I see on YouTube and others, as well as when I play an FLV locally, that I can scrub back and forth with the scrub bar, and as the playhead moves the frames of the video under the playhead's location are displayed. I suppose these are the keyframes. Is this purely a function available to progressive download only, and not streaming? I see players like the JW and Flowplayer that do not do this, but others like YouTube and Vimeo as well as the standard FLVPlayback component do. Does anyone know how to accomplish this functionality?