CPT 299: Web Page Design

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CPT 299 Web Page Design

• Multimedia

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Multimedia

• The ability to transfer multimedia elements in
  web pages is a large part of the Webs popularity
• is the integration of multiple media -including
  text, graphics, sound, and video into a single
  presentation
• when using multimedia in web pages, bandwidth is
  a major consideration

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Bandwidth

• A measure of the amount of data that can be
  transferred over a communications circuit each
  second
• Low bandwidth connections include phone lines
• Sound and video files typically require a lot of
  bandwidth because of their size
• keep low bandwidth users in mind when choosing
  multimedia elements

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Using Multimedia

• Two ways to include multimedia into web pages
• external media - uses a hyperlink to access the
  sound or video file
• users can choose if they want to view the file
• inline media - clips are embedded directly into
  the web page
• users must wait for clip to be downloaded
• gives web designer more flexibility - text can be
  wrapped around clip, etc.

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Working with sound files

• Two components of a sound wave
• amplitude - the height of the sound wave relates
  to loudness
• frequency - speed at which the sound wave moves
  relates to pitch
• To convert sound waves to a form that can be
  saved in file, the computer must sample the sound

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Samples

• The measure of a sound wave at discrete moments
  in time
• sample rate - the number of samples taken per
  second
• measured in Kilohertz(KHz)
• most commonly used sampling rates are 11 KHz, 22
  KHz, and 44 KHz
• A higher sample rate more samples per second
  larger the file sizes

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Sample rates
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Sample Resolution

• The precision involved in measuring a sound
  within each sample
• can be either 8-bit or 16-bit
• 16-bit resolution represents the sound wave in
  greater detail than 8-bit resolution
• The higher the resolution, the larger the file
  size

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Sample Resolution
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Sound file formats

• AU - compatible with most Operating Systems
• AIFF - mostly used on Macs
• SND - not used much
• WAVE - compatible with most Operating Systems
• RealAudio - best for low bandwidth connections
  because file is downloaded and played at the same
  time
• MIDI - not a sampled sound, but computer-generated

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Where to get sound files

• You can create your own if you are using a
  computer with a sound card and some special
  software
• there are also many on the internet that you can
  use, go to Yahoos sound archives list
• Cool Edit sound editor- http//www.syntrillium.com

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Linking to a sound file

• Same as linking to other web pages
• lta hrefmysound.wavgtClick to hear me singlt/agt
• File will be downloaded to the users computer and
  then played

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Embedding a sound file

• Plug-ins are applications that allow the browser
  to read embedded files
• ltembed srcurl widthvalue heightvalue gt
• URL - the location and name of the file
• WIDTH - width in pixels of the control console
• HEIGHT - height in pixels of the control console

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Additional properties

• ltembed srcmysound.wav autostarttrue
  loopfalse alignright hiddentruegt
• autostarttrue tells the browser to the playing
  the file as soon as the page is loaded
• loopfalse keeps the sound from playing
  repeatedly
• ALIGN allows text to be wrapped around the
  console
• hiddentrue hides the control console

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Background sounds

• ltbgsound srcurl loopvaluegt
• loop is the number of times the sound will play
• only works with Internet Explorer