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Audio Sync problem
I’m having a problem with audio sync on a current project. It’s a 4 camera shoot, all recording audio at 48khz. No problem syncing them all up (video & audio). I also recorded a sound board mix directly into my laptop, also capturing at 48k. Every 5 min or so this sound board .wav file seems to go just a hair out of sync, then progressively more on the timeline compared to the video/cam audio tracks. I have to cut my project every 4 min or so to sync this separate audio file to the camera files.
Any Ideas what I could have done wrong during the shoot? Perhaps I’m not setting up Vegas properally for the edit?
RR
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1 Reply
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You didn’t do anything wrong. The crystal clocks in all digital devices are slightly off. It sounds like the one in your PC is off more than the cameras are. This is why you need genlock sync to do multicamera properly. I usually take a feed off the board like you but I use a Marantz PMD-660 field recorder and it’s good for about 15 to 20 minutes and then it drifts. You just have to keep cutting and resyncing.
PC’s have a habit of multi-tasking at the wrong time. It may be possible that some of the slow down is due to other processes on your computer periodically waking up and stealing some CPU cycles. You might want to consider a dedicated field recorder to keep things more in sync.
~jr
http://www.johnrofrano.com
http://www.vasst.com
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