title: C++ audio mixing
body: <p>I want to be able to combine multiple tracks of audio into one file but have no idea what to do. I need to be able to do the following:</p>
  
  <ul>
  <li><p>I need to have multiple tracks playing simultaneously, and need to be alter the volume of each track at various points,</p></li>
  <li><p>I need some tracks to start at different time,</p></li>
  <li><p>And I need to be able to write the result to file.</p></li>
  </ul>
  
  <p>I'm not sure what library to use for this, if anyone has a suggestion that would be helpful.</p>