Ever switched display modes or resolutions on your television or game console? You may have noticed that along with different resolutions, there is usually an additional letter after the resolution such as 1080i or 1080p. The latter is typically considered to be the better choice for a display mode, yet it is not usually made clear as to why.
The “i” in a display mode stands for interlaced and the “p” stands for progressive. The difference between these two modes is in how it refreshes what is on the screen. When running a display in an interlaced mode, when the next frame is displayed it gradually bleeds through in a linear fashion (much like one of those old transitions on Windows Movie Maker back in the day). Progressive is quite the opposite, the frames are simply displayed one after the other instead of blending the frames together. This is the primary reason that progressive display modes are usually favourable.
When running on an interlaced mode, moving object outlines and other highlights may look somewhat blurred and distorted as the frames are blended together whereas when in a progressive mode, moving object outlines and other highlights should retain a fair amount of crispness. The main advantage there used to be with an interlaced mode was whereas older progressive displays may have had lower frame rates resulting in a “choppy” image, interlaced modes removed that problem all together (because the frames effectively smoothly transitioned from one to another). Currently however, most displays are at least 60Hz, effectively eliminating the frame rate issue with progressive displays, making progressive display modes the most favourable.