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conforming multiple frame rates 18fps and 24fps
I have a complex issue that I have yet to find an answer for. Due to some technical problems while on a shoot, I was forced to film some 8mm stock at 18fps. Before and after the problem I shot at 24fps with a crystal synch device to ensure there wouldn’t be any audio problems.
Here’s the issue: the processed film was transfered to mini DV at 29.97fps, which includes the film shot at 18fps. The difference is that film shot at 18fps doesn’t get the standard pulldown. Instead, a 4:3:3 pulldown is applied to bring it up to 29.97fps.
Basically, I want to remove the pulldown on all the 29.97fps footage and be able to edit it on a 23.98 timeline. Obviously this would require pushing the 18fps footage up to 23.98 using some other (unknown) pulldown. Otherwise, I’m stuck in a 29.97 hell (haha).
Does anyone know how to remove this uncommon pulldown? Secondly, does anyone know any method of converting 18fps footage to 24fps?
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5 Replies
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That’s a tough one to answer. Try this: Google and download JES deinterlace. Rather than trying to do a reverse telecine, just use JES to do a regular smart deinterlace. Then you’ll have clean 30p footage to work with and no worries of mixed field issues.
Now that you have progressive-scan footage, you could drop it in a FCP sequence (23.98), render it, and export a self-contained QT. This would essentially remove 6 frames every second in even intervals. I haven’t tested it or done the math, but I believe that would leave your true 18fps intact. So you’d be good to go. Try it out.
Sean
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Thanks Sean, I’ll give that a try. My only follow up question would be: how is the smart deinterlace is creating progressive frames?
I would assume it’s blending the fields of the interlaced frames into one progressive image, which would probably result in a slightly blurred frame.
The fact of the matter is that not every frame is going to be crisp when I’m trying to turn 18fps to 24fps, unless I duplicate 6 frames per second. Do you know of any software that allows you to remove specific frames and/or duplicate specific frames?
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[Mike Mallen] “I would assume it’s blending the fields of the interlaced frames into one progressive image, which would probably result in a slightly blurred frame.”
No, it only does this if you select the blend fields option in the “Project” . Instead choose “Use bottom field” and make sure “Adaptive” is checked. It will perform a proper weave deinterlace (combining matching fields while throwing away frames with mis-matched fields).
On the input tab, there are options to “remove jaggies” and “reduce noise”. You can experiment with those if you want.
Sean
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I tested the software, it worked well. Thanks!
I also used it for doing a reverse telecine on my 24fps footage, it was simple and quick. I like that it doesn’t require you to tell it what the cadence is.
As far as the 18fps, it successfully created 30p media. After exporting from a 24fps sequence, what I got was 3 progressive frames followed by a 4th frame duplicated from the 3rd.
Thanks again.
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Awesome, glad it worked out!
[Mike Mallen] “I like that it doesn’t require you to tell it what the cadence is.”
It’s actually a lot more powerful than that. It can detect and fix cadence breaks within the video. And because it’s so lighting fast, I’m guessing maybe it re-works the field structure and framerate without re-encoding the video. So this has a huge advantage if you’re using a lossy codec.
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