The document discusses multimedia and its key characteristics. Multimedia combines various media types like text, audio, video and images. It allows for interactivity through hyperlinks and user input. Characteristics include engaging multiple senses, being nonlinear and self-paced. The document also covers topics like digitization of media, file types for images, audio and video, as well as animation techniques.

1. M u l t i m e d i a

2. What is Multimedia? the combination of a variety of different media (data types): text and numbers audio video images animation to add interactivity, hypertext and other forms of hypermedia.

3. What is Interactivity? refers to the user being able to make an immediate response to the product and modify processes there is a dialogue between the user and the input device this communication may result in linear or non-linear path through the product dynamic interactivity results when the product changes, depending on the action taken by either the author and/or the user some products use indexing to remember position in the product

4. Characteristics of Multimedia it can increase the impact of the message or impact on the user multimedia systems involve interactivity information on demand, as required, controlled by the user, can be self-paced, cross referenced via hyperlinks content can be selected by user learning style (learn by doing) involves multi-senses

5. Characteristics….. can involve more than one input device can be structured to build on previous learning can have feedback on performance can be repeated (over and over) hyperlinks / hypertext can be utilised (navigation buttons) involves the user in the presentation allows input, provides output it is generally dynamic, not static

6. Text Strings of printable characters separated by white space characters (letters, numbers, symbols) main method of conveying information through language text size / style can be used to emphasis content used for titles, headlines, menus, content software can ‘speak’ text

7. Hypertext /Hypermedia Text presented in such a way that supports direct, intuitive navigation between elements of the text of other information Hotspots can also be used : usually termed hypermedia as they are often linked to images, video or audio media text / hotspots are linked with other cards / pages/ documents

8. Digitising data Presentation of the product CD-ROM, DVD, Video Analog v Digital size and type of files quality of product timing sequence planning - storyboards

9. Lossy vs Lossless Lossy compression removes a number of data bytes from a file. The resulting file is smaller in size but the quality is reduced However, audio and video files can be compressed with high compression ratios and without any change noticable to the human ear or eye Lossless compression allows the original file to be recovered in full. It works by replacing repeated data with something that takes up less room

10. Images - Bitmapped vs Objects BITMAPPED a section of memory consisting of a series of zeroes and ones corresponding to pixels on the screen for colour, a number of bits are used to represent the colour value of each pixel a correspondence between memory locations and elements of the output pattern on various output devices the frame buffer is a section of memory used to store that data for the current image being displayed

11. Bitmapped images usually require anti-aliasing to remove ‘jaggies’ Jaggies - the staircase roughness of oblique lines and polygon edges in computer images caused by the underlying squareness of the pixel Anti-aliasing - the process of removing faults such as jaggies in computer images caused by the physical size and shape of the pixel

12. OBJECTS / VECTOR stored as mathematical entities, eg. Coordinates, width, colour, intensity etc the vectors are defined only by their starting and finishing points vector graphics are also known as objects typically these images are smaller in file size and easily scaled than bitmapped images

13. Dithering Dithering - the representation of a colour not available in the existing palette by the use of a pattern of varying colours where the eye performs the averaging to produce the required colour a Mask can be used to protect an image and not allow editing to alter the size of the file, combinations of colour palette and dithering can be used

14. Common Image File Types

15. Audio Sound is analog in nature, and to be used in multimedia, needs to be digitised creates mood, interest, includes speech audio files are usually large files unless they have been compressed Audio can be in 2 basic formats: a digitised file of the actual sound eg. WAV file or in compressed format MP3 MIDI (Musical Instrument Digital Interface) where details of the characteristics of each note is filed

16. Digitised Audio the quality of the sound depends on the sampling rate, sampling size, time and number of channels sampling rates are from 10 to 44 kHz with CD-ROM having a sampling rate of 33kHz slow rates result in loss of quality and distortion sampling size refers to how many bits are used to record (bit resolution)

17. 16 bits gives 65536 possible level of sound 8 bits gives 256 (and smaller files) sound can also be in mono (1 track) or stereo (2 track) CD-ROMs are popular storage devices as they allow direct (non-linear) access. 44kHz at 16 bit for 60 sec = 10.5Mb 22kHz at 8 bit for 60 sec = 2Mb

18. Audio Compression Minimal Hearing Threshold the human ear can only receive sound between 20Hz and 20kHz any sound not within this range is discarded as the information is of no use Masking Effect when you hear sounds, the louder, more prominent sounds mask the quieter sounds in terms of compressing the sound, we can remove the quieter sounds that we cannot distinguish from the louder sounds Managing Sound Redundancy where a sound occurs simultaneously on both channels, it is recorded once for both channels to use, rather than recorded separately

19. Digitised Audio File Types

20. MIDI The details of the actual notes played, on, off, velocity, pitch bend, after touch, program change, length, tone, etc. are all kept in the file MIDI files when played require a MIDI keyboard or device to interpret the notes and then produce the sound MIDI files are used by musicians to multi-track, mix and write scores Hardware required includes controller (keyboard), synthesiser, MIDI port and a computer running MIDI software hence file size is very small

21. Video Video is real image recording usually requires data compression (CODEC) to allow a smaller file, and decompression to play requires high VRAM and storage space typically, 20 minutes of video is 8GB. Since 1 frame at 24 bit = 1Mb file types include MPEG (Lossy) and Quicktime, AVI (Lossless)

22. Lossy CODEC’s find data that can be removed and delete this without much quality loss thus making the video smaller Lossless CODEC’s look for patterns of pixels replacing them with a code between each frame for example: the background may be stationary and the person moves, so the background is saved using a code which represents it, and only changes when a new background appears Digital video cameras simplify the process, as “S” video or firewire ports allow transfer of digital data between the camera and computer to reduce file size the frame rate, screen area, palette, file type and CODEC can be changed Video cards usually allow frames to be captured (frame grab) can be edited via software (including iMovie, Adobe Premiere, Quicktime, Quicktime VR)

23. Video File Types

24. Animation A series of still images that have been manipulated to give the appearance of movement or life like motion the frame rate determines the persistence of vision and smoothness of image to the user 30 frames/sec refresh rate (flicker free) 25 f/s PAL 24 f/s Movies 12 f/s Cartoons 8 f/s minimum when the animation speed matches the refresh rate of the screen, the image is flicker free

25. Cell-Based Animation Creation of individual images in cells (frames) which when played produces motion this type of animation is the traditional method

26. Path-Based Animation The start and end point and path for the object to follow are defined by vectors the background is fixed saves memory and processing time especially if the image is an object

27. Tweening The process of taking two images of an animation and producing intermediate images so that the animation appears smooth

28. Effects - Morphing The process of transforming an image into a new image that is different to the start image especially in terms of the shape of objects

29. Effects - Warping The distortion of an image by mathematical processes

30. Effects - Dynamic Time of day / time of year animations this shows changes in lighting (especially sun impact) over the day or changes over the year at a fixed time of day Walk-through animations this shows a scene from a succession of different view points creating the illusion of motion through the scene Feature animation this modifies scene attributes dynamically it can also be used to let objects in a scene appear or disappear by manipulating their transparency this is achieved by rendering several variations of a scene and interpolating the resulting images

31. Effects - Dynamic... Geometry animation this is the most complex requires changing the geometric elements of a scene dynamically this technique has been used in pictures like “Terminator II”, “Jurassic Park”, “Toy Story” and many others this is what most people refer to when using the term animation

32. Compression strategies can take advantage of 4 kinds of redundancy Coding Redundancy relies on the fact that not all data will occur with the same probability compression algorithms also use the fact that it is likely that the same data will often repeat Spatial Redundancy occurs because pixels which are near each other are likely to be similar to each other Temporal Redundancy occurs because pixels in consecutive frames of a video are likely to be similar MPEG takes advantage of this Psychovisual Redundancy occurs because the human visual system is better at seeing changes in luminance (brightness) than in seeing the changes in chrominance (colour)

33. Information Processes - Collecting Collecting involves data being obtained from a variety of sources text and number are gathered digitally video, audio, images are gathered via analog means and then interpreted into digital form

34. Information Processes - Organising The way information is organised in multimedia product is through storyboarding and screen design when organising there are some steps which need to be followed: determine the intended audience create a storyboard plan your navigational tools create an aesthetically appealing production

35. Information Processes - Analysing Through the analysis stage, data is turned into useful information it involves the testing and retesting of the multimedia presentation different design methods can also be applied such as top-down design

36. Information Processes - Storing / Retrieving In this information process some things need to be determined such as: initially, data may be stored and collected in analog from such as videos, audio tape, etc elements may also be stored digitally such as hard drives, CD-ROMs, DVD Flash media, tape drives etc. what type of compression techniques will be used how will it be distributed, CD-ROM, DVD due to high level of production rate Will it require Internet distribution?

37. Information Processes - Processing Processing is the manipulation of data the individual components that will be included into a multimedia presentation need to be processed before being organised by the multimedia software In this information process, all the elements need to be processed, ie. Animations created, text formatted, sound and video being edited and compressed via CODEC’s

38. Information Processes - Transmitting and Receiving Multimedia delivery is an important decision it must be decided whether it will be delivered via CD-ROM, DVD or the Internet depending on the decision, access speed, bandwidth and other infrastructure will need to be considered

39. Information Processes - Displaying Displaying needs to be considered at both the hardware level and the software level the method of projection needs to be considered will the production be projected, use head up displays, touch screens etc? will the production fit on the display, ie. Navigation, features etc in terms of software, what will the ‘run-time engine’ be? If delivered on the internet, what is the lowest common denominator for “plug-ins”?

40. Hardware demands by multimedia The hardware of a multimedia system places limits On the quality and size of the multimedia product that Can be produced or displayed.

41. Hardware demands by multimedia

42. Hardware demands by multimedia

43. Hardware demands by multimedia . Calculate the size of the following graphics (answer in Kb to the nearest whole number): 1. A black and white graphic with a resolution of 640 by 480 and 2 tones 2. A colour graphic with a resolution of 1024 by 768 and 64 colours 3. A colour graphic with a resolution of 1600 by 1200 and 256 colours 4. An 8 bit colour graphic with a resolution of 1280 by 1024 5. A 32 bit colour graphic with a resolution of 1152 by 864

44. Hardware demands by multimedia

45. Hardware demands by multimedia

46. Hardware demands by multimedia Calculate the size of the following audio files (answer in Mb, correct to 2 decimal places): 1. Sampling rate of 22.05 kHz with a 8 bit sound for 2 minutes in stereo 2. Sampling rate of 44.1 kHz with a 16 bit sound for 3 minutes in stereo 3. Sampling rate of 22.05 kHz with a 16 bit sound for 1 minute in mono 4. Sampling rate of 11 kHz with a 8 bit sound for 4 minutes in mono 5. Sampling rate of 44.1 kHz with a 16 bit sound for 10 minutes in stereo

47. Hardware demands by multimedia

48. Hardware demands by multimedia

49. Hardware demands by multimedia

50. Hardware demands by multimedia

51. IT Jobs check out www.course.com/careers/dayinthelife / www.course.com /careers/glossary/ Multimedia Presentation http:// shellmedia.cjb.net

52. IT Jobs check out www.course.com/careers/dayinthelife / www.course.com /careers/glossary/ Multimedia Presentation http:// shellmedia.cjb.net