Whoa! Audio synch going south!

[rbtjonas]

4/1/09
Hi, Strange occurrence that brings up two questions. I captured video of a coffee house concert. Widescreen anamorphic pulldown capture and sequence presets all synched. Timeline in 23.98.
I did a complete, all at once log-and-capture of my mini-dv tape that came through to the Browser, for some reason, as five clips of duration (approx.) 3, 6,8,23 and 52 minutes each. The video and audio of four clips are syncronized fine, but in the 23 minute clip the audio begins perfectly matched to the video and then gradually, the video moves ahead of the audio by five or more seconds. This is true both in the Viewer and in the Timeline.
Question #1: Why do log-and-capture operations often result in clips (in the Browser) that do not seem to parallel the start-and-stop operations of the camera when taking the footage?
Question #2: Most importantly! Why would one clip go gradually out of synch? And, how can I fix it? I suspect that I can recapture that portion of the original mini-dv, but is there a way to fix it in fcp?

thanks!

[andythefilmer]

well... you can try to separate the audio and video and then move the audio clip in the timeline about 5 sec back for that part. for the parts where it's gradually getting out of sync, you might have to go to some cutaways and then go back with the audio and video separated. i did that a while ago with my old VX2000. the audio and video were about 3 sec apart, but i accidentaly put that setting in Premiere but it worked fine when i separated them and moved the audio track.

[DPStewart]

Hey,

The auto-capture functions are good helpers, but they don't work perfectly all the time.
I suspect your out-of-sync portion can be fixed by capturing it again - but starting from just INSIDE the video portion you are trying to get.

Try this first.

Starting and stopping the record process can, at times, upset the various timing codes in the data. Capturing JUST that portion usually corrects for this.

Please report back with your findings.

EDIT: I suspect the audio timing error cannot be fixed easily in post. Easily that is.
The behavior sounds like possibly a there is a frame rate change somewhere in the stream. Accidental of course...

[rbtjonas]

Hi DP Stewart, Thanks. Yes, I'll try recapturing. I keep my mini-dv's offsite, so I'll retrieve the tape in a couple of days, recapture, and report back.