title: How to get volume data from an input device in Core-Audio?
body: <p>I am trying to get the volume of the audio heard by an input device using Core-Audio.</p>
  
  <p>So far I have used <code>AudioDeviceAddIOProc</code> and <code>AudioDeviceStart</code> with my <code>AudioDeviceIOProc</code> function to get the input data in the form of an <code>AudioBufferList</code> containing <code>AudioBuffer</code>s.</p>
  
  <p>How do I get the volume of the data from the <code>AudioBuffer</code>? Or am I going about this completely the wrong way?</p>