SeeDance 2.0 Fast RFR

Generate videos using ByteDance SeeDance 2.0 Fast RFR — the speed-optimized tier. Supports text-to-video, first/last frame, and multimodal reference workflows with image, video, and audio references. Output durations are 4–15 seconds at 480p or 720p.

RFR — Real Face Restriction. This model rejects reference images and videos that contain real human faces, unless the likeness is authorized on the provider side. Use the non-RFR SeeDance 2.0 Fast if your references include real people.

Model

bytedance/seedance-2.0-fast-rfr

Request types

Request type	Required inputs	Optional inputs	Notes
Text-to-video	`prompt`	`ratio`, `duration`, `resolution`, `generate_audio`	No frame or reference URLs
First/last frame	`image_urls` (1 or 2 entries)	`prompt`, `ratio`, `duration`, `resolution`, `generate_audio`	1 URL = first frame; 2 URLs = first + last frame. `prompt` optional
Multimodal reference	At least one of `reference_image_urls` or `reference_video_urls`	`prompt`, `reference_audio_urls`, `ratio`, `duration`, `resolution`, `generate_audio`	Generate, edit, or extend video from reference media. Mutually exclusive with `image_urls`

Parameters

Parameter	Type	Required	Default	Description
`prompt`	string	Conditional	—	Text prompt (max 6,000 chars; ≤500 Chinese chars or ≤1,000 English words recommended). Required when no frame images or reference media are provided. Supports Chinese, English, Japanese, Indonesian, Spanish, Portuguese. Dialogue in double quotes drives generated speech
`image_urls`	string[]	No	`null`	Frame image URLs. 1 = first frame; 2 = first + last frame. Formats: jpeg, png, webp, bmp, tiff, gif, heic, heif. Max 30 MB each. Sides: 300–6000 px. Aspect ratio: 0.4–2.5. Mutually exclusive with `reference_*` fields
`reference_image_urls`	string[]	No	`null`	Reference image URLs (max 9) for multimodal-reference generation. Same format/size constraints as `image_urls`. Must not contain real human faces
`reference_video_urls`	string[]	No	`null`	Reference video URLs (max 3) — enables video editing and extension. Formats: mp4, mov. Max 200 MB each. Duration: 2–15 s per clip, combined total ≤ 15 s. Must be publicly reachable URLs. Must not contain real human faces
`reference_audio_urls`	string[]	No	`null`	Reference audio URLs (max 3). Formats: wav, mp3. Max 15 MB each. Duration: 2–15 s per clip, combined total ≤ 15 s. Cannot be the only input — include at least one reference image or video. Must be publicly reachable URLs
`ratio`	string	No	`"adaptive"`	`adaptive`, `1:1`, `3:4`, `4:3`, `9:16`, `16:9`, `21:9`. `adaptive` picks the closest ratio from the prompt or input media
`duration`	integer	No	`5`	Output duration in whole seconds (4–15), or `-1` to let the model choose the length (billed by actual duration)
`resolution`	string	No	`"720p"`	`480p`, `720p`
`generate_audio`	boolean	No	`true`	Generate synchronized audio (voices, sound effects, background music). Output audio is mono

This model does not accept seed or camera_fixed. Output is mp4 at 24 fps.

Example - Text-to-Video

curl -X POST https://api.unifically.com/v1/tasks \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "bytedance/seedance-2.0-fast-rfr",
    "input": {
      "prompt": "A drone shot flying over a neon-lit cyberpunk city at night",
      "ratio": "16:9",
      "duration": 5,
      "resolution": "720p"
    }
  }'

Example - First & Last Frame

curl -X POST https://api.unifically.com/v1/tasks \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "bytedance/seedance-2.0-fast-rfr",
    "input": {
      "prompt": "Smooth camera pan from left to right",
      "duration": 8,
      "image_urls": [
        "https://example.com/start.jpg",
        "https://example.com/end.jpg"
      ]
    }
  }'

Example - Multimodal Reference

curl -X POST https://api.unifically.com/v1/tasks \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "bytedance/seedance-2.0-fast-rfr",
    "input": {
      "prompt": "Transform the background of the clip to match the reference scenery",
      "duration": 8,
      "reference_image_urls": [
        "https://example.com/scenery.jpg"
      ],
      "reference_video_urls": [
        "https://example.com/clip.mp4"
      ]
    }
  }'

Frame image_urls are fetched server-side, so they only need to be reachable by Unifically. Reference video/audio URLs are forwarded to the provider directly and must be publicly downloadable.

Response

{
  "code": 200,
  "success": true,
  "data": {
    "task_id": "abc123def456",
    "status": "processing"
  }
}

​Model

​Request types

​Parameters

​Example - Text-to-Video

​Example - First & Last Frame

​Example - Multimodal Reference

​Response

Model

Request types

Parameters

Example - Text-to-Video

Example - First & Last Frame

Example - Multimodal Reference

Response