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POST
/
api
/
v1
/
veo
/
extend
Extend Veo3.1 Video
curl --request POST \
  --url 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"
}'
{
  "code": 200,
  "msg": "success",
  "data": {
    "taskId": "veo_extend_task_xyz789"
  }
}
Extend an existing Veo3.1 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 Billing Details for full details).
CapabilityDetails
Smart ExtensionGenerate new video segments based on existing videos and text prompts
Seamless ConnectionExtended videos naturally connect with the original video
Flexible ControlPrecisely control the style and actions of extended content through prompts
High-Quality OutputMaintain the same quality and style as the original video
Audio TrackExtended videos default to background audio, consistent with the original video

​
Why our Veo 3.1 Video Extension is different

  1. Smart Content Understanding – Deeply understands the content and style of the original video to ensure coherence of extended content.
  2. Natural Transition – Extended video segments seamlessly connect with the original video without visible splicing marks.
  3. Flexible Control – Precisely control the actions, scenes, and styles of extended content through detailed prompts.
  4. 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:
  1. Provide Original Video: Use the taskId from the original video generation task
  2. Describe Extension Content: Use prompt to detail how you want the video to be extended
  3. Smart Analysis: The system analyzes the content, style, and actions of the original video
  4. Generate Extension: Generate new video segments based on analysis results and your prompts
  5. Seamless Connection: Naturally connect the extended video with the original video

​
Request Parameters

​
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.
​
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.
​
seeds
integer
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.
​
watermark
string
Watermark text (optional). If provided, a watermark will be added to the generated video.
​
callBackUrl
string
Callback URL when the task is completed (optional). Strongly recommended for production environments.

​
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 Billing Details for specific pricing

​
Best Practices

​
Prompt Writing Suggestions

  1. 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”
  2. Maintain Style Consistency: Ensure the style of extended content matches the original video
  3. Natural Transition: Described actions should naturally connect with the end of the original video
  4. Use English: Recommend using English prompts for best results
  5. Avoid Conflicts: Ensure extended content doesn’t create logical conflicts with the original video

​
Technical Recommendations

  1. Use Callbacks: Strongly recommend using callback mechanisms to get results in production environments
  2. Download Promptly: Download video files promptly after generation, URLs have time limits
  3. Error Handling: Implement appropriate error handling and retry mechanisms
  4. Credit Management: Monitor credit usage to ensure sufficient balance
  5. 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 Billing 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

  • 404 Error: Check if task_id and media_id are correct
  • 400 Error: Check if the prompt complies with content policies
  • 402 Error: Confirm the account has sufficient credits
  • 500 Error: Temporary server issue, please try again later
  • Unnatural Connection: Try more detailed prompt descriptions
  • Style Inconsistency: Ensure the prompt includes style descriptions
  • Disconnected Actions: Check if action descriptions in the prompt are reasonable
  • Content Deviation: Adjust prompts to more accurately describe desired extension content
  • Callback Receipt Failure: Check if the callback URL is accessible
  • Video Download Failure: Confirm URL validity and network connection
  • Abnormal Task Status: Use the details query interface to check task status
  • Insufficient Credits: Recharge credits promptly to continue using the service

Authorizations

​
Authorization
string
header
required

All APIs require authentication via Bearer Token.

Get API Key:

  1. Visit API Key Management Page to get your API Key

Usage: Add to request header: Authorization: Bearer YOUR_API_KEY

Body

application/json
​
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

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.

Required range: 10000 <= x <= 99999
Example:

12345

​
watermark
string

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

Example:

"MyBrand"

​
callBackUrl
string

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
Example:

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

Response

Request successful

​
code
enum<integer>

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
Available options:
200,
400,
401,
402,
404,
422,
429,
455,
500,
501,
505
​
msg
string

Response message

Example:

"success"

​
data
object
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