# Seedance 2.5 Parameter Reference

## Shared

| Field | Type | Values / constraints |
|---|---|---|
| `model` | string | One of the five exact model IDs below |
| `prompt` | string | Required; maximum 10,000 tokens |
| `duration` | integer | `-1` or 4 to 30; default 5, except Edit defaults to and requires `-1` |
| `quality` | string | `480p`, `720p`; default `720p` |
| `aspect_ratio` | string | Text/Reference: fixed ratios or `adaptive`; Image/Edit/Extend: `adaptive` only |
| `output_format` | string | `mp4`, `mov`; default `mp4` |
| `generate_audio` | boolean | Default true |
| `content_filter` | boolean | Default true; false is documented at 1.1x billing |
| `callback_url` | string | Optional HTTPS URL, maximum 2048 characters, no private networks |

## Text-to-Video

- Model: `seedance-2.5-text-to-video`
- No media arrays
- Optional: `model_params.web_search`

## Image-to-Video

- Model: `seedance-2.5-image-to-video`
- `image_urls`: required, one or two public JPEG, PNG, or WebP URLs
- Each image: up to 30 MB, 300 to 6000 px, ratio 0.4 to 2.5
- One image is the first frame; two images are first and last frames
- `aspect_ratio`: `adaptive` only

## Reference-to-Video

- Model: `seedance-2.5-reference-to-video`
- Generates new footage from at least one of `image_urls`, `video_urls`, or `audio_urls`
- Images: up to 30
- Videos: up to 10, 2 to 30 seconds each, 30 seconds total, 24 to 60 FPS, up to 200 MB each
- Audio: up to 10, 2 to 30 seconds each, 30 seconds total, up to 15 MB each
- Use `@image1`, `@video1`, and `@audio1` to map prompt instructions to URL order
- Do not use edit or extension intent; choose the dedicated model to avoid a runtime failure

## Video Edit

- Model: `seedance-2.5-video-edit`
- `video_urls`: required, 1 to 10; the first video is the edit target
- First target video: 4 to 30 seconds; all video inputs total no more than 30 seconds
- Optional supplementary references: up to 30 images and 10 audio clips
- `duration`: `-1` only
- `aspect_ratio`: `adaptive` only
- Prompt should begin with explicit edit intent and reference `@video1`

## Video Extend

- Model: `seedance-2.5-video-extend`
- `video_urls`: required, 1 to 10; the first video is the extension target
- Videos: 2 to 30 seconds each; all video inputs total no more than 30 seconds
- Optional supplementary references: up to 30 images and 10 audio clips
- `duration`: `-1` or 4 to 30 seconds
- `aspect_ratio`: `adaptive` only
- Prompt should say extend forward or backward and reference `@video1`

## Shared Media Notes

- Total request body is documented with a 64 MB limit
- URLs must be directly accessible by the EvoLink server
- Base64 media is unsupported