MiniMax H3 Max

MiniMax H3 Max is the faster-generation variant of MiniMax H3. One request makes the picture and the sound together: a 5–15 second clip at 480P or 768P with its own dialogue, ambience and effects. The request body is MiniMax's official format with the model ID minimax-h3-max. Send it, keep the returned task ID, and read the finished video from the task. Frames and references go in as URLs.

Model IDs

See the model page for current prices.

Quick example

curl https://api.seedrouter.ai/v1/videos/generations \
  -H "Authorization: Bearer $SEEDROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "minimax-h3-max",
    "content": [
      {"type": "text", "text": "A small sailboat glides across a calm turquoise bay at sunrise, seagulls in the distance, the sound of water and wind. No text, no logos."}
    ],
    "resolution": "768P",
    "duration": 5,
    "ratio": "16:9"
  }'

Endpoint

POST https://api.seedrouter.ai/v1/videos/generations

The response is a task ({"id": "task_...", "status": "processing"}), not the finished video. Poll GET /v1/tasks/{task_id} for the result. Keep API keys in server-side code.

Parameters

The schema is strict: unknown fields are rejected rather than ignored. callback_url is not available; poll the task instead. extra is an optional strict object containing only prompt_expansion_mode. All fields reject null; omit optional fields instead.

Content items

A single image without a role is the first frame. With more than one image, every image needs a role.

Modes

The items in content decide the mode; there is no mode field.

Frames and references cannot be combined in one request. The official documentation lists last-frame-only input, but also contains a conflicting requirement to pair it with a first frame. That case has not been verified on SeedRouter. Use both frames when an ending image is required.

{
  "model": "minimax-h3-max",
  "content": [
    {"type": "text", "text": "The person in the photo speaks to camera: Follow the wind. Voice follows the reference audio."},
    {"type": "image_url", "image_url": {"url": "https://example.com/person.jpg"}, "role": "reference_image"},
    {"type": "audio_url", "audio_url": {"url": "https://example.com/voice.mp3"}, "role": "reference_audio"}
  ],
  "resolution": "768P",
  "duration": 6
}

Media inputs

Every image, video and audio item is a public HTTP(S) URL. Base64 data URIs and mm_file:// IDs are not accepted: upload the file to your own storage and pass its URL.

Reference videos are measured when the request is accepted; one whose length cannot be read is refused with nothing charged. Other limits are checked before generation, and a request that breaks one fails without charge.

Content filter

content_filter is true unless you set it. With the filter on, the request, its text and its media, is moderated before generation. A flagged request fails with code 60001 and is not charged. Set content_filter to false to skip moderation; the website Playground always keeps it on.

Pricing dimensions

Check the model pricing section for current rates. MiniMax H3 Max prices generated output seconds and reference-video seconds separately, by the output resolution. The first two images are free; every later image adds a charge.

output seconds = reported generated seconds
input seconds  = reported reference-video seconds
extra images   = max(0, reported input image count − 2)
cost = output seconds × output rate
     + input seconds × reference-video rate
     + extra images × image rate

Reference-video lengths are added together and rounded to the nearest whole second for final usage. Two 2.4-second clips therefore contribute five input seconds. Reference audio has no input charge. First and last frames count as images, so two frames alone add no image charge.

The Playground estimate rounds reference-video lengths up to cover the possible final charge. Final usage is priced at the rate captured for your request. If a complete usage report is unavailable, the accepted estimate is used. View charges in account usage history; public task responses do not include fees. Failed tasks are not charged.

Output schema

Submission returns the task:

{"id": "task_...", "model": "minimax-h3-max", "status": "processing", "created_at": 1789689600}

Get the task

GET https://api.seedrouter.ai/v1/tasks/{task_id}

Poll every 10–20 seconds until status is completed or failed. A network timeout while polling does not mean generation failed: keep the task ID and resume checking it. Do not create another task to check progress.

Completed task

{
  "id": "task_...",
  "model": "minimax-h3-max",
  "status": "completed",
  "created_at": 1789689600,
  "finished_at": 1789689740,
  "output": {
    "video_url": "https://static.seedrouter.ai/media/tasks/task_example/0.mp4",
    "resolution": "768P",
    "ratio": "16:9",
    "duration": 5
  }
}

ratio is the aspect ratio the clip was made at, including the one chosen for adaptive. The task contains the actual resolution, ratio and duration when reported. The JSON above illustrates the response shape; it is not a measured generation result.

Errors

Requests rejected before a task is created return an HTTP error with an error object and are not charged. A task that fails after acceptance returns HTTP 200 when queried, with status: "failed" and an error object.

See the shared error catalog for codes, HTTP statuses, and retry guidance.

{
  "id": "task_...",
  "model": "minimax-h3-max",
  "status": "failed",
  "error": {
    "code": 60001,
    "message": "the request was blocked by content moderation"
  }
}

If submission itself times out, check your tasks before submitting again: the first request may have been accepted.

Tips

• Describe the shot and its sound together: subject, place, camera, light, dialogue and effects.
• Write dialogue into the prompt and attach a reference audio clip when the voice should follow it.
• Draft at 480P, then select 768P when you need more detail. A new render is a separate paid request.
• Use extra: {"prompt_expansion_mode": "disabled"} for an already complete prompt, or choose balanced / quality expansion.
• Use a first and a last frame to control where a shot starts and ends; use references to keep a product, a person or a motion.
• Add no text, no logos to keep invented marks out.

Related

• MiniMax H3 Max Playground and pricing
• Download OpenAPI
• Copyable Markdown

Contract sources

Parameters follow MiniMax’s video-generation documentation. SeedRouter uses its own model ID and asynchronous task interface, URL-only media and hosted result delivery; callbacks and cancellation are unavailable. content_filter is a SeedRouter extension.