IPT HSC 2017 - Multimedia Systems PDF

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HSC IPT Topic 4 (HSC Score 94)...

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IPT 2017 - Multimedia Systems Characteristics of Multimedia Systems Multimedia systems - information systems that include combinations of the following media, including: Text and numbers Text • •

Letters, numbers and other characters whose meaning/format is not specified until a user interprets it Inputted with a word processor

Hypertext • Enables user navigation (i.e. hyperlinks in the form of text) - linking individual documents/webpages • Each link specifies a location • Provides interactivity Numbers • Predefined characters (i.e. numerals) whose meaning/format is specified • Calculations can be performed on this data type

Audio • •

Sound that has been digitised Used to explain concepts, reinforce selections and provide special effects

Images and/or animations Images • Pictures, drawings, paintings or photographs • Used to create interest and provide info • Made up of pixels Bit-mapped graphics • Treats each pixel individually • When resized, can suffer loss of resolution • Aliasing: staircase pattern created when enlarging each pixel • Formats: GIF, JPEG Vector graphics • Made up of straight lines, curves etc. • Objects are defined by characteristics (e.g. position, width) • Characteristics are stored as mathematical expressions • Does not suffer loss of quality when resized • Formats: CGM, EPS and WMF

Animation • Movement of graphics - series of still images/frames displayed in rapid succession • Each frame is a cell • Can be more effective in the presentation of info compared to text and image

Video • • •

Combines images and sounds Starts with a continuous event which is separated into discrete frames Format: MPEG

Hyperlinks •

A highlighted item that enables electronic connection

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Can be in the form of text, image, audio, animation or video

Compare and contrast printed and multimedia versions with similar content The difference between print and multimedia, including: Different modes of display Print Media • Printed info is displayed using a printer/plotter Multimedia Screen • Display surface that provides immediate feedback • Can display text, image, animation and visual portion of video Speaker • Used to output sounds

Interactivity and involvement of participants in multimedia systems Print Media • Limited interactivity Multimedia • Interactivity: allows user to choose sequence and content of info • Interactive multimedia often responds to inputs from a touch screen, keyboard etc. • Hypermedia used for navigation and enhances interactivity of product

Ease of distribution Print Media • Hard copies can be scanned and shared or distributed by hand or post Multimedia • Easy to distribute via Internet (e.g. email)

Authority of document Print Media • There tends to be stricter enforcement on paper-based (i.e. hard copies) media Multimedia • Easier to share without respecting copyright/ownership

Summarise current information technology requirements for multimedia systems The demands placed on hardware by multimedia systems, including: Primary and secondary storage requirements as a result of: Bit depth and the representation of colour data • •

Bit Depth: number of bits per pixel Colour Graphics (or graphics with tones): increase the number of bits per pixel - requiring more storage

IPT 2017 - Multimedia Systems

File Size Calculation • Resolution x Bit depth

Sampling rates for audio data • • • •

Analog Data (sound waves): represented by continuous variable quantities Digital Data (digitised sound): represented in digits/numbers Analog-to-digital converter (ADC): creates audio Digital-to-analog (DAC): converts audio into sound

Sampling • Method used to digitise sound Sampling Rate • No. of times a sample is taken from the sound wave • The higher the sampling rate the higher the quality of the sound

Sample Size • No. of bits per sample • Common sampling sizes are 8-bit sound and 16-bit sound Mono Vs Stereo • Mono: uses one channel of sound • Stereo: uses two channels of sound (better sound)

File Size Calculation • (Sample rate x Sample size x time) x 2 (if stereo)

IPT 2017 - Multimedia Systems Processing as a result of: Video data and frame rates •

Frame Rate: speed of the video - measured by frames per second (fps) - higher the frame rate the higher the quality of the video

File Size Calculation • File size for video = No. of frames x file size for each frame • No. of frames = frame rate x time in seconds • File size for each frame = Resolution x Bit depth

Image processing, including morphing and distorting Morphing • Smooth change between two different images - transforming the shape, size, dimension or colour of the one image Warping • The transformation and distortion of a portion of an image

Distinguish between different approaches to animation including path-based and cell-based through practical investigations Animation processing, including tweening Cell-based animation • Involves drawing and displaying individual frames or cells - each frame stored separately • A fast processor and a large fast-access storage device to ensure animation flows at the appropriate speed Path-based animation • Displaying movement of objects onto a fixed background in a particular sequence or path • User creates first and last frame • Tweening: generation of the intermediate frames between two objects by the animation software

Display devices as a result of: Pixels and resolution • •

High resolution images require high resolution display devices A device with low resolution capacities cannot display high resolution images correctly

Describe the roles and skills of the people who design multimedia systems The variety of fields of expertise required in the development of multimedia applications, including: Content providers • • •

Provides material for multimedia product (e.g. text, graphic sketches, video footage, audio tracks) Does not require technical skills (i.e. software, hardware) E.g. Graphic Designers, video photographers, musicians

System designers and project managers System Designers • Responsible for the design of the final product • Organises content together

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Plans and organises navigation techniques Provide technical support E.g. User interface designers, instructional designers

Project Manager • Organises scheduling and supervises development • Ensures deadlines are met • Responsibilities include: o Scheduling o Team rostering o Allocation of tasks o Supervision of tasks o Budgeting o Organisation of team meetings o Documentation o Testing of final product

Those skilled in the collection and editing of each of the media types •

Usually content providers and artists contribute to the collection and editing of each media types

Those skilled in design and layout Design and Layout Personnel • Work to develop overall theme and look of the product

Those with technical skills to support the use of the information technology being used Technical Staff • Technicians edit graphic, video and text material into appropriate formats for the final document • Have expertise in hardware/software • Tests and produces final product

Identify multimedia software appropriate to manipulating particular types of data Text •

Microsoft Word

Images • Paint, Adobe Photoshop Audio • Audacity Video/Animation • Adobe Flash Professional • iMovie • Adobe Premiere

Examples of Multimedia Systems Discuss multimedia systems that address new technological developments The major areas of multimedia use, including: Education and training • • •

Multimedia systems are very effective in aiding the learning process Interactive nature - allows user to control their learning Cost-effective method - can be carried out at convenient times and can cater for a wide range of abilities

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Computer-based training (CBT): o Designed to cater for different rates of learning and are created by experts in the field o Users can review misunderstood concepts and are assessed before they are presented with the next level

Leisure and entertainment •

Usually computer games o Provide high level of interactivity o Feature high resolution images, audio and animation or video o Users usually use a controller for input

Information provision, such as information kiosk • •

User controls when, how and what info is displayed Interactive nature - enables user to search using related keywords

Information Kiosks • Users use a touch screen to select info • Commonly provide info about products/services and their location

Virtual reality and simulations such as flight simulator VR • • • • •

The use of computer modelling and simulation to enable a person to interact with an artificial environment Highly interactive Partial Immersion Systems: utilises a joystick, 3D mouse, 3D video card with a multimedia PC and special software Total Immersion Systems: when the participant is totally involved in the virtual reality environment VR immerses the user in the environment using interactive devices such as: o Goggles o Head-up displays o Gloves: equipped with force-feedback devices and provide sensation of touch o Body Suits o Motion Sensors: creates illusion of reality

Flight Simulators • Used to train pilots • External effects (e.g. changing weather conditions) require high-resolution images • Different scenarios can be modelled, and the reactions of the plane is created realistically

Combined areas such as educational games • •

Educational games are highly intuitive and interactive Effective way to engage young users in fun learning

Advances in technology which are influencing multimedia development Interpret developments that have led to multimedia on the World Wide Web •

Examples: o Faster processing - allowed to move at realistic speeds o Improvements in storage capacity - higher-quality images are available to be used in multimedia production o Advances in communication technology - allowed the sharing and displaying of multimedia via the Internet

World Wide Web • WWW - Internet network allowing users at one PC access to info at another • Web Site: group of documents that present info on a topic • Websites/webpages are stored on servers

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Highly interactive environment with hyperlinks connecting each webpage/site together

CD-ROM (compact disc with read-only memory) speed • 12 cm wide, capable of storing 650 Mb • Convenient for storing data that remains constant • Improvement of the speed of CD-ROM drives → faster retrieval of data DVD (digital versatile disk) • Stores large amounts of data • Produces studio-quality video and audio • DVD video stores video compressed (lossy) in MPEG-2 format • Major advantage of DVD is that text, image, video and audio have the same file structure (UDF - Universal Disc Format) overcoming issues of incompatibility

Identify participants, data/information and information technology for one example of a multimedia system from each of the major areas Education Participants • Teachers • Students Data/Information • Student performance • Educational content • Educational activities Information Technology • PC • Data projector • Touch Screen • GUI • Sound/Graphics Card • Interactive whiteboard

Leisure: Computer Games Participants • Gamers • Developers Data/Information • Game content (e.g. images, video, audio, animation, text) • Gamer details Information Technology • PC • Console (e.g. hand-held, controller) • Headset • Speaker • Controller • Screen, monitor • Graphics/video card • Sound Card • GUI

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Game application software

Information Kiosk Participants • Shoppers Data/Information • Information about shops or products • Directions to places Information technology • PC • Touch Screen • Kiosk • Screen • GUI

Flight Simulation Participants • Pilots in training Data/Information • Plane speed • Plane altitude • Pilot performance • Weather conditions Information Technology • PC • Large Screen • Head-up Display • Microphone • Speaker • GUI • Sound/Graphics card • Flight simulation software

Describe the relationships between participants, data/information and information technology for one example of a multimedia system from each of the major areas •

For all systems, the participants utilise information technology to manipulate data into information

Critically evaluate the effectiveness of a multimedia package within the context for which it has been designed Design Principles Consistency • Features such as layout, format and style should be as consistent as possible throughout the product • Readability is improved when similar items are grouped effectively which can be achieved by spacing, border etc. Navigation • Users need to be able to navigate/search for desired info • Short response time to a command/input is desirable for user satisfaction

IPT 2017 - Multimedia Systems Simple • Overuse of design elements → confusing/distracting

Media Text • Characters o Avoid using too many fonts o Care should be taken when using font styles such as bold and italic o Different size heading can be used to reflect order and importance o Lines of text should be succinct o A large font size is usually used in multimedia products • Screen Layout o Appropriate conventions are usually utilised for; • Column width • Alignment • Line spacing • Character spacing • Indentation • Hyphenation • Kerning o Bullets and numbering is a common way to organise text in a multimedia product • Text Colour o Colour contributes to the style and theme and draws audiences' attention to text o Some particular colours (such as red and blue) should not be used as they produce poor contrast and reduce readability o Too many colours can also reduce readability o A good colour scheme is vital to the professional appearance of a multimedia product. Images and Animations • Used to generate interest and provide info, however, places extra demands on the system (i.e. hardware/software) • Images/animations can be edited/adjusted to suit screen resolutions • Should be used in appropriate amounts and not too frequently • Titling: the placement of a caption to accompany an image or graphic element Audio and Video • Used to create interest and provide info • Should be used in appropriate amounts and not too frequently • Places extra demands on systems as audio and video files are large

Displaying in Multimedia Systems Describe how relevant hardware devices display multimedia and use a variety of devices Hardware for creating and displaying multimedia Screens • A display surface that provides immediate feedback of the processing of the CPU CRT (Cathode Ray Tube) • Produces images by firing a stream of electrons using an electron gun onto the inside of the screen which is coated with tiny dots or pixels made of phosphor • Colour monitors use 3 streams to strike red, green and blue phosphor • When the stream of electrons strikes the pixel, phosphor glows to produce the images • Cross Fade: The process by which the colour of a pixel changes gradually from its original colour to a new colour • Raster Scan: fires the electron stream in a series of zigzag lines

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Refreshing: repeating of the firing of the electron stream to maintain the image as phosphor only glows for a short time Interlaced monitors: speeds up the refreshing process by scanning the odd lines first then the odd lines causes flickering of the monitor Non-interlaced monitors: refresh the screen by scanning every line 72 times/sec Delta Information (i.e. change info): information that describes the difference between the two screens (after altercation of the screen occurs) Vector display systems: a special type of CRT display that only displays vector graphics o Directs electron stream to only draw the lines required for the image o Faster refresh rate than CRT displays (raster scan) Advantages: o Cheap Disadvantages: o Heavy o Lower quality compared to LCD, Plasma, LED

LCDs (liquid crystal displays) • Flat screen - consist of a layer of liquid crystal placed between two polarising sheets/glass panels, light is passed through the layer and a current is applied at display points • Transparent electrodes electrify the crystals to change its direction/position to create the image • Separate transistor controls the light allowed to pass through each pixel by varying the voltage • Can display brilliant colour and high image quality • Used in portable devices • More expensive than CRTs • Advantages: o Lightweight o Takes up less physical space o Produces no heat o No glare o No radiation o Requires less power than CRT - LCDs can run on batteries o Unlimited colours and native resolution • Disadvantages: o LCDs are volatile - easily damaged by external shocks o Smaller viewing angle o Increasing the size may increase chances of bad resistors LEDs • A flat panel display - uses an array of light emitting diodes as pixels for a video display

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Light-emitting diode (LED): is a semi-conductor device that emits light when an electric current is passed through it How is light emitted from a diode? o When an electric current is passed through the diode → electrons rush towards the +ve side of the battery → falls into the holes o When the electron falls → loses energy in the form of a photon (i.e. light particle) → emitting light

How are LEDs used in visual displays? o Seven-segment displays: used to form illuminated characters in devices such as calculators o Used in outdoor visual displays (e.g. billboards) o Used as backlight in an LCD screen o Used in stage lighting as well as decorations Advantages: o High brightness - can be used under sunlight o Wider viewing angle o Can produce dynamic colour o Automatic temperature control o Lightweight o Low power and energy efficient o Does not emit heat/radiation o Can be recycled/reused o Long lifetime of 50,000 hours o Difficult to damage with external shocks o No warm-up period o Excellent colour rendering - i.e. does not wash out colours Disadvantages: o More expensive than CRTs or LCDs o Must be supplied with constant voltage o Shifts colour after aging o Prone to overheating if not manufactured/engineered correctly → device failure

Plasma Displays • Function: o Images displayed from plasma screens consists of an array of red, green and blue pixels o Plasma: an ionisation of gas caused by the striking of an electric arc which results in a white light being emanated by the ionised gas o Thousands of tiny cells (pixels) are placed between two plates of conductors, these cells are activated when there is an electric current that strikes the cells, ionizing the gas inside them. o The cells turn red/blue/green according to the colour of the phosphors they are coated with. • Characteristics: o Plasma displays can be made up to large sizes like 150 inches diagonal o Very low-luminance "dark room" black level o Very high contrast o Life-time of almost 100,000 hours • Advantages:

IPT 2017 - Multimedia Systems

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o Has better viewing angles than LCD o Produces richer natural colours due to light leakage o Does not have motion blur due to high refresh rates and response times o Slimmest display o Large screen availability o Lightweight o Can be placed on walls o High clarity and better colour reproduction o Smooth p...