Virtualdub is a free video editing program, which is officially described as a 'video capture/processing utility'.
While it may not have all the 'bells and whistles' of commercial video editing programs, it can process AviSynth scripts - and it works well with .AVI files - so it's ideal for this project...
There is no need to actually install Virtualdub - it's a 'portable' application - so you simply click on the appropriate file header to open it from the downloaded folder location.
Create a new folder called 'Virtualdub', and download the latest stable version of Virtualdub, by RIGHT clicking on the box below and 'save link as' or 'save target as' (depending on your browser)....Save the .zip file in your new 'Virtualdub' folder....
Unzip the files in your Virtualdub folder -
RIGHT click and select 'extract all' - (Untick the 'show extracted files when complete' box).
DOUBLE LEFT click to open the unzipped folder, and locate the file named 'Virtualdub.exe' - (it has a gear wheel and film strip icon)
RIGHT click on that file header and select 'send to - Desktop(create shortcut)'...
(Important: do NOT select either of the other 2 'gear wheel' icon files - that is 'vdub.exe' or 'auxsetup.exe')
The first time you select this new shortcut, accept the security warning - and remember to untick the repeat warning box.. The Virtualdub editing window will now open.
You have now set up the path to your Virtualdub folder, which you can now open by simply clicking on the desktop shortcut icon at any time.
The next step is to set up the video conversion applications.... Just click on the 'Converting the Video' heading below - or at the top of the page.