Vidu Q4

Vidu Q4 generates video from a single first frame or image references, with optional reference audio; check current pricing and availability before submitting.

Quick example

Replace the example image address with your own publicly accessible image URL.

curl https://reapi.ai/api/v1/videos/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "viduq4-preview",
    "first_frame_image": "https://your-cdn.example/first-frame.png",
    "prompt": "The cyclist rides forward as the camera follows slowly.",
    "duration": 5,
    "resolution": "720p",
    "audio": true
  }'

import os
import requests

response = requests.post(
    "https://reapi.ai/api/v1/videos/generations",
    headers={"Authorization": f"Bearer {os.environ['REAPI_API_KEY']}"},
    json={
        "model": "viduq4-preview",
        "first_frame_image": "https://your-cdn.example/first-frame.png",
        "prompt": "The cyclist rides forward as the camera follows slowly.",
        "duration": 5,
        "resolution": "720p",
        "audio": True,
    },
    timeout=60,
)
response.raise_for_status()
print(response.json())

const response = await fetch("https://reapi.ai/api/v1/videos/generations", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.REAPI_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    model: "viduq4-preview",
    first_frame_image: "https://your-cdn.example/first-frame.png",
    prompt: "The cyclist rides forward as the camera follows slowly.",
    duration: 5,
    resolution: "720p",
    audio: true,
  }),
});
if (!response.ok) throw new Error(await response.text());
console.log(await response.json());

package main

import (
    "bytes"
    "encoding/json"
    "fmt"
    "io"
    "net/http"
    "os"
    "time"
)

func main() {
    body, err := json.Marshal(map[string]any{
        "model": "viduq4-preview",
        "first_frame_image": "https://your-cdn.example/first-frame.png",
        "prompt": "The cyclist rides forward as the camera follows slowly.",
        "duration": 5,
        "resolution": "720p",
        "audio": true,
    })
    if err != nil { panic(err) }
    req, err := http.NewRequest("POST",
        "https://reapi.ai/api/v1/videos/generations", bytes.NewReader(body))
    if err != nil { panic(err) }
    req.Header.Set("Authorization", "Bearer " + os.Getenv("REAPI_API_KEY"))
    req.Header.Set("Content-Type", "application/json")
    client := &http.Client{Timeout: 60 * time.Second}
    resp, err := client.Do(req)
    if err != nil { panic(err) }
    defer resp.Body.Close()
    result, err := io.ReadAll(resp.Body)
    if err != nil { panic(err) }
    if resp.StatusCode < 200 || resp.StatusCode >= 300 {
        panic(fmt.Sprintf("HTTP %d: %s", resp.StatusCode, result))
    }
    fmt.Println(string(result))
}

The submission returns an id. Poll GET /api/v1/tasks/{id} until the task is completed or failed; an accepted submission is not a completed video.

Endpoint

POST /api/v1/videos/generations
Authorization: Bearer YOUR_API_KEY
Content-Type: application/json
Accept: application/json

Use the public model ID viduq4-preview. The page slug is vidu-q4; it is not the request's model ID. See authentication and task polling.

Parameters

The table describes the documented model contract. reAPI forwards model parameters and extensions for generation-time validation. Media inputs must use public HTTP(S) URLs; base64 and data: inputs are rejected. Billing also requires a known resolution rate and a positive integer duration before a task can be charged. Acceptance of an extension does not prove that it affected the output.

Images should be PNG, JPEG, JPG, or WEBP and no larger than 50 MB each. Keep URLs accessible throughout generation. Audio format and duration issues can fail during processing after submission is accepted.

The separate reAPI output control bitrate_mode accepts default (preserve the generated file), standard, or high (output encoding presets). Omission uses default. Legacy false maps to default and true maps to standard. This is output processing, not a model-generation parameter.

Modes and examples

Animate a first frame

Use first_frame_image, one first_frame role, or one unlabelled image without reference audio. The prompt is optional; the image establishes the output aspect ratio.

{
  "model": "viduq4-preview",
  "first_frame_image": "https://your-cdn.example/first-frame.png",
  "audio": false
}

Guide a video with references

Use 1–15 reference images and a prompt. To select reference mode with just one image and no audio, label it reference_image. Reference images and audio keep their order within the supplied arrays.

{
  "model": "viduq4-preview",
  "prompt": "The person in reference image 1 speaks using reference audio 1, then turns toward the window.",
  "image_with_roles": [
    {
      "url": "https://your-cdn.example/person.png",
      "role": "reference_image"
    }
  ],
  "audio_urls": ["https://your-cdn.example/line.mp3"],
  "aspect_ratio": "9:16",
  "duration": 8,
  "resolution": "1080p",
  "audio": true
}

Q4 does not document text-only generation or first/last-frame transitions. Two unlabelled images are references, not the start and end of a transition. An explicit first frame mixed with reference material is outside the documented contract. Additional fields are forwarded rather than treated as proof of an additional supported mode.

Pricing dimensions

The bill scales with output duration and resolution. Image-to-video and reference-to-video use the same resolution rate. Audio on/off uses the same rate, and reference image/audio inputs do not add a separate reference fee. See the Vidu Q4 pricing table for current rates.

Bill formula

credits = ceil(per_second_usd × duration_seconds × 1000)

One credit equals $0.001 USD. Each task settles once; a failed task refunds its reserved generation credits. Polling a task does not create another generation. Repeating a submission creates another task even if the request body or Idempotency-Key is repeated.

Output schema

Example completed task:

{
  "id": "task_example",
  "model": "viduq4-preview",
  "status": "completed",
  "created_at": 1792627200,
  "output": {
    "video_urls": ["https://your-cdn.example/generated-video.mp4"]
  },
  "error": null
}

Read URLs from output.video_urls only after status becomes completed. A failed task includes error.code and error.message. Download the result while its link is available; do not assume permanent storage.

Errors

Request errors use { "error": { "code", "message", "request_id" } }. The error catalog is authoritative for the complete list.

Tips

• Use a first frame when its composition should determine the opening shot; use references when images describe subjects or a scene.
• Number subjects and audio references consistently in the prompt. Changing reference order changes what those numbers refer to.
• Start with a short draft to inspect motion and sound, then choose the duration and resolution required for delivery.
• Inspect the generated file when testing optional fields. An accepted request alone cannot confirm their visual or audio effect.

Related

• Vidu Q4 model page
• Vidu Q3 for text-only or first/last-frame workflows
• Task polling
• Error catalog