I'm working on a flash player that needs to track how long a user plays a video for. In addition, I need to know the user. I can easily do that with a request to the server. What I've thought of so far is sending a request to the server when the user presses play and another when the player stops playing the video. The obvious problem with this approach is that the user can navigate away from the page with out pressing stop, before the video ends.
Are there know approaches you have tried/seen and would recommend?