Overview
Generally any audio problems experienced when playing back a capture file were created at the time of capture.
Possible Causes
Sound cards are notorious for being sensitive to machine load and simply dropping or corrupting chunks of audio data during capture. It is particularly bad on USB based microphones. This problem can be witnessed in any software application that is capturing audio; audio can become garbled and/or drifts out of synch with any video capture.Mixing large screen captures with high frame rates, webcam video capture with large format and high frame rates can cause these problems. Unfortunately the sound sub-system does not indicate to the application that it is losing audio samples so it is only apparent that there is a problem on playback of the file.
Possible Solutions
Here are some points that can help reduce the load on the computer and sub-systems;- USB webcams can highly load the computer when running at high frame rates and large frame area
- Do not use USB based microphones if possible, these are very susceptible especially if combined with USB webcams
- Reduce the size of the screen capture area and screen colour depth to improve performance
- Reduce frame rates for screen and webcam video
- Use the fastest possible computer for capture with USB 2.0 when using webcam
When you have a capture with corrupted audio use the Export Audio(wav) function to create a wave file from the capture. This length (time) and quality of the wav file will indicate if the problem happened at capture time.