If your animation is generated entirely within AE (no external movies or image sequences), you can simply drop your 30p comp into a 24p comp. Make sure that “Preserve frame rate” in the original comp’s Advanced settings is turned off. Double-check that any camera moves or quick animations are acceptable at the lower frame rate. Voila – now your animation is 24p.
If you do have external footage, you’ll want to use some sort of optical flow-based technology like the ones Dave mentioned; I’m a Twixtor fan, but you could also try AE’s pixel motion-based frame blending.
Don’t ignore Dave’s advice on double-checking the frame rate — 23.976 fps is often called 24p, but the difference is not negligible!
Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
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