Audio sync problems in FCP 3

[Thaxter Clavemarlton]

1. I’m betting your camcorder audio recording was preset to 32 kHz your FCP timeline is set to 48 kHz.
(Or your FCP timeline is 32 kHz and your tape is 48 kHz.)

2. “Sync-slippage” can happen during some longer captures, and has been more prevelent using fottage shot on Canon camcorders.

To avoid it, break your captures into sections no longer than about 10 minutes each.

You can then “reconstruct” the full tape’s recording (or any longer takes) quickly if you need to.
Mark (and log) your first clip to End (Out-point) about 10 minutes or less from its In-point.
Continue to mark (and log) your clips this way throughout the rest of the tape.
Just make sure the In-points of the subsequent clips are EXACTLY ONE FRAME LATER than the Out-points of the previous clips.

You can do all this while actually scanning the tape(s) or just by inputting arbitrary TC numbers, logging them… then use Batch Capture to bring in all of your clips.

Its very easy to then “reconstruct” the shorter clips back to any “continuous” length you want on the timeline by just “clicking” them on in order.
EVEN FASTER… select ALL successive clips at once in the browser (with the browser column-order set to “Media Start” highlight all clips) and drop them, all at once, on the timeline… they’ll all pop up in continuous order.

[Rob]

Hi and thanks for the response!
about the 32 vs 48 kHz – how do i change that in my timline/viewer – i know the camera records at 48 kHz

I guess logging them in 10 min intervals isn’t the end of the world – but it would be nice to work on other things for an hour if capture now worked – i guess life isn’t fair

I am using a canon GL 2 – but im surprised to hear that the camcorder is the problem.

thanks again

[Gunner Jones]

Rob,
Here’s the rule of thumb with digital video capturing.

The slower your drives and the longer the clip you are capturing, the more succeptible you are to receive dropped frames. Capture Now exacerbates this issue.

Try these things:

[Rob]

I there Gunner- i appreciate your advice i will try to use ins and outs and batch capture – and then break it into smaller chunks if that dosn’t work.

About maintaining your drives – how do i go about doing that with disk utility and what is disk warrior? – i a new mac user – i definatley don’t want to take any chances with my work. – all i have is the built in 80 G hardrive on my G4
thanks for the support – it helps big time

[Thaxter Clavemarlton]

[rob] “i know the camera records at 48 kHz”

The camera can record EITHER.

Its easy to have it set to 32kHz by mistake.
That would account for the FCP timeline “beeping” at you (it means the audio need to be rendered.)

[Rob]

Hi there and thanks for the post – does it make sense that my audio would beep in the viewer and not the timeline – thats the case
thanks

[Gunner Jones]

In Disk Utility, you can repair permissions. I do this once a week.
Disk Warrior rebuilds your directory, but you have to purchase that.

Neither of these tools will damage anything on your drives.

O&O-Gunner Productions
FCP-Avid-After Effects

[Mario Rodriguez]

I’m glad I read this.

That’s an excelent trick actually. Log in – out in 10 min pieces and then do a batch log. Never thought about such a simple workflow, I always used capture now feature.

By the way, Canon camcorders (don’t know if all Canon models or some) don’t use an exact 48Khz audio sample rate, but something like 47.997Khz or round that. That makes a second or more out of sync video audio per hour of capturing.

In FCP 4 that’s suppose to be corrected automatically but not sure if that works in everycase (maybe even better in FCP 4.5 HD), in FCP 3 you can set it to make a audio sync reset every 5 min or so. But didn’t work for me as far as I remember.

I also noticed than capturing directly to Offlline RT made things worst with audio sync issues. I guess because it is a more computer intensive task as capturing directly into DV.

That’s why I capture to DV and then recompress with media manager to offline RT. Why the way using this method I also get the DV Start/Stop detect in Offline RT which does not work if you capture directly to Offline RT…..

Mario

http://www.livemyadventure.com