title: Android: AudioFlinger could not create record track, status: -1
body: <p>I developed an android-app (Home Noise Alert) and it works fine on many devices. But now I got an error report from a user who uses following device:</p>
  
  <pre><code>ANDROID_VERSION=6.0.1
  PHONE_MODEL=HTC One A9
  </code></pre>
  
  <p>A kind User send me an error report, but I don't understand it. He got this error if he started the app.</p>
  
  <p>This is the error log:</p>
  
  <pre><code>02-05 18:42:41.501 E/AudioRecord( 6200): AudioFlinger could not create record track, status: -1
  02-05 18:42:41.505 E/AudioRecord-JNI( 6200): Error creating AudioRecord instance: initialization check failed with status -1.
  02-05 18:42:41.505 E/android.media.AudioRecord( 6200): Error code -20 when initializing native AudioRecord object.
  02-05 18:42:41.505 E/android.media.AudioRecord( 6200): startRecording() called on an uninitialized AudioRecord.
  </code></pre>
  
  <p>I believe this bug occurs if a microphone is blocked by another app, do some body have any experience with such errors?</p>