Seedance 2.5 Draft Final — Draft-to-1080p Video Renderer
What is Seedance 2.5 Draft Final?
Seedance 2.5 Draft Final is the finishing half of ByteDance's two-step Seedance 2.5 video workflow. You first render a fast, low-cost 480p draft with seedance-2.5 using draft: true, which returns a draft_task_id. You send that id here and the model renders the exact same shot at full 1080p, keeping the draft's composition, subject, structure and motion, together with the native audio generated in the same pass. Because the prompt, references, duration, aspect ratio, seed and audio are all inherited from the draft, the final is deterministic against it: you preview cheaply, then spend the 1080p budget only on the take you approve.
Key Features
- •Draft-to-final 1080p rendering from a draft_task_id, valid for 7 days after the draft.
- •Native synchronized audio inherited from the draft, so dialogue, sound effects and ambience land already in sync.
- •return_last_frame emits the final frame as an image URL for seamless shot chaining.
- •output_codec chooses the 10-bit HEVC master (auto) or a browser-safe H.264 re-encode (h264).
- •output_format mp4 for compatibility or mov for color-accurate edit round-trips.
- •Inherits duration up to 30 seconds and every aspect ratio from the draft, including 16:9 and vertical 9:16.
Best Use Cases
The core use case is cost-controlled finishing for production video. Teams storyboard and iterate at 480p, then finalize only approved takes at delivery quality, getting the identical shot back at 1080p. In testing, a wok flambé toss finalized with fast, physically legible motion and synchronized sizzle audio; a glassblowing clip finalized in 16:9 and returned a last frame for chaining; and a wind-up toy finalized as a true vertical 1080x1920 clip for Reels and Shorts. That fits ad spots, product demos, social cutdowns and multi-shot sequences where one beat must ship clean.
Prompt Tips and Output Quality
Prompts live in the draft, not here. Write the draft with concrete nouns, one clear action and audio cues, then finalize. Set output_codec to h264 for browser playback and previews; leave it on auto only when the file goes into a grade. Use return_last_frame to build longer sequences.
FAQs
Where does draft_task_id come from? A seedance-2.5 render with draft: true (response header X-Draft-Task-ID, or video.draft_task_id on /v2).
How long is the draft_task_id valid? Seven days from the draft render.
Can I change the prompt or duration when finalizing? No. Prompt, duration, aspect ratio, seed and audio are inherited from the draft.
My video plays black with sound. Why? The auto codec is 10-bit HEVC that some Windows browsers cannot decode; set output_codec to h264.
What resolution does it output? 1080p, 24fps, with 10-bit color on the auto master.