Frame rate is also known as frame frequency or frames per second (FPS). It is the frequency or rate at which the imaging device produces unique successive images. Those images are called frames, and thus frame rate gets it name. It is a count of how many images a movie displays per each and every second. As a matter of fact, a frame remains still but visible image. However, we have the impression that the movie is showing us a motion picture. The reason is that the image is displayed in rapid succession, which creates the illusion for us. The term also applies to film and video cameras, computer graphics, and motion capture systems. Frame rate describes the speed of both recording and playback. Generally speaking, the more frames recorded per second, the more accurate motion is displayed on the screen.
Under most of the circumstance, recording and playback are of the same speed although it is not necessary. However, on the other hand, if you play back frames at a speed different from that of the original recording, then some potential problems may come into being. For example, some temporal effects such as time lapse and slow motion may emerge, which could bring some unexpected damage to the video quality.
Moreover, different content has different numbers of FPS. The different FPS can be classified by the part of the world from which the DVD comes, the way in which the content is recorded, or the way that the DVD is mastered.
In conclusion, frame rate is the number of the frame or the image projected or displayed in motion pictures, television, and in computer video displays. The more frames or images are recorded per second, the more vivid and clear picture people will enjoy on the screen.