Question 1

How long can a single Seedance 2.5 clip be?

Accepted Answer

Up to 30 seconds in one continuous pass — no stitching required, with audio generated alongside the video.

Question 2

Does it generate sound?

Accepted Answer

Yes. Footsteps, engines, ambience and score are produced in the same pass as the pixels and matched to on-screen action, rather than added afterwards.

Question 3

How many references can I use?

Accepted Answer

Up to 50 multimodal inputs — faces, products, wardrobe, locations and style frames — and the direction they set applies across the full clip. That is 30 images, 10 clips and 10 audio takes; each clip and each audio take runs 2–30 seconds, and each kind totals at most 30 seconds.

Question 4

Can I fix one detail without regenerating?

Accepted Answer

Yes. Describe the change and Seedance 2.5 repaints just that region — swap a label, clean a background or change wardrobe while the rest of the clip stays untouched. On the Edit input the clip is named @Video1 and keeps its own length and shape.

Question 5

Which aspect ratios are supported?

Accepted Answer

Anything from vertical 9:16 through 16:9 to widescreen 21:9 — plus 1:1, 4:3 and 3:4, or Auto to let the model pick. Animating a still and editing a clip both take their shape from the source.

Question 6

Does 2.5 render 4K?

Accepted Answer

No. Seedance 2.5 tops out at 1080p; 480p and 720p are the other two options.