looping the same video to compare different coordinates at various frames

[mgg]

hello,

    I am trying to analyze the x-coordinate of the first frame as compared to the second frame and calculate how much it has changed. I have attached a vi and tried to add in a second set of icons that do the same thing but starting start reading at i + 1; the problem is that since the file is already open it cannot run through two IMAQ AVI Read Frame, etc. I have deleted the second set, because it doesn't work, but have no ideas as to how to accomplish the comparison.  Any suggestions?

thanks,
mgg

[mgg]

nevermind. i figured it out.