Flash is not just a web application tool or a vector animation application; it is also a media-creation tool. Even though it is possible to import video and sound into Flash and then use it, that process creates large file sizes in most instances. This is where streaming comes in.
Streaming is the capability to load a file, and as soon as it begins loading, it can begin playing. This process requires a streaming server (such as the Flash Communication Server), but you can still test everything locally or on a nonstreaming server. If you are testing locally, you will notice very little difference because using progressive download, the video will begin playing shortly after loading begins.
So what does this mean? It means that anyone can take nearly any video they create, and with a few clicks of a button, have it streaming on the web.
A great benefit of streaming technology is the capability to keep the video outside the main file, thereby making the main file size that much smaller.
But before you can stream video, you need to know how to manually create video in the format Flash will be able to stream.