public void requestPreview(final PreviewCallback callback) {
        mainHandler.post(() -> {
            if (!open) {
                Log.d(TAG, "Camera is closed, not requesting preview");
                return;
            }

            cameraThread.enqueue(() -> cameraManager.requestPreviewFrame(callback));
        });
    }
Changes the settings for Camera.

@param callback {@link CameraParametersCallback}
zxing-android-embedded/src/com/journeyapps/barcodescanner/camera/CameraInstance.java