Retro TV bumper in 4:3: 11 s of Seedance 2.5 costs less at 480p

An 11-second 4:3 Seedance 2.5 clip costs $2.90 at 480p and $6.40 at 720p on Sume. Seedance 2.5 is token-priced, and at 480p the 4:3 frame is slightly cheaper than 16:9, which reverses at 720p (read 2026-10-09).

A 4:3 frame for a retro look

A fake-broadcast bumper, a VHS-style intro or a slide-deck loop wants the old square-ish frame. Seedance 2.5 lists 4:3 among its six ratios (21:9, 16:9, 4:3, 1:1, 3:4, 9:16), and 11 seconds is a valid length because the model takes every whole second from 4 to 30.

Request

Nothing special is needed for 4:3: set aspect_ratio and keep resolution at 480p for the proof run.

import os, time, requests

API = "https://api.sume.com/v1/videos"
H = {"Authorization": "Bearer " + os.environ["SUME_API_KEY"]}
body = {"model": "seedance-2.5", "prompt": "Retro 1990s TV station ident, scanlines, a spinning logo on a blue grid, soft tape noise", "duration": 11, "resolution": "480p", "aspect_ratio": "4:3"}
job = requests.post(API, headers={**H, "Idempotency-Key": "bumper-retro-001"}, json=body, timeout=60).json()
deadline = time.time() + 1800
while time.time() < deadline:
    time.sleep(30)
    job = requests.get(job["polling_url"], headers=H, timeout=60).json()
    if job["status"] == "completed":
        print(job["unsigned_urls"][0], job["usage"]["cost"])
        break
    if job["status"] in ("failed", "cancelled"):
        print(job["status"], job.get("error"))
        break

Where the savings stop

At 480p the cheapest frame for 11 seconds is 1:1 at $2.82, then 4:3 and 3:4 at $2.90, and 16:9, 9:16 and 21:9 at $2.96. The spread from cheapest to dearest is $0.13.

Moving the same 4:3 clip from 480p to 720p changes the total from $2.90 to $6.40. That jump is 2.20 times, far bigger than any ratio effect. If you want to economize on a bumper, lower the resolution first.

A retro bumper is also forgiving about resolution. A VHS look hides softness, so a 480p render may be the final, not only the draft.

Things to know

• The 4:3 saving at 480p is small, under 2 percent of the 16:9 price. Pick the ratio for the placement, not the discount.
• At 720p and 1080p the order flips: 4:3 and 3:4 cost a little more than 16:9. Re-run the price check when you change resolution.
• Do not rely on auto or adaptive for price planning; pin the ratio you will publish.
• Scanlines and tape noise are prompt effects. If you want exact analog overlays, add them in an edit step after generation.