Converting 24fps film to 29.97fps video via 3:2 frame repeating pattern for NTSC broadcast. Must be reversed in post — essential technical step.
Anyone who needs to output 24fps material for NTSC broadcast cannot avoid pulldown. This process distributes 24 film frames across 30 video frames (more precisely, 29.97fps) – following a strict pattern: Frame 1 is used three times, Frame 2 twice, Frame 3 three times, Frame 4 twice. This 3:2 rhythm repeats endlessly. The result: your 24fps material fits cleanly into an NTSC timeline without stuttering or causing time dilation.
The practical pitfall is deeper than many realize. You might not notice anything on the first export – the pulldown information is in the pulldown flags of the file, not in the actual pixels. But as soon as you need to work backward later, for example, during editing in DaVinci or for color correction, you need inverse pulldown (also known as telecine removal) to get back to true 24fps. If you input the signal incorrectly, you'll get judder, flicker, or asynchronous audio. I saw it on a broadcast project where the colorist ignored the pulldown information, and suddenly all motion graphics were jittering.
On set, this usually doesn't concern you – your camera runs at 24fps, period. It becomes problematic in post-production: whether you need to deliver a DCP (24fps) or a broadcast master (29.97fps with pulldown) is decided by your distributor. Some NLE systems handle pulldown automatically, others don't. Avid long had a reputation for handling this more cleanly than Premiere. Final Cut Pro X handles it partially transparently – too transparently, because you don't always notice that pulldown is active.
A practical tip: Always save your offline material in true 24fps. Apply pulldown only on the final master export. And if you're shooting with RED, ARRI, or other cinema cameras: ensure your proxy workflow preserves the frame rate, otherwise, you'll need new proxies later for the broadcast version – an expensive mistake. Pulldown is a bridging technology from the analog era; with modern 4K and IP delivery, it's becoming less relevant, but in classic broadcast, it's still firmly embedded in the workflow.