Audio out of sync with video in iMovie

[badlydrawnboy]

I'm recording a video of myself using the built-in iSight with a Macbook Pro (Early 2011) running OS X 10.8 and a Blue Yeti Stereo microphone.

The audio and video are out of sync even when playing back in iMovie (before export), but the issue gets worse after export.

I did some research and found this article, which suggests 1) ensuring the DV camera was set to 16-bit, 2) making sure I am running iMove 3.0.3 or later, and 3) separating the audio and video tracks.

I don't know how to check for #1 with an iSight camera; I am running iMovie 9.0.7; and I tried separating the audio and video tracks, but that didn't help.

What is causing this problem, and what can I do about it?

 

[filmedit22]

Hey badlydrawnboy,

I know this is a year late, but I was having this exact issue today and was banging my head against a wall trying to figure it out, and couldn't find any help online. I wanted to post my solution.

Previously I had made a project using the iSight camera, in iMovie (actually, using the Yeti mic too oddly enough), that was perfectly in sync. However, the project I was working on today wasn't in synch. I looked at the information in the actual video files created in iMovie and saw the file that didn't have issues was running at 30 fps, while the problematic file was at 16 fps. I decided the lower frame rate (16 fps), which was not matching my project settings, would most likely be causing the audio sync issues.

After researching, I discovered the iSight camera changes frame rate based the amount of light available during the recording. With plenty of light, it shoots at 30 fps. If there isn't enough light, one of the things it will do to compensate is lower the frame rate. While keeping the video bright, it causes issues keeping audio in sync in a timeline that is set at 30 fps.

Long story short - film near a window when the sun is out

Hope this helps!

 

[Partron22]

Not sure this applies to desktops/portables, but on tablets, out of sync sound is often fixed by rebooting the device. Poor memory management appears to be the underlying issue.