> ## 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.

# Kling v3 Video Generation

>  - Async processing mode, returns task ID for subsequent queries
- Supports text-to-video, image-to-video (first frame/first-last frame control)
- Supports standard mode (720P), professional mode (1080P), and 4K mode
- Supports video durations from 3 to 15 seconds
- Supports generating videos with audio 

<RequestExample>
  ```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": "kling-v3",
      "prompt": "A golden cat running on a sunlit meadow, slow motion, cinematic quality",
      "mode": "std",
      "duration": 5,
      "aspect_ratio": "16:9"
    }'
  ```

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

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

  payload = {
      "model": "kling-v3",
      "prompt": "A golden cat running on a sunlit meadow, slow motion, cinematic quality",
      "mode": "std",
      "duration": 5,
      "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: "kling-v3",
    prompt: "A golden cat running on a sunlit meadow, slow motion, cinematic quality",
    mode: "std",
    duration: 5,
    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":        "kling-v3",
          "prompt":       "A golden cat running on a sunlit meadow, slow motion, cinematic quality",
          "mode":         "std",
          "duration":     5,
          "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": "kling-v3",
            "prompt": "A golden cat running on a sunlit meadow, slow motion, cinematic quality",
            "mode": "std",
            "duration": 5,
            "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" => "kling-v3",
      "prompt" => "A golden cat running on a sunlit meadow, slow motion, cinematic quality",
      "mode" => "std",
      "duration" => 5,
      "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: "kling-v3",
    prompt: "A golden cat running on a sunlit meadow, slow motion, cinematic quality",
    mode: "std",
    duration: 5,
    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": "kling-v3",
      "prompt": "A golden cat running on a sunlit meadow, slow motion, cinematic quality",
      "mode": "std",
      "duration": 5,
      "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"": ""kling-v3"",
              ""prompt"": ""A golden cat running on a sunlit meadow, slow motion, cinematic quality"",
              ""mode"": ""std"",
              ""duration"": 5,
              ""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);
      }
  }
  ```
</RequestExample>

<ResponseExample>
  ```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": "Invalid authentication credentials",
      "type": "authentication_error"
    }
  }
  ```

  ```json 402 theme={null}
  {
    "error": {
      "code": 402,
      "message": "Insufficient balance. Please top up your account",
      "type": "payment_required"
    }
  }
  ```

  ```json 429 theme={null}
  {
    "error": {
      "code": 429,
      "message": "Rate limit exceeded. 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"
    }
  }
  ```
</ResponseExample>

## Authorization

<ParamField header="Authorization" type="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 it to the request header:

  ```
  Authorization: Bearer YOUR_API_KEY
  ```
</ParamField>

## Request Parameters

<ParamField body="model" type="string" required>
  Video generation model name

  Supported models:

  * `kling-v3` - Kling v3 (recommended)
</ParamField>

<ParamField body="prompt" type="string" required>
  Text prompt

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

  Example: `"a golden retriever running on the beach, sunset, cinematic"`
</ParamField>

<ParamField body="negative_prompt" type="string">
  Negative prompt to exclude unwanted content

  Example: `"blurry, low quality, distorted"`
</ParamField>

<ParamField body="mode" type="string" default="std">
  Generation mode

  Options:

  * `std` - Standard mode (720P)
  * `pro` - Professional mode (1080P)
  * `4k` - 4K mode

  Default: `std`
</ParamField>

<ParamField body="duration" type="integer" default="5">
  Default: `5`
  Video duration (seconds)

  Range: 3-15 (minimum 3 seconds, maximum 15 seconds)

  **⚠️ Note:** Must be a plain number (e.g. `6`), do not add quotes, otherwise an error will occur
</ParamField>

<ParamField body="aspect_ratio" type="string" default="16:9">
  Video aspect ratio

  Options:

  * `16:9` - Landscape
  * `9:16` - Portrait
  * `1:1` - Square

  Default: `16:9`
</ParamField>

<ParamField body="image_urls" type="array<url>">
  Image URL array for image-to-video generation

  * Pass **1 image**: used as first frame
  * Pass **2 images**: automatically assigned as first frame + last frame

  Maximum 2 images supported

  Example: `["https://example.com/first.jpg"]`

  <Warning>
    * Maximum 2 images supported
    * Image URLs must be publicly accessible without hotlink protection
    * In image-to-video mode, `aspect_ratio` may be overridden by the actual image ratio
  </Warning>
</ParamField>

<ParamField body="watermark" type="boolean">
  Whether to add watermark
</ParamField>

<ParamField body="audio" type="boolean" default="false">
  Whether to generate video with audio
</ParamField>

<ParamField body="multi_shot" type="boolean" default="false">
  Whether to enable multi-shot mode.

  * `true`
  * `false`
</ParamField>

<ParamField body="shot_type" type="string">
  Shot split method: `customize` / `intelligence`.

  Required when `multi_shot=true`.
</ParamField>

<ParamField body="multi_prompt" type="array<object>">
  Per-shot information, such as prompt and duration.

  Define shot order, prompt, and duration via `index`, `prompt`, and `duration`.

  * Supports 1 to 6 shots
  * Maximum content length per shot is 512
  * Each shot duration must be >= 1 and cannot exceed total task duration
  * Sum of all shot durations must equal top-level `duration`

  Format:

  ```json theme={null}
  "multi_prompt": [
    { "index": 1, "prompt": "string", "duration": 5 },
    { "index": 2, "prompt": "string", "duration": 5 }
  ]
  ```

  Required when `multi_shot=true` and `shot_type=customize`.
</ParamField>

<ParamField body="element_list" type="array<object>">
  Reference subject list, up to 3 subjects.

  * Create on the fly via `name`, `description`, `element_input_urls`

  Example:

  ```json theme={null}
  [
    {
      "name": "element_dog",
      "description": "a golden retriever, fluffy fur, friendly expression",
      "element_input_urls": [
        "https://example.com/image1.png",
        "https://example.com/image2.png"
      ]
    },
    {
      "name": "element_cat",
      "description": "an orange tabby cat, round face, bright eyes",
      "element_input_urls": [
        "https://example.com/image1.png",
        "https://example.com/image2.png"
      ]
    }
  ]
  ```

  Notes:

  * `name`, `description`, and `element_input_urls` are required for on-the-fly creation
  * `element_input_urls`: 2-4 images per subject (first as frontal image, rest as references)
  * Reference elements in `prompt` with `@name`, e.g. `"@element_dog chasing @element_cat on grass"`
</ParamField>

### Parameter Constraints

* `mode=4k` is supported for `kling-v3`
* `image_urls` supports up to 2 images (1 first frame, 2 first+last frames)
* Last-frame-only input is invalid (must include first frame)
* When `multi_shot=true`, top-level `prompt` can be omitted
* `multi_prompt` supports up to 6 shots, and `index` must start from 1 and be continuous

## Feature Support Matrix

| Type           | Feature     | std 5s | std 10s | std 15s | pro 5s | pro 10s |
| -------------- | ----------- | ------ | ------- | ------- | ------ | ------- |
| Text-to-Video  | Generation  | ✅      | ✅       | ✅       | ✅      | ✅       |
| Image-to-Video | Generation  | ✅      | ✅       | ✅       | ✅      | ✅       |
| Image-to-Video | First Frame | ✅      | ✅       | ✅       | ✅      | ✅       |
| Image-to-Video | Last Frame  | ✅      | ✅       | ✅       | ✅      | ✅       |

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

The system automatically determines the mode based on whether `image_urls` is provided: no images means text-to-video, with images means image-to-video.

| Parameter         | Text-to-Video     | Image-to-Video                      |
| ----------------- | ----------------- | ----------------------------------- |
| `prompt`          | ✅ Required        | ✅ Required                          |
| `image_urls`      | ❌ Not used        | ✅ Required (1-2 images)             |
| `negative_prompt` | ✅ Optional        | ✅ Optional                          |
| `mode`            | ✅ Optional        | ✅ Optional                          |
| `duration`        | ✅ Optional (3-15) | ✅ Optional (3-15)                   |
| `aspect_ratio`    | ✅ Optional        | ⚠️ May be overridden by image ratio |
| `watermark`       | ✅ Optional        | ✅ Optional                          |
| `audio`           | ✅ Optional        | ✅ Optional                          |

## Response

<ResponseField name="code" type="integer">
  Response status code, 200 on success
</ResponseField>

<ResponseField name="data" type="array">
  Response data array

  <Expandable title="Array Elements">
    <ResponseField name="status" type="string">
      Task status, `submitted` when initially submitted
    </ResponseField>

    <ResponseField name="task_id" type="string">
      Unique task identifier for querying task status and results
    </ResponseField>
  </Expandable>
</ResponseField>

## Use Cases

### Case 1: Text-to-Video (Standard Mode)

```json theme={null}
{
  "model": "kling-v3",
  "prompt": "A golden cat running on a sunlit meadow, slow motion, cinematic quality",
  "mode": "std",
  "duration": 5,
  "aspect_ratio": "16:9"
}
```

### Case 2: Text-to-Video (Pro Mode + Negative Prompt)

```json theme={null}
{
  "model": "kling-v3",
  "prompt": "Tokyo Shibuya crossing at night, neon lights reflected on wet ground, people walking with umbrellas",
  "negative_prompt": "blurry, low quality, distorted",
  "mode": "pro",
  "duration": 10,
  "aspect_ratio": "16:9"
}
```

### Case 3: Text-to-Video (15 seconds)

```json theme={null}
{
  "model": "kling-v3",
  "prompt": "a time-lapse of a flower blooming in a garden",
  "duration": 15,
  "aspect_ratio": "16:9"
}
```

### Case 4: Image-to-Video (First Frame)

```json theme={null}
{
  "model": "kling-v3",
  "prompt": "the cat slowly walks forward and looks around",
  "image_urls": ["https://example.com/cat.jpg"],
  "mode": "std",
  "duration": 5
}
```

### Case 5: Image-to-Video (First + Last Frame Control)

```json theme={null}
{
  "model": "kling-v3",
  "prompt": "smooth cinematic transition",
  "image_urls": [
    "https://example.com/frame-start.jpg",
    "https://example.com/frame-end.jpg"
  ],
  "mode": "std",
  "duration": 5
}
```

### Case 6: Generate Video with Audio

```json theme={null}
{
  "model": "kling-v3",
  "prompt": "A rock singer singing on this stage, concert scene, flashing lights",
  "audio": true,
  "mode": "std",
  "duration": 5
}
```

### Case 7: Multi-Shot Storyboard (`customize`, 15 seconds, portrait with audio)

```json theme={null}
{
  "model": "kling-v3",
  "multi_prompt": [
    {
      "index": 1,
      "prompt": "Two friends talking under a streetlight at night. Warm glow, casual poses, no dialogue.",
      "duration": 2
    },
    {
      "index": 2,
      "prompt": "A runner sprinting through a forest, leaves flying. Low-angle shot, focus on movement.",
      "duration": 3
    },
    {
      "index": 3,
      "prompt": "A woman hugging a cat, smiling. Soft sunlight, cozy home setting, emphasize warmth.",
      "duration": 3
    },
    {
      "index": 4,
      "prompt": "A door creaking open, shadowy hallway. Dark tones, minimal details, eerie mood.",
      "duration": 3
    },
    {
      "index": 5,
      "prompt": "A man slipping on a banana peel, shocked expression. Exaggerated pose, bright colors.",
      "duration": 3
    },
    {
      "index": 6,
      "prompt": "A sunset over mountains, small figure walking away. Wide angle, peaceful atmosphere.",
      "duration": 1
    }
  ],
  "multi_shot": true,
  "shot_type": "customize",
  "duration": 15,
  "mode": "pro",
  "audio": true,
  "aspect_ratio": "9:16"
}
```

<Note>
  **Query Task Results**

  Video generation is an async task that returns a `task_id` upon submission. Use the [Get Task Status](/en/api-reference/tasks/status) endpoint to query generation progress and results.
</Note>