24p Headaches

I got an email from my old friend Mr. Taj Musco last week. I made my first real movie “Is This the Pizzaman?” with Taj after my freshman year of college. It was shot on S-VHS and edited tape-to-tape at our local cable access facility.

Taj was having trouble with some footage he shot in 24p advanced that was getting all wonky when he made a DVD or output to DV. Taj is a smart guy, and he had troubleshooted like crazy, but he was stumped. I also used to see a lot of confusion about 24p on the Apple FCP forums when I used to frequent that place. There was one heartbreaking story of an assistant editor who had captured PAL tapes at 24fps thinking that the timecode would match their masters when it was time to online. They didn’t. Don’t do that. Edit at 25 fps.

Here’s the thing. Editing in 24p is endlessly confusing. Let’s start with the term 24p. It means two different things! It can mean 24.0 fps, which is the speed that film runs at, or it can mean 23.98 fps, which is the speed that NTSC video runs at. If you shoot any 24p on a video camera, you’re shooting at 23.98 fps. The exception to that is HDCAM format, which can shoot at 24.0 fps. But the only good reason I can think of to do that is if you’re mixing it with mostly film footage.

Let’s assume for the moment that you shot 23.98 video. Most of you reading this did that. If you didn’t shoot HDCAM or on an HVX-200 (a camera which will get its own post soon) then what you actually have is regular old 29.97 NTSC interlaced video.

“But! BUt! BUT!” You shout. “! Didn’t I shoot 24p? I want to be like a real filmmaker and junk.” Yes you did. But DVCPRO and DV tapes record NTSC or PAL video. What the camera does is the same sneaky trick that you do in telecine. It’s called pulldown. It takes those 24 frames and spreads them out into 30. It doesn’t just play them slower, because that would look like slow motion. Instead it duplicates some of the 24 frames in a set pattern. It’s beyond the scope of this post to explain how it works. Look up telecine in wikipedia. It’s fascinating stuff if you’re a huge nerd like me.

If you’re working in Final Cut Pro, you DON’T CAPTURE 23.98 VIDEO. You capture regular old NTSC. If you shot 24p “advanced” then you capture NTSC but turn on the check box for removing advanced pulldown. Then you EDIT at 23.98 because your clips have been converted back to 23.98 during capture. If you shot in regular 24p, then capture NTSC and use Cinema Tools to remove the pulldown. If all goes well you should be able to just do a batch reverse telecine and then reconnect your clips to the new ones.

It’s a really good idea to check your clips at this point for any remaining interlaced frames. If you’re playing out to an NTSC monitor you’ll see it right away. It stutters like it’s duplicating half-frames, which is exactly what it’s doing. You’ll see it right away. If you’re poor and don’t have a way to output to an NTSC monitor, just open up some of your clips in Cinema Tools and step through the video using the left and right arrow keys. Try it on a part of the clip with lots of movement. If you see any interlacing at all you’ve done something wrong. Don’t start editing until you see only progressive frames.

And just to clear up some confusion, there is no real difference between footage shot in 24p advanced and 24p regular. It’s only a question of the workflow outlined above. You can easily blow up either one to film assuming you’ve removed the pulldown properly.

6 replies
  1. Johannes
    Johannes says:

    So, I’m editing a project shot on the DVX100 in Advanced 24P mode.
    As I understand it my work flow should be…

    1. capture DV NTSC – (2:3,3:2) removal
    2. reverse telecine all clips in Cinema tools
    3. bring all the fixed clips into a 23.98 sequence for editing

    Thus far, I have done a test this way and I have gotten all progressive frames that I can view on my DVNTSC deck. So cool.

    I wonder about delivery format though. Assuming I continue this route; what output formats will be available to me? Video for DVD? And will film be possible?


  2. Kyle
    Kyle says:

    We cleared up Johannes’s issue over email. It turns out the footage was not 24p advanced. It was just regular 24p. You should only have to do either step 1 or 2. Never do both.

  3. Julie Espinosa
    Julie Espinosa says:

    kyle gilman, holy shit! I read this entire post *twice* (and still didn’t fully understand it) before realizing that it was written by you. small world. 🙂

  4. steve
    steve says:

    Great explanation of workflow that I have not found elsewhere, even in FCP forums! One problem: I understand that I have do the pulldown with my Sony V1U footage, but that’s only camera B! Camera A was a Canon XH-A1 that shot at 24f. By looking at it, it does not need a pulldown and is captured at 29.97. How do I edit my camera B stuff on a 23.98 timeline and combine it with my Camera A on a 29.97 timeline all for a final export on DVD? Talk about headaches! Thanks.


  5. Kyle
    Kyle says:

    I haven’t worked with either of those cameras, but if both were really shot in 24p, then you need to remove pulldown from the footage of both cameras. Do not try to edit one at 29.97 and one at 23.98. You’ll end up with a lot of rendering and crappy looking video. The other option is to not worry about removing pulldown at all and edit everything at 29.97. You will likely never see a difference between that and editing at 23.98.


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