if the production allows it - pre-roll is a good idea as it can take a few frames for the timecoded device to 'lock on'

its also good practice to preload movie files in Catalyst to ensure they playback with no delay. just load the file into the layer the cue before, either in Inframe mode or one of the 'trigger >0" modes. then bring up the intensity to start the movie.

Nev.