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How to grab every nth frame of video?
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Sep 28, 2003, 05:09 PM
 
For those of you video-savvy folk in this forum, I have a question: How would I capture every nth frame of video? I have a VHS tape with about 8 hours of footage. I want to build a QT movie for a presentation that shows 1 frame for every minute of real time. (every 30th frame or so). Running this QT movie at 30 FPS would show an interesting time-lapse effect.

VHS -> DV -> iMovie ?
VHS -> DV -> QuickTime?

Not sure which software to use to sub-sample in this way.

Thanks in advance for any suggestions.
(Last edited by one09jason; Sep 28, 2003 at 05:36 PM. )
     
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Sep 28, 2003, 06:33 PM
 
you mean one frame for each second? or one frame in 180 for one per minute? either way, what I would do is import to DV, open in QTMutator, set the movie duration to whatever it is divided by whatever you want, and save (or you could copy the length you want the final to be in QTPro, Add Scaled the original to that, and delete the short track). This will give you a movie with the speed you want but way too many frames per second. Then export from QTPro to your delivery format, setting the framerate under Options -> Video -> Settings. This will do a "hard" framerate change, discarding the extra frames.

The hard part of course would be the 8 hour input. You could do it in chunks, but I would do it overnight in an app like BTV ($20) that can compress on the fly to something like 3ivx or Apple's mpeg-4 codec. If you were doing any editing, you would be a fool to compress during capture, but in this case I think it will be a good move.
     
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Sep 28, 2003, 06:53 PM
 
Huh. Ok, sounds like a plan. If I do it in chunks, then how could I merge them together later ? QT Pro again?
     
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Sep 28, 2003, 08:41 PM
 
yes QTPro. It usually works, but every so often I get two chunks that don't play smoothly when pasted together, so I try to avoid depending on that when possible.
     
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Sep 29, 2003, 10:54 AM
 
heh, should have checked versiontracker first. there's one on the front page today called DVTimeLapse, which seems to be just what you want
     
   
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