Cascaded diffusion at 4K without the artifacts

Coarse to fine, cleanly

Generating directly at 4K is expensive and prone to repetition. A cascade instead generates a confident low-resolution frame and then super-resolves it in stages, each stage adding detail conditioned on the last.

The trick is suppressing the tiling seams and texture loops that cascades are notorious for — we overlap windows and re-noise boundaries so the final frame holds up under a hero crop.