Yuv (NV21) image converting to bitmap

I am trying to capture images from camera preview and do some drawing on it. The problem is, I have only about 3-4 fps of drawing, and half of the frame processing time is receiving and decoding NV21 image from camera preview and converting to bitmap. I have a code to do this task, which I found on another stack question. It does not seem to be fast, but I do not know how to optimize it. It takes about 100-150 ms on Samsung Note 3, image size 1920x1080. How can I make it work faster?

Code :

public Bitmap curFrameImage(byte[] data, Camera camera)
{
    Camera.Parameters parameters = camera.getParameters();
    int imageFormat = parameters.getPreviewFormat();

    if (imageFormat == ImageFormat.NV21)
    {
        YuvImage img = new YuvImage(data, ImageFormat.NV21, prevSizeW, prevSizeH, null);
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        img.compressToJpeg(new android.graphics.Rect(0, 0, img.getWidth(), img.getHeight()), 50, out);
        byte[] imageBytes = out.toByteArray();
        return BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.length);
    }
    else
    {
        Log.i(TAG, "Preview image not NV21");
        return null;
    }
}

The final format of image has to be bitmap, so I could then do processing on it. I've tried to set Camera.Parameters.setPreviewFormat to RGB_565, but could not assign camera params to camera, I've read also that NV21 is the only available format. I am not sure about that, whether it is possible to find solution in these format changes.

Thank you in advance.