If I’m writing an applet that shows a video sequence (eg. streaming from a camera, or the applet itself is running the on the camera), do my clients need to download the Java Media Framework libraries inorder to see the sequence?
Did you consider to use Java FX? This technology is dealing with this problem of downloading media libraries and so no. Of course. It is still in development. If to be first-adopter is option, it will be worth of considering this.