AI video API duration limits: how long a clip each model will make
Clip length is the constraint that decides more pipelines than price does.
| Model | Duration | Billing | Cost at default |
|---|---|---|---|
| Seedance | 3–15s, any integer | 5 credits/second | 25 credits |
| Kling | 5 or 10s | 7 credits/second | 35 credits |
| Veo 3 | 8s only | per clip | 100 credits |
Fixed buckets cost more than the rate suggests
Only Seedance bills per second. The rest round you up to the next available length — ask for 7 seconds from a model that offers 5 or 10 and you pay for 10.
On variable-length work that rounding can exceed the difference in per-second rates entirely, which is why comparing headline rates alone is misleading.
No model makes long clips
The longest single call on the platform is 15 seconds. Anything longer is several clips stitched afterwards, which also means several jobs, several concurrency slots, and continuity you have to manage yourself.
Asking for an unsupported length
Fails validation locally with 400 INVALID_PARAM naming
durationSec. Nothing is submitted upstream and no credits are touched.
Models covered on this page
Where these facts come from
- codebase: src/ai/providers/*.ts — every pricing() and paramsSchema
- codebase: src/config/website.tsx — credit pack pricing