First and foremost -- I need to see a log file to know how you're capturing, what your setup is, and other details.
If you are capturing your PC via window/game/monitor capture, and the sound of your computer does not match the capture, you probably need to turn on the "Force desktop audio to sync to video timestamps" in advanced.
If it's a device such as a mic or capture device, that's a different story (and why I need a log file).
