Audio sinc issues

[Camilo Ganado]

Im having some issues when linking sound, i have auidoreference from my clips, but when im trying to link it, it just get messy, couse i lost reference after a while, i guess is the drop frame, and i cant figure out how to change it.
We shot at 24 fps, the sequence is 1920x1080 HDTV 1080i (16:9) 24fps.
Any ideas?

BTW: Audio, video and the sequence is at 24 fps.

Thanks for the help.

 

[James Press]

Need more info Camilo...

Did you record audio dual system ie from a separate audio device?

And are you saying that at some point into your video (r3ds) clips, you lost audio entirely? But you have the audio from the separate recording, right?

If audio and video was all recorded at 24fps there should be no drifting, so you should only have to sync up once and it should carry through (unless there were dropped frames--were there?). Did you slate at the beginning of each clip?

 

[Camilo Ganado]

Thanks for the help.

Q1/ yes we record audio from a separete audio device but we send a reference to the camara, that audio is fine, and sinc.

Q2/ We didnt lose audio in the proxies or the .R3D, and we do have the audio from the separate recording.

Q3/ We do slate, in the beggining everything is fine, after about 2 min we lose some of sinc and about 5 min there is any sinc at all. I guess is beacuse some dropped frames, but i dont know were we get it o how we get it, any ideas? and how we can fix this?

Thanks

 

[joe hedge]

You recorded 23.98 sound and 24 picture or the other way around.

 

[ThomtheEditor]

try running an easy setup for your desired settings, then reimport your separate audio; oftentimes fcp needs to be reminded how to read the audio you're working with

 

[Cail Young]

You recorded 23.98 sound and 24 picture or the other way around.

You would think.

However, the truth is stranger.

FCP (at least, up to 6) does not like 24.00 BWF files from some recorders.

I can say for sure it likes the Cantar 24.00 stamp, but it does not like the PD6 24.00 stamp. Other units are up to others to test.

What happens is that even if you set everything to 24.00, jam sync everything, and use a TC slate FCP still tries to correct the speed of 24.00 BWF audio.

This is clearly wrong behaviour.

The fix is to use Sebsky Tools or another BWF converter to get the audio into 24.00 quicktime files which FCP does not mis-interpret and everything will line up fine.

In future, shoot at 23.98 or use a Cantar (or test sync beforehand!)