Why does my Logitech Quickcam's audio cut out midway through a video recording?

I have a Logitech Quickcam webcam, and whenever recording a video, after about 20 seconds of recording the audio just turns into static. Replaying the video from the start and changing the audio feed settings doesn't seem to work, and Logitech's support site is very vague and unhelpful. Any answers would be much appreciated.