Vidu Q4 Preview API: Uncensored Image to Video in 4K

vidu/q4-preview/video-extend

Continue a clip with Vidu Q4 Preview: the last frame of your video opens a new 3 to 16 second segment, and you get back one file with the original and the continuation joined, at 540p, 720p, 1080p, 2k or 4k.

Filtering differs by endpoint: Image to video — Uncensored, Video extension — Uncensored, Reference to video — Light.

From $0.045/s

Run model View API

Send a request

Examples use the selected endpoint’s public parameter definitions. Replace the API key and example media, then send the request from your server.

SDKs & integrations

POSThttps://api.spicyapi.ai/api/v1/jobs/createTask

API authentication

Keep the API key in the server environment variable SPICY_API_KEY. Use Bearer authentication and Content-Type: application/json for JSON requests.

Authorization: Bearer $SPICY_API_KEY

# Generate the idempotency key once; reuse it when retrying after a lost response.
export SPICY_IDEMPOTENCY_KEY="${SPICY_IDEMPOTENCY_KEY:-$(uuidgen)}"
curl -X POST https://api.spicyapi.ai/api/v1/jobs/createTask \
  -H "Authorization: Bearer $SPICY_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $SPICY_IDEMPOTENCY_KEY" \
  -d '{
  "model": "vidu/q4-preview/video-extend",
  "input": {
    "duration_seconds": 5,
    "prompt": "A slow aerial shot drifting over a misty pine forest at sunrise",
    "resolution": "720p",
    "video_url": "https://example.com/reference.mp4"
  }
}'

# Copy data.taskId from the response into TASK_ID, then poll the status.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.spicyapi.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $SPICY_API_KEY"

Generated from this model’s input schema — the same one the API validates every request against.

Input parameters

Place these fields inside the request body’s input object. Names and types match the API. Do not assume a default when none is specified.

video_urlstringRequired

The clip to continue: MP4, MOV or WebM, up to 60 seconds. Its final frame becomes the opening frame of the new segment, so cut it on a clean, sharp frame. The source is not billed.

Default: Not specified
Constraints: minLength:1
format:"uri"
contentMediaType:["video/mp4","video/webm","video/quicktime"]

promptstringRequired

Required, up to 20,000 characters. What happens next: the action that follows, the camera move and the sound. Put spoken lines in double quotes. The opening frame already fixes the subject and the set, so spend the words on motion.

Default: Not specified
Constraints: minLength:1
maxLength:20000

seedintegerOptional

0 to 2147483647. Hold it steady to compare one changed field at a time; drop it for variety.

Default: Not specified
Constraints: minimum:0
maximum:2147483647

enable_prompt_expansionbooleanOptional

Off by default. When on, the model rewrites and expands your prompt before generating; keep it off for literal direction. Does not change the price.

Default: false

generate_audiobooleanOptional

On by default, so the new segment comes with generated sound. Your source keeps its own sound either way; when one side is silent, the joined file is padded with silence. Does not change the price.

Default: true

duration_secondsintegerOptionalAffects price

Length of the new segment: any whole number from 3 to 16. Defaults to 5. Your source is added on top and is not billed.

Default: 5
Constraints: minimum:3
maximum:16

resolutionstringOptionalAffects price

Sharpness of the generated new segment: 540p, 720p, 1080p, 2k or 4k, default 720p. The resolution only sets how sharp the new segment is generated, so match your source’s resolution: a lower setting makes the new part look softer than the original. It sets the price. A 2k or 4k new segment is a 10-bit HEVC file that some browsers cannot play inline when opened on its own.

Default: "720p"
Allowed values: "540p""720p""1080p""2k""4k"

{
  "additionalProperties": false,
  "properties": {
    "duration_seconds": {
      "default": 5,
      "description": "Length of the new segment in seconds, from 3 to 16. The source clip is added on top and is not billed.",
      "maximum": 16,
      "minimum": 3,
      "type": "integer",
      "x-ui": {
        "advanced": false,
        "affects_price": true,
        "order": 70,
        "unit": "s",
        "widget": "slider"
      }
    },
    "enable_prompt_expansion": {
      "default": false,
      "description": "Let the model rewrite and expand your prompt before generating.",
      "type": "boolean",
      "x-ui": {
        "advanced": true,
        "affects_price": false,
        "order": 40,
        "widget": "switch"
      }
    },
    "generate_audio": {
      "default": true,
      "description": "Generate sound for the new segment. The source keeps its own sound either way.",
      "type": "boolean",
      "x-ui": {
        "affects_price": false,
        "order": 60,
        "widget": "switch"
      }
    },
    "prompt": {
      "description": "Describe what happens next: the action that follows, the camera move and the sound. Put spoken lines in double quotes.",
      "maxLength": 20000,
      "minLength": 1,
      "type": "string",
      "x-ui": {
        "order": 100,
        "primary": true,
        "widget": "textarea"
      }
    },
    "resolution": {
      "default": "720p",
      "description": "Resolution of the generated new segment. It sets how sharp the new part is; match your source clip. 2k and 4k segments come back as 10-bit HEVC.",
      "enum": [
        "540p",
        "720p",
        "1080p",
        "2k",
        "4k"
      ],
      "type": "string",
      "x-ui": {
        "advanced": false,
        "affects_price": true,
        "order": 75,
        "widget": "radio"
      }
    },
    "seed": {
      "description": "Random seed. Keep it fixed only for controlled comparisons, not as a frame-identical guarantee.",
      "maximum": 2147483647,
      "minimum": 0,
      "type": "integer",
      "x-ui": {
        "order": 10,
        "widget": "number"
      }
    },
    "video_url": {
      "contentMediaType": [
        "video/mp4",
        "video/webm",
        "video/quicktime"
      ],
      "description": "The clip to continue: MP4, MOV or WebM, up to 60 seconds. Its last frame opens the new segment, and the result is your clip with the new segment joined on.",
      "format": "uri",
      "minLength": 1,
      "type": "string",
      "x-ui": {
        "max_duration_seconds": 60,
        "order": 90,
        "primary": true,
        "widget": "upload"
      }
    }
  },
  "required": [
    "prompt",
    "video_url"
  ],
  "type": "object",
  "x-pricing": {
    "billingMode": "variant_matrix",
    "variantFields": [
      "resolution"
    ]
  }
}

Track the task

HTTP 202 means the task was accepted, not completed. Save the returned taskId and query that task. Do not create another task while waiting for its result.

Accepted response

HTTP/1.1 202 Accepted
Location: /api/v1/jobs/recordInfo?taskId=job_01k3m8x9q2z4v7n5p6r8s0t1w3

{
  "code": 200,
  "msg": "success",
  "request_id": "req_example_create",
  "data": {
    "taskId": "job_01k3m8x9q2z4v7n5p6r8s0t1w3",
    "state": "queued",
    "estimatedCost": "0.750000"
  }
}

The accepted response includes the estimate so your app can show the same amount in task history and billing.

Read the job

curl --get "https://api.spicyapi.ai/api/v1/jobs/recordInfo" \
  --data-urlencode "taskId=$TASK_ID" \
  -H "Authorization: Bearer $SPICY_API_KEY"

Start polling at about 2 seconds and gradually increase the interval. Stop at a terminal state. After a connection failure, query the original taskId. Retry creation only with the original idempotency key and body.

Or let the callback find you

import { verifyWebhook } from "@spicyapi/sdk";

// express.raw keeps the bytes we signed; express.json never matches.
app.post("/hooks/spicy", express.raw({ type: "application/json" }), (req, res) => {
  const { payload } = verifyWebhook({
    rawBody: req.body,
    timestamp: req.header("X-Webhook-Timestamp"),
    signature: req.header("X-Webhook-Signature"),
    payloadVersion: Number(req.header("X-Webhook-Payload-Version")),
    secret: process.env.SPICY_WEBHOOK_SECRET,
  });
  res.status(200).end();
  void handleFinishedTask(payload);
});

Pass callBackUrl when you create the task and the finished record is POSTed to you — no polling loop at all. Every delivery carries X-Webhook-Timestamp, X-Webhook-Signature and X-Webhook-Payload-Version. The signature is a base64 HMAC-SHA256 over taskId.timestamp.sha256(body), so it must be checked against the raw bytes: parsing the JSON and re-serialising it changes them and the check will fail. Failed deliveries are retried, so the same taskId can arrive twice — make the handler idempotent. Answer 2xx first and do the work afterwards; a slow handler is treated as a failed delivery.

Read the result

Consume output only when state is succeeded. On failure, use errorCode, errorMessage and request_id to investigate. Example costs and states do not represent an actual bill.

Completed response example

{
  "code": 200,
  "msg": "success",
  "request_id": "req_example_record",
  "data": {
    "taskId": "job_01k3m8x9q2z4v7n5p6r8s0t1w3",
    "model": "vidu/q4-preview/video-extend",
    "state": "succeeded",
    "output": {
      "assets": [
        {
          "key": "tasks/2026/08/28/job_01k3m8x9q2z4v7n5p6r8s0t1w3/3f7a1c9e5b2d48f0a6c1e3d5b7f9a1c3.mp4",
          "mime": "video/mp4",
          "url": "https://example.r2.cloudflarestorage.com/results/job_01k3m8x9q2z4v7n5p6r8s0t1w3/result.mp4?X-Amz-Signature=SIGNATURE_FROM_RESPONSE",
          "expiresAt": "2026-08-28T12:20:08.000Z"
        }
      ]
    },
    "cost": "0.750000",
    "settled": true,
    "createdAt": "2026-08-28T12:00:00Z",
    "completedAt": "2026-08-28T12:00:30Z"
  }
}

For each available asset, open or download assets[].url directly without an API Authorization header. The signed URL expires at expiresAt; poll the task again to refresh it while the asset remains within its retention period. A pending or unavailable asset has no URL. Treat signed URLs as private.

SDKs & integrations

Use SpicyAPI in your app, terminal, AI assistant or visual workflow. Choose a setup guide below.

SDKs

TypeScript · Python · Go · PHP · Java

CLI

Terminal commands and automation scripts.

MCP

Claude Code · Cursor · Codex

Agent Skill

Reusable instructions for your AI assistant.

n8n

Self-hosted community nodes and importable HTTP Request templates for n8n Cloud.

ComfyUI

Image, video and audio workflows on a node canvas.

More integrations

SillyTavern Telegram / Discord App proxy OpenAI SDK LangChain Vercel AI SDK

Browse ready-to-use workflows

You do not have to write any of the code above. Connect the MCP server once and any agent that speaks MCP — Claude Code, Codex, Cursor, Windsurf, VS Code, Gemini CLI, Cline, LibreChat — can run this model by name, or run it from your shell with a single command.

Say this to your agent

Use vidu/q4-preview/video-extend to make a five-second shot of a neon-lit rooftop at dusk, slow push-in, and save it to ./out/.

The agent looks the model up in the live catalogue, uploads the local file for you, then shows the exact quote and its maximum charge and waits for your confirmation. Nothing is billed until you say yes.

Connect it once

claude mcp add spicyapi -e SPICY_API_KEY=$SPICY_API_KEY \
  -- npx --yes --package=@spicyapi/mcp spicyapi-mcp
npx skills add spicyapi-ai/spicy-skill

The first line gives the agent the tools; the second gives it the Skill — the operating rules for them, so it quotes before it bills, uploads local files instead of pasting bytes, and reads the finished asset URL rather than guessing. Every other client takes the same server through its own config file: see the developer hub.

Or one command in your shell

npx @spicyapi/cli tasks create --model vidu/q4-preview/video-extend \
  --input-json '{"duration_seconds":5,"prompt":"A slow aerial shot drifting over a misty pine forest at sunrise","resolution":"720p","video_url":"https://example.com/reference.mp4"}' \
  --wait

The input is this endpoint’s own schema, same as the examples above. --wait polls until the task is finished and prints it; add --yes to skip the confirmation prompt in CI. Set SPICY_API_KEY first — one key works for the API, the CLI and the MCP server.

Local files

npx @spicyapi/cli files upload ./poster.png
# -> spicy://uploads/01k3m8x9q2z4v7n5p6r8s0t1w3

npx @spicyapi/cli tasks create --model vidu/q4-preview/video-extend \
  --input-json '{"video_url":"spicy://uploads/01k3m8x9q2z4v7n5p6r8s0t1w3"}' \
  --wait

Request bodies take URLs, not bytes. Upload the file first and pass the spicy:// URI it prints — the field name above is this endpoint’s own, straight from its schema. An agent on MCP does this step for you, which is why the sentence further up can name ./poster.png directly. Media already reachable over public HTTPS needs no upload.

How long results are kept

npx @spicyapi/cli tasks create --model vidu/q4-preview/video-extend \
  --input-json '{…}' --retention 1h --wait

npx @spicyapi/cli tasks get $TASK_ID   # read back the retention that applied

--retention only ever shortens the window — 30m, 1h, 7d, or 0 to delete as soon as the task reaches a terminal state. The value that actually applies is the shortest of your request, your account settings and the platform maximum, so read it back from the task record rather than assuming the number you asked for took effect. Passing a longer window than your account allows does nothing.

Use it in ComfyUI

Install the SpicyAPI nodes from ComfyUI Manager or with the command below, then search for Vidu Q4 Preview · Video Extend on the canvas. The node has the same options as this page and shows its price before it runs.

cd ComfyUI/custom_nodes
git clone https://github.com/spicyapi-ai/comfyui-spicyapi

Workflow examples Setup guide Source on GitHub

The embedded panel reads the same schema as this page, so it cannot drift from the API. If your docs need the content to be searchable, read the JSON under /api/embed/models/ and render it yourself.

<iframe src="https://spicyapi.ai/embed/en/models/vidu-q4-preview/api?model=vidu%2Fq4-preview%2Fvideo-extend" width="100%" height="560" loading="lazy" title="Request example" style="border:1px solid rgba(0,0,0,.12)"></iframe>

Open the panel

Workbench

Send a request

API authentication

Input parameters

Track the task

Read the result

SDKs & integrations

Use it in ComfyUI