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Pulldown from 18 fps to 24 fps


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#1 Nima Khazaei

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Posted 30 May 2015 - 10:28 PM

Hello everyone!

 

I'm really new to filmmaking - I've been reading up for several months, and I just finished shooting my first film! It's a silent short shot on my friend's Bolex, on Tri-X Reversal.

 

For reasons I now slightly regret, I shot at 18 fps. Mostly, I had fallen in love with the look of old silents projected from celluloid, and didn't mind the 25% savings on stock and processing.

 

I had the film scanned so that I could edit together a digital video, but I'm having a lot of trouble working with the fact that it's 18 fps. The scan from the lab came one video frame to each film frame, as expected, but I want to do a pulldown to a standard video speed like 24 fps.

 

I've been banging my head against Google trying to figure out how to do the conversion, and so far have had no luck at all. If I'm understanding this correctly, it seems like it should be a pretty easy pulldown, just displaying every third frame twice to produce 24 frames from 18.

 

I would really appreciate it if someone could recommend a technique for doing this conversion. I'm using AVID, which doesn't seem to have the functionality built-in (or at least I couldn't find it). The file I'm working with is a ProRes 4444.

 

Thanks in advance for your help!

 

—Nima


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#2 Nima Khazaei

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Posted 31 May 2015 - 04:05 AM

Ah! Found the Motion Effect Editor, which seems to have options to adjust speed by duplicating frames, duplicating fields, and interpolating. I picked "Both Fields" since there shouldn't be any inter-field activity given that my video isn't interlaced at all. I'm assuming this option will just duplicate every third frame.


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#3 Phil Rhodes

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Posted 31 May 2015 - 06:40 AM

You've made a bit of a problem for yourself there. Just duplicating every third frame is going to create some fairly noticeable motion artifacts. You might try a more intelligent interpolation, such as Twixtor's, but there are downsides to that too. In the best case it'll make your material look like it was shot at 24fps, although there can be unpleasant artefacts and grainy black-and-white small-gauge film is a tough target for it. If you can upload a brief shot somewhere I'll try it and see what we end up with!

 

If you want it to look like a silent movie, though, perhaps live with the speedup. It's probably not accurate, but it might have the right sort of look subjectively.

 

P


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#4 Nima Khazaei

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Posted 31 May 2015 - 07:14 AM

Hi Phil! You're right, the motion is indeed a bit choppy... it's not so bad that I couldn't live with it though. There may not be a single entirely perfect solution, but that's alright since I'm also going to splice the actual 16mm film together, and I can just consider that to be my true finished product.

 

If you wouldn't mind, I would certainly like to see how it looks motion-interpolated up. I'll upload some clips to my Dropbox in the morning - it's 5 AM now where I am, I've been editing all night and at the moment I'm quite tired of Avid and consciousness in general...

 

Thanks for your help!! Massively appreciated!

 

—Nima


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