Kling 4.0 Flash vs Gemini Omni Flash 1.1: two Flash models, two limits

Kling 4.0 Flash and Gemini Omni Flash 1.1 share a word and little else. Kling 4.0 Flash is an early-access tier at 3 to 20 seconds, 720p only, according to the fal explainer (read 2026-10-05). Omni Flash 1.1 is available on Sume now as gemini-omni-flash-1.1: 3 to 10 seconds, 360p to 4K, 16:9 or 9:16, with sound always on, and $1.25 for a 10 second 720p clip.

If you searched for a Flash model because you want a cheap, fast draft, the comparison is useful, but only one of the two can be called from the Sume API today.

What each one is

The fal page says Kling 4.0 was announced on 2026-09-28, with Flash in limited early access since then, and a full launch in October 2026. The full model is listed at 3 to 30 seconds with 720p, 1080p and 4K, up to 10 keyframe images, and up to 15 references. Flash is 3 to 20 seconds at 720p, with 8-bit SDR output. The same page says Kling 4.0 is "coming to fal", so treat any API route as not yet confirmed.

On Sume, Omni Flash 1.1 reports a 3 to 10 second range, resolutions of 360p, 720p, 1080p and 4K, and only 16:9 or 9:16. Audio is native and always on. It accepts up to 10 image references and up to 3 video references, each no longer than 3 seconds, which you cite in the prompt as <IMAGE_REF_0> and <VIDEO_REF_0>, and it has a video edit mode through the Video Router video_url field.

The two Flash models, side by side

Price on Sume

Omni's price is per second and moves with resolution. At 10 seconds it is $0.38 at 360p, $1.25 at 720p, $1.88 at 1080p and $3.75 at 4K. The shortest clips are small: 3 seconds at 720p is $0.38 and 4 seconds is $0.50. Prices are Sume billable amounts, the provider list times 1.25, taken from the pricing package and reserved at submit.

No Kling 4.0 Flash price is listed on the page used here, so no comparison of cost is possible. The nearest Kling model on Sume is kling-3 (Kling Video v3 Pro), which accepts 4 to 15 seconds at 720p or 1080p in 16:9, 9:16 or 1:1, and bills $0.14 per second with audio off or $0.21 with audio on.

An Omni Flash request

This builds an Omni request that uses a first image reference as in the video docs, and prints it. It sends nothing unless SUME_API_KEY is set.

import json, os

payload = {
    "model": "gemini-omni-flash-1.1",
    "prompt": "Use <IMAGE_REF_0> as the product. Slow orbit, soft window light.",
    "duration": 6,
    "resolution": "720p",
    "aspect_ratio": "9:16",
    "input_references": [
        {"type": "image_url", "image_url": {"url": "https://example.com/product.png"}}
    ],
}
print(json.dumps(payload, indent=2))

if os.environ.get("SUME_API_KEY"):
    import requests
    r = requests.post(
        "https://api.sume.com/v1/videos",
        headers={"Authorization": "Bearer " + os.environ["SUME_API_KEY"]},
        json=payload,
        timeout=60,
    )
    print(r.status_code)

Using Omni as the draft model

The cheapest way to use Omni Flash as a draft model is 360p. A 10 second clip at 360p is $0.38, a third of the 720p price, which is enough to judge composition, motion and the sound mix before a 720p or 1080p final. Because audio is always on, you cannot switch it off to save money, so compare it with kling-3 audio off if you only need silent footage.

Omni also has an edit mode: send video_url through the legacy Video Router route and the model reworks an existing clip, with reference clips capped at 3 seconds each. That is a different job from generating a new shot, and the fal page on Kling 4.0 does not mention editing for Flash.

Where to go for longer clips

For a 20 second clip there is no Omni equivalent, because it stops at 10 seconds. Use seedance-2.5 or wan-3.0 for lengths between 11 and 30, or run two Omni clips and join them. When Kling 4.0 appears in the Sume catalog, GET /v1/videos/models is where it will list its durations and ratios. Until then, read the video generation docs for the ranges.