Base Plate — Pan — City Skyline
A skyline scrolling at a constant 3.5 pixels per frame: pure horizontal translation with no rotation or scale change. The lit windows give sparse high-contrast features to track, and the constant velocity means the correct answer for interpolation and optical flow is known exactly. One of eight shared base plates: every AI-video suite in this library degrades one of these rather than inventing its own footage, so results across suites are comparable. Encoded at CRF 14 — well above the house CRF 30 — because a reference compressed as hard as the material under test puts the measurement floor above the effect being measured.