A dropped frame is when the capturing process cannot handle either the digitizing or the transfer of the image stream so it has to skip one or more frames in order to catch up in the timing.
A time code break is when the timecode is messed up on the tape. Usually because someone stopped the recording and rewinding back/forth and started up outside the existing time-code. so it is reset to 0 again.
This is the reason why you should "stripe" or "black" tapes. It means putting a consistent timecode track all over the tape. So no matter how you mess around with the tape, whenever you press record, it always has a running timecode. It makes the editors work a LOT easier.
Last update: 08:35 PM Monday, January 1, 2007