Computing Intermediate 2 Multimedia Technology

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ComputingIntermediate 2Multimedia Technology
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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.

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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.

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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.

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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.

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The Development Process and Multimedia
Applications

• The Software Development Process and
• Multimedia Applications
• Evaluation Checks that the finished application
  meets the users 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.

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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.

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Methodologies used to view multimedia applications

• Displaying multimedia applications in a browser.
• Displaying multimedia applications using a file
  player or viewer.

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

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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.

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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.

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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.

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Bit-mapped Graphic Data

• JPEG
• JPEG format suitable for storing photographs
• and paintings.

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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.

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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.

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Bit-mapped Graphic Data

• Main features of image editing programs
• Decrease resolution
• Alter colour depth
• Crop
• Alter brightness and contrast
• Insert graphic
• Re-size.

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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.

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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.

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Digitised Sound Data

• Hardware for capturing sound
• Microphone
• Sound cards to sample, store and process audio
  data.

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Digitised Sound Data

• Uncompressed sound data
• RAW Uncompressed samples of sound waves
• 
  
  0101010101010101 1111111101010101
• 
  
  0011001100101011 1100101000110001
• RIFF Resource Interchange File Format
• WAV Microsoft's format for sound files, part of
  RIFF

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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.

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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.

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Digitised Sound Data

• Simple sound editing software
• Reducing sample frequency, e.g. from 44.1 KHz to
  22.05 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.

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Digitised Sound Data

• Editing sound file features
• Volume
• Effects
• Echo
• Reverse

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Digitised Sound Data

• Sound cards and playback
• Sound cards needed to change the digital audio
  data into analogue signals to control output from
  speakers.

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Video Data

• Hardware for capturing images
• Digital video camera
• Web cam

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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.

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Video Data

• Compressing video data
• MPEG-2
• Lossy compression cuts out unnecessary parts of
  a video clip

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Video Data

• Compressing video data

• Using MP3 compression
• Reduces file sizes
• With no noticeable loss of video quality.

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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.

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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.

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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.

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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.

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Vector Graphics Data

• Common attributes of vector graphic objects
• Position
• Shape
• Size

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Vector Graphics Data

• Common attributes of vector graphic objects
• Rotation
• Line
• Layer
• Fill

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Vector Graphics Data

• Attributes of a 3D image
• Shape
• Position
• Size
• Rotation
• Texture

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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

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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.

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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.

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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.

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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.

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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.

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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.

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Implications of Multimedia Technologies

• Immersive VR
• Output Using speakers, stereo screens, headsets
• Input sensors in gloves, headsets and suits