A long while back we produced a MovingWindow program for this kind of task. We don't support it anymore, mainly because it's been so long since we developed it (2005?). *But* we do now make it freely available to anyone with a current DirectRT license. So feel free to try it out, here are the links you'll need. You will also need a code, but it will explain that when you try to run it.

MovingWindow:
www.empirisoft.com\Download\movingwindow\movingwin dow2.exe
www.empirisoft.com\Download\movingwindow\readme.pd f
www.empirisoft.com\Download\movingwindow\license.p df

Let me know if you have any trouble,
Blair