[Android Q&A, Help & Troubleshooting] Helveticus99:
Hello everybody

Unfortunately, I have too few post to make a thread in the " Android Software Development" forum. I would be very happy if this post can be moved to it.

I have used the Camera2 API to implement a background video recorder running as a service and recording from the front cam. For this I have created a new SurfaceView, set its size to 1x1 and moved it to the top left corner. My code is shown below. I'm using Android 5.1.

With the Camera API it worked very well but unfortunately the frame rate is only at 20 fps (and when I increase the exposure compensation it drops even more), although with the Open Camera app I have 30 fps also with increased exposure compensation. That is why I want to try Camera2 API (hoping to get higher fps). Unfortunately, I'm getting the following error:

Here is my code:

public class RecorderServiceCamera2 extends Service implements SurfaceHolder.Callback {
private WindowManager windowManager;
private SurfaceView surfaceView;
private CameraDevice mCamera;
private MediaRecorder mediaRecorder = null;
private CaptureRequest mCaptureRequest;
private CameraCaptureSession mSession;

@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;
}

@Override
public void surfaceCreated(final SurfaceHolder surfaceHolder) {
mediaRecorder = new MediaRecorder();

try {
CameraManager manager = (CameraManager) getSystemService(CAMERA_SERVICE);
String[] cameras = manager.getCameraIdList();
CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameras[1]);
StreamConfigurationMap configs = characteristics.get(
CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
Size[] sizes = configs.getOutputSizes(MediaCodec.class);

final Size sizeHigh = sizes[0];

manager.openCamera(cameras[1], new CameraDevice.StateCallback() {
@Override
public void onOpened(@NonNull CameraDevice camera) {
mCamera = camera;
mediaRecorder.setPreviewDisplay(surfaceHolder.getSurface());
mediaRecorder.setVideoSource(MediaRecorder.VideoSource.SURFACE);
mediaRecorder.setMaxFileSize(0);
mediaRecorder.setOrientationHint(0);

mediaRecorder.setOutputFile("test.mp4");
try { mediaRecorder.prepare(); } catch (Exception ignored) {}
List<Surface> list = new ArrayList<>();
list.add(surfaceHolder.getSurface());

try {
CaptureRequest.Builder captureRequest = mCamera.createCaptureRequest(CameraDevice.TEMPLATE_RECORD);
captureRequest.addTarget(surfaceHolder.getSurface());
mCaptureRequest = captureRequest.build();
} catch (CameraAccessException e) {
e.printStackTrace();
}

try {
mCamera.createCaptureSession(list, new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(@NonNull CameraCaptureSession session) {
mSession = session;
}

@Override
public void onConfigureFailed(@NonNull CameraCaptureSession session) {
mSession = session;
}
}, null);
} catch (CameraAccessException e) {
e.printStackTrace();
}

mediaRecorder.start();

try {
mSession.setRepeatingRequest(mCaptureRequest,
new CameraCaptureSession.CaptureCallback() {
@Override
public void onCaptureStarted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, long timestamp, long frameNumber) {
super.onCaptureStarted(session, request, timestamp, frameNumber);
}

@Override
public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {
super.onCaptureCompleted(session, request, result);
}

@Override
public void onCaptureFailed(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull CaptureFailure failure) {
}
}, null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}

@Override
public void onDisconnected(@NonNull CameraDevice camera) {
}

@Override
public void onError(@NonNull CameraDevice camera, int error) {
}
}, null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}

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

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; }
}