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

# Wan 2.5 Preview Image to Video

Wan 2.5 Preview Image-to-Video model supports generating videos of 5 or 10 seconds based on the initial frame image and text. New audio capabilities: supports automatic dubbing, or you can provide a custom audio file.

<Tip>
  This is an **asynchronous** API; only the **task\_id** will be returned. You should use the **task\_id** to request the [**Task Result API**](/api-reference/model-apis-task-result) to retrieve the video generation results.
</Tip>

## Request Headers

<ParamField header="Content-Type" type="string" required={true}>
  Supports: `application/json`
</ParamField>

<ParamField header="Authorization" type="string" required={true}>
  Bearer authentication format, for example: Bearer \{\{API Key}}.
</ParamField>

## Request Body

<ParamField body="input" type="object" required={true}>
  Basic input information, such as prompts.

  <Expandable title="properties" defaultOpen={true}>
    <ParamField body="prompt" type="string" required={true}>
      Text prompt. Supports both English and Chinese, with a maximum length of 2000 characters, and any excess will be automatically truncated.

      Example value: A small cat running on the grass.
    </ParamField>

    <ParamField body="negative_prompt" type="string" required={false}>
      Negative prompt, used to describe content that should be avoided in the video, allowing for restrictions on the video content.

      Supports both English and Chinese, with a maximum length of 500 characters. Any excess will be automatically truncated.

      Example value: Low resolution, errors, worst quality, low quality, incomplete, extra fingers, disproportionate, etc.
    </ParamField>

    <ParamField body="img_url" type="string" required={true}>
      The URL of the initial frame image used for video generation.

      The URL must be publicly accessible and support HTTP or HTTPS protocols.

      Image restrictions:

      * Image formats: JPEG, JPG, PNG (no support for transparency), BMP, WEBP.
      * Image resolution: The width and height of the image should be within the range of \[360, 2000] pixels.
      * File size: No more than 10MB.
    </ParamField>

    <ParamField body="audio_url" type="string" required={false}>
      URL of the audio file that the model will use to generate the video. See audio settings for usage instructions.

      Audio restrictions:

      * Format: wav, mp3.
      * Duration: 3-30s.
      * File size: No more than 15MB.

      Overflow handling: If the audio length exceeds the duration value (5 seconds or 10 seconds), the first 5 seconds or 10 seconds will be automatically truncated, and the rest will be discarded. If the audio length is shorter than the video duration, the part beyond the audio length will be silent video. For example, if the audio is 3 seconds and the video duration is 5 seconds, the output video will have sound for the first 3 seconds and be silent for the last 2 seconds.
    </ParamField>
  </Expandable>
</ParamField>

<ParamField body="parameters" type="object" required={false}>
  Video processing parameters, such as specifying the output video resolution and duration.

  <Expandable title="properties" defaultOpen={true}>
    <ParamField body="resolution" type="string" required={false}>
      The resolution tier of the generated video. <br />
      Options: `480P`, `720P`, `1080P`. Default value: `1080P`.
    </ParamField>

    <ParamField body="duration" type="integer" required={false}>
      Specifies the duration of the generated video. Supported values: `5` or `10` seconds.

      Default value: `5`.
    </ParamField>

    <ParamField body="prompt_extend" type="bool" required={false}>
      Whether to enable intelligent prompt rewriting. When enabled, a large model is used to intelligently rewrite the input prompt. This significantly improves the generation effect for shorter prompts but increases processing time.

      * `true`: Default value, enable intelligent rewriting.
      * `false`: Do not enable intelligent rewriting.

      Example value: true.
    </ParamField>

    <ParamField body="audio" type="boolean" required={false}>
      Used to control whether to add audio.

      Parameter priority: audio\_url > audio, only takes effect when audio\_url is empty.

      * `true`: Default value, automatically add audio to the video.
      * `false`: Do not add audio, output silent video.

      Example value: true.
    </ParamField>

    <ParamField body="seed" type="integer" required={false}>
      Random seed, used to control the randomness of the model's generated content. The value range is `[0, 2147483647]`.

      If not provided, the algorithm automatically generates a random number as the seed. To maintain relatively stable generated content, you can use the same seed parameter value.

      Example value: 12345.
    </ParamField>
  </Expandable>
</ParamField>

## Response

<ResponseField name="task_id" type="string" required={true}>
  Use the task\_id to request the [Task Result API](/api-reference/model-apis-task-result) to retrieve the generated outputs.
</ResponseField>