Thats great, but just fire up a program like Audacity, set the input to "Stereo Mix" or "Wave Out" depending on your machine, press record then press play.
Now, with video it is harder since wmp and the like can write directly to video memory, but most of the binary stream formats for video have been reversed. I point you to the MMS devouring SDP among others.
My point here is if it is played back on your local machine, then the content can be captured. The best you can do is encrypt it. For audio, there isn't even much point to that. You just inconvienience (sp?) the pirate
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I only say it because the general Internet user is not savy enough to know about the recording aspect so it's just another "short-term" stop gap measure.
I always paraphrase the Las Vegas commercial: "Whatever is placed on the Internet, stays on the Internet." In other words, once you place something for others to see/hear/watch, it will never go away. There is always a cache version in the search engines or on the wayback archive. And there are always ways to copy or record what's out there. But it's the same in the physical world also. If somebody wants something bad enough, they'll get it.