Curious Lip-Sync Problems

[Sean Oneil]

I’d focus your attention at the IOHD. That sounds like where the problem may be coming from. Maybe call AJA support.

Sean

[David Roth weiss]

Tim,

You might try uninstalling the AJA drivers (using their supplied unistaller of course) and then reinstalling them. I suddenly developed asyncronous playback issues with my Kona card that were caused by some form of driver corruption, quickly and easily fixed by just ditching the bad ones. Also, make certain you have the latest drivers, AJA has released several new ones lately for most of their hardware products.

David Roth Weiss
Director/Editor
David Weiss Productions, Inc.
Los Angeles

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[Jeremy Garchow]

Turn off audio scrubbing (shift-s). Sounds weird, but try it and see how you like it.

Jeremy

[Tim Allison]

You don’t understand, Jeremy. These clips are being CAPTURED out of sync. This NOT a playback issue. We’ve experienced the “fast scrubbing causing the timeline to playback out-of-sync” issue, and this is NOT the same thing.

Some new information from yesterday….it is still an intermittent problem, but all clips that were captured out-of-sync were a consistent 7 frames off. The audio was ahead of the video. Every time this happened, we could throw away the media, batch capture again, the the second time through, the clips were captured correctly.

We changed the Firewire cable between the Io and the Mac…didn’t solve the problem.

[Jeremy Garchow]

Do you have a sync generator?

[Tim Allison]

Yes. We have one of those Horita BSG-50 black burst generators. The AJA tech support guy actually said to try disconnecting this from the Io-HD, and setting the Io to “free run” sync.

Our biggest problem is this is an intermittent problem. It is very difficult to test to track things down. Sometimes it does it, but most of the time it doesn’t. Even when it does ingest out-of-sync, if we just simply throw away the bad media, and then batch digitize to replace it, everything usually comes back into the system correctly.

If the thing would just consistently screw up, then we could actually test to see if the problem is with the Io, the Caldigit drives, Final Cut, or whatever.

Another problem is that this is a completely new system. We changed the Mac, the OS, the FCP version, and the input interface. About the only thing we didn’t change was the Caldigit drives, but we did change the eSATA host adapter card that it connects to. So we’re really just “shooting in the dark” trying to track down this problem.

[Richard Sanchez]

This posting is a year old, but somebody may still benefit from this so I’m posting my findings on this issue. I’ve noticed, that when I set my user preferences to “Make New Clip”, occasionally it will break up the clips with A/V 16 frames off sync. It’s consistently 16 frames each time. It’s also not a playback issue within FCP, since I checked the quicktime files. If I make the clip offline and recapture, it comes in fine and in sync.

The sync does not drift; it’s consistently 16 frames off. Also, it’s not due to full drives since I’m capturing to a near empty 5 TB, 5 way stripe and capturing DVCPRO HD. Not a very bandwidth-intensive codec. I haven’t found a pattern to it either, it seems fairly random.

The only suggestion I have, is if you’re using this method to capture your footage, make sure you double check the sync on each clip. Since recapturing a clip here and there, while annoying, isn’t a huge a deal, but giving your editor an out of sync clip is a big deal.

Richard Sanchez
North Hollywood, CA

“We are the facilitators of our own creative evolution.” – Bill Hicks