The Empty
Leg

Picture

Twelve 8-second clips joined with no transitions, with a 3-second title card in front and a 6-second end card behind (the AI disclosure is on the end card). Each clip starts from the previous clip's actual last frame.

Narration

Edge TTS en-GB-RyanNeural at -5%, one voice and one pace throughout. Each line starts 0.55 s into its block. Block 2 is the densest line in the film and runs long, so its audible start was moved earlier to 0.30 s; no word was changed to make it fit.

Score

“The Geometry of Calm”, AI-generated. The original runs 94.85 s and was stretched 1.24% to fit. It was not cut. Its opening is nearly silent for four seconds, which is how the piece starts, and it was left that way.

Mix

Full-band, explicit ducking envelope, 5.0 dB under every one of the twelve lines, 150 ms in and 400 ms out; the eleven music-only gaps measure +0.0 dB. Delivered at −14.1 LUFS / −1.5 dBTP. The voice sits at least 6.2 dB above the music in every block. Trade-off: the loudest four seconds are meant to land under the film's one claim (block 11). Measured, the voice there would have been 0.8 dB below the music, so the claim would not have been audible. The swell was moved to the music-only gap right after it (1:27–1:31), where it leads the next loudest passage by 1.9 dB, short of the 3 dB aimed for.

Overlays

Station name and title only, on the six stops. No numbers, so the end card does not need a “figures are illustrative” line.

Form

The video never plays; only its currentTime is driven by scroll position. The camera really is moving, scroll only drives time.

Length

1:16. Connectors are sped up 2×, not trimmed. Stops keep their full length. Block-start mapping error is at most 0.088 s (threshold 0.1 s).

Sound

Silent by design. Browsers block autoplay with sound, and a film designed to be silent reads better than one that was muted. The argument is carried by the text cards.

Encoding

1080p (the upscaled download from Flow's gallery, not an upscale of ours), CRF 30, one keyframe every four frames, 21.3 MiB. Cloudflare Pages answered Range requests with 200 instead of 206 in earlier tests, and without Range there is no scrubbing, so the video is served from GitHub Pages.

Fallbacks

Three paths: prefers-reduced-motion, video not ready after 12 s, and load error. The fallback layout is complete and readable; static frames enter the DOM only on a fallback path.

• Only the hero box is green. The world is cool grey and the hero box is the one saturated colour in the film. Using the hero box as a reference image turned other boxes green, and the style line “single brand-green highlight” painted green on assets that had no hero in them, so the supporting assets were generated without references and with a separate style line.
• The opening line is a floor, not a headline. “More than one in five” holds under every counting method found (by boxes and by TEU-miles in Sea-Intelligence's 2026 analysis, and in Drewry's 2016 count of all containers moved by sea). “One in three” is a single consultancy's single method, so it was not used. The rest of the script is hedged the same way: many boxes, stacks can climb, it usually leaves on a booking, much of the cost.
• The one sentence with an edge. “The empty leg is never free, because much of its cost is carried in the price of the full ones” is the only claim in the film. Carriers do pass repositioning costs on to head-haul shippers, and give back-haul shippers discounts to recover some of it. It blames nobody and was deliberately not softened.
• Words in a prompt get printed. The word “brand” ended up painted on container doors, and the model stamps ID blocks on any large flat door end. The word was removed from the clip prompts, and the small door-end marks that remained on blocks 4 and 10 were filled in post-production from the box's own green.

Known flaws, not fixed

• Six short dissolve ghosts where the model morphed toward the last-frame anchor, at about 10.6, 21.3, 46.7, 52.6, 69.9 and 84.5 s of the master (0.3–0.8 s each).
• Small floor numerals in block 3; a faint speck on a roof in block 6; a faint red hull on a background ship in block 10; the ship in block 12 is still alongside at the end.
• The open-door depot is a visual device. Real depots mostly stack with doors shut, and the narration never says the doors are open.