Multimedia Assets

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• Multimedia Assets

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Multimedia Assets

• Text
• Sound
• Graphics
• Animation
• Video

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Text

• Text always appears in Multimedia applications.
• It should not take over.
• Users of multimedia systems do not wish to be
  reading the screen
• They want to be interacting with the system.

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• Text presented on-screen is quite different from
  text presented on the printed page.
• Need to consider
• Body Text
• Headings
• Titles

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Properties of Text

• Font
• Strictly speaking, refers to a single size and
  style of a typeface.
• Typeface
• Typeface refers to the style and shape or design
  of the characters.

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Examples of typeface

• Arial Times New Roman
• Tennessee SF Century Schoolbook
• Beatnik SF Accent SF
• Bookman Old Style

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Properties of Text

• Font Size
• Fonts come in a range of sizes, which are
  measured in units called points.
• A point is approximately 1/72".
• Thus a 12-point font is 12/72" or 1/6" high, and
  a 36-point font is 1/2" high.
• The size of a font is actually the distance
  between the baselines of adjacent rows of text,
  measured in points.

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Font styles

• Number of different styles, but not all of them
  are suitable for screen display use.
• Bold, italic and bold italic suitable for
  headings and titles
• The style small capital letters use should be
  strictly limited
• RESEARCH HAS SHOWN THAT TEXT IN ALL CAPITAL
  LETTERS is more difficult to read than text with
  upper- and lower-case letters.
• Outline and shadow should not be used

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Serifs

• Serifs are little finishing strokes on the ends
  of the lines that form a character.
• A font that has serifs can be contrasted with
  another font that is sans-serif (i.e., it has no
  serifs)
• Serif
• Sans-serif

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• A study has shown that readers preferred a
  sans-serif font for text on a computer screen
• but a good deal more research is needed on this
  point.

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• Fonts represented with vector graphics are called
  scalable fonts , outline fonts , or vector fonts.
  
• The best-known example of a vector font system is
  PostScript.
• Bit-mapped fonts, also called raster fonts, must
  be designed for a specific device and a specific
  size and resolution.

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• Proportional Fonts
• A font in which different characters have
  different pitches (widths)
• Non-proportional Fonts
• A font in which all characters have same width

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Anti-aliasing

• One of the most important techniques in making
  text easy to read and pleasing to the eye
  on-screen is anti-aliasing.
• Anti-aliasing is a way of getting rid of jagged
  edges. It is a smoothing process.
• Works best on larger font sizes

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• The characteristics of a good font for body text
  may be different to those for headings or titles

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• For body text on-screen, you would do well to
  choose a font with these characteristics
• minimum 12- or 14-point size
• (if the typeface has relatively small characters
  compared to other typefaces of that size (e.g.,
  Times), choose 14
• if the characters are relatively large (e.g.,
  Bookman), you can choose 12)
  

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• plain (roman) style, rather than bold, italic,
  outline, shadow, or other style
• sans-serif or with serifs that are not too fine
  to render well on-screen
• bitmap font rather than outline font
• proportional font (unless it is necessary to
  choose a non-proportional font for some reason)
• not anti-aliased
• system-resident font (preferred)

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• For headings and titles on-screen, you should
  generally choose a font with these
  characteristics
• 18-36 point size (assuming 12- or 14-point body
  text)
• plain (roman) or bold style is acceptable
  italics may be used if the font size is large
  enough to render well on-screen

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• either sans-serif or serif typeface is acceptable
  
• it often works well to have the opposite of body
  text - i.e., if body text is sans-serif, make
  titles/headings serif, and vice versa
• due to the size of titles/headings, outline fonts
  may render well enough on-screen to be useable

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• proportional font
• anti-aliased titles/headings generally look more
  pleasing
• can use a DTP package to adjust properties such
  as spacing, kerning, leading
• system-resident typeface (preferred )

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Sound

• For producing, editing and digitising sound need
  appropriate software and (in PCs cards such as
  Soundblaster).
• Two ways of processing Sounds - MIDI Digital
  Audio

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• MIDI (Musical Instrument Digital Interface) is a
  communications standard developed in the early
  1980s for electronic musical instruments and
  computers
• It allows music and sound synthesisers from
  different manufacturers to communicate with each
  other

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• Sends messages along cables connected to the
  devices.
• MIDI provides a protocol for passing detailed
  descriptions of a musical score, such as notes,
  sequences of notes and what instrument will play
  these notes

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• MIDI is not digitised sound
• a shorthand representation of music stored in
  numeric form.
• A MIDI file is a list of time-stamped commands
  that are recordings of musical actions.

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• Digital Audio is digitised sound which can come
  from a microphone, a synthesiser, existing tape
  recordings, live radio and television broadcasts
  and CDs.
• You can digitise sound from any source.
• Digitised sound is sampled sound.

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• Every nth fraction of a second is taken and
  stored as digital information in bits and bytes.
• How often the samples are taken is the sampling
  rate, and the amount of information stored about
  each sample is the sample size.

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Midi versus digital Audio

• MIDI data is device dependent, digital audio is
  not.
• MIDI files are much more compact than Digital
  Audio and the size of a MIDI file is completely
  independent of playback quality.
• MIDI can, on occasions, sound better than digital
  audio if MIDI sound source is of high quality.

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• As MIDI data isnt sound, you cannot be certain
  that playback will be accurate. It will only be
  accurate if the MIDI playback device is identical
  to the device used for production.
• MIDI cannot easily be used to play back the
  spoken word.

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• A wider selection of software and system support
  is available for Macintosh and PC.
• The preparation and programming required for
  creating digital audio do not require a knowledge
  of music theory.

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Audio file Formats

• Digitised sounds on Macintosh are stored as .AIF
  or .SND
• In Windows digitised sounds are stored as .WAV
  files.
• Microsoft PCM and Macintosh .AIF files can be
  understood and translated to and from .WAV by
  WaveEdit and Convert programs.

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• Both Macintosh and Windows can make use of MIDI
  files.
• Sound boards on PC have MIDI interfaces.
• MIDI adapter is required for Macintosh.
• On both platforms, MIDI sounds are typically
  stored as .MID files.