Android AudioRecord class – process live mic audio quickly, set up callback function

After experimenting lots with the notifications and a bunch of other techniques I settled on this code:

private class AudioIn extends Thread { 
     private boolean stopped    = false;

     private AudioIn() { 

             start();
          }

     @Override
     public void run() { 
            android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);
            AudioRecord recorder = null;
            short[][]   buffers  = new short[256][160];
            int         ix       = 0;

            try { // ... initialise

                  int N = AudioRecord.getMinBufferSize(8000,AudioFormat.CHANNEL_IN_MONO,AudioFormat.ENCODING_PCM_16BIT);

                   recorder = new AudioRecord(AudioSource.MIC,
                                              8000,
                                              AudioFormat.CHANNEL_IN_MONO,
                                              AudioFormat.ENCODING_PCM_16BIT,
                                              N*10);

                   recorder.startRecording();

                   // ... loop

                   while(!stopped) { 
                      short[] buffer = buffers[ix++ % buffers.length];

                      N = recorder.read(buffer,0,buffer.length);
                      //process is what you will do with the data...not defined here
                      process(buffer);
                  }
             } catch(Throwable x) { 
               Log.w(TAG,"Error reading voice audio",x);
             } finally { 
               close();
             }
         }

      private void close() { 
          stopped = true;
        }

    }

So far it’s working pretty robustly on the half a dozen Android phones I’ve tried it on.