Removing 4:2 Pulldown in Seven Easy Steps

Removing 4:2 Pulldown in Seven Easy Steps
Removing 4:2 Pulldown in Seven Easy Steps

Referencing my original post on the subject, I finally found a solution to removing a 4:2 pulldown from a 30i clip, to get back to a 25p clip. It’s not pretty, but if you’re interested in the tech stuff, read on…

The solution did, indeed, involve Windows (in my case, running on Virtual PC 7) and the freeware apps AviSynth and VirtualDub. These steps assume that you’re working with a QuickTime file from which you need to remove this pulldown.

  1. Prep your Windows machine (real or Virtual PC) by downloading AviSynth, AVSEdit (at the bottom of the AviSynth downloads page) and VirtualDub from the links above, and install them.
  2. Make sure that your clip starts on an “A” frame, where the cadence is “AA BB CC CD DE EE”.
  3. Open your movie in QuickTime Player, and File > Export… with Movie to AVI. Make your video settings Compression: None; Depth: Millions of Colors; Quality: Best. I didn’t bother with exporting sound, as my clips didn’t need it I’m not sure how the audio would fare through this process, but I’m betting not well. If you have audio, I’m guessing it would be better to strip it out here, and sync it back up later.
  4. Bring the AVI onto your PC, or on the same Mac that’s running Virtual PC. You’ll want to note the full pathname of your clip, from whatever random letter VPC has assigned the drive your clip is on.
  5. Open up AVSEdit, type this code and save

  1. Open VirtualDub, and open the AVS script that you just saved, then select File > Save as AVI… (F7) and save your new clean AVI.
  2. Bring your AVI back into QuickTime player, and File > Export… as a QuickTime Movie. You’re done!
  3. One additional step for me, since I needed to get back to a 24fps clip for inclusion in a 720p24 show I’m working on—- Bring the new QuickTime clip into After Effects, and File > Interpret Footage > Main… and set Conform to frame rate: 23.976

It’s pretty convoluted, but it works. What amazes me is that there’s no tool like this that exists for the Mac. Guess it’s time for me to get back to my programming class, eh?