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What is Pulldown?


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#1 Tina Zito

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Posted 21 May 2008 - 07:56 PM

I was looking up HD camcorders, and the review I read mentioned 24p vs 30p. It said that 30p was better if you didn't know how to work pulldown. A quick google search told me that pulldown has something to do with the way the image is processed...

In short, what is pulldown?
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#2 Adrian Sierkowski

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Posted 21 May 2008 - 08:13 PM

pulldown is a way of capturing 24fps images onto a 60i system (which is video).
Film is 24fps (well 23.97 and some change), whereas video, like on TV and in the SD world is 30FPs, which is broken into 2 fields and then interlaced (60i). Obviously there is a problem here in getting the film speed images into the video speed. This is where pulldown comes in.
There are 2 types, 2:3:2:3 and 2:3:3:2 (advanced). All it means is that the video camera is taking 1 frame of film and making 2 fields of video, then 1 frame for 3 fields of video than 2 fields again. the 2:3:3:2 is for when you're shooting for a 24P timeline, and is intended to be removed, whereas the 2:3:2:3 is for a 60i timeline (in editing) where you leave it.
Say you have a ball, for 1 frame, and the next frame is a cat, and the next a ball again. with pulldown it would be, [] is one frame of video:
[ball ball],[ball cat] [cat cat] [ball ball], and contining, [cat cat] [cat ball] [ball ball]. and so on forever. (that's the 2:3 pulldown at least as far as I know it)
In just though its a way of making 24fps footage play "nice" with 60i video.
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#3 Tina Zito

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Posted 22 May 2008 - 12:28 AM

Thank you for your thorough reply.

Although, I am uncertain as to what a 'field' is-

"which is broken into 2 fields and then interlaced (60i)" -is a field different from a frame? how so?
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#4 David Mullen ASC

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Posted 22 May 2008 - 12:47 AM

In interlace scan video, a frame of video is made up of two fields, each containing every other scan line of the total frame. See:

http://en.wikipedia.org/wiki/Interlace
http://www.mir.com/DMG/interl.html
http://www.maxim-ic....note_number/734
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