Motion interpolation

Motion interpolation or motion-compensated frame interpolation (MCFI) is a form of video processing in which intermediate animation frames are generated between existing ones by means of interpolation, in an attempt to make animation more fluid and to compensate for display motion blur.

Motion interpolation is a common, optional feature of various modern display devices such as HDTVs and video players, aimed at increasing perceived framerate and/or alleviating display motion blur, a common problem on LCD flat-panel displays.

A display's framerate is not always equivalent to that of the content being displayed. In other words, a display capable of and/or operating at a high framerate does not necessarily mean that it can or must perform motion interpolation (most TVs ship with any such feature enabled by default). For example, a TV running at 120 Hz and displaying 24 FPS content will simply display each content frame for five of the 120 display frames per second. This has no effect on the picture other than eliminating the need for 3:2 pulldown and thus film judder as a matter of course (since 120 is evenly divisible by 24). Eliminating judder results in motion that's less "jumpy" and which matches that of a theater projector. Motion interpolation can be used to reduce judder, but it's not required in order to do so.

The advertised framerate of a specific display may refer to either the maximum number of content frames which may be displayed per second, or the number of times the display is refreshed in some way, irrespective of content. In the latter case, the actual presence or strength of any motion interpolation option may vary. In addition, the ability of a display to show content at a specific framerate does not mean that display is capable of accepting content running at that rate; most consumer displays above 60 Hz do not accept a higher frequency signal, but rather use the extra frame capability to eliminate judder, reduce ghosting, or create interpolated frames.

...
Wikipedia