Does anyone know where I can get Dumpster?
http://developer.apple.com/quicktime/download/
However the URL for Dumpster chucks out a 550 error. As far as I can tell from forum posts the link worked up to at least early 2009.
There is from what I can tell a third party application that does the same sort of thing called Atomic Dumpster but it only let's you view the structure and atoms of video files and not edit them.