Taking picture while recording video on Android

I have written the Android service shown below for recording the front cam in the background. This works very well. But now I would like to also take a picture every 5 seconds while recording. Is this somehow possible? When I try to open a second camera (in another service) I'm getting an error.

public class RecorderService extends Service implements SurfaceHolder.Callback {

    private WindowManager windowManager;
    private SurfaceView surfaceView;
    private Camera camera = null;
    private MediaRecorder mediaRecorder = null;

    @Override
    public void onCreate() {
        // Create new SurfaceView, set its size to 1x1, move it to the top left corner and set this service as a callback
        windowManager = (WindowManager) this.getSystemService(Context.WINDOW_SERVICE);
        surfaceView = new SurfaceView(this);
        WindowManager.LayoutParams layoutParams = new WindowManager.LayoutParams(
                1, 1,
                WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY,
                WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH,
                PixelFormat.TRANSLUCENT
        );
        layoutParams.gravity = Gravity.LEFT | Gravity.TOP;
        windowManager.addView(surfaceView, layoutParams);
        surfaceView.getHolder().addCallback(this);
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Intent notificationIntent = new Intent(this, MainActivity.class);

        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0,
                notificationIntent, 0);

        Notification notification = new NotificationCompat.Builder(this)
                //.setSmallIcon(R.mipmap.app_icon)
                .setContentTitle("Background Video Recorder")
                .setContentText("")
                .setContentIntent(pendingIntent).build();

        startForeground(MainActivity.NOTIFICATION_ID_RECORDER_SERVICE, notification);
        return Service.START_NOT_STICKY;
    }

    // Method called right after Surface created (initializing and starting MediaRecorder)
    @Override
    public void surfaceCreated(SurfaceHolder surfaceHolder) {
        camera = Camera.open(1);
        mediaRecorder = new MediaRecorder();
        camera.unlock();

        mediaRecorder.setPreviewDisplay(surfaceHolder.getSurface());
        mediaRecorder.setCamera(camera);
        mediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
        mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
        mediaRecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_720P));

        FileUtil.createDir("/storage/emulated/0/Study/Camera");
        mediaRecorder.setOutputFile("/storage/emulated/0/Study/Camera/" + Long.toString(System.currentTimeMillis()) + ".mp4");

        try { mediaRecorder.prepare(); } catch (Exception e) {}
        mediaRecorder.start();

        try {
            camera.setPreviewDisplay(surfaceHolder);
        } catch (IOException e) {
            e.printStackTrace();
        }

        Runnable runnable = new PictureThread(camera);
        Thread thread = new Thread(runnable);
        thread.start();
    }

    // Stop recording and remove SurfaceView
    @Override
    public void onDestroy() {
        mediaRecorder.stop();
        mediaRecorder.reset();
        mediaRecorder.release();

        camera.lock();
        camera.release();

        windowManager.removeView(surfaceView);
    }

    @Override
    public void surfaceChanged(SurfaceHolder surfaceHolder, int format, int width, int height) {}

    @Override
    public void surfaceDestroyed(SurfaceHolder surfaceHolder) {}

    @Override
    public IBinder onBind(Intent intent) { return null; }
}

Edit: I have now written a thread PictureThread. This thread is started from RecorderService and tries to take a picture while video recording.

public class PictureThread implements Runnable {
    private final static String TAG = PictureThread.class.getSimpleName();

    private Camera camera;

    PictureThread(Camera camera) {
        this.camera = camera;
    }

    @Override
    public void run() {
        camera.startPreview();
        camera.takePicture(shutterCallback, rawCallback, jpegCallback);
    }

    Camera.ShutterCallback shutterCallback = new Camera.ShutterCallback() {
        public void onShutter() {
        }
    };

    Camera.PictureCallback rawCallback = new Camera.PictureCallback() {
        public void onPictureTaken(byte[] data, Camera camera) {
        }
    };

    Camera.PictureCallback jpegCallback = new Camera.PictureCallback() {
        public void onPictureTaken(byte[] data, Camera camera) {
            Log.i(TAG, "onPictureTaken - jpeg");
        }
    };
}

Unfortunately jpegCallback gets never called (i.e. the Log message is never printed). When I open the camera app of my tablet then I can take pictures while video recording, so this should be possible.

I have also tried the Camera2 API example as suggested by Alex Cohn (https://github.com/mobapptuts/android_camera2_api_video_app). Recording a video works and also taking a picture works but when I try to take a picture while recording, no picture is created (but also no error). Nevertheless, I have found this example app not working very reliable (perhaps there is another example app).

Edit 2: The shutterCallback and rawCallback of takePicture gets called but the data of the rawCallback is null. The jpegCallback gets never called.. Any idea why and how this can be solved? I have also tried to wait in the thread for a period of time to give the callback time for being called and I have tried to make the callbacks static in my main activity (so that it gets not garbage collected). Nothing worked.