You've seen it happen. You feed a video into an image background remover, export the result, and the subject's hair turns into a cardboard cutout. Fast hand movements smear into semi-transparent ghosts. The edge between foreground and background flickers frame after frame. The model probably didn't fail. You did—by treating video as a stack of independent photos. I've been building with video segmentation pipelines for the past year, and the single biggest mistake I see developers make is ...