Imagine your dismay when the movie file you just downloaded has audio sync problems. Non techie people will usually look for another version of the movie file and download it again while those adept in video encoding will re-encode the video and audio and merge them as one.
Before doing those two I mentioned, there is a quick fix in your VLC Player that is nowhere to be found in any of its menu. With either two keypress of the keyboard, you can either delay the audio or increase its milliseconds.
Press ‘F’ for audio delay and ‘G’ for audio increase. Play around with it until the audio gets in sync with the video. This should work in Windows and Mac OSX versions of the VLC player.