Well tv programs in the us-NTSC use DF(drop frame) timecode. Which means every minute there are two frame counts dropped. Not actuall frames but just the counter. Except for every ten minutes. Just do some math and you'll find that a thiry minute show for tv isn't actually thirty minutes. Someone else will chime in for a more thourough X sooon. Anyways, I can't esplain too much right now as I have tri-tip about to burn YIKES!!!