Extend a video · Seedance 2.5
Extend a video with AI
Seedance 2.5 extend carries a clip on from where it ends, with sound, adding 4 to 30 seconds in one run. It runs in the Root app, on a clip you made in Root or one you upload. Extending a 10-second clip by 5 seconds at 720p is up to $3.61.
Updated
First month free on the Beginner plan, with 650 credits to try any model.
AI video made in Root
What Seedance 2.5 extend does
- Makes new footage that carries the shot on from the last moment of your clip.
- You choose how much to add, from 4 to 30 seconds, in whole seconds.
- Makes sound with the new footage. You can turn it off, and the price is the same either way.
- Works at 480p, 720p or 1080p.
- Takes a clip up to 30 seconds long. If yours is longer, the node says so and offers to trim it.
- Takes reference images, clips and sound as well, to keep a character, a product or a look the same.
- Gives you the new footage as its own take, next to your clip. Put the two one after the other on Root's timeline.
What an extension costs
Seedance 2.5 extend at 720p, in dollars, by the length of your clip and how much you add. 100 credits is $1.
| Your clip | Add 5 s | Add 10 s | Add 15 s |
|---|---|---|---|
| 5 s | up to $2.41 | up to $4.09 | up to $6.01 |
| 10 s | up to $3.61 | up to $4.81 | up to $6.01 |
| 15 s | up to $4.81 | up to $6.01 | up to $7.21 |
| 30 s | up to $8.41 | up to $9.61 | up to $10.81 |
“Up to” is the most it can cost; you are charged what the model reports it used. A 10-second clip extended by 5 seconds is up to $1.68 at 480p and up to $8.89 at 1080p.
How the price is worked out
You pay for the new seconds plus the seconds of your clip, because Seedance reads the whole clip to carry it on. Your clip counts as at least two-thirds of the new footage, so a very short clip is billed as if it were that long. Any reference clips you wire in add their length too. Each second is billed at a lower rate than for a clip made from a prompt, because a clip is wired in.
| Your clip | New footage | Seconds billed | Why |
|---|---|---|---|
| 10 s | 5 s | 15 | 5 new, plus your 10-second clip |
| 3 s | 15 s | 25 | 15 new, plus 10: two-thirds of the new footage, which is longer than your clip |
| 30 s | 30 s | 60 | 30 new, plus your 30-second clip |
How to extend a clip in Root
- Wire the clip into an Edit Video node. Add an Edit Video node to the project and wire the clip you want to carry on into its “clip to extend” input. A clip you upload works the same way.
- Choose Seedance 2.5 extend. Pick it from the node's list. Set Length to the seconds you want to add, from 4 to 30, and pick 480p, 720p or 1080p.
- Say what happens next. Write what happens after the last moment: the action, where the camera goes, what we hear. Wire in reference images if a character or product must stay the same.
- Run it, then cut the two together. The price shows before you run it. The new footage lands next to your clip; drag both onto the timeline, one after the other.
Another way: start from the last frame
If the next shot does not need to carry on the same movement, take your clip's last frame with the Extract Frame node, which is free, and wire it into a Video Gen node as the first frame of a new shot. A 5-second Seedance 2.5 shot from a frame at 720p is up to $2.03, with nothing billed for the old clip.
The difference: Extend reads the whole clip, so it can carry on the motion and the sound. A shot from the last frame starts from that one picture only.
Related guides
Extend video questions
How do I extend a video with AI?
In Root, wire the clip into an Edit Video node, choose Seedance 2.5 extend, set how many seconds to add and say what happens next. Extending a 10-second clip by 5 seconds at 720p is up to $3.61. The new footage follows on from the last moment of your clip, with sound.
How much does it cost to extend a video?
It depends on your clip as well as the new footage: you pay for the new seconds plus the seconds of your clip, and the clip counts as at least two-thirds of the new footage. So 5 seconds added to a 10-second clip is billed as 15 seconds, up to $3.61 at 720p. The price shows before you run it, and you are charged what the model reports it used.
How much can I add to a clip in one go?
From 4 to 30 seconds in one run. To go further, extend the new footage again: wire it into another Edit Video node and run Seedance 2.5 extend on it.
Can I extend a video I shot myself?
Yes. Upload it to a project and wire it into the Edit Video node, the same as a clip made in Root. It can be up to 30 seconds long; the node offers to trim a longer one.
Does the extended part have sound?
Yes, Seedance 2.5 makes sound with the new footage. You can turn it off on the node, and the price stays the same.
Where does Seedance 2.5 extend run?
In the Root app, on the Edit Video node. Seedance 2.5 itself runs in the Root app, by API, and from Claude and ChatGPT, for new clips from a prompt or from images.
Can I try extending a video for free?
For a month, yes. The first month of Root's Beginner plan is free and comes with 650 credits, enough for one 5-second extensions of a 10-second clip at 720p. After that the plan is $9 a month, and you can cancel whenever you like.
Try Root free for a month
The first month of the Beginner plan is free and comes with 650 credits to spend on any model. After that it's $9 a month, and you can cancel whenever you like.