No-reference blockiness detector

A small, self-contained Python script that finds the block grid (macroblocking) in a single frame without a reference image, using the Wang-Bovik frequency-domain method: it takes the average gradient across rows and columns, runs an FFT, and measures the peak at the block-grid frequency and its harmonics. Works on live and UGC where no original exists. Includes a built-in --demo self-test. Needs numpy; Pillow optional for image input. Triage tool, not a calibrated metric. (ZIP containing 1 file