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23.98 / 24fps - What's the difference?


Bioskop.Inc

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So on BM cameras you get the option of 23.98 & 24fps, so what's the real difference & why would they give you both - I mean 0.02fps can't be generate that much of a difference.

I ask because I always thought that 24fps was really 23.98fps, or is 24fps a digital thing & 23.98fps is a celluloid?

 

I know its a pretty basic question, but before I film a String Quartet tomorrow,  I thought I'd ask the question.

 

 

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24 fps is for going to actual film. If you want to print your digital back to film us this.

 

23.98 was a way of squeezing into 60hz so things stay synced that's stuck with us. But Blu Ray supports both.

 

It was a bit of fudging for NTSC power when analogue TV moved from black and white to colour. There was some sync issue with the signals. Then it kinda stuck.

 

So use 23.976 or 23.98 or however it's put to be safe, unless you're going to turn it into real celluloid at some point.

 

Or if it's web only and you're not shooting under 60hz lights (or you have flicker free lights) you can use 25fps for example.

 

Though 25fps won't fit on Blu Ray. It turns into 50i or something. But who really cares about that ;)

 

600Hz as a standard for TV would solve it all and finally render any content playable on any system. Except 23.976 though. Hmm. That's a pretty fast refresh rate though.

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I ask because I always thought that 24fps was really 23.98fps, or is 24fps a digital thing & 23.98fps is a celluloid?

 

The other way around. Analog film was always 24 fps, 23,97something was 99,something the speed of native film cameras. This has to do with the power frequency in the USA and other countries and NTSC television. With progressive video, there is not much to worry though. In PAL countries, the 50Hz frequency made 25fps the standard. For TV and DVD, the 24p films where just sped up, so they were exactly 4% shorter (in former times, the pitch changed slightly, and people with absolute pitch heard that the music was in the wrong key, this of course is corrected nowadays). So changig the frame rate doesn't swallow a single frame, it affects the duration of the feature and the sound. But of course, if you know you shoot for DCP, use 24p, blu rays officially support both frame rates (as 1080p). And television? I don't know. As of now, frame rates for youtube and vimeo are limited to 30fps, but otherwise you have free choice. 

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I mean 0.02fps can't be generate that much of a difference.

 

In fact, just the difference between 23.98 (what final cut is using ) and 23.976 (what everything else is using) is quite big. When you have time code burn in your footage and when you are starting your edit at 10:00:00:00, you can have a lot of frame differences here and there.

 

Had this problem 2 years ago when a client worked in fcp (23.98) gave me the project so i can import it in AE (in 23.976)... lost a few days of work when I saw everything was off-sync (a 1h30 feature film with hundreds of cuts)

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In fact, just the difference between 23.98 (what final cut is using ) and 23.976 (what everything else is using) is quite big. When you have time code burn in your footage and when you are starting your edit at 10:00:00:00, you can have a lot of frame differences here and there.

 

Had this problem 2 years ago when a client worked in fcp (23.98) gave me the project so i can import it in AE (in 23.976)... lost a few days of work when I saw everything was off-sync (a 1h30 feature film with hundreds of cuts)

Lucky i work with FCP then!

So do you think i should use/keep to 24fps when i know the projects will go somewhere else?

 

Love this place, loads of info just being handed around!

Thanks!

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Lucky i work with FCP then!

So do you think i should use/keep to 24fps when i know the projects will go somewhere else?

 

Love this place, loads of info just being handed around!

Thanks!

In fact, 23.98 (like FCP) is really wrong - the real one is 23.976 (and something...). At first, I tought it was only the rounded number being displayed, but it is not.... if you ever have to convert to another editor, make sure you triple check your edit with a rendered version....

 

got the problem with automatic duck - there is a free ae script somewhere if I remember that interpreted correctly the 23.98 to 23.976.

 

As for 24p vs 23.976, it really depends on the final destination : TV : 23.976, Cinema : 24, everything else : you choose....

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In fact, I am not sure if it was FCP actualy working in 23.98, or FCP writting 23.98 in the XML instead of the real speed with precision that messed up everything. (I read that resolve also have difficulty with FCP 23.98, not just automatic duck)

 

So I just created a 02:00:00:00 comp in AE, one at 23.976 and one at 23.98,

23.976 = 172799 frames

23.98  = 172655 frames

 

If someone can create a timeline in FCP and confirm one or the other, it would be nice...

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