title: HLS -- add an audio track after the video playlist is created
body: <p>I have made an HLS playlist for a video file.<code>FeatureSDPlaylist.m3u8</code>. </p>
  
  <p>I now want to add in additional audio track to this playlist, for example as shown here: <a href="http://support.jwplayer.com/customer/portal/articles/1761348-multiple-audio-renditions" rel="nofollow">http://support.jwplayer.com/customer/portal/articles/1761348-multiple-audio-renditions</a>. I would prefer not to encode it all together, as oftentimes we receive a video file first -- at which point it should be encoded and available to play immediately -- but at a later time (perhaps in a month) there may be an additional audio track sent (for example, Spanish) that we want to enable.</p>
  
  <p>How would this be done?</p>