Generate toward a final frame

Primary agent path

Use beatra.videos.interpolate when a required last image defines the ending. Add first_frame only when the opening must also be controlled.

1. Upload the last frame, an optional first frame, and optional driving audio.
2. Call beatra.models.list with capability: "frames_to_video" for current media combinations, duration, resolution, audio support, and prices.
3. Describe the movement toward the ending, including the transition from the first frame when one is supplied.
4. Submit once with one client_request_id; poll with beatra.tasks.get.

AI guide

Tool arguments

{
  "prompt": "The product rises and rotates smoothly between the two views",
  "first_frame": { "type": "artifact", "artifact_id": "artifact_start" },
  "last_frame": { "type": "artifact", "artifact_id": "artifact_end" },
  "driving_audio": { "type": "artifact", "artifact_id": "artifact_optional_audio" },
  "resolution": "720p",
  "duration": 6,
  "client_request_id": "vid-frames-opaque-1"
}

last_frame is required; first_frame and driving_audio are optional but must be supported by the selected model. Image-driven aspect-ratio rules come from model discovery.

Models, controls, and cost

Common controls are prompt, negative_prompt, resolution, duration, aspect_ratio, seed, enhance_prompt, and watermark. Use each only according to the selected model's metadata.

Use beatra.models.list instead of a static model table. It returns selectable models, accepted frame/audio combinations, constraints, defaults, ignored fields, and customer prices. Resolution and duration normally affect cost; do not silently change them.

MiniMax H3

Set model: "minimax-h3" for a last-frame-only or first-and-last-frame H3 request. The last frame and prompt are required; the first frame is optional. Duration is 4–15 seconds. Public 720p costs 370 credits per output second; 2k costs 590. Omitting resolution with explicit H3 now defaults to 720p. H3 accepts watermark but not driving audio or the other optional controls. Supplied boundary images are free.

Wan 3.0

Set model: "wan3.0-video" or wan3.0-video-prime with first and last frames. Duration is 2–30 seconds. Do not send driving_audio. 480p is 225 credits per output second on wan3.0-video and 335 on prime.

Task status and recovery

Poll the same task through queued and running. A lost create response may be retried only with identical arguments and the same client_request_id. Swapping either frame or changing audio, prompt, or output settings requires a new ID.

REST API

Direct protocol integrations may use POST /v1/videos/frames-to-video. Follow the generated API operation. Skill + MCP is the recommended integration; REST serves custom applications.