The last frame of the source becomes the conditioning state for the new segment, in the same way an input still conditions image-to-video. Motion that was underway carries through, which is why an extension picked at a moment of movement joins more convincingly than one picked on a hard stop.
Drift is the thing to watch. Each extension is conditioned on the previous one's ending, so small deviations in colour, face or set compound. Two extensions usually hold; five in a chain rarely look like the same shot as the original.
It is the honest answer to fixed clip lengths. Most generators cap a single job at a handful of seconds, and extending is how you get past that without stitching two unrelated generations together and hoping the cut hides it.
In practice
- Choose an extension point mid-motion — a static final frame gives the model nothing to continue.
- Extensions inherit the source's resolution and frame shape; you cannot change format mid-chain.
- Colour grade the whole chain at the end, not per segment, or the joins become visible.
Models that extend a clip
Catalog entries that continue an existing video past its last frame. 4 of the 331 models in the Versely catalog qualify.
| Model | Provider | Type |
|---|---|---|
| Flux 3 Extend Video | Black Forest Labs | Video |
| VEO 3.1 Extend Video | Video | |
| Grok Imagine Extend | Grok | Video |
The mistake to avoid
Chaining extensions to reach a target length. Beyond two or three the accumulated drift is usually worse than cutting to a fresh shot.
Go deeper
Runway Video Extend: Stretching Your Best Takes
A working guide to Runway Video Extend: when stretching a take beats regenerating, continuation prompts, drift limits, and the cost math for editors.
Where you will run into it
- Extend a Video's Length — Your clip ends too soon. Keep it going.
Related terms
First-last frame
First-last frame generation takes two stills, where the clip starts and where it ends, and generates the motion that gets from one to the other.
Temporal consistency
Temporal consistency is how well a generated clip keeps things the same from one frame to the next — a shirt that stays the same colour, a background that stays put.
Duration
Duration meaning: how long a generated clip runs, chosen before generation from the lengths the model supports, not trimmed after.
Image-to-video
Image-to-video animates a still you supply: the picture becomes the opening frame, and the prompt describes only what happens next.
Text-to-video
Text-to-video is generation from a written prompt alone — you describe a shot, the model invents every frame of it, and no image or footage goes in.
The all-in-one AI studio for creators. 60+ models for video, image, voice, music and lipsync — in your browser or on your phone.
Free account. Works in your browser - no install needed. The same account signs in on your phone.