> ## Documentation Index
> Fetch the complete documentation index at: https://gccai.heqingsong.uk/llms.txt
> Use this file to discover all available pages before exploring further.

# VEO3 Official Video Generation

>  - Asynchronous processing mode, returns task ID for subsequent queries
- Supports text-to-video and image-to-video (first frame / first & last frame control)
- Supports 720P and 1080P resolution
- Supports 4/6/8 second video duration
- Supports audio track generation
- Supports person generation policy control 

```bash cURL theme={null}
curl --request POST \
  --url https://gccai.heqingsong.uk/v1/videos/generations \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
    "model": "veo3.1-fast-official",
    "prompt": "a golden retriever running on the beach, sunset, cinematic",
    "duration": 8,
    "aspect_ratio": "16:9"
  }'
```

```python Python theme={null}
import requests

url = "https://gccai.heqingsong.uk/v1/videos/generations"

payload = {
    "model": "veo3.1-fast-official",
    "prompt": "a golden retriever running on the beach, sunset, cinematic",
    "duration": 8,
    "aspect_ratio": "16:9"
}

headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())
```

```javascript JavaScript theme={null}
const url = "https://gccai.heqingsong.uk/v1/videos/generations";

const payload = {
  model: "veo3.1-fast-official",
  prompt: "a golden retriever running on the beach, sunset, cinematic",
  duration: 8,
  aspect_ratio: "16:9"
};

const headers = {
  "Authorization": "Bearer <token>",
  "Content-Type": "application/json"
};

fetch(url, {
  method: "POST",
  headers: headers,
  body: JSON.stringify(payload)
})
  .then(response => response.json())
  .then(data => console.log(data))
  .catch(error => console.error('Error:', error));
```

```go Go theme={null}
package main

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

func main() {
    url := "https://gccai.heqingsong.uk/v1/videos/generations"

    payload := map[string]interface{}{
        "model":        "veo3.1-fast-official",
        "prompt":       "a golden retriever running on the beach, sunset, cinematic",
        "duration":     8,
        "aspect_ratio": "16:9",
    }

    jsonData, _ := json.Marshal(payload)

    req, _ := http.NewRequest("POST", url, bytes.NewBuffer(jsonData))
    req.Header.Set("Authorization", "Bearer <token>")
    req.Header.Set("Content-Type", "application/json")

    client := &http.Client{}
    resp, err := client.Do(req)
    if err != nil {
        panic(err)
    }
    defer resp.Body.Close()

    body, _ := ioutil.ReadAll(resp.Body)
    fmt.Println(string(body))
}
```

```java Java theme={null}
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.net.URI;

public class Main {
    public static void main(String[] args) throws Exception {
        String url = "https://gccai.heqingsong.uk/v1/videos/generations";

        String payload = """
        {
          "model": "veo3.1-fast-official",
          "prompt": "a golden retriever running on the beach, sunset, cinematic",
          "duration": 8,
          "aspect_ratio": "16:9"
        }
        """;

        HttpClient client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
            .uri(URI.create(url))
            .header("Authorization", "Bearer <token>")
            .header("Content-Type", "application/json")
            .POST(HttpRequest.BodyPublishers.ofString(payload))
            .build();

        HttpResponse<String> response = client.send(request,
            HttpResponse.BodyHandlers.ofString());

        System.out.println(response.body());
    }
}
```

```php PHP theme={null}
<?php

$url = "https://gccai.heqingsong.uk/v1/videos/generations";

$payload = [
    "model" => "veo3.1-fast-official",
    "prompt" => "a golden retriever running on the beach, sunset, cinematic",
    "duration" => 8,
    "aspect_ratio" => "16:9"
];

$ch = curl_init($url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($payload));
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
]);

$response = curl_exec($ch);
curl_close($ch);

echo $response;
?>
```

```ruby Ruby theme={null}
require 'net/http'
require 'json'
require 'uri'

url = URI("https://gccai.heqingsong.uk/v1/videos/generations")

payload = {
  model: "veo3.1-fast-official",
  prompt: "a golden retriever running on the beach, sunset, cinematic",
  duration: 8,
  aspect_ratio: "16:9"
}

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = "Bearer <token>"
request["Content-Type"] = "application/json"
request.body = payload.to_json

response = http.request(request)
puts response.body
```

```swift Swift theme={null}
import Foundation

let url = URL(string: "https://gccai.heqingsong.uk/v1/videos/generations")!

let payload: [String: Any] = [
    "model": "veo3.1-fast-official",
    "prompt": "a golden retriever running on the beach, sunset, cinematic",
    "duration": 8,
    "aspect_ratio": "16:9"
]

var request = URLRequest(url: url)
request.httpMethod = "POST"
request.setValue("Bearer <token>", forHTTPHeaderField: "Authorization")
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.httpBody = try? JSONSerialization.data(withJSONObject: payload)

let task = URLSession.shared.dataTask(with: request) { data, response, error in
    if let error = error {
        print("Error: \(error)")
        return
    }

    if let data = data, let responseString = String(data: data, encoding: .utf8) {
        print(responseString)
    }
}

task.resume()
```

```csharp C# theme={null}
using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        var url = "https://gccai.heqingsong.uk/v1/videos/generations";

        var payload = @"{
            ""model"": ""veo3.1-fast-official"",
            ""prompt"": ""a golden retriever running on the beach, sunset, cinematic"",
            ""duration"": 8,
            ""aspect_ratio"": ""16:9""
        }";

        using var client = new HttpClient();
        client.DefaultRequestHeaders.Add("Authorization", "Bearer <token>");

        var content = new StringContent(payload, Encoding.UTF8, "application/json");
        var response = await client.PostAsync(url, content);
        var result = await response.Content.ReadAsStringAsync();

        Console.WriteLine(result);
    }
}
```

```json 200 theme={null}
{
  "code": 200,
  "data": [
    {
      "status": "submitted",
      "task_id": "task_xxxxxxxxxx"
    }
  ]
}
```

```json 400 theme={null}
{
  "error": {
    "code": 400,
    "message": "Invalid request parameters",
    "type": "invalid_request_error"
  }
}
```

```json 401 theme={null}
{
  "error": {
    "code": 401,
    "message": "Authentication failed, please check your API key",
    "type": "authentication_error"
  }
}
```

```json 402 theme={null}
{
  "error": {
    "code": 402,
    "message": "Insufficient account balance, please recharge and try again",
    "type": "payment_required"
  }
}
```

```json 429 theme={null}
{
  "error": {
    "code": 429,
    "message": "Too many requests, please try again later",
    "type": "rate_limit_error"
  }
}
```

```json 500 theme={null}
{
  "error": {
    "code": 500,
    "message": "Internal server error, please try again later",
    "type": "server_error"
  }
}
```

## Authorization

**Authorization** `string` *required*

All API endpoints require Bearer Token authentication

Get your API Key:

Visit the [API Key Management Page](https://gccai.heqingsong.uk/keys) to get your API Key

Add to the request header:

```
Authorization: Bearer YOUR_API_KEY
```

## Request Parameters

**model** `string` *required*

Video generation model name

Available models:

* `veo3.1-fast-official` - Veo 3.1 Official Fast version
* `veo3.1-quality-official` - Veo 3.1 Official High Quality version

**nsfw\_check** `boolean` (default: false)

Whether to run content moderation before submitting the video task.

* `true`: use `omni-moderation-latest` to review prompts and input images
* `false` or omitted: do not send a moderation request, adding no moderation cost or latency (default)

**prompt** `string` *required*

Positive text prompt

Describe scenes, actions, styles, etc. in detail for better generation results. English prompts are recommended.

Example: `"a golden retriever running on the beach, sunset, cinematic"`

**negative\_prompt** `string`

Negative prompt to exclude unwanted content

Example: `"blurry, low quality, watermark, text"`

**duration** `integer` (default: 8)

Video duration in seconds

Recommended values: `4` / `6` / `8`

Default: `8`

**Note:** Must be a pure number (e.g. `8`), do not add quotes, otherwise an error will occur

**aspect\_ratio** `string` (default: 16:9)

Video aspect ratio

Available values:

* `16:9` - Landscape
* `9:16` - Portrait

Default: `16:9`

**resolution** `string` (default: 720p)

Video resolution

Available values:

* `720p` - Standard resolution
* `1080p` - High definition
* `4K` - Ultra high definition

Default: `720p`

**first\_frame\_image** `string`

First frame image URL for image-to-video generation

> [!WARNING]
>
> * Image URL must be publicly accessible without hotlink protection
> * Object storage URLs are recommended over temporary download links

**last\_frame\_image** `string`

Last frame image URL for image-to-video generation

Used with `first_frame_image` to control first and last frames

**seed** `integer`

Random seed for reproducing generation results

Value range: `0` - `4294967295`

**sample\_count** `integer` (default: 1)

Number of samples to generate (1-4), currently recommended to use `1`

Default: `1`

**generate\_audio** `boolean` (default: false)

Whether to generate audio track

**person\_generation** `string` (default: allow\_adult)

Person generation policy

Available values:

* `allow_adult` - Only allow generating adult persons/faces
* `disallow` - Do not allow generating persons or faces

Default: `allow_adult`

**resize\_mode** `string` (default: pad)

Image resize strategy (effective for image-to-video)

Available values:

* `pad` - Padding mode
* `crop` - Cropping mode

Default: `pad`

**enhance\_prompt** `boolean` (default: true)

Whether to enable upstream prompt enhancement

Default: `true`

> [!WARNING]
>
> * This parameter can only be set to `true`. Setting it to `false` will cause a request error
> * If you don't need this parameter, do not include it

## Text-to-Video vs Image-to-Video

The system automatically determines the mode based on whether image parameters are provided: no images for text-to-video, images for image-to-video.

| Parameter | Text-to-Video | Image-to-Video |
| - | - | - |
| `prompt` | Required | Required |
| `first_frame_image` | Not used | Required (at least one) |
| `last_frame_image` | Not used | Optional (last frame) |
| `negative_prompt` | Optional | Optional |
| `duration` | Optional | Optional |
| `aspect_ratio` | Optional | Optional |
| `resolution` | Optional | Optional |
| `seed` | Optional | Optional |
| `generate_audio` | Optional | Optional |
| `person_generation` | Optional | Optional |
| `resize_mode` | Not applicable | Optional |
| `enhance_prompt` | Optional | Optional |

## Response

**code** `integer`

Response status code, 200 on success

**data** `array`

Response data array

**Properties**

**status** `string`

Task status, initially `submitted` upon submission

**task\_id** `string`

Unique task identifier for querying task status and results

## Usage Scenarios

### Scenario 1: Text-to-Video (Basic)

```json theme={null}
{
  "model": "veo3.1-fast-official",
  "prompt": "a golden retriever running on the beach, sunset, cinematic"
}
```

### Scenario 2: Text-to-Video (Full Parameters)

```json theme={null}
{
  "model": "veo3.1-quality-official",
  "prompt": "a cinematic close-up of a ragdoll cat slowly walking through a sunlit living room",
  "negative_prompt": "blurry, low quality, watermark, text",
  "duration": 8,
  "aspect_ratio": "16:9",
  "resolution": "1080p",
  "seed": 12345,
  "generate_audio": true,
  "person_generation": "disallow",
  "enhance_prompt": true
}
```

### Scenario 3: Image-to-Video (Single First Frame)

```json theme={null}
{
  "model": "veo3.1-fast-official",
  "prompt": "the cat slowly walks forward and looks around",
  "first_frame_image": "https://example.com/cat.png",
  "duration": 8,
  "resolution": "720p"
}
```

### Scenario 4: Image-to-Video (First Frame + Last Frame)

```json theme={null}
{
  "model": "veo3.1-quality-official",
  "prompt": "smooth cinematic transition from the first frame to the last frame",
  "first_frame_image": "https://example.com/frame-start.png",
  "last_frame_image": "https://example.com/frame-end.png",
  "duration": 8,
  "resolution": "1080p"
}
```

### Scenario 5: Video with Audio

```json theme={null}
{
  "model": "veo3.1-quality-official",
  "prompt": "a busy coffee shop with people chatting and barista making latte art",
  "duration": 8,
  "generate_audio": true,
  "aspect_ratio": "16:9"
}
```

> [!NOTE]
>
> **Query Task Results**
>
> Video generation is an asynchronous task that returns a `task_id` upon submission. Use the [Get Task Status](https://gccai.heqingsong.uk/en/api-reference/tasks/status.md) endpoint to query generation progress and results.


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