Seedance 2.5 Extend Video
Continue an existing video with Seedance 2.5 through the SJinn REST API
Tool Overview
Use seedance25-video-extend-api to continue an existing video with new shots while maintaining character, environment, and narrative continuity. The first video in video_urls is the source to extend; additional videos are references. Preserve that order. To change existing content, use Seedance 2.5 Edit Video.
Create tasks with POST https://sjinn.ai/api/un-api/create_tool_task, using an API key in Authorization: Bearer YOUR_API_KEY. An active membership and sufficient credits are required.
Parameters
Set tool_type to seedance25-video-extend-api and provide these fields in input:
| Parameter | Type | Required | Description |
|---|---|---|---|
prompt | string | Yes | Describe the new content to append after the source video. |
video_urls | string[] | Yes | 1–10 videos. The first is the source; the rest are references. |
image_urls | string[] | No | Up to 30 reference images; default []. |
audio_urls | string[] | No | Up to 10 reference audio files; default []. |
duration | integer | No | Requested continuation duration, 4–30 seconds; default 5. |
resolution | string | No | 480p, 720p, or 1080p; default 480p. |
All media URLs must be complete, publicly accessible HTTP/HTTPS URLs. The output aspect ratio follows the source. Do not send ratio, aspect_ratio, or mode; these fields are rejected. Fractional durations are rejected rather than rounded.
Pricing
| Resolution | Credits per second |
|---|---|
| 480P | 170 |
| 720P | 350 |
| 1080P | 850 |
The cost is duration × resolution rate. For example, an 8-second continuation at 720P costs 8 × 350 = 2800 credits.
Request Example
curl -X POST https://sjinn.ai/api/un-api/create_tool_task \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"tool_type": "seedance25-video-extend-api",
"input": {
"prompt": "Continue from the end of the first video: the character walks through the doorway into a sunlit garden, maintaining the same camera movement.",
"video_urls": [
"https://example.com/source.mp4",
"https://example.com/garden-reference.mp4"
],
"duration": 8,
"resolution": "720p"
}
}'
Response and Task Status
{
"success": true,
"errorMsg": "",
"error_code": 0,
"data": {
"task_id": "550e8400-e29b-41d4-a716-446655440000"
}
}
Poll Query Task Status with the returned task_id. A successful task returns video URLs in data.output_urls. Task records retain task_type: "seedance25-video-extend-api".