# Vidu Q4 (`vidu_q4`)

> Vidu Q4. Video with native audio from a first frame, or from reference images and voice clips; 3-16 seconds, 540p to 4K. No text-only mode.

- Capability: Video (tool `video`) — Image to video, Text to video
- Price: from $0.14 per run (1 credit = $0.01). Exact price for a request: POST https://api.varg.ai/v2/estimate
- Typical time: ~2 min
- JSON Schema: https://api.varg.ai/v2/tools/video?model=vidu_q4 (public, no key)
- Try it: https://varg.ai/dashboard/tools/playground?model=vidu_q4

## Call it

REST: `POST https://api.varg.ai/v2/tools/video/call` with `Authorization: Bearer $VARG_API_KEY` (create a key at https://varg.ai/dashboard/api).
It answers `202` with a job right away. Poll `GET /v2/jobs/{id}` until `status` is `completed`, then read `output.outputs[0].url` — or pass `options.webhook_url` and get the finished job POSTed to you.

```bash
curl -X POST https://api.varg.ai/v2/tools/video/call \
  -H "Authorization: Bearer $VARG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "vidu_q4",
  "prompt": "The woman turns toward the camera and smiles, then the shot cuts to a close-up as she says: \"Let'\''s go.\"",
  "files": [
    {
      "url": "https://storage.googleapis.com/falserverless/web-examples/vidu/stylish_woman.webp"
    }
  ],
  "resolution": "720p",
  "duration": 5
}'
```

MCP: the varg server `https://mcp.varg.ai/mcp` (OAuth sign-in, no key) runs it with `call_tool`:

```json
{
  "tool": "video",
  "input": {
    "model": "vidu_q4",
    "prompt": "The woman turns toward the camera and smiles, then the shot cuts to a close-up as she says: \"Let's go.\"",
    "files": [
      {
        "url": "https://storage.googleapis.com/falserverless/web-examples/vidu/stylish_woman.webp"
      }
    ],
    "resolution": "720p",
    "duration": 5
  },
  "wait": true
}
```

## Inputs

| field | type | required | default | allowed | description |
|---|---|---|---|---|---|
| `model` | string | yes | — | `vidu_q4` or a route key below | Which model runs the job. |
| `prompt` | string | no | — | — | — |
| `files` | array of { url } | no | — | — | — |
| `aspect_ratio` | string | no | — | e.g. 16:9 \| 9:16 \| 1:1 \| 4:3 \| 3:4 \| 21:9 \| auto | — |
| `resolution` | string | no | — | 480p \| 720p \| 1080p \| 4k | Quality tier. Supported by this model: 480p, 720p, 1080p, 4k. Unsupported tiers fall back to the nearest available. |
| `audio` | boolean | no | — | — | Set true to generate the video with a native audio track. |
| `duration` | integer | no | — | 3–16 | Length in seconds. Supported by this model's routes: fal: integer 3-16. A non-numeric value such as "auto" is routed to a route whose schema accepts it; when none does, the request is rejected. |

Media inputs are URLs. Upload a local file first with `POST /v2/files` and pass the returned URL.

## Provider options

Optional, per provider, under `provider_options.<provider>`. Only the options of the provider that runs the job apply — pin a route to choose it.

### provider_options.fal

| field | type | required | default | allowed | description |
|---|---|---|---|---|---|
| `prompt` | string | no | — | — | Text prompt for video generation, max 5000 characters |
| `reference_audio_urls` | array of URL strings | no | — | — | — |
| `reference_image_urls` | array of URL strings | no | — | — | — |
| `duration` | integer | no | — | 3–16 | Duration of the video in seconds (3-16) |
| `image_url` | string (URL) | no | — | — | URL or base64 data URI of the image to use as the first frame. Supports png, jpeg, jpg and webp up to 50 MB. |
| `resolution` | string | no | — | 540p \| 720p \| 1080p \| 2K \| 4K | — |
| `audio` | boolean | no | — | — | Whether to generate audio (dialogue and sound effects) with the video. When false, the output video is silent. |
| `aspect_ratio` | string | no | — | 16:9 \| 9:16 \| 4:3 \| 3:4 \| 1:1 | — |

## Routes

`"model": "vidu_q4"` picks a route automatically (priority order, then the inputs you send). To pin one, pass its key as `model`.

| model key | provider | modality | price from | typical time |
|---|---|---|---|---|
| `fal:fal-ai/vidu/q4/image-to-video` | fal | image-to-video | $0.14 | ~2 min |
| `fal:fal-ai/vidu/q4/reference-to-video` | fal | text-to-video, image-to-video | $0.14 | ~2 min |

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Catalog version 2026-11-11T12:59:09.901887+00:00. All models: https://varg.ai/models/llms.txt