I'm starting my first project with FCP and need help. After capturing some tapes of a short movie I'm making, I found that the audio is slightly ahead of the video. When I watched the footage back on a TV from the camera, the audio was fine, so I'm guessing something went wrong with the capture. What would cause the lag between the audio and video, and how can I prevent it?

Here's some details: I shot with the DVX100A in 24P advanced and squeeze mode. I'm running FCP 5.0 on 10.4.2. I'm using a Canon ZR80 to capture through firewire. When I captured I used the DV NTSC 48kHz advanced pulldown removal setting. My plan was to capture the whole tape and organize it into subclips after, but due to time code breaks I ended up capturing in chucks around 30 min long.

Any help would be greatly appreciated.

Sorry, I can't offer specific help because I don't use your hardware and I have FCP 4.5. However, there's one thing you might check... depending on how you're monitoring the audio you may have a sync problem that doesn't really exist. The firewire output is not quite in sync with the output directly from your computer's audio port. So if you're viewing the footage on a monitor connected to your camcorder which has a firewire connection to your mac, the audio directly from the computer may not be in sync.

If this is the case, then you can either:

1. connect your monitor speakers to the camera as well so they're being fed from the firewire data as well

or

2. use digital cinema desktop to display the video on a second computer monitor and use the audio directly from the headphones/speaker port on your mac.

I think that's the problem. If I turn off the external monitor and watch the canvas, it looks like it's in sync. It's when I look in the monior that I notice a lag in the audio.

Thanks for your help.

You may find the answer here: http://www.adamwilt.com/24p/

Also, Canon cameras are notorious for not working well with FCP...many people find that the footage captured from a Canon camera lose sync.

Try capturing from your DVX and see what happens...

I think the problem is footage SHOT on a Canon, not captured by a Canon.

Some of the Canon cameras (i.e. XL1) have poor audio clocks so they record 48,009 samples of audio a second instead of 48,000. If you leave SAM --sync adjust movie-- off (it's something else in FCP5) then you will have sync issues. You may also need the firewire basic device control preset.

Possible problems:
A- Timecode breaks or other non-normal/ideal captures can cause problems. i.e. when copying from analog sources, some capture now scenarios
Sync will begin correctly but drift a lot.

Which version of Final Cut are you running?
FCP3 and below did not handle timecode breaks well. I suggest dubbing the tape so it'll get continuous timecode.
B- The DVX100 has a constant 1frame audio sync lag in 24p mode. See adam wilt's site
C- The footage is actually in sync, but there's a monitoring delay. (see Boyd's post)

When the problem first occurred I thought it could have been the DVX. (I was aware of the audio delay issue before I bought it) But when I watch the footage back on the TV, it's in sync. That's why I figured the problem had to have happened during capture. After reading Boyd's post I turned off my monitor and watched the footage in the canvas. It seems like it's in sync to me.

Normally I monitor audio through studio monitors plugged into an Mbox. My CRT monitor is connected to a DataVideo Dac-100 bidirectional converter, which connects to the computer through firewire. I never had a problem with this setup. But since I don't have the driver for Tiger, I can't use my Mbox right now, so I'm listening to the audio through the built in speaker in the G5. For some reason my Dac-100 is no longer being recognized by FCP 5, so I have to use the Canon to connect my monitor.

Once I get my system back to normal this week, I can really troubleshoot, because as Boyd said -- the problem might not really exist. If it does, then at least I know it has to do with how it was captured.

Thanks for all the replies.

Here's the current situation:

I got my Mbox and converter working and was still getting the sync issue. I tried capturing a 10 min clip from the DVX and it worked fine, so I know the problem isn't the DVX itself (I have the 100A which isn't supposed to have the bad audio problem). Next I captured three different clips with the Canon -- 5 min, 10 min, and 15 min. The only one that played perfectly in sync was the 5 min clip.

Since many people are telling me Canon's can give you sync problems when capturing, I tried a Sony DCR-HC21 camcorder. I captured three more clips and again, only the 5 min one played in sync. With the 10 min clip, two of the marks from the slate are synced up, and two aren't. It seems that, with the exception of the DVX (which I won't use for capturing), any clip over 5 min is slipping out of sync.

Any more suggestions?