It's possible, but probably not adviseable as a general rule.
In order to do it you'll need run the video with DTS (Direct
to Screen) turned OFF. This will render the video as a layer in
Director, but with a significant performance penalty due to the
fact that it cannot use hardware accelleration. So you'll need a
very fast computer to acheive reasonable results. Result will also
vary depending on how you encode the video.
So unless you have a one-off project such as an installaion
or presentation where you have complete control over the playback
machine (preferrably you have it as an authoring or test machine),
it's probably not a viable option.