to find the unusual background you want for a screen about gardening. Sometimes when you search for something too hard, you don’t realize that it’s right in front of your face. Open the scan in an image-editing program and experiment with different filters, the contrast, and various special effects. Be creative, and don’t be afraid to try strange combinations – sometimes mistakes yield the most intriguing results. 4.5 Vector Drawing Most multimedia authoring systems provide for use of vector-drawn objects such as lines, rectangles, ovals, polygons, and text. Computer-aided design (CAD) programs have traditionally used vector-drawn object systems for creating the highly complex and geometric rendering needed by architects and engineers. Graphic artists designing for print media use vector-drawn objects because the same mathematics that put a rectangle on your screen can also place that rectangle on paper without jaggies. This requires the higher resolution of the printer, using a page description language such as PostScript. Programs for 3-D animation also use vector-drawn graphics. For example, the various changes of position, rotation, and shading of light required to spin the extruded. How Vector Drawing Works Vector-drawn objects are described and drawn to the computer screen using a fraction of the memory space required to describe and store the same object in bitmap form. A vector is a line that is described by the location of its two endpoints. A simple rectangle, for example, might be defined as follows: RECT 0,0,200,200 Multimedia Systems- M.Sc(IT) 30 2. In additive color model, a color is created by combining colored lights sources in three primary colors: red, green and blue (RGB). This is the process used for a TV or computer monitor. In subtractive color method, a new color is created by subtracting colors from , cyan, magenta and yellow (CMY). Subtractive color is the process used to create color in printing. 4.11 References 1. “Multimedia Making it work” By Tay Vaughan 2. “Multimedia in Practice – Technology and applications” By Jeffcoat Multimedia Systems- M.Sc(IT) 31 Lesson 5 Animation and Video Contents 5.0 Aims and Objectives 5.1 Introduction 5.2 Principles of Animation 5.3 Animation Techniques 5.4 Animation File formats 5.5 Video 5.6 Broadcast video Standard 5.7 Shooting and editing video 5.8 Video Compression 5.9 Let us sum up 5.10 Lesson-end activities 5.11 Model answers to “Check your progress” 5.12 References 5.0 Aims and Objectives In this lesson we will learn the basics of animation and video. At the end of this lesson the learner will be able to i) List the different animation techniques. ii) Enumerate the software used for animation. iii) List the different broadcasting standards. iv) Describe the basics of video recording and how they relate to multimedia production. v) Have a knowledge on different video formats. 5.1 Introduction Animation makes static presentations come alive. It is visual change over time and can add great power to our multimedia projects. Carefully planned, well-executed video clips can make a dramatic difference in a multimedia project. Animation is created from drawn pictures and video is created using real time visuals. 5.2 Principles of Animation Animation is the rapid display of a sequence of images of 2-D artwork or model positions in order to create an illusion of movement. It is an optical illusion of motion due to the phenomenon of persistence of vision, and can be created and demonstrated in a number of ways. The most common method of presenting animation is as a motion picture or video program, although several other forms of presenting animation also exist Multimedia Systems- M.Sc(IT) 32 Animation is possible because of a biological phenomenon known as persistence of vision and a psychological phenomenon called phi. An object seen by the human eye remains chemically mapped on the eye’s retina for a brief time after viewing. Combined with the human mind’s need to conceptually complete a perceived action, this makes it possible for a series of images that are changed very slightly and very rapidly, one after the other, to seemingly blend together into a visual illusion of movement. The following shows a few cells or frames of a rotating logo. When the images are progressively and rapidly changed, the arrow of the compass is perceived to be spinning. Television video builds entire frames or pictures every second; the speed with which each frame is replaced by the next one makes the images appear to blend smoothly into movement. To make an object travel across the screen while it changes its shape, just change the shape and also move or translate it a few pixels for each frame. 5.3 Animation Techniques When you create an animation, organize its execution into a series of logical steps. First, gather up in your mind all the activities you wish to provide in the animation; if it is complicated, you may wish to create a written script with a list of activities and required objects. Choose the animation tool best suited for the job. Then build and tweak your sequences; experiment with lighting effects. Allow plenty of time for this phase when you are experimenting and testing. Finally, post-process your animation, doing any special rendering and adding sound effects. 5.3.1 Cel Animation The term cel derives from the clear celluloid sheets that were used for drawing each frame, which have been replaced today by acetate or plastic. Cels of famous animated cartoons have become sought-after, suitable-for-framing collector’s items. Cel animation artwork begins with keyframes (the first and last frame of an action). For example, when an animated figure of a man walks across the screen, he balances the weight of his entire body on one foot and then the other in a series of falls and recoveries, with the opposite foot and leg catching up to support the body.  The animation techniques made famous by Disney use a series of progressively different on each frame of movie film which plays at 24 frames per second. Multimedia Systems- M.Sc(IT) 35 5.5 Video Analog versus Digital Digital video has supplanted analog video as the method of choice for making video for multimedia use. While broadcast stations and professional production and post- production houses remain greatly invested in analog video hardware (according to Sony, there are more than 350,000 Betacam SP devices in use today), digital video gear produces excellent finished products at a fraction of the cost of analog. A digital camcorder directly connected to a computer workstation eliminates the image-degrading analog-to-digital conversion step typically performed by expensive video capture cards, and brings the power of nonlinear video editing and production to everyday users. 5.6 Broadcast Video Standards Four broadcast and video standards and recording formats are commonly in use around the world: NTSC, PAL, SECAM, and HDTV. Because these standards and formats are not easily interchangeable, it is important to know where your multimedia project will be used. NTSC The United States, Japan, and many other countries use a system for broadcasting and displaying video that is based upon the specifications set forth by the 1952 National Television Standards Committee. These standards define a method for encoding information into the electronic signal that ultimately creates a television picture. As specified by the NTSC standard, a single frame of video is made up of 525 horizontal scan lines drawn onto the inside face of a phosphor-coated picture tube every 1/30th of a second by a fast-moving electron beam. PAL The Phase Alternate Line (PAL) system is used in the United Kingdom, Europe, Australia, and South Africa. PAL is an integrated method of adding color to a black-and-white television signal that paints 625 lines at a frame rate 25 frames per second. SECAM The Sequential Color and Memory (SECAM) system is used in France, Russia, and few other countries. Although SECAM is a 625-line, 50 Hz system, it differs greatly from both the NTSC and the PAL color systems in its basic technology and broadcast method. Multimedia Systems- M.Sc(IT) 36 HDTV High Definition Television (HDTV) provides high resolution in a 16:9 aspect ratio (see following Figure). This aspect ratio allows the viewing of Cinemascope and Panavision movies. There is contention between the broadcast and computer industries about whether to use interlacing or progressive-scan technologies. Check Your Progress 2 List the different broadcast video standards and compare their specifications. Notes: a) Write your answers in the space given below. b) Check your answers with the one given at the end of this lesson. …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… 5.7 Shooting and Editing Video To add full-screen, full-motion video to your multimedia project, you will need to invest in specialized hardware and software or purchase the services of a professional video production studio. In many cases, a professional studio will also provide editing tools and post-production capabilities that you cannot duplicate with your Macintosh or PC. NTSC television overscan approx. 648X480 (4:3) Figure: Difference between VGA and HDTV aspect ratios Monitor 640X480 (4:3) Safe title area 512X384 (4:3) 35mm slide / photo 768X512 (3:2) HDTV 1280X720 (16:9) Multimedia Systems- M.Sc(IT) 37 Video Tips A useful tool easily implemented in most digital video editing applications is “blue screen,” “Ultimate,” or “chromo key” editing. Blue screen is a popular technique for making multimedia titles because expensive sets are not required. Incredible backgrounds can be generated using 3-D modeling and graphic software, and one or more actors, vehicles, or other objects can be neatly layered onto that background. Applications such as VideoShop, Premiere, Final Cut Pro, and iMovie provide this capability. Recording Formats S-VHS video In S-VHS video, color and luminance information are kept on two separate tracks. The result is a definite improvement in picture quality. This standard is also used in Hi-8. still, if your ultimate goal is to have your project accepted by broadcast stations, this would not be the best choice. Component (YUV) In the early 1980s, Sony began to experiment with a new portable professional video format based on Betamax. Panasonic has developed their own standard based on a similar technology, called “MII,” Betacam SP has become the industry standard for professional video field recording. This format may soon be eclipsed by a new digital version called “Digital Betacam.” Digital Video Full integration of motion video on computers eliminates the analog television form of video from the multimedia delivery platform. If a video clip is stored as data on a hard disk, CD-ROM, or other mass-storage device, that clip can be played back on the computer’s monitor without overlay boards, videodisk players, or second monitors. This playback of digital video is accomplished using software architecture such as QuickTime or AVI, a multimedia producer or developer; you may need to convert video source material from its still common analog form (videotape) to a digital form manageable by the end user’s computer system. So an understanding of analog video and some special hardware must remain in your multimedia toolbox. Analog to digital conversion of video can be accomplished using the video overlay hardware described above, or it can be delivered direct to disk using FireWire cables. To repetitively digitize a full-screen color video image every 1/30 second and store it to disk or RAM severely taxes both Macintosh and PC processing capabilities–special hardware, compression firmware, and massive amounts of digital storage space are required. Multimedia Systems- M.Sc(IT) 40 5.10 Lesson-end activities 1. Choose animation software available for windows. List its name and its capabilities. Find whether the software is capable of handling layers? Keyframes? Tweening? Morphing? Check whether the software allows cross platform playback facilities. 2. Locate three web sites that offer streaming video clips. Check the file formats and the duration, size of video. Make a list of software that can play these video clips. 5.11 Model answers to “Check your progress” 1. The different techniques used in animation are cel animation, computer animation, kinematics and morphing. 2. Four broadcast and video standards and recording formats are commonly in use NTSC, PAL, SECAM, and HDTV. 5.12 References 1.”Multimedia Computing, Communication and application” By Steinmetz and Klara Nahrstedt. 2. “Multimedia Making it work” By Tay Vaughan 3. “Multimedia in Practice – Technology and applications” By Jeffcoat 4. http://en.wikipedia.org/wiki/Animation_software Multimedia Systems- M.Sc(IT) 41 UNIT - II Lesson 6 Multimedia Hardware – Connecting Devices Contents 6.0 Aims and Objectives 6.1 Introduction 6.2 Multimedia Hardware 6.3 Connecting Devices 6.4 SCSI 6.5 MCI 6.6 IDE 6.7 USB 6.8 Let us sum up 6.9 Lesson-end activities 6.10 Model answers to “Check your progress” 6.11 References 6.0 Aims and Objectives In this lesson we will learn about the multimedia hardware required for multimedia production. At the end of the lesson the learner will be able to identify the proper hardware required for connecting various devices. 6.1 Introduction The hardware required for multimedia PC depends on the personal preference, budget, project delivery requirements and the type of material and content in the project. Multimedia production was much smoother and easy in Macintosh than in Windows. But Multimedia content production in windows has been made easy with additional storage and less computing cost. Right selection of multimedia hardware results in good quality multimedia presentation. 6.2 Multimedia Hardware The hardware required for multimedia can be classified into five. They are 1. Connecting Devices 2. Input devices 3. Output devices 4. Storage devices and 5. Communicating devices. Multimedia Systems- M.Sc(IT) 42 6.3 Connecting Devices Among the many hardware – computers, monitors, disk drives, video projectors, light valves, video projectors, players, VCRs, mixers, sound speakers there are enough wires which connect these devices. The data transfer speed the connecting devices provide will determine the faster delivery of the multimedia content. The most popularly used connecting devices are:  SCSI  USB  MCI  IDE  USB 6.4 SCSI SCSI (Small Computer System Interface) is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it can connect a wide range of other devices, including scanners, and optical drives (CD, DVD, etc.). SCSI is most commonly pronounced "scuzzy". Since its standardization in 1986, SCSI has been commonly used in the Apple Macintosh and Sun Microsystems computer lines and PC server systems. SCSI has never been popular in the low-priced IBM PC world, owing to the lower cost and adequate performance of its ATA hard disk standard. SCSI drives and even SCSI RAIDs became common in PC workstations for video or audio production, but the appearance of large cheap SATA drives means that SATA is rapidly taking over this market. Currently, SCSI is popular on high-performance workstations and servers. RAIDs on servers almost always use SCSI hard disks, though a number of manufacturers offer SATA-based RAID systems as a cheaper option. Desktop computers and notebooks more typically use the ATA/IDE or the newer SATA interfaces for hard disks, and USB and FireWire connections for external devices. 6.4.1 SCSI interfaces SCSI is available in a variety of interfaces. The first, still very common, was parallel SCSI (also called SPI). It uses a parallel electrical bus design. The traditional SPI design is making a transition to Serial Attached SCSI, which switches to a serial point-to- point design but retains other aspects of the technology. iSCSI drops physical Multimedia Systems- M.Sc(IT) 45 Each device on the SCSI bus is assigned at least one Logical Unit Number (LUN). Simple devices have just one LUN, more complex devices may have multiple LUNs. A "direct access" (i.e. disk type) storage device consists of a number of logical blocks, usually referred to by the term Logical Block Address (LBA). A typical LBA equates to 512 bytes of storage. The usage of LBAs has evolved over time and so four different command variants are provided for reading and writing data. The Read(6) and Write(6) commands contain a 21-bit LBA address. The Read(10), Read(12), Read Long, Write(10), Write(12), and Write Long commands all contain a 32-bit LBA address plus various other parameter options. A "sequential access" (i.e. tape-type) device does not have a specific capacity because it typically depends on the length of the tape, which is not known exactly. Reads and writes on a sequential access device happen at the current position, not at a specific LBA. The block size on sequential access devices can either be fixed or variable, depending on the specific device. (Earlier devices, such as 9-track tape, tended to be fixed block, while later types, such as DAT, almost always supported variable block sizes.) 6.4.4 SCSI device identification In the modern SCSI transport protocols, there is an automated process of "discovery" of the IDs. SSA initiators "walk the loop" to determine what devices are there and then assign each one a 7-bit "hop-count" value. FC-AL initiators use the LIP (Loop Initialization Protocol) to interrogate each device port for its WWN (World Wide Name). For iSCSI, because of the unlimited scope of the (IP) network, the process is quite complicated. These discovery processes occur at power-on/initialization time and also if the bus topology changes later, for example if an extra device is added. On a parallel SCSI bus, a device (e.g. host adapter, disk drive) is identified by a "SCSI ID", which is a number in the range 0-7 on a narrow bus and in the range 0–15 on a wide bus. On earlier models a physical jumper or switch controls the SCSI ID of the initiator (host adapter). On modern host adapters (since about 1997), doing I/O to the adapter sets the SCSI ID; for example, the adapter often contains a BIOS program that runs when the computer boots up and that program has menus that let the operator choose the SCSI ID of the host adapter. Alternatively, the host adapter may come with software that must be installed on the host computer to configure the SCSI ID. The traditional SCSI ID for a host adapter is 7, as that ID has the highest priority during bus arbitration (even on a 16 bit bus). The SCSI ID of a device in a drive enclosure that has a backplane is set either by jumpers or by the slot in the enclosure the device is installed into, depending on the model of the enclosure. In the latter case, each slot on the enclosure's back plane delivers control signals to the drive to select a unique SCSI ID. A SCSI enclosure without a backplane often has a switch for each drive to choose the drive's SCSI ID. The enclosure is packaged with connectors that must be plugged into the drive where the jumpers are typically located; the switch emulates the necessary jumpers. While there is no standard Multimedia Systems- M.Sc(IT) 46 that makes this work, drive designers typically set up their jumper headers in a consistent format that matches the way that these switches implement. Note that a SCSI target device (which can be called a "physical unit") is often divided into smaller "logical units." For example, a high-end disk subsystem may be a single SCSI device but contain dozens of individual disk drives, each of which is a logical unit (more commonly, it is not that simple—virtual disk devices are generated by the subsystem based on the storage in those physical drives, and each virtual disk device is a logical unit). The SCSI ID, WWNN, etc. in this case identifies the whole subsystem, and a second number, the logical unit number (LUN) identifies a disk device within the subsystem. It is quite common, though incorrect, to refer to the logical unit itself as a "LUN." Accordingly, the actual LUN may be called a "LUN number" or "LUN id". Setting the bootable (or first) hard disk to SCSI ID 0 is an accepted IT community recommendation. SCSI ID 2 is usually set aside for the Floppy drive while SCSI ID 3 is typically for a CD ROM. 6.4.5 SCSI enclosure services In larger SCSI servers, the disk-drive devices are housed in an intelligent enclosure that supports SCSI Enclosure Services (SES). The initiator can communicate with the enclosure using a specialized set of SCSI commands to access power, cooling, and other non-data characteristics. Check Your Progress 1 List a few types of SCSI. Notes: a) Write your answers in the space given below. b) Check your answers with the one given at the end of this lesson. …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… 6.5 Media Control Interface (MCI) The Media Control Interface, MCI in short, is an aging API for controlling multimedia peripherals connected to a Microsoft Windows or OS/2 computer. MCI makes it very simple to write a program which can play a wide variety of media files and even to record sound by just passing commands as strings. It uses relations described in Windows registries or in the [MCI] section of the file SYSTEM.INI. Multimedia Systems- M.Sc(IT) 47 The MCI interface is a high-level API developed by Microsoft and IBM for controlling multimedia devices, such as CD-ROM players and audio controllers. The advantage is that MCI commands can be transmitted both from the programming language and from the scripting language (open script, lingo). For a number of years, the MCI interface has been phased out in favor of the DirectX APIs. 6.5.1 MCI Devices The Media Control Interface consists of 4 parts:  AVIVideo  CDAudio  Sequencer  WaveAudio Each of these so-called MCI devices can play a certain type of files e.g. AVI Video plays avi files, CDAudio plays cd tracks among others. Other MCI devices have also been made available over time. 6.5.2 Playing media through the MCI interface To play a type of media, it needs to be initialized correctly using MCI commands. These commands are subdivided into categories:  System Commands  Required Commands  Basic Commands  Extended Commands 6.6 IDE Usually storage devices connect to the computer through an Integrated Drive Electronics (IDE) interface. Essentially, an IDE interface is a standard way for a storage device to connect to a computer. IDE is actually not the true technical name for the interface standard. The original name, AT Attachment (ATA), signified that the interface was initially developed for the IBM AT computer. IDE was created as a way to standardize the use of hard drives in computers. The basic concept behind IDE is that the hard drive and the controller should be combined. The controller is a small circuit board with chips that provide guidance as to exactly how the hard drive stores and accesses data. Most controllers also include some memory that acts as a buffer to enhance hard drive performance. Before IDE, controllers and hard drives were separate and often proprietary. In other words, a controller from one manufacturer might not work with a hard drive from another Multimedia Systems- M.Sc(IT) 50 6.9 Lesson-end activities 1. Identify the SYSTEM.INI file present in a computer and find the list of devices installed in a computer. Try to identify the settings for each device. 6.10 Model answers to “Check your progress” 1. A few types of SCSI are Ultra SCSI, Wide SCSI, SCSI-1, SCSI-2 and SCSI-3 2. The connecting devices discussed in this lesson are SCSI, IDE, MCI and USB 6.11 References 1. The Essential Guide to Computer Data Storage: From Floppy to DVD By Andrei Khurshudov 2. The Scsi Bus and Ide Interface: Protocols, Applications and Programming By Friedhelm Schmidt 3. ”Multimedia Computing, Communication and application” By Steinmetz and Klara Nahrstedt. 4. “Multimedia Making it work” By Tay Vaughan. Multimedia Systems- M.Sc(IT) 51 Lesson 7 Multimedia Hardware – Storage Devices Contents 7.0 Aims and Objectives 7.1 Introduction 7.2 Memory and Storage Devices 7.3 Random Access Memory 7.4 Read Only Memory 7.5 Floppy and Hard Disks 7.6 Zip, jaz, SyQuest, and Optical storage devices 7.7 Digital Versatile Disk 7.8 CD ROM players 7.9 CD Recorders 7.10 Video Disc Players 7.11 Let us sum up 7.12 Model answers to “Check your progress” 7.13 References 7.0 Aims and Objectives The aim of this lesson is to educate the learners about the second category of multimedia hardware which is the storage device. At the end of this lesson the learner will have an in-depth knowledge on the storage devices and their specifications. 7.1 Introduction A data storage device is a device for recording (storing) information (data). Recording can be done using virtually any form of energy. A storage device may hold information, process information, or both. A device that only holds information is a recording medium. Devices that process information (data storage equipment) may both access a separate portable (removable) recording medium or a permanent component to store and retrieve information. Electronic data storage is storage which requires electrical power to store and retrieve that data. Most storage devices that do not require visual optics to read data fall into this category. Electronic data may be stored in either an analog or digital signal format. This type of data is considered to be electronically encoded data, whether or not it is electronically stored. Most electronic data storage media (including some forms of computer storage) are considered permanent (non-volatile) storage, that is, the data will remain stored when power is removed from the device. In contrast, electronically stored information is considered volatile memory. Multimedia Systems- M.Sc(IT) 52 7.2 MEMORY AND STORAGE DEVICES By adding more memory and storage space to the computer, the computing needs and habits to keep pace, filling the new capacity. To estimate the memory requirements of a multimedia project- the space required on a floppy disk, hard disk, or CD-ROM, not the random access sense of the project’s content and scope. Color images, Sound bites, video clips, and the programming code that glues it all together require memory; if there are many of these elements, you will need even more. If you are making multimedia, you will also need to allocate memory for storing and archiving working files used during production, original audio and video clips, edited pieces, and final mixed pieces, production paperwork and correspondence, and at least one backup of your project files, with a second backup stored at another location. 7.3 Random Access Memory (RAM) RAM is the main memory where the Operating system is initially loaded and the application programs are loaded at a later stage. RAM is volatile in nature and every program that is quit/exit is removed from the RAM. More the RAM capacity, higher will be the processing speed. If there is a budget constraint, then it is certain to produce a multimedia project on a slower or limited-memory computer. On the other hand, it is profoundly frustrating to face memory (RAM) shortages time after time, when you’re attempting to keep multiple applications and files open simultaneously. It is also frustrating to wait the extra seconds required oh each editing step when working with multimedia material on a slow processor. On the Macintosh, the minimum RAM configuration for serious multimedia production is about 32MB; but even64MB and 256MB systems are becoming common, because while digitizing audio or video, you can store much more data much more quickly in RAM. And when you’re using some software, you can quickly chew up available RAM – for example, Photoshop (16MB minimum, 20MB recommended); After Effects (32MBrequired), Director (8MB minimum, 20MB better); Page maker (24MB recommended); Illustrator (16MB recommended); Microsoft Office (12MB recommended). In spite of all the marketing hype about processor speed, this speed is ineffective if not accompanied by sufficient RAM. A fast processor without enough RAM may waste processor cycles while it swaps needed portions of program code into and out of memory. In some cases, increasing available RAM may show more performance improvement on your system than upgrading the processor clip. On an MPC platform, multimedia authoring can also consume a great deal of memory. It may be needed to open many large graphics and audio files, as well as your Multimedia Systems- M.Sc(IT) 55 Hollywood. DVD also supports Dolby pro-Logic Surround Sound, standard stereo and mono audio. Users can randomly access any section of the disc and use the slow-motion and freeze-frame features during movies. Audio tracks can be programmed for as many as 8 different languages, with graphic subtitles in 32 languages. Some manufactures such as Toshiba are already providing parental control features in their players (user’s select lockout ratings from G to NC-17). 7.8 CD-ROM Players Compact disc read-only memory (CD-ROM) players have become an integral part of the multimedia development workstation and are important delivery vehicle for large, mass-produced projects. A wide variety of developer utilities, graphic backgrounds, stock photography and sounds, applications, games, reference texts, and educational software are available only on this medium. CD-ROM players have typically been very slow to access and transmit data (150k per second, which is the speed required of consumer Red Book Audio CDs), but new developments have led to double, triple, quadruple, speed and even 24x drives designed specifically for computer (not Red Book Audio) use. These faster drives spool up like washing machines on the spin cycle and can be somewhat noisy, especially if the inserted compact disc is not evenly balanced. 7.9 CD Recorders With a compact disc recorder, you can make your own CDs using special CD- recordable (CD-R) blank optical discs to create a CD in most formats of CD-ROM and CD-Audio. The machines are made by Sony, Phillips, Ricoh, Kodak, JVC, Yamaha, and Pinnacle. Software, such as Adaptec’s Toast for Macintosh or Easy CD Creator for Windows, lets you organize files on your hard disk(s) into a “virtual” structure, then writes them to the CD in that order. CD-R discs are made differently than normal CDs but can play in any CD-Audio or CD-ROM player. They are available in either a “63 minute” or “74 minute” capacity for the former, that means about 560MB, and for the latter, about 650MB. These write-once CDs make excellent high-capacity file archives and are used extensively by multimedia developers for premastering and testing CD- ROM projects and titles. 7.10 Videodisc Players Videodisc players (commercial, not consumer quality) can be used in conjunction with the computer to deliver multimedia applications. You can control the videodisc player from your authoring software with X-Commands (XCMDs) on the Macintosh and with MCI commands in Windows. The output of the videodisc player is an analog television signal, so you must setup a television separate from your computer monitor or use a video digitizing board to “window” the analog signal on your monitor. Multimedia Systems- M.Sc(IT) 56 Check Your Progress 1 Specify any five storage devices and list their storage capacity. Notes: a) Write your answers in the space given below. b) Check your answers with the one given at the end of this lesson. …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… 7.11 Let us sum up In this lesson we have learnt about the storage devices used in multimedia system. The following points have been discussed :  RAM is a storage devices for temporary storage which is used to store all the application programs under execution.  The secondary storage devices are used to store the data permanently. The storage capacity of secondary storage is more compared with RAM. 7.12 Model answers to “Check your progress” 1. A few of the following devices could be listed as storage devices used for multimedia : Random Access Memory, Read Only Memory, Floppy and Hard Disks, Zip, jaz, SyQuest, and Optical storage devices, Digital Versatile Disk, CD ROM players, CD Recorders, Video Disc Players 7.13 References 1. “Multimedia Making it work” By Tay Vaughan 2. The Essential Guide to Computer Data Storage: From Floppy to DVD By Andrei Khurshudov 3. ”Multimedia Computing, Communication and application” By Steinmetz and Klara Nahrstedt. 4. “Multimedia and Imaging Databases” By Setrag Khoshafian, A. Brad Baker Multimedia Systems- M.Sc(IT) 57 Lesson 8 Multimedia Storage – Optical Devices Contents 8.0 Aims and Objectives 8.1 Introduction 8.2 CD-ROM 8.3 Logical formats of CD-ROM 8.4 DVD 8.4.1 DVD disc capacity 8.4.2 DVD recordable and rewritable 8.4.3 Security in DVD 8.4.4 Competitors and successors to DVD 8.5 Let us sum up 8.6 Lesson-end activities 8.7 Model answers to “Check your progress” 8.8 References 8.0 Aims and Objectives In this lesson we will learn the different optical storage devices and their specifications. At the end of this lesson the learner will; i) Understand optical storage devices. ii) Find the specifications of different optical storage devices. iii) Specify the capabilities of DVD 8.1 Introduction Optical storage devices have become the order of the day. The high storage capacity available in the optical storage devices has influenced it as storage for multimedia content. Apart from the high storage capacity the optical storage devices have higher data transfer rate. 8.2 CD-ROM A Compact Disc or CD is an optical disc used to store digital data, originally developed for storing digital audio. The CD, available on the market since late 1982, remains the standard playback medium for commercial audio recordings to the present day, though it has lost ground in recent years to MP3 players. An audio CD consists of one or more stereo tracks stored using 16-bit PCM coding at a sampling rate of 44.1 kHz. Standard CDs have a diameter of 120 mm and can hold approximately 80 minutes of audio. There are also 80 mm discs, sometimes used for Multimedia Systems- M.Sc(IT) 60 minutes less. A disc with data packed slightly more densely is tolerated by most players (though some old ones fail). Using a linear velocity of 1.2 m/s and a track pitch of 1.5 µm leads to a playing time of 80 minutes, or a capacity of 700 MB. Even higher capacities on non-standard discs (up to 99 minutes) are available at least as recordable, but generally the tighter the tracks are squeezed the worse the compatibility. Data structure The smallest entity in a CD is called a frame. A frame consists of 33 bytes and contains six complete 16-bit stereo samples (2 bytes × 2 channels × six samples equals 24 bytes). The other nine bytes consist of eight Cross-Interleaved Reed-Solomon Coding error correction bytes and one subcode byte, used for control and display. Each byte is translated into a 14-bit word using Eight-to- Fourteen Modulation, which alternates with 3-bit merging words. In total we have 33 × (14 + 3) = 561 bits. A 27-bit unique synchronization word is added, so that the number of bits in a frame totals 588 (of which only 192 bits are music). These 588-bit frames are in turn grouped into sectors. Each sector contains 98 frames, totaling 98 × 24 = 2352 bytes of music. The CD is played at a speed of 75 sectors per second, which results in 176,400 bytes per second. Divided by 2 channels and 2 bytes per sample, this result in a sample rate of 44,100 samples per second. "Frame" For the Red Book stereo audio CD, the time format is commonly measured in minutes, seconds and frames (mm:ss:ff), where one frame corresponds to one sector, or 1/75th of a second of stereo sound. Note that in this context, the term frame is erroneously applied in editing applications and does not denote the physical frame described above. In editing and extracting, the frame is the smallest addressable time interval for an audio CD, meaning that track start and end positions can only be defined in 1/75 second steps. Logical structure The largest entity on a CD is called a track. A CD can contain up to 99 tracks (including a data track for mixed mode discs). Each track can in turn have up to 100 indexes, though players which handle this feature are rarely found outside of pro audio, particularly radio broadcasting. The vast majority of songs are recorded under index 1, with the pre-gap being index 0. Sometimes hidden tracks are placed at the end of the last track of the disc, often using index 2 or 3. This is also the case with some discs offering "101 sound effects", with 100 and 101 being index 2 and 3 on track 99. The index, if used, is occasionally put on the track listing as a decimal part of the track number, such as 99.2 or 99.3. Multimedia Systems- M.Sc(IT) 61 CD-Text CD-Text is an extension of the Red Book specification for audio CD that allows for storage of additional text information (e.g., album name, song name, artist) on a standards-compliant audio CD. The information is stored either in the lead-in area of the CD, where there is roughly five kilobytes of space available, or in the subcode channels R to W on the disc, which can store about 31 megabytes. http://en.wikipedia.org/wiki/Image:CDTXlogo.svg CD + Graphics Compact Disc + Graphics (CD+G) is a special audio compact disc that contains graphics data in addition to the audio data on the disc. The disc can be played on a regular audio CD player, but when played on a special CD+G player, can output a graphics signal (typically, the CD+G player is hooked up to a television set or a computer monitor); these graphics are almost exclusively used to display lyrics on a television set for karaoke performers to sing along with. CD + Extended Graphics Compact Disc + Extended Graphics (CD+EG, also known as CD+XG) is an improved variant of the Compact Disc + Graphics (CD+G) format. Like CD+G, CD+EG utilizes basic CD-ROM features to display text and video information in addition to the music being played. This extra data is stored in subcode channels R-W. CD-MIDI Compact Disc MIDI or CD-MIDI is a type of audio CD where sound is recorded in MIDI format, rather than the PCM format of Red Book audio CD. This provides much greater capacity in terms of playback duration, but MIDI playback is typically less realistic than PCM playback. Video CD Video CD (aka VCD, View CD, Compact Disc digital video) is a standard digital format for storing video on a Compact Disc. VCDs are playable in dedicated VCD players, most modern DVD-Video players, and some video game consoles. The VCD standard was created in 1993 by Sony, Philips, Matsushita, and JVC and is referred to as the White Book standard. Overall picture quality is intended to be comparable to VHS video, though VHS has twice as many scanlines (approximately 480 NTSC and 580 PAL) and therefore double the vertical resolution. Poorly compressed video in VCD tends to be of lower quality than VHS video, but VCD exhibits block artifacts rather than analog noise. Multimedia Systems- M.Sc(IT) 62 Super Video CD Super Video CD (Super Video Compact Disc or SVCD) is a format used for storing video on standard compact discs. SVCD was intended as a successor to Video CD and an alternative to DVD-Video, and falls somewhere between both in terms of technical capability and picture quality. SVCD has two-thirds the resolution of DVD, and over 2.7 times the resolution of VCD. One CD-R disc can hold up to 60 minutes of standard quality SVCD-format video. While no specific limit on SVCD video length is mandated by the specification, one must lower the video bitrate, and therefore quality, in order to accommodate very long videos. It is usually difficult to fit much more than 100 minutes of video onto one SVCD without incurring significant quality loss, and many hardware players are unable to play video with an instantaneous bitrate lower than 300 to 600 kilobits per second. Photo CD Photo CD is a system designed by Kodak for digitizing and storing photos in a CD. Launched in 1992, the discs were designed to hold nearly 100 high quality images, scanned prints and slides using special proprietary encoding. Photo CD discs are defined in the Beige Book and conform to the CD-ROM XA and CD-i Bridge specifications as well. They are intended to play on CD-i players, Photo CD players and any computer with the suitable software irrespective of the operating system. The images can also be printed out on photographic paper with a special Kodak machine. Picture CD Picture CD is another photo product by Kodak, following on from the earlier Photo CD product. It holds photos from a single roll of color film, stored at 1024×1536 resolution using JPEG compression. The product is aimed at consumers. CD Interactive The Philips "Green Book" specifies the standard for interactive multimedia Compact Discs designed for CD-i players. This Compact Disc format is unusual because it hides the initial tracks which contains the software and data files used by CD-i players by omitting the tracks from the disc's Table of Contents. This causes audio CD players to skip the CD-i data tracks. This is different from the CD-i Ready format, which puts CD-i software and data into the pregap of Track 1. Multimedia Systems- M.Sc(IT) 65 8.4.1 DVD disc capacity Single layer capacity Dual/Double layer capacity Physical size GB GiB GB GiB 12 cm, single sided 4.7 4.37 8.54 7.95 12 cm, double sided 9.4 8.74 17.08 15.90 8 cm, single sided 1.4 1.30 2.6 2.42 8 cm, double sided 2.8 2.61 5.2 4.84 The 12 cm type is a standard DVD, and the 8 cm variety is known as a mini-DVD. These are the same sizes as a standard CD and a mini-CD. Note: GB here means gigabyte, equal to 109 (or 1,000,000,000) bytes. Many programs will display gibibyte (GiB), equal to 230 (or 1,073,741,824) bytes. Example: A disc with 8.5 GB capacity is equivalent to: (8.5 × 1,000,000,000) / 1,073,741,824 ≈ 7.92 GiB. Capacity Note: There is a difference in capacity (storage space) between + and - DL DVD formats. For example, the 12 cm single sided disc has capacities: Disc Type Sectors bytes GB GiB DVD-R SL 2,298,496 4,707,319,808 4.7 4.384 DVD+R SL 2,295,104 4,700,372,992 4.7 4.378 DVD-R DL 4,171,712 8,543,666,176 8.5 7.957 DVD+R DL 4,173,824 8,547,991,552 8.5 7.961 Multimedia Systems- M.Sc(IT) 66 Technology DVD uses 650 nm wavelength laser diode light as opposed to 780 nm for CD. This permits a smaller spot on the media surface that is 1.32 µm for DVD while it was 2.11 µm for CD. Writing speeds for DVD were 1x, that is 1350 kB/s (1318 KiB/s), in first drives and media models. More recent models at 18x or 20x have 18 or 20 times that speed. Note that for CD drives, 1x means 153.6 kB/s (150 KiB/s), 9 times slower. DVD FAQ 8.4.2 DVD recordable and rewritable HP initially developed recordable DVD media from the need to store data for back-up and transport. DVD recordables are now also used for consumer audio and video recording. Three formats were developed: DVD-R/RW (minus/dash), DVD+R/RW (plus), DVD-RAM. Dual layer recording Dual Layer recording allows DVD-R and DVD+R discs to store significantly more data, up to 8.5 Gigabytes per side, per disc, compared with 4.7 Gigabytes for single- layer discs. DVD-R DL was developed for the DVD Forum by Pioneer Corporation, DVD+R DL was developed for the DVD+RW Alliance by Philips and Mitsubishi Kagaku Media (MKM). A Dual Layer disc differs from its usual DVD counterpart by employing a second physical layer within the disc itself. The drive with Dual Layer capability accesses the second layer by shining the laser through the first semi-transparent layer. The layer change mechanism in some DVD players can show a noticeable pause, as long as two seconds by some accounts. This caused more than a few viewers to worry that their dual layer discs were damaged or defective, with the end result that studios began listing a standard message explaining the dual layer pausing effect on all dual layer disc packaging. DVD recordable discs supporting this technology are backward compatible with some existing DVD players and DVD-ROM drives. Many current DVD recorders support dual-layer technology, and the price is now comparable to that of single-layer drives, though the blank media remain more expensive. DVD-Video DVD-Video is a standard for storing video content on DVD media. Though many resolutions and formats are supported, most consumer DVD-Video discs use either 4:3 or anamorphic 16:9 aspect ratio MPEG-2 video, stored at a resolution Multimedia Systems- M.Sc(IT) 67 of 720×480 (NTSC) or 720×576 (PAL) at 24, 30, or 60 FPS. Audio is commonly stored using the Dolby Digital (AC-3) or Digital Theater System (DTS) formats, ranging from 16-bits/48kHz to 24-bits/96kHz format with monaural to 7.1 channel "Surround Sound" presentation, and/or MPEG-1 Layer 2. Although the specifications for video and audio requirements vary by global region and television system, many DVD players support all possible formats. DVD-Video also supports features like menus, selectable subtitles, multiple camera angles, and multiple audio tracks. DVD-Audio DVD-Audio is a format for delivering high-fidelity audio content on a DVD. It offers many channel configuration options (from mono to 7.1 surround sound) at various sampling frequencies (up to 24-bits/192kHz versus CDDA's 16-bits/44.1kHz). Compared with the CD format, the much higher capacity DVD format enables the inclusion of considerably more music (with respect to total running time and quantity of songs) and/or far higher audio quality (reflected by higher linear sampling rates and higher vertical bit- rates, and/or additional channels for spatial sound reproduction). Despite DVD-Audio's superior technical specifications, there is debate as to whether the resulting audio enhancements are distinguishable in typical listening environments. DVD-Audio currently forms a niche market, probably due to the very sort of format war with rival standard SACD that DVD-Video avoided. Check Your Progress 1 Specify the different storage capacities available in a DVD Notes: a) Write your answers in the space given below. b) Check your answers with the one given at the end of this lesson. …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… 8.4.3 Security in DVD DVD-Audio discs employ a robust copy prevention mechanism, called Content Protection for Prerecorded Media (CPPM) developed by the 4C group (IBM, Intel, Matsushita, and Toshiba). To date, CPPM has not been "broken" in the sense that DVD-Video's CSS has been broken, but ways to circumvent it have been developed. By modifying commercial DVD(-Audio) playback software to write the decrypted and decoded audio streams to the hard disk, users can, essentially, extract content from DVD-Audio discs much in the same way they can from DVD-Video discs. Multimedia Systems- M.Sc(IT) 70 Lesson 9 Multimedia Hardware – Input Devices, Output Devices, Communication Devices Contents 9.0 Aims and Objectives 9.1 Introduction 9.2 Input Devices 9.3 Output Hardwares 9.4 Communication Devices 9.5 Let us sum up 9.6 Lesson-end activities 9.7 Model answers to “Check your progress” 9.8 References 9.0 Aims and Objectives This lesson aims at introducing the multimedia hardware used for providing interactivity between the user and the multimedia software. At the end of this lesson the learner will be able to i. Identify input devices ii. Identify and select output hardware iii. List and understand different communication devices 9.1 Introduction An input device is a hardware mechanism that transforms information in the external world for consumption by a computer. An output device is a hardware used to communicate the result of data processing carried out by the user or CPU. 9.2 Input devices Often, input devices are under direct control by a human user, who uses them to communicate commands or other information to be processed by the computer, which may then transmit feedback to the user through an output device. Input and output devices together make up the hardware interface between a computer and the user or external world. Typical examples of input devices include keyboards and mice. However, there are others which provide many more degrees of freedom. In general, any sensor which monitors, scans for and accepts information from the external world can be considered an input device, whether or not the information is under the direct control of a user. Multimedia Systems- M.Sc(IT) 71 9.2.1 Classification of Input Devices Input devices can be classified according to:-  the modality of input (e.g. mechanical motion, audio, visual, sound, etc.)  whether the input is discrete (e.g. keypresses) or continuous (e.g. a mouse's position, though digitized into a discrete quantity, is high-resolution enough to be thought of as continuous)  the number of degrees of freedom involved (e.g. many mice allow 2D positional input, but some devices allow 3D input, such as the Logitech Magellan Space Mouse) Pointing devices, which are input devices used to specify a position in space, can further be classified according to  Whether the input is direct or indirect. With direct input, the input space coincides with the display space, i.e. pointing is done in the space where visual feedback or the cursor appears. Touchscreens and light pens involve direct input. Examples involving indirect input include the mouse and trackball.  Whether the positional information is absolute (e.g. on a touch screen) or relative (e.g. with a mouse that can be lifted and repositioned) Note that direct input is almost necessarily absolute, but indirect input may be either absolute or relative. For example, digitizing graphics tablets that do not have an embedded screen involve indirect input, and sense absolute positions and are often run in an absolute input mode, but they may also be setup to simulate a relative input mode where the stylus or puck can be lifted and repositioned. 9.2.2 Keyboards A keyboard is the most common method of interaction with a computer. Keyboards provide various tactile responses (from firm to mushy) and have various layouts depending upon your computer system and keyboard model. Keyboards are typically rated for at least 50 million cycles (the number of times a key can be pressed before it might suffer breakdown). The most common keyboard for PCs is the 101 style (which provides 101 keys), although many styles are available with more are fewer special keys, LEDs, and others features, such as a plastic membrane cover for industrial or food-service applications or flexible “ergonomic” styles. Macintosh keyboards connect to the Apple Desktop Bus (ADB), which manages all forms of user input- from digitizing tablets to mice. Examples of types of keyboards include  Computer keyboard  Keyer Multimedia Systems- M.Sc(IT) 72  Chorded keyboard  LPFK 9.2.3 Pointing devices A pointing device is any computer hardware component (specifically human interface device) that allows a user to input spatial (ie, continuous and multi-dimensional) data to a computer. CAD systems and graphical user interfaces (GUI) allow the user to control and provide data to the computer using physical gestures - point, click, and drag - typically by moving a hand-held mouse across the surface of the physical desktop and activating switches on the mouse. While the most common pointing device by far is the mouse, many more devices have been developed. However, mouse is commonly used as a metaphor for devices that move the cursor. A mouse is the standard tool for interacting with a graphical user interface (GUI). All Macintosh computers require a mouse; on PCs, mice are not required but recommended. Even though the Windows environment accepts keyboard entry in lieu of mouse point-and-click actions, your multimedia project should typically be designed with the mouse or touchscreen in mind. The buttons the mouse provide additional user input, such as pointing and double-clicking to open a document, or the click-and-drag operation, in which the mouse button is pressed and held down to drag (move) an object, or to move to and select an item on a pull-down menu, or to access context-sensitive help. The Apple mouse has one button; PC mice may have as many as three. Examples of common pointing devices include  mouse  trackball  touchpad  spaceBall - 6 degrees-of-freedom controller  touchscreen  graphics tablets (or digitizing tablet) that use a stylus  light pen  light gun  eye tracking devices  steering wheel - can be thought of as a 1D pointing device  yoke (aircraft)  jog dial - another 1D pointing device  isotonic joysticks - where the user can freely change the position of the stick, with more or less constant force o joystick o analog stick  isometric joysticks - where the user controls the stick by varying the amount of force they push with, and the position of the stick remains more or less constant o pointing stick Multimedia Systems- M.Sc(IT) 75 Touchscreen recommended for day-to-day computer work, but are excellent for multimedia applications in a kiosk, at a trade show, or in a museum delivery system- anything involving public input and simple tasks. When your project is designed to use a touchscreen, the monitor is the only input device required, so you can secure all other system hardware behind locked doors to prevent theft or tampering. Check Your Progress 1 List a few input devices. Notes: a) Write your answers in the space given below. b) Check your answers with the one given at the end of this lesson. …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… 9.3 OUTPUT DEVICES Presentation of the audio and visual components of the multimedia project requires hardware that may or may not be included with the computer itself-speakers, amplifiers, monitors, motion video devices, and capable storage systems. The better the equipment, of course, the better the presentation. There is no greater test of the benefits of good output hardware than to feed the audio output of your computer into an external amplifier system: suddenly the bass sounds become deeper and richer, and even music sampled at low quality may seem to be acceptable. 9.3.1.Audio devices All Macintoshes are equipped with an internal speaker and a dedicated sound clip, and they are capable of audio output without additional hardware and/or software. To take advantage of built-in stereo sound, external speaker are required. Digitizing sound on the Macintosh requires an external microphone and sound editing/recording software such as SoundEdit16 from Macromedia, Alchemy from Passport, or SoundDesingner from DigiDesign. 9.3.2 Amplifiers and Speakers Often the speakers used during a project’s development will not be adequate for its presentation. Speakers with built-in amplifiers or attached to an external amplifier are important when the project will be presented to a large audience or in a noisy setting. 9.3.3 Monitors The monitor needed for development of multimedia projects depends on the type of multimedia application created, as well as what computer is being used. A wide variety of monitors is available for both Macintoshes and PCs. High-end, large-screen graphics monitors are available for both, and they are expensive. Multimedia Systems- M.Sc(IT) 76 Serious multimedia developers will often attach more than one monitor to their computers, using add-on graphic board. This is because many authoring systems allow to work with several open windows at a time, so we can dedicate one monitor to viewing the work we are creating or designing, and we can perform various editing tasks in windows on other monitors that do not block the view of your work. Editing windows that overlap a work view when developing with Macromedia’s authoring environment, director, on one monitor. Developing in director is best with at least two monitors, one to view the work the other two view the “score”. A third monitor is often added by director developers to display the “Cast”. 9.3.4 Video Device No other contemporary message medium has the visual impact of video. With a video digitizing board installed in a computer, we can display a television picture on your monitor. Some boards include a frame-grabber feature for capturing the image and turning it in to a color bitmap, which can be saved as a PICT or TIFF file and then used as part of a graphic or a background in your project. Display of video on any computer platform requires manipulation of an enormous amount of data. When used in conjunction with videodisc players, which give precise control over the images being viewed, video cards you place an image in to a window on the computer monitor; a second television screen dedicated to video is not required. And video cards typically come with excellent special effects software. There are many video cards available today. Most of these support various video- in-a-window sizes, identification of source video, setup of play sequences are segments, special effects, frame grabbing, digital movie making; and some have built-in television tuners so you can watch your favorite programs in a window while working on other things. In windows, video overlay boards are controlled through the Media Control Interface. On the Macintosh, they are often controlled by external commands and functions (XCMDs and XFCNs) linked to your authoring software. Good video greatly enhances your project; poor video will ruin it. Whether you delivered your video from tape using VISCA controls, from videodisc, or as a QuickTime or AVI movie, it is important that your source material be of high quality. 9.3.5 Projectors When it is necessary to show a material to more viewers than can huddle around a computer monitor, it will be necessary to project it on to large screen or even a white- painted wall. Cathode-ray tube (CRT) projectors, liquid crystal display (LCD) panels attached to an overhead projector, stand-alone LCD projectors, and light-valve projectors are available to splash the work on to big-screen surfaces. CRT projectors have been around for quite a while- they are the original “big- screen” televisions. They use three separate projection tubes and lenses (red, green, and blue), and three color channels of light must “converge” accurately on the screen. Setup, focusing, and aligning are important to getting a clear and crisp picture. CRT projectors are compatible with the output of most computers as well as televisions. LCD panels are portable devices that fit in a briefcase. The panel is placed on the glass surface of a standard overhead projector available in most schools, conference Multimedia Systems- M.Sc(IT) 77 rooms, and meeting halls. While they overhead projectors does the projection work, the panel is connected to the computer and provides the image, in thousands of colors and, with active-matrix technology, at speeds that allow full-motion video and animation. Because LCD panels are small, they are popular for on-the-road presentations, often connected to a laptop computer and using a locally available overhead projector. More complete LCD projection panels contain a projection lamp and lenses and do not recover a separate overheads projector. They typically produce an image brighter and shaper than the simple panel model, but they are some what large and cannot travel in a briefcase. Light-valves complete with high-end CRT projectors and use a liquid crystal technology in which a low-intensity color image modulates a high-intensity light beam. These units are expensive, but the image from a light-valve projector is very bright and color saturated can be projected onto screen as wide as 10 meters. 9.3.6 Printers With the advent of reasonably priced color printers, hard-copy output has entered the multimedia scene. From storyboards to presentation to production of collateral marketing material, color printers have become an important part of the multimedia development environment. Color helps clarify concepts, improve understanding and retention of information, and organize complex data. As multimedia designers already know intelligent use of colors is critical to the success of a project. Tektronix offers both solid ink and laser options, and either Phases 560 will print more than 10000 pages at a rate of 5 color pages or 14 monochrome pages per minute before requiring new toner. Epson provides lower-cost and lower-performance solutions for home and small business users; Hewlett Packard’s Color LaserJet line competes with both. Most printer manufactures offer a color model-just as all computers once used monochrome monitors but are now color, all printers will became color printers. Check Your Progress 2 List a few output devices. Notes: a) Write your answers in the space given below. b) Check your answers with the one given at the end of this lesson. …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… Multimedia Systems- M.Sc(IT) 80 9.5 Let us sum up In this lesson we have learnt the details about input devices, connecting devices and output devices. We have discussed the following key points in this lesson :  Input Devices and Output devices provide interactivity.  Communication devices enables data transfer. 9.6 Lesson-end activities 1. Most input and output devices have a certain resolution. Locate the specifications on the web for a CRT monitor, a LCD monitor, a scanner, and a digital camera. Note the manufacturer, model, and resolution for each one. Document your findings. 2. List the input devices present in a computer by identifying it from the control panel. 9.7 Model answers to “Check your progress” 1. A few of the following input devices can be listed : Keyboard, Mouse, Microphone, Scanner, Touchscreen, Joystick, Lightpen, tablets. 2. The following is the list of Output devices. A few of them can be listed. Printer, Speaker, Plotter, Monitor, Projectors 9.8 References 1. Multimedia Making it work” By Tay Vaughan 2. “Multimedia in Practice – Technology and applications” By Jeffcoat 3. http://www.wacona.com/input/input.html 4. www.webopedia.com/TERM/I/input_device.html 5. http://en.wikipedia.org/wiki/Input_device Multimedia Systems- M.Sc(IT) 81 Lesson 10 Multimedia Workstation Contents 10.0 Aims and Objectives 10.1 Introduction 10.2 Communication Architecture 10.3 Hybrid Systems 10.4 Digital System 10.5 Multimedia Workstation 10.6 Preference of Operating System for workstation 10.7 Let us sum up 10.8 Lesson-end activities 10.9 Model answers to “Check your progress” 10.10 References 10.0 Aims and Objectives In this lesson we will learn the different requirements for a computer to become a multimedia workstation. At the end of this chapter the learner will be able to identify the requirements for making a computer, a multimedia workstation. 10.1 Introduction A multimedia workstation is computer with facilities to handle multimedia objects such as text, audio, video, animation and images. A multimedia workstation was earlier identified as MPC (Multimedia Personal Computer). In the current scenario all computers are prebuilt with multimedia processing facilities. Hence it is not necessary to identify a computer as MPC. A multimedia system is comprised of both hardware and software components, but the major driving force behind a multimedia development is research and development in hardware capabilities. Besides the multimedia hardware capabilities of current personal computers (PCs) and workstations, computer networks with their increasing throughput and speed start to offer services which support multimedia communication systems. Also in this area, computer networking technology advances faster than the software. 10.2 Communication Architecture Local multimedia systems (i.e., multimedia workstations) frequently include a network interface (e.g., Ethernet card) through which they can communicate with each Multimedia Systems- M.Sc(IT) 82 other. However, the transmission of audio and video cannot be carried out with only the conventional communication infrastructure and network adapters. Until now, the solution was that continuous and discrete media have been considered in different environments, independently of each other. It means that fully different systems were built. For example, on the one hand, the analog telephone system provides audio transmission services using its original dial devices connected by copper wires to the telephone company’s nearest end office. The end offices are connected to switching centers, called toll offices, and these centers are connected through high bandwidth intertoll trunks to intermediate switching offices. This hierarchical structure allows for reliable audio communication. On the other hand, digital computer networks provide data transmission services at lower data rates using network adapters connected by copper wires to switches and routers. Even today, professional radio and television studios transmit audio and video streams in the form of analog signals, although most network components (e.g., switches), over which these signals are transmitted, work internally in a digital mode. 10.3 Hybrid Systems By using existing technologies, integration and interaction between analog and digital environments can be implemented. This integration approach is called the hybrid approach. The main advantage of this approach is the high quality of audio and video and all the necessary devices for input, output, storage and transfer that are available. The hybrid approach is used for studying application user interfaces, application programming interfaces or application scenarios. Integrated Device Control One possible integration approach is to provide a control of analog input/output audio-video components in the digital environment. Moreover, the connection between the sources (e.g., CD player, camera, microphone) and destinations (e.g., video recorder, write-able CD), or the switching of audio-video signals can be controlled digitally. Integrated Transmission Control A second possibility to integrate digital and analog components is to provide a common transmission control. This approach implies that analog audio-video sources and destinations are connected to the computer for control purposes to transmit continuous data over digital networks, such as a cable network. Multimedia Systems- M.Sc(IT) 85 On the one hand, to achieve a high storage density, for example, a Constant Linear Velocity (CLV) technique was defined for the CD-DA (Compact Disc Digital Audio). CLV guarantees that the data density is kept constant for the entire optical disk at the expense of a higher mean access time. On the other hand, to achieve time guarantees, i.e., lower mean access time, a Constant Angle Velocity (CAV) technique could be used. Because the time requirement is more important, the systems with a CAV are more suitable for multimedia than the systems with a CLV. Processor In a multimedia workstation, the necessary work is distributed among different processors. Although currently, and for the near future, this does not mean that all multimedia workstations must be multi-processor systems. The processors are designed for different tasks. For example, a Dedicated Signal Processor (DSP) allows compression and decompression of audio in real-time. Moreover, there can be special-purpose processors employed for video. The following Figure shows an example of a multi- processor for multimedia workstations envisioned for the future. Operating System Another possible variant to provide computation of discrete and continuous data in a multimedia workstation could be distinguishing between processes for discrete data computation and for continuous data processing. These processes could run on separate processors. Given an adequate operating system, perhaps even one processor could be shared according to the requirements between processes for discrete and continuous data. Vector 1 Vector 2 Vector 3 CPU 1 CPU 2 CPU 3 CPU 4 B us In te rfa ce D V I Te ch no lo gy Cache Example of a Multiprocessor System Multimedia Systems- M.Sc(IT) 86 Check Your Progress 1 List a few components required for a multimedia workstation. Notes: a) Write your answers in the space given below. b) Check your answers with the one given at the end of this lesson. …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… 10.6 Preference of Operating System for Workstation. Selection of the proper platform for developing the multimedia project may be based on your personal preference of computer, your budget constraints, and project delivery requirements, and the type of material and content in the project. Many developers believe that multimedia project development is smoother and easier on the Macintosh than in Windows, even though projects destined to run in Windows must then be ported across platforms. But hardware and authoring software tools for Windows have improved; today you can produce many multimedia projects with equal ease in either the Windows or Macintosh environment. 10.6.1 The Macintosh Platform All Macintoshes can record and play sound. Many include hardware and software for digitizing and editing video and producing DVD discs. High-quality graphics capability is available “out of the box.” Unlike the Windows environment, where users can operate any application with keyboard input, the Macintosh requires a mouse. The Macintosh computer you will need for developing a project depends entirely upon the project’s delivery requirements, its content, and the tools you will need for production. 10.6.2 The Windows Platform Unlike the Apple Macintosh computer, a Windows computer is not a computer per se, but rather a collection of parts that are tied together by the requirements of the Windows operating system. Power supplies, processors, hard disks, CD-ROM players, video and audio components, monitors, key-boards and mice-it doesn’t matter where they come from or who makes them. Made in Texas, Taiwan, Indonesia, Ireland, Mexico, or Malaysia by widely known or little-known manufactures, these components are assembled and branded by Dell, IBM, Gateway, and other into computers that run Windows. In the early days, Microsoft organized the major PC hardware manufactures into the Multimedia PC Marketing Council to develop a set of specifications that would allow Windows to deliver a dependable multimedia experience. Multimedia Systems- M.Sc(IT) 87 10.6.3 Networking Macintosh and Windows Computers When a user works in a multimedia development environment consisting of a mixture of Macintosh and Windows computers, you will want them to communicate with each other. It may also be necessary to share other resources among them, such as printers. Local area networks (LANs) and wide area networks (WANs) can connect the members of a workgroup. In a LAN, workstations are usually located within a short distance of one another, on the same floor of a building, for example. WANs are communication systems spanning great distances, typically set up and managed by large corporation and institutions for their own use, or to share with other users. LANs allow direct communication and sharing of peripheral resources such as file servers, printers, scanners, and network modems. They use a variety of proprietary technologies, most commonly Ethernet or TokenRing, to perform the connections. They can usually be set up with twisted-pair telephone wire, but be sure to use “data-grade level 5” or “cat-5” wire-it makes a real difference, even if it’s a little more expensive! Bad wiring will give the user never-ending headache of intermittent and often untraceable crashes and failures. 10.7 Let us sum up In this lesson we have learnt the different requirement for a multimedia workstation.  A multimedia workstation is computer with facilities to handle multimedia objects such as text, audio, video, animation and images.  Macintosh is the pioneer in Multimedia OS. 10.8 Lesson-end activities 1. Identify the workstation components installed in a computer and list the multimedia component/object associated with each devices. 10.9 Model answers to “Check your progress” The multimedia workstation may consist of the following Bus, connecting devices, processor, Operating system, Primary Storage and Secondary storage. 10.10 References 1. "Multimedia:Concepts and Practice" By Stephen McGloughlin 2. ”Multimedia Computing, Communication and application” By Steinmetz and Klara Nahrstedt. 3. Digital Multimedia by Nigel Chapman, Jenny Chapman 4. Video and Image Processing in Multimedia Systems By Stephen W. Smoliar, HongJiang Zhang Multimedia Systems- M.Sc(IT) 90 user interfaces, which overcomes some of the limitations of written text. Rather than remaining static like traditional text, hypertext makes possible a dynamic organization of information through links and connections (called hyperlinks). Hypertext can be designed to perform various tasks; for instance when a user "clicks" on it or "hovers" over it, a bubble with a word definition may appear, or a web page on a related subject may load, or a video clip may run, or an application may open. The prefix hyper ("over" or "beyond") signifies the overcoming of the old linear constraints of written text. Types and uses of hypertext Hypertext documents can either be static (prepared and stored in advance) or dynamic (continually changing in response to user input). Static hypertext can be used to cross-reference collections of data in documents, software applications, or books on CD. A well-constructed system can also incorporate other user-interface conventions, such as menus and command lines. Hypertext can develop very complex and dynamic systems of linking and cross-referencing. The most famous implementation of hypertext is the World Wide Web. 11.4 Hypermedia Hypermedia is used as a logical extension of the term hypertext, in which graphics, audio, video, plain text and hyperlinks intertwine to create a generally non- linear medium of information. This contrasts with the broader term multimedia, which may be used to describe non-interactive linear presentations as well as hypermedia. Hypermedia should not be confused with hypergraphics or super-writing which is not a related subject. The World Wide Web is a classic example of hypermedia, whereas a non- interactive cinema presentation is an example of standard multimedia due to the absence of hyperlinks. Most modern hypermedia is delivered via electronic pages from a variety of systems. Audio hypermedia is emerging with voice command devices and voice browsing. 11.5 Hypertext and Hypermedia Communication reproduces knowledge stored in the human brain via several media. Documents are one method of transmitting information. Reading a document is an act of reconstructing knowledge. In an ideal case, knowledge transmission starts with an author and ends with a reconstruction of the same ideas by a reader. Today’s ordinary documents (excluding hypermedia), with their linear form, support neither the reconstruction of knowledge, nor simplify its reproduction. Knowledge must be artificially serialized before the actual exchange. Hence, it is transformed into a linear document and the structural information is integrated into the Multimedia Systems- M.Sc(IT) 91 actual content. In the case of hypertext and hypermedia, a graphical structure is possible in a document which may simplify the writing and reading processes. Check Your Progress 1 Distinguish hypertext and hypermedia. Notes: a) Write your answers in the space given below. b) Check your answers with the one given at the end of this lesson. …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… MIFF, SGML Document Edit Script/X, HyTime Script Compose Presentation Start ??? Layout Print Postscript format format Document Systems Interactive Hyper-/ Multimedia Systems Processable Form Final Form Problem Description Multimedia Systems- M.Sc(IT) 92 11.6 Hypertext, Hypermedia and multimedia A book or an article on a paper has a given structure and is represented in a sequential form. Although it is possible to read individual paragraphs without reading previous paragraphs, authors mostly assume a sequential reading. Therefore many paragraphs refer to previous learning in the document. Novels, as well as movies, for example, always assume a pure sequential reception. Scientific literature can consist of independent chapters, although mostly a sequential reading is assumed. Technical documentation (e.g., manuals) consist often of a collection of relatively independent information units. A lexicon or reference book about the Airbus, for example, is generated by several authors and always only parts are read sequentially. There also exist many cross references in such documentations which lead to multiple searches at different places for the reader. Here, an electronic help facility, consisting of information links, can be very significant. The following figure shows an example of such a link. The arrows point to such a relation between the information units (Logical Data Units - LDU’s). In a text (top left in the figure), a reference to the landing properties of aircrafts is given. These properties are demonstrated through a video sequence (bottom left in the figure). At another place in the text, sales of landing rights for the whole USA are shown (this is visualized in the form of a map, using graphics- bottom right in the figure). Further information about the airlines with their landing rights can be made visible graphically through a selection of a particular city. A special information about the number of the different airplanes sold with landing rights in Washington is shown at the top right in the figure with a bar diagram. Internally, the diagram information is presented in table form. The left bar points to the plane, which can be demonstrated with a video clip. Hypertext Data. An example of linking information of different media Multimedia Systems- M.Sc(IT) 95 Lesson 12 Document Architecture and MPEG Contents 12.0 Aims and Objectives 12.1 Introduction 12.2 Document Architecture - SGML 12.3 Open Document Architecture 12.3.1 Details of ODA 12.3.2 Layout Structure and logical structure 12.3.3 ODA and Multimedia 12.4 MHEG 12.4.1 Example of Interactive Multimedia 12.4.2 Derivation of Class Hierarchy 12.5 Let us sum up 12.6 Lesson-end activities 12.7 Model answers to “Check your progress” 12.8 References 12.0 Aims and Objectives This lesson aims at teaching the different document architecture followed in Multimedia. At the end of this lesson the learner will be able to : i) learn different document architectures. ii) enumerate the architecture of MHEG. 12.1 Introduction Exchanging documents entails exchanging the document content as well as the document structure. This requires that both documents have the same document architecture. The current standards in the document architecture are 1. Standard Generalized Markup Language 2. Open Document Architecture 12.2 Document Architecture - SGML The Standard Generalized Markup Language (SGML) was supported mostly by American publisher. Authors prepare the text, i.e., the content. They specify in a uniform way the title, tables, etc., without a description of the actual representation (e., script type and line distance). The publisher specifies the resulting layout. The basic idea is that the author uses tags for marking certain text parts. SGML determines the form of tags. But it does not specify their location or meaning. User Multimedia Systems- M.Sc(IT) 96 groups agree on the meaning of the tags. SGML makes a frame available with which the user specifies the syntax description in an object-specific system. Here, classes and objects, hierarchies of classes and objects, inheritance and the link to methods (processing instructions) can be used by the specification. SGML specifies the syntax, but not the semantics. For example, <title>Multimedia-Systems</title> <author>Felix Gatou</author> <side>IBM</side> <summary>This exceptional paper from Peter… This example shows an application of SGML in a text document. The following figure shows the processing of an SGML document. It is divided into two processes: Only the formatter knows the meaning of the tag and it transforms the document into a formatted document. The parser uses the tags, occurring in the document, in combination with the corresponding document type. Specification of the document SGML : Document processing – from the information to the presentation Multimedia Systems- M.Sc(IT) 97 structure is done with tags. Here, parts of the layout are linked together. This is based on the joint context between the originator of the document and the formatter process. It is one defined through SGML. 12.2.1 SGML and Multimedia Multimedia data are supported in the SGML standard only in the form of graphics. A graphical image as a CGM (Computer Graphics Metafile) is embedded in an SGML document. The standard does not refer to other media : <!ATTLIST video id ID #IMPLIED> <!ATTLIST video synch synch #MPLIED> <!ELEMENT video (audio, movpic)> <!ELEMENT audio (#NDATA)> -- not-text media <!ELEMENT movpic (#NDATA)> -- not-text media ….. <!ELEMENT story (preamble, body, postamble)> : A link to concrete data can be specified through #NDATA. The data are stored mostly externally in a separate file. The above example shows the definition of video which consists of audio and motion pictures. Multimedia information units must be presented properly. The synchronization between the components is very important here. 12.3 Open Document Architecture ODA The Open Document Architecture (ODA) was initially called the Office Document Architecture because it supports mostly office-oriented applications. The main goal of this document architecture is to support the exchange, processing and presentation of documents in open systems. ODA has been endorsed mainly by the computer industry, especially in Europe. 12.3.1 Details of ODA The main property of ODA is the distinction among content, logical structure and layout structure. This is in contrast to SGML where only a logical structure and the contents are defined. ODA also defines semantics. Following figure shows these three aspects linked to a document. One can imagine these aspects as three orthogonal views of the same document. Each of these views represent on aspect, together we get the actual document. The content of the document consists of Content Portions. These can be manipulated according to the corresponding medium.