Me in the News

Digital Content Producer wrote an article about HD movies at Sundance last month and I just stumbled across it online while actually searching for the other Kyle Gilman who plays baseball and enjoys “Second Life.” The author interviewed me via email and I had a lot to say about HD. Much of it shows up in the article.

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.