title: Audio Metering with LibVLC
body: <p>I'm using LibVLC in a Windows C++ application to display a video stream. </p>
  
  <p>I want to monitor the incoming audio samples to generate metering data passed to another part of my application. I have this sort-of working with <code>libvlc_audio_set_callbacks</code> except a: I'm monitoring the output audio, so it's affected by mutes,etc and b: When I enable this, the audio can't be heard (admittedly, this is the behaviour described in the documentation).</p>
  
  <p>Is there a way of actually doing this with the LibVLC API, or do I need to write an audio filter plugin? </p>
  
  <p>Alternatively, Is there some existing generic 'audio sniffing' plugin that I could use?</p>