title: Pocketsphinx returns empty string for hypothesis
body: <p>I'm using pocketshpinx for speech recognition in a custom C++ application. I noticed that sometimes the hypothesis string returned by the <code>ps_get_hyp()</code> method is an empty string. </p>
  
  <p><strong>Question:</strong> Is this an expected behaviour? If so, is there a way to tell pocketsphinx to not give the empty string as a hypothesis? </p>
  
  <p>Following is a snippet of the relevant portion of my code:</p>
  
  <pre><code>do { ReadAudioBuffer(); } while (!in_speech);
  while (in_speech) { ReadAudioBuffer(); }
  
  ps_end_utt(ps);
  hyp = ps_get_hyp(ps, NULL);
  </code></pre>
  
  <p>The <code>ReadAudioBuffer()</code> method:</p>
  
  <pre><code>void SpeechRecognizer::ReadAudioBuffer()
  {
      if ((k = ad_read(ad, adbuf, 2048)) &lt; 0)
      {
          UE_LOG(LogTemp, Warning, TEXT("Failed to read audio\n"));
          return;
      }
  
      ps_process_raw(ps, adbuf, k, FALSE, FALSE);
      in_speech = ps_get_in_speech(ps);
      FPlatformProcess::Sleep(0.005);
  }
  </code></pre>