If you’re not worried about video/audio speed, you can can timestretch 80% the footage,(think timelapse cloud effects) or just simply reinterpret as 23.976 but both ways will be different speed/pitch.
If you need normal movement and audio pitch, it is a little harder but not impossible…
Apply timewarp, twixtor, magic bullet or nattress, and render out to 23.976 not 23.98 which is not precise enough for AE.
If you don’t want to buy any plugins, you can do it using AE’s built in timewarp that recreates frames to make 29fps to 23.976fps smooth as butter.
Timewarp requires the most work but comes with AE….
You will need Magnum’s automatic scene detect to break the scenes into separate layers so that you can use timewarp without edit point problems. You can use videocopilot.net’s Andrew Kramer’s frame rate converter https://library.creativecow.net/articles/kramer_andrew/fps.php
or just change the blend frames mode to timewarp mode or use my manual way…
What I use,
29.97p to 23.976 progressive
1.Put 29.97 video in new “start” comp
2. add effect->time->timewarp speed at 50%, filtering extreme,vector detail 20
3. make new “output” comp 59.94 fps and drop “start” comp inside it with timestretch 50%
4. output “output” comp with separate audio layer from original video at 23.976 fps fields off. add motion shutter blur if desired.
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