# MiniMax H3 Max (video)

> MiniMax H3 Max makes video with sound from text, from one first frame, or from reference media. It renders at 480p, 768p or 1080p, in any whole length from 5 to 15 seconds. It follows the prompt closely and it is one of the most affordable premium lanes.

Status: roasOS API v1.1. Catalog `model-catalog@2026-10-06.v5`, pricing `customer-pricing@2026-11-05.v15`. The endpoint `POST /v1/video/h3-max` is live. `POST /v1/generations` stays for one minor version as a deprecated alias (see "Today").

## Endpoint
POST https://api.roasos.com/v1/video/h3-max
Auth: Authorization: Bearer roasos_sk_… (scope api:write). Idempotency-Key required. quote_only / quote_id / webhook_url as in https://docs.roasos.com/llms.txt.

## Good at
The model follows the prompt closely. Name the subject, the action and the camera move plainly, and it renders them. A single take can run 15 seconds.

Every output has a generated soundtrack. To use your own voiceover or music, send `audio_url` on text-to-video or image-to-video. The audio replaces the generated sound. It is trimmed to the clip, or padded with silence when it is shorter.

The reference lane takes up to 9 images, 3 video clips and 3 audio clips, and 12 files at most. Send `references`, `video_urls` and `audio_urls`. Add `product_id` to attach the product's kit shots, and `avatar_id` to attach a saved person. Each reference clip must be 2 to 15 seconds long, and the clips of one kind must total 15 seconds or less. The prompt names the media by type and position: Image 1, Video 1, Audio 1. The platform names the product and avatar shots for you at the end of the prompt.

Text-to-video takes six aspect ratios (21:9 to 9:16). The reference lane also takes `auto` (adaptive framing). Image-to-video takes its framing from the first frame, and `end_image_url` pins the last frame. A `seed` makes a result repeatable.

## Pricing
Unit: clip. Pricing key: `h3-max`.

| request | credits |
|---|---|
| `5s_768p` | 5 |
| `10s_768p` | 10 |
| `15s_768p` | 15 |

Credits come from the roasOS pricing table (`MODEL_COSTS`) through the catalog. No other field changes the price.

## Modes
- `text-to-video`
- `image-to-video`
- `reference-to-video`

The worker derives the mode from the media fields of the request.
Provider endpoints: `minimax/h3-max/image-to-video` · `minimax/h3-max/reference-to-video` · `minimax/h3-max/text-to-video`.

## Request fields
| field | type | required | default | rule |
|---|---|---|---|---|
| `aspect_ratio` | enum | no | `16:9` | `21:9`, `16:9`, `4:3`, `1:1`, `3:4`, `9:16`, `auto`; only in `text-to-video`, `reference-to-video` |
| `audio_url` | string | no | — | https URL; ≤ 4,096 characters |
| `audio_urls` | string[] | no | — | ≤ 3 items; only in `reference-to-video` |
| `avatar_id` | string | no | — | UUID |
| `avatar_outfit` | string | no | — | ≤ 500 characters |
| `duration_seconds` | integer enum | no | `5` | `5`, `6`, `7`, `8`, `9`, `10`, `11`, `12`, `13`, `14`, `15` |
| `end_image_url` | string | no | — | https URL; ≤ 4,096 characters; only in `image-to-video` |
| `extend_of_generation_id` | string | no | — | UUID |
| `image_url` | string | no | — | https URL; ≤ 4,096 characters; only in `image-to-video` |
| `mode` | enum | no | — | `text-to-video`, `image-to-video`, `reference-to-video` |
| `product_id` | string | no | — | UUID |
| `prompt` | string | yes | — | ≥ 1 character; ≤ 10,000 characters |
| `quote_id` | string | no | — | UUID |
| `quote_only` | boolean | no | `false` | — |
| `references` | string[] | no | — | ≤ 9 items; only in `reference-to-video` |
| `resolution` | enum | no | `768p` | `480p`, `768p`, `1080p` |
| `scene_id` | string | no | — | UUID |
| `seed` | integer | no | — | 0–2147483647 |
| `video_urls` | string[] | no | — | ≤ 3 items; only in `reference-to-video` |
| `wait_timeout_seconds` | integer | no | `0` | 0–60 |
| `webhook_url` | string | no | — | https URL; ≤ 4,096 characters |

The schema is strict: a field that is not in this table returns `400 unsupported_option`. Field names are the roasOS role names, one name per role across every family.

## Media
- `avatar_id` — identity; the saved character reference sheet, with a derived portrait only where the model requires a single face or source frame
- `product_id` — product; resolves to the product image list
- `references` — style and appearance references
- `image_url` — first frame (or the single source image)
- `end_image_url` — last frame
- `scene_id` — first frame — a scene this workspace owns
- `video_urls` — reference videos
- `audio_urls` — reference or driving audio
- `audio_url` — the driving audio track

| role | items | max size | content types | duration |
|---|---|---|---|---|
| `audio_urls` | ≤ 3 | 15 MB | `audio/mp3`, `audio/mpeg`, `audio/wav`, `audio/wave`, `audio/x-wav` | — |
| `end_image_url` | ≤ 1 | 10 MB | `image/jpeg`, `image/png`, `image/webp` | — |
| `image_url` | ≤ 1 | 10 MB | `image/jpeg`, `image/png`, `image/webp` | — |
| `references` | ≤ 9 | 10 MB | `image/jpeg`, `image/png`, `image/webp` | — |
| `video_urls` | ≤ 3 | 100 MB | `video/mp4`, `video/quicktime` | — |

- Refused: `elements`, `product_images`, `reference_images`, `scene_image`, `video_url`, `voice_id`. A refused role returns `400 unsupported_option`.
- Every URL must be an immutable object on `https://cdn.roasos.com/…` that your workspace owns; any other URL is `400 reference_media_not_workspace_owned`. Upload with `POST /v1/uploads` (direct POST of the bytes to `put_url`, or a `source_url` import), then use the returned CDN URL.

## Prompt
Limit 10,000 characters. The provider expands the prompt lightly before generation ("balanced" mode, pinned).
- Name the subject, one action and one camera move. The model adds the atmosphere.
- For a 10-15 second take, describe the action as one continuous progression.
- In image-to-video, describe the motion, not the scene. The first frame owns the scene.
- On the reference lane, say what each input controls: "the product in Image 1", "the motion of Video 1".
- Direct the sound (room tone, music mood, a spoken line in quotes), or the model makes its own.
- End with "No on-screen text, no captions, no subtitles." Add text in post-production.

## Not exposed
- `prompt_expansion_mode`: pinned to `pinned to "balanced"; "disabled" and "quality" are not served`.
- `enable_safety_checker`: pinned to `provider default (on); never sent`.
- `sync_mode`: not accepted by this public endpoint.
- `negative_prompt`: not accepted by this public endpoint.
- `generate_audio`: pinned to `every output carries a generated soundtrack; there is no on/off field`.
- `cfg_scale`: not accepted by this public endpoint.
- `shot_type`: not accepted by this public endpoint.
- `multi_prompt`: not accepted by this public endpoint.

## Result
Result kind `video`. Always present: `url`.
```json
{ "data": { "id": "gen_…", "kind": "video", "model": "h3-max", "status": "completed", "result": {"url":"https://cdn.roasos.com/workspaces/ws_01/result"} } }
```
Files live on `https://cdn.roasos.com` and are immutable; a result URL can be a media input to the next call. Poll `GET /v1/jobs/{id}/status` → `{ id, status, updated_at }`, then `GET /v1/jobs/{id}/result` (`409 run_not_completed` until the job is `completed`, `failed` or `canceled`). Statuses: `queued → processing → completed | failed | canceled`.

## Example
```bash
# 1. quote — nothing is spent
curl -X POST https://api.roasos.com/v1/video/h3-max \
  -H "Authorization: Bearer roasos_sk_live_…" \
  -H "Idempotency-Key: 0f1c9e2a-h3-max-0001" \
  -H "Content-Type: application/json" \
  -d '{"quote_only":true,"prompt":"A woman holds the bottle at eye level in a bright kitchen, morning light, static camera."}'
# → 200 { "data": { "kind": "quote", "quote_id": "q_7Hk…", "credits": 5, "expires_at": "…", "confirmation": { "model": "h3-max", "example": "5s_768p" } } }

# 2. run — the same body and the same Idempotency-Key, quote_id instead of quote_only
curl -X POST https://api.roasos.com/v1/video/h3-max \
  -H "Authorization: Bearer roasos_sk_live_…" \
  -H "Idempotency-Key: 0f1c9e2a-h3-max-0001" \
  -H "Content-Type: application/json" \
  -d '{"quote_id":"q_7Hk…","prompt":"A woman holds the bottle at eye level in a bright kitchen, morning light, static camera."}'
# → 201 { "data": { "id": "gen_…", "kind": "video", "model": "h3-max", "status": "queued", "credits_reserved": 5, "links": { "status": "/v1/jobs/gen_…/status", "result": "/v1/jobs/gen_…/result" } } }

# 3. poll
curl https://api.roasos.com/v1/jobs/gen_…/status -H "Authorization: Bearer roasos_sk_live_…"
curl https://api.roasos.com/v1/jobs/gen_…/result -H "Authorization: Bearer roasos_sk_live_…"
```

## Today
`POST /v1/video/h3-max` with `prompt`, and `image_url` or `scene_id` (image-to-video), `end_image_url`, `references`, `product_id`, `avatar_id`, `video_urls`, `audio_urls`, `audio_url`, `duration_seconds` (5-15), `aspect_ratio`, `resolution` (480p|768p|1080p) and `seed`.

## See also
https://docs.roasos.com/models/video/h3-max · https://api.roasos.com/v1/catalog/video/h3-max · minimax/h3-max/image-to-video · minimax/h3-max/reference-to-video · minimax/h3-max/text-to-video