many multiple passwords on many multiple files

individual paid for video streaming

[phazei]

I'm working on making a tutoring site. We want to be able to sell videos on it like 'basic algebra' or 'proper grammer' and the sorts.
Rather than subscription access giving everyone access to files after they've logged in, the user will be logged in and purchase whichever videos they want, then when they go to them, they'll just stream from the server.

I have setup the users database so if they purchase a video, it will add the video id to their info.

I'm not quite sure how to setup the videos themselves though. When they click the link to the video is needs to check if it's ID is in their info, if not it should take them to a purchase page, otherwise it should stream the video.

If they get to the video page I don't want them to be able to save the direct link to the video and send it to a friend either. It should check if they are not only allowed in the membership area, but have also purchased the video. So one member couldn't send the link to the other member since membership is free.

I'd also like some type of protection on the file itself, maybe an encryption key type thing. I'm guessing something that is sent to the file in the background that the user doesn't see that allows it to play, so if they save it it won't get the key so won't play.

I know that's a lot of question there, but if someone could just point me in the right direction or with a link with info on this it would be great.

Thanks,
Adam

Thought: Couldn't I use ht access file to redirect for ex
[site.com...]
Where 1234 the video id and not a folder and that could send it to a php script? And somehow I could generate a special link that wasn't directly to the file itself but still played it, like [site.com...] but the link to the avi file itself would need the $SESSID in it as well, and I'm not sure how to do that... sigh...

[phazei]

Hmm, I was looking into flash a bit more.
If I can password protect everything in a certain subdirectory uniquely using htaccess, as long as I can restrict access to the page I can restrict access to the file I think...

If I have a swf player and it streams a flv file, since the direct link to the flv file is inside the swf file, how safe is the file? And can I restrict access to it to the swf file only?