k, best lead for it I see is it's mentioned on this page:
http://www.degeelebosch.nl/corone/dsfp/main.htm
which points for it being a plugin for this:
http://en.wikipedia.org/wiki/DirectShow
I'm a mac guy, so when it comes to installing things on my PC I'm a bit weary since I'm guessing if I install Directshow it's gonna fuck something else up in WMP, and then my workstation is pretty much useless.
Oh well.. from what I can tell a decent FLV splitter does not exist.. period.. end of story.