title: Record only caller's voice in android
body: <p>I am using <code>MediaRecorder</code> for recording call in android. But I only want to record the caller's voice. Can this be done?</p>
  
  <pre><code>    recorder.setAudioSource(MediaRecorder.AudioSource.VOICE_CALL);
      recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
      recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
      // mRecorder.setOutputFile("/sdcard/yousuck2.3gp");
      if (audiofile == null) {
          File sampleDir = Environment.getExternalStorageDirectory();
  
          try {
              audiofile = File.createTempFile("ibm", ".3gp", sampleDir);
          } catch (IOException e) {
              Log.e(TAG, "sdcard access error");
              return;
          }
      }
  </code></pre>
  
  <p>Also what is the difference between <code>VOICE_CALL</code>, <code>VOICE_UPLINK</code> and <code>VOICE_DOWNLINK</code>? I read the Android docs but could not understand.</p>