GH2 SlowMo Video Sync Question (Barry I'm looking at you!)

seanmcleod

seanmcleod

Well-known member
Hey guys,

I while back I was doing a music video in slow mo and Barry helped me out huge with a great chart on frame rates and the corresponding speed the music would have to be played at for sync... I did what the chart said and it worked out perfectly.

Now I'm prepping another video shooting on the GH2 (if it arrives in time) and I hope to shoot it at 1080/60i and do the slow mo thing again... I would like to do some tests to see what exact speed I want to slow the footage down to, so I don't know that info yet, but is there another similar chart which shows you if you slow the footage to 80% you speed the playback up such and such percent...

or is it just as simple as if you slow the footage 80% you speed the playback up 20% etc?
 
I don't know the exact ratio but I'd be startled out of my shorts if the GH2's 60i was anything other than 59.94. So you should be able to use the same HVX slowdown/speedup settings, since the GH2's 24p is 23.976 and its 60i is 59.94, just like the HVX is. Can't guarantee it as I haven't tried it, but yeah, run a test assuming the same numbers as from the HVX chart and I bet you'll find it works fine.
 
So to make sure I'm understanding... if I shot at 1080/60i, and plan on playing back at half speed, I should... ah I'm confused... I'm going to edit in 24p, so I will render out the 60i stuff to half speed... so does that mean the song should be speed up to 125%?

Sorry I need an example!
 
60i = 2.5x slow-motion when put on a 24p timeline and slowed down so that each field becomes a frame.

So if you want the song to play back in normal time, but all the action to be slow-mo, you'd have to speed up the song so that it only takes 40% as long to play it. So a 3-minute song (180 seconds) would be sped up so that it now plays in 72 seconds. Then you shoot it live in 60i with the singers sync'ing to the 72-second version. Then you import the footage onto a 24p timeline and set the footage to play back at 40% speed, and it should sync up perfectly with the regular-speed song.
 
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