Where to Learn More
The ways in which alpha video can be used in your Flash projects are almost endless. You can dynamically change the background of a video, integrate video into traditional animation and games, or overlay a video-based interactive guide over your other Flash content with no loss of quality. However, keep in mind that the use of video requires a lot of bandwidth on the part of your audience, so evaluate your target market before including video in your commercial projects.
This article covers just the bare basics of this deep topic. Keying video over more traditional Flash content is becoming a very popular technique, so there is quite a bit of information now available on the techniques involved. For starters, check out the following resources: