Seedance 2.5 4K: Native 4K AI Video Generation (ByteDance)
What is Seedance 2.5 4K?
Seedance 2.5 4K is ByteDance Seed's video model running at native 3840x2160. It turns a text prompt, a starting image, or a stack of references into a coherent 4-to-30-second clip with synchronized native audio. Unlike an upscaler, the detail is generated at full 4K rather than enlarged from 1080p, and the clip ships in 10-bit colour for smoother gradients and grading headroom. A 4K render is heavy, so the model runs asynchronously: submit the request, then poll for the finished file.
Key Features
- Native 4K (3840x2160) generation, not upscaled, in 10-bit colour.
- Synchronized native audio: dialogue, sound effects, and music co-generated with the picture.
- Durations of 4 to 30 seconds in a single pass, with multi-shot Shot 1: / Shot 2: scripting.
- Up to 30 reference images, 10 reference videos and 10 reference audios, cited as @Image 1, @Video 1 and @Audio 1.
- Modes: text-to-video, image-to-video (first_frame_url), and first-to-last-frame transitions.
- Delivered as 10-bit HEVC by default; an h264 option re-encodes for any browser.
Best Use Cases
The native-4K pipeline fits professional production: commercials and product films shown on large screens, previsualization at final resolution, texture-heavy footage where fine detail sells realism, and music or performance clips that lean on synchronized audio. Reference control keeps a character or palette consistent across a shot, and single-pass durations up to 30 seconds remove the continuity breaks of stitching shorter clips.
Prompt Tips and Output Quality
Write the shot as evolving motion: subject and action first, then scene, one camera move, and sound. Favour concrete nouns over adjectives. For image-to-video, pass first_frame_url and set aspect_ratio to adaptive; avoid real human faces in first frames, which policy blocks. In testing, a 4-second 4K text-to-video of a hummingbird held crisp feather detail and airborne pollen with clean, fast wing motion.
