web design how to prevent leeching. Flash anti leeching methods

I am desig开发者_开发问答ning a website with flash video content. If I pass in the URL to a .flv file as a flash parameter to the embedded video player someone can easily extract the URL and download the flv video file. How to do I prevent this? Can someone refer me to anti-leeching techniques being used my websites like youtube.

One technique I have seen is to keep "moving" the FLV files. Then in your HTML generation, supply the current key -- which is temporal (this may be a cookie, not just a physical path). This doesn't entirely prevent leaching if smart bots were deployed (and a normal human user can always get the raw FLV if they really want). However, anyone that tries to use an "old" key gets no data or a stub to a "no hotlinking, you jerk" FLV.