1. Computing Intermediate 2 Multimedia Technology

2. The Development Process and Multimedia Applications
The Software Development Process and Multimedia Applications
Analysis: The main purpose of this stage is to be absolutely clear about what the multimedia project is supposed to do.

3. The Development Process and Multimedia Applications
Design: Producing a detailed plan which defines what the different parts of the project are and how they are linked together.

4. The Development Process and Multimedia Applications
The Software Development Process and Multimedia Applications
Implementation: This is the point at which the multimedia authoring, or web-page authoring, package is used to turn the design into a working project.

5. The Development Process and Multimedia Applications
The Software Development Process and
Multimedia Applications
Testing: A series of practical tests are carried out to check that the multimedia project functions properly.
Documentation: User Guide and Technical Guide.

6. The Development Process and Multimedia Applications
The Software Development Process and
Multimedia Applications
Evaluation: Checks that the finished application meets the user’s requirements. Includes an assessment of the HCI design.
Maintenance: Fixing bugs and adapting the design to suit client needs and the demands of new technology.

7. Methodologies used in creation of multimedia applications
Text editor: Creating simple web pages using HTML.
WYSIWIG editors: Previewing applications under development to check that what you see is what you get.
Multimedia authoring packages, e.g. Mediator Pro.
Presentation software, e.g. PowerPoint.

8. Methodologies used to view multimedia applications
Displaying multimedia applications in a browser.
Displaying multimedia applications using a file player or viewer.

9. Methodologies used to view multimedia applications
Multimedia application as an executable file

10. Bit-mapped Graphic Data
Capturing still images using a digital camera
Using a CCD to capture light coming in through a lens
CCD charged coupled device: uses sensors to capture light
Capturing images using a scanner: also uses CCD

11. Bit-mapped Graphic Data
Storing graphics as a bit map: each pixel in the image is represented by a binary number.
Uncompressed bit-map format: a file which holds a binary number for each pixel in an image.
Large file size: main limitation of bit-map format.
Need for compression: to relieve demands on storage and transmission times.

12. Bit-mapped Graphic Data
Compression using GIF format
Lossless compression: GIF format compresses graphic data without losing any information about the image. It compresses by encoding repeated patterns of data.
Limited number of colours: limited to 28, 256 colours.
Transparency: colours set as transparent let the background colours and patterns show through.
Used for storing cartoons, and line drawings.

13. Bit-mapped Graphic Data
JPEG
Uses lossy compression: parts of the graphic are cut out, e.g. shades of colour. At low rates of compression this is not noticeable.

14. Bit-mapped Graphic Data
JPEG
JPEG format suitable for storing photographs
and paintings.

15. Bit-mapped Graphic Data
Trading quality for file size
Resolution: increasing resolution increases the number of pixels, can improve the quality of a graphic but increases the file size.
Colour depth: increasing colour depth increases the number of colours or shades of grey, can improve the quality of a graphic but increases the file size.
Lossy compression: reduces file size and, providing the rate of compression is not too high, does not affect the quality of the graphic.

16. Bit-mapped Graphic Data
Simple bit-map editing and creation software
Painting programs
Fill tool: a feature for pouring colour into a graphic.
Paintbrush tool: for more precise application of colour.

17. Bit-mapped Graphic Data
Main features of image editing programs
Decrease resolution
Alter colour depth
Crop
Alter brightness and contrast
Insert graphic
Re-size.

18. Bit-mapped Graphic Data
Hardware for displaying 2D graphics
CRT monitor: bulky, heavy, run on mains power, cost less than equivalent TFT screens.
LCD and TFT screens: flat, light, need less power, more expensive than CRT.

19. Bit-mapped Graphic Data
Hardware for displaying graphic data
Need for graphics cards to store and process graphic data, relieving the main processor of the task.

20. Hardware for capturing sound
Digitised Sound Data
Hardware for capturing sound
Microphone
Sound cards: to sample, store and process audio data.

21. Uncompressed sound data
Digitised Sound Data
Uncompressed sound data
RAW: Uncompressed samples of sound waves
RIFF: Resource Interchange File Format
WAV: Microsoft's format for sound files, part of RIFF

22. Digitised Sound Data
Lossy compression: reduces file sizes by cutting out some of the data.
MP3: uses lossy compression without noticeable loss of sound quality.

23. Balancing file size and sound quality
Digitised Sound Data
Balancing file size and sound quality
Sampling depth: increased sound depth = greater range of values = better sound quality and greater file size.
Sampling frequency: The higher the sampling frequency, the better the sound quality, the greater the file size.
Sound time: affects file size but not quality.

24. Simple sound editing software
Digitised Sound Data
Simple sound editing software
Reducing sample frequency, e.g. from 44.1 KHz to KHz, reduces file size and audio quality.
Reducing sample depth, e.g. from 16 bits to 8 bits per sample, reduces file size and audio quality.

25. Digitised Sound Data Editing sound file features: Volume Effects Echo
Reverse

26. Digitised Sound Data Sound cards and playback:
Sound cards needed to change the digital audio data into analogue signals to control output from speakers.

27. Hardware for capturing images
Video Data
Hardware for capturing images
Digital video camera
Web cam

28. Video Data Storing video data Uncompressed format
Uncompressed video data = Large file sizes
1 second of uncompressed wide-screen video can take up 53 Megabytes of storage
AVI: Audio Visual Interleave, an uncompressed format.

29. Compressing video data
MPEG-2
Lossy compression: cuts out unnecessary parts of a video clip

30. Compressing video data
Using MP3 compression:
Reduces file sizes
With no noticeable loss of video quality.

31. Video quality and file size
Video Data
Video quality and file size
Colour depth: increasing colour depth improves quality and file sizes.
Resolution: increasing resolution improves quality and increases file sizes.
Frame rate: measured in frames per second, fps. 30fps is the rate for a video clip. Increasing frame rate increases file size. Lower frame rates reduce file size but make video clip ‘jerky’.

32. Video quality and file size
Video Data
Video quality and file size
Video time: increasing or reducing the time of a video is the obvious way to affect the file size. Quality of the display of the clip is not affected.
Lossy compression: Using MP3 compression reduces file sizes without affecting quality.

33. Video Data
Video editing software features and applications used with single video clips
Cropping: cutting unwanted data from the beginning and end of a clip.
Add effects, titles, sound tracks.
The need for graphics cards to process and output video data.

34. Basic features of vector graphics
Vector Graphics Data
Basic features of vector graphics
They are scalable: resolution independent.
In a vector graphic individual objects can be edited.
Graphics can be assembled by placing objects in layers.

35. Vector Graphics Data Common attributes of vector graphic objects
Position
Shape
Size

36. Vector Graphics Data Common attributes of vector graphic objects
Rotation
Line
Layer
Fill

37. Vector Graphics Data Attributes of a 3D image Shape Position Size
Rotation
Texture

38. Standard formats for vector graphics
Vector Graphics Data
Standard formats for vector graphics
Scalable Vector Graphics (SVG) format
Scalable: resolution independent
Vector: represents objects by defining a series of attributes

39. Standard formats for vector graphics
Vector Graphics Data
Standard formats for vector graphics
Virtual Reality Markup Language
A standard language used to model and animate geometric shapes
Used to define 3D environments for the WWW.

40. Synthesised Sound Data
Musical Instrument Digital Interface: MIDI
Common attributes of notes stored as MIDI data:
Instrument: defines which instrument is playing
Pitch: defines the height of the note
Volume: determines the amplitude
Duration: determines the length of the note.

41. Synthesised Sound Data
Common attributes of notes stored as MIDI data
Duration: determines the length of the note.
Tempo: the speed at which a piece of music is played.

42. Implications: Multimedia Technologies
Converging contemporary technologies
Smartphone: merging technologies of a mobile phone and a laptop.
Pocket PC: merging technologies of a laptop, mobile phone and desktop
operating system and application
software.

43. Implications of Multimedia Technologies
Contemporary technologies
Digital television: an interactive multimedia device which, because of the digital nature of its signals, is easily integrated into your digital computer and home networks.

44. Implications of Multimedia Technologies
Contemporary technologies
Virtual reality
The ultimate multimedia experience where the user is immersed in the world of the computer and can journey through, and interact with, a computer generated 3-dimensional multimedia world.

45. Implications of Multimedia Technologies
Immersive VR
Output :Using speakers, stereo screens, headsets
Input: sensors in gloves, headsets and suits