Gemini Omni reference errors: 10 images, 3 clips of 3 s, 16:9 or 9:16

gemini-omni-flash-1.1 has the tightest reference rules in the Video Router catalog. It takes at most 10 reference images and 3 reference videos of at most 3 seconds each. It refuses audio references and bitrate_mode, and it accepts only 16:9 or 9:16. Each limit has its own named 400, so the message tells you which one you hit.

Each rule and its message

The messages come from the validation code on main. The pattern is the model name plus the limit, which makes them easy to match in logs.

What the schema cannot see

The count of clips is checked at the API, but the three-second length per clip is a rule stated in the message and the catalog notes, not something the validation can measure on a URL. Measure each reference clip before you upload. If a clip is longer, cut it first: video_trim makes a new MP4 from a start and an end or duration on a stored clip.

Trim, then submit

The snippet shows the trim request body for a 3-second reference cut from a stored clip. It uses the documented video_url plus start and duration fields and prints the body; set SEND=1 to submit it, which creates a billed job. Use your own media.sume.com URL and a fresh idempotency key per request.

import os
import requests

body = {
    "video_url": "https://media.sume.com/artifacts/artf_demo/talk.mp4",
    "start": 4,
    "duration": 3,
}
print(body)
if os.environ.get("SEND") == "1":
    r = requests.post("https://api.sume.com/v1/video-trim",
                      headers={"Authorization": "Bearer " + os.environ["SUME_API_KEY"],
                               "Idempotency-Key": "trim-ref-001"},
                      json=body, timeout=60)
    print(r.status_code)

When another model is better

If you need audio references, longer reference clips or other aspect ratios, use Wan 3.0 or a Seedance model. If you need native 4K, Gemini Omni is one of two models that take it. The Video Router docs table lists the same limits for the model, so the code and docs agree on everything here except the audio flag covered in another post.

One last tip: validate the aspect ratio before you generate any assets for the shot. A square or 4:3 composition made for another model cannot be sent here, and cropping a finished reference to 16:9 or 9:16 afterwards changes what the model sees. Decide the frame shape first, then choose the references to fit it, then check the counts. That order avoids rework when a model has narrow rules like these.