Extend Veo3.1 Video

POST

/api/v1/veo/extend

Extend an existing Veo 3.1 video by generating new content based on the original video and a text prompt. This feature allows you to extend video duration or add new content based on your existing video clips.

Our Veo 3.1 Video Extension API is more than simple video splicing. It layers intelligent extension algorithms on top of the official models, giving you greater flexibility and markedly higher success rates - 25% of the official Google pricing (see pricing details for full details).

Capability	Details
Smart Extension	Generate new video segments based on existing videos and text prompts
Seamless Connection	Extended videos naturally connect with the original video
Flexible Control	Precisely control the style and actions of extended content through prompts
High-Quality Output	Maintain the same quality and style as the original video
Audio Track	Extended videos default to background audio, consistent with the original video

Why our Veo 3.1 Video Extension is different #

Smart Content Understanding - Deeply understands the content and style of the original video to ensure coherence of extended content.

Natural Transition - Extended video segments seamlessly connect with the original video without visible splicing marks.

Flexible Control - Precisely control the actions, scenes, and styles of extended content through detailed prompts.

Significant Cost Savings - Our rates are 25% of Google's direct API pricing.

Video Extension Workflow #

The video extension feature is based on your existing Veo3.1 generated videos and works through the following steps:

Provide Original Video: Use the taskId from the original video generation task

Describe Extension Content: Use prompt to detail how you want the video to be extended

Smart Analysis: The system analyzes the content, style, and actions of the original video

Generate Extension: Generate new video segments based on analysis results and your prompts

Seamless Connection: Naturally connect the extended video with the original video

Extension Features #

Through the video extension feature, you can:

Extend video duration and add more content

Change video direction and add new actions or scenes

Add new elements while maintaining the original style

Create richer video stories

Extension Features:

Smart Analysis: Deeply understand the content and style of the original video

Natural Connection: Extended content seamlessly connects with the original video

Flexible Control: Precisely control extended content through prompts

Quality Assurance: Maintain the same quality and style as the original video

Important Notes

Can only extend videos generated through the Veo3.1 API

Extended content must also comply with platform content policies

Recommend using English prompts for best results

Video extension consumes credits, see pricing Details for specific pricing

Best Practices #

Prompt Writing Suggestions

Detailed Action Description: Clearly describe how you want the video to be extended, e.g., "the dog continues running through the park, jumping over obstacles"

Maintain Style Consistency: Ensure the style of extended content matches the original video

Natural Transition: Described actions should naturally connect with the end of the original video

Use English: Recommend using English prompts for best results

Avoid Conflicts: Ensure extended content doesn't create logical conflicts with the original video

Technical Recommendations

Use Callbacks: Strongly recommend using callback mechanisms to get results in production environments

Download Promptly: Download video files promptly after generation, URLs have time limits

Error Handling: Implement appropriate error handling and retry mechanisms

Credit Management: Monitor credit usage to ensure sufficient balance

Seed Control: Use the seeds parameter to control the randomness of generated content

Important Notes #

Important Limitations

Original Video Requirements: Can only extend videos generated through the Veo3.1 API

Content Policy: Extended content must also comply with platform content policies

Credit Consumption: Video extension consumes credits, see pricing Details for specific pricing

Processing Time: Video extension may take several minutes to over ten minutes to process

URL Validity: Generated video URLs have time limits, please download and save promptly

Extended Video Features

Seamless Connection: Extended videos will naturally connect with the original video

Quality Maintenance: Extended videos maintain the same quality as the original video

Style Consistency: Extended content will maintain the visual style of the original video

Flexible Control: Prompts can precisely control the content and direction of extension

Troubleshooting #

Common Error Handling

Extension Quality Issues

Technical Issues

Callbacks

onVideoExtended

POST

Request

Authorization

Bearer Token

Provide your bearer token in the Authorization header when making requests to protected resources.

Example:

Authorization: Bearer ********************

Body Params application/jsonRequired

Generate Code

taskId

string

required

Task ID of the original video generation. Must be a valid taskId returned from the video generation interface. Note: Videos generated after 1080P generation cannot be extended.

Example: veo_task_abcdef123456

prompt

string

required

Text prompt describing the extended video content. Should detail how you want the video to be extended, including actions, scene changes, style, etc.

Example: The dog continues running through the park, jumping over obstacles and playing with other dogs

seeds

integer

optional

Random seed parameter for controlling the randomness of generated content. Range: 10000-99999. Same seeds will generate similar video content, different seeds will generate different video content. If not specified, the system will automatically assign random seeds.

= 10000<= 99999

Example: 12345

model

enum<string>

optional

Model type for video extension (optional). Defaults to fast if not specified.

fast: Fast generation mode

quality: High quality generation mode

lite: Most cost-effective generation mode

Allowed values: fastqualitylite

Default: fast

Example: fast

watermark

string

optional

Watermark text (optional). If provided, a watermark will be added to the generated video.

Example: MyBrand

callBackUrl

string

optional

Callback URL when the task is completed (optional). Strongly recommended for production environments.

The system will send a POST request to this URL when video extension is completed, containing task status and results

The callback contains generated video URLs, task information, etc.

Your callback endpoint should accept POST requests with JSON payloads containing video results

For detailed callback format and implementation guide, see Video Generation Callbacks

Alternatively, you can use the get video details interface to poll task status

To ensure callback security, see Webhook Verification Guide for signature verification implementation

Example: https://your-callback-url.com/veo-extend-callback

Examples

Responses

🟢200

application/json

Request successful

Bodyapplication/json

Generate Code

code

enum<integer>

optional

Response status code

200: Success - Extension task created

400: Client error - Prompt violates content policy or other input errors

401: Unauthorized - Authentication credentials missing or invalid

402: Insufficient credits - Account does not have enough credits to perform the operation

404: Not found - Original video or task does not exist

422: Validation error - Request parameter validation failed

429: Rate limit - Exceeded the request limit for this resource

455: Service unavailable - System is under maintenance

500: Server error - Unexpected error occurred while processing the request

501: Extension failed - Video extension task failed

505: Feature disabled - The requested feature is currently disabled

Allowed values: 200400401402404422429455500501505

msg

string

optional

Response message

Example: success

data

object

optional

taskId

string

optional

Task ID that can be used to query task status via the get video details interface

Example: veo_extend_task_xyz789

🔴500Error

Request Request Example

Shell

JavaScript

Java

Swift

PHP

Python

HTTP

Objective-C

Ruby

OCaml

Dart

cURLcURL-WindowsHttpiewgetPowerShell

curl --location 'https://api.kie.ai/api/v1/veo/extend' \
--header 'Authorization: Bearer <token>' \
--header 'Content-Type: application/json' \
--data '{
  "taskId": "veo_task_abcdef123456",
  "prompt": "The dog continues running through the park, jumping over obstacles and playing with other dogs",
  "seeds": 12345,
  "watermark": "MyBrand",
  "callBackUrl": "https://your-callback-url.com/veo-extend-callback",
  "model": "fast"
}'

Response Response Example

200 - Example 1

{
    "code": 200,
    "msg": "success",
    "data": {
        "taskId": "veo_extend_task_xyz789"
    }
}

Extend Veo3.1 Video ​

Why our Veo 3.1 Video Extension is different # ​

Video Extension Workflow # ​

Extension Features # ​

Best Practices # ​

Important Notes # ​

Troubleshooting # ​

Callbacks ​

onVideoExtended ​

Request ​

Responses ​

Extend Veo3.1 Video

Why our Veo 3.1 Video Extension is different #

Video Extension Workflow #

Extension Features #

Best Practices #

Important Notes #

Troubleshooting #

Callbacks

onVideoExtended

Request

Responses