25-second square (1:1) ad on Seedance 2.5: $6.42 at 480p

A 25-second 1:1 Seedance 2.5 clip costs $6.42 at 480p, $14.45 at 720p and $35.54 at 1080p on Sume. At 480p the square frame is the cheapest of the six ratios, about 4.4 percent under 16:9 (read 2026-10-09).

Square ad tests by length

Feed placements still use 1:1. Seedance 2.5 can generate a square clip of up to 30 seconds in one job, so a long product story does not need stitching. The question is how long the test should be.

Test short, publish long

A 5-second 480p square costs $1.28; five of them cost $6.42, more than one 10-second 720p clip ($5.78). Test the hook with several short drafts, then spend the 25-second budget on the winner.

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": "Square product story: a ceramic mug is thrown on a wheel, glazed, fired and placed on a sunlit shelf", "duration": 25, "resolution": "480p", "aspect_ratio": "1:1"}
job = requests.post(API, headers={**H, "Idempotency-Key": "square-story-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

A test plan that ends in a 25-second final

Run four 5-second 480p square drafts ($5.14), pick the best, then render the 25-second final at 720p ($14.45). The total is $19.58.

The same plan with a 1080p final costs $40.67. The final dominates the budget, which is why the draft stage should kill weak ideas early and cheaply.

Going from 480p to 720p multiplies the 25-second price by 2.25. Going from 720p to 1080p multiplies it by 2.46.

What to check

• Submit reserves the full list price times 1.25, so the 25-second 1080p version needs the whole amount in the balance before it starts.
• No v1 model accepts a seed, so a 480p draft and a 1080p final are two separate generations that can differ.
• Cancel works only before generation starts; after that the job completes or fails on its own.
• Read supported_durations from GET /v1/videos/models rather than hardcoding 4 to 30.