The Platform SDK has a VB DirectShow example called builder that enumerates
DirectShow filters and allows you to connect them together. I can display an
MPG by adding the source file and the "video renderer" and telling the app
to "connect downstream", which will insert intermediate filters as

I'd like to display my Logitech Quickcam Express USB's video in the same
way. The filter list has the "Logitech Quickcam Express" filter (and a
number of other related filters), and when I add it and a "video renderer"
and tell the app to connect downstream, it adds an "AVI Decompressor" and
"Color Space Convertor". But when I tell it to run, it doesn't do anything.