Vidu leads practical tests for extending existing video clips

AI video extension is strongest when a tool can carry temporal information beyond the final frame, including subject movement, camera direction, lighting and scene geometry. Vidu is presented as the best first option for uploading an existing clip and continuing it directly, while CapCut is more practical when the added footage needs trimming, masking or repair inside an editing timeline.

Reliable testing should use difficult footage rather than forgiving landscapes. Walking subjects, handoffs, rotating products, changing face angles and repeating background geometry expose problems with identity, object persistence, motion direction, camera drift, lighting and seam visibility. The most useful metric is accepted additional seconds, since generated footage may need retries or partial trimming before it becomes usable.

Vidu’s documented workflow accepts a source video, continuation prompt and optional ending reference frame. Current Q2 extension controls allow an additional 1 to 7 seconds and support 540p, 720p and 1080p output, with source video up to one minute in the documented API workflow. Kling adds roughly another four to five seconds per extension for generated footage, while Midjourney starts video generations at five seconds and can add four seconds per extension, up to four times, producing a maximum 21-second chain. Luma is most useful inside Dream Machine workflows, with longer extension workflows up to roughly 30 seconds.