No-reference judder & stutter detector

A small, self-contained Python script that inspects a SEQUENCE of frames for temporal artifacts WITHOUT a reference, using three timeline checks: (1) duplicate/dropped-frame detection via the mean absolute luminance difference between consecutive frames (a near-zero difference flags a held/repeated frame; an abnormally large jump after a run of holds flags a drop); (2) pulldown-cadence detection that recognizes a repeating 3:2 (held, held, held, new, new) or 2:2 pattern from the duplicate sequen