Videodialogifi › Guides › Seedance 2

Seedance 2 Reference Guide

ByteDance Seedance 2 is one of the top video models available in Videodialogifi. It accepts references in three mutually exclusive modes. Mixing modes (for example sending a reference video and a first-frame URL) causes the API to reject the job with a misleading "duration" error.

Duration limits

Minimum: 4 seconds
Maximum: 15 seconds
Videodialogifi automatically clamps values outside this range.

The three reference modes

1. First-frame only

Pin the opening frame of the video to an image. The model animates forward from that frame.

{
  "first_frame_url": "https://cdn.example.com/start.jpg",
  "prompt": "A dog runs across a field at sunset"
}

2. First-frame + last-frame

Pin both endpoints. The model interpolates between them.

{
  "first_frame_url": "https://cdn.example.com/start.jpg",
  "last_frame_url":  "https://cdn.example.com/end.jpg",
  "prompt": "Smooth camera move from start to end"
}

3. Multimodal reference-to-video

Pass any combination of reference images (up to 9), reference videos (up to 3), and reference audio (up to 3). Cannot be combined with first_frame_url / last_frame_url fields.

{
  "reference_image_urls": ["https://cdn.example.com/character.jpg"],
  "reference_video_urls": ["https://cdn.example.com/motion.mp4"],
  "prompt": "The man from the reference image performs the movements shown in the reference video"
}

Workaround: use a first-frame image inside multimodal mode

If you need both a reference video (for motion) and a specific opening frame (for identity), do not send first_frame_url. Instead merge it into reference_image_urls and hint the model in the prompt:

{
  "reference_image_urls": ["https://cdn.example.com/opening-frame.jpg"],
  "reference_video_urls": ["https://cdn.example.com/motion.mp4"],
  "prompt": "Use the first reference image as the starting frame. Character performs the exact movements shown in the reference video."
}

Videodialogifi's edge function does this merge automatically when you supply both a reference video and a first-frame image.

Reference media limits

Field	Max count	Notes
`reference_image_urls`	9	300–6000 px, aspect 0.4–2.5, < 30 MB
`reference_video_urls`	3	MP4 recommended, < 100 MB
`reference_audio_urls`	3	MP3/WAV

Common errors and fixes

Error	Cause	Fix
"Total duration cannot exceed 15 seconds"	Actually a mutex violation: both frame and reference fields were sent.	Send only one mode. Merge frame images into `reference_image_urls` if you need both.
"Reference video and first/last frames are mutually exclusive"	Direct mutex rejection.	Switch to multimodal mode.
"Input image is too small / too large"	Outside 300–6000 px.	Resize before upload.

Videodialogifi-specific behaviour

When you select Seedance 2 in Videodialogifi's Video Studio:

All reference assets are uploaded to the Scaleway CDN and passed by URL.
Duration is clamped to [4, 15] s.
If both a reference video and a first-frame image are provided, the image is auto-merged into reference_image_urls and the prompt is augmented with a first-frame hint.