SeeDance 1.5 Pro - Unifically

Generate videos using ByteDance SeeDance 1.5 Pro with text-to-video, image-to-video, and first/last frame workflows. Supports 4–12 second durations at 480p, 720p, or 1080p with synchronized audio generation.

Model

bytedance/seedance-1.5-pro

Request types

Request type	Required inputs	Optional inputs	Notes
Text-to-video	`prompt`	`aspect_ratio`, `duration`, `resolution`, `generate_audio`, `seed`	No frame URLs
Image-to-video	`first_frame_url`	`prompt`, `duration`, `resolution`, `generate_audio`, `seed`	`prompt` optional
First/last frame	At least one of `first_frame_url` or `last_frame_url`	`prompt`, `duration`, `resolution`, `generate_audio`, `seed`	`prompt` optional when a frame URL is set. Provide `first_frame_url`, `last_frame_url`, or both

Parameters

Parameter	Type	Required	Default	Description
`prompt`	string	Conditional	`""`	Text prompt (max 5000 chars). Required for text-to-video. Optional when a frame URL is set
`aspect_ratio`	string	No	`"16:9"`	`1:1`, `3:4`, `4:3`, `9:16`, `16:9`, `21:9`
`duration`	integer	No	`4`	Output duration in seconds (4–12). Sent to provider as `frames = 24 × seconds + 1`
`resolution`	string	No	`"480p"`	`480p`, `720p`, `1080p`
`generate_audio`	boolean	No	`true`	Whether to generate synchronized audio for the output video
`seed`	integer	No	—	Seed for reproducibility. Omit for a random seed.
`first_frame_url`	string	No	`null`	First frame image URL. Formats: png, webp, jpeg, gif. Max 30 MB. Dimensions: 300–6000 px (short side). Aspect ratio: 0.4–2.5
`last_frame_url`	string	No	`null`	Last frame image URL. Same format and size limits as `first_frame_url`
`nsfw_check`	boolean	No	`true`	Check uploaded media inputs for NSFW content

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-1.5-pro",
    "input": {
      "prompt": "A dancer performing an elegant routine on a moonlit stage",
      "aspect_ratio": "9:16",
      "duration": 10,
      "resolution": "1080p"
    }
  }'

Example - Image-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-1.5-pro",
    "input": {
      "prompt": "The subject slowly turns to face the camera",
      "first_frame_url": "https://example.com/portrait.jpg",
      "duration": 8,
      "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-1.5-pro",
    "input": {
      "prompt": "The car accelerates and drives away into the sunset",
      "duration": 10,
      "resolution": "1080p",
      "first_frame_url": "https://example.com/start.jpg",
      "last_frame_url": "https://example.com/end.jpg"
    }
  }'

Response

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

Volume discounts are available for almost all models. Reach out at contact@unifically.com to discuss custom pricing.