If a user scrubs my video, i want it to play from where they let it go...

So, every flash video playing component that I've used, does a standard progressive download. But I've seen some out there that when the user drags the bar to a later point in the video, it will start buffering from that point.

How is this done?

The ones I use, you can't even drag the playhead past the parts of the video that haven't been downloaded yet.

In other words, if I want to see the last ten seconds of a video, I would want someone to be able to drag the bar to that point and have the video start playing and buffering from there.

I'm a bit confused on this, and would appreciate some advice.

Thanks,

You can't scrub past the downloaded portion if the file is being progressively downloaded. To scrub to the end anytime during the download, the video needs to be from a streaming video server. That is, there is a special server side program that receives the data request from the scruber and starts to send data from that point, which is different from progressive downloading, which starts at the beginning and continues straight thru to the end.
EfV