Audio Out of Sync After Capture

I did a straightforward log and capture (from a VX2100) today and something weird has happened. In the L&C window I checked the (audio) preview box so I could monitor audio during capture (this was interview footage). No problem when I was capturing...all was as normal in the capture window.

BUT...(after capture and the footage was in FCP)...when I played the captured footage in the viewer or dumped it into the timeline there is a 14 frame lag between audio and video. Very Weird. If I slide the audio track 14 frames to the right the sound is synced but I get the little out of sync warnings in the timeline.

HOWEVER...if I capture the footage without checking the Preview box and bring it in...it is fine. no Sync problems. But, sometimes I do need to monitor the audio so this is a real pain.

I trashed prefs but to no avail. Tried a different tape. Same lag happens.

It was recommended in the Apple Groups that I just leave the preview box unchecked and monitor audio through the camera but that seems a cheesy jury rig...I should be able to monitor without that kind or workaround. Plus the speaker on the camera stinks (headphones...yeh, sure but come on...)

Anybody have any ideas? This is baffling. and frankly kind of a PITA.

Thanks

The Preview option does put stress on the capture process. Always turn it off while capturing. Check the audio while logging, turn off that option before capture.

> It was recommended in the Apple Groups that I just leave the preview box unchecked and
> monitor audio through the camera but that seems a cheesy jury rig...

Not at all. Everybody has to do the same thing. Professional setups should a) not be needing to use a camera to capture with in the first place, and b) should have a multi-channel mixer so that the computer and the deck can go through the sound system and you wouldn't have to use the Preview option.

But just for the sake of exploration, let's check something else. Are you using Capture Now or Log and Capture? If it's the former, how close to the beginning of the tape are you starting the capture? It's possible that the lag is a coincidence and you happened to hit a bad part of the tape when Preview is on, but didn't hit that same part when Preview was off. Long shot, but worthy of exploration.


www.derekmok.com

Hey Derek...

Thanks for the input...

I wish I didn't have to capture through the camera...care to help with my revenue and cash flow so I can invest in more equipment? That sarcastic response aside I am using the capture now mode. I had just a couple of soundbites I needed so there was no real need to go to L&C.

This was the first time in a long while I had preview checked. Mostly I log by visual...sync sound being incidental.

I checked the tape...it is fine. I am capturing from about 10 minutes into the tape and capturing 10 second heads and tails before and after the sequence I want.

> I checked the tape...it is fine.

How did you check it? DV data corruption can be impossible to spot either by visual or audio. One of the pains of digital.

Capture Now is inconsistent, so it won't help you nail down whether Preview is causing the offset. If you're interested in testing, try logging a chunk of video around the same spot where you had the problem. Duplicate the logged entry as another master clip and name them "Test Clip 01 Preview" and "Test Clip 02 No Preview". Now use Batch Capture -- capture Clip 01 with Preview checked, and Clip 02 with Preview unchecked. If you get the same results as you did before, then it's about as certain as can be that Preview must be unchecked when you capture. The option doesn't always cause the problems you mention, but it's still advisable to turn it off for capturing.


www.derekmok.com

When capturing with the DV cable sometimes the audio will go out
of synch (even with deck control and log and capture).
However by taking the output of the DV deck as composite (or even YC)
hooking up deck control and using one of the kona io settings
(8 bit ucompressed to DV)- I have never had my deck controlled footage
go uot of synch...
just as an FYI


derekmok Wrote:
-------------------------------------------------------
> > I checked the tape...it is fine.
>
> How did you check it? DV data corruption can be
> impossible to spot either by visual or audio. One
> of the pains of digital.
>
> Capture Now is inconsistent, so it won't help you
> nail down whether Preview is causing the offset.
> If you're interested in testing, try logging a
> chunk of video around the same spot where you had
> the problem. Duplicate the logged entry as
> another master clip and name them "Test Clip 01
> Preview" and "Test Clip 02 No Preview". Now use
> Batch Capture -- capture Clip 01 with Preview
> checked, and Clip 02 with Preview unchecked. If
> you get the same results as you did before, then
> it's about as certain as can be that Preview must
> be unchecked when you capture. The option doesn't
> always cause the problems you mention, but it's
> still advisable to turn it off for capturing.