title: VOICE_DOWNLINK doesn't work?
body: <p>I'm creating an application that records a phone call. I did use Android's <code>AudioSource.MIC</code>, <code>AudioSource.VOICE_COMMUNICATION</code>, <code>AudioSource.VOICE_CALL</code> and <code>AudioSource.VOICE_DOWNLINK</code> but all I hear is from the outgoing side.<br>
  And When i use <code>AudioSource.Voice_DOWNLINK</code>, like below occurs error.</p>
  
  <pre><code>02-26 16:23:44.292: E/MediaRecorder(9483): start failed: -2147483648
  02-26 16:23:44.293: W/System.err(9483): java.lang.RuntimeException: start failed.
  02-26 16:23:44.293: W/System.err(9483):     at android.media.MediaRecorder.start(Native Method)
  02-26 16:23:44.293: W/System.err(9483):     at com.mypackage.startRec(Recorder.java:29)
  02-26 16:23:44.293: W/System.err(9483):     at com.mypackage.onStartCommand(RunService.java:336)
  02-26 16:23:44.293: W/System.err(9483):     at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:3010)
  02-26 16:23:44.293: W/System.err(9483):     at android.app.ActivityThread.-wrap17(ActivityThread.java)
  02-26 16:23:44.294: W/System.err(9483):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1442)
  02-26 16:23:44.294: W/System.err(9483):     at android.os.Handler.dispatchMessage(Handler.java:102)
  02-26 16:23:44.294: W/System.err(9483):     at android.os.Looper.loop(Looper.java:148)
  02-26 16:23:44.294: W/System.err(9483):     at android.app.ActivityThread.main(ActivityThread.java:5417)
  02-26 16:23:44.294: W/System.err(9483):     at java.lang.reflect.Method.invoke(Native Method)
  02-26 16:23:44.294: W/System.err(9483):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
  02-26 16:23:44.294: W/System.err(9483):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
  </code></pre>
  
  <p>And below is MediaRecorder source.</p>
  
  <pre><code>public static void record(String path){
          mRecorder.setAudioSource(MediaRecorder.AudioSource.VOICE_DOWNLINK);
          mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
          mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
          mRecorder.setAudioSamplingRate(44100);
          mRecorder.setAudioChannels(1);
          mRecorder.setOutputFile(Path);
          try {
              mRecorder.prepare();
              mRecorder.start();
              mIsStart = true;
          } catch (Exception e) {
              stopRec();
              File file = new File(Path);
              file.delete();
              e.printStackTrace();
          }
      } else {
          mRecorder.stop();
          mRecorder.reset();
          mRecorder.release();
          mRecorder = null;
          mIsStart = false;
      }
  }
  </code></pre>
  
  <p>My test phone is Nexus5 and Android 6.0.1.</p>
  
  <p>Thank you for reviewing it.
  Thanks in advance for your answer.</p>