Android Camera Preview Callback slow down We need the constant fps

Hello folk last few day I faced the issue on Camera Preview Callback, I want to scan the each frame

inside the added PreviewCallback, I have device (motorola g) that give me the 30 fps. below is the

code inside the preview Callback.

private PreviewCallback previewCallback = new PreviewCallback() {

        /**
         * {@inheritDoc}
         */
        @Override
        public void onPreviewFrame(byte[] data, Camera cam) 
        {

          if (data == null) throw new NullPointerException();
          Camera.Size size = cam.getParameters().getPreviewSize();
          if (size == null) throw new NullPointerException();

          int width = size.width;

          int height = size.height;

            // maximum value of the range of sum (Red) values in each frame 1/10 part of every 5th 
            // pixel red value sum ( if all pixels consider the red(255) then max value of sum of r)
          final double analysisFrameSize = (((width * height)/100)/5f)* 255;

          ImageProcessing.setMaxPixelPerFrame(analysisFrameSize);

          ImageProcessModel model = ImageProcessing.decodeYUV420SPtoRedAvg(data.clone(), width, height);

          List<Integer> furtherAnaylisList = model.getmFurtherAnalysisList();

          final int frameSize = (((width * height)/100)/5);

          int redAvg = (furtherAnaylisList.get(0) / frameSize);

          int green = (furtherAnaylisList.get(1) / frameSize);

          int blue = (furtherAnaylisList.get(2) / frameSize);

          Log.println(TAG,String.format("AvgRed:%2d,AvgGree:%2d,AvgBlue:%2d",redAvg,green,blue));

        }
    };

Is program slow down the frame rate inside the preview callback because after write the code it slow down fps 30 fps to 22 fps, I have no issues with 22 fps but it is not constant.

Can I set the camera for give me the 22 or 30 fps constant.

Thank you in advance.