Multimedia: CH#1 is any combination of text, art, sound, animation, and video delivered to you by computer or other electronic or digitally manipulated means. Definitions: When you allow an end user also known as the viewer of a multimedia project to control what and when the elements are delivered, it is called interactive multimedia. interactive multimedia becomes hypermedia. The software vehicle, the messages, and the content presented on a computer, television screen together constitute a multimedia project. Shipped or sold to consumers or end users typically in a box or sleeve or on the internet with or without instruction it is Multimedia title. linear, or starting at the beginning and running through to the end. When users are given navigational control, and can wander through the content at will, multimedia becomes nonlinear and user interactive, and is a powerful personal gateway to information. Multimedia elements are typically sewn together into a project using authoring tools. The sum of what gets played back and how it is presented to the viewer on a monitor is the graphical user interface, or GUI (pronounced gooey ). Where to Use Multimedia? 1. Multimedia in Business. 2. Multimedia in Schools. 3. Multimedia at Home. 4. Multimedia in Public Places. 5. Virtual Reality
Virtual Reality: 1. 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. 2. 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 3. On the World Wide Web, standards for transmitting virtual reality worlds or scenes in VRML (Virtual Reality Modeling Language) documents (with the filename extension. wry) 4. Using high-speed dedicated computers, multi-million-dollar flight simulators built by Singer, Refusion, and others have led the way in commercial application of VR 5. Virtual reality (VR) is an extension of multimedia and it uses the basic multimedia elements of imagery, sound, and animation. Text: CH#2 Using text and symbols for communication is a very recent human development that began about 6,000 years ago. In some former eras it was a capital offense to read unless you belonged to the proper social class or possessed a patent granted to you by your rulers. Today, text and the ability to read it are doorways to power and knowledge. Reading and writing are expected. Text still delivers information that can have potent meaning. About Fonts and Faces: A typeface is a 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 typeface family. Point is a 0.0138 inch, or about 1/72 of an inch.
Computer fonts automatically add space below the descender (and sometimes above) to provide appropriate line spacing, or leading. Kerning is the spacing between character pairs. WYSIWYG is more of a goal than an absolute fact. The Extended Character Set: A byte, which consists of 8 bits, is the most commonly used building block for computer processing. ASCII uses only seven bits to code its 128 characters; the eighth bit of the byte is unused. This extra bit allows another 128 characters. Unicode: The original standard accommodated up to about 65,000 characters to include the characters from all known languages and alphabets in the world. Scripts: The shared symbols of each language are unified into collections of symbols (called scripts). Mapping Text Across Platforms: If you build your multimedia project on a Windows platform and play it back on a Macintosh platform (or vice versa), there will be subtle (and sometimes not-so-subtle) differences. substitute must be provided that does exist on the target. This is font substitution. Localization: Translating or designing multimedia (or any computer-based material) into a language other than the one in which it was originally written is called localization Jaggies: are avoided by anti-aliasing the edges of the text characters, making them seem smoother to the eye.
Hypermedia and Hypertext: Multimedia the combination of text, graphic, and audio elements into a single collection or presentation. Interactive multimedia becomes hypermedia when its designer provides a structure of linked elements through which a user can navigate and interact. When a hypermedia project includes large amounts of text or symbolic content, this content can be indexed, and its elements then linked together to afford rapid electronic retrieval of the associated information. When words are keyed or indexed to other words, you have a hypertext system. When text is stored in a computer instead of on printed pages, the computer s powerful processing capabilities can be applied to make the text more accessible and meaningful. The text can then be called hypertext. Searching for Words: Following are typical methods for word searching in hypermedia systems: 1. Categories Selecting or limiting the documents, pages, or fields of text within which to search for a word or words. 2. Word relationships Searching for words according to their general proximity and order. For example, you might search for party and beer only when they occur on the same page or in the same paragraph 3. Adjacency Searching for words occurring next to one another, usually in phrases and proper names. For instance, find widow only when black is the preceding adjacent word. 4. Alternates Applying an OR criterion to search for two or more words, such as bacon or eggs.
5. Association Applying an AND criterion to search for two or more words, such as skiff, tender, dinghy, and rowboat. 6. Negation Applying a NOT criterion to search exclusively for references to a word that are not associated with the word. For example, find all occurrences of paste when library is not present in the same sentence. Hypermedia Structures Links are connections between the conceptual elements, nodes, which may consist of text, graphics, sounds, or related information in the knowledge base. A typical navigation structure might look like the following:
Hypertext Tools: Two functions are common to most hypermedia text management systems, and they are often provided as separate applications: building (or authoring) and reading. The builder creates the links, identifies nodes, and generates the all-important index of words. search algorithms used to find, and group words optimized for performance finding search words among a list of many tens of thousands of words requires speed-demon programming. Before you start to create Images: 1. Plan Your Approach 2. Organize Your Tools 3. Multiple Monitors Making Still Images: CH#3 still images are generated by the computer in two ways: as bitmaps (or paint graphics) and as vector-drawn (or just plain drawn ) graphics. - Bitmaps are used for photo-realistic images and for complex drawings 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. - Typically, image files are compressed to save memory and disk space; many bitmap image file formats already use compression within the file itself for example, GIF, JPEG, and PNG. Bitmaps: - A bit is the simplest element in the digital world, an electronic digit that is either on or off, black or white, or true (1) or false (0). This is referred to as binary, since only two states (on or off) are available. A map is a twodimensional matrix of these bits. A bitmap, then, is a simple matrix of the tiny dots that form an image and are displayed on a computer screen or printed.
- These picture elements (known as pels or, more commonly, pixels) can be either on or off, as in the 1-bit bitmap, or, by using more bits to describe them, can represent varying shades of color (4 bits for 16 colors; 8 bits for 256 colors. Capturing and Editing Images: As you assemble images for your multimedia project you may often need to capture and store an image directly from your screen. Morphing: is another effect that can be used to manipulate still images or to create interesting and often bizarre animated transformations? Morphing allows you to smoothly blend two images so that one image seems to melt into the next. Vector Drawing: vector-drawn objects such as lines, rectangles, ovals, polygons, complex drawings created from those objects, and text. - Computer-aided design (CAD) programs have traditionally used vectordrawn object systems for creating the highly complex and geometric renderings needed by architects and engineers. - Graphic artists designing for print media use vector-drawn objects so eliminated jaggies (without jaggies). - Programs for 3-D animation also use vector-drawn graphics. For example, the various changes of position, rotation, and shading.
Vector-Drawn Objects vs. Bitmaps: 1. 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. 2. web pages that use vector graphics in plug-ins such as Flash download faster and, when used for animation, draw faster than pages displaying bitmaps. 3. vector objects are easily scalable without loss of resolution or image quality. Resizing a bitmapped image requires either duplicating pixels (creating a blocky, jagged look called pixilation) or throwing pixels away. Converting Between Bitmaps and Drawn Images: Converting bitmaps to drawn objects is more difficult. There are, however, programs and utilities that will compute the bounds of a bitmapped image or the shapes of colors within an image and then derive the polygon object that describes the image. This procedure is called autotracing. 3-D Drawing and Rendering: - Drawing in perspective or in 3-D on a 2-D surface take special skill and talent. - A great of information is needed to display a 3-D scene. Scenes consist of objects. - Objects and elements in 3-D space carry with them properties such as shape, color, texture, shading, and location. - When you lathe a shape, a profile of the shape is rotated around a defined axis (you can set the direction) to create the 3-D object. - Once you have created a 3-D object you can apply textures and colors to it to make it seem more realistic rough and coarse or shiny and smooth. - Shading can usually be applied in several ways.
- Rendering is when the computer finally uses intricate algorithms to apply the affects you have specified on the objects you have created. Color: Is a vital component of multimedia. Understanding natural Light and Color: - Light come from an atom when an electron passes from a highet to a lower energy level; This explanation of Hight, known as the quantum theory. - Color is the frequency of a light wave within the narrow band of the electromagnetic spectrum to which the human eye responds. Additive and Subtractive color: Additive color: Is created by combining colored light source in three primary colors: red, green, and blue(rgb). This is the process used for a TV or computer monitor. On the back of the glass face of a monitor are thousands of phosphorescing chemical dots. These dots are bombarded by electrons that paint the screen at high speeds. The red, green, and blue dots light up when hit by the electron beam.
Example: Subtractive Color: In the subtractive color method, color is created by combining colored media such as paints or ink. Subtractive color is the process used to create color in printing. The printed page is made up of tiny halftone dots of three primary colors: cyan, magenta, and yellow (designated as CMY). Four-color printing includes black. Example:
Computer Color Models: The color of a pixel on your computer monitor is typically expressed as an amount of red, green, and blue. Color Palettes: Are mathematical tables that define the color of a pixel displayed on the screen. Dithering: is a process whereby the color value of each pixel is changed to the closest matching color value in the target palette using a mathematical algorithm. Acoustics: CH#4 Is the branch of physics that studies sound. Decibels(dB): Sound pressure levels are measured in decibels(db): Digital Audio: Digital Audio is created when your covert a sound wave into numbers a process referred to as digitizing. You can digitize sound from a microphone a synthesizer existing tape recordings live radio and television broadcasts and popular CDs. In fact, you can digitize sounds from any source natural or prerecorded. Every nth fraction of a second a sample of sound is taken and stored as digital information in bits and bytes. Sampling rate or frequency, measured in kilohertz, or thousands of samples per second) how many numbers are used to represent the value of each sample. Quantizing and Clipping Quantization The value of each sample is rounded off to the nearest integer (quantization), Quantization can produce an unwanted background hissing noise
Clipping if the amplitude is greater than the intervals available, clipping of the top and bottom of the wave occurs. clipping may severely distort the sound. Calculate the size of a mono recorded audio file of sampling rate at 22.05 khz, 16-bit resolution for 10 seconds. sampling rate * duration of recording in seconds * (bit resolution / 8) * 1 = 22.050 * 1000 = 22050 = 22050 * 10(8/8) * 1 = 22050 * 10 * 1 * 1 = 22050 * 10 = 220500 bytes Calculate the size of a stereo-recorded audio file of sampling rate at 44.1 khz, 16-bit resolution for 10 seconds. sampling rate * duration of recording in seconds * (bit resolution / 8) * 2 = 44.1 * 1000 = 44100 = 44100 * 10 (16/8) * 2 = 44100 * 10 * 2 * 2 = 44100.000 * 4 = 17640.000 bytes
Making MIDI Audio: MIDI (Musical Instrument Digital Interface) is the quickest, easiest, and most flexible tool for this task. Yet creating an original MIDI score is hard work. Knowing something about music, being able to play the piano, and having a lot of good ideas are just the prerequisites to building a good score; beyond that it takes time and musical skill to work with MIDI. The process of creating MIDI music is quite different from digitizing existing audio. To make MIDI scores, however, you will need sequencer software and sound synthesizer (typically built into the sound board on PCs, but an ass-on board or peripheral for the Macintosh) A MIDI Keyboard is also useful to simplify the creation of musical scores. Audio File Formats: 1. CD-ROM/XA. 2. AIFF. 3. AIFC. 4. MACE. 5. WAY. MIDI has several advantages over digital audio and two huge disadvantages. The Advantages: 1. MIDI files are much more compact than digital audio files and the size of a MIDI file is completely independent of playback quality. 2. Because they are small MIDI file embedded in web pages load and play more quickly than their digital equivalents. 3. In some cases, if the MIDI sound source you are using is of high quality MIDI files may sound better then digital audio files. Now for disadvantages: 1. Because MIDI data does not represent sound but musical instruments you can be certain that t playback will be accurate only if the MIDI playback device is identical to the device used for production.
2. Also, MIDI cannot easily be used to play back spoken dialog although expensive and technically tricky digital samplers are available. The Power of Motion: CH#5 Visual effects such as wipes, fades, zooms, and dissolves are available in most authoring packages, and some of these can be used for primitive animation. But animation is more than wipes, fades, and zooms. Animation is an object actually moving across or into or out of the screen a spinning globe of our earth. Principles of animation: complete a perceived action, this makes it possible for a series of images are changed very slightly and very rapidly, one after the other, to seemingly blend together into a visual illusion of movement. Television video & Movies on film: Television video Movies on film 30 entire frames or pictures every Shot at a shutter rate of 24 frames second per second 48 times per second You have motion and animation cel animation: Cel animation artwork begins with keyframes; these are the first and last frames of an action.
keyframes and Tweening: The series of frames in between the keyframes are drawn in a process called tweening. Tweening is an action that requires calculating the number of frames between keyframes and the path the action takes. Computer animation: programs typically employ the same logic and procedural concepts as cel animation and use the vocabulary of classic Cel animation terms such as layer keyframe and tweening. Jerky animation: Moni tor within say 1/15 the of a second then the animation may appear jerky and slow. Kinematics: is the study of the movement and motion of structures that have joints, such as a walking man. Inverse kinematics: available in high-end 3-D programs such as Light wave and Maya. Morphing: is a popular (if not overused) effect in which one image transforms into another. Animation File Formats: Flash files(.swf) in order to play on the web. Audio video interleaved format (.avi) Quick Time (.qt,.mov). Motion Picture Engineering Group video (.mpeg or.mpg)
Making Animation That Work: Use animation carefully and sparingly to achieve the greatest impact. Your screens will otherwise become busy and noisy. 1. A Rolling Ball: Create a new layer in photoshop the center of the image. 2. A Bouncing Ball: The individual frames the make up the animation GIF. Obtaining Video Clips: CH#6 There are many sources for film and video clips in cost and time. But rights may be difficult How Video Works: A charge-coupled device (CCD) converts the light that has been reflected from an object through the camera's lens. analog recording: The video signal is written to tape by a spinning recording head that changes the local magnetic properties of the tape's surface in a series of long diagonal stripes. Because the head is tilted at a slight angle compared with the path of the tape,it following a helical(spiral)path which is called helical scan recording.
Broadcast Video Standards: 1. NTSC 2. PAL 3. SECAM 4. ATSC DTV NTSC: National Television Standards Committee (NTSC). As specified by the NTSC standard, a single frame of video was 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 was used in the United Kingdom, Western Europe, Australia, South Africa, China, and South America. PAL increased the screen resolution to 625 horizontal lines, but slowed the scan rate to 25 frames per second. taking 1/50 of a second to draw (50 Hz). SECAM: SECAM is a 625-line, 50 Hz system, it differed greatly from both the NTSC and the PAL color systems in its basic technology and broadcast method.
ATSC DTV: - TV stations with sufficient bandwidth to present four or five standard television signals. - HDTV signal (providing 1,080 lines of resolution with a movie screens 16:9 aspect ratio). Analog Video: Overscan and the Safe Title Area: It is common practice in the television industry to broadcast an image larger than will fit on a standard TV screen so that the edge of the image seen by a viewer is always bounded by the TV`s physical frame or bezel.this is called overscan. In contrast, computer monitors display a smaller image on the monitor s picture tube(underscan). Video Color: - Color reproduction and display is different between television and computer monitors. - They spilt colors into red, green, and blue signal, their colors are purer and more accurate than those seen on a television set that is using a composite input. - Indeed, NTSC television uses a limited color palette and restricted luminance (brightness) levels and black levels.
Text and Titles for Television: Here are some suggestions for creating good titles: Fonts for titles should be plain, sans serif, and bold enough to be easily read. Onto a dark background, use white or a light color for the text. Never use black or colored text on a white background. always make your lines at least two pixels wide. Use them, draw them large and with thick lines. Avoid colors that are too hot Keep your graphics and titles within the safe area of the screen. Remember that televisions overscan computer output. Avoid making busy title screens; use more pages instead. Digital Video: In camera and on computers eliminates the analog television form of video from both the multimedia production and the delivery platform. Digital Video Architectures: A digital video architecture is made up of a format for encoding and playing back video files by a computer and includes player that can recognize, and play files created for that format. Digital Video Compression: Digital video compression schemes or codecs (coders/decoders). A codec is the algoritm used to compress(code) a video for delivery. Decode it in real-time for fast playback. Example: CD-ROM or Web o MPEG: (Moving Picture Experts Group) MPEG-1 MPEG-2 MPEG-4 MPEG-7
Video Recording and Tape Formats: - Composite analog video Composite video combines the luminance and Chroma information from the video signal. As a result, it produces the lowest quality video and is most susceptible to generation loss, the loss of quality that occurs as you move from original footage to edit master to copy. This recording format was used for consumer analog video. - Component analog video Component video separates the luminance and Chroma information in order to improve the quality of the video and to decrease generation loss. This is he level for "prosumer" industrial and professional video equipment. As mentioned earlier, there are different methods of separating the signals, producing quality within this category. * S-video: In S-video color and luminance information are kept on two separate track (Y/C). The result is a definite improvement in picture quality over composite video. This standard is used in S-VHS and Hi-8. - Composite Digital: The recording formats combine the luminance and chroma information, just as analog composite formats do but they sample the incoming waveforme and encode the information in binary (0/1) digital code. It improves color and image resolution. Eliminates generation loss. - Component digital Adds that advantages of component signals to digital recording. Sony released the first equipment in this category with its D-1 format. Has a very high-quality image.
Shooting and Editing Video: Shooting Platform: 1. A steady shooting platform. 2. Try to use a camera with an electronic image 3. Use camera move and moving subject mask your lack of steadiness Lighting: 1. Difference between professional camcorders and consumer camcorders. 2. Using a simple floodlight kit 3. Improve your image onboard. Chroma Keys: 1. A useful tool easily implemented in most digital video editing application is blue screen, green screen, Ultimate, or chroma key editing. 2. Blue screen is a popular technique for making multimedia titles. Composition: 1. Use close-up and medium shots, head-and-shoulders or even tighter. Optimizing Video Files for CD-ROM: Limit the amount of synchronization required between the video and audio. Quick Time files you should flatten Flattening: interleave the audio and video segments together. Use regularly spaced key frames, 10 to 15 frames apart, and temporal compression can correct for seek time delays. In Quick Time, 20 frames per second. Software compression algorithm you specify will make a dramatic difference in performance. Quick Time is optimized for CD-ROM playback. Consider using a specialized application such as Media Cleaner.
CH#7 The Stages of a project: 1. Planning and costing: A project always begins with an idea or a need that you refine by outlining its messages and objective. - Develop a creative graphic look and feel. - Work up a short prototype or proof-of-concept 2. Designing and producing: Perform each of the planned tasks to create a finished product. 3. Testing: Test your programs to make sure that they meet the objectives of your project. 4. Delivering: Package and deliver the project to the end user. Types of Authoring Tools: 1. Card-or page-based tools 2. Icon-based, event-driven tools 3. Time-based tools Card- and Page-Based Tools: Card-based or page-based tools are authoring systems, wherein the elements are organized as pages of a book or a stack of cards. Thousands of pages or cards may be available in the book or stack. Icon-based, event-driven tools: Icon- or object-based, event-driven tools are authoring systems, wherein multimedia elements and interaction cues (events) are organized as objects in a structural framework or process. display flow diagrams.
Time-Based Tools Time-based tools are authoring systems, wherein elements and events are organized along a timeline, with resolutions as high as or higher than1/30 second. Time-based tools are best to use when you have a message with a beginning and an end. Sequentially organized graphic frames are played back at a speed that you can set. Authoring Tools features: 1. Editing Features. 2. Organizing Features. 3. Programming Features. 4. Interactivity Features. 5. Performance Tuning Features. 6. Playback Features. 7. Delivery Features. Time Based Authoring Tools: Director: Is a powerful and complex multimedia authoring tool. - Cast: The Cast is a multimedia database containing still images, sound files, text, palettes, Quick Draw shapes, Programming scripts, Quick Time movies, Flash movies, and even other director files.
- Score These Cast members together using the Score facility. - Lingo Director utilizes Lingo, full-featured object-oriented scripting language, to enable interactivity and programmed control.