Apple Logic Express 7 - Manual (Page 463)

Chapter 19 Video 463
Synchronization Methods
The Continguous Sync option allows you to switch between the following sync
methods:
When Continguous Sync is turned on, Logic controls the playback speed of the movie,
keeping music and pictures in sync at all times. If the film has a soundtrack, the audio
signal will be transposed slightly, if necessary, by means of sample rate conversion. This
sync method is possibly more precise, but requires greater processing power.
Video to song adjust
Found under Preferences > Video, this global setting can be used to fine tune the
starting point of a movie.