MiniMax H3 768p and 2K

minimax-h3-768p and minimax-h3-2k use the same video task API. The create call returns a task object, not the finished video file.

POST /v1/videos

Poll and download:

GET /v1/videos/{task_id}
GET /v1/videos/{task_id}/content

Send JSON. Put every field at the top level. Do not wrap these fields in metadata. Image inputs must be public URLs that stay available until the task finishes. These models are not the 1440p minimax-h3 model. Do not send start_frame, end_frame, or reference_images here.

Models and prices

Billing is per generated second: duration × unit price. Failed tasks are refunded in full.

Model ID	Resolution	Flex	Official	Duration
`minimax-h3-768p`	768p	¥0.35/sec	¥0.50/sec	4–15 sec
`minimax-h3-2k`	2K	¥0.56/sec	¥0.80/sec	4–15 sec

An 8-second clip costs ¥2.80 Flex or ¥4.00 Official at 768p, and ¥4.48 Flex or ¥6.40 Official at 2K. The official route is the fastest, about 30 seconds per video. The 933 route passes face checks. Audio references are free. Reference video adds ¥0.18 per second. Each image after the fifth adds ¥0.10. H3 Context IR, for stronger multimodal context, costs ¥0.1 per call.

Parameters

Parameter	Required	Description
`model`	Yes	`minimax-h3-768p` or `minimax-h3-2k`
`prompt`	Yes	Subject, action, and camera
`duration`	No	Integer seconds, 4–15. Send it explicitly
`aspect_ratio`	No	`16:9`, `9:16`, `1:1`, `4:3`, `3:4`, `21:9`, `3:2`, `2:3`. Default `16:9`. `ratio` is accepted
`image_url`	No	Reference image for image-to-video. A URL string or `{"url":"..."}`
`start_image_url`	No	First frame. Use only together with `end_image_url`
`end_image_url`	No	Last frame

Image-to-video

Send only image_url. Do not also send first and last frame fields.

curl https://kaienapi.com/v1/videos \
  -H "Authorization: Bearer <YOUR_API_KEY>" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "minimax-h3-768p",
    "prompt": "The person slowly turns and smiles",
    "duration": 4,
    "aspect_ratio": "9:16",
    "image_url": "https://example.com/portrait.jpg"
  }'

For 2K, change model to minimax-h3-2k.

First and last frames

Send only start_image_url and end_image_url. Do not send image_url. Do not put the last frame in extra_images, and do not expect @Image2 to lock the last frame. Describe a transition from the first image to the last image. Use 8 seconds, and match the aspect ratio to the images.

curl https://kaienapi.com/v1/videos \
  -H "Authorization: Bearer <YOUR_API_KEY>" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "minimax-h3-768p",
    "prompt": "Transition smoothly from the first frame to the last frame, camera steady",
    "duration": 8,
    "aspect_ratio": "16:9",
    "start_image_url": "https://example.com/first.jpg",
    "end_image_url": "https://example.com/last.jpg"
  }'

If the two images differ a lot, a completed task does not guarantee both ends stay locked. Check the opening and ending frames before relying on the result.

Polling

Poll every 3 to 5 seconds. Stop when status is completed.

curl "https://kaienapi.com/v1/videos/$TASK_ID" \
  -H "Authorization: Bearer <YOUR_API_KEY>"

Read url from the response. That address downloads the video file directly. If status is failed, read error and do not recreate the same request indefinitely.

Getting started

Images and video

Audio

AI tools

API Reference

MiniMax H3 768p and 2K

Models and prices

Parameters

Image-to-video

First and last frames

Polling

​Models and prices

​Parameters

​Image-to-video

​First and last frames

​Polling

Models and prices

Parameters

Image-to-video

First and last frames

Polling