One alternative to pure-bitmap video is "vectorized" video. Vectorized video is a process where one takes traditional video and converts it to vector-based graphics. With this technique, the Flash designer now has the ability to incorporate extra-ordinarily fluid animations without overloading the movie's overall file size .
Our process utilizes standard multimedia tools, including Flash, to convert video imagery into 2D vectors. In a project for the " FeedRoom " (http://www.feedroom.com), we took 21 separate vector videos and combined them with traditional video, music, sound, and Flash effects to create a 30-second spot in less than 180k (half of which is audio).