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Old March 24th, 2009, 06:56 PM   #1
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What Does 24p in an i60 wrapper mean?

Sorry, I am confused.

I am shooting with a Canon HF100. I have been using the 30p setting and then editing in Final Cut Pro. It works great. I would also like to try 24p. But when I am reading that these are not true progressive but in a "wrapper", what does it actually mean and is there anything I need to do to get true progressive when I edit.

Also, I have been converting my final cuts to Flash for the web. I have not been "de-interlacing" in this process and it looks great. Am I correct in doing it this way?

Thanks!
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Old March 24th, 2009, 08:15 PM   #2
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woops, meant to say 60i wrapper.

there was another post about 24p below, but it did not explain what the "wrapper" is.
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Old March 25th, 2009, 08:30 PM   #3
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It's not a "wrapper" in the sense of a certain codec being "wrapped" inside a file format, like .h264 "wrapped" in *.mpg or *.mov. In these cameras, ALL the footage is recorded as 60i. The 30p records one full frame as an odd and an even field; this is often referred to as progressive segmented frame (PsF). The 24p has one full frame recorded across three fields (either two odd and one even, or one odd and two even), and the next frame is recorded across one odd and one even field. This is referred to as 2:3 pulldown and keeps the overall timing correct. It works out if you do the math:

(3 fields/frame x 12 frames/sec) + (2 fields/frame x 12 frames/sec) = 36 fields/sec + 24 fields/sec = 60 fields/sec

The other common flavor of pulldown is 2:3:3:2 and these cameras don't use that.

I don't use FCP, but I'd assume that it has algorithms to sense 2:3 pulldown and re-assemble the fields into the proper frames on the timeline without you having to do anything, as most current pro-level editing software does. If not, then you just have to tell the software what the repeat pattern and give it a reference point for where one frame ends and the next begins. Can't help you with how FCP does that. I'd say just shoot a couple of 5-10 second test clips in 24p and try them in a new 24p FCP timeline.
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Old March 25th, 2009, 08:39 PM   #4
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It appears that it shoots in 24p and then does a 3:2 pulldown converting it to 60i so it will work with regular TVs. If you need to get to just 24p, you have to do a reverse pulldown.

Check this: Adobe Forums - Speeding up Video makes it look interlaced
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Old March 26th, 2009, 03:32 PM   #5
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Quote:
Originally Posted by Michael Murie View Post
It appears that it shoots in 24p and then does a 3:2 pulldown converting it to 60i so it will work with regular TVs. If you need to get to just 24p, you have to do a reverse pulldown.

Check this: Adobe Forums - Speeding up Video makes it look interlaced
That's the crucial step. You must do something -- what you do depends on your NLE -- to remove the 2-3 pulldown to get 24p video to edit in a 24fps timeline.

If you don't do something -- you can still edit in a 60i timeline. However, as you cut, you'll break the 2-3 cadence of each clip. Do you care? Very likely not.

Will your audience see 24fps -- like the Hertz ads -- "not exactly." Let's say it will look "different."

A better option is to shoot 30p. Now you can edit in a 60i timeline and really get 30fps movies.
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