Modern Multimedia• Good Multimedia combines media elements to communicate MORE effectively than traditional media types
Characteristics of Multimedia that make it more effective in communicating• It caters to different learning styles as some people learn better from listening, or seeing or reading.• Good multimedia will combine these or let the user choose the form of instruction.• Good multimedia will engage the user by letting them choose the topic or area of interest directly.
Cont.• Multimedia allows learners to choose the level of difficulty that suits them best, unlike a book or a teacher who must teach to 1 audience.• It allows learners to choose the pace of instruction –fast for strong learners, slow for those having difficulty.• It allows the repeating of information as many times as necessary for learners having difficulty
Consistency Users expect that different applications will have a sameness to them which means knowledge is transferable to a similar product. Ie Disk symbol means save on most programs• Also consistency is when buttons are in the same place from page to page or form to form.
Feedback• Feedback describes elements that gives the user a response. Example: buttons clicked make noises. A progress bar showing how long until a process is completed.
Forgiveness• High forgiveness allows users to undo mistakes or undo previous decisions in a program. All actions should be reversible.
AestheticsAesthetics means its level of attractiveness. Good multimedia should:• Have adequate amounts of whitespace (clean interface)• Not use too many fonts (confusing to reader)• Should not have overly bright or harsh colors (hurts eyes)
Social and Ethical Issues• Copyright• Piracy• Changing nature of work
Storyboards help us design and document Multimedia
The main theme• The option topic is about how multimedia can be used to communicate more effectively in the area:• Education /Training• Entertainment – Film and Television, Virtual Reality.• Business – Take a virtual tour of a house.• Emerging Technologies – LED TVs / 3D TV » Digital TV » IPhones » Enhanced Reality
Vocabulary of Multimedia• Enhance –to raise to a higher degree; intensify; magnify: Video and Audio enhanced the students learning
Synergy• Synergy - the cooperative action of two or more elements for greater effect than either alone.• Example: “The effect of Multimedia is one of synergy. Video and Text together create a more powerful learning/entertainment/business impact than each shown by themselves.”
Engage• to occupy the attention or efforts of (a person or persons): “The video, voice narration and then interactive test engaged the student…”
Interact• Interact: To act on each other• Interactive multimedia means the user and program act upon the other. Both are active processes.
Vector GraphicsVector graphics use mathematical Formulas to store graphic data This line might be stored as A3:F3 Only 2 points need to be remembered and stored on the HDD. When it is on your screen however it must be displayed as pixels
Vector Graphics• These coordinates or “vectors” are known as “primitives”. When stored on disk they are referred to as primitives as they are not formed yet.
Vector graphics• As co-ordinates only need to be remembered, less space is needed in storage.• You can blow up pictures as large as required without distortion or loss of info• Because of this it is perfect for plan diagrams such as blueprints, and technical specifications.• It is the graphics used in Computer Aided Design or (CAD)• Vector graphics can easily be changed.• If the program is called “*” Draw – It is a vector graphics program. “*” Paint is bitmap
Frame Buffer• The frame buffer or Video Ram is an area of very fast memory that contains the bitmap image of the current screen display• Still pictures and movies must be displayed Memory Chip
Monitor Frame buffermirrors exactlythe contentsof the frame Frame buffer or VRAM contains the bitmap imagebuffer with the details of each pixel Each pixel and its location needs to be stored on your HDD
The Frame Buffer and Image size BIT DEPTH Relationships Number of Colors 1 2 1 2 2 2 2 4 3 2 3 8 4 2 4 16 8 2 8 256 16 (high color) 2 16 65536 24 (true color) 2 24 16777216
The Frame buffer and Image size• Resolution is measured by the number of pixels per inch Each Square is the same size but the one with the most dots has higher resolution High Low
Jaggies or Resolution & Bitmaps stepsBitmaps distort and lose aspect ratio(relationship between the width and theheight of an image ) unlike vectorgraphics If you enlarge a bitmap image too much it pixelates or has jaggies
Anti-AliasingAnti-Aliasing is one of the most important techniques inmaking graphics and text easy to read and pleasing to the eye on-screen isanti-aliasing. Anti-aliasing is a cheaty way of getting round the low72dpi resolution of the computer monitor and making objects appear as smooth No Anti-Aliasing Anti-Aliasing
How it worksWhen the computer anti-aliases the line it works out how much ofeach in-between pixel would be covered by the diagonal line anddraws that pixel as an intermediate shade between backgroundand foreground
DitheringDitheringDithering is the process of “mixing” pixels of two colors tocreate the illusion that a third color is present.Full-color photographs may contain an almost infinite range ofcolor values. Dithering is the most common means ofreducing the color range of images down to the 256 (orfewer) colors seen in 8-bit GIF images.Example: An image with only black and white in the colorpalette. By combining black and white pixels we can creategrey
How to calculate image size 800 pixels Bit plane is set At 24 bits600 pixels
How to calculate the size• Calculate the number of pixels and Multiply pixels by bit depth / bit plane600 x 800 x 24 = 11 520 000 bits• Calculate the number of bytes by dividing total bits by 8 800 pixels11 520 000 / 8 = 1440 000 bytes• Calculate the number of kilobytes by dividing by 1024 Bit plane set at 24 bits 600 pixels 1440 000 /1024 = 1406kbCalculate the number of megabytes by dividing by 1024 since there are 1024 kb in a megabyte 1406 / 1024 = 1. 44mb (rounded up to the nearest mb)
How to calculate the time needed to download or upload the file USING A 56KB/S MODEM @ 200BITS PER SECOND• Formula is Size of file / total amount transferred per second 800 pixels600 x 800 x 24 = 11 520 000 bits11 520 000 / 200 bits per sec= 57600 seconds (Number of seconds to transfer) Bit plane set at 24 bits 600 pixels57600 / 60 seconds = 960 minutes960 minutes / 60 minutes = 16 hours
Things to think aboutWhy is file size important when designing your webpage?Should you choose 16 bit color or 24 bit color?How can we reduce the amount of memory required for graphics?Reduce bit plane (Dithering Does this)Reduce resolution of graphic thereby reducing the number of pixels
Charged coupled device (CCD) converts light into digital data or converts digital data into light Video Firewire card USB Analogue Digital movie capture file can now be card editedCapture digital data from digital video cameraIf it is an analogue camera, a video capture card is needed tosample the analogue data
Codec Firewire card USB Codec Analogue capture Digital movie file can now card be edited• Coder-decoder." A device or software application that converts analogue video and audio signals into a digital format for transmission. Also converts received digital signals back into analogue format.
Video Compression Example Mpeg or Divx• Frames are analysed and section of the frames are analysed.• If sections within frames are the same such as a car coming down the road. Repeated elements such as trees are taken out. They are replaced upon decompression.
Video CompressionLarge file sizes of video means compression is often used.2 types of compression are:Lossy – Data is lost or shed for the sake of file size. This may be bitdepth ( number of colors) resolution, sound (stereo to mono)Lossless – A type of compression that reduces data without sheddinginformation- Example: A word document is compressed. Spaces arecounted and then deleted. When uncompressed the spaces are putback. The number common vowels may be counted and thenremoved and then replaced by the program after decompression.
SamplingTo Sample: “To take portions from the whole to make arepresentative of the whole”
Illustration of Sampling Analogue Soundwave Digitally sampled Soundwave
MICROPHONEHow to sample a sound or digitally convert it from analogue to digital ADC 000100100101101010101000 COMPUTER MEMORY 000100100101101010101000 DAC SPE
MICROPHONE Sampling ADC 01000 0001001001011010101 COMPUTER MEMORY DAC 01000 0001001001011010101 SPEAKERReal World Analogue signals are converted to “0”s and “1s”Not all the sound information is recorded. Only important samples along the analogue wave.What is useful? –Only what humans actually hear
Digital AudioThe type, size of the file and quality of digital audio depends on 3 elements:1. Frequency (11 khz, 22 khz or 44 khz)2. Mono / Stereo3. Resolution: bit size of the samplings
SummaryIn general, the following rules apply:Frequency – The higher the rate, the better the sampling qualityMono/Stereo – 1 (mono) or 2 (Stereo) channels create depth of sound butneeds more memoryResolution – More bits sampled 8 vs 16 means greater accuracy
How to Calculate Digital File Sizing Audio video Audio and video
Advantages of digitalised sound Can be transported electronically or over a network (itunes) Can be manipulated electronically I.e affects added Can combine sounds and instruments to create a whole orchestra Can be copied easily DRM can be applied Can be indexed and databased for access Can be easily stored on hard drive and other media Can be compressed
M.I.D.IMusical Instruments Digital Interface MIDI (Musical Instrument Digital Interface, pronounced / ˈmɪdi/) is an industry-standard protocol that enables electronic musical instruments such as keyboard controllers, computers, and other electronic equipment to communicate, control, and synchronize with each other. MIDI allows computers, synthesizers, MIDI controllers, sound cards, samplers and drum machines to control one another, and to exchange system data. MIDI data files are very small and are often used as website background music
How to calculate size of uncompressed videoCalculate the size of a video file 10 seconds long at 5frames per second, 50 pixels high and 50 pixels wide with abit depth of 8bits. Express in bytes 5 frames x 10 sec x (50 x50 x 8 ) / 8 = total uncompressed size
Cell based animationCell based animation is when picture movement is drawn orcreated a little bit different each time. When viewed in quicksuccession it appears to move. This is the traditional method thatDisney used on transparent pieces of cellulose, hence “cells”•Each picture is a frame or a cell•Each one is drawn individually and requires memory storage
Cel Based Animation Cont. Notice the picture of the sun. Each frame consists of a background and a “sprite/s” that move
Path Based AnimationPath based animation relies on the computer program to do most of the work. The artist specifies the “path” for each moving object. Key pointsare specified and then the program calculates what changes are needed between points Bang Key point SpriteKey point Key point
Computer Fills the gaps between key points of the animation Bang Key point Sprites Key pointKey point
Path Based Animation cont.• This use of key points in which the computer generates everything that goes between points is also known as “tweening”.
Morphing• Morphing is when 1 object changes to another. Example: A man turning into a lion In this example, it is one person turning into another person
WarpingWarping should never be confused with Morphing. Warping is when theoriginal image is distorted, and twisted about
Digital Rights Management• Technology designed to prevent the copying and distribution of digital media.Itunes. Prevents the moving of songs from one machine to the other.Youtubes forthcoming digital fingerprinting.Digital fingerprinting technology is when media is tagged so that if it is uploaded, it is instantly recognised as copyrighted material and automatically deleted.Big pond movies – Media will only be playable for a given amount of time.
How MP3s Work• MP3 algorithms compress a digital sound file to a much smaller size.• Compression Algorithms are used to reduce the size of the file using “lossy”• An compression algorithm is a set of instructions that process the sound file to reduce it using a set of criteria.
How it works• To make a good compression algorithm for sound, a technique called perceptual noise shaping is used. Its "perceptual" partly because the MP3 format uses characteristics of the human ear to design the compression algorithm.
What the algorithm looks for to leave out or emphasise• certain sounds that the human ear cannot hear.• certain sounds that the human ear hears much better than others.• If there are two sounds playing simultaneously, we hear the louder one but cannot hear the softer one.
MP3• certain parts of a song can be eliminated without significantly hurting the quality of the song for the listener.• Compressing the rest of the song with well- known compression techniques shrinks the song considerably -- by a factor of 10 at least. When youre done creating an MP3 file, what you have is a "near-CD-quality" song. The MP3 version of the song does not sound exactly the same as the original CD song because some of it has been removed.
How Film Compression works• Files such as DivX, Mpeg and .AVI have been reduced using the following methods:• Reduce the number of frames per second.• Reduce the sampling rate and size of the audio• Removing from the video parts of the image that were already shown. Example: in a video where there is one person talking and that this person is not moving. On the first frame the image is shown complete, but on the second frame the parts of the image that are identical to the first frame are removed from the image. If only the mouth of the person is moving, only the area around the mouth will be drawn on the second frame.
Multimedia Types• Text – includes words and numbers and special characters such as #@$.• Hypertext / Hyperlink – Clickable text that links to a URL (universal Resource Locator) in the format of a www.domainname.com or file location.• Hypermedia- Is clickable media other than text. Example: we can click on a photo or animated gif. It will link to a URL or file much the same way as a hyperlink.• Streaming video – Video which is sent over a network using UDP protocols to be played on embedded video players on a browser.• Whitespace – The area of a webpage left white. Too much clutter confuses the user and inhibits communication. The correct amount of whitespace will direct user focus.
New Technologies used to share information via Multimedia• RSS – Real Simple Syndication is a method by which information is published to users to keep them updated. A user elects to accept a RSS feed in their browser.• Share features like Digg allow user ratings of web content. Higher ratings result in a higher profile of the content in the Internet community. (User interactivity)• Twitter – information and opinion sharing forum that played a prominent part in showing what happened in Iran this year.• Youtube – Video Streaming
Convergence• Convergence describes the coming together of technologies to form a new one that is more powerful in its ability to communicate.• Example – Camera / Phone » Camera /Phone/Computer » Watch / GPS » Video camera /GPS