Movie frames per seconds vs TV

[Bytegeist]

@Alive At Both Ends

Certainly does, but in the UK (which uses 25 fps) there’s a simple solution - do nothing at all. If a movie is shot at 24 fps and played at 25 fps nobody will notice the slight speed-up, except a few people with perfect pitch who’ll hear all sounds half a semitone sharp.

But then . . . the movie is over in 24/25ths the time it’s supposed to be! Man, what a rip-off.

Here’s a page from Kodak that summarizes why film spanks video — though they don’t seem to use that term.

[Gary_Robson]

I suppose somebody has to come in and point this out…

Our frame rate for NTSC video in the U.S. is not 30 frames per second (fps). It’s actually 29.97 fps. I interviewed quite a few old video engineers about this when writing one of my books, and I got several different explanations for this particular choice. The most prevalent was that a frame rate of 30 fps (which would be at 60 Hz because we use interlaced frames) produced a hum that was very difficult to get rid of. Changing the frame rate ever so slightly fixed the problem.

[Ximenean]

@RealityChuck

The difference in look is due to the difference in resolution of film vs. video.

If that is the case, how do you explain the failure of special effects guru Douglas Trumbull’s Showscan format? Large format 70mm film, at 60 frames per second, but he abandoned it because it looked too much like video. Maybe TV’s 60 field-per-second refresh rate is part of what makes it look different to film.

[iamthewalrus_3]

@Musicat

One thing that hasn’t yet been mentioned in this thread, but certainly belongs here, is the conversion from 24fps to 30, as in film to video. The standard method prints one frame, one frame, one frame, then two frames (of the same original image). This doubling of every 3rd frame is not significant for humans to notice, but the sound has to be slightly adjusted to re-sync, again, not noticeable.

Ahem

@iamthewalrus(:3=

When you watch a movie on TV, since they have to get six extra frames per second from somewhere, they generally just repeat one frame in every 4. It’s also possible to do some interpolated stuff, so you get partial frames that blend better, but I don’t know if that’s actually done regularly.

@InvisibleWombat

I suppose somebody has to come in and point this out…

Our frame rate for NTSC video in the U.S. is not 30 frames per second (fps). It’s actually 29.97 fps. I interviewed quite a few old video engineers about this when writing one of my books, and I got several different explanations for this particular choice. The most prevalent was that a frame rate of 30 fps (which would be at 60 Hz because we use interlaced frames) produced a hum that was very difficult to get rid of. Changing the frame rate ever so slightly fixed the problem.

My father (who has done radio/television repair and signal processing engineering for years) explained it to me as a byproduct of adding color to the NTSC standard. In order to make color broadcasts compatible with b/w TVs, they had to do some funky encoding of the color, and the frame rate was changed a bit to get rid of interference between the color encoding and some other signal. Wikipedia confirms.