CS4624 Devices

• Digital media devices
  
  
  • Capture
    
    
    • Keyboards: ASCII, MIDI
      
    • Digitizers: Audio, video
      
    • Frame grabber
      
    • Scanner, OCR, eyetracking, infared remote control, joystick, mice, speech recognition, tablets, touchscreens, trackballs, whiteboard
      
    
    
  • Presentation
    
    
    • Framebuffer, display driver
      
    • Printer
      
    • MIDI synthesizer
      
    • Audio D-A converter
      
    • Aroma dispenser, headphone, speech synthesizer, whiteboard
      
    • Monitor:
      
      
      • higher resolution screens with at least 640x480 video
        
        
        • SVGA is 640x480, 256 colors, CLUT
          
        • 15 bit SVGA handles 32,768 colors
          
        • 24 bit handles 16,777,216 colors
        
        
      • fast graphics
        
        
        • 24 to/from 8 bit color conversion
          
        • dithering (e.g., 24 to 8)
          
        • e.g., Heckbert's median cut algorithm; N.B. If only have 4 bits, it is better to switch to gray scale
        
        
    
    
  • Processing
    
    
    • Audio/video codec
      
    • Audio/video effects device
      
    • Sound boards
      
      
      • sampling rates to 44.1 kHz for 16 bit samples
        
      • Sound Blaster is one of the original "standards" (in MPC).
        
      • MIDI is cheaper with an FM synthesizer, that generates sounds algorithmically.
        
      • Wavetable synthesizers cost more, but sound more realistic, and use stored waveforms from actual instruments.
        
      • DSPs are desirable because of their flexibility.
        
      • 48 kHz audio is slightly better, but hard to tell the difference
      
      
    • 3D graphics hardware
    
    
  • Storage
    
    
    • Optical: erasable optical: e.g., 3.5 inch, 128 Mb MO, $40 each
      
    • Magnetic tape: helical scan
      
    • Magnetic disk
      
    • Jukebox: caching, staging for tertiary store; have max. possible no. of drives
  
  
• Analog media devices
  
  
  • Sources
    
    
    • Microphone
      
    • Video camera, videodisc, video tape player
      
    • Audio tape player
      
    • Photographic camera
    
    
  • Sinks
    
    
    • Speakers, audio tape recorders
      
    • Video displays, tape reporters
    
    
  • Filters
    
    
    • Audio/video effects device
      
    • Audio/video mixer (switcher)
      
    • Video scan converter, overlay device
      
    • Routing switch, edit controller
    
    
  • Video synchronization: sync generator, timebase corrector

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  [ Home | Lecture Notes | Lecture 7 ]
  Copyright 1996 Edward A. Fox