Final Cut Pro - Can the video move pre subframe?

Question

I recently have two videos. And I want want to synchronize these two videos. But I found that the video can only be moved pre frame and the sound of these two video cannot match perfectly.  So I detach the audio of the 2nd video and I try to synchronize my "1st video" and "the audio of the 2nd video" first. My "1st video" and "the audio of the 2nd video" match perfectly because "the audio of the 2nd video" can be moved pre subframe. However, "the audio of the 2nd video" and the "2nd video" itself don't match perfectly because the audio can be moved pre subframe  but the video can only be moved pre frame.
How can synchronize everything perfectly?

Answer 1

When you shoot with two cameras, if you want perfect synchronicity,  you must lock the video at the time of the recording by using cameras that allow for "gen lock" which uses the sync from either an independent sync generator, or the video of one of the cameras as a reference to lock the cameras together.
More on Gen Lock here:
http://en.wikipedia.org/wiki/Genlock
Without an electronically locked signal, you have the result you are having.
Within FCP, the audio can be moved at the subframe level, but not the video, which must be moved at the frame interval. In most editorial situations, the subframe offset of the cameras does not pose a problem, since the slight temporal shift will be masked by the dramatic image shift of the edit anyway, but I could see where it would be a problem in scientific, effects, or compositing work.
MtD