FLUX 3 Extend Video: Continue a Clip From Its Last Frame
Last verified: October 29, 2026
FLUX 3 Extend Video takes a clip you upload and generates new seconds that begin where its last frame ends. The new seconds follow the action you write in the prompt, and when Generate Audio is on they come back with sound made in the same run. Use it when a take is good but stops a beat too soon: a walk that should reach the door, a pour that should finish, a conversation that needs one more line.
FLUX 3 picks up from the final frames of your clip and carries its momentum, framing and scene logic forward without a cut. The new footage does not have to stay on the last pose, though. In Black Forest Labs' own demonstration, a continuation takes a couple out of an alley and into a market and keeps the scene's logic and sound. That is the range to aim for: the same scene, moving on.
The form splits the job in two. The uploaded clip supplies everything already on screen, and the prompt supplies what happens next. Video Duration sets how much new footage you get, Resolution sets how sharp it is, and the Generate Audio switch decides whether the extension comes back with sound.
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FLUX 3 Extension Settings at a Glance
The inputs, lengths, output sizes and audio options you get for each run.
Input
Video (MP4, up to 50 MB) + a text prompt of up to 2,048 characters
Video Duration
5 to 20 seconds
Resolution
720P or 1080P
Audio
Switch on or off, on by default
Output
1 video per run
Techniques for a Clean FLUX 3 Continuation
Write the Next Beat, Not a Recap
Trim the Source So Its Ending Sets Up the Shot
Write the Prompt as Prose in Time Order
How Do I Extend a Video With FLUX 3?
Five steps from your source clip to a downloaded extension.
Add your clip in "Video"
Click the upload area in "Video" and choose the clip you want to continue. The new seconds are generated from its end, not its beginning, so trim it first to stop on the moment you want carried on. Keep within the format, size and length limits shown under the field.
Describe what happens next in "Prompt"
Write the action that follows the last frame, what the camera does and what the new seconds should sound like. The "Prompt" box takes up to 2,048 characters, which is plenty if you skip describing what the clip already shows.
Set "Video Duration" and "Resolution"
"Video Duration" runs from 5 to 20 seconds in one-second steps and starts at 5. "Resolution" offers 720P, the default, or 1080P. Test at 5 seconds and 720P to see whether the seam holds, then raise the length and switch to 1080P for the version you plan to keep.
Check the audio and click "Generate"
Before you click "Generate", check the "Generate Audio" switch. It is on by default, so the extension comes with sound unless you turn it off. Leave it on when the source has dialogue or ambience to carry on, and switch it off if you will add your own soundtrack.
Download the result
Each run returns one video. Before you download, play the point where your footage ends and the new seconds begin. If the motion or sound jumps there, change the prompt and run it again rather than trying to hide the jump in the edit.
Extending a Clip vs Generating a New One
Choose between continuing footage you already have and starting a new FLUX 3 shot from text.
| Criterion | FLUX 3 continuation | Alternatives | Best For |
|---|---|---|---|
| Starting material | You bring an existing video, and the new footage starts from where that video ends. | The Text To Video workflow starts from nothing but your prompt, so you don't need any footage before the first run. | Choose continuation when a take already exists and just runs short; choose text to video when the first shot hasn't been made yet. |
| Fit with a take already in your edit | The new seconds open on the frame your clip ends on, so they are built to follow that take directly. | A text-to-video clip is generated from your description alone and joins your existing footage as a separate shot. | Pick continuation when the extra seconds must play straight on from a take in your timeline, and pick text to video when the edit calls for a cut to a fresh shot. |
Why Doesn't My Extension Continue Smoothly?
Common problems with FLUX 3 extensions, and what to change before you run again.
The extension cuts to a different shot instead of continuing the one I uploaded.
My video won't upload.
The prompt box won't take my full description.
The extension came back with sounds I didn't ask for.
Frequently Asked Questions
Can I keep extending the same video with FLUX 3?
Yes, by running extensions one after another. Download the result and check that the file still meets the Video field's format, size and length limits. Then add it as the new source and write a prompt for the next beat. Each run continues from the end of the file you upload, so make sure its final seconds show the moment you want to carry on from.
What video files can I upload to extend?
Click the upload button in the Video field and choose one MP4 file of up to 50 MB and no longer than 20 seconds. The new seconds continue from where that file ends, so the ending is the part to get right.
Can I extend footage that wasn't made with FLUX 3?
Yes. Continuation starts from a clip you already have and keeps it going. The Video field accepts any MP4 within its limits, whether you shot it, edited it or generated it earlier.
Why does one extension cost more than another?
The credit cost of a run is worked out from the options you choose and shown above the Generate button once you are signed in. It changes with Video Duration and Resolution, so a quick test and a final render with different settings will show different costs.