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Audio out of Sync
Hello All,
Alright, so I’ve been having an audio sync issue now for a couple of weeks. More specifically, I’ve been having an audio sync issue when I try to import something though an analog audio cable. I have a dual G5 with 3GB of ram, and I also have an AJA I/O attached to the until. Furthermore, I have a Xserve RAID system attached, which I load all my footage onto.
I’ve found that I can load digital things just fine – if I go in via SDI – AES/EBU I’m golden. However, if I go in Component – RCA/XLR I find myself losing sync. Also important to note, is that when it’s loading it looks/sounds fine. When I drop it into a track sheet is when I run into problems.
Fortunately I work in a post production office with several suits, so I am able to go to another suit and load my footage, but I would like to get my computer back up and running. This has only been a problem in the last month or so, and I’ve been racking my brain trying to find a solution. Has anyone else encountered anything like this? I’m not exactly sure if it’s the RAID, or the I/O, or the computer that is giving such a problem. Also to note, I’m running FCP 5.0.4….if that helps.
Thanks a lot!
Nate -
6 Replies
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Is the audio staring off in sync when you press play and then drifting out of sync as it plays, or is it out of sync a contant amount from the time you hit play?
Being that the I/O is firewire there is a latency issue with it. You need to set the frame offset (usually around 4 frames).
Are you monitoring the audio back out through the I/O or through the computer speakers?
Are you monitoring the video on the computer screen or a tv monitor? If so is that hooked up to the I/O? -
The audio starts off just fine, but then drifts out of sync. I’ve played a bit with the frame offset, but nothing seems to help. It is currently set to 4. I have tried monitoring it both through the I/O and through the computer speakers with the same result. To view it, I am watching a TV monitor that is hooked up to the I/O. So in theory, when I watch the monitor (being fed from the I/O) and listen to the audio (also being fed through the I/O) I should be all in sync – but I’m not.
Any ideas?
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[nateboston] “So in theory, when I watch the monitor (being fed from the I/O) and listen to the audio (also being fed through the I/O) I should be all in sync – but I’m not. “
Yes, that is the correct way to monitor. HHmm Interesting!
I guess the next question would be, what is the analog video source that you are digitizing from? -
The most recent is a VHS tape being played on a proffesional, but older, VHS deck. It has happend on other analog sources though – I had to load a DVCAM master via Component and XLR cables with the same issue. And actualy, that turned out even worse, because some of the audio would randomly cut out during the load. I also had this problem when I tried to load some old Hi8 tapes as well.
I’m begining to think that maybe my firmware on the I/O needs to be update? I’m not even sure if that is possible…
Or my do you think it could be FCP? When I loaded this stuff onto our other suit, which has FCP 5.1, it loaded fine. Granted, that suit has a different I/O setup though….
And my final concern is that it might be the RAID, which would not be good. However, I’ve cleaned up a lot of space on that, and I have run disk utility to clean it up – which worked beatifully and the drive was/is error free.
hmmm….
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[nateboston] “The most recent is a VHS tape being played on a proffesional, but older, VHS deck”
Ahhhh, my money would be on the fact that you probably need a TBC (time base corrector) I have seen this happen before when passing analog signals thru the I/O without a TBC, especially VHS.
You should check the other room and see what the different set up is with their I/O, compared to yours.
Also not a bad idea to make sure you have the latest firmware. Check the AJA site for that or call tech support. -
I think you might be onto something….in the other suit we do have a TBC…..thanks for your help! Much appreciated!
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