Updated 18/11/2012Home » Video Glossary » Progresive Scan

Progresive Scan

Progressive scanning (or non-interlaced scanning) is a way of displaying, storing, or transmitting moving images in which all the lines of each frame are drawn in sequence. This is in contrast to interlaced video used in traditional analog television systems where only the odd lines, then the even lines of each frame (each image called a video field) are drawn alternately.

Progressive scan is used for scanning and storing film-based material on DVDs, for example, as 480p24 or 576p25 formats. Progressive scan is also used for most CRT computer monitors, all LCD computer monitors, and most HDTVs as the display resolutions are progressive by nature. Other CRT-type displays, such as SDTVs, typically display interlaced video only.

Advantages of progressive scan versus interlaced scan

  • Absence of visual artifacts associated with interlaced video of the same line rate, such as interline twitter.
  • No necessity in intentional blurring (sometimes referred to as anti-aliasing) of video to reduce interline twitter and eye strain.
  • Offers clearer and faster results for scaling to higher resolutions than its equivalent interlaced video, such as upconverting 480p to display on a 1080p HDTV.
  • HDTVs not based on CRT technology cannot natively display interlaced video, therefore interlaced video must be deinterlaced before it is scaled and displayed. Deinterlacing can result in noticeable visual artifacts and/or input lag between the video source and the display device.
  • Frames have no interlace artifacts and can be captured for use as still photos.