code: protected Camera openCamera() throws CameraAccessException, IOException
      {
          Camera camera = Camera.open();
  
          if (camera == null)
          {
              throw new CameraAccessException(CameraAccessException.CAMERA_ERROR);
          }
          Camera.Parameters params = camera.getParameters();
  
          params.setPreviewSize(mWidth, mHeight);
          params.setPreviewFormat(ImageFormat.NV21);
          params.setPreviewFpsRange(30000, 30000);
          camera.setParameters(params);
          camera.setPreviewCallback(new Camera.PreviewCallback()
            {
                public void onPreviewFrame(byte[] data, Camera camera)
                {
                    setImageData(data);
                }
            });
          return camera;
      }
docs: Opens the camera and starts capturing images.
  <p>
  The default implementation uses <i>ImageFormat.NV21</i>
  and tracks at 30fps. It captures 1280 x 960 images.
  The width and height is obtained from mWidth and mHeight
  so constructors may set this to change the image size.
  @return
  @throws CameraAccessException
  @throws IOException