AI video longer than ten seconds

Video models are sold as a menu of durations, not a dial. One renders exactly 5 or 10 seconds; the realtime model renders 5, 10 or 15. Past that, the only way to a longer video is more than one clip, and the question becomes how the clips join.

The simple way starts each clip on the last frame of the previous one. It works, and every small error in one clip becomes the starting point of the next, so a face or a room slowly wanders. The robust way plans the story first as a series of stills, then generates each clip between two of them.

Four stills generated independently from four descriptions are four different people in four different rooms, and pinning clips between them only interpolates between strangers. So each still in a story is an edit of the one before it: same person, same place, the next moment. That is the whole trick that keeps a long video one video.

A 45 second video has to be built from clip lengths the model offers. A planner that only knows a maximum will ask for nine second clips, get five second ones back, and deliver 25 seconds while quoting 45. Percify refuses a total it cannot render exactly rather than quietly handing you a shorter video.

Three and ten minute videos are prepared but not switched on. If what you need is a long talking person rather than a long scene, that is a different tool: lip sync runs from the audio, and a talking head can run for minutes. See the talking head generator.