title: Can't play audio in android using MediaPalyer
body: <p>I have file location in <code>05-11 22:43:41.793: D/Play audio(9996): /storage/emulated/0/QRSpeech/sounds/Introduction_to_Android_1.3gpp</code></p>
  
  <p>I want to play this file using <code>MediaPlayer</code> like the code below : </p>
  
  <pre><code>mediaPlayer.setDataSource(tempDestFile); 
  mediaPlayer.prepare();
  mediaPlayer.start();
  </code></pre>
  
  <p>where the <code>tempDestFile</code> is file path as printed above.</p>
  
  <p>No sound is heard ? why ?</p>