Need Help! Syncing sound from the AF100 to the GH2

C

Chadac

Member
I'm editing a project in Premiere that was shot on the AF100 and the GH2. The project was shot in 29.97fps on the AF100 and 23.97 over cranked 80% on the GH2 to get it to shoot 29.97.

The problem is that they aren't syncing. The project sequence has been set to a 29.97 frame rate and they play back perfectly, but when I try to sync the audio from the AF to the
slate on the GH2 it doesn't match. It looks like it might be drifting.

Do I need to do something to the GH2 footage to have it match?
 
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We were shooting a sitcom web show and the director wanted it to look like a TV sitcom. I had to over crank the GH2 because it doesn't shoot 29.97 in 1080p.

@ dtzfilms
I found that in Premiere Pro you can change the frame rate of the GH2 to an assumed frame rate to have it match.
Select the GH2 footage after it's imported - right click - select modify - interpret footage - assume this frame rate - type in 29.97
 
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I'm curious about your initial calculations:
23.976/29.97 is %80 exactly, but (and it's a big one) you need to run 23.976 at %125 to get 29.97 - even then I'm not sure these frame rates would hold up to sync based on jitter and clocking and all sorts of other variables. It doesn't mean they won't, I can't tell you how many times I've be surprised about the the stability of sync with the most random of devices. It also doesn't mean I'm right. I'm still finishing my first cup of coffee.

Were you slating at the end of each take as well? If not, that's something you can do on your next shoot. Were you feeding the both cameras mix of the production audio to make sync easier? Also something you can do on the next shoot.

In both cases you'd be able to tell if the drift was consistent and adjust. You could use the audio in a few scenes to simulate a slate at the end of a take (a particularly loud transient in both sets of footage) and see if the drift is consistent that way. Then adjust your calculations accordingly.
 
Petros Kolyvas said:
I'm curious about your initial calculations:
23.976/29.97 is %80 exactly, but (and it's a big one) you need to run 23.976 at %125 to get 29.97 - even then I'm not sure these frame rates would hold up to sync based on jitter and clocking and all sorts of other variables. It doesn't mean they won't, I can't tell you how many times I've be surprised about the the stability of sync with the most random of devices. It also doesn't mean I'm right. I'm still finishing my first cup of coffee.

Were you slating at the end of each take as well? If not, that's something you can do on your next shoot. Were you feeding the both cameras mix of the production audio to make sync easier? Also something you can do on the next shoot.

In both cases you'd be able to tell if the drift was consistent and adjust. You could use the audio in a few scenes to simulate a slate at the end of a take (a particularly loud transient in both sets of footage) and see if the drift is consistent that way. Then adjust your calculations accordingly.
Click to expand...


My first solution was to run the 23.976 at 125% to get 29.97 and it worked just fine. But then I found that I can have Premiere assume a frame rate for a specific clip. I changed the clips to 29.97 and now they stay in sync. You can now put the GH2 up there with your "random of devices" as another one that holds sync.

Thanks for your suggestions.
 
Chadac said:
My first solution was to run the 23.976 at 125% to get 29.97 and it worked just fine. But then I found that I can have Premiere assume a frame rate for a specific clip. I changed the clips to 29.97 and now they stay in sync. You can now put the GH2 up there with your "random of devices" as another one that holds sync.

Thanks for your suggestions.
Click to expand...

Hey, glad it worked out for you. I imagine it's a big relief and now you can get on with the good stuff! :) Enjoy it.
 
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