Sync problem

Hi!

I have a sync problem.

I've recorded sound with zoom h4n and video with gh4. Both is 48.000khz. When I try to sync the two in fcp7, the sound from the h4n is 9 frames ahead of the video sound, six minutes after the point where they are in sync. After 28 minutes they are 40 frames apart. It's drifting, in other words. I don't understand why.

I've tried to record both with cinematic 24p and pal 25p. It's the same. Since I wasn't sure if the 24p cinematic was really 24p or 23,98p I tried sequences with both settings. It didn't change much. Does anyone have a clue? Any help is much appreciated.

(another question – Not so important, but interesting. When I record 24p cinematic, the video file information says: "Field dominance: none". When I record PAL 25p, it says "Field dominance: upper". Does anyone know what the difference is? I thought field dominance should be "none" if the file was progressive and not interlaced, and 25p isn't interlaced, is it? p is for progressive, right?)

Best, Petter