I have a MacBook with the internal webcam/microphone, and had been using it for video chat recently. In the last week or so, the people with whom I'm chatting can no longer hear me. The video is fine on both ends, and I can hear them, but they can't hear me. I've gone to System Preferences > Sound > Input. Internal Microphone is selected, and from testing it, it appears to be fine. I've tried both Skype and GMail chat, so I don't think it's a software issue. Any ideas on what the problem might be?