title: Accessing the Android media stream for audio visualization
body: <p>Basically, I want to make an audio visualizer.  I know it's possible, because my phone came with a few live wallpapers that do it.  The problem is, I can't seem to figure out how to do this with the Android API.</p>
  
  <p>My app would pick up the currently playing media stream and then depending upon the volume that is playing at that time, it would display more or less bars on the screen.</p>
  
  <p>How can I do this?  It looks like I could do something like this using the microphone, but I want to be able to do it for music, podcasts, etc.</p>