Trying to record videos using the built-in camera in my 27" iMac (mid-2011, fully updated Mountain Lion) up until recently got me video that had out-of-sync audio. Once I switched from 32- to 16-bit audio, the audio then came in sync on my end, but uploading it to Facebook (or Vimeo or YouTube for that matter) ends up with the audio once again being out of sync by a second or so.
What exactly is causing this, and how can I fix it?