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AUDIO/VIDEO SYNC PROBLEMS
[I also posted this in the regular “Apple Final Cut” forum on the Cow. If this counts as a “double post,” I apologize. Not knowing how much crossover there is between the two forums, I just wanted to get this in front of as many eyes as possible]
First, a little background: I’ve had a broadcast journalism degree for 15 years, and the first 14 of those years were spent in public radio. But recently, the communications department of the university where I work found itself stuck between a rock and a hard place: The need for somebody to produce VNRs about university research & extension programs… but without the necessary funds to hire somebody outright to do that. So I volunteered to transfer out of my “radio digs” and try a bit of video production.
Last year, I had a video workstation set up in my old office, on the other side of campus. A couple of weeks ago, that same system (details below) was dismantled and installed in my new office. Same Mac G5, same software (FCP HD), but there are a couple of differences…
1) I now have two widescreen monitors, instead of one
2) There’s a new video card in the system: an AJA Kona LS card. Previously, I was just using FireWire for import/export.
Since then, I’ve suffered recurring loss of sync on all my FCP timelines. This includes both old material (projects that were loaded within the past year, in my old office) and new video captured in just the past day or two. Sometimes, the video seems to be lagging several frames behind the audio; other times, it’s the opposite.
I’ll open up a project… fire up the timeline… hit the spacebar, and everythings out of whack. Tap the spacebar to stop playback, immediately tap the spacebar again… and now everything’s in sync. Step away from the system for a minute or two, come back, hit the spacebar… now we’re out of sync again. The machine truly seems to be deciding at random whether or not it’s going to play back the timeline in sync!
A couple of days ago, I opened up a timeline that I started just the previous day. I exported @ 60 seconds of the video to a self-contained QT movie. When I play the movie… video and audio is in perfect sync!
MY SYSTEM
Dual 2GHz PowerPC G5
3 GB DDR SDRAM
OS 10.4.6
ATTO ul4d SCSI card
2 Medea RTR drives stripped as a single RAID for local storageSTILL TO ADD:
Distribution amps, both audio and video
Right now, only component and SDI… composite will be available once the amps are installed.
That’s where we’re at right now. Thanks for your help! 🙂
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2 Replies
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Where are you seeing your sync issues? Are you previewing to an external video monitor, or simply from the Mac screen? Are you mixing video resolutions / codecs on the timeline?
There can sometimes be a sync delay in what you see on your Mac’s monitor if you have external video pumping out simultaneously…? Should be in sync on the video monitor though…
This delay will disappear if you playback a QT outside of FCP, because the machine isn’t outputting an external video as well.
I have also experienced erratic behaviour on my G5 if I happen to walk away long enough for my machine to go to sleep. Once it wakes up, it can go a bit loopy.
Enzo Tedeschi
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Editor
Sydney, Australia -
I have just experienced this problem in a major way on a big project after running Disk Warrior on the external firewire drive that the project was on. Audio has a mind of its own, sometimes plays left and not right, hit play again and right and not left, sometimes one track plays out of sync with the other, sometimes one plays slower than the other.
I tried a new test project with a file I knew to be OK from a separate hard drive and the problem persisted until I shut down, unplugged what I now assume to be the problematic firewire drive, restarted then test project worked, then when I mounted the fire wire drive again the problem returned intermittantly with the test project so I surmise that the issue is with the fire wire drive.
I am just copying everything to an internal sata drive which I hope will cure the problem. I will let you know.
If anyone else has any suggestions I would be really glad to hear them
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