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  • 1. Graphics and Multimedia

2. Multi-Media Multi Media describes several forms ofmedia which combine to communicatemore effectively than they wouldseparately. Example text and filmPhotos and Sound. 3. Why is Multimedia better thanTraditional Media Traditional media could be defined as: Books /Magazines /Audio /Video 4. People would learn by:Reading Books or Magazines 5. Watching TV or Movies 6. Listening to Audio 7. Or even a combination of several 8. Modern Multimedia Good Multimedia combines mediaelements to communicate MOREeffectively than traditional media types 9. Characteristics of Multimedia that make itmore effective in communicating It caters to different learning styles assome people learn better from listening, orseeing or reading. Good multimedia will combine these or letthe user choose the form of instruction. Good multimedia will engage the user byletting them choose the topic or area ofinterest directly. 10. Cont. Multimedia allows learners to choose the level ofdifficulty that suits them best, unlike a book or ateacher who must teach to 1 audience. It allows learners to choose the pace ofinstruction fast for strong learners, slow forthose having difficulty. It allows the repeating of information as manytimes as necessary for learners having difficulty 11. Elements needed for good multimedia design 12. ConsistencyUsers expect that different applications willhave a sameness to them which meansknowledge is transferable to a similarproduct. Ie Disk symbol means save onmost programs Also consistency is when buttons are inthe same place from page to page or formto form. 13. Feedback Feedback describes elements that givesthe user a response. Example: buttonsclicked make noises. A progress barshowing how long until a process iscompleted. 14. Forgiveness High forgiveness allows users to undomistakes or undo previous decisions in aprogram. All actions should be reversible. 15. 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 (hurtseyes) 16. Social and Ethical Issues Copyright Piracy Changing nature of work 17. Storyboards help us design and document Multimedia 18. The main theme The option topic is about how multimedia can be used tocommunicate 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 19. Vocabulary of Multimedia Enhance to raise to a higher degree; intensify;magnify: Video and Audio enhanced thestudents learning 20. Synergy Synergy - the cooperative action of two or more elements forgreater effect than either alone. Example: The effect of Multimedia is one of synergy. Videoand Text together create a more powerfullearning/entertainment/business impact than each shown bythemselves. 21. Engage to occupy the attention or efforts of (aperson or persons): The video, voicenarration and then interactive testengaged the student 22. Interact Interact: To act on each other Interactive multimedia means the user andprogram act upon the other. Both areactive processes. 23. Vector GraphicsVector graphics use mathematical Formulas to store graphic dataThis line might be stored as A3:F3Only 2 points need to be rememberedand stored on the HDD. When it is on your screen however it must be displayed as pixels 24. Vector Graphics These coordinates or vectors are knownas primitives. When stored on disk theyare referred to as primitives as they arenot formed yet. 25. Graphics & Multimedia 26. Vector graphics As co-ordinates only need to be remembered, lessspace is needed in storage. You can blow up pictures as large as required withoutdistortion or loss of info Because of this it is perfect for plan diagrams such asblueprints, 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 graphicsprogram. * Paint is bitmap 27. Frame Buffer The frame buffer or Video Ram is an area of very fast memory that containsthe bitmap image of the current screen display Still pictures and movies must be displayed Memory Chip 28. MonitorFrame buffermirrors exactlythe contentsof the frameFrame buffer or VRAMcontains the bitmap imagebufferwith the details of each pixel Each pixel and its location needs to be stored on your HDD 29. The Frame Buffer and Image sizeBIT DEPTHRelationships Number of Colors 12 1 2 22 2 4 32 38 42 4 16 82 8 25616 (high color) 2 1665536 24 (true color)2 2416777216 30. The Frame buffer and Image size Resolution is measured by the number ofpixels per inchEach Square is the same size but theone with the most dots has higherresolution HighLow 31. Jaggies orResolution & 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 32. 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-AliasingAnti-Aliasing 33. 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 34. 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 35. Dithering Examples 36. How to calculate image size800 pixels Bit plane is set At 24 bits600 pixels 37. 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 1024Bit plane set at 24 bits600 pixels1440 000 /1024 = 1406kbCalculate the number of megabytes by dividing by 1024 since there are 1024 kb in a megabyte1406 / 1024 = 1. 44mb (rounded up to the nearest mb) 38. How to calculate the time needed to download orupload the file USING A 56KB/S MODEM @ 200BITS PER SECONDFormula is Size of file / total amount transferred per second800 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 39. 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 40. Charged coupleddevice (CCD)converts light intodigital data orconverts digitaldata into lightVideoFirewirecardUSBAnalogue Digital moviecapturefile can now becard editedCapture digital data from digital video cameraIf it is an analogue camera, a video capture card is needed tosample the analogue data 41. Codec Firewire card USB Codec Analogue capture Digital movie file can now card be editedCoder-decoder." A device or software application that converts analoguevideo and audio signals into a digital format for transmission. Also convertsreceived digital signals back into analogue format. 42. Video Compression Example Mpeg or Divx Frames are analysed and section of theframes are analysed. If sections within frames are the samesuch as a car coming down the road.Repeated elements such as trees aretaken out. They are replaced upondecompression. 43. 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. 44. SamplingTo Sample: To take portions from the whole to make arepresentative of the whole 45. Illustration of SamplingAnalogue SoundwaveDigitally sampled Soundwave 46. MICROPHONEHow to sample a sound or digitally convert it fromanalogue to digitalADC 000100100101101010101000 COMPUTERMEMORY 000100100101101010101000 DACSPE 47. MICROPHONESampling ADC 01000 0001001001011010101 COMPUTERMEMORY DAC 01000 0001001001011010101SPEAKERReal World Analogue signals are converted to 0s and 1sNot all the sound information is recorded. Only important samples along the analogue wave.What is useful? Only what humans actually hear 48. Digital AudioThe type, size of the file and quality of digital audiodepends on 3 elements:1. Frequency (11 khz, 22 khz or 44 khz)2. Mono / Stereo3. Resolution: bit size of the samplings 49. 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 1