1. A method of determining video image scaling in a decoded enlarged image, comprising: receiving a decoded scaled input image comprising a plurality of pixels, wherein the input image has a scaling ratio relative to an original image; detecting blocking boundary artifact pixels in the input image; determining a sum of pixel values on the input image for each blocking boundary artifact; detecting the pixel distance value between each pair of neighboring block boundaries; and determining said scaling ratio from the input image received based on only said pixel distance value and said sum of pixel values of the input image received.