HappyHorse 1.1 lists 9 aspect ratios; Omni on Sume lists 2

Alibaba's HappyHorse reference-to-video reference lists nine aspect ratios: 16:9 (default), 9:16, 3:4, 4:3, 4:5, 5:4, 1:1, 9:21 and 21:9 (Alibaba Model Studio, read 2026-10-09). Google lists 9:16 and 16:9 for Gemini Omni Flash (Google Omni docs, read 2026-10-09), and Sume passes those two through. For 4:5 or 1:1 you need another model or a crop.

What does each row accept?

Where do I read Sume's ratios?

Each Sume model reports its own supported_aspect_ratios from GET /v1/videos/models; the video docs list the full vocabulary (16:9, 9:16, 1:1, 4:3, 3:4, 3:2, 2:3, 21:9, 9:21) and say each model shows the subset it accepts. Its example seedance-2 row lists 21:9, 16:9, 4:3, 1:1, 3:4 and 9:16. Read the live list, not the example.

import os, requests

r = requests.get("https://api.sume.com/v1/videos/models",
                 headers={"Authorization": f"Bearer {os.environ['SUME_API_KEY']}"})
for m in r.json()["data"]:
    print(m["id"], m.get("supported_aspect_ratios"))

What if you need 4:5?

Find a model whose list includes 4:5, or generate 9:16 and crop with the video filter for $0.02 a job. Sume lists no HappyHorse id (catalog read 2026-10-09).