Multimedia Elements II

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Multimedia Elements II

• Graphics, Digital Video

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Multimedia Elements

• Multimedia elements include

Digital Video
Digital Audio
Text
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Multimedia
Graphics
Animation
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Multimedia ElementsGraphics

• Graphics is a digital representation of non-text
  information such as a drawing, chart, or
  photograph.
• It is also called a digital picture or image, and
  contains no movement or animation
• 3 fundamental characteristics of color
• Hue (??)
• Related to the wavelength of light
• Lightness (??)
• Related to the amplitude of light
• Saturation (??)
• Related to the purity of light

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Multimedia ElementsGraphics

• Pixel
• A pixel is the smallest unit of programmable
  color on a computer display or in a computer
  image
• Every computer graphic is made up of a grid of
  pixels
• There are two types of graphics
• Bitmap graphics
• Vector graphics

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Multimedia ElementsGraphics

• Bitmap Graphics
• Bitmap is a representation of a graphics image
• Consists of rows and columns of dots
• The value of each dot (whether it is filled in or
  not) is stored in one or more bits of data
• Simple monochrome images use one bit to
  represent each dot

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Multimedia ElementsGraphics

• Bitmap Graphics
• The more bits used to represent a dot, the more
  colors and shades of gray that can be
  represented

1-bit image, 2 color black or white

8-bit image, 256 colors (28256)
24-bit image, 16777216 colors (true color)

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Multimedia ElementsGraphics

• Vector Graphics
• Vector graphics are based on mathematical
  formulas that represent curves and lines
• Very smooth looking and can easily be resized
  without loss of image quality
• Bitmap Vector
• 00000000000000 (3, 2) ? (10, 2)
• 00111111111100
• 00000000000000
• 00000000000000

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Multimedia ElementsGraphics

• Vector Graphics
• An example of vector graphic is the clipart in MS
  PowerPoint
• When you enlarge a clipart image, it will not
  distort

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Multimedia ElementsGraphics

• Resolution
• Determines how sharply the image is represented
• Expressed in dot per inch (dpi), or simply by the
  number of rows and columns, such as 640 by 480
• Bitmap graphics suffer distortion in image
  quality when being scaled up, this does not
  happen in case of vector graphics

Vector graphic
Bitmap graphic
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Multimedia ElementsGraphics

• Formats
• A format is a standard specifying how the data is
  arranged
• For bitmap graphics
• BMP
• GIF
• JPEG
• For vector graphics
• AI
• FH
• WMF

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Multimedia ElementsGraphics

• Formats
• BMP (.bmp)
• Microsoft's native graphic file format
• GIF (Graphic Image Format) (.gif)
• Only supports 256 colors It serves as compressed
  web graphics. GIF works best when the number of
  colors within an image is small
• JPEG (Joint Photographic Experts Group) (.jpg)
• Supports millions and allows for graphic
  compression. Most people use JPEG for Web
  graphics that contain a multitude of colors and
  gradations - like photographic images
• AI (Adobe Illustrator) (.ai)
• For graphics produced by Adobe Illustrator
• FH (FreeHand) (.fh)
• For graphics produced by FreeHand
• WMF (Windows Metafile Format) (.wmf)
• For exchanging graphics between Microsoft
  applications such as clipart in Microsoft Office

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Multimedia ElementsGraphics

• GIF versus JPEG
• When the number of color of an image is large,
  JPEG performs better

JPEG format, 6k bytes
GIF format, 13.5k bytes
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Multimedia ElementsGraphics

• GIF versus JPEG
• When the number of color of an image is small,
  GIF performs better

JPEG, 5.4 bytes
GIF, 1.5k bytes
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Multimedia ElementsComputer-based Animation

• Animated GIFs
• Animated GIFs are a special kind of GIF file
  known as GIF89a
• An animated GIF file stores multiple images as
  separate blocks within a single GIF file
• When being viewed on the Web, the multiple images
  are streamed (played back one at a time)
• Streaming the viewer does not have to wait for
  the entire GIF to be downloaded before it begins
  running on a Web page