Seedance 2.5 video editing: green screen, camera angle, timestamps

ByteDance says Seedance 2.5 edits video by timestamp, incl. green screen and camera angle. What BytePlus documents for edits and what Sume's API lists today.

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ByteDance says Seedance 2.5 supports timestamp-level editing of audio and video, including green screen, camera perspective changes and reference-based editing. Sume's docs do not list an edit or extend mode for seedance-2.5; Sume lists video edit through gemini-omni-flash-1.1.

The claim comes from ByteDance's launch post; the API details from the BytePlus tutorial.

What does BytePlus document for editing?

In ModelArk, an omni_reference_task_type field can be set to auto, edit or extend. The tutorial's rules for the edit and extend tasks are in the table.

ModelArk edit and extend requirements for Seedance 2.5, read 2026-09-29.
TaskRequirements
EditRatio adaptive, duration -1, a reference video of 4 to 30 s
ExtendRatio adaptive, duration 4 to 30 or -1
First and last frameRatio adaptive

Can I do this through Sume?

Not as documented. POST /v1/videos has no task-type field, and seedance-2.5 on Sume takes durations of 4 to 30 seconds, so the -1 duration used for ModelArk edits does not apply. What you can do is pass a video as a reference to shape a new generation; see Seedance 2.5 video reference.

Which Sume model edits a video?

gemini-omni-flash-1.1 exposes its edit mode through the Video Router video_url field, per the video docs. See edit a video with a prompt and the Gemini Omni Flash 1.1 guide.

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