How to call the Wan image-to-video model using first and last frames-Alibaba Cloud Model Studio(Model Studio)-阿里云帮助中心

Core capabilities: Fixed 5-second duration, custom resolution (480P/720P/1080P), prompt rewriting, and watermarking.
Video effect templates: Upload only the first-frame image and select an effect template to generate a video with a specific dynamic effect.

Quick links: API reference | Prompt guide | Video effect list

Getting started

Prompt

First frame

Last frame

Output video

A cute blue monster with a slightly sad expression stands in the rain. The camera slowly zooms in and stops on the moment it looks up at the sky.

Before calling the API: Get an API key, set it as an environment variable, and install the DashScope SDK.

Python SDK

Important

Requires DashScope Python SDK ≥ 1.25.8 before running the code below. Older versions may show "url error, please check url!" errors. Install the SDK.

import os
from http import HTTPStatus
from dashscope import VideoSynthesis
import dashscope

# This URL is for the Beijing region. URLs differ by region. Get your region's URL: https://help.aliyun.com/en/model-studio/image-to-video-by-first-and-last-frame-api-reference
dashscope.base_http_api_url = 'https://dashscope.aliyuncs.com/api/v1'
# API keys differ by region. Get your API key: https://help.aliyun.com/en/model-studio/get-api-key
api_key = os.getenv("DASHSCOPE_API_KEY", "YOUR_API_KEY")

print('please wait...')
rsp = VideoSynthesis.call(api_key=api_key,
                          model="wan2.2-kf2v-flash",
                          prompt="A cute blue monster with a slightly sad expression stands in the rain. The camera slowly zooms in and stops on the moment it looks up at the sky.",
                          first_frame_url="https://help-static-aliyun-doc.aliyuncs.com/file-manage-files/zh-CN/20260126/ixdxvt/wan-kf2v-blue-1.png",
                          last_frame_url="https://help-static-aliyun-doc.aliyuncs.com/file-manage-files/zh-CN/20260126/nhtdrc/wan-kf2v-blue-2.png",
                          duration=5,  # Fixed at 5 seconds. Do not change.
                          resolution="720P",
                          prompt_extend=True,
                          watermark=True)
print(rsp)
if rsp.status_code == HTTPStatus.OK:
    print("video_url:", rsp.output.video_url)
else:
    print('Failed, status_code: %s, code: %s, message: %s' % (rsp.status_code, rsp.code, rsp.message))

Java SDK

Important

Requires DashScope Java SDK ≥ 2.22.6 before running the code below. Older versions may show "url error, please check url!" errors. Install the SDK.

import com.alibaba.dashscope.aigc.videosynthesis.VideoSynthesis;
import com.alibaba.dashscope.aigc.videosynthesis.VideoSynthesisParam;
import com.alibaba.dashscope.aigc.videosynthesis.VideoSynthesisResult;
import com.alibaba.dashscope.exception.ApiException;
import com.alibaba.dashscope.exception.InputRequiredException;
import com.alibaba.dashscope.exception.NoApiKeyException;
import com.alibaba.dashscope.utils.JsonUtils;
import com.alibaba.dashscope.utils.Constants;

public class Image2Video {

    static {
        // This URL is for the China (Beijing) region. URLs differ by region. Get your URL: https://help.aliyun.com/en/model-studio/image-to-video-by-first-and-last-frame-api-reference
        Constants.baseHttpApiUrl = "https://dashscope.aliyuncs.com/api/v1";
    }

    // If you have not set an environment variable, replace the line below with: apiKey="sk-xxx"
    // API keys differ by region. Get your API key: https://help.aliyun.com/en/model-studio/get-api-key
    static String apiKey = System.getenv("DASHSCOPE_API_KEY");

    public static void image2video() throws ApiException, NoApiKeyException, InputRequiredException {
        VideoSynthesis vs = new VideoSynthesis();
        VideoSynthesisParam param =
                VideoSynthesisParam.builder()
                        .apiKey(apiKey)
                        .model("wan2.2-kf2v-flash")
                        .prompt("A cute blue monster with a slightly sad expression stands in the rain. The camera slowly zooms in and stops on the moment it looks up at the sky.")
                        .firstFrameUrl("https://help-static-aliyun-doc.aliyuncs.com/file-manage-files/zh-CN/20260126/ixdxvt/wan-kf2v-blue-1.png")
                        .lastFrameUrl("https://help-static-aliyun-doc.aliyuncs.com/file-manage-files/zh-CN/20260126/nhtdrc/wan-kf2v-blue-2.png")
                        .resolution("720P")
                        .promptExtend(true)
                        .watermark(true)
                        .build();
        System.out.println("please wait...");
        VideoSynthesisResult result = vs.call(param);
        System.out.println(JsonUtils.toJson(result));
    }

    public static void main(String[] args) {
        try {
            image2video();
        } catch (ApiException | NoApiKeyException | InputRequiredException e) {
            System.out.println(e.getMessage());
        }
        System.exit(0);
    }
}

curl

Step 1: Create a task to get the task ID

curl --location 'https://dashscope.aliyuncs.com/api/v1/services/aigc/image2video/video-synthesis' \
    -H 'X-DashScope-Async: enable' \
    -H "Authorization: Bearer $DASHSCOPE_API_KEY" \
    -H 'Content-Type: application/json' \
    -d '{
    "model": "wan2.2-kf2v-flash",
    "input": {
        "first_frame_url": "https://help-static-aliyun-doc.aliyuncs.com/file-manage-files/zh-CN/20260126/ixdxvt/wan-kf2v-blue-1.png",
        "last_frame_url": "https://help-static-aliyun-doc.aliyuncs.com/file-manage-files/zh-CN/20260126/nhtdrc/wan-kf2v-blue-2.png",
        "prompt": "A cute blue monster with a slightly sad expression stands in the rain. The camera slowly zooms in and stops on the moment it looks up at the sky."
    },
    "parameters": {
        "resolution": "720P",
        "prompt_extend": true,
        "watermark": true
    }
}'

Step 2: Get the result using the task ID

Replace {task_id} with the task_id value returned by the previous API call. The task_id is valid for queries for 24 hours.

curl -X GET https://dashscope.aliyuncs.com/api/v1/tasks/{task_id} \
--header "Authorization: Bearer $DASHSCOPE_API_KEY"

Sample output

video_url expires after 24 hours. Download the video promptly.

{
    "request_id": "c1209113-8437-424f-a386-xxxxxx",
    "output": {
        "task_id": "966cebcd-dedc-4962-af88-xxxxxx",
        "task_status": "SUCCEEDED",
        "video_url": "https://dashscope-result-sh.oss-accelerate.aliyuncs.com/xxx.mp4?Expires=xxx",
         ...
    },
    ...
}

Availability

Supported models vary by region. Resources are isolated between regions. For supported models in each region, see the Model Studio console.
When making a call, make sure your model, endpoint URL, and API key all belong to the same region. Cross-region calls fail.

Note

Sample codes in this topic apply to the Beijing region.

Core capabilities

Generate video from first and last frames

Supported models: All models.

Generates smooth videos from first-frame and last-frame images.

Parameters:

first_frame_url: Required. Provide the first-frame image.
last_frame_url: Required. Provide the last-frame image.
prompt: Optional (recommended). Controls how the video changes over time.

Prompt

First frame

Last frame

Output video

Realistic style. A curious black kitten looks up at the sky. The camera starts at eye level and gradually rises until it captures the kitten’s curious gaze from above.

首帧图像

尾帧图像

Python SDK

Requires DashScope Python SDK ≥ 1.25.8. Upgrade if needed.

import os
from http import HTTPStatus
from dashscope import VideoSynthesis
import dashscope

# This URL is for the Beijing region. URLs differ by region. Get your region's URL: https://help.aliyun.com/en/model-studio/image-to-video-api-reference
dashscope.base_http_api_url = 'https://dashscope.aliyuncs.com/api/v1'

# If you have not set an environment variable, replace the line below with: api_key="sk-xxx"
# API keys differ by region. Get your API key: https://help.aliyun.com/en/model-studio/get-api-key
api_key = os.getenv("DASHSCOPE_API_KEY")

def sample_async_call_kf2v():
    # Asynchronous call returns a task_id
    rsp = VideoSynthesis.async_call(api_key=api_key,
                                    model="wan2.2-kf2v-flash",
                                    prompt="Realistic style. A curious black kitten looks up at the sky. The camera starts at eye level and gradually rises until it captures the kitten’s curious gaze from above.",
                                    first_frame_url="https://wanx.alicdn.com/material/20250318/first_frame.png",
                                    last_frame_url="https://wanx.alicdn.com/material/20250318/last_frame.png",
                                    duration=5,  # Fixed at 5 seconds. Do not change.
                                    prompt_extend=True,
                                    watermark=True)
    print(rsp)
    if rsp.status_code == HTTPStatus.OK:
        print("task_id: %s" % rsp.output.task_id)
    else:
        print('Failed, status_code: %s, code: %s, message: %s' % (rsp.status_code, rsp.code, rsp.message))

    # Wait for asynchronous task to complete
    rsp = VideoSynthesis.wait(task=rsp, api_key=api_key)
    print(rsp)
    if rsp.status_code == HTTPStatus.OK:
        print(rsp.output.video_url)
    else:
        print('Failed, status_code: %s, code: %s, message: %s' % (rsp.status_code, rsp.code, rsp.message))


if __name__ == '__main__':
    sample_async_call_kf2v()

Java SDK

Requires DashScope Java SDK ≥ 2.22.6. Upgrade if needed.

import com.alibaba.dashscope.aigc.videosynthesis.VideoSynthesis;
import com.alibaba.dashscope.aigc.videosynthesis.VideoSynthesisParam;
import com.alibaba.dashscope.aigc.videosynthesis.VideoSynthesisResult;
import com.alibaba.dashscope.exception.ApiException;
import com.alibaba.dashscope.exception.InputRequiredException;
import com.alibaba.dashscope.exception.NoApiKeyException;
import com.alibaba.dashscope.utils.JsonUtils;
import com.alibaba.dashscope.utils.Constants;

public class Image2Video {

    static {
        // This URL is for the Beijing region. URLs differ by region. Get your region's URL: https://help.aliyun.com/en/model-studio/image-to-video-by-first-and-last-frame-api-reference
        Constants.baseHttpApiUrl = "https://dashscope.aliyuncs.com/api/v1";
    }

    // If you have not set an environment variable, replace the line below with: apiKey="sk-xxx"
    // API keys differ by region. Get your API key: https://help.aliyun.com/en/model-studio/get-api-key
    static String apiKey = System.getenv("DASHSCOPE_API_KEY");

    public static void image2video() throws ApiException, NoApiKeyException, InputRequiredException {
        VideoSynthesis vs = new VideoSynthesis();
        VideoSynthesisParam param =
                VideoSynthesisParam.builder()
                        .apiKey(apiKey)
                        .model("wan2.2-kf2v-flash")
                        .prompt("Realistic style. A curious black kitten looks up at the sky. The camera starts at eye level and gradually rises until it captures the kitten's curious gaze from above.")
                        .firstFrameUrl("https://wanx.alicdn.com/material/20250318/first_frame.png")
                        .lastFrameUrl("https://wanx.alicdn.com/material/20250318/last_frame.png")
                        .resolution("720P")
                        .promptExtend(true)
                        .watermark(true)
                        .build();
        // Asynchronous call
        VideoSynthesisResult task = vs.asyncCall(param);
        System.out.println(JsonUtils.toJson(task));
        System.out.println("please wait...");

        // Get result
        VideoSynthesisResult result = vs.wait(task, apiKey);
        System.out.println(JsonUtils.toJson(result));
    }

    public static void main(String[] args) {
        try {
            image2video();
        } catch (ApiException | NoApiKeyException | InputRequiredException e) {
            System.out.println(e.getMessage());
        }
        System.exit(0);
    }
}

curl

Step 1: Create a task to get the task ID

curl --location 'https://dashscope.aliyuncs.com/api/v1/services/aigc/image2video/video-synthesis' \
    -H 'X-DashScope-Async: enable' \
    -H "Authorization: Bearer $DASHSCOPE_API_KEY" \
    -H 'Content-Type: application/json' \
    -d '{
    "model": "wan2.2-kf2v-flash",
    "input": {
        "first_frame_url": "https://wanx.alicdn.com/material/20250318/first_frame.png",
        "last_frame_url": "https://wanx.alicdn.com/material/20250318/last_frame.png",
        "prompt": "Realistic style. A curious black kitten looks up at the sky. The camera starts at eye level and gradually rises until it captures the kitten’s curious gaze from above."
    },
    "parameters": {
        "resolution": "720P",
        "prompt_extend": true,
        "watermark": true
    }
}'

Step 2: Get the result using the task ID

Replace {task_id} with the task_id value returned by the previous API call. The task_id is valid for queries for 24 hours.

curl -X GET https://dashscope.aliyuncs.com/api/v1/tasks/{task_id} \
--header "Authorization: Bearer $DASHSCOPE_API_KEY"

Use video effects

Supported model: wanx2.1-kf2v-plus.

Upload only the first-frame image with a built-in effect template -- no prompt or last-frame needed.

Parameters:

template: Required. Specify the effect name (e.g., mech1). Before calling the API, check the video effect list to confirm your model supports the effect -- unsupported effects cause failures.
first_frame_url: Required. Provide the first-frame image.
last_frame_url: Ignored. When using effects, this field has no effect. Leave it empty or omit it.
prompt: Ignored. When using effects, this field has no effect. Leave it empty or omit it.

First frame	Output video (with effect)

Python SDK

Requires DashScope Python SDK ≥ 1.25.8. Upgrade if needed.

import os
from http import HTTPStatus
from dashscope import VideoSynthesis
import dashscope

# This URL is for the Beijing region. URLs differ by region. Get your region's URL: https://help.aliyun.com/en/model-studio/image-to-video-by-first-and-last-frame-api-reference
dashscope.base_http_api_url = 'https://dashscope.aliyuncs.com/api/v1'

# If you have not set an environment variable, replace the line below with: api_key="sk-xxx"
# API keys differ by region. Get your API key: https://help.aliyun.com/en/model-studio/get-api-key
api_key = os.getenv("DASHSCOPE_API_KEY")

def sample_async_call_kf2v():
    # Asynchronous call returns a task_id
    rsp = VideoSynthesis.async_call(api_key=api_key,
                                    model="wanx2.1-kf2v-plus",
                                    first_frame_url="https://ty-yuanfang.oss-cn-hangzhou.aliyuncs.com/lizhengjia.lzj/tmp/11.png",
                                    resolution="720P",
                                    template="mech1",
                                    watermark=True)
    print(rsp)
    if rsp.status_code == HTTPStatus.OK:
        print("task_id: %s" % rsp.output.task_id)
    else:
        print('Failed, status_code: %s, code: %s, message: %s' % (rsp.status_code, rsp.code, rsp.message))

    # Wait for asynchronous task to complete
    rsp = VideoSynthesis.wait(task=rsp, api_key=api_key)
    print(rsp)
    if rsp.status_code == HTTPStatus.OK:
        print(rsp.output.video_url)
    else:
        print('Failed, status_code: %s, code: %s, message: %s' % (rsp.status_code, rsp.code, rsp.message))


if __name__ == '__main__':
    sample_async_call_kf2v()

Java SDK

Requires DashScope Java SDK ≥ 2.22.6. Upgrade if needed.

import com.alibaba.dashscope.aigc.videosynthesis.VideoSynthesis;
import com.alibaba.dashscope.aigc.videosynthesis.VideoSynthesisParam;
import com.alibaba.dashscope.aigc.videosynthesis.VideoSynthesisResult;
import com.alibaba.dashscope.exception.ApiException;
import com.alibaba.dashscope.exception.InputRequiredException;
import com.alibaba.dashscope.exception.NoApiKeyException;
import com.alibaba.dashscope.utils.JsonUtils;
import com.alibaba.dashscope.utils.Constants;

public class Image2Video {
    static {
        // This URL is for the China (Beijing) region. URLs differ by region. Get your URL: https://help.aliyun.com/en/model-studio/image-to-video-by-first-and-last-frame-api-reference
        Constants.baseHttpApiUrl = "https://dashscope.aliyuncs.com/api/v1";
    }

    // If you have not set an environment variable, replace the line below with: apiKey="sk-xxx"
    // API keys differ by region. Get your API key: https://help.aliyun.com/en/model-studio/get-api-key
    static String apiKey = System.getenv("DASHSCOPE_API_KEY");

    public static void image2video() throws ApiException, NoApiKeyException, InputRequiredException {
        VideoSynthesis vs = new VideoSynthesis();
        VideoSynthesisParam param =
                VideoSynthesisParam.builder()
                        .apiKey(apiKey)
                        .model("wanx2.1-kf2v-plus")
                        .firstFrameUrl("https://ty-yuanfang.oss-cn-hangzhou.aliyuncs.com/lizhengjia.lzj/tmp/11.png")
                        .template("mech1")   /* Effect template */
                        .resolution("720P")
                        .watermark(true)
                        .build();
        // Asynchronous call
        VideoSynthesisResult task = vs.asyncCall(param);
        System.out.println(JsonUtils.toJson(task));
        System.out.println("please wait...");

        // Get result
        VideoSynthesisResult result = vs.wait(task, apiKey);
        System.out.println(JsonUtils.toJson(result));
    }

    public static void main(String[] args) {
        try {
            image2video();
        } catch (ApiException | NoApiKeyException | InputRequiredException e) {
            System.out.println(e.getMessage());
        }
        System.exit(0);
    }
}

curl

Step 1: Create a task to get the task ID

curl --location 'https://dashscope.aliyuncs.com/api/v1/services/aigc/image2video/video-synthesis' \
    -H 'X-DashScope-Async: enable' \
    -H "Authorization: Bearer $DASHSCOPE_API_KEY" \
    -H 'Content-Type: application/json' \
    -d '{
    "model": "wanx2.1-kf2v-plus",
    "input": {
        "first_frame_url": "https://ty-yuanfang.oss-cn-hangzhou.aliyuncs.com/lizhengjia.lzj/tmp/11.png",
        "template": "mech1"
    },
    "parameters": {
        "resolution": "720P",
        "watermark": true
    }
}'

Step 2: Get the result using the task ID

Replace {task_id} with the task_id value returned by the previous API call. The task_id is valid for queries for 24 hours.

curl -X GET https://dashscope.aliyuncs.com/api/v1/tasks/{task_id} \
--header "Authorization: Bearer $DASHSCOPE_API_KEY"

Input image

Number of images: One first-frame image and one last-frame image.
Input methods: Image URL, local file path, or Base64-encoded string.

Method 1: Image URL (HTTP API and SDK) Recommended

Public URL: HTTP or HTTPS (e.g., https://xxxx/xxx.png).
Temporary URL: OSS protocol (upload file first). Example: oss://dashscope-instant/xxx/xxx.png.

Method 2: Local file path (SDK only)

Path requirements differ by language:

Python SDK: Supports absolute and relative paths.

Operating system	Input file path	Example (absolute path)	Example (relative path)
Linux / macOS	file://{absolute or relative path}	file:///home/images/test.png	file://./images/test.png
Windows	file://{absolute or relative path}	file://D:/images/test.png	file://./images/test.png

Java SDK: Supports absolute paths only.

Operating system	Input file path	Example (absolute path)
Linux / macOS	file://{absolute path}	file:///home/images/test.png
Windows	file:///{absolute path}	file:///D:/images/test.png

Method 3: Base64-encoded string (HTTP API and SDK)

Example value: data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAABDg...... (truncated for illustration only).

Format requirement: Must follow the format data:{MIME_type};base64,{base64_data}, where:

{base64_data}: The Base64-encoded string of the image file.

{MIME_type}: The media type of the image. It must match the file format.

Image format	MIME type
JPEG	image/jpeg
JPG	image/jpeg
PNG	image/png
BMP	image/bmp
WEBP	image/webp

Sample code: Multiple image input methods

Python SDK

import base64
import os
from http import HTTPStatus
from dashscope import VideoSynthesis
import mimetypes
import dashscope

# The following is the URL for the China (Beijing) region. URLs vary by region. For the complete list, see https://help.aliyun.com/en/model-studio/text-to-video-api-reference
dashscope.base_http_api_url = 'https://dashscope.aliyuncs.com/api/v1'


# If you have not configured an environment variable, replace the following line with your Model Studio API key: api_key="sk-xxx"
# API keys differ by region. To get an API key, see https://help.aliyun.com/en/model-studio/get-api-key
api_key = os.getenv("DASHSCOPE_API_KEY")

# --- Helper function for Base64 encoding ---
# Format: data:{MIME_type};base64,{base64_data}
def encode_file(file_path):
    mime_type, _ = mimetypes.guess_type(file_path)
    if not mime_type or not mime_type.startswith("image/"):
        raise ValueError("Unsupported or unrecognized image format")
    with open(file_path, "rb") as image_file:
        encoded_string = base64.b64encode(image_file.read()).decode('utf-8')
    return f"data:{mime_type};base64,{encoded_string}"

"""
Image input methods:
Choose one of the following.

1. Public URL - Suitable for publicly accessible images.
2. Local file - Suitable for local development and testing.
3. Base64 encoding - Suitable for private images or when encrypted transmission is required.
"""

# [Method 1] Use a public image URL
first_frame_url = "https://wanx.alicdn.com/material/20250318/first_frame.png"
last_frame_url = "https://wanx.alicdn.com/material/20250318/last_frame.png"

# [Method 2] Use a local file (supports absolute and relative paths)
# Format: file:// + file path
# Example (absolute path):
# first_frame_url = "file://" + "/path/to/your/first_frame.png"  # Linux/macOS
# last_frame_url = "file://" + "C:/path/to/your/last_frame.png"  # Windows
# Example (relative path):
# first_frame_url = "file://" + "./first_frame.png"              # Replace with your actual path.
# last_frame_url = "file://" + "./last_frame.png"                # Replace with your actual path.

# [Method 3] Use a Base64-encoded image
# first_frame_url = encode_file("./first_frame.png")            # Replace with your actual path.
# last_frame_url = encode_file("./last_frame.png")              # Replace with your actual path.

def sample_sync_call_kf2v():
    print('please wait...')
    rsp = VideoSynthesis.call(api_key=api_key,
                              model="wan2.2-kf2v-flash",
                              prompt="Realistic style, a small black cat looks up at the sky curiously, the camera gradually rises from eye level, and finally captures its curious gaze from a top-down view.",
                              first_frame_url=first_frame_url,
                              last_frame_url=last_frame_url,
                              resolution="720P",
                              prompt_extend=True)
    print(rsp)
    if rsp.status_code == HTTPStatus.OK:
        print(rsp.output.video_url)
    else:
        print('Failed, status_code: %s, code: %s, message: %s' %
              (rsp.status_code, rsp.code, rsp.message))


if __name__ == '__main__':
    sample_sync_call_kf2v()

Java SDK

// Copyright (c) Alibaba, Inc. and its affiliates.

import com.alibaba.dashscope.aigc.videosynthesis.VideoSynthesis;
import com.alibaba.dashscope.aigc.videosynthesis.VideoSynthesisParam;
import com.alibaba.dashscope.aigc.videosynthesis.VideoSynthesisResult;
import com.alibaba.dashscope.exception.ApiException;
import com.alibaba.dashscope.exception.InputRequiredException;
import com.alibaba.dashscope.exception.NoApiKeyException;
import com.alibaba.dashscope.utils.Constants;
import com.alibaba.dashscope.utils.JsonUtils;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;

/**
 * Requirements:
 *      DashScope Java SDK >= 2.20.9
 * To update the Maven dependency, visit:
 *      https://mvnrepository.com/artifact/com.alibaba/dashscope-sdk-java
 */
public class Kf2vSync {

    static {
        // The following is the URL for the China (Beijing) region. If you use a model in the China (Singapore) region, replace the URL with: https://{WorkspaceId}.ap-southeast-1.maas.aliyuncs.com/api/v1
        Constants.baseHttpApiUrl = "https://dashscope.aliyuncs.com/api/v1";
    }

    // If you have not configured an environment variable, replace the following line with your Model Studio API key: apiKey="sk-xxx"
    // API keys for the China (Singapore) and China (Beijing) regions are different. To get an API key, see https://help.aliyun.com/en/model-studio/get-api-key
    static String apiKey = System.getenv("DASHSCOPE_API_KEY");

    /**
     * Image input methods (choose one):
     *
     * 1. Public URL - Suitable for publicly accessible images.
     * 2. Local file - Suitable for local development and testing.
     * 3. Base64 encoding - Suitable for private images or when encrypted transmission is required.
     */

    //[Method 1] Public URL
    static String firstFrameUrl = "https://wanx.alicdn.com/material/20250318/first_frame.png";
    static String lastFrameUrl = "https://wanx.alicdn.com/material/20250318/last_frame.png";

    //[Method 2] Local file path (file://+absolute path or file:///+absolute path)
    // static String firstFrameUrl = "file://" + "/your/path/to/first_frame.png";   // Linux/macOS
    // static String lastFrameUrl = "file:///" + "C:/path/to/your/img.png";        // Windows

    //[Method 3] Base64 encoding
    // static String firstFrameUrl = Kf2vSync.encodeFile("/your/path/to/first_frame.png");
    // static String lastFrameUrl = Kf2vSync.encodeFile("/your/path/to/last_frame.png");


    public static void syncCall() {

        Map<String, Object> parameters = new HashMap<>();
        parameters.put("prompt_extend", true);
        parameters.put("resolution", "720P");

        VideoSynthesis videoSynthesis = new VideoSynthesis();
        VideoSynthesisParam param =
                VideoSynthesisParam.builder()
                        .apiKey(apiKey)
                        .model("wan2.2-kf2v-flash")
                        .prompt("Realistic style, a small black cat looks up at the sky curiously, the camera gradually rises from eye level, and finally captures its curious gaze from a top-down view.")
                        .firstFrameUrl(firstFrameUrl)
                        .lastFrameUrl(lastFrameUrl)
                        .parameters(parameters)
                        .build();
        VideoSynthesisResult result = null;
        try {
            // Making a synchronous call. This may take a moment.
            result = videoSynthesis.call(param);
        } catch (ApiException | NoApiKeyException e){
            throw new RuntimeException(e.getMessage());
        } catch (InputRequiredException e) {
            throw new RuntimeException(e);
        }
        System.out.println(JsonUtils.toJson(result));
    }

    /**
     * Encodes a file into a Base64 string.
     * @param filePath The path to the file.
     * @return A Base64 string in the format: data:{MIME_type};base64,{base64_data}
     */
    public static String encodeFile(String filePath) {
        Path path = Paths.get(filePath);
        if (!Files.exists(path)) {
            throw new IllegalArgumentException("File not found: " + filePath);
        }
        // Detect MIME type.
        String mimeType = null;
        try {
            mimeType = Files.probeContentType(path);
        } catch (IOException e) {
            throw new IllegalArgumentException("Cannot detect file type: " + filePath);
        }
        if (mimeType == null || !mimeType.startsWith("image/")) {
            throw new IllegalArgumentException("Unsupported or unrecognized image format");
        }
        // Read file content and encode.
        byte[] fileBytes = null;
        try{
            fileBytes = Files.readAllBytes(path);
        } catch (IOException e) {
            throw new IllegalArgumentException("Cannot read file content: " + filePath);
        }

        String encodedString = Base64.getEncoder().encodeToString(fileBytes);
        return "data:" + mimeType + ";base64," + encodedString;
    }

    public static void main(String[] args) {
        syncCall();
    }
}

Output video

Number of videos: One.
Specifications: Specifications vary by model. See Video specifications.
URL expiration: 24 hours.
Dimensions: Determined by the first-frame image and the resolution setting.
- The model preserves the first-frame's aspect ratio and scales total pixel count to the target. Output dimensions are adjusted automatically to be divisible by 16 (encoding requirement).
- Example: 750×1000 input (3:4) with resolution="720P" (target ≈920K pixels) may output 816×1104 (≈0.739 ratio, ≈900K pixels, both divisible by 16).

Billing and rate limiting

For free quota and pricing details, see Wanx-Image-to-Video-First-Last-Frame.
For model rate limiting, see Wanx Series.
Billing details:
- Input is free. Output billing is based on successful video seconds generated.
- Failed calls incur no charges and don't consume free quota.
- Image-to-video also supports savings plans.

API reference

Image-to-video - first and last frames - API reference

FAQ

Q: How do I generate a video with a specific aspect ratio (such as 3:4)?

A: The API doesn't support direct aspect ratio control -- only resolution.

The resolution parameter controls pixel count, not aspect ratio. The model preserves the first-frame's aspect ratio (first_frame_url) with minor adjustments for encoding (dimensions must be multiples of 16). For 3:4 video, upload a 3:4 first-frame image.

Example: 750×1000 input (3:4) with resolution="720P" (target ≈920K pixels) may output 816×1104 (≈0.739 ratio, ≈900K pixels, both divisible by 16).

Q: Why do I get a “url error, please check url!” error when running the SDK code?

A: Ensure your SDK version meets the minimum requirement: DashScope Python SDK ≥ 1.25.8 or DashScope Java SDK ≥ 2.22.6. Older versions may show "url error, please check url!" errors. Upgrade the SDK.