Seedance 2.5 video controls: duration, resolution, references and last-frame chaining explained

Seedance 2.5 generates clips from 1 to 30 seconds at 480P, 720P or 1080P, with billing per output second ranging from 5 credits at 480P to 21 credits at 1080P on the standard route. The model accepts prompts up to 30,000 characters, up to nine reference images, plus video and audio references, and offers toggles for audio, web search, output format and last-frame return. The write-up argues that the thirty-second limit shapes how shots are cut and that long prompts work best when each block defines one decision. Returning the last frame lets creators carry continuity from one shot to the next, while the mp4 or mov choice affects only the container. The author also cautions that the optional pre-check does not replace platform review, that 'without audio' does not guarantee silence, and that video references add input-duration charges.