You can get the size of the movie with the property naturalSize.
moviePlayer.naturalSize.height //to get the height of the frame player
UPDATE!!
Hope it helps
-(CGRect)getResizedVideoFrame:(CGRect )naturalSize andPlayerViewSize:(CGRect)playerSize {
float resVi = naturalSize.size.width / naturalSize.size.height;
float resPl = playerSize.size.width / playerSize.size.height;
return (resPl > resVi ? CGRectMake(0, 0, naturalSize.size.width * playerSize.size.height/naturalSize.size.height, playerSize.size.height) : CGRectMake(0, 0,playerSize.size.width, naturalSize.size.height * playerSize.size.width/naturalSize.size.width));
}