black-forest-labs/flux-3/video-extend-draft
black-forest-labs/flux-3/video-extend-draft
FLUX 3 Video Extend Draft quickly continues a required input video into a draft clip with prompt-guided next-scene motion, optional synchronized audio, and flexible 5-20 second duration for rapid iteration.
Examples
Parameters
| Name | Type | Default | Constraints | Description |
|---|---|---|---|---|
| prompt *Prompt | textarea | — | ≤ 5000 chars | The text prompt describing the video you want to generate. |
| aspect_ratioAspect Ratio | select | — | 21:9 | 2:1 | 16:9 | 4:3 | 1:1 | 3:4 | 9:16 | The aspect ratio of the generated media. |
| durationDuration | slider | 5 | 5 ~ 20 · step 1 | Video length in seconds (5-20). |
| generate_audioGenerate Audio | boolean | true | — | Whether to generate audio for the video. |
Output fields
| Field | Type | Description |
|---|---|---|
| videos | array<string> |
API
Call this model through one unified REST API. Get a key on the API Keys page.
cURL
# 1) Submit — returns { "task_uuid": "..." }
curl -X POST "https://www.namifusion.com/api/v1/marketplace/run/black-forest-labs/flux-3/video-extend-draft" \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"input": {
"prompt": "Continue the scene naturally, preserving the subjects, setting, lighting and motion of the input video.",
"aspect_ratio": "16:9",
"duration": 5,
"generate_audio": true
}
}'
# 2) Poll until status is "completed", then read the output URLs
curl "https://www.namifusion.com/api/v1/marketplace/run/tasks/TASK_UUID" \
-H "Authorization: Bearer YOUR_API_KEY"Python
import time, requests
API_KEY = "YOUR_API_KEY"
HEADERS = {"Authorization": f"Bearer {API_KEY}"}
# 1) Submit
resp = requests.post(
"https://www.namifusion.com/api/v1/marketplace/run/black-forest-labs/flux-3/video-extend-draft",
headers=HEADERS,
json={
"input": {
"prompt": "Continue the scene naturally, preserving the subjects, setting, lighting and motion of the input video.",
"aspect_ratio": "16:9",
"duration": 5,
"generate_audio": True
}
},
)
resp.raise_for_status() # 401/402/429/5xx stop here instead of polling a bad task
task = resp.json()
# 2) Poll until a terminal state (completed / failed / cancelled).
# This model is allowed up to 1800s server-side.
deadline = time.time() + 1860
while task.get("status") not in ("completed", "failed", "cancelled"):
if time.time() > deadline:
raise TimeoutError(f"still {task.get('status')} — keep the task_uuid and poll later")
time.sleep(3)
poll = requests.get(f"https://www.namifusion.com/api/v1/marketplace/run/tasks/{task['task_uuid']}", headers=HEADERS)
poll.raise_for_status()
task = poll.json()
print(task["status"], task.get("output"))JavaScript
const API_KEY = "YOUR_API_KEY";
const HEADERS = { Authorization: `Bearer ${API_KEY}` };
// 1) Submit
const resp = await fetch("https://www.namifusion.com/api/v1/marketplace/run/black-forest-labs/flux-3/video-extend-draft", {
method: "POST",
headers: { ...HEADERS, "Content-Type": "application/json" },
body: JSON.stringify({
"input": {
"prompt": "Continue the scene naturally, preserving the subjects, setting, lighting and motion of the input video.",
"aspect_ratio": "16:9",
"duration": 5,
"generate_audio": true
}
}),
});
if (!resp.ok) throw new Error(`submit failed: ${resp.status} ${await resp.text()}`);
let task = await resp.json();
// 2) Poll until a terminal state (completed / failed / cancelled).
// This model is allowed up to 1800s server-side.
const deadline = Date.now() + 1860 * 1000;
while (!["completed", "failed", "cancelled"].includes(task.status)) {
if (Date.now() > deadline) throw new Error(`still ${task.status} — keep the task_uuid and poll later`);
await new Promise((r) => setTimeout(r, 3000));
const poll = await fetch(`https://www.namifusion.com/api/v1/marketplace/run/tasks/${task.task_uuid}`, { headers: HEADERS });
if (!poll.ok) throw new Error(`poll failed: ${poll.status}`);
task = await poll.json();
}
console.log(task.status, task.output);Documentation
black-forest-labs/flux-3/video-extend-draft
black-forest-labs/flux-3/video-extend-draft
FLUX 3 Video Extend Draft quickly continues a required input video into a draft clip with prompt-guided next-scene motion, optional synchronized audio, and flexible 5-20 second duration for rapid iteration.
Parameters
| Parameter | Type | Required | Default | Limits / description |
|---|---|---|---|---|
prompt | string | Yes | — | max 5000 chars; The text prompt describing the video you want to generate. |
video | string | Yes | — | URL of the input video. MP4, under 50 MB and under 15 seconds. |
aspect_ratio | string | No | — | 21:9, 2:1, 16:9, 4:3, 1:1, 3:4, 9:16; The aspect ratio of the generated media. |
duration | integer | No | 5 | 5–20; step 1; Video length in seconds (5-20). |
generate_audio | boolean | No | true | Whether to generate audio for the video. |
Pricing
| Mode | USD / second | Credits / second | USD / 5 seconds |
|---|---|---|---|
| Draft | $0.12 | 12 | $0.6 |
Price = rate × min(ceil(duration), 20). duration is an integer from 5 to 20; default 5. generate_audio does not change the price. Billing uses requested extension duration, not the input video duration.
WaveSpeed standard list price; USD 1 = 100 credits. Account discounts are separate.
API
curl -X POST https://www.namifusion.com/api/v1/marketplace/run/black-forest-labs/flux-3/video-extend-draft \
-H "Authorization: Bearer $API_KEY" \
-H 'Content-Type: application/json' \
-d '{
"input": {
"prompt": "Continue the scene naturally, preserving the subjects, setting, lighting and motion of the input video.",
"video": "https://assets-public.namifusion.com/marketplace/videos/2026-04-14/88d6efad3763.mp4",
"aspect_ratio": "16:9",
"duration": 5,
"generate_audio": true
}
}'
curl 'https://www.namifusion.com/api/v1/marketplace/run/tasks/TASK_UUID' \
-H "Authorization: Bearer $API_KEY"
Submit returns task_uuid. Poll until completed or failed. Successful output: output.videos (URL array). This API is asynchronous and returns URLs.
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