when you click save as avi , under the file name save it under a different name, like mine, I saved my original avi as Mizar. then when I ran it thru V.D. I named it MizarA. for some reason mine doesnt like to save the avi ( when I run it thru V.D.) under the original name so I add an "A" ( or whatever you want). when it starts running thru virtual dub you will get a screen showing its running and when its complete it will return to the original video you started with. Thats it. nothing to it. its ready to run thru Registax.