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Converting animation & audio from 24 fps to 25 fps
Hi,
I know this topic has been done to death but I can’t find any answer to my problem. Basically I work in an animation studio that’s producing a tv series with the help of a production house abroad. We were creating animatics & audio at 25 fps and they animated in 24 fps. We have decided to conform the animation to 25fps using Cinema Tools. However when we brought the uncompressed quicktime movie into Cinema tools the comform button was greyed out – I know this is probably me doing something incredibly stupid and I’m sorry if I waste your time but can anyone tell me what I’m doing wrong? Can you actually convert 24 fps to 25? or is it only the other way around?
Thanks so much!
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26 Replies
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Of course you can convert from 24 fps to 25 fps. The question is whether you can stomach the result.
The simplest way to do the conversion is to double one frame every second. The eye can catch this. Next you can try doubling one frame at not exactly one second intervals, to break the rhythm. The eye can still catch it. Next you try introducing a frame blended from two neighbor frames. This is shockingly apparent, especially in animation. Next you interpolate the whole thing: after the genuine frame 1 you create frame “1.96”, then frame “2.92”, etc. Your interpolation algorithm had better be damned good, because you’re creating 24 out of each 25 frames.
Unless the animation and the animatics have to interact, why are you planning to convert the frames of either one? Why not leave the 24 fps animation frames exactly as they are and “declare” them 25 fps. This means you speed up the animation by about 4%. The sound corresponding to the animation must be correspondingly sped up by about 4%, but this is a perfect process which does not change its pitch. The animation is now 4% shorter. I hope you have some extra material in case you have a duration requirement.
It might surprise you how insensitive viewers are to 4% speed increases, even in live action. It’s funny that this is easily verified with movie film in a variable speed projector, but difficult in our computers. -
CT should work – at least it works here all the time this way.
For the audio convert you should use STP, it got some nice features to change the length of the audio, though I can’t tell you how to do, because that is always done by the sound guys (if necessary)Andreas
Spherico
https://www.spherico.com/filmtools -
Dave – Yeah! I spent all day looking at the manual. I am new to Final Cut, I mostly worked on Adobe/avid before. Basically it worked fine when I brought a 25fps animatic in, conformed it no bother, but the 24fps quicktime animation that we were sent just wouldn’t conform, the option was greyed out in the drop down and the button was greyed out at the bottom of the screen.
I’m sure it’s something really simple and I searched the internet for it before deciding to go to the experts! I was going to use Cinema Tools because I thought it might do the job a little cleaner than After Effects.
Dennis – We will probably end up doing something like that if we can
t find a better method alright – sounds like a plan, if, as you say, we can stomach the results!Andreas – We do hope that the sound company will look after the sound quality, but we have to make sure the animation syncs up, we go some lip sync issues.
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Replying to Dave LaRonde.
#1, anyone watching professionally made movies on SD TV has low quality standards.
#2, are you sure that the 24 fps movies played on European TV were converted to 25 fps PAL whole? Or was the 24 fps picture “declared” 25 fps (as per my suggestion) and only the sound converted (losslessly) to 25 fps? That would have allowed simpler film transfer hardware and produced better total quality.25 fps to 24 fps conversion is also pretty crappy, and best avoided. For example, in 2007, Fasbinder’s “Berlin Alexanderplatz” which was shot on 16 mm at 25 fps for German TV was elaborately restored for a DVD issue. They chose to not putz with the frames, but rather to “declare” it 24 fps and accept that it would run 4% longer than the original. This was a good aesthetic decision, and the flipside of my recommendation to Riana McKeith.
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Riana,
Have you checked what kind of codec the animation files do have – that might prohibit CT to make the conform.
Andreas
Spherico
https://www.spherico.com/filmtools -
Firstly for Dave & Dennis, as a telecine operator in the 1970s in a PAL country, I can assure you that the films were telecined straight off 24fps prints running at 25 fps. So they ran 4% fast and sound ran at a higher pitch.
These days it is possible to correct the pitch and the only two programs that I would recommend are Pitch ‘n Time or MPEX. I use MPEX3 and have often done final 5.1 mixes of films for PAL DVD releases. So if you are simply speeding up the 24 to 25 then the audio needs to be sped up 4% without changing pitch.
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Andreas: Yeah, that’s what I though. It was originally compressed with H.264 so I exported it as “animation” from quicktime but still had the problem. I could only assume then that the issue was that it was 24 fps?
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Riana,
Could you post just 2 or 3 frames of the movie somewhere. I will have a look.
You also could send them (zipped) to my email address: kiel(at)spherico.comAndreas
Spherico
https://www.spherico.com/filmtools -
Your picture consists of a large number of frames. Each frame is a still picture covering a small interval of time. You can display those frames at 24 per second or at 25 per second, and the show will look pretty much the same to everybody. It’ll just run a bit longer or shorter. There are some very rare individuals who can see the difference, but so far I’ve only met one.
Trying to mess with the content of the frames to make new frames for a different rate is an extremely difficult problem, and a major mistake for converting between 24 and 25. If you had to convert between, say, 24 and 30, you’d have to try it. But for this, don’t. The artifacts are always obvious.
Let your frames be what they are, and stretch or squish the sound to fit. Today, sound can be pitch shifted with excellent results.
We’ve always made major network TV shows at 24 fps, either on film, tape, or digital cameras. We sell these shows in the PAL/SECAM markets by speeding them up, but leaving all the frames exactly as they are. (They get a couple minutes more commercial inventory per hour that way.)
— J.S.
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Since Dave LaRonde thinks that Michael Gissing’s information confirms his thesis, and I think the information confirms mine, there’s a big fat confusion in here.
What I mean by converting 24 fps material to 25 fps material is adding an extra frame to the original so there are now 25 frames for each second. Frame rate conversion, in my book, means conversion without changing length (running time).
When you convert 24 fps material to 30 fps material you expect the length not to change. When you convert from inches to centimeters you expect the length not to change.
“Of course you can convert from 24 fps to 25 fps. The question is whether you can stomach the result.” I meant framerate conversion, as should have been obvious from my details. Adding an extra frame every second, even with tricks, never looks good — is hard to stomach.
What Michael Gissing describes is not conversion from 24 fps to 25 fps in the above sense. To telecine “straight off 24 fps prints running at 25 fps” means that each film frame becomes two fields of video. That is no framerate conversion at all. It amounts to “declaring” the 24 fps movie 25 fps video. It accepts a 4% length reduction, just as I suggested Riana McKeith should accept.
If you brought a 24 fps film to a cine effects lab requesting conversion to a 25 fps film, and the lab handed your film back to you saying “done”, and instructing you to project it at 25 fps and be happy, you’d be happy, but there would not have been a framerate conversion.
All of this rests on my usage of the word “convert”, but maybe Dave LaRone, and maybe even Riana McKeith, mean something different by “convert”. Maybe they mean by convert what I mean by “declare”. The guy in the cine effects lab was able to “declare” your 24 fps film 25 fps by telling you how to project it. How does one go about declaring 24p digital video 25p digital video? Who knows how to go into a header, or a wrapper, and change ’24’ to ’25’? Maybe many more numbers need to be changed. Maybe it won’t play after the changes. What a nasty medium, wherein mere formalities — “declarations” — can compete with substance.
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