60p to 24p conversion

[Steev Dinkins]

This thread is meant to report and discuss techniques for achieving 24fps from 60fps material from the GH1. You may have shot 720p60 for the stronger encoding and image quality, or because you wanted the option to do slow motion and speed ramping.

My question has been, how do you convert 60p to 24p. I've done a ton of testing on this. Here are the results.

These tests are using the HVX200 in 720p60 mode.

A) For reference, here's 24p native with 1/48th shutter speed:
http://www.holyzoo.com/content/dslr/...4p-720x405.mov

B) Now here's 60p shot with 1/30th shutter speed dropped into a 24p timeline in FCP (pretty unuseable):
http://www.holyzoo.com/content/dslr/...ty-720x405.mov

C) Here's 60p shot with 1/60th shutter speed - although its a little strobe like in its motion, I think it's useable for a 24p quick shutter look.
http://www.holyzoo.com/content/dslr/...ty-720x405.mov

D) To try to smooth out the stuttering I tried applying motion blur on clip C, using ReelSmart Motion Blur - RE:Vision Effects, Inc. : Products: ReelSmart Motion Blur

Here's the result:
http://www.holyzoo.com/content/dslr/...mb-720x405.mov

E) So now comes the twixtor test:
RE:Vision Effects, Inc. : Products: Twixtor

Dropped the 720p60 clip shot at 1/60th shutter, into a 59.94fps comp in After Effects. Dropped that comp into a 23.98fps comp and applied Twixtor to it.

http://www.holyzoo.com/content/dslr/...24-720x405.mov

For anyone who has done any 30p to 24p Twixtor'ing, I'm seeing a clear advantage to converting 60p to 24p vs converting 30p to 24p. There's twice as much information from which to do its thing.

F) 60p to 30p conformed to 24p. This results in slowing the speed down slightly, so you'd lose your audio sync, but the results are smooth. It's just like conforming 30p to 24p.

My workflow:

Drop 59.94fps clip into a 29.97fps timeline in FCP, then export that out, then conform that exported clip to 23.98fps with Cinema Tools. The footage will be slowed down slightly, but will be smooth.

Example - http://www.holyzoo.com/content/dslr/...4p-720x405.mov

Conclusion: Ultimately I think the Twixtor or the slow down method looks best. Although if I was cutting fast action, I think I could get away with the 1/60th 720p simply dropped into a 24p timeline.

-steev