Frame rate (also known as frame frequency) is the frequency (rate) at which an imaging device produces unique consecutive images called frames. The term applies equally well to computer graphics, video cameras, film cameras, and motion capture systems. Frame rate is most often expressed in frames per second (FPS), and is also expressed in progressive scan monitors as hertz (Hz).
24p is a progressive format and is now widely adopted by those planning on transferring a video signal to film. Film and video makers use 24p even if their productions are not going to be transferred to film, simply because of the on-screen "look" of the (low) frame rate which matches native film. When transferred to NTSC television, the rate is effectively slowed to 23.976 FPS (24×1000÷1001 to be exact), and when transferred to PAL or SECAM it is sped up to 25 FPS. 35 mm movie cameras use a standard exposure rate of 24 FPS, though many cameras offer rates of 23.976 FPS for NTSC television and 25 FPS for PAL/SECAM. The 24 FPS rate became the de facto standard for sound motion pictures in the mid-1920s.[2] Practically all hand-drawn animation is designed to be played at 24 FPS. Actually hand-drawing 24 unique frames per second ("1's") is costly. Even big budget films usually hand-draw animation shooting on "2's" (one hand-drawn frame is shown 2 times, so only 12 unique frames per second)[3][4] and a lot of animation is drawn on "4's" (one hand-drawn frame is shown 4 times, so only 6 unique frames per second).
30p is a progressive format and produces video at 30 frames per second. Progressive (noninterlaced) scanning mimics a film camera's frame-by-frame image capture. The effects of inter-frame judder are less noticeable than 24p yet retains a cinematic-like appearance. Shooting video in 30p mode gives no interlace artifacts but can introduce judder on image movement and on some camera pans. The widescreen film process Todd-AO used this frame rate in 1954–1956.[5]
From Wikipedia
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