Remove 3:2 Pulldown

(View fullscreen and HD to see the details. this video refers to processing clips before editing, but the same process can be used after editing. Read on for more)


If you shot at 24 FPS, but you’re editing in 29.97 FPS (check by going to Sequence > Settings in FCP, or to check your clips, right click one and choose Item Properties), it means that there are extra duplicate frames added to your footage though a process called pulldown. This happens either in standard definition telecine (see “Background” below for why) or in camera for compatibility with older systems that only know how to work with 29.97 FPS footage. Modern video systems can easily display 24P, however, and the extra frames will reduce the quality of your film.

You have two options: ideally, you should remove pulldown on your source clips before you edit. You can still do that, and relink the clips in your edit to the new files—but this may throw some of your edits out of alignment. For example, if you made an edit at a timecode like 1:23:25, after processing, frame 25 will no longer exist! You could also process the edited file you export out of FCP. The drawback is that anywhere that had transitions, superimpositions, text, etc… applied and some shots which don’t match the pulldown cadence of the overall film will still have interlacing artifacts (horizontal streaks), but it’s a much simpler process.

Here’s how to remove pulldown:

1. If you are processing your source footage, launch Compressor and add it to the queue. If you are processing after export, export your edit from FCP using File > Export QuickTime Movie, use Current Settings and All Markers options and load the resulting file into Compressor.

2. Locate the ProRes 422 preset by typing “422″ in the settings list search box. Click the Duplicate (+) button. Clear the search box, and select the new preset to change its settings.

3. Rename the preset “Reverse Telecine.”

4. In the Inspector window, click on the third tab, Frame Controls. Click the gear to turn off Automatic mode. Turn Frame Controls on.

5. Set the deinterlace option to “Reverse Telcine.” Click Save.

6. Drag the new Reverse Telecine preset onto the clips in the batch window.

7. Set a destination from Target > Destination > Other… and specify a destination folder.

8. Click Submit, click Submit on the dialog which follows.

9. Open the resulting file and watch it to ensure the process worked. If something seems strange about the file (jumpy, stutters), Compressor couldn’t remove the extra frames. If the process worked (as it should most of the time) this is now your master.

If you are processing your original footage, quit FCP and append “-29” to the end of the file names of the original footage. Re-open your project, and when asked to relink the media, point it to the new files generated by Compressor.

BACKGROUND

Telecine machines are designed to capture film onto tape formats—and until recently, all tape formats were limited to 29.97 FPS, interlaced video. The Telecine machine uses a process called 3:2 pulldown to generate new frames in order to make the 24 FPS fit into 30 FPS. Modern video distribution systems including projection from hard disk (ie Film Finals), DVD and especially web are capable of displaying true 24P, and in fact, 3:2 pulldown will make the video quality look significantly worse than true 24P. This shows up as horizontal blur and a streaky artifact. Older software used to require a special file from the telecine machine in order to know how to reassemble a 24p file from 29.97i video, Compressor’s Reverse Telecine feature is new and great in that it can analyze and automatically locate/remove the extra frames that 3:2 pulldown adds.

NOTE ON THE DVX100 CAMERA

The Panasonic DVX100 shoots 24P onto 60i tape, and adds pulldown in order to do so. If you shot using the 24PA setting, there’s an option in Log & Capture in Final Cut called “Advanced Pulldown Removal” which you should use when capturing to convert the footage on the fly back down to 24P. If you didn’t do this during capture, you’ll need to use the Remove Advanced Pulldown option in the FCP tools menu, or use Cinema Tools to remove pulldown—compressor won’t be able to figure it out. If you shot using the standard 24P setting, then you can use compressor to remove pulldown.

NOTE ON HVX200, HPX170 AND HPX300 P2 CAMERAS

The HVX200 and can record 24 FPS directly without adding extra frames. This mode is called 24PN, for 24p native. It also has options for 24PA and 24P with 3:2 pulldown. Unfortunately, only the 720 resolution supports 24 PN, but the good news is that if you shoot 24PA, you can select the “remove duplicate frames” option in Log & Transfer, and FCP will do reverse telecine for you during capture. If you accidentally shot in 24P, you need to remove pulldown as mentioned above.

NOTE ON HDV 24P

If you shoot 24P on a HDV camera, you should check the “Remove extra frames” box in Log & Capture. Otherwise, you have to remove them as detailed above.

Most newer file based cameras (DSLRs for example) record directly to 24P and so you can forget all this nonsense.

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Comments
  1. Sage says:

    So aren’t you degrading the image if you shoot in 24 with your DSLR and then edit in FCP at 29.97? wouldn’t it have been better to shoot in 30 fps setting to begin with?

    • ctiptonk says:

      You are correct—but these instructions aren’t meant for that workflow. These instructions are intended for footage shot on cameras that shoot at 24 FPS but store the data at 30; and often beginning editors aren’t aware of the problem until they look at their sequence settings and discover they’re at 29.97 when they should be at 23.98, and the problem is that the pulldown wasn’t removed before editing.

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