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Definition of Term

  • The proportional relationship between a screen display's width and its height.



  • Typical aspect ratios are:
    • 4:3 FULL SCREEN (4 units wide x 3 units high - 1.33x wider than high)
      • SD standard definition TV
      • although high definition screens can also be built in 4:3 like the iPad

    • 16:9 WIDE SCREEN (16 units wide x 9 units high - 1.78x wider than high)
      • HD high definition
      • Theater movie screens (some variation)
      • Most modern computer monitors are 16:9


    The different ratios cause the “black bars” or "letterboxing" that everyone grumbles about.

    • Playing a 4:3 image onto a 16:9 screen will cause vertical black bars on the right and left,
    • Playing a 16:9 image on a 4:3 screen will cause horizontal black bars on the top and bottom.
    • To make things more difficult, DVDs don’t have a standard widescreen aspect ratio. Therefore, you can get a DVD with an aspect ratio of 1.78, 1.85, 2.00, 2.35, 2.4, 2.5, or more . Anamorphic Widescreen aspect ratio of 2.35:1 is what most films are filmed in, and is a popular ratio for DVDs and Blu-ray.
    • Most high definition TVs allow you to zoom in or stretch an image to get rid of the black bars.