• What is the difference between Standard Definition (SD) and High Definition (HD)?

  • These pictures illustrate the basic aspect ratio difference between SD and HD:

    SD screen
    4:3 aspect ratio (almost square) or 16:9 letterboxed (cropped with black bars). The format of older television sets.

    Sample of SD screen

    HD (wider) screen
    16:9 aspect ratio. The format of modern day rectangular screens.

    Sample of HD screen