Topic: Basic Audio Technology
Because video isn’t a perfect 30 frames per second, but rather 29.97*, syncing audio with a film transfer gets a little more complicated. Now you’ve got a video version of the film which is ALMOST real-time, but not quite. The difference isn’t noticable by watching the picture only, but it presents a problem when trying to syncronize the sound track to the picture. If you don’t slow down the sound accordingly, you will notice that the sound seems to drift away from the picture after 30 seconds or so. The difference in the rates is exactly the same as the difference between DROP FRAME and NON DROP FRAME video time code (0.03 frames per second). The drift would add-up to 18 frames every ten minutes.