title: capturing a video using camera2 and MediaRecorder
body: <p>i try to record a video with 2 different resolutions at once.
  Sometimes all goes well and sometimes the app seems to get stuck in of of the stop() methods of the 2 MediaRecorders. Can someone plz look through my code, wheter i'm doing something wrong?</p>
  
  <pre><code>package com.example.android.videorecording;
  
  import android.app.Activity;
  import android.app.AlertDialog;
  import android.content.Intent;
  
  import android.hardware.camera2.params.StreamConfigurationMap;
  import android.media.MediaCodec;
  import android.media.MediaRecorder;
  import android.os.Bundle;
  import android.hardware.camera2.*;
  import android.os.Environment;
  import android.util.Size;
  import android.view.Surface;
  import android.view.View;
  import android.widget.Button;
  
  import java.io.File;
  import java.util.ArrayList;
  import java.util.List;
  
  
  public class MainActivity extends Activity {
      CameraDevice mCamera;
      MediaRecorder mMediaRecorderLow = new MediaRecorder();
      MediaRecorder mMediaRecorderHigh = new MediaRecorder();
      CaptureRequest mCaptureRequest;
      CameraCaptureSession mSession;
      boolean recording = false;
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
          CameraManager manager = (CameraManager) getSystemService(CAMERA_SERVICE);
  
  
  
          File dir = new File(Environment.getExternalStorageDirectory().getAbsolutePath()
                  , "Test");
          if(!dir.exists()) {
              boolean s = dir.mkdirs();
              if(!s) {
                  AlertDialog.Builder alert = new AlertDialog.Builder(this);
                  alert.setMessage("could not create dir");
                  alert.show();
              }
          }
          final File outputFileLow = new File(dir.getAbsolutePath(), "testLow.mp4");
          final File outputFileHigh = new File(dir.getAbsolutePath(), "testHigh.mp4");
  
  
          try {
              outputFileLow.createNewFile();
              String[] cameras = manager.getCameraIdList();
              CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameras[0]);
              StreamConfigurationMap configs = characteristics.get(
                      CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
              Size[] sizes = configs.getOutputSizes(MediaCodec.class);
              final Size sizeLow = sizes[5];
              final Size sizeHigh = sizes[0];
              manager.openCamera(cameras[0], new CameraDevice.StateCallback() {
                  @Override
                  public void onOpened(CameraDevice camera) {
                      mCamera = camera;
  
  
                      mMediaRecorderLow.setVideoSource(MediaRecorder.VideoSource.SURFACE);
                      mMediaRecorderLow.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
                      mMediaRecorderLow.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);
                      mMediaRecorderLow.setVideoSize(sizeLow.getWidth(), sizeLow.getHeight());
                      mMediaRecorderLow.setMaxFileSize(0);
                      mMediaRecorderLow.setOrientationHint(0);
  
                      mMediaRecorderHigh.setVideoSource(MediaRecorder.VideoSource.SURFACE);
                      mMediaRecorderHigh.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
                      mMediaRecorderHigh.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);
                      mMediaRecorderHigh.setVideoSize(sizeHigh.getWidth(), sizeHigh.getHeight());
                      mMediaRecorderHigh.setMaxFileSize(0);
                      mMediaRecorderLow.setOrientationHint(0);
  
  
  
                      try {
                          mMediaRecorderLow.setOutputFile(outputFileLow.getAbsolutePath());
                          mMediaRecorderHigh.setOutputFile(outputFileHigh.getAbsolutePath());
                          mMediaRecorderLow.prepare();
                          mMediaRecorderHigh.prepare();
                          List&lt;Surface&gt; list = new ArrayList&lt;&gt;();
                          list.add(mMediaRecorderLow.getSurface());
                          list.add(mMediaRecorderHigh.getSurface());
                          final CaptureRequest.Builder captureRequest = mCamera.createCaptureRequest(CameraDevice.TEMPLATE_RECORD);
                          captureRequest.addTarget(mMediaRecorderLow.getSurface());
                          captureRequest.addTarget(mMediaRecorderHigh.getSurface());
                          mCaptureRequest = captureRequest.build();
                          mCamera.createCaptureSession(list, new CameraCaptureSession.StateCallback() {
                              @Override
                              public void onConfigured(CameraCaptureSession session) {
                                  mSession = session;
                              }
  
                              @Override
                              public void onConfigureFailed(CameraCaptureSession session) {
                                  mSession = session;
                              }
                          }, null);
                      } catch (Exception e) {
                          e.printStackTrace();
                      }
                  }
  
                  @Override
                  public void onDisconnected(CameraDevice camera) {
  
                  }
  
                  @Override
                  public void onError(CameraDevice camera, int error) {
  
                  }
              }, null);
  
          } catch (Exception e) {
              e.printStackTrace();
          }
  
  
      }
  
      /**
       * is called by button, should start/stop recording
       * @param v
       */
      public void trigger(View v) {
  
  
                  ((Button)findViewById(R.id.button)).setText("stop");      try {
              if(!recording) {
                  mMediaRecorderLow.start();
                  mMediaRecorderHigh.start();
                  mSession.setRepeatingRequest(mCaptureRequest,
                          new CameraCaptureSession.CaptureCallback() {
                              @Override
                              public void onCaptureStarted(CameraCaptureSession session, CaptureRequest request, long timestamp, long frameNumber) {
                                  super.onCaptureStarted(session, request, timestamp, frameNumber);
                              }
  
                              @Override
                              public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request, TotalCaptureResult result) {
                                  super.onCaptureCompleted(session, request, result);
                              }
                          }, null);
  
                  ((Button)findViewById(R.id.button)).setText("stop");
                  recording = true;
              } else {
                  ((Button)findViewById(R.id.button)).setText("start");
                  recording = false;
                  mSession.stopRepeating();
                  mMediaRecorderHigh.stop();
                  mMediaRecorderLow.stop();
              }
          } catch (CameraAccessException e) {
              e.printStackTrace();
          }
      }
  
  }
  </code></pre>