title: Is there a Youtube API that gives only audio?
body: <p>I've searched for this question  several times</p>
  
  <p>Many suggested that 'Get both audio and video. And hide video.' and said that 'there is no audio only API'</p>
  
  <p>But it needs more traffic than when only audio is retrieved if I wanted to listen to music via Youtube.</p>
  
  <p>What makes me confused is, an android app called Firetube provides audio only.</p>
  
  <p>Is this just a trick or does Google provides AUDIO ONLY API?</p>