Field Dominance Question

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dmchord

Active member
So I thought I screwed up big time.

I shot a wedding to P2 at 480i/24p. (Only one card, so I wouldn't have had space to shoot 720.)

I brought the footage into FCP on a 29.97 timeline (because, hey, that's what you gotta do when you shoot 480i, right?) Anyway, it was crazy messed up. Flickering like a candle on crack. 3 good frames, 2 frames with jagginess and so on all the way across the board.

Now, I know just enough to know that there's some pulldown action going on, though I don't really understand it enough to be of any use. The sequence was set to lower field first, and I started playing around with that. First I tried upper first, and nothing changed. When I changed field dominance to none, the problem pretty much disappeared.

My first question is, why? I really do want to understand this better. The second question is, is there anything I need to be aware of when I send this to compressor for the QT file and for the DVD? I'm still editing, so I haven't got that far yet.

Thanks in advance,

David
 
If you shot 480/24p it was progressive and not 480i. Your timebase should have been 23.98 (23.976), not 29.97. The field dominance is none with progressive footage.
If you want to shoot standard DV 480i, then use 29.97 and a field dominance of LOWER.
 
Thing is, right there in the HVX the record setting says 480i/24p. Also, I've been told that when you shoot DV, you're running 29.97, the 24p effect is some kind of pull down magic. In any case when I transferred the footage from the P2 card it came into Final Cut Pro as 29.97.
 
Yeah, I believe you're right about that now that I give it more thought. Panny uses funny terminolgy with that HVX and I think their reasoning is that you are recording 24 frames over a 60i stream...hence the 480i24p. It's been a while since I shot DV but last year I did a 24p SD project and as I recall I was able to use 24pA. In FCP I believe I selected the option in L&T to remove advanced pulldown and duplicate frames. The clips did come in as 29.97 and they played pretty smooth...so maybe you had some duplicate frames still in your clips causing the jerkiness in playback. Hope any of this helps and sorry for the earlier misdirection !
 
First of all, you should know that when you shoot 24p video, it's actually 23.976fps.
The 24 frames fit into a 60i stream (actually 59.94i) so you can feed a real-time NTSC out with Firewire.
That works fine, but you have to remove the extra frames, which is called "removing pulldown".

You can remove the extra frames either when you capture or afterwards.
To do it when you capture, choose Audio/Video Settings > Capture Preset and edit your DV NTSC capture preset
so that the Remove Advance Pulldown and/or Duplicate Frames is checked.
You can also do it in the Browser after capture. Just select the clip, and choose Tools > Remove Advanced Pulldown.

Of course, if you really want to save storage space, shoot at 24PN. That way you record
only the 24 frames per second. There are no frames added.

Finally, when you first create your sequence (before it has any clips), you can choose Sequence Settings
and select a timebase of 23.98.
 
Last edited:
dmchord said:
Thing is, right there in the HVX the record setting says 480i/24p. Also, I've been told that when you shoot DV, you're running 29.97, the 24p effect is some kind of pull down magic. In any case when I transferred the footage from the P2 card it came into Final Cut Pro as 29.97.
Click to expand...

It's 23.976 progressive until it's recorded; then it's recorded in a 60i stream. But it's no gimmick or "magic." Pulldown is only inserted in order to conform 23.976 into the 60i stream. It doesn't create 24p.

Most NLEs will detect the 24p footage and remove the pulldown automatically, but if you're using FCP, then you need to shoot 24pA (not 24p) and remove the pulldown upon ingesting into FCP.

If you shoot 24p instead of 24pA, then you have to remove the pulldown manually in Cinema Tools.

Or, you can just edit on a regular NTSC timeline, but that won't give you the best results you can get with 24p footage.
 
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