Text Models
Image Models
Video Models
Generate a Video from a Video
Use CometAPI Runway POST /runwayml/v1/video_to_video to start video-to-video generation tasks, set X-Runway-Version, and transform source clips.
curl --request POST \
--url https://api.cometapi.com/runwayml/v1/video_to_video \
--header 'Authorization: Bearer <token>' \
--header 'Content-Type: application/json' \
--header 'X-Runway-Version: <x-runway-version>' \
--data '
{
"videoUri": "https://media.w3.org/2010/05/sintel/trailer.mp4",
"promptText": "Make the motion feel cinematic.",
"model": "gen4_aleph",
"references": [
{
"type": "image",
"uri": "https://res.cloudinary.com/demo/image/upload/dog.jpg"
}
],
"ratio": "1280:720"
}
'{
"id": "12a01a5e-ab55-4aa7-b002-7b873546cf76"
}Use this endpoint to transform an existing source clip with Runway’s video-to-video workflow. It starts an async task instead of returning the final output immediately.Documentation Index
Fetch the complete documentation index at: https://apidoc.cometapi.com/llms.txt
Use this file to discover all available pages before exploring further.
Before you call it
- Prepare a source video that matches the provider’s input requirements
- Include the required
X-Runway-Versionheader for the feature set you want - Start with one short prompt that describes the change, not a full storyboard
Task flow
Poll task details
Authorizations
Bearer token authentication. Use your CometAPI key.
Headers
Runway API version header, for example 2024-11-06.
Body
HTTPS URL of the source video, or a base64 data URI containing the video.
Text prompt describing the desired output. Maximum 1000 characters.
Random seed for reproducible results. Range: 0–4294967295.
Model variant to use.
Optional reference images to guide generation. Each item must include type (e.g. image) and uri (HTTPS URL).
Show child attributes
Show child attributes
Aspect ratio of the output video, e.g. 1280:720.
Show child attributes
Show child attributes
Response
success
The ID of the task that was created. Use this to retrieve the task later.
curl --request POST \
--url https://api.cometapi.com/runwayml/v1/video_to_video \
--header 'Authorization: Bearer <token>' \
--header 'Content-Type: application/json' \
--header 'X-Runway-Version: <x-runway-version>' \
--data '
{
"videoUri": "https://media.w3.org/2010/05/sintel/trailer.mp4",
"promptText": "Make the motion feel cinematic.",
"model": "gen4_aleph",
"references": [
{
"type": "image",
"uri": "https://res.cloudinary.com/demo/image/upload/dog.jpg"
}
],
"ratio": "1280:720"
}
'{
"id": "12a01a5e-ab55-4aa7-b002-7b873546cf76"
}