Omni Flash vs Grok Imagine 1.0 — Video API Billing Models Compared
You're adding short video generation to your app and comparing Gemini Omni Flash against Grok Imagine 1.0. They produce different styles and carry different capabilities — but the billing model difference is where most developers get surprised. Omni Flash charges a flat price per clip. Grok Imagine 1.0 charges per second of output. Depending on the clip duration your product needs, one can cost 50–200% more than the other for identical output volume.
This article breaks down exactly where each model wins on cost, with math you can apply to your own workload before writing a single line of integration code. Both models are available through a single GenRelay endpoint.
What Are the Two Billing Models?
Per-generation billing means you pay a fixed price for each clip you generate, regardless of its duration. Gemini Omni Flash uses this model. Whether the clip runs 8 seconds or 15 seconds, you pay the same flat rate.
Per-second billing means you pay based on the exact number of seconds of video output. Grok Imagine 1.0 uses this model. A 5-second clip costs exactly half what a 10-second clip costs.
The core trade-off: per-generation billing gives you cost predictability for variable clip lengths; per-second billing scales linearly and is cheaper for short clips.
What Does Each Model Cost on GenRelay?
As of September 2026:
| Model | Billing model | 720p price | 1080p price | Mode |
|---|---|---|---|---|
| Gemini Omni Flash | Per generation | $0.10 / clip | $0.15 / clip | Text-to-video |
| Grok Imagine 1.0 | Per second | $0.010 / s | $0.010 / s | Text-to-video |
| Grok Imagine 1.5 | Per second | $0.022 / s | $0.022 / s | Image-to-video |
Omni Flash's flat rate applies regardless of clip duration. Grok 1.0 charges $0.010 for every second of video generated, making duration the only variable in your cost equation.
At What Clip Length Do the Models Break Even?
The breakeven point is the duration at which both models cost the same per clip.
720p breakeven calculation:
Omni Flash = $0.10 per clip (fixed)
Grok 1.0 = $0.010 × duration
Breakeven: $0.10 / $0.010 = 10 seconds
1080p breakeven calculation:
Omni Flash = $0.15 per clip (fixed)
Grok 1.0 = $0.010 × duration
Breakeven: $0.15 / $0.010 = 15 seconds
Per-clip cost at 720p across durations:
| Clip duration | Omni Flash 720p | Grok 1.0 720p | Cheaper option |
|---|---|---|---|
| 4s | $0.10 | $0.04 | Grok 1.0 (saves 60%) |
| 6s | $0.10 | $0.06 | Grok 1.0 (saves 40%) |
| 8s | $0.10 | $0.08 | Grok 1.0 (saves 20%) |
| 10s | $0.10 | $0.10 | Equal |
| 15s | $0.10 | $0.15 | Omni Flash (saves 33%) |
| 20s | $0.10 | $0.20 | Omni Flash (saves 50%) |
| 30s | $0.10 | $0.30 | Omni Flash (saves 67%) |
The pattern is straightforward: Grok 1.0 is cheaper below 10 seconds. Omni Flash is cheaper above 10 seconds. At exactly 10 seconds, the cost is identical.
Cost at Scale: 1,000 Clips per Month
Monthly cost for 1,000 clips at 720p, varying clip duration:
| Clip duration | Omni Flash 720p | Grok 1.0 720p | Omni Flash 1080p | Grok 1.0 1080p |
|---|---|---|---|---|
| 5s | $100 | $50 | $150 | $50 |
| 10s | $100 | $100 | $150 | $100 |
| 15s | $100 | $150 | $150 | $150 |
| 20s | $100 | $200 | $150 | $200 |
| 30s | $100 | $300 | $150 | $300 |
At 30s per clip and 1,000 clips/month, Grok 1.0 at 720p costs $300 vs Omni Flash at $100 — a 3× difference. For products generating long clips at volume (explainer videos, tutorials, scene renders), Omni Flash's flat fee creates significant savings.
For a full cost comparison across all GenRelay video models, see AI video API cost guide.
How Do I Call Each Model via GenRelay?
Both models use the same POST /v1/videos/generations endpoint — only the model field and available parameters differ. Video generation is asynchronous: submit a job, get a job ID, then poll until the status is succeeded.
Gemini Omni Flash (per-generation):
import os, time, requests
GENRELAY_API_KEY = os.environ["GENRELAY_API_KEY"]
def generate_omni_flash(prompt: str, resolution: str = "720p") -> str:
"""Submit and poll an Omni Flash video job. Returns video URL."""
resp = requests.post(
"https://genrelay.ai/v1/videos/generations",
headers={"Authorization": f"Bearer {GENRELAY_API_KEY}"},
json={
"model": "omni-flash",
"prompt": prompt,
"resolution": resolution # "720p" → $0.10 | "1080p" → $0.15
}
)
resp.raise_for_status()
job_id = resp.json()["id"]
while True:
status = requests.get(
f"https://genrelay.ai/v1/videos/generations/{job_id}",
headers={"Authorization": f"Bearer {GENRELAY_API_KEY}"}
).json()
if status["status"] == "succeeded":
return status["output"]["url"]
if status["status"] == "failed":
raise RuntimeError(f"Job failed: {status.get('error')}")
time.sleep(10)
url = generate_omni_flash("A timelapse of a neon-lit cityscape at dusk", "720p")
print(url) # Cost: $0.10 regardless of clip length
Grok Imagine 1.0 (per-second):
import os, time, requests
GENRELAY_API_KEY = os.environ["GENRELAY_API_KEY"]
def generate_grok_video(prompt: str, duration: int = 8) -> str:
"""Submit and poll a Grok 1.0 video job. Returns video URL."""
resp = requests.post(
"https://genrelay.ai/v1/videos/generations",
headers={"Authorization": f"Bearer {GENRELAY_API_KEY}"},
json={
"model": "grok-imagine-1.0",
"prompt": prompt,
"duration": duration # seconds; cost = duration × $0.010
}
)
resp.raise_for_status()
job_id = resp.json()["id"]
while True:
status = requests.get(
f"https://genrelay.ai/v1/videos/generations/{job_id}",
headers={"Authorization": f"Bearer {GENRELAY_API_KEY}"}
).json()
if status["status"] == "succeeded":
return status["output"]["url"]
if status["status"] == "failed":
raise RuntimeError(f"Job failed: {status.get('error')}")
time.sleep(15)
# 8-second clip costs $0.080 (8 × $0.010)
url = generate_grok_video("A lone wolf running across a frozen tundra", duration=8)
print(url)
Switching between models requires only changing the model field — the polling logic and response schema stay the same. For deeper integration patterns, see the Omni Flash video API guide and Grok video generation API guide.
How Do the Models Differ Beyond Pricing?
Billing model is the biggest cost driver, but the models also differ in capability:
| Dimension | Gemini Omni Flash | Grok Imagine 1.0 |
|---|---|---|
| Input mode | Text-to-video | Text-to-video |
| Image-to-video | Not supported | Not supported (use Grok 1.5) |
| Clip duration control | Fixed per generation | Configurable via duration param |
| 720p pricing | $0.10 / clip | $0.010 / s |
| 1080p pricing | $0.15 / clip | $0.010 / s |
| Best for | Longer clips, cost cap needed | Short clips, duration control |
If your use case requires image-to-video (animating a reference image), neither Omni Flash nor Grok 1.0 applies — use Grok Imagine 1.5 at $0.022/s or Veo 3.1 i2v mode instead.
Which Model Should You Choose?
Use Omni Flash when:
- Your clips regularly exceed 10 seconds — the flat fee becomes significantly cheaper above the breakeven
- You need 1080p output at a predictable cost cap ($0.15/clip regardless of duration)
- You're building a feature where clip length varies widely and you want to avoid variable billing surprises
- Long-form content (product demos, scene renders, explainers) is your primary output
Use Grok Imagine 1.0 when:
- Your clips are consistently under 8 seconds — you pay only for what you generate
- You're producing short social content, animated thumbnails, or quick product snippets
- You need to control exact clip duration via the duration parameter
- Low-cost experimentation and prototyping, where short clips reduce per-test cost
Use Grok Imagine 1.5 when:
- You need image-to-video (animate an existing image) — Grok 1.0 is text-to-video only
- The $0.022/s rate is justified by the motion quality requirements of your use case
FAQ
Does Omni Flash let me control clip duration?
Omni Flash bills per generation regardless of clip length, which means you're paying a fixed cost independent of the output duration. Check the current parameter options in the GenRelay console — supported duration settings may vary as the model is updated.
Does Grok Imagine 1.0 support 1080p output?
Grok 1.0 charges $0.010/s at its supported resolution tiers. Verify current resolution availability through the GenRelay model catalog, as supported options may update.
Can I switch models in production without rewriting my integration?
Yes. Both models share the same endpoint (POST /v1/videos/generations) and the same async polling pattern. Changing the model field is all that's needed; parameter names may differ slightly so validate your payload against each model's spec.
Are failed generations billed?
No. Jobs that end with status: "failed" are not charged. You're only billed for successfully completed video clips.
Is there a free tier for testing?
GenRelay includes free credits on new accounts that cover initial testing with both Omni Flash and Grok models. The $14/mo plan includes a monthly credit allocation before pay-as-you-go billing applies.
What's the generation latency for each model?
Video generation is asynchronous and latency varies by load and clip complexity. Poll at 10-second intervals for Omni Flash and 15-second intervals for Grok models as a starting baseline. For a latency breakdown by resolution and model, see the AI video API latency guide.