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Frame Rates in Post


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#1 David Osborne

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Posted 11 May 2007 - 12:22 PM

Let's say you shot some action in 720p with the variable frame rate set to 32, then you bring it into post on FCP pro and you're watching and you think, man I kind of want it to be slower (like as if I shot 48 fps) or faster, whatever. Since the camera is recording 60p (when not in native mode) there is 60 frames worth of data per second there right? So you should be able to play it back as if you shot anywhere between 0 and 60 fps?

Is there any way to change the frame rate (way that the frames are flagged) after the fact?

Can you do it easily is another question, because there are some miserable ways I can think of to accomplish this "retro-active frame rate control" but I wouldn't want to do it; like manually slicing individual frames from a 60p timeline then sequentially deleting or keeping ones you want in ratio to the speed you desire then plopping it in a 24p timeline :o

So again, basically my question is, can I just shoot 720/60p at 60 fps all the time and decide later how I want the frame rate to be? :rolleyes:
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#2 Greg Johnson

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Posted 11 May 2007 - 12:53 PM

Hey Dave,
My understanding is that in 24P (non-native) it does record 60FPS. But only 24 frames of them are unique, meaning that there is approximately 24 sets of 3 duplicate per second. 20x3 = 60fps.

Now you can do what you suggested by shooting everything at 60p, then decide later how you want to play it back. Problem is you'll end up truncating some frames and your motion may end up uneven and/or strobey. (But if you're doing an action scene, at a high shutter, who's to say that's bad?)

You don't need to manually cut the frames out, if you just drag a 60P file into a 24P sequence FCP will do all that for you. I've done it many times and haven't ever really considered it a problem. Then to interpret the footage I use Cinema tools, I don't like the panasonic tool, it's too buggy.

My biggest problem with shooting all at 60p is amount of info it takes up. So usually choose my frame rate on a shot-by-shot basis.

I made a series of paintball videos with this technique, (shooting at 60p then playing back at 24p). I even mimicked some speed ramps. Check it out if ya want: Blackcell Trilogy

- Greg
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#3 David Osborne

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Posted 11 May 2007 - 03:30 PM

Hi Greg,

Thanks for your post, and your videos look great; really nice high contrast and I love the selective focus. I like the ramp when the guy crosses that opening in the wall, that's exactly the type of freedom I'm looking for in editing.

I don't think I mind having the shutter speed appear high/"strobe-like", I guess only experimentation will tell. Also I won't necessarily be shooting 720/60p/60fps all the time, just for shots when I know I want to overcrank the camera, but don't really know how slow I'll want the motion to appear in the end.

One of these days I'll get around to posting some of my stuff on the web...

Thanks again,
Dave
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#4 Ken Minehan

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Posted 15 May 2007 - 10:10 PM

Hi guys, i have a question for you with regards 60p (where i'm from 50p). After you shoot 720p60p, and you bring it in to your FCP, do you have to make adjustments to your sequence setting? If so what are they?
Are you guys shooting with the firestore or p2 card.

Thank you guys
Ken Minehan
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#5 Greg Johnson

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Posted 24 May 2007 - 09:36 PM

Hi guys, i have a question for you with regards 60p (where i'm from 50p). After you shoot 720p60p, and you bring it in to your FCP, do you have to make adjustments to your sequence setting? If so what are they?
Are you guys shooting with the firestore or p2 card.

Thank you guys
Ken Minehan


Ken,
If you want to play 50 fps then just create a sequence in FCP. IF you want to play it back at 25P then you'll need to conform the frame rate. Don't adjust the speed in FCP, it won't work.

After I've imported the files into FCP I save the project. Then select your clip and option click "revel clip in finder". This will pull up the root file in finder. (I'm a back up geek so I never mess with the original file - if you do mess with the original it'll go off line once you've altered it. )

Anyway, copy and paste (duplicate) this file in the same directory so you're not altering the original. Then I option click and "open with" cinema tools. Once the file is in Cinema tools click the "conform" button then select 25 (or whatever) frames per second. Close out and now your file has been altered. I usually create a "over crank" bin in my FCP project, then import all my conformed files there.

Panasonic also makes a plugin you can download for free that'll allow you to do all this in FCP, but I haven't had much success with it.

You can also use Affter Effects to interpret your footage, but you'll have to render out your changes.

Hope that helped, PM me if you still have trouble.

- Greg

Edited by Greg Johnson, 24 May 2007 - 09:39 PM.

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#6 Ken Minehan

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Posted 14 June 2007 - 01:16 AM

OK, thank you very much greg. It works like a dream. There is one thing though, do you get the strobing effect when it's shot on 50p. It doesn't seem like a clean slo mo. Or is this how it's supposed to be? The picture is slowed down, but the moving portions of the frame is a bit blurred.

regards
Ken Minehan
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